EP2231940B1

EP2231940B1 - Railway arch linings and mezzanine floors

Info

Publication number: EP2231940B1
Application number: EP20080835682
Authority: EP
Inventors: Steven Caffall FINCH
Original assignee: Individual
Current assignee: Finch Steven Caffall
Priority date: 2007-10-03
Filing date: 2008-10-03
Publication date: 2015-05-06
Anticipated expiration: 2028-10-03
Also published as: JP5630764B2; EP2231940A2; US20090090070A1; GB201017666D0; JP2011516754A; GB201017665D0; GB2475138A; GB2453840A; AU2008306580B2; GB0818127D0; GB2474936A; GB201017669D0; AU2008306580A1; GB2474936B; GB2475138B; WO2009044277A3; GB2475137A; GB2453840B; GB2475137B; GB201017667D0

Description

This invention relates to systems, methods and apparatus for lining arched structures and for installing mezzanine floors, particularly in railway arches.
Railway arches are the spaces defined between the adjacent piers of an arched viaduct supporting a railway line, and are commonly adapted to accommodate light industrial, storage, retail, office and other commercial activities. Other arched structures include tunnels, vaults and the like.
A viaduct comprises a plurality of spaced-apart, usually parallel piers, each being a masonry structure extending transversely across the width of the viaduct and upwardly from a foundation, with an arched masonry structure known as a barrel supported between each adjacent pair of piers so that its soffit or intrados (the downwardly facing, curved surface) meets each pier along a usually horizontal line, not always visually discernible, known as the spring.
The width of the arch is thus defined as the horizontal distance between the respective piers in the transverse direction of the arch, which is typically parallel with the longitudinal axis of the viaduct; and the length of the arch as the length of the piers in the longitudinal direction of the arch, corresponding to the width of the viaduct The overall height of the arch is the vertical distance between the arch floor or ground surface and the crown, which is an imaginary line extending along the length of the arch at the uppermost part of the soffit, typically equidistant between the respective piers.
The inwardly facing surfaces of the piers (i.e. the surfaces facing inwardly into the arch) thus define the generally vertical sides of the arch, while the two ends of the arch are often closed by freestanding walls defining a front entrance and, optionally, windows. Where the height of the arch permits, an additional floor (herein termed a mezzanine floor) may also be provided at an upper level. Railway arches are usually damp and dirty and are often severely affected by rainwater which penetrates through the masonry and drips continuously from the soffit The whole interior surface of the arch (piers and soffit) must therefore be lined so as to intercept the water and divert it, typically to narrow soakaways formed between the base of each pier and the adjacent edge of a concrete floor slab, and/or to gutters arranged at or below the spring.
Railway arches vary widely in their dimensions and in the geometry of the soffit, which for example may conform to a cylindrical surface, or may be flattened at the crown, or may be ellipsoidal with the minor radius at the crown. The spring may range in height from below ground level to many tens of metres above ground level, although for most commercially usable arches it is likely to be of the order of about 1m - 15m above ground level.
In order to maximise the available space within the arch, it is important that the lining should conform as closely as possible to the surface of the soffit, and piers while providing a continuous downward fall to carry water from the crown to the ground. Conventionally, the lining comprises overlapping corrugated plastics sheets which are screwed or nailed to horizontal battens fixed at spaced intervals to the soffit and piers. Each fixing passing through the corrugated sheets must be sealed to prevent water penetration.
In order to ensure their structural integrity, railway arches are subject to regular inspections, and in the United Kingdom a major inspection is typically carried out every ten years. This requires the sheets, battens and any interior structure to be entirely removed so that the masonry can be inspected and repointed or replaced as required. The arch is then re-lined with new materials. Over the years, numerous fasteners are inserted into the soffit and piers, and the repeated drilling damages the masonry while the fasteners corrode to leave voids which weaken the barrel and encourage water penetration.
The size and geometry of a railway arch often poses significant access problems when lining the soffit. For example, an average lined arch might be six metres in width and seven metres in height at the crown, with a height of four metres at the spring. Since the soffit curves away on either hand, it is impossible to support an ordinary ladder to safely reach the crown. A scaffolding tower is also inconvenient since it provides only a small working area and must be repeatedly moved as the work progresses. It is time consuming and difficult to drill multiple fixing holes into the soffit overhead and to accurately align the fixings with holes in the battens. Masonry is a heterogeneous material, comprising bricks and mortar joints of varying hardness as well as old, corroded fasteners and localised voids. It is therefore likely that the drill will wander or will need to be repositioned so as to avoid local obstructions.
GB 2 383 804 discloses an arch lining system comprising a plurality of overlapping tiles supported on a framework. The framework comprises a central, galvanized steel water deflection plate, which is fixed along the crown of the arch, and a set of spaced-apart frame elements, each comprising an outer, galvanized steel water deflection plate and an inner, aluminium extrusion, which are arranged in pairs to extend downwardly along the curve of the soffit in opposite directions from the central deflection plate on either side of the crown. The deflection plates are fixed to the soffit by means of expanding bolts. Once the framework is in place, the tiles are fixed in horizontal rows between the aluminium extrusions, so that the central portion of the lower edge of each tile extends downwardly behind the upper edge of the tile below, forming a continuous surface which sheds water. The ends of each tile are sealed against the aluminium mouldings by means of neoprene gaskets, while any water falling onto the zone above the tile ends is diverted by the galvanized steel deflection plates to the central portion of the tiles on either side.
The system of GB '804 advantageously provides for inspection of portions of the brickwork by selective removal of the tiles, but it is not clear whether the system is able to accommodate variations in the curvature of the soffit without compromising the waterproof seal between the tiles and the aluminium extrusions.
Disadvantageously, the expanding bolts apply a point load in an inward direction away from the soffit, which may dislodge individual bricks from the barrel. Moreover, the system of GB '804 relies on gaskets to seal the penetrations of the expanding bolts through the deflection plates, so that the integrity of the waterproof lining depends on the waterproof seal provided by each of the gaskets.
It is a general object of the present invention to provide an improved system and corresponding methods and apparatus which may be used in installing a lining and/or a mezzanine floor in an arched structure, particularly a railway arch.
Accordingly in its several aspects the present invention provides a system and corresponding methods and apparatus as variously defined in the claims.
In this specification, a lining may comprise a waterproof inner covering (sheets, panels, or the like) and/or a framework supporting lighting or other fixtures.
The novel framework comprising a plurality of elongate, flexible frame elements, which may be supported by stanchions at either side of the arch, is easily installed within an arched structure without inserting any fixings into the soffit or piers, so that the attendant problems of water penetration and structural damage are entirely avoided. Moreover, the flexible frame elements are adapted to be cut to length and re-joined as required and adapt automatically to the geometry of the arch in which they are installed. Each installation can thus be accomplished using standard, interchangeable and largely re-usable components, and requires neither complex measurement nor customised parts.
The invention recognises that it is possible to provide a framework which is entirely self supporting - which is to say, a framework which is capable of transferring its own weight, plus the load imposed upon it by lining panels, lighting fixtures and the like, to the ground - but which nevertheless relies upon contact with the pre-existing masonry structure to provide it with rigidity and stability. Alternatively, each flexible frame element may comprise locking joints which confer sufficient inherent rigidity to permit the frame element to be mechanically decoupled from the soffit in the installed position, which may be advantageous in ensuring compliance with applicable regulations.
Since each flexible frame element does not need to provide the inherent rigidity and resistance to wind and other external loading required of an independent, freestanding structure, it may consequently be surprisingly long and small in profile compared with its load carrying capacity, making it relatively light in weight and cheap to manufacture. By engaging each flexible frame element pressingly against the soffit during installation, the whole lining may be accommodated within an envelope of no more than about, say, 50mm - 75mm from the inner surface of the arch, maximising the available space in the lined arch.
The long, narrow, flexible frame elements are preferably supplied, bound together in pairs so as to form a rigid assembly which is easy to transport, and are easily installed without specialist access equipment by means of the novel installation tools which permit the majority of the installation work to be carried out at ground level. Once in place, the novel framework may be used to support a working platform or mezzanine floor which affords easy access for attachment of the lining sheets or panels beneath the soffit After installation, the frame elements and panels may provide conduits and attachment points for wiring, small diameter pipework, lighting and power fixtures, and the like.
More specific objectives as well as further features and advantages will be understood from the following description in which some illustrative embodiments of the various elements of the invention are set forth, purely by way of example and without limitation to the scope of the invention, and with reference to the accompanying drawings, in which:

Figs. 1-11 illustrate sequential steps in the installation of a first embodiment of the novel system in a railway arch;
Figs. 14A - 14C are end views respectively of a first stanchion, a first, unitary frame element incorporating a first, plastic deformation element, and the first frame element attached to the first stanchion;
Fig. 14D is an end view of two first frame elements strapped together as supplied for transportation;
Fig. 15 is a front view of part of the first stanchion;
Figs. 16A and 16B are respectively a rear view and a side view of one end of the first frame element;
Fig. 17 is a side view of part of the first stanchion;
Figs. 19A and 19B are respectively a rear view and a side view of one hinge portion of the first frame element of Fig. 16A, showing the first, plastic deformation element after a first stage of deformation;
Figs. 19C and 19D correspond to Figs. 19A and 19B and show the first frame element after a second stage of deformation;
Figs. 21B and 21C are respectively rear and side views of one rigid section of a third, articulated frame element incorporating a third, resilient deformation element, prior to assembly;
Figs. 24B and 24C are respectively front and side views of one hinge portion of the third frame element after assembly, showing the third, resilient deformation element;
Fig. 24D corresponds to Fig. 24C and shows the third frame element during installation;
Figs. 25A and 25B are respectively a front view and a side view of a jointing bar for use in joining together two short frame elements to form a longer frame element;
Figs. 26A and 26B are respectively a side view and an end view of a second jointing bar with a cable tray;
Fig. 27A is a cross-section of a first, preferred shield after extrusion and prior to rolling;
Fig. 27B is a perspective view of the first shield after rolling;
Figs. 28A and 28B are enlarged views respectively of the central attachment portion and of one longitudinal water guiding structure of the first shield;
Figs. 29 and 30 are cross-sections through the first shield attached respectively to the preferred stanchion of Fig. 80 and to the preferred frame element of Fig. 85;
Figs. 33C and 33D show alternative resilient deformation elements for use with the articulated frame element;
Fig. 34A is a rear view of a first panel, in which the central portion is cut away to show both of its ends;
Fig. 34B is a longitudinal section through the first panel at B - B in Fig. 34A;
Fig. 34C is a lower end view of the first panel as shown in Fig. 34A;
Figs. 37A - 37C are cross sections showing the cooperating upper and lower ends of two first panels after installation respectively near the crown, near the spring line, and on stanchions adjacent the piers of a railway arch;
Fig. 37D shows the rear water shedding surface of the panel in an alternative embodiment;
Fig. 39 is a section through part of an installed lining at the crown of a railway arch, parallel with the longitudinal axis of the arch;
Fig. 40 is a section through part of another installed lining lower down on the soffit of another railway arch, parallel with the longitudinal axis of the arch;
Fig.41B shows a first releasable mounting mechanism of a first installation tool, respectively before and after attachment to a third stanchion;
Fig. 43 is a section at X43 - X43 in Fig. 41B, showing the lower end of the first releasable mounting mechanism in the engaged position;
Figs. 44 is a front view of a first movement mechanism of the first tool with the front cover removed, showing the ratchet drive pawls in the disengaged position;
Fig. 45 is a longitudinal section through the first movement mechanism at X45 - X45 and X45' - X45' in Fig. 44, with the front cover in place, showing the first tool mounted on the third stanchion of Fig. 41B;
Fig. 53 is a front view showing the frame element attachment mechanism of the first tool in use, in which the first tool is mounted on the first stanchion of Fig. 15 and the first frame element of Fig. 16A is attached to the tool and raised into the vertical position, with the front casing of the first tool cut away and the detent mechanism shown in scrap view in the locked position;
Fig. 54 is a side view of the first tool in use as shown in Fig. 53, showing the detent mechanism in the locked position;
Fig. 58 is a front view showing the first tool attached to the first stanchion, in which the pivot assembly has been fully rotated, the detent mechanism has returned to the disengaged position, and the first frame element has been attached to the tool prior to raising it to the vertical position as shown in Fig. 53;
Fig. 60 is a side view corresponding to Fig. 54 but showing the first tool after actuation of the separation adjustment mechanism, with the first frame element fully engaged with the first stanchion;
Fig. 63 shows the pivot frame assembly with the front protection plate removed;
Figs. 75 and 76 illustrate an alternative embodiment in which the tools are motorised, and in which: Fig. 75 shows a remote control unit, and Fig. 76 shows a control system cooperating with the remote control unit;
Figs. 80 - 86 show particularly preferred embodiments of the stanchion and frame element for use with the first shield, in which:
- Fig. 80 is a cross-section through the stanchion;
- Fig. 81 shows a bracket assembly for attaching a bracing strut to the stanchion;
- Fig. 82 shows the bracket assembly attached to the stanchion;
- Fig. 83 shows a second bracket assembly for use in attaching a joist to the stanchion;
- Fig. 84 shows the second bracket assembly in use;
- Fig. 85 is a cross-section through the frame element; and
- Fig. 86 shows the frame element engaged with the stanchion;
Figs. 90A and 92B are respectively a plan and a side view showing the installation of a column mounting assembly in a railway arch;
Fig. 93 is a plan view showing the first stanchion mounted on the column mounting assembly;
Figs. 96 - 101 show a modular temporary flooring system, in which: Fig. 96 is a side view of a first modular flooring element; and Fig. 101 is a top view of a modular floor formed from a plurality of interlocking modular flooring elements;
Figs. 114A and 114B are respectively a side and a rear view of one rigid section of a fourth frame element having locking joints, prior to assembly;
Fig. 115 shows the first end of the rigid section of the fourth frame element;
Figs. 116B and 117 are respectively a cut-away view and a longitudinal section showing the opposite sidewall of the second end of the rigid section of the fourth frame element;
Figs. 118A, 118B and 118E are respectively a right-hand side, left-hand side, and end view of the cartridge frame, prior to injection moulding;
Figs. 119B and 119E correspond to Figs. 118B and 118E, showing the cartridge frame after injection moulding;
Figs. 126A and 126B are respectively a left side view and a front view of the complete cartridge with the retaining clip in position;
Fig. 129 is a cut-away view of one hinge portion of the fourth frame element after assembly;
Fig. 130B shows the hinge portion of the fourth frame element in the installed position beneath the soffit, illustrating the remote operation of the joint locking mechanism;
Figs. 131A and 132A are side views respectively of the first and second ends of one rigid section of a fifth frame element having locking joints, prior to assembly;
Figs. 136A - 136C are respectively a left side, top and end view of the latch frame;
Figs. 137A and 137B are respectively a top and end view of the latch plate;
Fig. 142 is a cut-away view of one hinge portion of the fifth frame element after assembly;
Figs. 143A - 143C are respectively a side, rear and front view of one rigid section of a sixth frame element having weldable joints, prior to assembly;
Fig. 150A shows one hinge portion of the sixth frame element after assembly;
Fig. 153 shows an adapted tool with the sixth frame element in use;
Fig. 155 shows a flexible jointing bar used to provide a permanently flexible joint in the centre of the sixth frame element; and
Fig. 156 shows a further adaptation of the installation tool of Fig. 153 for use with the flexible jointing bar.

It should be noted that small, repetitive details such as fixing apertures and hinge components are not shown in the views of Figs. 1 - 11, and for full understanding, reference should be made to the individual component drawings in which these details are depicted.
Corresponding parts are indicated by the same reference numerals in each of the figures.
Referring to Fig. 1, a brickwork railway arch 1 comprises a barrel 2 which is supported by two parallel piers 3, 3' whose respective opposite, inwardly facing vertical surfaces 4, 4' are spaced apart by about 5.5 metres in the transverse (width) direction W of the arch to define the two sides of the arch. The lower surface of the barrel forms an arched soffit 5 which intersects the sides 4, 4' of the arch to define two horizontal spring lines 6, 6' at a height of about 3.5 metres above the arch floor 7.
The soffit curves upwardly and inwardly as shown from the spring lines on either side of the arch towards an imaginary horizontal crown line 8 at its uppermost part, which extends longitudinally along the arch, parallel with the piers and equidistant between the two sides 4, 4' at a height of about 6 metres above the floor. The arch extends for a length of about 11 metres in its longitudinal direction L to a freestanding wall 9 at its rear end, and is open at its front end so that we can see what's happening. (Normally the front end would be closed with a corresponding wall or shutter.)
The floor 7 comprises a concrete slab which is spaced from each pier by a narrow soakaway 10, 10'.

Overview

Each flexible frame element can be a single length of top hat steel section, with the central U-shaped channel divided into portions by cut lines which leave the flanges intact to form deformable hinge portions. Alternatively the element can comprise a plurality of individual lengths of top-hat section pivotably riveted together.
The stanchions also comprise top-hat sections, preferably with tubular reinforcing portions, and are arranged in opposed pairs, one every two metres down each side of the arch. A length of extruded polyethylene shield is interposed between the rear wall of each stanchion (which faces the brickwork) and the pier. A tool is then mounted on each stanchion at floor level, and a mount on the top of the tool is pivoted about its axis (which is orthogonal to the plane of the pier) by releasing a ratchet until the mount lies on an axis slanting slightly down from horizontal towards one end of the arch. One end of the flexible frame element is releasably attached to the mount Preferably, each flexible frame element is in two separate parts, and the corresponding end of the other part is attached to the other tool on the opposite stanchion. The two parts are then brought together manually in a generally horizontal plane and joined by a jointing bar in the centre of the floor of the arch, so that the frame element forms into an arched shape assisted by springs or plastic deformation elements at its joints. A length of flexible shield is attached to the central web of the flexible frame element It is then raised into a vertical plane, supported by the ratchets, and the tools are then driven simultaneously up the stanchions until the frame element (carrying the shield with it) engages pressingly against the soffit. The mount can also be moved axially along its pivot axis so as to bring the frame element (top hat section) into nested sliding engagement with the stanchion, flanges against flanges. Continued upward movement of the tools engenders a hoop stress which conforms the frame element flexibly to the geometry of the soffit, after which the frame element is bolted to the stanchion.
The arch is thus lined with a series of hoops, each comprising a flexible frame element pressed against the curved soffit between the spring lines at either end and supported by a pair of vertical stanchions. In a development, the joints can be locked (e.g. by simultaneous or sequential resistance projection welding in series), following which the tools can be lowered very slightly to relieve the hoop stress from the soffit, Panels are then attached between the hoops to form a complete water shedding lining, with the lengths of flexible shield overlapped to define a dry zone covering the stanchions and the frame elements.
Once in place, the stanchions may be used to support a temporary working platform or mezzanine floor which affords easy access for attachment of the panels beneath the soffit, while the hoops provide conduits and attachment points for wiring, small diameter pipework, lighting and power fixtures, and the like.

Simple baseplates

In accordance with a first embodiment, installation commences by spacing out a series of mounting bases, which in their simplest form comprise flat attachment plates or baseplates 20 on the floor along the base of each pier. The baseplates are set out in pairs, one on either side of the arch and aligned in the transverse direction of the arch, at a spacing which corresponds to the length of a panel plus the width of a stanchion, as further described below. Conveniently, these components are dimensioned so that the baseplates are spaced apart by an easily measured distance, which in the example shown is 2 metres. The first pair of baseplates are arranged adjacent the front end of the arch, and the final (seventh) pair are arranged adjacent the rear wall 9 so that the spacing between the last two baseplates on each side is reduced to correspond to the length of the arch.
Each baseplate 20 comprises a flat steel plate which is bent upwardly to form an angled portion at its rear edge. A hole is formed in each corner of the angled portion for attachment of bracing wires as further described below. A short bracket is welded to the plate so that its rear wall extends for a short distance beyond the angled portion, and its two side walls are provided with fixing holes and slots which correspond respectively to the rear apertures 47 and front fixing holes 48 in the stanchions 40, as further described below.
Each plate is bolted to the floor slab 7 by small expanding bolts, so that the rear wall is spaced about 5mm from the inner surface 4, 4' of the respective pier and overhangs the soakaway 10, 10'. The plates need only light fixing sufficient to locate the base of the respective stanchion adjacent the pier and to support the stanchion in an upright position during installation, as will now be described. Once the framework is in place, the fixings do not play any part in supporting it.
The initial fixing of the baseplates is the only stage at which any drilling is required, and also the only stage at which the arch needs to be measured so as to accurately locate components, since subsequent steps in the installation are all dependent on the position of the baseplates. Since the principal measurement and all of the drilling is carried out on the floor, it is a very easy task compared with the conventional method of lining in which most of the work is done high up under the soffit.
Once the baseplates are in position, support means are attached to the baseplates along each side of the arch for supporting the flexible frame elements. Of course, each of the stanchions could alternatively include a suitable baseplate, so that it is fixed directly to the floor slab without the need for a separate mounting base.

