GB2285472A - Cantilevered scaffolds - Google Patents

Abstract

A scaffold for launching from the inside of a building through a window aperture to provide external access to transversely adjacent walls and windows, includes a torque box 1 securable at one end to the inside of the building by a cross beam (3) (Fig. 1, not shown) so as to protrude through the aperture at the other end. When positioned, the outer end of the torque box 1 is transversely fitted with a cantilevered sequence of a walkway connector 30 and walkway modules 50, 60 and 70. <IMAGE>

Description

A Cantilevered Scaffold This invention relates to a cantilevered scaffold capable cf being launched through a single window aperture of a building and extended laterally so as to provido external access to the adjacent walls and windows of the building.

Various scaffolding platforms are knows for use in exterior maintenance of buildings, most of which need to be either erected from ground level or suspended from roof level. These can be fairly cumbersome and obstructive devices, often causing disruption over a far greater region of the building than is necessary for the projected task, and requiring time consuming construction procedures. Scaffolding platforms are also knoam which are supported upon clamps attached to the cills of two or more adjacent windows.

The present invention seeks to provide a scaffold which can be quickly assembled and launched from a single window aperture of a building at any chosen level so as to extend transversely in t'ne particular region of interest, with minimal disturbance to other regions and windows of the building.

In accordance with the present invention a cantilevered scaffold for launching over the cill of an aperture in a wall of a building so as to be extendable transversely therefrom includes: a torque member having a longitudinal axis disposed in use substantially perpendicular to the will and protrusive across the cill; a cross-beam transversely engageable with the torque member inwardly of the cill 7ld securable to the building; and 3 ctilhrar walkway having one end engageable with the torque member outwardly of the cill so as to extend radially outwards from the longitudinal is.

For ease of transportation and assembly the cantilever walkway preferably comprises a wal''ay rnr.ctor attachable to the torque member and a plurality of walkway modules co-engage able in end to end configuration, each being individually attachable in seTuenoe otitwardly from the walkway connector The modules may alternatively be telescopic or hinged so as to fold together.

Conveniently the cross-beam is secured to the building during construction and use of the scaffold by horizontal attachment between a pair of adjustable length props vertically disposed in thrust between a local floor and ceiling of the building.

In a preferred arrangement, the scaffold further includes a cill clamp attachable to the torque member intermediate the cross-beam and the walkway so as to engage the cill.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings of which Figures 1 and 2 are interior and exterior views respectively of a window aperture fitted with an assembled torque member and cross-beam, Figure 3 is a view of a walkway connector for attachment to the torque member of Figure 2.

Figure 4 depicts the walkway collector of Figure 3 attached to the torque member of Figure 2, and Figures 5 to 7 sequentially depict attachment of walkway modules to the assembly of Figure 4.

The part-assembled scaffold illustrated in Figure 1 comprises a rectangular torque box 1 fabricated from a high strength weldable aluminium alloy, supported across a cill 2 by means of a cross-beam 3, an inner clamping bracket 4 and an outer clamping bracket 5.

The cross-beam 3 to which the clscsp 4'is centrally attached, is horizontally clamped by means of hinged end pieces 6 and locks 7, between two adjustable-length props 8, each having a tilt foot 9 at each end respectively braced against a floor 10 and a ceiling 11. Load spreading plates (not shown) may be inserted between the feet 9 and the floor 10 of the ceiling 11 if necessary. The props 8 are further braced apart by one or more horizontal spacer bars 12.

The torque box 1 is attached to the inner clamping bracket 4 by means of bolts 13 and 14. The bracket 4 also carries two adjustable clamping pads (not visible) which are braced against the inside of the cill 2 by screws 15 in opposition to the outer clamping bracket 5 which has been attached to the torque box 1 at an appropriate position beyond the cill by means of bolts 16.

The outer end of the torque box 1, which can be more clearly seen in Figure 2, is provided on each side with a pair of bearing jaws 20 and associated locating guides 21, to which jaws a walkway connector 30 (see Figure 3) can be attached at either side of the box 1.

The walkway connector 30 is arranged to be attached below the level of the torque box 1 to ensure that the final scaffold will arrive at a convenient access level below adjacent windows on the same floor of the building. This disposition is achieved by providing the connector 30 with a leverage portion 31 which reacts against the underside of the box 1 when the connector 30 is pivotally suspended from one pair of the bearing jaws 20 by means of journals 32. In order to assist entry of the journals 32 into the jaws 20, the leverage portion 31 is provided with two side members 33 which can be slidably engaged with the locating guides 21 when the connector 30 is being lowered for attachment (with portion 31 downwards) from the top of the box 1.Once engaged, the connector 30 is allowed to pivot round until the leverage portion 31 engages with the underside of the box 1, the counterbalancing weight of the connector 30 being so distributed as to ensure that this position is maintained.

The connector 30, which then projects laterally from the box 1 (see Figure 4), is also provided with a step 34, a pair of walkway bearing jaws 35 at the top outer edge and a pair of walkway pinning lugs 36 at the bottom outer edge, to which jaws and lugs a walkway module 50, now to be described with reference to Figure 5, can be attached.