Simple stanchions

Referring to Figs. 14A - 17, the support means comprise a plurality of first rolled steel stanchions 40, each formed from a unitary length of mild steel plate formed into an elongate "top hat" profile comprising a central, U-shaped portion with a pair of oppositely directed lateral flanges 41. In this specification a stanchion is synonymous with a column, post or pillar.
Referring particularly to Fig. 15, each flange 41 is perforated with an array of panel fixing holes 42, 42' which receive self-tapping fixing screws for the attachment of lining panels 200 to the stanchion, as further described below. The panel fixing holes 42 are arranged in groups, the groups being spaced apart in the vertical (longitudinal) direction of the stanchion by a distance d₁. The corresponding groups of fixing holes and slots in the panel flanges 205 are spaced apart in the vertical direction by a repeat distance d₂, in which d₂ = (d₁ - (d₁ / n)) wherein n is a whole number. This provides a fixing system in which the vertical position of each panel is finely adjustable according to the principle of a Vernier scale in increments of (d₁ / n) with one coincidence (providing a pair of aligned fixing holes) occurring at a distance of (d₂.n), i.e. every (n - 1) groups of holes 42.
The four fixing holes 42 within each group are spaced apart in the horizontal or transverse direction and in the vertical or longitudinal direction of the stanchion 40 by small distances, which in the vertical direction are not a factor of the increment (d₁ / n) and so provide for still finer vertical as well as horizontal adjustments in the position of the panels 200 between the increments (d₁ / n). Each panel can thus be fixed in any required vertical position.
In addition to the panel fixing holes, each flange 41 is provided with a series of regularly spaced rectangular apertures 43, and a further series of regularly spaced elongate apertures 44 with rounded ends.
The rectangular apertures 43 receive the projecting teeth 471 of the drive pinion 470 of the first installation tool 300, as further described in due course, so as to form a rack, while the flanges 41 provide an installation tool mounting structure which receives the mounting mechanism 301 of the installation tool so as to releasably mount the installation tool for sliding movement up and down the stanchion 40. The rack can also be used to support shelving or pallet racking arranged at the sides of the arch.
The elongate apertures 44 provide windows which are so dimensioned and positioned that at least one of each diagonal pair of panel fixing holes 78 in the corresponding flange 71 of a first frame element 70 (visible in Fig. 16A and further described below) when attached to the first stanchion 40 (as shown in Fig. 14C) coincides, either with a rectangular aperture 43 or with an adjacent elongate aperture 44. The longitudinal spacing d₃ between alternate panel fixing holes 78 in the first frame element also corresponds to the spacing between the fixing holes in the panel flanges according to the Vernier principle, so this arrangement ensures that every respective coincidence between the corresponding fixing holes in the frame element flange and in the panel flange is available for attachment of the panel to the frame element, with the fixing screw passing through the corresponding aperture 43 or 44 in the stanchion, when the frame element is attached to the stanchion as shown in Fig. 14C.
Referring particularly to Fig. 17, the central, U-shaped portion of the first stanchion comprises a rear wall 45 and two side walls 46, each side wall being provided with a series of rear apertures 47 adjacent the rear wall 45, and with frame element mounting or attachment means comprising two series of front fixing holes 48, 49 adjacent the respective flange 41.
The rear apertures 47 provide fixing points for the attachment of bracing wires and bracing struts as well as for attaching the stanchion to the baseplate, as will shortly be described. They are spaced apart from the flanges 41 by a sufficient horizontal (transverse) distance to avoid the corresponding U-shaped portion of the first frame element when it is inserted into the stanchion, as most clearly seen in Fig. 60.
The front fixing holes 48, 49 of each series are spaced apart in the vertical (longitudinal) direction by a distance d₄, corresponding to the longitudinal spacing d₅ of two corresponding series of fixing holes 79 in each corresponding side wall 76 of the first frame element 70 (Fig. 16B), wherein d₄ = (d₅ - (d₅ / n)) and n is a whole number.
This provides another fixing system on the Vernier principle, defining a range of positional adjustment between the frame element and the stanchion such that respective ones of the fixing holes in each series 48, 49 are brought consecutively into alignment with corresponding ones of the fixing holes 79 in the first frame element 70, each consecutively aligned pair of holes defining a through-hole for receiving a bolt 50 (Fig. 14C) for attaching the frame element to the stanchion, as the first frame element 70 is displaced axially along the first stanchion 40 through the incremental distance (d₅ / n).
By way of example, where d₅ = 35.0mm and n = 10, d₄ = 31.5mm, providing one coincidence every (d₄.n) = (d₅.(n -1)) = 315mm at an incremental axial displacement of no more than 3.5mm from any given axial position of the frame element relative to the stanchion.
Whereas the corresponding two rows of apertures 79 in each side wall 76 of the first frame element 70 are aligned in parallel, the corresponding front apertures 48, 49 of the first and second series of the first stanchion are spaced apart by a longitudinal (vertical) distance d₆ = (d₅ / 2). This doubles the number of repeat coincidences between corresponding apertures in the first frame element 70 and first stanchion 40, providing one coincidence alternately in the first series 48 and second series 49 of front fixing holes for every ((n - 1) / 2) fixing holes 79 of the first frame element 70, i.e. spaced apart by a distance ((d₄.n) / 2), for any given incrementally displaced position of the first frame element 70.
Of course, the relative spacings d₄ and d₅ could be reversed.
In a simple form, the two cooperating elements are thus provided with respective first and second series of apertures spaced apart respectively by the distance x and by the distance (x ± y), so that corresponding apertures of the first and second series are brought consecutively into alignment by relative axial displacement of the two elements through the incremental distance y. Preferably however, y = (x/n) wherein n is a whole number, providing a large number (which may be many times n) of repeat coincidences with a very small and consistent increment throughout the full range of axial movement, in accordance with the Vernier principle described.

Installation of simple stanchions

Referring to Fig. 2, each stanchion 40 is first cut to length as required using an angle grinder or the like so that it extends in its installed position to just below the spring line 6, 6'. A length of shield material 149 (further described below) is then attached to the rear wall 45 of the stanchion so that it extends from the bottom of the stanchion to about half a metre above the top of the stanchion, and the stanchion is then placed over the bracket 24 of the respective baseplate 20 (which fits slidingly between the side walls 46) and attached by means of bolts passing via the rear apertures 47 and front fixing holes 48. Once mounted on the baseplate, the rear wall of the stanchion extends into the small gap between the rear wall of the bracket and the inner surface of the pier, so that the stanchion is supported in a vertical position just above the upturned rear edge of the bracket with the flanges 41 facing inwardly into the arch and the shield sandwiched between its rear wall 45 and the pier. This allows water to run down between the inner surface 4, 4' of the pier and the shield 149, behind the rear edge of the bracket and straight into the soakaway 10, 10'.
Once in position, each stanchion (other than those at the front and rear of the arch) is braced against rotational movement about its base parallel with the plane of the pier (i.e., prevented from toppling over in the longitudinal direction of the arch) by means of two small galvanised steel tension cables 67, one on either side of the stanchion, each being attached at its upper end to one of the rear apertures 47 close to the top of the stanchion and at its lower end to a galvanised turnbuckle 68 fixed to one of the holes in the baseplate of the adjacent stanchion. The turnbuckles are tightened to tension both cables, while the stanchion is checked for verticality by means of a plumb-bob or, conveniently, a spirit level with a vertical vial. Any water running down the cable will drip off the turnbuckle into the soakaway at its base.
The front and rear stanchions on either side of the arch are braced to their respective adjacent stanchions by means of a horizontal bracing strut 60, 60'. Each bracing strut comprises a tubular body with a long internal thread at each end. A series of external collars are spaced apart near each end so as to prevent water from running horizontally along the strut in front of the shields. One end of the strut 60 is attached to the upper end of the stanchion 40. The other end of the strut is attached to an elongate stud which is welded to a bracket 65 bolted to apertures 47 of the adjacent stanchion. The body is rotated to advance it along the stud and adjust the spacing between the two stanchions.
After the installation of lining panels as further described below, the panels will also support the stanchions in vertical alignment
The stanchions 40 are now restrained in the longitudinal direction L by the bracing wires and struts and outwardly in the width direction W by the piers, so their only freedom of movement is now by rotation of the upper ends of the stanchions inwardly in the width direction W, away from the piers and into the arch. This movement is resisted prior to installation of the flexible frame elements by the small expanding bolts at the base of each stanchion. Once the flexible frame elements are fixed to the stanchions as will now be described, and during the process of installing them, their load (including the hoop stress applied during installation, and the load placed on them after installation by the lining, lighting fixtures etc.) braces the upper ends of the stanchions 40 outwardly in the width direction W towards the piers, so that the entire framework is stabilised and rigidified without attachment to the masonry of the arch at any point It is then impossible for the framework to collapse under load, provided that its component parts are of adequate strength.

Preferred stanchion and frame element

The top-hat configuration of the stanchion advantageously provides a rack for sliding/rolling engagement by the tool, and the flanges provide attachment points for the panels, while the body of the panel extends rearwardly of the flanges so that the flanges define the approximate plane of the interior surface of the finished arch lining. The central U-shaped recess also receives the frame element and functions as a cabling channel. However, top-hat section may be vulnerable to buckling at higher slenderness ratios.
Referring to Figs. 80 - 86, a preferred stanchion 600 (Fig. 80) is roll-formed from steel strip to form an elongate profile defining a central recess 601 with a pair of oppositely directed lateral flanges 602, the edges of the strip being continuously welded at the joint 603. The central recess comprises two spaced-apart rear walls 604, 605 and two side walls 606 arranged between the rear walls and the flanges. Each of the flanges defines a respective tubular section 607 (by which is meant a portion closed in cross-section), while the rear walls define a third tubular section 608. Advantageously, each of the side walls 606 comprises two layers of steel, which may be rigidified by spot welding them together, the mounting holes 609 for attachment of the flexible frame element being penetrated through both layers. The tubular flanges 602 and the tubular rear wall portion 608 resist local buckling, stiffening the section and greatly increasing its axial loadbearing capacity so that it is suitable for use in supporting a mezzanine floor.
The rear tubular section is penetrated by spaced-apart apertures 610 which receive the curved end 620 of a first bracket element 621 (Fig. 81). A cooperating second bracket element 622 carrying a stud 624 is inserted into an aligned aperture 611 in the tubular flange 602, and the two bracket elements are bolted together (the bolt engaging in a threaded hole 623 in the first bracket element 621 and extending through it into the mounting hole 609) so as to fix the stud 624 to the stanchion as shown in Fig. 82, the stud then being used as required for attachment of a bracing strut 60 or cable 67.
A joist (not shown) may be attached to the stanchion using a pair of brackets 630 (Fig. 83), each having a vertical array of fixed studs 631 and threaded holes 632, the studs 631 being inserted into the mounting holes 609 in the double thickness side walls 606 so as to rapidly provide a satisfactory shear connection which is secured by only two bolts inserted via adjacent mounting holes 609 into corresponding adjacent threaded holes 632 in the brackets. The vertical web of the joist (not shown) is received between the two brackets, while the central recess 601 of the stanchion remains available for cables 629 as shown in Fig. 84. The brackets 630 are waisted 633 so as to leave the flanges 602 clear to receive the mounting portions of the panels and accommodate lateral variations in stanchion spacing.
The rear tubular section 608 is provided with two grooves 612 to receive the ribs 155 of the attachment portion of the first shield 150 (Fig. 28A) in snap-fit relation, as shown in Fig. 29.
Fig. 85 shows a preferred, one-piece flexible frame element 640 having a generally top-hat configuration with corresponding grooves 641, which similarly receive the ribs 155 of the shield 150 so as to retain it in snap-fit relation as shown in Fig. 30. The holes 642 for attachment to the preferred stanchion are formed through the grooves 641, which are cut away to receive rectangular nuts 643 (or rectangular headed bolts) as shown in Fig. 86, so that the frame element nests inside the stanchion 600, flange against flange.

Alternative stanchion and footplate

Referring to Fig. 93, a footplate 1030 is welded to the lower end 1000' of an alternative stanchion and serves to mount the stanchion on the base element of a column mounting assembly as further described below. The footplate comprises a rigid, flat steel plate arranged orthogonally to the longitudinal axis of the stanchion and having a mounting portion comprising a circular hole forming a central aperture. The centroid C of the stanchion, i.e. its centre of mass when considered in cross-section, most preferably coincides with the centre of the hole as shown, so that the stanchion may be pivotably balanced on the central support which is received in the hole as further described below. The footplate also has an array of three smaller apertures which are spaced apart from and arranged around the central hole to receive lateral support studs, the footplate being fixed to the studs by means of nuts which are adjusted to set the column in a vertical orientation and restrain it against tilting.
In alternative embodiments, such as where the column is made from universal column section, i.e. having a central web, part of the column may be cut away to accommodate the central support. In alternative embodiments for more general use, the lateral support studs could be welded at the respective corners of a base element comprising a flat, square steel plate and having the central support at its centre. A similar arrangement could be adopted at each end of a beam which is laid transversely across the floor of a railway arch so as to support a suspended ground floor surface, with the base element in each case being fixed to the upwardly facing support surface, comprising the end of the beam. The beam may then be laid on the concrete floor slab and linked to the adjacent beams, so that the suspended ground floor surface and its supporting beams merely rest on the floor slab without necessarily being fixed to it.
Adjustable column mounting assembly
Railway arches are often provided with a concrete floor slab having a slight fall towards the sides or centre and/or one end of the arch in order to promote drainage of surface water, and which may also have an uneven surface. In such cases it may be inconvenient to insert shims or grout beneath each simple baseplate so as to equalise the heights of the stanchions, and it may also be difficult to make the stanchion perfectly vertical.
Moreover, it is desirable to arrange the stanchions as close as possible to the piers of the arch, and hence above the soakaway on either side of the arch. This may be problematic if the soakaway is a wide one.
A further illustrative embodiment will now be described providing a column mounting assembly which makes it possible to:

i) set out the base elements for a row of identical stanchions and fix them to the floor slab, irrespective of the inclination of the slab and without the use of grout or shims; and then
ii) adjust the height of each central support to compensate for any overall fall in the floor slab, using a laser level to align the central supports so as to conform to a horizontal plane and thus equalise the heights of all of the stanchions when they are installed; and then
iii) mount each stanchion on its respective central support, with its vertical load being transferred to the floor slab or (where the stanchion is arranged above a wide soakaway) in whole or in part to the infill material in the soakaway; and then
iv) adjust the orientation (i.e. verticality) of the stanchion so as to support it vertically, using the floor slab to restrain it against tilting, without changing its overall height.

Referring to Figs. 90A - 93, a column mounting assembly comprises a base element 1050 together with an upper element, the upper element comprising the footplate 1030 which is attached to the lower end portion 1000' of the alternative stanchion as described above, and a ground-engaging element as further described below.
The base element 1050 is a unitary cast iron component defining a flat baseplate with a plurality of ribs and bosses. The ribs stiffen the base element so that it acts as a cantilever to transfer (either in whole or in part) the vertical load on the column as well as non-vertical (e.g. horizontal and rotational) forces imposed on its overhang portion 1057 to its fixing portion 1058 and thus to the floor slab to which it is attached. It will be noted that the length and width of the base element are many times larger than its height (which may be for example only a few centimetres) so that it has a relatively low vertical profile, with the ribs tapering down as shown towards its fixing portion 1058 so that it can be fixed to a floor surface without forming an obstruction.
Each of the bosses defines a threaded hole which extends through the baseplate. The largest boss is located at the extreme end of the overhang portion with two medium diameter bosses spaced apart on either side of it The third medium diameter boss is spaced apart from the largest boss and aligned with it along the longitudinal axis of the base element.
A small region within a railway arch is depicted in which the edge 7" of the floor (the upwardly facing support surface 7' of the concrete floor slab 7) is separated from the vertical surface 4 of the pier 3 (defining one side of the arch) by a relatively wide soakaway 10". The upper layer of the ground 16 within the soakaway comprises an angular infill material, such as coarse crushed aggregate or railway track ballast, the ground surface 16' lying adjacent the support surface 7'. An angular infill material is preferred over the round pebbles commonly used for this application because it has comparable permeability but better stability and tends to knit together so as to transfer a compressive load to the lower layers of the ground 16" beneath.
The ground-engaging element 1070 comprises a flat pre-cast concrete slab with a steel plate 1071 set into its upper surface to distribute the point load from the load transfer elements. The slab 1070 is placed on or in the ground 16 in the soakaway, with a small amount of the infill material being removed as required so that the slab lies just below floor level as shown. It will be noted that the length L₂ of the slab 1070, as well as its width W₂, are both many times greater than its height.
The fixing portion 1058 of the base element 1050 is bolted directly to the surface 7' of the floor slab (irrespective of its inclination) using ordinary expanding bolts 1061 or any other convenient fixing system, so that its overhang portion 1057 extends above the ground surface 16' beyond the edge 7" of the support surface 7' and directly above the ground-engaging element 1070 as shown. Oversized fixing holes 1060 provide a large margin of error in drilling the initial holes in the floor slab, the first bolts 1061 being installed with oversized washers 1062 having eccentric fixing holes.
The slab may extend beneath one or both pairs of small bosses, in which case small support screws are inserted into whichever pair lies closest to the edge of the slab so that they prevent it from tilting under the load applied by the load transfer elements.
A centre screw is then inserted into the threaded bore of the central boss, and advanced downwardly until its lower end abuts against the plate 1071. (In this specification a "screw" means any screw threaded element.) A wrench is then engaged with the drive portion and the screw is torqued so that its lower portion forms a load transfer element 1064' which extends between the overhang portion and the ground-engaging element and acts in compression to urge the ground-engaging element downwardly away from the overhang portion. The base element 1050 acts as a cantilever to react the applied force (via bolts 1061) against the mass of the floor slab 7. By using a torque wrench (i.e. a wrench with a facility for measuring the applied torque) a known proof load can thus be applied to the ground-engaging element, the applied torque corresponding to the downward force applied to the ground-engaging element (which is selected as a known proportion of the designed load on the stanchion) and hence indicating the loadbearing capacity of the infill material and the ground beneath. The centre screw can then be backed off until it just touches the ground-engaging element 1070. Alternatively it can be left in a fully or partially torqued condition, in which case the upward load on the base element may eventually be relieved or reversed by compaction of the infill material under the applied load from the stanchion.
Two side screws are then inserted into the bosses with a front screw being inserted into the front boss, and all three screws are advanced downwardly in a similar way to the centre screw until they engage the plate 1071. The lower portion of each screw thus forms an axially adjustable load transfer element which functions to transfer the vertical load on the stanchion (either in part or in whole) from the overhang portion to the ground-engaging element. To the extent that the vertical load is not fully transferred to the ground-engaging element 1070, the base element 1050 acts as a cantilever to transfer the remainder of the load to the floor slab 7 with the bolts 1061 acting in tension to restrain the fixing portion 1058.
After installation, the upper portion 1064", 1065", 1066" of each respective screw forms a threaded stud which projects upwardly from the overhang portion 1057, the threaded studs providing a mounting structure for mounting the footplate 1030 and lower end portion 1000' of the stanchion on the overhang portion and thus connecting the stanchion in fixed relation to the base element and to the support surface 7'. A large, female threaded central nut 1068 defining a part-spherical, upwardly facing mounting surface 1068' is received on the upper portion 1064" of the centre screw of each mounting assembly. A laser level (not shown) is set up at one end of the railway arch and adjusted so that it emits a horizontal laser beam parallel with the longitudinal axis of the arch and passing directly above each of the aligned central supports. (Alternatively, a rotary level can be set up in the middle of the floor so as to project a reference plane over the whole floor.)
All of the central nuts are aligned at the same horizontal level. As long as all the stanchions are identical, having fixing holes in exactly the same position, this quick and simple procedure ensures that the stanchions will all be at exactly the same vertical height once they are installed. This makes it possible to install a perfectly level mezzanine floor without further measurement or adjustment, simply by fixing the beams at predetermined positions on the stanchions.
With the central nut 1068 in the correct position on the centre screw, a lower nut 1069 is then threaded onto each of the three smaller screws and positioned below the level of the central nut as best seen in Fig. 92B. The mounting assembly is now ready to receive the stanchion.
Referring to Fig. 93, the footplate 1030 of the stanchion is pivotably mounted on the central support with the bevelled lower edge of the central hole being pivotably supported on the upwardly facing mounting surface 1068', and the upper nuts 1069' are screwed down until they engage the upper surface of the footplate 1030. Since there are only three lateral supports, the lower nut 1069 on the front stud 1066" is also screwed up to engage the lower surface of the footplate; with all three upper nuts 1069' and the lower nut 1069 on the front stud in position, the footplate is thus clamped in a horizontal plane so as to support the column in a vertical orientation and restrain it against tilting, with non-vertical forces (e.g. horizontal displacement of the column or rotation of the column tending to tilt it about its base) being transferred by the base element to the support surface 7' and reacted against the mass of the floor slab 7.
The column is tilted in the longitudinal direction of the arch (side-to-side) by adjusting the two corresponding side-to-side lateral supports (each lateral support comprising the stud 1065" and the corresponding pair of nuts 1069, 1069'); and then in a separate step, is tilted front-to-back so as to bring it parallel with the surface 4 by adjusting the front lateral support (comprising stud 1066" and nuts 1069, 1069') until the correct vertical orientation is achieved.
The column is thus supported above the ground surface 16' beyond the edge 7" of the support surface 7' with the greater part of its load being borne by the central support 1064", 1068 which extends between the upper element 1030 and the overhang portion 1057 of the base element.
Instead of a concrete slab 1070 with an integral steel plate 1071, an ordinary concrete building block, a length of heavy steel channel or angle, a piece of suitably durable timber or any other convenient object can be used as the ground-engaging element. Preferably the material used is rigid and resistant to corrosion under the moist conditions in the soakaway when installed in a railway arch as illustrated.
Where a stanchion is installed above the end of the soakaway at the extreme end of a railway arch, there may not be enough room to lay a concrete block or the like beneath the base element so that it projects to an equal extent on either side, so that a short ground-engaging element such as a building block may tilt under uneven loading. In this situation the ground-engaging element may be arranged to extend between the bases of two adjacent stanchions, so that the respective load transfer elements apply pressure at each end. A common concrete lintel (perhaps 50mm or 80mm in thickness), such as used in supporting the brickwork above a wide window of a house, may be used for this purpose; preferably, the lintel is arranged upside-down relative to its normal orientation, so that its tensile reinforcement wires are closer to its upper surface.
In alternative embodiments, the or each load transfer element may comprise one or more parts, such as a lever, an articulated mechanism or the like, which need not act in compression.
It is possible for the load transfer elements to be adjusted after the column is installed and under load, for example, so as to compensate for slight movement of the ground. The or each load transfer element may also comprise or cooperate with a resilient element which transfers the column load resiliently to the ground. The incorporation of a resilient element compensates for relative movement between the base element and the ground-engaging element so as to keep the load on the base element fairly constant, effectively isolating the columns from small ground movements.
In yet further embodiments, the column can be mounted by means of conventional mounting structure (e.g. bolted) on the overhang portion, and part of its load may be transferred to the ground engaging element by means of a load transfer element which need not form part of the mounting structure. It is also possible for the base element to be hinged or the like so that, for example, horizontal forces are transferred to the floor slab (so that the column base is fixed in translation), but rotational forces are not reacted (so that the column is free to tilt), with the column being braced by separate horizontal struts or beams, tension wires or the like. In yet further embodiments, rather than providing a load transfer element, the mounting structure could comprise for example a collar arranged as an overhang portion which is welded to the base element, with the column being slidingly received in the collar so that the lower end of the column rests directly on the ground-engaging element. Alternatively for example, the column may be mounted on the ground-engaging element, and may be provided with a bracket which engages the base element so as to react non-vertical forces via the base element against the floor slab.
Instead of being welded to the stanchion as shown, the upper element may alternatively comprise a plate or other body portion adapted to be pivotably mounted on the central support, with a bracket to which the lower end portion of the stanchion may be bolted. If preferred, the lateral supports may be adapted to engage a separate part from the upper element, or even to engage the stanchion directly. Of course, any of the various stanchions disclosed herein may be used with the mounting assembly.
Where the mounting assembly of the first embodiment is installed in a railway arch with a narrow soakaway, the base element 1050 may be used as a pure cantilever to transfer the whole of the vertical load from the stanchion to the floor slab, so that no ground-engaging element is required. Alternatively, the soakaway may be absent, in which case the flat baseplate 1051 of the overhang portion rests directly on the floor slab and transfers the vertical load vertically downwardly to its upper surface 7'.
The novel mounting assembly is particularly suitable for use with columns which are lightly or moderately loaded, for example, supporting a load of less than about 25 tonnes or so, although of course it could also be used with heavier columns designed for much higher loads.

Flexible frame elements

Each flexible frame element may comprise a continuous, flexible metal or plastics section or profile (i.e. an elongate element with a uniform cross-sectional profile), such as an I-beam, a top-hat section, a square or rectangular hollow section, or the like, which has sufficient resistance to axial compression that it is capable of flexing to conform to the curvature of the soffit without collapsing axially under load. Alternatively, it may comprise a plurality of rigid, non-compressible portions joined in series by hinge portions. The latter arrangement is preferred since each hinge portion may then be arranged to prevent the formation of a reflex angle on the inner side of the frame element, i.e. the side facing inwardly into the interior space of the arch. (If a non-jointed, continuous, flexible, e.g plastics, profile were used, then it would need to have sufficient flexibility to bend outwardly to conform to the curvature of the soffit at its minimum radius. If the same profile were used on another arch with a much larger radius, then its flexibility could give rise to a risk of local buckling followed by catastrophic inward collapse of the arch lining, e.g. vertically downwardly at the crown. A hinged frame element, i.e. comprising rigid sections joined by hinge portions, would be usable in both arches as long as the hinges were arranged to substantially prevent the formation of a reflex angle.)
The rigid portions and hinge portions may comprise integral parts of a unitary length of material, in which case the frame element may be manufactured at relatively low cost (conveniently in mild steel by laser cutting) and may be suitable for one-time installation or, with care, for re-use for a limited number of times. Alternatively, a fully re-usable element may be assembled from individual, jointed sections. Long frame elements may also be cut to make shorter elements, and short lengths may be joined together to make longer elements.
Referring to Figs. 14B - 17, a first flexible frame element 70 comprises a unitary length of rolled mild steel "top hat" section, having a central, U-shaped recess portion with a pair of oppositely directed lateral flanges 71, in which the central, U-shaped portion is divided by means of a laser cutter to define a flexible series of rigid portions 72 joined end-to-end by the flanges 71, which are left intact so that they form a plastically reformable hinge portion 73 adjacent each cut. (Each rigid portion is "rigid" in the sense that it resists buckling under axial compression, although if desired it may admit of slight deflection in order to more closely conform to the curvature of the soffit It is also possible for each rigid portion to be slightly curved rather than straight as shown.)
The laser cutter produces cut lines of minimal thickness, so that the adjacent cut surfaces 74 which define the ends of each respective pair of rigid portion remain substantially in abutment to limit the range of pivotal movement at each hinge portion 73 to define a maximum angle θ of about 180° between the respective adjacent rigid portions on the inner side of the frame element, i.e. the side which faces away from the soffit. This substantially prevents the formation of a reflex angle on the inner side of the frame element, which ensures that the arched configuration of the frame element cannot fail by localised buckling inwardly and downwardly away from the soffit. The maximum angle θ of 180° also allows two frame elements 70 to form a rigid straight-line configuration when they are bound together flange-to-flange for dispatch from the factory, which makes them easy to handle prior to installation. Moreover, it allows adjacent rigid sections 72 to be vertically aligned along each stanchion below the spring line in their installed position.
Of course, rather than laser cutting, the frame element could be manufactured by conventional cutting or stamping/pressing. In order to bring the cut surfaces 74 into closer abutment, part of the rear wall 75 or side walls 76 which together comprise the central, U-shaped portion can be pressed or stretched to form a slight bulge at each cut line prior to cutting and then pressed back again afterwards, or local portions of the cut surfaces can simply be pressed together after cutting. It is also possible to press localised areas of adjacent rigid portions together so as to define a maximum angle θ of less than 180°.
The central, U-shaped recess portion of the frame element is adapted to be slidingly received in the central, U-shaped recess portion of the first stanchion 40 during assembly so that once the frame element 70 reaches its installed position, in which the rear wall 75 is pressingly engaged against the soffit (adjacent each hinge portion) for at least some or, preferably, most or all of the length of the frame element, it can be bolted directly to the upper part of the first stanchion 40 as shown in Fig. 14C, with the flanges 71 lying against the flanges 41 of the stanchion.
Each pair of adjacent rigid portions 72 are pivotable during installation about their respective hinge portion 73 through a range of movement which is preferably limited in the outward direction by the abutment of the cut surfaces 74 and both restrained and limited in the inward direction by a plastic deformation element as further described below, so as to define an obtuse angle θ between them on the inner side of the frame element This permanent flexibility allows the frame element 70 to be raised into its installed position beneath the soffit 5 so that, once it contacts the soffit, it may be urged against the soffit so as to conform to its upward and inward curvature, defining a self-supporting arched configuration which transfers the load of the frame element to its respective first and second ends 77, which in turn are supported by the respective stanchions 40 extending upwardly from the ground on either side of the arch. Once in its installed position, the frame element 70 does not need to be supported at any point other than at its respective ends 77, although it may be further rigidified and stabilised in the longitudinal direction of the arch by the attachment of bracing struts and/or panels between adjacent frame elements as further described below.
The rigid portions 72 are independent of each other so that they can adopt a different angle at each hinge portion 73, enabling the frame element 70 to conform to the curvature of any soffit, irrespective of its shape, and also to adopt a more acute angle at the spring line where it departs from the stanchion.
Since each flexible frame element 70 in accordance with the first embodiment is stabilised and rigidified by compressive hoop stress and by frictional contact with the soffit, it is unnecessary and undesirable to provide means for locking each of its rigid portions 72 in fixed angular or rotational relationship to the next This permanent flexibility simplifies the frame element and also makes it easy to remove it and re-use it, as well as enabling it to conform to the curvature of the soffit as it is installed. The frame element of the first embodiment is thus only suitable for use in contact with an existing, arched soffit, and would not provide the rigidity required for a freestanding structure, independent of an existing arch or tunnel.
In alternative embodiments, described below under the heading "locking the joints", means are provided whereby, after the frame element has been pressingly urged against the soffit so as to conform flexibly to the curvature of the soffit as described above, the hinge portions may then be locked, following which the frame element may be slightly lowered so as to mechanically decouple it from the soffit while still retaining its arched configuration.
The flanges 71 form the inner side of the first frame element 70 which faces away from the soffit in the installed position, and each flange is provided with panel attachment structure (panel attachment means) comprising two rows of panel fixing holes 78, which are adapted to receive self-tapping screws and are arranged in diagonal pairs as shown so as to cooperate with the corresponding fixing holes in the panel flanges according to the Vernier principle as discussed above with reference to the first stanchion.
Each rigid portion is provided with support attachment means (stanchion attachment structure) comprising two rows of stanchion fixing holes 79 in each of its side walls 76, which are adapted to cooperate with the corresponding front fixing holes 48, 49 of the first stanchion forming an adjustable attachment system according to the Vernier principle as described above. This enables the first and second ends 77 to be slidingly adjusted in very small increments relative to the stanchions during installation so as to bring the rear wall 75 pressingly into abutment with the soffit, and then to be attached to the stanchion 40 so as to support the frame element 70 in the installed position.
Since stanchion fixing holes 79 are provided in each rigid portion, rather than just at the ends 77, the frame element 70 may be divided by cutting it with an angle grinder or the like so as to form two shorter frame elements, and the cut ends of each frame element may thereafter be attached to the support means.
Preferably, the cutting (and joining of shorter elements, as described below) is done in the centre of a rigid portion, so that for reliability the hinge portions are always formed at the factory and not by the user. Indicia 80 are provided on the outer surface of the rear wall 75 of each rigid portion 72 to indicate the correct cut line.
The rear wall 75 of each rigid portion 72 is also provided with means for releasably attaching the frame element to an installation tool, comprising two oppositely directed pairs of keyhole slots 81, 81'. When the rigid portion is cut by the user, one pair of slots 81 or 81' is left on each cut half, which then forms the end 77 of the frame element for attachment to the tool. In the example of Fig. 16A, the end 77 of the frame element terminates at a position corresponding to one of the cut lines, proving a terminal rigid portion 72' half the length of the others, which is attached to the tool during installation. Each frame element is supplied from the factory with one such half length terminal rigid portion 72' at each end, so that the frame element can either be cut to length or used as supplied.
It is important to ensure that the frame element is able to bend at each respective hinge portion 73 as it engages the soffit, so as to avoid straight portions which depart from the curvature of the soffit
One way of achieving this would be to resiliently bias each pair of adjacent rigid portions away from a straight line configuration, i.e. towards an inwardly bent configuration. However, to facilitate easy handling and transportation, it is preferable for each frame element to be biased towards (or supplied in) a straight line configuration in its rest position.
In order to achieve both of these objectives, preferably each hinge portion is provided with means which readily permits a first, small degree of bending inwardly into the arch, but which resists further bending until a substantially greater torque is applied to the joint. This means that as the frame element is progressively bent into its installed configuration (such as during attachment to the installation tools), as each hinge portion reaches its first extent of bending, it begins to transfer torque to the rigid portions on either side, so that all of the hinge portions are bent to the first, small extent, before the applied torque increases to the extent necessary to bend any of them further. Since all of the hinge portions are thus placed in an initially bent configuration when they contact the soffit, they are more readily bent to a further extent necessary to bring all of the rigid portions into abutment at their ends with the soffit.
Of course, it is not essential for every one of the rigid portions to abut the soffit after installation, since the load on the framework will bring each frame element progressively into contact with the soffit at its outer ends, ensuring that it remains stable even as it flattens slightly at the crown to accommodate any slight settling or movement after installation.
Referring to Figs. 19A - 19D, rather than cutting completely through the central, U-shaped portion at each hinge portion, the cut is preferably interrupted to define a plastic deformation element 87 in the rear wall 75 which forms the outer side of the first frame element 70 in the installed position, attached to the respective rigid portions 72 at each end and adjacent and spaced apart from the respective hinge portion 73.
(For the avoidance of doubt, in this specification the term "plastic deformation element" means "plastically deformable element, and not "a deformation element made from plastics material"; whereas the term "plastics" or "plastics material" refers to polymer material. Preferably, the plastic deformation element is made integrally with the frame element, e.g. from mild steel.)
In the first frame element 70, the plastic deformation element 87 comprises a pattern of cuts (conveniently made by a laser cutter) similar to that used when forming the diamond shaped steel mesh commonly known as "expanded metal" or "expamet".
Each plastic deformation element is progressively plastically deformed by elongation during installation as the obtuse angle θ between the respective adjacent rigid portions reduces. The cut lines in the centre of the plastic deformation element are closer together than those at the ends, defining a weaker, initial deformation region 88 which is deformed to a first, minor extent as shown in Figs. 19A-19B by application of relatively little torque to the respective hinge portion. The remainder of the plastic deformation element is deformed to a second, relatively greater extent as shown in Figs. 19C - 19D, only by application of relatively greater torque.
In its maximally deformed condition (perhaps slightly beyond the position shown in Figs. 19C and 19D), the plastic deformation element 87 prevents further bending and so defines a minimum, limiting angle θ. Once deformed, the plastic deformation element 87 will also provide a degree of resistance to bending in the reverse direction, so that it tends to hold the flexible frame element in its arched configuration, which makes it easier to remove and re-install it without fatiguing the hinges.
In alternative embodiments, the plastic deformation element can be arranged as a crumple portion which is compressed as the angle θ reduces. It can also be a separate element, e.g. wrapped around the pivot pin of each discrete rigid portion of an articulated, re-usable flexible frame element, one embodiment of which will now be described.
Referring to Figs. 21B - 24D, a third, fully re-usable flexible frame element 110 comprises an articulated assembly of individual rigid portions 112 joined end-to-end by pivots 113.
Similarly to the first flexible frame element, each rigid portion 112 comprises a short length of galvanised or passivated zinc plated mild steel formed into an elongate "top hat" section comprising a rear wall 115 and two opposed side walls 116, which together form a central U-shaped portion, and two oppositely directed lateral flanges 111. The rear wall 115 forms the outer side of the frame element which engages the soffit, while the flanges 111 form the inner side of the frame element which faces away from the soffit in use. The end walls 114 of each rigid portion cooperate to form abutment surfaces which limit the obtuse angle θ formed between each pair of adjacent rigid portions on the inner side of the frame element to a maximum of 180° as shown in Fig. 24C.
Panel fixing holes 118 are provided in each of the flanges 111, while stanchion fixing holes 119 are provided in each side wall 116 so that the frame element can be attached to one of the stanchions 40 as already described above. Two oppositely directed pairs of keyhole slots 121, 121' are provided in each rear wall, and indicia 120 indicate the correct position at which the rigid section 112 may be cut to define two separate, half length terminal sections, each of which may subsequently be attached to the first installation tool and thereafter to one stanchion 40 as one end of a separate frame element Similarly to the first frame element, each third frame element 110 is supplied with two half length terminal rigid sections (not shown) so that it is ready for use.
The side walls 116 of each rigid portion 112 are joggled inwards to form an outer pair of hinge brackets 122 at one end of the rigid portion and an inner pair of hinge brackets 123 at the other. The rigid portions are assembled together at the factory by means of a steel rivet 124 which passes through the respective outer and inner hinge brackets to form a pivot pin about which the two sections can pivot The pivot pin 124 passes through a spacer 125 (made for example from plastics material) which maintains the separation between the inner pair of brackets 123 so as to rigidify the resulting pivot or hinge portion 113.
After assembly, the ends of the pivot pin or rivet 124 lie flush with or slightly inward of the side walls 116 as shown, so that the assembled frame element can be slidingly engaged in the stanchion 40 in the same way as the first frame element already described.
The rear wall 115 of each rigid portion 112 is cut at each end to define a bracket 126 which is bent inwardly towards the flanges 111. A resilient deformation element, comprising a helical steel tension spring 127, is attached between each pair of adjacent brackets 126 so that it extends between the two adjacent rigid portions 112 in spaced relation to the hinge 113. The spring is accommodated by a cutout in the rear wall so that it can be positioned as far as possible from the hinge portion 113.
As the adjacent rigid portions 112 pivot about the hinge 113 during installation (Fig. 24D), the spring 127 elongates proportionately to the applied torque, so that it transfers torque from one rigid portion to the next in a similar way to the plastic deformation elements already described, ensuring that each hinge portion is angled during installation.
Preferably, the spring 127 is arranged so that, in the 180° or rest condition of the respective hinge portion, its coils are almost or completely closed and it is only lightly engaged with the brackets 126, as shown in Fig. 24C. This means that relatively little torque is required to pivot the rigid portions 112 to a first, minor extent, before the spring more strongly resists further deformation until substantially greater torque is applied. Each resilient deformation element 127 thus biases the third frame element lightly towards a straight line configuration in its rest condition, as shown in Fig. 24C.
The tension spring 127 or hinge portion 113 or rigid portions 112 may be provided with an extension limiting arrangement (for example, a short steel cable or bar inside the spring, or a sleeve around the spring, or an arm which extends from one rigid portion to abut against the other) which defines a minimum, limiting angle θ and so prevents over-extension of the spring. Instead of a tension spring, the resilient deformation element might comprise a helical compression spring arranged between two abutting surfaces of the respective adjacent rigid portions 112 - for example, between the rear wall of one rigid portion and a projecting arm of the other rigid portion - in which case the compression spring will define a minimum, limiting angle θ at the point at which its coils are fully closed. A resilient, rubber or plastics spring could be used instead of or in addition to a coil spring. Alternatively, the resilient deformation element could comprise a leaf spring, or any other type of spring, such as a torsion spring arranged around the pivot pin or spacer so that its projecting ends engage the respective rigid portions 112. Of course, the articulated, third frame element 110 could also be made without resilient deformation portions.
Instead of resilient or plastic deformation portions, each separate pivot or integral hinge portion could include some other means providing a reaction force or resistance to pivotal movement - for example, a friction device arranged at the pivot.
Referring to Figs. 33C and 33D, each resilient deformation element could be formed by a plastics or rubber block instead of a spring. Fig. 33C shows a resilient deformation element 770 cut from an extruded section of resilient material, e.g. rubber, having a central hole 771 to receive the pivot, two wings 772 which engage the respective rigid portions of the frame element, and a stem 773 supporting a compressible top cap 774 which extends between the frame element and the soffit, so as to cushion the abutting ends of the rigid portions against small movements of the soffit The stem extends between the ends of the rigid portions of the frame element, which are recessed to accommodate it; it may resiliently bias them apart so as to initiate the angular deflection between the two sections in use.
Fig. 33D shows an alternative resilient deformation element 780 extruded from resilient plastics material and having insert portions 781 for insertion into apertures in the central wall of the U-shaped section of each respective rigid portion; a corrugated, resiliently extensible portion 782 which resists angular deformation at the joint; and a stem 783 which may be used to urge the rigid portions apart as installation commences, or to insulate them where welding is intended.
Of course, if preferred, the pivots 113 could be arranged to permit the user to divide the frame element and re-join it at each hinge. Preferably however the hinges are permanent and are made in the factory so as to avoid any risk of incorrect assembly, and the frame element is divided if required by cutting through a rigid portion where indicated (120).
The pivots 113 allow the third frame element to be installed, removed and re-installed as many times as necessary, so it can be re-used each time the framework is removed for renovation of the arch.
In contrast, where the first unitary frame element is made from mild steel or perhaps from aluminium, it must be treated with care so as to avoid repeatedly stressing its unitary hinge portions, which could result in metal fatigue and ultimately failure of the hinges. The relatively great length and small profile of each frame element may make it difficult to install it without repeated flexing; however, this difficulty is ameliorated by the presence of the deformation elements which limit angular displacement at each joint, and is preferably overcome by use of the novel installation tool, as further described below.
It is envisaged that articulated frame elements (assembled from separate sections) will be preferred for long term use in arches which are frequently inspected, whereas unitary frame elements (which can be manufactured at low cost, for example, by re-working a roll formed or pressed, top hat section with a production laser cutting machine) will be preferred in one-time installations which are not likely to be disturbed, or in situations where economy is more important
It is also envisaged that those using the novel system on a regular basis will keep a stock of frame elements and divide and re-join them as necessary for each job.
Referring to Figs. 25A and 25B, a jointing bar 130 comprises a rigid, U-shaped section having a rear wall 131 and two side walls 132, each side wall having a series of holes 133 which correspond to the fixing holes (79, 119) in the side walls of each rigid section of the first and third frame elements. Two frame elements may be joined end-to-end to form a longer frame element by arranging the jointing bar 130 inside the central, U-shaped portions of the respective, half-length terminal rigid sections of the two shorter frame elements so that they abut in the centre of the jointing bar, and bolting the two frame elements respectively to the jointing bar via the cooperating holes.