The walkway module 50 comprises two parallel lightweight frameworks 51 of high flexural strength fabricated from a resin bonded carbon fibre material and inter-connected by cross members 52, to which cross members are secured a deck 53 fabricated from a nonslip aluminium honeycomb material. A near end 54 of the frameworks 51 is provided with a pair of journals 55 and a pair of lugs 56 respectively co-operative with the bearing jaws 35 and the lugs 36 of the connector 30. The far end 57 of the frameworks is provided with a pair of bearing jaws 35 and a pair of pinning lugs 36 identical with those of the connector 30. Bobbins 58 are appropriately located in the frameworks 51 so as to provide fixing points to which the jaws and lugs can be bolted.

In assembly, the module 50 is attached to the connector 30 by resting the journals 55 in the jaws 35 (Figure 5) and is then lowered to the horizontal position by means of ropes 59 attached adjacent the far end 57.

The walkway can be further extended to required length by adding two further modules 60 and 70 in a similar manner, as illustrated in Figures 6 to 8.

The cantilever action of the walkway holds the modules 50, 60 and 70 in co-engaged position without need to conjoin the bottom chords of the walkway modules by pinning the co-operating lower edge lugs 36 ald 56. However, if the wallzlay is used as a bridge, ie the far end is to be supported on a balcony or ledge for example, these lugs must be pinned.

Some deflection of the cantilevered walkway inevitably occurs due to rotation of the torque box and to elastic deflection of the materials used. The maximum deflection of the embodiment described when built to an overall walkway length of 5m with modules of 0.3m thickness, is 0.ism. With these dimensions the embodiment can be launched through a minimum window aperture of 0.9m x 0.5m, the walkway being arranged to run clear of the wall by about 0.3m in order to clear down-pipes, buttresses etc.

All the components of this embodiment are man-portable, the heaviest being the torque box which weighs about 27kg, and the lightest being the walkway modules each weighing about 12kg. Once the components have been collected together at a launch site the scaffold can be fully launched within 5 minutes.

The steps of the assembly and launch procedure are as follows: a. Erect the props 8 and the spacer bar 12.

b. Fit the inner clamping bracket 4 to the cross-beam 3.

c. Offer up and attach the cross-beam 3 to the props 8.

d. Attach the outer clamping bracket 5 to the torque box 1.

e. Offer up the torque box 1 and hook the outer clamping bracket 5 over the cill 2 f. Attach the torque box 1 to the inner clamping bracket 4.

g. Tighten all connections.

h. Fit the walkway connector 30 to the torque box 1 i. Fit the first walkway module 50 to the connector 30.

j. Fit the second walkway module 60 to the first walkway module 50 k. Fit the third walkway module 70 to the second walkway module 60.

Randrails (not shown) may be fitted to the walkway modules if required.

It will be apparent that scaffolds in accordance with the present invention need not necessarily be deployed with the walkway horizontal but may be arranged so as to have a walkway inclined at any angle in the plane parallel with the wall so as to provide access to particular features of interest at other levels.

In such arrangements the bottom chord of the walkway must be pinned and the deck 53 may be omitted to permit the cross members 52 to be used as ladder rungs.

Claims (6)

Claims

1. A cantilevered scaffold for launching over the ciii of an aperture in a wall of a building so as to be extendable transversely therefrom including: a torque member having a longitudinal axis disposed in use substantially perpendicular to the wall and protrusive across the cill; a crossbeam transversely engageable with the torque member inwardly of the cill and securable to the building; and a cantilever walkway having one end engageable with the torque member outwardly of the cill so as to extend radially outwards from the longitudinal axis.

2. A scaffold as claimed in Claim 1 wherein the cantilever walkway comprises a walkway connector attachable to the torque member and a plurality of walkway modules co-engageable in end to end configuration, each being individually attachable in sequence outwardly from the walkway connector.

3. A scaffold as claimed in Claim 2 wherein the torque member is laterally provided with at least one pair of mutually aligned bearing jaws substantially axially parallel with the said longitudinal axis, and the walkway connector includes a step portion and a conjoined leverage portion mutually having a pair of journals pivotally engageable with the bearing jaws and relatively having a weight distribution respective to the journals selected to ensure that, when the journals are located in use in the bearing jaws, the leverage portion will be levered upwardly against the underside of the torque member by the deadweight of the step portion.

4. A scaffold as claimed in Claim 3 wherein the step portion has an end face remote from the leverage portion and disposed to locate in tt substantially vertical plane in use, parallel with the said longitudinal axis, which end face is provided at its upper and lower edges respectively with a pair of walkway bearing jaws and a pair of wal.r.- way pinning lugs each substantially axially parallel with the longi- tudinal axis, and each walkway module is provided at one end with a simIlar set of walkway bearing jaws and walkway pinning lugs and at the other end with a set of journals and pinking lugs co-operative therewith.

5. A scaffold as claimed in any one of the preceding claims further including a cill clamp attachable to the torque member intermediate the cross beam and the walkway so as to engage the cill.

6. A cantilevered scaffold substantially as herein before described with reference to the accompanying drawings.