Shield

Referring to Figs. 27A - 30, a first, preferred shield 150 comprises an elongate profile extruded for example from high density polyethylene. A central, attachment portion 151 extends along its longitudinal axis L, flanked by two lateral water shedding portions 152, each having a front surface 153 which faces away from the soffit in use and an opposite, rear surface 154 which faces towards the soffit in use.
The attachment portion 151 forms a resilient clip structure having ribs 155 which engage in corresponding grooves in the stanchion and frame element to attach the shield, either to the rear surface of the stanchion (Fig.29), or to an outer side of the frame element (Fig. 30) so that the shield stays in place as the frame element is raised into an installed position beneath the soffit, The clip also defines grooves 156, which receive the ribs 155 of a second length of shield, the clip structures deforming resiliently so that the two lengths can be clipped together in nested relation, such as at the overlap just above each stanchion.
The front surface 153 of each of the water shedding portions 152 includes an outer zone 162 having a plurality of water guiding structures 157 which extend in parallel with the longitudinal axis L so that they face towards the rear, water shedding surface of the adjacent panel in use. Each structure comprises a group of fins with narrow tips 158. The fins extend away from the surface 153 and curve slightly away from the attachment portion, defining an incurved portion 159 and a plurality of crevices 160, all of which tend to trap water droplets so as to encourage them to travel longitudinally along the water guiding structure while preventing them from travelling laterally across the front surface 153 towards the attachment portion.
The outer edge portions 161 of the water shedding portions curve back towards the soffit so that the outer zones 162 are urged away from the soffit and into contact with the rear surface of the panel. The fins are most effective near the crown, where the shield is almost horizontal, so that any water droplets that run onto the downwardly facing front surface of the shield are likely to run or drip off the narrow tips 158 of the fins onto the rear surface of the panel, which channels them down towards the ground.
A pair of first and second inner zones 163, 164 are arranged between each outer zone and the attachment portion. After extrusion, the inner zones 163, 164 are flat as shown in Fig. 27A. The extrusion is then passed between a pair of mating, heated rollers which impress a pattern of corrugations 165, 166 forming oblique water guiding structures into each of the inner zones. In the first inner zones 163, the corrugations 165 extend obliquely downwardly and outwardly away from the attachment portion as shown, while in the second inner zone 164, the corrugations 166 are reversed so as to extend obliquely upwardly and outwardly as shown.
The oblique corrugations become increasingly effective as the shield becomes progressively more steeply angled towards the vertical. In the position shown, any water droplets reaching the first inner zone 163 are guided outwardly away from the attachment portion by the corrugations 165. Preferably, two lengths of shield are arranged, both in the orientation shown, with a short gap at the crown of the arch which is covered by a short capping extrusion (not shown), which may be a thin extrusion with downwardly extending edges. This makes it easy to remove and re-install the frame element without disturbing spinal cabling running along the crown between adjacent frame elements, with the capping extrusion being left behind on top of the cabling. However, if preferred, a single length of shield can be attached along the whole length of the frame element It will be appreciated that the other end of the shield will then be in the upside-down orientation to that shown, so that the directions of the corrugations 165, 166 are reversed. The corrugations 166 of the second inner zone 164 are then effective to guide any water droplets which reach that area, outwardly away from the attachment portion.
The central wall of the attachment portion has thick corrugations 168 which form a compressible structure 167, which is arranged in use between the flexible frame element and the soffit The soffit of a railway arch exhibits very small movements (in the order of 1mm - 2mm or so) as trains pass over it, and the corrugations provide sufficient stiffness to react the hoop stress against the soffit, yet are capable of collapsing so as to provide lost motion which cushions the frame element and mechanically decouples it from small movements of the soffit, Instead of corrugations, an inherently compressible material could be used, such as a foamed plastics material, an elastomer, or the like.
When the frame element 70 is raised into an installed position beneath the soffit 5 as shown in Fig. 40, the attachment portion of the shield is thus positioned between the rear wall of the frame element and the soffit. The compressible structure cushions the frame element 70 against the soffit 5, so that the shield is not damaged as the ends of each rigid section of the frame element press upwardly and outwardly against the soffit. The lateral water shedding portions are spread out on each side during installation of the panels 200 so that they are urged resiliently into engagement with the channelled rear surfaces of the panels as shown, providing a dry zone beneath the shield.
(For the avoidance of doubt, references in this specification to the frame element being engaged against or in contact with the soffit are to be construed as including this arrangement, in which a shield is interposed between the frame element and the soffit.)
Preferably, the shield material is supplied on a large diameter roll, so that as it is unrolled it naturally adopts a curved configuration which helps it to conform to the curvature of the frame element
It will be noted that the shields and panels do not rely on any compressive seal for their effectiveness, but rather on the respective downwardly and outwardly oriented water channelling surfaces which prevent water from travelling laterally towards the frame element This provides great tolerance between the various system elements so that the system remains effective, irrespective of the accuracy of installation or the curvature of the soffit. Of course, compressive seals or the like could be provided if preferred. The water shedding surfaces could also be micro-structured so as to define an energy barrier for droplets moving transversely, e.g. transitioning between the Wenzel state and the Cassie-Baxter state.
Alternative shield elements 149 and 140, each comprising a flexible plastics or elastomeric extrusion having lateral water shedding portions with longitudinal water guiding corrugations 143, and a central attachment portion comprising an adhesive strip145 for attachment to the frame element and a compressible structure 147 for absorbing movement between the frame element and the soffit, are shown respectively in the installed position at the crown of the arch in Figs. 39 and 40. In alternative embodiments, the shield could be made from other plastics material such as polyester, or from thin galvanized steel, aluminium or the like. In further alternative embodiments, the central attachment portion can have a rounded external surface which tends to deflect the frame element and shield away from any old fixings projecting from the soffit as the frame element is raised into position, and which also resiliently clips over the central recess portion of the frame element and cushions it against the soffit A springy cap made from galvanized steel or hard plastics material could also be clipped over the rear surface of the shield to deflect it away from old fixings projecting from the soffit, which are more preferably removed prior to installation.

Installation of flexible frame elements

The nominal required length L₁ for each flexible frame element can be calculated roughly, based on the width W of the arch according to the formula L₁ = ((πW)/2) + 2m, which resolves to L₁ = (1.57W) + 2m. This gives the correct length to span a semi-cylindrical soffit with a 1m overlap for fixing at each end.
Alternatively or additionally, a table can be supplied in which the columns are headed by representations of the arch configuration (egg-shaped, cylindrical, flattened, etc.), the rows correspond to the width of the arch, and the body of the table gives the required length of the flexible frame element for each combination.
In the example shown in Figs. 1 - 11, each unitary, flexible frame element 70 is about 10m in length, about 50mm deep (between its rear wall and its flanges) and about 110mm in width (between the outer edges of its flanges). It is relatively rigid in its width direction, but due to its length it is quite floppy in its depth direction, which presents a potential difficulty in transporting it and raising it into its installed position, several metres above ground level, while avoiding uncontrolled movements which could cause unnecessary flexing and weakening of its integral hinge portions.
Referring to Fig. 14D, this problem is avoided prior to installation by supplying the flexible frame elements 70 in pairs which are arranged front to front (flanges together) and banded together by plastics ties 178. Since each frame element is preferably constrained to form a maximum angle on its inner face (facing away from the soffit in use) of 180° at each joint, the two elements together thus form a substantially rigid, straight assembly in which they are easily handled and transported to the point of use without damaging them.
Referring to Figs. 3 - 7, each frame element 70 is then preferably installed by means of a pair of first installation tools 300, by which means each frame element 70 is easily raised into pressing engagement with the soffit and then secured in its installed position while avoiding any unnecessary flexing of its integral joints.
Referring particularly to Fig. 3, each first installation tool 300 comprises a releasable mounting mechanism 301 for mounting the tool for controlled movement towards the soffit; a frame element attachment mechanism (302, Fig. 5) for releasably attaching one end of the flexible frame element 70 to the tool; and a movement mechanism 303 for controlling the movement of the tool up and down towards and away from the soffit. In the embodiment shown, the releasable mounting mechanism 301 is adapted for releasably mounting the tool in sliding engagement with the flanges 41 of one of the stanchions 40, while the movement mechanism 303 comprises a mechanism for manually raising and lowering the tool up and down the stanchion.
In addition, each tool 300 preferably includes a separation adjustment mechanism 304 for moving the respective end of the attached frame element 70 towards and away from the respective stanchion 40; and a pivot mechanism 305 controlled by a releasable ratchet mechanism, which permits the frame element 70 to be raised from a substantially horizontal orientation to a substantially vertical orientation after attachment to the tool while restraining the frame element 70 against downward movement.
The various features of the first tool 300 are described in more detail in due course.
Once all the stanchions 40 are in place and the bracing struts 60 and bracing cables 67 have been installed, each of the two installation tools 300 is mounted on the base of a respective one of a first pair of stanchions 40 on opposite sides of the arch, the ratchet is released by pulling the detent ring 423, and the pivot mechanism 305 is pivoted in whichever direction offers more room, so that each respective frame element attachment mechanism 302 extends horizontally or, preferably, slightly downwardly towards the floor of the arch. The separation adjustment mechanism 304 is adjusted by means of its removable handle 396 to provide a gap between each end of the frame element and the respective stanchion 40, which accommodates the ends of the shield 149 as the frame element is raised as further described below.
A first pair of frame elements 70 are then placed on the ground and separated by cutting the ties 178. One frame element 70 is then attached at a first one of its ends 77 to the attachment mechanism 302 of a first one of the tools, so that it extends along the ground away from the respective stanchion 40 (Fig. 3).
The installer then walks with the second end 77 of the frame element in a wide arc towards the second tool, so that the frame element is progressively bent into an arched configuration while it lies on the ground, and attaches the second end 77 to the attachment mechanism 302 of the second tool 300 as shown in Fig. 58. Bending at each hinge portion is controlled by the respective plastic deformation elements as described above.
Once the two ends 77 of the frame element 70 are attached to the two respective tools 300, the midsection of the frame element is raised a short distance off the ground and supported on building blocks 11 or the like. A length of shield material 149 is then cut from the roll and fitted over the outer (i.e. the soffit-engaging) face of the frame element 70, so that it extends along the whole length of the curved frame element between its two ends. (Fig. 4.)
The frame element 70 is then raised to a substantially vertical plane as shown in Fig. 5, while the attachment mechanism 302 of each tool pivots about its pivot mechanism 305. The ratchet mechanism cooperates with the pivot mechanism 305 to allow upward movement while preventing the frame element from falling back downwards in either direction, and cooperates with a safety detent bolt (further described below) to automatically lock the pivot mechanism 305 of each tool when the frame element 70 reaches its vertical position.
This makes it relatively straightforward for two people to raise the flexible frame element 70 by pushing it upwards, one at each end, or even for a single person to raise it by pushing it initially as close to the middle as they can reach, then closer to one end, relying on the two ratchets to hold it up once it reaches a more upright position. The maximum 180° angle θ between adjacent rigid portions 72 prevents the frame element 70 from bending outwardly to contact the stanchions 40, so that it settles into a stable, fairly even, arched configuration in which it is safely supported in a vertical plane, clear of the stanchions, as shown in Fig. 54.
Alternatively, for installation by one person, the midsection of the frame element 70 can first be raised as high as possible off the ground and supported on a short freestanding ladder. A rope or plumb-bob cord 12 is then passed through the two centre keyhole slots 81, 81' in the rear wall 75 of one rigid portion 72 nearest to the middle of the frame element 70, and the frame element is raised to the vertical position by pulling the rope or cord 12 in the longitudinal direction of the arch. This can also be accomplished without effort by passing the rope 12 through a block which is fixed between the upper ends of two distant stanchions, or by using two ropes passing through two blocks fixed respectively to the upper ends of two distant stanchions.
Of course, if preferred, each tool could also be adapted to provide a geared mechanism or the like for raising the frame element to an upright position, although the applied torque will then be substantial.
Once the frame element is locked in the vertical position by the detent bolts, with the shield 149 extending down between the frame element and the stanchion at each end, a handle 550, comprising a short steel tube with a threaded inner end and a hole in its outer end, is screwed into the left-hand (upward) drive socket 522' of the movement mechanism 303 of each tool. In the example shown, a short length of cord 13 is also attached to the hole in the outer end of each handle so that the handle can be operated from the ground against the restoring force of its return spring 535' (further described below). (Fig. 5.)
The two handles 550 are then operated (either simultaneously by two people or alternately by the same person) by pulling on the cords 13 to raise each tool 300 carrying the frame element 70 up the two stanchions 40, until the outer face of the rear wall 75 of the frame element (cushioned by the shield 149) contacts the soffit 5.
The ends of the shield material 149 attached to the frame element 70 are thus removed progressively from the gap between the frame element and the stanchion by the upward movement of the tools. They are then trimmed as necessary, and the upper end of the shield material 149 previously captured behind each stanchion 40 is led up beneath the shield material 149 on the frame element 70 as shown, so that the two lengths overlap to provide a water-shedding joint (Fig. 6.)
The removable handle 396 of each separation adjustment mechanism 304 is then operated to move each respective frame element attachment mechanism 302 carrying the respective end 77 of the frame element 70 outwardly, so that the central U-shaped portion of each end of the frame element is slidably engaged in the central U-shaped portion of the corresponding stanchion 40, with the flanges 71 of the frame element abutting against the flanges 41 of the stanchion, as shown in Fig. 60.
If necessary, each frame element 70 can now be adjusted for verticality by means of a plumb-bob 14 suspended on the cord 12 which is attached to the midpoint of the frame element A second cord 15 is stretched between the respective supporting columns 40 beneath the frame element. The position of the frame element is simply adjusted by pulling on the plumb-bob cord 12 in the required longitudinal direction of the arch until the plumb-bob 14 is in alignment with the bottom cord 15. (Fig. 6.)
The handles 550 are then operated again so as to raise the tools 300 and the frame element 70 slidingly upwardly relative to the stanchions 40, forcing the frame element pressingly upwardly and outwardly against the soffit 50 into its final, installed position. This upward movement induces a compressive hoop stress between the ends 77 of the frame element, forcing each rigid portion 72 of the frame element outwardly against the soffit 5 and sandwiching the shield 149 between the frame element and the soffit along its whole length while urging the upper ends of the stanchions outwardly against the piers.
Each end 77 of the frame element 70 is then attached by bolts 50 to the upper end of the stanchion 40 above the tool, as shown in Fig. 14C, so that the residual hoop stress is maintained by the stanchions acting in compression. Due to the adjustable attachment system already described, based on the Vernier principle, the frame element 70 is attachable in virtually any vertical position on the stanchion 40, and the degree of overlap is of little significance, so the system is very tolerant of errors in measurement or calculation. (Fig. 7.)
If the plumb-bob cord 12 was looped through the keyhole slots in the frame element, it can now be recovered by pulling on one end so as to be re-attached to the next frame element. Alternatively, it could be looped through a small wire or plastics widget (not shown) attached to the keyhole slots, so as to make it easier to recover.
The frame element attachment mechanism 302 of each tool is then detached from the frame element and the handle 550 is engaged in the right-hand (downward) drive socket and operated to bring the tool back down the stanchion 40, after which the mounting mechanism 301 is released and the tool is removed from the stanchion. The remaining frame elements 70 are then installed in the same way. In its installed position, each of the frame elements 70 is thus jammed up tightly against the brickwork of the soffit so that it conforms flexibly to the curvature of the soffit 5, forming a self supporting arched configuration in which it is supported only by the two stanchions 40 on opposite sides of the arch, while being rigidified and also restrained against movement in the longitudinal direction of the arch by frictional contact with the soffit. (Fig. 9.)
By use of the novel tool, the flexible frame element may thus be handled and installed simply and efficiently while avoiding unnecessary flexing of the joints. Moreover, there is very little need to work above ground level during installation of the framework. All that is required is a relatively short ladder which gives access to the upper end of each column for fixing the bracing struts and cables, overlapping the lengths of shield material, bolting the frame element to the column and operating the tool, which is preferably operable mostly from ground level as described. Thus (apart from a few bolts and a spanner) there is no need to carry tools or materials up or down the ladder.
Of course, the tools are equally suitable for use in installing the articulated frame elements 110.

Crown jointing element

Referring to Figs. 26A and 26B, a second jointing element 650 functions similarly to the jointing bar 130 (Figs. 25A - 25B), comprising attachment portions 651 for attachment to additional fixing holes (not shown) which are arranged in the side walls of the preferred flexible frame element 640 (Fig. 85) between its flanges and mounting holes 642. The attachment portions are arranged inside the frame element and spaced apart so as to define an open space communicating with a cutout 652. Raised wings 653 extend outwardly in use from a flat, central joining plate 654 in the longitudinal direction of the arch, and receive a mounting flange 661 of a cable tray 660 which functions in the same way as the struts 60, but also supports cabling running along the crown of the arch, which passes over the plate 654, as well as lighting fixtures which can be suspended from the tray. This cabling can branch off to pass through the cutout 652 and along the recess of the frame element, in the manner of a vertebral nervous system. Cabling can also pass along the frame element across the crown, in which case it is routed beneath the raised wings 653 and supported by bendable fingers 662 of the cable tray.
Advantageously, the cabling may be removed from the central recess of the frame element and left hanging from the frame elements on either side, following which the cable tray is disconnected and the frame element may be lowered (with the jointing element 650 in place). Any cabling passing over the central plate 654 is left in place, hanging from the crown of the arch between the two adjacent frame elements. Preferably, the shield is arranged in two lengths with a short gap at the crown, covered by a crown shield which extends above the spinal wiring. This enables the frame elements to be removed and replaced one by one without disconnecting the wiring.
Desirably, each frame element is divided into two halves, which are attached separately, one to each of the tools, and then brought together and joined in the middle of the floor with the jointing element 650. This makes them easier to handle and halves the amount of space required to bend them. The two tools may be synchronised as described below so as to ensure that all of the jointing elements 650 are aligned at the crown.
Desirably, bendable fingers can also be cut out from the frame element adjacent each hinge portion, which extend part-way across the central recess in spaced-apart relation so as to retain cabling in position, allowing the cabling to be inserted by twisting it between the fingers.

Joists

The stanchions may be used to support horizontal joists, providing a mezzanine floor, in which case the stanchions are dimensioned accordingly and the joists and floor are installed once the framework is in place and before the lining panels are attached, so that the floor provides a working platform which affords easy access to the whole of the soffit up to the crown.
Alternatively, where it is not intended to install a mezzanine floor, smaller stanchions are used, and lightweight temporary joists 181 may be releasably attached to the stanchions to support a temporary working platform giving access to the soffit
Referring to Fig. 9, for installation of a floor or working platform, a bracket 180 is preferably first bolted to the upper end of each stanchion 40. Each bracket 180 may comprise a flat plate which is inserted into the central U-shaped portion of the frame element 70 inside the stanchion 40 and is bolted through corresponding holes in the two abutting side walls 76, 46 (Fig. 14C). It may be installed at the same time as the frame element 70 is bolted to the stanchion, so that all three elements are fixed together simultaneously by the bolts 50. The bracket 180 may provide adjustable attachment holes, both for attachment of the bolts 50 and for attachment of the joist 181, so that the bracket 180 can be adjustably positioned on the stanchion 40 and/or the joist 181 can be adjustably positioned on the bracket 180. Alternatively, a two-part bracket can be used which provides positional adjustment between its parts.
Conveniently, each temporary joist 181 comprises a telescopic assembly comprising two hollow, box section or inverted, U-section or top-hat section aluminium end portions 182, in which an aluminium centre portion 183 is telescopically received. The centre portion 183 has slots 184, and the three parts are retained in sliding, adjustable relation by bolts 185 which pass through the slots. Each end portion 182 has a fixing hole 186 at its outer end, closer to its base than to its upper (horizontal) wall.
Each temporary joist 181 is first lifted at one end and slid over one of the brackets 180, which is received between the side walls of the joist so that the upper wall of the joist sits on the bracket, and then pivotably attached to the bracket by means of a bolt via the fixing hole 186. (Fig. 9.)
The other end of the joist is then raised off the ground (either by lifting it directly or, perhaps, by a modified attachment to the installation tool) and attached at its second end to the corresponding bracket 180 on the upper end of the opposite stanchion 40. The assembly telescopes to accommodate the changing length of the joist. By fixing two or three joists side by side and then laying boards or planks across them, a stable working platform or floor 187 is quickly created which affords easy access to the soffit up to the crown. (Fig. 10.)
The framework (comprising principally the flexible frame elements 70 and stanchions 40) can be used to support panels 200 or sheeting to form a waterproof lining, and can also be used either with or without a lining or shield elements to support lighting fixtures, pipework, racking and the like.

Modular flooring elements

Referring to Figs. 96 -101, a temporary floor or working platform may be quickly laid out on the regularly spaced, parallel joists 181 by interlocking a plurality of modular flooring elements 720. Each element comprises a generally planar loadbearing surface 721, formed for example from aluminium plate or glass reinforced plastics material. A plurality of parallel reinforcing struts 723 extend along a first horizontal axis X1 transverse to the joists between respective continuous inner transverse walls. Two end portions are defined between each transverse wall and a respective second discontinuous transverse wall 728 at which the loadbearing surface terminates, both transverse walls extending downwardly away from the plane of the loadbearing surface and below an upper surface 181' of the respective joist 181 to define a channel between them which receives the supporting joist in use.
Each end portion comprises two recess portions, one full width support portion 731 and two half width support portions 732. The corresponding half width support portions 732 of each adjacent pair of elements 720 are received as shown in the recess portion of an adjacent element 720, so that they lie between the respective support portions 731 and 732 of that element. Each element thus locks the two adjacent elements together, so as to form a continuous, safe working surface which cannot open up unexpectedly, and yet allows each element 720 to be lifted and replaced individually. Each recess portion extends along the first (length) axis X1 to define in use an aperture 733 between an inner edge of the recess portion and the respective opposed side 181" of an adjacent one of the joists. Each of the walls 728 is received in an aperture 733 as shown, so as to restrain each flooring element against movement along the first axis in the plane of the loadbearing surface by abutment of the wall 728 against the respective joist

Stub stanchions

After the joists and floor are installed, the flanges of each stanchion are clear from floor to spring line so that panels can be mounted on the stanchions all the way up, irrespective of whether the beams and floor remain in place. Preferably the beams are installed at least about 1.5m below the spring line (i.e. the line at which the curved soffit meets the vertical piers). This means that if it is intended to install a mezzanine floor, then there are two options after initial installation of the stanchions:

i) the flexible frame elements are installed first using the tools, and then the mezzanine floor is installed.
ii) the mezzanine floor is installed first, and then the tools are mounted on the portions of the stanchions projecting above the level of the floor, and the frame element is laid out on the mezzanine floor, and attached to the tools as before, then raised into a vertical position and installed in the same way as before, except that the tools will travel only a very short distance before the flexible frame element engages against the soffit.

In either case, the flexible frame elements can be removed again in the same way, without disturbing the mezzanine floor.
If it is intended to install the mezzanine floor higher than the critical level of about 1.5m below the spring line, then an alternative procedure can be adopted.
The stanchions and mezzanine floor are installed as before. Then a short, vertical, stub stanchion is attached by means of a bracket to each end region of each beam. The stub stanchion is at least about 1.5m in height and extends vertically up from the beam to meet the soffit at its upper end. So each stub stanchion is horizontally displaced from the pier by a distance determined by the angle of the soffit, the height of the mezzanine floor and the height of the stub stanchion. The tools are then mounted on the stub stanchions and the flexible frame elements are installed as before, with the flexible frame element being formed into an arched configuration while laid out on the mezzanine floor. The soffit is thus lined with an upper set of panels attached to the flanges of the flexible frame elements and of the stub stanchions, so that this upper set of panels terminate at their lower edges adjacent the mezzanine floor to define low side walls. The piers can be lined with a lower set of panels which are installed behind the floor and terminate at their upper edges at the upper ends of the main set of stanchions adjacent the soffit. Similar stub stanchions can also be set in from the edges of the floor for lining an arch in which the soffit extends up from floor level.
Corrugated sheets are arranged to intercept water falling from the soffit in the zone behind the stub stanchions and direct it down behind the lower set of panels.
Water dripping down the upper set of panels is guided, either into a gutter supported on the beams just behind the stub stanchions (the gutter having sloped edge portions that extend between the adjacent stub stanchions to intercept water falling from the lower edge of each panel), or onto the corrugated sheets which extend down behind the upper edges of the lower set of panels.
When the arch is due for inspection and maintenance, the mezzanine floor can remain in place while the panels are removed. Each panel can be removed individually from anywhere in the arch, with the mezzanine floor providing a working platform for repairing the brickwork behind. While the panels are removed, any wiring remains in place in the U-shaped channels provided by the frame elements and the stanchions (as do any sockets and light fittings attached to the flanges), which are preferably left in place unless the brickwork behind them has to be accessed. This makes it much easier to do regular inspections without disrupting the internal arrangements of the arch. If necessary, the flexible frame elements attached to the stub stanchions can be removed (and later re-installed) by reversing the installation procedure, without removing the mezzanine floor.

Finishing the crown

Where it is intended to install lining materials, preferably a crown shield 190 is now attached between the frame elements 70 along the crown line, with its edges lying beneath the shields 149 on the flanges 71 of the frame elements, so as to intercept water falling from the crown of the arch and channel it downwards onto the panels 200 on either side.
The crown shield 190 comprises a corrugated plastics sheet, the corrugations being arranged to run in the transverse (width) direction of the arch so that they channel water downwards along the curve of the soffit.
Preferably, a bracing strut 60 or 60' is also arranged between each pair of adjacent frame elements 70 at the crown, so as to additionally stabilise the frame elements in the longitudinal direction of the arch. (Where panels are to be attached to the frame elements, the panels will also provide stability.) Each bracing strut 60 is installed underneath the crown shield 190 along the crown line so as to support the centre of the crown shield, and the crown shield is optionally attached to the bracing strut by cable ties 191 passing through holes in its edges, beneath the protective shield 149, as shown in Fig. 10 and in cross-section in Fig. 39.
In a development, the bracing strut can be adapted to define a cable channel for retaining cables, pipework and the like running between the adjacent frame elements at the crown line, in which case the adjoining longitudinal panel edges can be spaced apart along the crown line to leave a space for the cabling, which is finished by a longitudinal cover strip.

Panels

Referring to Figs. 34A - 37C, a first panel 200 comprises a body portion 201 made from waterproof, rigid, closed cell foamed plastics material (e.g. polyurethane, polyisocyanurate or expanded polystyrene), which is bonded to a substantially flat, planar front board 202 with bevelled upper and lower longitudinal edges 203, 222, whose substantially flat front surface 204 faces inwardly into the arch in the installed position. The board 202 can be made from cementitious material, calcium silicate, polypropylene, polyethylene or other fairly rigid plastics material, fibreglass, powder coated sheet steel, compressed cellulose or mineral particles, or any other fairly rigid material which is adequately strong and resistant to damp and which presents an acceptable internal surface 204.
Two steel flanges 205 are bonded, one at each end of the panel. The outwardly extending portion of each flange 205 forms an attachment portion which is perforated with fixing holes and slots, which cooperate with the corresponding fixing holes in the respective flange of the stanchion 40 or frame element 70 according to the Vernier principle as discussed above, providing a positionally adjustable fixing system. The attachment portions of the flanges are wide enough in the longitudinal direction of the panel to tolerate substantial variations in the spacing of the stanchions 40 and frame elements 70, so that each panel may overlap the respective flange of the frame element or stanchion to a greater or lesser extent as illustrated for example in Figs. 39 and 40.
The front board 202 and flanges 205 can all be arranged in a mould before the body portion 201 is formed by injecting a pre-mixed plastics compound into the mould to bond the front board 202 and flanges 205 together.
The rear, water shedding surface 212 of the body portion 201 is divided into a plurality of channels which extend in parallel in the transverse direction of the panel to guide water falling from the soffit 5 or shields 149 onto the panel, downwardly from its upper edge 210 to its lower edge 211, while preventing it from travelling laterally beneath the shields 149. A lower wall 215 curves inwardly (away from the soffit) in the installed position of the panel to define an elongate recess 221. The lower wall 215 is so arranged that its outer surface and inner surface are both inclined downwardly, irrespective of the angle of inclination of the panel in its installed position. This ensures that water running down the water shedding surface 212 of the channel will always drip vertically downwardly from the tip of the lower wall 215. In order to prevent water from running laterally along the lower wall, each of the lands which separate the channels extends around the tip of the lower wall to provide a nose which always lies at the lowermost point of the lower wall 215 (cf. Figs. 37A, 37C).
The overall depth of the panel between each of its flanges 205 and the rear surface 220 of each of the lands is slightly less than the depth of the frame element 70 between its flanges 71 and its rear wall 75, so that the body portion 201 can be accommodated adjacent the soffit 5 in the space between the frame elements 70. This allows the whole lining to be arranged very close to the masonry of the arch, maximising the usable space within.
The rear, water shedding surface 212 of each channel terminates at its upper end in a shallow recess 223 which extends longitudinally for the whole length of the panel, proximate its upper edge 210 and generally horizontally in the installed position. Each land tapers at its upper end to meet a shallow, faceted hump which divides the floor of the recess 223 between each pair of adjacent channels. This ensures that water falling into the recess 223 will not travel laterally along it, but will rather be shed to one side or the other of each hump 224 and thus directed into the nearest channel. The upper wall 225 of the recess 223 extends to define an elongate protuberance 226.
Referring particularly to Figs. 37A - 37C, the attachment portions are attached by self-tapping screws respectively, either to the flanges of two adjacent stanchions or to the flanges of two adjacent flexible frame elements, so as to support the panel 200 in an installed position in which it is inclined downwardly from its upper edge 210 to its lower edge 211, with its rear, water shedding surface 212 facing in an outward direction towards the soffit 5 or the adjacent pier 3, 3', as illustrated for example in Fig. 40.
Preferably, installation commences with the bottom panels. Each panel is attached to the framework above the one below so that the flanges 205 of each panel abut the flanges of the stanchion or frame element adjacent the respective upper and lower bevelled longitudinal edges 203, 222 of the front boards 202.
The rear surface of each of the lands at the lower edge 211 of the panel is radiused about an axis defined by the bottom edges of the flanges 205, so that the second panel may be installed by inserting its lower edge 211 behind the upper edge 210 of the panel below, before rotating its respective upper edge 210 towards the soffit into its installed position, the radiused surface allowing it to clear the soffit at its lower edge as it rotates. Since the front board 202 of the upper panel then rests on the front board 202 of the lower panel, it is easy to support the upper panel during installation, and if preferred, it may be secured by means of only two fasteners, one at each end either at mid-height or near to its upper edge.
Referring to Fig. 37A, two panels 200 are shown in their installed positions, close to the crown line 8 of a wide arch with a gently curving, flattened soffit, with their respective front surfaces 204 substantially aligned and their respective rear, water shedding surfaces 212 both inclined downwardly at a shallow angle θ₃ of only 2° below a nominal horizontal line H. (In Figs. 37A - 37C, the upper panel 200 is denoted by the reference numeral 200' and the lower panel 200 by the reference numeral 200", purely to distinguish their relative positions.) The respective upper and lower walls 225, 215 of the two panels are so configured (as already described) that, even in this position, they interlock to shed water from the rear surface 212 of the upper panel 200' to the rear surface 212 of the lower panel 200", such that the respective rear surfaces 212 of the two panels form an effectively continuous water shedding surface. In this configuration it is impossible for water to travel up out of the interlocking joint thus produced between the panels.
Referring to Fig. 37B, the two panels may be attached at any point adjacent the soffit or piers so that they are inclined downwardly at different angles of inclination as shown, whilst their respective upper and lower walls 225, 215 still cooperate to shed water from the rear surface 212 of the upper panel 200' to the rear surface 212 of the lower panel 200". In the position shown in Fig. 37B, the rear, water shedding surface 212 of the upper panel 200' is inclined downwardly at a relatively shallow angle θ₃ of about 5° below a nominal horizontal line H, representing the position of the upper panel if it were attached, just above the spring line of an arch in which the soffit departs from the spring line at an exceptionally shallow angle. In the position shown in Fig. 37B, the obtuse angle θ₂ between the upper and lower panels is about 102°, while in the example of Fig. 37A, the corresponding angle θ₂ is about 177°, giving a range of angular variation between the two illustrated positions of about 75°.
Referring to Fig. 37C, the upper and lower walls 225, 215 are so configured that the two panels may also be installed one above the other on the stanchions adjacent the pier at one side of the arch, with their rear surfaces facing the internal surface 4 or 4' of the pier and their respective front surfaces 204 in vertical alignment as shown.
In order to facilitate attachment of the panels to the stanchions adjacent each pier so as to form a vertical wall, as well as to the frame elements around the soffit so as to form a curved ceiling, the front surface 204 of each panel is preferably flat and planar as shown; of course, if preferred, each panel could be curved for use exclusively beneath the soffit, The foamed plastics body portion 201 and lands provide a light weight, rigid structure which also thermally insulates the front surface 204, reducing condensation.
Rather than directing water into soakaways at floor level, the panels may be arranged to discharge water into gutters at the spring. Instead of self tapping screws, the respective flanges may be adapted if preferred to receive special fasteners, designed for example so that they require only a quarter turn to install or release them. Such adaptations will be within the purview of those skilled in the art.
In alternative embodiments, the front board 202 could simply be a thin layer or coating attached to the body portion 201. It is also possible to make the panel in a single, unitary piece, without either flanges or a front board. The two flanges could be combined into a single, embedded supporting structure, or they could be integral with the front board, so that the panel comprises a foamed body portion with a metal front skin integral with the attachment portions. The panel could also be formed in one piece, or with inserts or a separate front surface material, by structural reaction injection moulding, reaction injection moulding, blow moulding, twin sheet thermoforming, or any other suitable process.
Rather than being deep grooves moulded into the rear surface of the body portion as shown, the channels could be defined by shallow ribs or the like which are formed on the rear, water shedding surface; the body and attachment portions of the panel could then be made for example as a unitary plastics moulding, or from a single sheet of steel which is joggled at its top and bottom edges to form the upper and lower walls.
Of course, the rear, water shedding surface of the panel could also be formed without channels.
Referring to Fig. 37D, in an alternative embodiment, the lateral regions 750 of the panel adjacent the mounting portions 751 are formed with channels 752 which are arranged obliquely so as to run downwardly away from the lateral edge 753 of the panel and towards its lower edge 754; these slanted channels divert any stray water droplets away from the dry zone beneath the shield. In the main body of the panel, narrower lands 755 are formed with a chevron pattern of channels 756 which run obliquely downwardly and away from the centre line 757 of the land 755 towards the larger channel 758 on either side. The parallel channels 758 are aligned with the lateral edges 753 of the panel, which (like those of the foregoing embodiment) advantageously allow the panel to be cut along its transverse (top to bottom) direction between the lateral regions 750 to virtually any required length, so as to fit between the final pair of stanchions or frame elements. Any water falling onto the lands is diverted towards the main channel on the nearest side, which prevents lateral flow.
Each of the channels 752 and 756 may be relatively shallower at its upper end 752', 756' and relatively deeper at its lower end 752", 756", so that it functions to divert water towards its lower end, even when the panel is nearly horizontal.
In this embodiment, the mounting portions 751 are discontinuous, comprising a pair of tabs 751 at the lower edge of the panel and a corresponding pair at the upper edge (not shown). This leaves the flanges of the stanchion or frame element clear between the flanges, so that electrical boxes and the like can be attached directly to the flanges between the adjacent panels. The cosmetic covers (not shown) which cover the gaps between adjacent vertical sides of the panels are selectively provided with apertures to conform to the boxes.
In order to allow each panel 200 to be cut to length along its transverse dimension if required, a replacement mounting flange is formed from a single, folded sheet of mild or spring steel, having an attachment portion similar to that of the panel 200 which extends from a pair of resilient, spaced walls which are arranged to embrace the cut end of the panel 200.

Finishing the lining

Referring to Fig. 11, the panels 200 are attached to the flanges of the stanchions 40 and frame elements 70, starting from the floor and working up towards the crown between the joists in a continuous sequence, so that each panel is interlocked with the one below. The final set of panels are cut to length and then fitted with replacement flanges as described above before being attached between the rear pair of stanchions and frame elements on either side of the arch.
Once the final rows of full panels have been placed on either side of the crown, the remaining longitudinal gap at the crown can be filled by a row of panels cut to fit along their longitudinal axes, or with two rows of cut panels which meet at the crown, with the lands being cut away if necessary to accommodate the bracing strut. Alternatively, a gap can be left to accommodate cables and the like, in which case it is preferably covered by a removable cosmetic cover strip (not shown). Once lighting fixtures and other fittings are in place, the temporary joists can finally be removed.
After installation, each frame element 70 is kept dry by its shield 149, so that any water falling on the area above the frame element is diverted downwardly along the shield or sideways onto the rear, water shedding surfaces 212 of the overlapping panels 200, whose channels prevent water from running back beneath the protective shields. The shields 149 extend around the end stanchions to cover the corners of the rear wall 9 (as well as the front wall, which is not shown), so that the front and rear walls can be finished, either conventionally or by means of another set of panels 200 supported if required on vertical, top hat section brackets screwed to the walls or attached at their upper ends to the rearmost frame element 70, to provide a complete, waterproof lining.
By providing an upper fastener and a lower fastener on each side of each panel 200, which are attached to the respective flanges 71 of the frame elements 70 on either side, each panel 200 acts as a rigidifying element or cross-brace which prevents movement of the respective frame elements in the longitudinal direction of the arch. Once all the panels are in place, the lining forms an extremely stable structure. The panels can be removed one by one for inspection and maintenance of the masonry, and when a major inspection is necessary, the entire lining and framework can be removed and replaced by reversing the installation procedure.
Advantageously, the continuous U-shaped channels defined by the nested frame elements and stanchions and protected by the shields can be used as conduits to carry wiring and small diameter flexible pipework around the inside of the arch, while the flanges of the frame elements, stanchions and panels provide mounting points for sockets, lighting fixtures and the like. The gaps between adjacent panels at each frame element are preferably covered by cosmetic, plastics or metal cover strips (not shown) which provide access to the cabling beneath, the cover strips preferably being resiliently retained so that their outer edges are pressed outwardly against the inner surfaces 204 of the panels, providing an even finish at each joint which covers variations in spacing between the stanchions, frame elements and panels. Of course, if preferred, the panels could be arranged to abut at their vertical joints as well.
If preferred, the novel framework can be lined with ordinary corrugated sheets or any other suitable sheets or panels instead of the panels 200, in which case each edge of the corrugated sheet or panel will form an attachment portion which is placed over the flanges of the frame element or stanchion and then drilled or screwed through to fix it in position.

Releasable mounting mechanism

Referring to Figs. 41B and 43, the releasable mounting mechanism 301 of the first installation tool 300 is adapted to mount the tool as shown on the flanges of a stanchion, and is shown attached to a third stanchion 40' which is similar to the first stanchion 40, having flanges 41' with regularly spaced rectangular apertures 43' which are adapted to receive the projecting teeth 471 of the drive pinion 470 of the tool 300. The mechanism 301 comprises two pairs of waisted rollers 310 mounted in bearings on the ends of pivoted arms 312, 312'. The corresponding arms of each pair are linked by bars 314. In the engaged position, the backplate 306 of the tool body is spaced apart from the stanchion by fixed rollers 315. A screwthread rotatably mounted between the lower wall 318 and an inner wall 319 of the body of the tool is rotated by a handwheel 321. Links 323 pivotably connected between the traveller 322 and the lower arms 312 draw each respective pair of arms 312, 312' together, causing the rollers 310 to converge behind the flanges 41' so that the fixed rollers 315 are engaged against the external surfaces of the flanges as shown. The tool 300 is thus captured on the stanchion 40' so that it can move up and down but cannot be rotated or detached. The handwheel 321 is rotated in the opposite direction to dismount the tool.
The retractable rollers adapt to stanchions of different widths, so that the tool can be attached to larger stanchions intended to support a mezzanine floor, or to smaller stanchions where only a lining is to be installed.
A lateral adjustment mechanism may be provided to engage the side walls of the stanchion, which positively locates the tool and prevents the side walls of the stanchion from flexing inwardly (particularly where a light duty stanchion is used) in response to the forces exerted by the rollers 310. A pair of pivotably mounted adjustable arms with guide rollers are positioned between the sidewalls of the stanchion. In use, a handwheel is rotated to urge the guide rollers outwardly into abutment with the sidewalls of the stanchion.

Frame element attachment mechanism

The frame element attachment mechanism 302, separation adjustment mechanism 304 and pivot mechanism 305 which together form the upper part of the first tool 300 will now be described with reference to Figs. 53 - 60.
The frame element attachment mechanism 302 comprises a rigid, upstanding parallelepipedal mounting base 360 with rectangular sides and a relatively narrow front profile as seen in Fig. 53, which is adapted to be received into the central, U-shaped portion of the frame element 70 between its side walls 76 so that the flat, rear wall of the mounting base 360 abuts the rear wall 75 of the frame element The mounting base 360 is sufficiently narrow to allow it to be received in frame elements of various sizes, selected according to the size of the arch and the load that they are intended to carry.
A pair of threaded shafts with knobs 363 at their front ends extend through threaded bores in the mounting base 360 and terminate beyond its rear wall in round mushroom-shaped retaining studs. A fixed stud is attached to the rear wall in spaced relation to each retaining stud.
Referring also to Fig. 16A, the retaining studs and fixed studs respectively are spaced apart by a distance corresponding to the distance between each pair of keyhole slots 81, 81'.
In use, the separation adjustment mechanism 304 is operated by rotating the handle 396 to position the mounting base 360 in spaced relation from the stanchion 40, the ratchet mechanism (described below) is released, the mounting base is pivoted towards its initial, downwardly inclined position, and the knobs 363 are rotated to advance the retaining studs outwardly away from the rear wall.
The half-length terminal rigid portion 72' of the frame element 70 is then placed over the mounting base so that the retaining studs pass respectively through the round apertures 82 or 82' of the keyhole slots in its rear wall 75.
The frame element is then slid towards the bottom of the mounting base so that the neck portions 83 or 83' of the keyhole slots are captured beneath the retaining studs, until the round apertures 82 or 82' are aligned with the fixed studs. The retaining studs are then tightened by means of the knobs 363 to clamp the neck portions 83 or 83' of the keyhole slots to the rear wall of the mounting base, the fixed studs extending through the round apertures 82 or 82' to locate the frame element firmly in position. Once the frame element is securely mounted on the mounting base 360, it is raised to the vertical position as shown in Fig. 54.
When the frame element 70 has been attached to the stanchion 40, the retaining studs are slackened off and the mounting base 360 is retracted by operating the separation adjustment mechanism 304 so as to withdraw the fixed studs from the round apertures 82 or 82' of the keyhole slots. The tool is then lowered for a short distance until the retaining studs are aligned with the round apertures, before the mounting base is retracted again to withdraw it from the frame element 70, the retaining studs passing out via the apertures 82 or 82'. The tool can then be reversed down the stanchion and removed.
Referring to Fig. 16A, it will be noted that the neck portion 83 or 83' of each keyhole slot is slightly longer by a distance d₉ than the distance between the corresponding retaining stud and fixed stud. This permits the attachment mechanism to be used alternatively in a second tool which has a second, alternative movement mechanism.

Pivot mechanism and separation adjustment mechanism

The mounting base 360 is mounted for axial movement on the pivot mechanism 305, which is mounted for pivotal movement about a threaded shaft 390 which in turn forms part of the separation adjustment mechanism 304.
The shaft 390 is mounted for rotation in a fixed axial position between a small rear bearing 391 and a front bearing. The front bearing is pressed into a housing which extends from the rear face of the front casing of the tool. The splined distal end 395 of the shaft extends from the front of the tool to receive a removable rotary handle 396.
The pivot mechanism 305 comprises a pivot frame 380 whose movement is controlled by a combined detent and ratchet mechanism 400, further described below, the ratchet mechanism including a pair of front and rear ratchet plates 401, 402 and a front protection plate, all three plates being laminated together and fixed to the front end of the pivot frame 380 to form a unitary assembly. The assembled pivot frame 380 and plates are pivotably mounted on the shaft 390 on the rear shaft bearing 391, which is pressed into an annular housing 383 fixed to the rear endplate 384 of the pivot frame 380, and a front bearing 382 pressed into an axial bore in the front plates.
The external surface of the annular housing 383 is mounted in turn within a large rear bearing, which is received in a recess in a rear mounting plate 307 screwed to the upper end of the tool body. The shaft 390 is thus mounted at its rear end in two concentric, inner and outer bearings, and at its front end in two coaxial, axially spaced bearings, which allow the pivot frame 380 and the shaft 390 to rotate coaxially but independently of each other.
A guide groove 366 extends along each side of the mounting base 360, which receives a slide key 367 screwed to the upper edge of the pivot frame 380. The upper part of the mounting base forms an overhang at its rear end which can be extended axially from the pivot frame, over the top of the rear mounting plate 307, to engage the attached frame element slidingly with the stanchion as shown in Fig. 60. The overall length of the overhanging portion of the mounting base 360 is sufficient to allow it to be used with frame elements and stanchions of various depths, while providing enough clearance between the stanchion and the frame element in its fully retracted position (Fig. 54) to accommodate the end of the shield material 149 during installation.
The pivot frame 380 defines a slide channel which slidingly receives the rear support portion of the mounting base 360, which is slidably retained in the channel by a bottom key 369 in addition to the upper slide keys 367 so as to form a rigid assembly which resists twisting forces exerted by the frame element. The threaded shaft 390 engages in a threaded block 370 at the base of the support portion, to which the bottom key 369 is screwed, so that the mounting base 360 is driven axially along the pivot frame 380 by rotation of the handle 396 and shaft 390.

Detent and ratchet mechanism

The front casing is extended to form a detent housing 410 whose lower wall has a pair of transverse guide slots 419 which define abutment surfaces at their inner ends.
The detent assembly comprises a square bolt having a chamfered rear end 422 and a ring 423 at its front end, and a wedge. A spring 429 biases the chamfered end 422 of the bolt into engagement with a corresponding aperture 404 in the protection plate and ratchet plates 401, 402, locking the pivot frame 380 in its vertical position.
Referring particularly to Fig. 63, the edge of the front ratchet plate 401 defines an arcuate ratchet 405 which extends from the 180° or bottom dead centre position B for about 105° in a clockwise direction to its upper extremity A, and a smooth, arcuate surface 406 which extends from the bottom dead centre position B for about 105° in an anticlockwise direction to its upper extremity C. The edge of the rear ratchet plate 402 defines an oppositely directed arcuate ratchet 407 which extends from B to C, and a smooth, arcuate surface 408 which extends from B to A.
The front ratchet 405 is engaged by the pawl 441 of a right-hand pawl assembly 440, which is mounted behind the front casing on a pivot pin. The rear ratchet 407 is engaged by the corresponding pawl 441' of a corresponding, left-hand pawl assembly 440'. Each pawl assembly is controlled by a respective, right-hand or left-hand pawl control lever 460, 460' mounted respectively on a fixed pivot 434, 434'. The right-hand pawl assembly 440 comprises a flat plate which is fixed solidly in spaced relation to its pawl 441 by a short spacer. The corresponding pawl 441' and flat plate of the left-hand pawl assembly 440' are joined by a long spacer.
Each flat plate defines a thin, arcuate guide arm whose distal end is separated from the body of the plate, for example by laser cutting, to define a socket in which it is frictionally retained. During assembly, the guide arm is bent sideways out of the plane of the plate, and two identical helical compression springs 447, 448 (447'. 448') are fed onto it, followed by a spring steel retaining clip 456, 456'. The distal end of the guide arm is then pressed back into the socket, and the clip 456, 456' is forced over the plate to secure the joint.
Each control lever 460, 460' comprises an arcuate lower limb which extends around the front bearing housing 393, having at its lower end a flat plate 462, 462' with a slot which is interposed between the two springs on the respective guide arm so that the guide arm passes slidingly through the slot
The upper end of each control lever is cranked so that it extends fowards through a window in the front casing to terminate in a tab 464, 464' which extends upwardly through the respective guide slot 419 in the lower wall of the detent housing.
A tension spring 465 is arranged between the upper ends of the guide arms, which biases the two tabs towards a rest position in which they abut respectively against the abutment surfaces. In this position, the compressive force exerted against the plate 462 or 462' by each of the paired springs 447, 448 (447', 448') on the corresponding pawl assembly is equalised to urge the respective pawl 441 or 441' into engagement with its corresponding ratchet
The ratchet mechanism is released by pulling the ring 423, which retracts the bolt from the aperture 404 and advances the wedge so that it urges the tabs 464, 464' apart This urges the plates 462, 462' inwardly so as to bias the pawls 441, 441' out of engagement with the ratchets and into abutment with stop pins 436, 436'. (The inner springs 4.47, 447' provide lost motion which permits delayed disengagement of the pawls from the ratchets.) The mounting base 360 can then be rotated in either direction until it is angled obliquely downwardly towards the ground, ready to receive the frame element as shown.
The ring 423 is then released so that the chamfered end 422 of the bolt is urged against the front face of the protection plate. In this position of the bolt, the wedge is disengaged from between the tabs 464, 464' so that the tabs return to their rest position and the pawls are urged into engagement again with the ratchets.
As the mounting base 360 is rotated upwards towards the vertical position, the chamfered end of the bolt slides along the front face of the protection plate and one of the two pawls is deflected against the oblique surfaces of the teeth of the corresponding ratchet while the other pawl slides along the corresponding smooth surface 406 or 408. Once the mounting base reaches the vertical position, each of the pawls abuts against the radial surface of the last tooth of its respective ratchet, preventing further rotational movement in either direction, while the bolt engages in the aperture 404 to provide additional security against inadvertent release.
During disassembly of the framework, a cord may be tied between the rings 423 of the respective bolts of two corresponding installation tools arranged on opposite sides of the arch, so that by pulling on the cord, both pivot mechanisms can be released simultaneously to allow a frame element mounted between the tools to be lowered to the ground, preferably controlled by a rope attached to its uppermost point.

First movement mechanism

Referring to Figs. 44 - 45, the movement mechanism 303 of the first installation tool 300 comprises a drive pinion 470 having rounded teeth 471 which extend through a slot 357 in the backplate 306 of the tool body so as to engage the rectangular apertures 43 or 43' in the right-hand flange of the first stanchion 40 or third stanchion 40', forming a rack-and-pinion mechanism. (Both stanchions are symmetrical, with corresponding apertures in each flange, so that they can be cut to length and installed either way up.)
For clarity, the section of Fig. 45 is taken at X45 of Fig. 44 through the mechanism, but at X45' of Fig. 44 through the corresponding apertures of the backplate and the stanchion.
The drive pinion 470 provides a positive, infinitely adjustable, reversible drive both up and down the stanchion, and is driven by a worm 480 which engages a worm wheel 472. The worm prevents the tool from slipping back down the stanchion until it is driven in the reverse direction. The drive pinion 470 and worm wheel 472 are formed as a unitary component or solid assembly and mounted coaxially on a bearing 473, the bearing being mounted between spacers 474, 474' on a first shaft 475 which is supported in the side walls 351, 352 of the tool body.
The side walls 351, 352 are extended to form arcuate portions 353, 353', and a front cover 490 comprising a flat web 491 and two lateral, forwardly projecting arcuate flanges (of which the right-hand flange 492 can be seen in Fig. 45) is screwed to the front casing 308 of the tool between the arcuate portions 353, 353' of the sidewalls so that a slot is defined between each flange and the corresponding arcuate portion of the sidewall.
The worm 480 is fixed to a second shaft 481 (or formed integrally with it), which is mounted for rotation in a rear bearing 482, the rear bearing being pressed into a housing 483 on the backplate 306, which housing is cut away at its lower right hand edge to accommodate the teeth of the pinion. The forward end of the worm shaft 481 carries a small spur gear 484 (either keyed to the shaft 481 or cut integrally with it) and is supported at its extremity in a bearing 485, which is pressed into a housing 493 on the flat web 491 of the front cover and retained by a plate 494.
A third shaft 476 is mounted in parallel with the first shaft 475 between the side walls 351, 352, and carries a pair of ratchet wheels 500, 500' together with a right-hand (downward) drive lever 520 and a left-hand (upward) drive lever 520', each component being mounted on a bearing for rotation about the shaft 476, the left-hand components being retained axially in position by a spacer 477.
Each ratchet wheel is a unitary component or solid assembly comprising a circular ratchet 501, 501' and a bevel gear 502, 502', both parts being arranged coaxially on their respective bearing 503, both ratchets 501, 501' being arranged so that their teeth face upwards at the front of the tool.
An intermediate cluster gear assembly 504 comprising a spur gear and a bevel gear, both gears being formed as a unitary component or assembled solidly together, is mounted for rotation about a bearing on a fourth shaft 508 so that the spur gear engages the small spur gear 484 on the worm shaft 481, and the bevel gear engages the inwardly facing bevel gears 502, 502' of the two ratchet wheels 500, 500', which rotate together in opposite directions. The fourth shaft 508 is mounted non-rotatably in parallel with the worm shaft 481 between a mounting block 510 on the backplate 306 and a corresponding mounting block 495 on the flat web 491 of the front cover, and has a tubular structure 509 in its centre which provides a transverse aperture through which the third shaft 476 can pass and also functions as a spacer to separate the bearings of the two ratchet wheels.
Each drive lever 520, 520' comprises a flat, generally triangular plate 521' which extends through the respective slot defined between one flange 492 of the front cover and the corresponding arcuate portion 353, 353' of the side wall of the tool body, with a second, curved cover plate (not shown) being arranged to cover the gap between the left-hand side wall and drive lever. Each plate 521' has a drive socket 522, 522' at one corner, a spool and bearing assembly 530, 530' at its second corner, and a ratchet assembly 540, 540' at its third corner.
The right-hand drive lever 520 will now be described in detail, the corresponding parts of the left-hand drive lever 520' being similar. The drive socket has an internally threaded portion at its base, which is adapted to receive a corresponding external thread at the inner end of the tubular drive handle 550 (Figs. 5 - 7). This allows the drive handle to be screwed into the socket so that it can be operated safely from ground level by a cord 13 tied through a hole at its outer end.
The spool and bearing assembly comprises a narrow spool with a bevelled retaining flange. A small steel cord 534 (534') is attached at its upper end to the spool, and at its lower end to a tension spring 535 (535') which is fixed under tension to the tool body. As the respective lever is depressed to its fully actuated position (shown in dotted lines 520", Fig. 45), the steel cord 534 (534') is wound onto the spool, tensioning the spring 535 (535'), which returns the handle to its rest position as shown in Figs. 44 and 45 after each stroke. Downward movement of the lever is limited by abutment with an upper edge 354 of the front casing 308.
The drive lever plate is provided with a pair of fixed pivot pins, a small stop pin and a large stop pin 527. The ratchet assembly 540 comprises a drive pawl 541 (541') with a short tab extending from its proximal end, which is mounted on the pivot and biased into contact with the corresponding circular ratchet 501 (501') by a pawl control lever mounted on the second pivot The pawl control lever has an elongate limb and a short, cranked limb which defines an abutment surface 546 extending radially from its pivot axis. A tension spring is arranged between the distal end of the pawl control lever and a corresponding hole in the tab of the drive pawl.
The elongate limb of the pawl control lever is biased into abutment with the small stop pin by a torsion spring so that as the drive lever 520 is depressed, the elongate limb of the pawl control lever moves away from the ratchet 501 and the tension spring urges the drive pawl 541 into engagement with the ratchet As the drive lever 520 is returned to its rest position by the return spring 535, the abutment surface 546 of the pawl control lever contacts a fixed web 355 extending from the backplate 306, rotating the short limb until it abuts against the large stop pin 527 to define the rest position of the drive lever. In this position, the tension spring urges the drive pawl 541 out of engagement with the ratchet 501, as shown in Fig. 45. The tension spring provides lost motion, allowing delayed release of the drive pawl 541 from the ratchet.
To drive the tool 300 up the stanchion, the handle 550 is inserted in the left-hand (upward) drive socket 522' and repeatedly pulled down in a pumping action against the return force of the tension spring 535'. The corresponding right-hand drive lever 520 is biased to its rest position by the return spring 535 so that its drive pawl 541 is held in the disengaged position, allowing the right-hand ratchet wheel to rotate in the reverse direction as the left-hand ratchet wheel 500' is driven round by the corresponding left-hand ratchet mechanism. The gears transmit the drive force from the drive lever to the pinion wheel, providing an upward movement through approximately one aperture 43, 43' of the stanchion for every downward stroke of the handle. The tool is reversed down the stanchion by inserting the handle into the right-hand (downward) drive socket 522 and operating the right-hand drive lever in a similar way.
In the example illustrated, the apertures 43' of the third stanchion 40' are arranged at a pitch d₁₀ of about 33mm. In practice, it may be preferred to adapt the gear ratio to provide more rapid movement and less mechanical advantage.
In an alternative embodiment, the manually operated gear train may be replaced by a reversible electric motor arranged to rotate the drive pinion through suitable reduction gearing, which may also incorporate a worm gear so that the tool is safely supported at all times against inadvertent downward movement Such adaptations are within the purview of those skilled in the relevant art.
On sites without a mains electricity supply, two such motorised tools may then be powered by a small portable generator which also provides power for a drill and an angle grinder as well as a circular saw for cutting the panels.
Preferably, the motors of both of the tools are adapted to be controlled via extension leads or wireless transceivers from a common control box, so that both tools can be simultaneously advanced up or down their respective stanchions on either side of the arch while the operator observes the operation from a convenient position.
The movement mechanism of the tool can be any mechanism suitable for controlling the movement of the tool up and down towards and away from the soffit, and need not be adapted to drive the tool up and down. The releasable mounting mechanism of the tool can be any mechanism suitable for releasably mounting the tool for controlled movement towards the soffit
For example, instead of being adapted for mounting on a stanchion which forms part of the finished framework, the tool may be adapted to be mounted on the structural lining (e.g. concrete or cast iron segments) of a tunnel, or on a rack attached to the structural lining. Alternatively, the movement mechanism may incorporate a straight or curved rack which is releasably mounted at the side of an arch or tunnel by the releasable mounting mechanism so that the tool can move up and down on the rack.
The installation tool attachment means of the frame elements need not comprise apertures in the frame elements, and the frame element attachment mechanism of the tool can comprise any means suitable for attaching one end of the flexible frame element to the tool; for example, it could grip the flexible frame element externally, or could present an aperture into which the end of the flexible frame element is inserted.

Motorised movement mechanism

Referring to Figs. 75 - 76, in an alternative embodiment the tools are formed generally as described above, but the worm 480 and pinion 470 are driven by an electric motor 670 via a slipping clutch 671 and gear train 672 in place of the manually operated mechanism. The motors are powered via multi-core cables from a hub unit 680 supplied from a power source 690, e.g. a small portable generator, which communicates wirelessly with a portable remote control unit 700.
A revolution counter 673 is arranged to sense the position of the pinion and to transmit a corresponding value to a register 680, 680', one register for each respective tool. Two sensors S1, S2 are arranged to sense the presence or absence of the rectangular apertures of the rack, which data are compared with the output from the revolution counter to determine whether a fault condition exists (i.e. an aperture not correctly positioned with respect to the rotational position of the pinion). A fault condition could indicate that the tool has reached the top or bottom of the rack. Desirably, the bottom portion of the rack is blank, providing a predetermined reference point which is sensed by S1.
Button 701 commands both tools to descend until S1 registers a fault, then to stop and clear the registers 680, 680'. Light 702 indicates registers clear. Buttons 703, 704 command both tools to raise or descend simultaneously. While they do so, registers 680, 680' are continuously incremented or decremented and are continuously compared. If one register contains a value exceeding that of the other register by a threshold amount, the corresponding tool is halted until the other register has been incremented sufficiently, i.e the other tool has "caught up". Both tools thus move in horizontal alignment, which (if they start from the same horizontal position) ensures that the crown jointing elements of each frame element will be perfectly aligned at the crown.
Button 705 is a speed control. The remainder of the remote control unit is divided into a red half 706 and a blue half 707, corresponding to the similarly identified red tool 708 and blue tool 709. Each half has independent up/down buttons 710, 711 for moving the tool independently of the other tool, and (optionally) in/out buttons 712, 713 for controlling the separation adjustment mechanism, which may also be motorised. Lights 714, 715 indicate a fault condition.

Locking the joints

In some installations, particularly where it is necessary to comply with regulations prohibiting the application of stress to the masonry structure, it may be preferred to mechanically decouple each flexible frame element from the soffit in the installed position. This may be achieved by providing each hinge portion with locking structure (locking means), which may be any convenient arrangement of interengaging mechanical parts, which can be actuated when the frame element is in the installed position beneath the soffit to lock the angle between each respective pair of adjacent rigid portions. Preferably, the locking means of all of the hinge portions should be remotely operable from ground level in one operation.
Irrespective of the mechanism employed, it is important that the frame element having locking joints remains flexible during installation so that it can be urged pressingly against the soffit into the installed position in the same way as the permanently flexible frame elements described above, each hinge portion adapting independently of the others to the correct angle as it contacts the soffit. Once the frame element has flexibly conformed to the curvature of the soffit, the joints are locked in the arched configuration. Once the joint locking mechanism has been actuated, the frame element can then be lowered slightly (for example, by one or two centimetres) to separate it from the soffit before it is attached to the stanchions. (The term "installed position" is intended to embrace this small final positional adjustment, in which the frame element has already adopted and remains in the arched configuration.)
The locking means locks each joint substantially in its installed position so that little or no further movement is possible; this prevents distortion of the framework under load, ensuring that it remains separate from the soffit Where each joint must be moved through a small angle of rotation in order to engage the locking mechanism, the locking means may be actuated with the ends of the frame element positioned inwardly of the stanchions, so that when the separation adjustment mechanism is operated to move the ends of the frame element outwards into engagement with the stanchions, the outward movement is just sufficient to rigidify the locked joints. A similar technique may be adopted even with the weldable embodiment (which admits of substantially no angular movement after the joints are locked), so as to pre-stress the frame element prior to attachment of the lining panels; experience will dictate the optimal procedure depending on the size and geometry of the arch and the type of frame element selected.
Where a mezzanine floor is installed, the floor joists will act in tension to restrain the ends of each frame element, ensuring that the stanchions do not rest outwardly against the piers. Alternatively, the upper ends of the stanchions can be tied together by a rigidifying girder (not shown - which may also provide a gutter for receiving water discharged by the upper lining panels) extending along the length of the arch at each spring line, the two girders being tied together by tension elements at each end of the arch. Alternatively, a tension element can be arranged slightly above the level of the spring as a chord across each arched frame element, tying its ends together. Even where none of these arrangements is adopted, the dimensions and materials of the frame element may be selected so that once the joints are locked in the arched configuration, the frame element enjoys sufficient inherent rigidity that its supporting stanchions (if any) remain vertical under load and substantially no stress is imposed on the masonry, the entire framework thus standing independent of the masonry structure.

Fourth frame element

Referring to Figs. 114A - 130B, a fourth frame element 850 comprises a flexible series of rigid body sections 820 joined end-to-end by hinge portions 821. Each rigid body section comprises a unitary, galvanised steel "top-hat" profile defining a rear wall 115 provided with oppositely directed keyhole slots 121, 121' and indicia 120 marking the cut line; left- and right-hand side walls 116, 116' having stanchion fixing holes 119; and lateral flanges 111 having panel fixing holes 118, all of which features, being common (mutatis mutandis) to the third frame element 110 described above and the fifth and sixth frame elements described below, will not be described further.
The sidewalls 116, 116' are joggled inwards and radiused about the first pivot holes 824 at the first end of each rigid portion (Fig. 115) and supported by tabs 822 pressed into corresponding apertures in the rear wall 115. Each sidewall is perforated to define an array of radial slots 823 radiused through about 180° of rotation about the first pivot hole 824 and spaced apart, each from the next by an angle of θ₄ degrees of rotation.
At the second end of each rigid body section 820 (Figs. 116B and 117) the sidewalls 116, 116' are also joggled inwards, and each sidewall is perforated to define an array of fifteen apertures 825, 825' radiused about the second pivot hole 826 and spaced apart, each from the next by an angle of θ₅ degrees of rotation. Each array is arranged in two arcs, one radially inward of the other, with the radial centreline of each of the apertures of the inner arc bisecting the angle θ₅ between the radial centrelines of the two adjacent apertures of the outer arc, both arcs falling within the radial extent of the slots 823. Comparing Fig. 116B with Fig. 117, it will be noted that the two arrays are mutually angularly offset, so that the apertures 825 of the left-hand sidewall 116 are aligned mid-way between the corresponding apertures 825' of the right-hand sidewall 116'.
The radiused outer edge portion 827, 827' of each sidewall is divided into a plurality of tabs which are turned over (for example, by pressing in a dished tool) to form a scalloped rim which is radiused about the second pivot hole 826 and covers the apertures 825, 825'.
Two hooks 828 are pressed from the rear wall 115, and a recess 829 is formed in the lower edge of the left-hand sidewall 116 to accommodate the end of the torsion spring. A corresponding recess 829' is formed in the lower edge of the left-hand sidewall at the first end of the body section.
Referring to Figs. 118A - 118E, a cartridge frame 830 is pressed from steel plate to define two sidewalls 831, 831', each having a pivot hole 832, joined by a top wall 833 having two slots. A spring abutment 838 is pressed from the right-hand sidewall 831' to receive one end of the torsion spring, while a recess 839 is formed in the lower edge of the left-hand sidewall 831 to accommodate the other end of the torsion spring.
Each sidewall is perforated with an array of fifteen round holes 835, 835' arranged in two arcs in exactly the same pattern as the apertures 825, 825', at an angular spacing of θ₅ degrees of rotation about the pivot hole 832, the corresponding holes 835, 835' of each sidewall being aligned mid-way between those of the other.
In addition to the round holes 835, 835', each sidewall 831, 831' is provided with ten smaller holes 836 which are filled with plastics material in an injection moulding process so as to key the plastics moulding 837 to the frame 830, as shown in Figs. 119B and E. The moulding defines thirty bores, each of which communicates at one end with one of the holes 835, 835' and is closed at its opposite end by the opposite sidewall 831, 831'.
After moulding, the cartridge frame 830 containing the plastics moulding 837 is inserted slidingly into a receiving channel in a filling machine (not shown) and advanced along the channel until each of the thirty holes 835, 835' is aligned with a corresponding bore in the machine. Each bore of the machine contains a flat ended piston and communicates with two filling channels, one containing a magazine of hardened steel locking pins and the other containing a magazine of bias springs. Each piston is advanced so as to push one bias spring followed by one locking pin into the corresponding bore in the moulding 837.
A cartridge retaining clip 843 comprises a curved, pressed steel or moulded plastics shell having two parallel sidewalls 844 and an aperture 845 at its lower end. The cartridge frame 830, now containing a locking pin and a compressed locking spring in each of its thirty bores, is then advanced slidingly along the receiving channel until its sidewalls 831, 831' pass between the the sidewalls 844 of the clip, which is an interference fit over the cartridge frame, the clip restraining all thirty locking pins in their bores against the outward biasing force of the bias springs.
The fourth frame element is assembled by first inserting the sidewalls of the first end of a first rigid body section 820 between the sidewalls of the second end of a second rigid body section 820, so that the pivot holes 824, 826 of the two sections are aligned.
A pre-assembled cartridge frame 830 with its retaining clip 843 in position is then inserted between the sidewalls 116, 116' of the two rigid body sections 820 so that the hooks 828 of one body section pass through the slots in its top wall 833. The cartridge frame 830 is then slidingly displaced so that the projecting end of each hook 828 engages under its top wall 833 and the pivot holes 832 in the cartridge frame 830 move into alignment with the aligned pivot holes 824, 826 in the sidewalls 116, 116'.
A tubular spacer is then inserted into the centre of the torsion spring before both components are inserted together between the sidewalls 831, 831' of the cartridge frame 830; the first end of the torsion spring is received under the abutment 838 in the right-hand sidewall 831' of the cartridge frame, while its second, hooked end 847' is accommodated by the aligned recesses 839, 829'. 829. The assembled hinge portion 821 offers little resistance to a small initial rotation, but proportionately increasing resistance to further rotation as the spring is progressively deflected by abutment with the upper edge of the recess 829'. It is thus relatively easy to insert the rivet 848 through the aligned pivot holes 832, 824 and 826 and spacer with the two rigid portions in a straight line configuration, in which the rear walls 115 abut each other to prevent the formation of a reflex angle in the same way as the earlier embodiments.
The rivet is then closed to fasten all of the components together, so that the cartridge frame is rigidly fixed by the hooks 828 and the rivet 848 to the second end portion of the respective rigid section 820, with each hole 835, 835' and its corresponding bore containing a locking pin and bias spring being aligned with a corresponding aperture 825, 825' in the adjacent sidewall 116, 116'.
After assembly, the ends of the rivet are accommodated in the depth of the recesses formed by the joggled outer portions of the sidewalls 116, 116', so that the entire frame element can be mounted on the installation tool and slidingly accommodated in the stanchion before being fixed in the installed position in the same way as the third frame element.
The inner, first end portions of the sidewalls 116, 116' of one rigid body section 820 are accommodated between the sidewalls 844 of the retaining clip (positioned over the cartridge frame 830) and the outer, second end portions of the sidewalls 116, 116' of the adjacent rigid body section 820, so that the slots 823 lie between the locking pins (restrained by the clip 843) and the apertures 825, 825'. (Fig. 129.)
The angular spacing of the aligned holes 835, 835', locking pins and apertures 825, 825' is related to that of the slots 823 according to the Vernier principle described above by the formula θ₅ = θ₄ - (θ₄ / n) wherein n is a whole number, and the number of apertures 825, 825' in each array is preferably n or (n -1).
In the example shown, θ4 = 4.5°, n = 15 and θ5 = 4.2°, giving one coincidence between respective ones of the fifteen locking pins and twenty-one slots 823 in each of the two arrays of each hinge portion 821 for each increment of (θ₄ / n) = 0.3° of rotation. Each of the two arrays of fifteen locking pins thus provides three hundred discrete, equally spaced angular locking positions through a range of 90° of relative rotation of the two rigid sections about the pivot.
For any given angular position of the two rigid body sections 820, the two rigid body sections 820 must therefore be rotated through an angle of between 0° and 0.3° in either direction in order to bring one locking pin in each array of fifteen locking pins into alignment with a corresponding one of the apertures 823.
It will be appreciated that as well as providing very fine angular adjustment, this resiliently biased locking mechanism according to the Vernier principle also provides multiple redundancy and hence great reliability, and in practice (depending inter alia on manufacturing tolerances) more than one locking pin in each array may engage at the same time. In the example shown, the slots 823 of both sidewalls 116, 116' coincide, so that two locking pins (one in each array) may engage simultaneously.
Alternatively, the two arrays of slots 823 may be mutually angularly offset by ((θ₄ / n) /2) = 0.15° of rotation, providing a total of 600 locking positions through a 90° range, each defined by a single locking pin. Each joint may then be moved to the locked position by an average rotational displacement (being half the angular increment) between the two rigid body sections 820 of only (0.15 / 2) = 0.075°, which provides that each joint will lock substantially without any movement at all in its installed position against the soffit. Of course, only one array of abutment elements could be provided, which could be arranged in any suitable number and angular relation.
Installation of the fourth frame element 850 may be accomplished in the same way as described above with reference to the first, second and third frame elements, by first cutting it to length as necessary (and/or joining two or more lengths together using a jointing bar similar to that of Figs. 25A - B) and attaching it at either end to an installation tool 300. A thin, flexible cord 851 is passed through each respective aperture 845 of each of the cartridge retaining clips 843, with sufficient length being left at each end to reach the floor when the frame element is raised to the installed position.
The frame element is then raised to the vertical position before the two tools 300 are then raised up the stanchions to bring the frame element 850 and shield 149 into contact with the soffit 5, generating a hoop stress which urges the frame element pressingly against the soffit along the whole of its length. The fourth frame element thus flexibly conforms to the curvature of the soffit 5, irrespective of its dimensions and geometry, which defines its arched configuration in the installed position.
Depending on the installation procedure which is found by experience to be most effective, the separation adjustment mechanism of each tool may be adjusted to separate the ends of the frame element from the stanchions by a predetermined distance while the ends of the cord 851 are pulled sharply downwards, pulling each of the cartridge retaining clips 843 out of the frame element Each of the clips 843 slides down the cord 851 to the floor, and is then discarded. (Fig. 130B).
With the retaining clips removed, the thirty locking pins in each cartridge are now urged outwardly by their bias springs against the perforated sidewalls of the corresponding rigid body section 820. As the separation adjustment mechanism is operated to move each end of the frame element into engagement with the stanchion, at least one of the locking pins in each joint moves into alignment with a corresponding one of the the slots 823, and passes through the slot and through the corresponding aperture 825, 825' until its outer end abuts against the inner surface of the scalloped rim 827, 827', locking the joint The outward movement of the ends of the locked frame element slightly flattens it at the crown so that it is separated by a small distance from the soffit along all or most of its length, relieving the hoop stress from the soffit The frame element 850 is thus slightly pre-stressed and mechanically decoupled from the soffit, and can now be fixed to the stanchions in its installed position (Fig. 7), in which it functions substantially as a rigid, curved beam and transfers its applied loading through the stanchions to the floor without contacting the soffit. Alternatively, the joints can be locked with the ends of the frame element fully engaged with the stanchions, and/or the frame element can be lowered slightly before the fixing bolts 50 are inserted.
Instead of individually biased pins housed in a pre-assembled cartridge, the abutment elements could comprise any suitable individual components or parts of the same component, spaced apart by x degrees of rotation and operable to engage respective ones of a plurality of cooperating counterabutment surfaces. Preferably, the locking mechanism of each hinge portion is resiliently biased towards the locked condition so that it can be remotely operated by actuating a release mechanism, as exemplified by the embodiment described.

Fifth frame element

Referring to Figs. 131A - 142, a fifth frame element 860 comprises a plurality of rigid body sections 861 having a "top-hat" profile and joined by hinge portions 862. The sidewalls 116, 116' of each section are joggled inwards at the first end of the section (Fig. 131 A) and perforated to define first pivot holes 863 and second pivot holes 864, the end of each sidewall defining two arcuate portions, each radiused about the first pivot hole 863, which are joined by a radial abutment surface 865.
At the second end of each rigid body section 861 (Fig. 132A) the sidewalls 116, 116' are also joggled inwards and are perforated to define a pivot hole 868 and a slot 869, one end of the slot extending part way through the oblique (joggled) region of the sidewall. The end of each sidewall is cogged to define an arcuate rack 870 which is radiused about the pivot hole 868, and is provided with an outwardly bent abutment tab 871. As in the previous embodiments, the respective ends 867, 874 of the rear walls of each adjacent pair of rigid body sections 861 cooperate to form abutment surfaces which define the limiting 180° angle between the adjacent sections in the rest condition of the frame element.
Referring particularly to Figs. 136A - 137B, a latch assembly comprises a frame 880 having an end wall 881 with a slot 882; two side walls 883, each with a slot 884 terminating in a pivot hole 885; and two outwardly extending flanges 886. A hardened steel latch plate 890 defines a stem 891 provided with first and second holes 892, 893; an intermediate portion 894 which defines two shoulders 895; and an edge 896 opposite the stem, which extends between two wings 897.
The latch plate 890 is first inserted slantwise into the frame through one of the slots 884, and positioned with its stem 891 between the two side walls 883 and its two wings 897 extending respectively into the two slots 884. A compression spring is then fitted slidingly over the end of the stem 891 until it abuts against the shoulders 895, before the stem is advanced through the slot 882 until it projects from the end wall of the frame, compressing the spring between the end wall 881 and the shoulders 895.
A split pin 887 is then inserted through the first hole 892 in the projecting stem of the latch plate and spread slightly to retain it in position. The latch plate is then released so that the spring 898 biases its edge 896 towards the pivot hole 885, the latch plate being restrained in its retracted condition as shown in Fig. 142 by the split pin 887 which abuts the end wall 881 of the frame.
The first cluster gear 900 comprises a notched wheel fixed coaxially between two small spur gears. The second cluster gear 905 comprises a pair of large spur gears fixed coaxially between a pair of small spur gears. The inner spur gears engage the two small spur gears of the first cluster gear, while the outer spur gears engage the two arcuate racks 870 of the sidewalls 116, 116'.
Conveniently, both cluster gears are cast, stamped or moulded as unitary parts in a suitable metal or plastics material.
The fifth frame element is assembled as shown in Fig. 142, with the two flanges 886 of the pre-assembled latch frame 880 being inserted into the slots 869 in one body section 861 before a rivet 875 is inserted through the aligned pivot holes 863, 868, 885 and the first cluster gear 900, so that the latch frame is fixed in position at the second end of the respective body section. The second cluster gear is mounted on a second rivet 875 between the pivot holes 864 so that as the two rigid body sections 861 are rotated about the joint, the second cluster gear is driven in rotation by the racks 870, in turn driving the first cluster gear 900. The maximum range of rotation away from the rest position is limited by the abutment of the tabs 871 against the radial abutment surfaces 865, while a tension spring 877 is accommodated between the tabs 866, 872 and serves to transfer torque between the sections of the frame element during assembly as previously described.
In use, a cord is passed through the respective eye 888 of each respective split pin 887 in the same way as described above with reference to the fourth frame element, so that the split pins can all be pulled out together after the frame element has been engaged against the soffit in the installed position. Once each split pin is removed, the latch plate 890 is urged by the bias spring towards the notched wheel 901 so that as the wheel 901 rotates, the edge 896 engages with one of the notches, locking the wheel and thus (via the gear train 900, 905, 870) the rotation of the two body sections 861 about the hinge portion 862. The gear ratio (and the number of cluster gears, which may be more than two) are chosen so as to give the required number of angular locking positions of the joint
Similarly to the fourth frame element, engagement of the latch plate 890 with the gear train may be accomplished by outward movement of the ends of the frame element in the installed position.
When the frame element is to be removed (e.g. for maintenance of the arch), it is recovered by re-attaching the tools and lowered to the floor, following which each hinge portion may if required be unlocked by inserting a small hooked tool into the second hole 893 in the stem of the latch plate (which extends beyond the end wall 881 of the latch frame in the engaged position), and pulling the latch plate back out of engagement. A new split pin can then be inserted into the first hole 892, after which the installation procedure may be repeated, either in the same location or in a future installation in a different arch. The fifth frame element is thus indefinitely re-useable.
The embodiment described advantageously provides a high level of security against inadvertent release of any one of the locked latch plates. If preferred, a mechanism may be provided for locking and releasing all of the latch plates simultaneously; for example, each latch plate may be controlled by a sprung lever having a distal end which defines an aperture, the aperture being arranged in a rest position so that it is equidistant between, but misaligned with, two fixed apertures formed in tabs extending inwardly from the rear wall of the respective rigid section. A light stranded steel cord is passed along the entire length of the frame element via each rigid portion in turn and through the misaligned apertures, so that it loops down to the aperture in each lever. By pulling the cord at one or both ends, each looped portion may be straightened, urging the distal end of the respective lever into alignment with the fixed apertures on either side, and thus applying torque to each lever, which may be arranged, either to pull the respective latch plate out of engagement with the notched wheel, or to re-engage the latch plate in its locked position by relieving the biasing force of a second spring which normally overcomes the latch plate bias spring to hold the latch plate in the disengaged position.

Sixth frame element

Referring to Figs. 143A -156, a sixth frame element 910 comprises a plurality of rigid, mild steel "top-hat" profile body sections 911, similar to those of the foregoing embodiments, joined together by hinge portions 912 which are adapted to be locked in the installed position by simultaneous resistance welding.
Referring particularly to Figs. 143A-150A, the sidewalls 116, 116' of each body section are joggled inwards at the first end of the section to define two flat inner plates 913, 913', each plate being radiused at its end about an enlarged pivot hole 914 and rigidly supported by tabs 915 pressed into apertures in the rear wall 115. A recess 916 is formed in the lower edge of the righthand inner plate 913 to accommodate the hooked end of the torsion spring, while two abutment tabs 917 are bent downwardly at the first end 924 of the rear wall 115.
The sidewalls 116, 116' are also joggled inwards at the second end of the section to define two flat outer plates 918, 918'. which are spaced apart from the inner plates 913 of the adjacent body section 911 and are provided with pivot holes 919 of a smaller diameter than the enlarged pivot holes 914. The end of each outer plate 918, 918' is radiused about the pivot hole 919 and is cut away at its lower edge so that after assembly, the right-hand outer plate 918 is spaced apart in the 180° (rest) position (Fig. 150A) from the hooked end of the torsion spring.
Each of the outer plates 918, 918' is also provided with a pair of inwardly extending dimples 920, the two pairs of dimples being arranged in opposed relation with their respective opposed inner surfaces 920' spaced apart by a slightly smaller distance than the corresponding outer surfaces of the inner plates 913, 913', providing an interference fit on assembly. The inner end surface 920' of each of the dimples thus provides a sliding electrical contact point between the two adjacent body sections 911, with all four dimples remaining in sliding and pressing contact with the inner plates 913, 913' through a range of over 90° of rotation between the two body sections.
A pair of mounting tabs 921 with rectangular holes 922 are pressed from the rear wall 115 slightly inwardly from its second end 923, which end is cut back slightly from the centre line of the corresponding pivot holes, so that after assembly the end 923 is spaced apart from the first end 924 of the rear wall of the adjacent body section in the 180° (rest) position, as best seen in Fig. 150A.
A plastics insulator block 930 is moulded to define a raised, rectangular portion adapted to fit in the recess defined in the rear wall 115 of the respective body section 911 by the pressed mounting tabs 921, which are received respectively in slots of the block. As the block 930 is pushed into position, locking tabs enter the rectangular holes 922 in the mounting tabs 921, which locks the block to the body section.
A tubular spacer (which may be made from metal or plastics material) is then inserted through the centre of the steel torsion spring 940, and both components are positioned in alignment with the enlarged pivot holes 914 between the inner plates 913, 913' so that the hooked end 941 of the spring is received in the recess 916.
An insulating plastics bushing is then inserted inwardly through each of the enlarged pivot holes 914 so that its inner end extends for a short distance into the respective end of the spacer, while its collar abuts the outer face of the respective inner plate 913, 913'.
With the insulator blocks 930, spacers, springs 940 and bushings in position, the frame element is assembled by sliding the inner plates 913, 913' of each respective body section 911 between the outer plates 918, 918' of the adjacent body section 911, so that the collars are respectively received loosely in the gaps between the inner and outer plates 913, 918 and 913', 918', and the two body sections 911 abut one another only at the dimples 920.
Similarly to the previously described embodiments, the torsion spring requires only minimal pre-load to engage its second end 942 behind the rear face of the insulator block 930 as shown in Fig. 150A, which electrically isolates the spring from the body section on which the block is mounted.
With the respective pivot holes 914, 919 in alignment, the steel rivet 938 is then passed through a Belleville washer 939 and then through the pivot holes 919 and bushings, which insulate the rivet and the outer plates 918, 918' of one respective body section (which are electrically in contact with one another) from the inner plates 913, 913' of the other respective body section, which is electrically in contact with the torsion spring. A second Belleville washer is passed over the hollow end of the rivet before it is closed, compressing both washers against the outer plates 918, 918'.
In the rest position (Fig. 150A) the electrically insulating plastics block 930 abuts against the tabs 917 to define the maximum (180°) angle between the two body sections.
The two body sections 911 are thus electrically isolated from one another except at the dimples 920, each of which defines a localised electrical pathway between the respective adjacent rigid portions, so that all of the adjacent pairs of rigid portions may be welded together simultaneously in series at each dimple by passing an electric current through the entire frame element from one end to the other, the magnitude and duration of the current being determined in accordance with known principles of resistance welding. The two Belleville washers 939 urge the two outer plates 918, 918' together, providing a constant compressive force between the inner surfaces 920' of the four dimples 920 and the inner plates 913, 913' throughout the welding operation.
Referring particularly to Fig. 153, an insulator shroud 950 comprises a short plastics moulding having a "top-hat" profile and dimensioned so that the sidewalls 116, 116' of a body section 911 of the sixth frame element may be snugly received between its sidewalls with the flanges 111 of the body section overlying the flanges of the shroud. Tabs retain the shroud firmly in position.
Apertures in the rear wall of the shroud provide clearance for the studs 364, 365 to be inserted through the keyhole slots 121, 121' when the body portion is engaged by the installation tool.
The frame element attachment mechanism 302' of the installation tool 300 is preferably adapted to electrically isolate the frame element 910 attached to the tool while providing a convenient attachment point for the welding cable 946.
The mounting base 360' is covered by an insulating jacket 960, while its rear wall (also insulated by the jacket 960) is recessed to accommodate a heavy brass plate 961 integral with the fixed studs 365. A heavy conductor with an insulating jacket also extends through the mounting base from the plate 961 and is threaded at its exposed end to form a stud 968. A heavy brass retaining plate 969 is screwed onto the stud and insulated from the mounting base by the jacket 960. The stud 968 is adapted to receive the ring terminal 947 on the end of the welding cable 946, which is captured by a threaded knob 970. When the studs are engaged with the half-length terminal body section 911' of the frame element 910, the body section 911' is electrically connected to the stud 968 via the plate 961, which is clamped firmly to its rear wall 115, but is electrically isolated from the rest of the tool. Although each retaining stud 364 contacts the body section 911', it is isolated from the rest of the tool and so no current flows through it during the welding operation, which avoids any risk of damage to its threaded shaft.
The shroud 950 is adapted to fit slidingly within the stanchion 40"', which is substantially the same as the first stanchion 40. In use, the stanchions are first erected as described above with reference to Figs. 1 and 2. Before attaching each end of the frame element 910 to one of the tools 300, a shroud 950 is first clipped to the half-length terminal body portion 911', and two shrouds are clipped end-to-end (one on either side of the central cut line 120) to each of the last two or three full length body portions 911 which will overlap the stanchion 40"' in the installed position.
The terminal body portion 911' is then engaged by the frame element attachment mechanism 302' and the shield material 149' is attached in the same way as the foregoing embodiments. The shield material 149' is electrically nonconductive (or has a nonconductive and heat resistant inner surface, such as a layer of woven glass fabric) and is resistant to the momentary localised heat of the welding operation. It may be made for example from a heat resistant plastics material. The frame element 910 is then raised into the vertical position until it engages pressingly against the soffit, and the separation adjustment mechanism of each tool is operated to engage the frame element fully with the stanchion, from which it is insulated by the shroud 950, the tools applying hoop stress so that lit conforms flexibly to the curvature of the soffit to define its final, arched configuration (Figs. 3 - 6).
Once in position, a resistance welding current source is connected via cables 946 between the studs 968 of the two tools, and a current is passed through the entire frame element so as to weld each pair of body sections together in series at the dimples 920 (Fig. 153). The current source may be adapted to regulate the voltage and other welding parameters (whether manually or automatically under the control of resistance sensing means) according to the number of joints in the frame element.
After welding, the frame element may be lowered very slightly in order to relieve the hoop stress from the soffit before it is bolted to the stanchions with the shrouds still in position, the bolts passing through the apertures in the shroud sidewalls. In practice it may be preferred to weld the frame element with the end portions disengaged from the stanchions, so that the separation adjustment mechanism may then be operated to pre-stress and rigidify the frame element as its two ends are moved outwards into their final, fixed position. Where this technique is adopted it may not be necessary to use the shrouds.

Removal and re-installation

Referring to Figs. 155 and 156, in order to facilitate the subsequent removal and re-installation of a permanently rigidified frame element (for example, the fourth frame element or the sixth frame element), a flexible jointing bar 980 may be used to join two equal lengths of frame element so that it forms a permanently flexible joint which lies at the crown of the arch in the installed position.
The jointing bar 980 comprises two rigid, U-shaped portions 981 joined by a central pivot 984. The parallel sidewalls 982 of each rigid portion have fixing holes 983 which coincide with the stanchion fixing holes 119 in the sidewalls of the frame element, so that the ends of the jointing bar may be inserted respectively into the central U-shaped portions of two terminal half-length rigid sections of the frame element which are then bolted to the jointing bar, one on either side of the central pivot 984.
In the embodiment shown, the pivot 984 is insulated and the maximum 180° angle between the two rigid portions in the rest position (which may be less than 180° if preferred) is defined by an insulating plastics abutment block 930 similar to that of the sixth frame element, which also receives one end of the torsion spring 985, while an insulated, flexible, braided conductor 986 bridges the two rigid portions 981. The jointing bar is therefore suitable for use with the sixth frame element, wherein the welding current passes through the conductor 986 and not through the pivot, so that the pivot remains permanently flexible and is not damaged during welding.
The jointing bar allows the permanently locked frame element to fold in the middle so that it is more easily removed and re-installed, such as when the arch is stripped for inspection, but (since it is the only hinge in the frame element) it does not permit the frame element to move into contact with the soffit under load. The frame element may be further rigidified in use by abutment of the two rigid portions 981 in the maximum 180° position (which they readily adopt since the jointing bar is arranged at the crown where the arched configuration tends to flatten), and/or by the support provided by a mezzanine floor or other means which restrains the upper ends of the stanchions against outward movement.
As the locked frame element is detached from the stanchions and begins to fold at the pivot 984, it will assume the shape of a gothic arch as its ends move inwards away from the piers. In order to facilitate this movement and make the locked frame element easier to remove, the frame element attachment mechanism 302" of the installation tool 300 may be further adapted as shown in Fig. 156 by arranging the mounting base 360" as an upper half 990 and a lower half 991, which are joined by two pins 992, 993. When the front pin 993 is removed, the upper half 990 together with the attached frame element can pivot about the rear pin 992 through a small angle θ₆, so that as the separation adjustment mechanism is operated to withdraw the frame element from the stanchion, the ends of the frame element can adopt a slight upward and outward inclination as the frame element folds.
The rear pin 992 can also be removable so that the entire upper half 990 of the frame element attachment mechanism can be detached from the rest of the tool. This may be convenient in re-attaching the frame element attachment mechanism to an installed frame element preparatory to removing the frame element, wherein the upper half 990 is first engaged with the frame element and the remainder of the tool is then brought into position before the pin 992 is inserted to lock the upper and lower halves 990, 991 together. Similarly, it may make it easier to detach the tool from the frame element after installation, by first separating the two halves 990, 991 and then detaching the upper half 990 from the frame element.
Of course, the adapted tool is equally suitable for use with the non-locking embodiments disclosed earlier.

Summary

In summary, a preferred embodiment provides a plurality of elongate, flexible frame elements, each protected by a flexible, waterproof shield and engaged frictionally against the curved soffit by hoop stress applied at either end, preferably by a pair of installation tools mounted on stanchions. Each tool preferably includes a pivoting ratchet which allows the flexible frame element to be formed into an arched shape on the ground and then raised into a vertical plane prior to installation. Each frame element may comprise a unitary "top-hat" profile with deformable hinges, each hinge having an associated deformation structure which distributes bending forces evenly during installation. The frame elements may be fixed to the stanchions to support them at either end in their installed position, providing a self-supporting, arched framework which relies upon the masonry soffit for its shape and stability. Alternatively, each frame element may comprise joints which are remotely locked in the installed position, allowing the frame element to be decoupled from the soffit. The framework can be installed without specialist access equipment, and the stanchions may be used to support a temporary mezzanine floor made from modular, interlocking panels which provides access to the soffit for installation of cooperating, flat lining panels, each panel preferably comprising a foamed plastics body with downwardly directed channels and interlocking upper and lower edges which cooperate to form an angularly adjustable joint
Instead of the baseplates first described, a single steel beam or the like could alternatively be fixed horizontally along the base of each pier, each stanchion being attached at its base to the beam; alternatively, each pair of stanchions may be attached, one at either end of a beam arranged transversely across the floor of the arch, so that a suspended floor may be laid across the beams, in which case the beams and stanchions need not be bolted to the floor. The entire installation may then be accomplished without the use of a drill or nail gun.
Instead of or additionally to the use of shield material, each frame element and/or each column might be made with an integral shield portion which diverts water downwards to the ground and/or to the panels on either side. In the frame elements, the shield portion might also form the integral, plastically deformable hinge portions, which may then be located on the outer side of the frame element: For example, each frame element might comprise a flat strip of steel, aluminium or plastics material arranged adjacent the soffit, with a series of short, rigid box sections extending (integrally or in fixed relation) from its inwardly facing surface. The box sections may be flanged and may provide attachment means (e.g., screw holes or channels) for receiving the lining sheets or panels, which may have flanges as illustrated or alternatively for example may simply slot into the channels. The ends of the box sections may be spaced apart by a sufficient distance that they abut to define a minimum obtuse angle at each hinge portion. The whole frame element (or just the strip) may be galvanised, and the strip may be bent along each edge, inwardly into the arch and/or outwardly towards the soffit, so as to prevent water from running back along its inner surface. Such an integral frame element made from aluminium or plastics material may be very light in weight, and depending on the length and design of the flexible frame element and the availability of access equipment, it may be preferred to install the flexible frame element in low arches or tunnels without using the novel installation tools. Alternatively, the element can be attached at one end and then engaged against the soffit by using just one tool at the other end.
Of course, if the framework is to be used without panels, or if (unusually) the arch is inherently dry, no shields are required.
The invention may be applied to low arches in which the soffit curves upwardly from the ground or from a short distance above the ground, as well as to round, egg-shaped or horseshoeshaped tunnels and the like in which the soffit and the sides of the structure form a continuous curve, the width of the floor being less than the width of the tunnel at its horizontal diameter. In such cases, the support elements (support means) may simply comprise steel plates bolted to the floor, or the two ends of a beam laid transversely across the floor, or alternatively brackets or the like attached above floor level to the inner surface or structural lining of the tunnel, so that the flexible element extends part way around the soffit from side to side of the tunnel or alternatively right around the curve of the tunnel to terminate at the floor at either end. The support elements may also comprise an integral part of a permanent tunnel lining, which may form a rack or the like for receiving the installation tool.
All of these support means may incorporate or accommodate a screwthread or other adjustment mechanism for forcing the ends of the frame element apart or together (depending on how far the frame element extends around the circumference of the tunnel) so as to induce a compressive hoop stress which urges it outwardly against the inner surface of the tunnel into its installed position. Two frame elements may also be coupled together end-to-end by an expander which induces hoop stress. Such arrangements may be suitable for use for example in installing a waterproof inner lining in underground railway tunnels and station platforms.
The novel framework may also be installed in inclined tunnels, such as escalator (moving staircase) tunnels in underground railway stations, in which case the stanchions and frame elements may be arranged, either vertically in stepped relation or inclined normally to the axis of the tunnel, and may be supported additionally against downward movement by attachment to the structural lining of the tunnel and/or by additional bracing struts. Frame elements may also include pivotal joints so that the frame element at one end of an arch can be skewed to follow the end of the soffit where an arch is angled with respect to the longitudinal axis of the viaduct.
Wherever means are disclosed herein for performing a function, that means may comprise any arrangement which is capable of performing that function in its essential aspects as defined by the claims, and is not limited to the specific means described.
The locking structure can comprise any suitable arrangement for locking adjacent rigid portions of the frame element in the selected angular position.
The support elements (support means) can be any arrangement which supports the ends of the frame element securely in the installed position.
In very simple installations, such as in low arches in which the floor comprises a soft ground surface, each of the support means may simply comprise a steel stake driven into the ground, or a hole in the ground into which the respective end of the flexible element is placed (supported in its installed position hard up against the soffit) before the hole is filled with concrete. If preferred, the flexible element may be attached at one or both ends to a bracket which is bolted or otherwise secured directly to the structural lining which forms the inner surface of a tunnel, or to the masonry of a pier or soffit, in which case the brackets may be left permanently in position when the lining and framework are removed for maintenance of the structure. A stanchion or rack may be secured adjacent one or both brackets to receive the installation tool during installation of the flexible element
The frame element attachment structure of the stanchion, and the cooperating mounting or attachment structure of the frame element, can be any suitable means, including holes, flanges, slots, lugs, portion of the stanchion or frame element or other feature whatsoever, whether limited to that function or providing that function in combination with another essential or inessential function, which facilitates the attachment of the frame element to the stanchion or other support means. Preferably, the attachment means should allow the frame element to be vertically adjusted relative to the stanchion or support means during installation and prior to attachment.
The panel attachment structure of the stanchion can be any suitable means for attaching the panels, and need not comprise cooperating holes for receiving screws or other fasteners. For example, each frame element could provide a channel into which the edges of the panels or corrugated lining sheets can be inserted; alternatively, the frame elements could be adapted to allow the panels to be hooked on without the use of fasteners.

Claims

A method of installing a lining within a pre-existing arched structure (1);
the structure having a floor (7) and a soffit (5),
the soffit having curvature whereby it curves upwardly and inwardly from opposite, first and second sides (4, 4') of the structure to a crown line (8);
including providing at least first and second, elongate frame elements (70, 110, 640, 850, 860, 910), each frame element having first and second end regions;
fixing the first frame element in an installed position adjacent the soffit,
and then fixing the second frame element independently of the first frame element in an installed position adjacent the soffit in spaced relation to the first frame element;
and then attaching a plurality of sheets or panels (200) to the frame elements in the installed position thereof so as to support the sheets or panels within the structure;
characterised in that each frame element is flexible,
and during installation each frame element is formed into an arched configuration,
and supported in the installed position in the arched configuration by support elements (40, 600, 1000') arranged respectively at its first and second end regions;
and the arched configuration is obtained by supporting the frame element at its first and second end regions,
applying a compressive hoop stress to the frame element,
engaging the frame element pressingly against the soffit,
and flexibly deforming the frame element by means of the hoop stress between its first and second end regions so that it conforms to the curvature of the soffit.
A method according to claim 1, characterised by providing a pair of installation tools (300), each tool including a movement mechanism (303) and a frame element attachment mechanism (302);
releasably mounting the tools respectively at the first and second sides of the structure;
releasably mounting a frame element at its first and second end regions on the respective frame element attachment mechanisms so that the frame element is supported between the tools;
operating the movement mechanisms of both of the tools to raise the frame element pressingly against the soffit until it conforms to the curvature thereof;
fixing the frame element at its first and second end regions in the installed position;
and releasing the frame element from the tools and dismounting the tools.
A method according to claim 2, characterised in that the support elements are stanchions (40, 600, 1000'), and the stanchions are fixed to the floor respectively at the first and second sides of the structure, and the tools are releasably mounted on the stanchions.
A method according to any of claims 1 - 3, characterised by fitting to each frame element a separate, elongate, flexible, waterproof shield (140, 149, 150);
and then fixing each frame element in the installed position so that a region of the shield is interposed between the frame element and the soffit;
and then attaching the said panels to the frame elements with the shields partially overlapping the panels, so that the panels and the shields together form a water shedding surface facing towards the soffit.
A lining installed within a pre-existing arched structure (1),
the structure having a floor (7) and a soffit (5),
the soffit having curvature whereby it curves upwardly and inwardly from opposite, first and second sides (4, 4') of the structure to a crown line (8);
the lining including at least first and second, elongate frame elements (70, 110, 640, 850, 860, 910),
the first and second frame elements being installable and removable, each independently of the other;
each frame element having first and second end regions,
the frame elements being fixed in spaced relation, each in an installed position in which it is supported at its first and second end regions by respective support elements (40, 600, 1000');
and a plurality of panels (200) or sheets supported by the frame elements,
the panels or sheets being attachable to and detachable from the frame elements in the installed position thereof;
characterised in that between its first and second end regions each frame element is not attached to the structure, but extends adjacent the soffit in an arched configuration which conforms to the curvature of the soffit;
and in that each frame element is adapted to deform flexibly and conformably to the curvature of the soffit in response to a compressive hoop stress applied during installation.
A lining according to claim 5, characterised in that each frame element has an elongate, flexible, waterproof shield (140, 149, 150);
and the shields partially overlap the said panels so that the panels and the shields together form a water shedding surface facing towards the soffit.
A lining according to claim 5 or claim 6, characterised in that the support elements are stanchions (40, 600, 1000') extending upwardly from the floor respectively at the first and second sides of the structure, and a plurality of beams (181) are supported between the stanchions, and a second floor (187) is supported on the beams.
A lining according to any of claims 5 - 7, characterised in that each frame element comprises a plurality of rigid portions (72, 112, 820, 861, 911) joined in series by hinge portions (73, 113, 821, 862, 912),
the rigid portions being pivotable about the hinge portions during installation through a limited range of movement so as to define an obtuse angle at each respective hinge portion, independently of the other hinge portions, on an inner side of the frame element which faces away from the soffit in the installed position;
and the range of movement at each hinge portion is constrained to substantially prevent the formation of a reflex angle between the respective adjacent rigid portions on the inner side of the frame element;
and each frame element is engaged pressingly against the soffit in the installed position;
and the hinge portions are not locked, the rigid portions remaining free to pivot about the respective adjacent hinge portions when the frame element is dismounted from the respective support elements.
A lining according to any of claims 5 - 7, characterised in that each frame element (850, 860, 910) comprises a plurality of rigid portions (820, 861, 911) joined in series by hinge portions (821, 862, 912),
the rigid portions being pivotable about the hinge portions during installation through a limited range of movement so as to define an obtuse angle at each respective hinge portion, independently of the other hinge portions, on an inner side of the frame element which faces away from the soffit in the installed position;
and each hinge portion is provided with a remotely lockable locking structure (830, 890, 920), each hinge portion being locked by the respective locking structure to prevent the respective adjacent rigid portions from pivoting about the hinge portion in the installed position.
A system for installing a lining within a pre-existing arched structure,
the structure having a floor and a soffit,
the soffit having curvature whereby it curves upwardly and inwardly from opposite, first and second sides of the structure to a crown line;
including at least two support elements (40, 600, 1000);
at least two elongate frame elements (70, 110, 640, 850, 860, 910),
the frame elements being installable and removable, each independently of the other;
each frame element having first and second end regions,
the frame elements being fixable at their first and second end regions on respective said support elements so as to support the frame elements adjacent the soffit in an installed position;
and a plurality of panels (200) or sheets,
the panels or sheets being attachable to the frame elements after installation of the frame elements in the installed position;
characterised in that at least one hoop stress generating mechanism (300) is provided,
the hoop stress generating mechanism being mechanically engaged or engageable with a respective frame element,
and operable to apply a compressive hoop stress to the respective frame element when the frame element is supported at its first and second end regions adjacent the soffit;
and each frame element is adapted to deform flexibly and conformably to the curvature of the soffit in response to the said compressive hoop stress.
A system according to claim 10, characterised in that the at least one hoop stress generating mechanism comprises at least one installation tool (300),
the tool including a movement mechanism (303),
a frame element attachment mechanism (302),
and a mounting mechanism (301) for releasably mounting the tool at a side of the structure;
each frame element being releasably mountable at one of its end regions on the frame element attachment mechanism;
the movement mechanism being operable to raise a frame element mounted on the frame element attachment mechanism pressingly against the soffit.
A system according to claim 11, characterised in that a pair of said installation tools are provided,
and the first and second end regions of each frame element are releasably mountable, each on the respective frame element attachment mechanism of a respective one of the tools;
and each tool includes a pivot mechanism (305), the pivot mechanisms of both tools being operable simultaneously to allow a frame element mounted between the tools to be raised from a rest position to an upright position.
A system according to claim 11 or claim 12, characterised in that the or each tool is releasably mountable on a respective one of the support elements, and the movement mechanism is operable to raise the tool up the support element on which the tool is mounted;
and the respective end region of the frame element, when mounted on the frame element attachment mechanism, is also attachable to the support element on which the respective tool is mounted.
A system according to any of claims 10 - 13, characterised in that each frame element (70, 640) comprises at least one unitary piece of material including a plurality of rigid portions (72) joined in series by hinge portions (73),
each hinge portion comprising a flexibly deformable region of the material;
the rigid portions being pivotable about the hinge portions during installation through a limited range of movement so as to define an obtuse angle at each respective hinge portion, independently of the other hinge portions, on an inner side of the frame element which faces away from the soffit in the installed position;
and the range of movement at each hinge portion is constrained to substantially prevent the formation of a reflex angle between the respective adjacent rigid portions on the inner side of the frame element.
A system according to any of claims 10 - 14, characterised in that each frame element is provided with an elongate, flexible, waterproof shield (140, 149, 150);
and the shields are arranged to partially overlap the said panels when the panels are attached to the frame elements, so that the panels and the shields together form a water shedding surface facing towards the soffit.