GB2409491A - Safety rails for trestle platform - Google Patents

Abstract

A safety arrangement for a platform comprising trestles 12 overlaid by decking boards 14 comprises uprights 32 each standing separately on the ground adjacent a supporting leg of a trestle, and having a lower portion connected to a trestle leg by spacers 36 and an upper portion extending above platform level and providing guard rail supports 44, this upper portion being cranked toward the platform whereby the centre of gravity is shifted so as to produce frictional locking of slidable collars 38 against the trestle legs. Supports 44 may be dimensioned to receive two thicknesses of board, and in other embodiments may lie above the platform (Figs 3, 4) and the uprights may be in the form of two interconnected columns (Fig 5): the supports may receive a toe board, a mid-rail and an upper guard rail

Description

240949 1

WORK PLATFORM STRUCTURE AND SAFETY ARRANGEMENT THEREFOR

This invention relates to work platform structures and in particular to safety arrangements therefor.

The invention is primarily, but not exclusively, concerned with low-level platform structures, often called bandstands or trestles, and improving user safety insofar as this may be achieved by providing one or more guard rails to prevent user and/or object from falling from the structure platform and improving the stability of the platform structure against toppling, particularly as a result of providing such guard rail or rails at a relatively high position.

Increasingly stringent legislation is being enacted in respect of the provision of suitable guard or safety rails for work platform structures used at the range of heights up to 2 metres hitherto satisfied by unguarded decking boards overlying trestles or like configuration Whereas there may be a number of design options available for trestle-based substitutes to include guard rail provisions in such work platform structures, this is of little comfort to individuals and organizations who have invested in having stocks of trestle based work platforms if such structures cannot be made to comply with the requirements of such legislation retrospectively.

Patent specification GB-A-2364733 sets out the nature of low level platform structure in the form of building trestles, that is, where discrete trestle units, each comprising leg units and horizontal cross beams, are spaced apart and joined by decking planks to define a platform at which a workman, such as a bricklayer, can work above ground level and receive materials temporarily stored on the platform as work progresses. It is usual, but by no means essential, for such work platforms to be adjustable in height, either to provide access to specific work or continued access as a piece of work, such as a wall, grows in height from the ground.

The aforementioned publication makes mention of the safety aspects of such platforms which, although not high above the ground in absolute terms, account for a disproportionate number of accidents and injuries. That publication is directed to a safety rail arrangement which is intended to impede the falling of users and/or materials from the edge of the platform and effectively interconnecting adjacent trestles in a rigid manner.

Several embodiments are described therein which in common have elongate upright members carried on, and/or securely fixed to, the supporting legs of the spaced apart trestles so as to provide mounting features above the level of the platform for horizontally interconnecting safety rails. The rails are mounted with respect to each upright member to prevent the uprights moving towards or away from each other and, by implication, movement of the otherwise independent trestles. .. .-

However, it is apparent that in some of the embodiments the sought after safety against falling from the platform given by the rails is compromised by shifting of the centre of gravity of the railed platform structure itself. In addition to any increased turning moment due simply to the additional weight carried at a distance from any foot, a user who hitherto would usually be reluctant to place himself or materials close to the edge of the platform, thereby tending to keep the centre of gravity of the platform well inboard of the feet, may choose to make use of the platform right up to the edge protected by the safety rails, and possibly contribute further to instability of the platform structure in respect of toppling about the trestle supporting feet as a fulcrum.

One embodiment described therein addresses the issue of stability by having safety rail- mounting uprights standing on the ground adjacent the trestle supporting legs and secured thereto by clamps, so as to provide with the horizontal safety rails enhanced rigidity of the overall structure, and providing the ground-supported uprights with braced feet extending away from the platform to displace a turning fulcrum further from the platform. However, some users within the industry feel concern regarding such extending feet as potential accident sources, as a near ground level hazard that may cause tripping or being vulnerable to impact by heavy machinery, putting platform users at renewed risk.

Nevertheless, in all of the embodiments described therein it is vital for the strength and stability of the structure that the safety rails interconnect and brace the spaced uprights of the modified platform structure.

There is also a further concern amongst those tasked with enforcement of site practices and legislation on the issue of safety that embodiments such as those described may permit users to circumvent safety features that they feel impede their work rate.

It may be felt by some users that the time required to properly assemble a modified platform arrangement in order to provide safety rails is not well spent, particularly if they have hitherto worked without them, and even if the structures are assembled properly and safely, there may be a temptation on the part of the users to interfere with, or remove, parts 0- of the additional structure to improve work rate, putting in danger themselves, and more particularly others who in ignorance trust the structure. . . . . Therefore, if there is the prospect of a safety arrangement not being securely fixed, or by being partially or fully removed during working, this is of concern to those charged with ensuring compliance and may form an obstacle to such arrangements being recommended or approved.

It appears that in the above mentioned publication, in each of the embodiments described that are based upon the use of a conventional, preexisting trestle, the additional safety arrangement may be partially or totally removed without interfering with the platform structure as provided by the trestles and decking.

A similar work platform structure defined by trestles with overlying boards and modified in respect of providing safety rails above the platform level is described in GB-A-2378978.

It will be appreciated that the trestle structure discussed in GB-A2364733 and GB-A- 2378978 is only one form of platform structure for which similar safety considerations apply. For example, a trestle configuration may exist in which the characteristic features of individual and essentially two dimensional trestles, supporting legs and cross beam, are formed in a three-dimensional structure equivalent to such trestles connected fixedly to each other below the platform level rather than as discrete items, and to this end it is considered appropriate to refer herein in a general sense to a work platform structure consisting of spaced apart trestle configurations, which configurations include inter alla, discrete trestles.

It is an object of the present invention to provide, for attachment to a work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, a safety arrangement of simple and economical construction which mitigates disadvantages and drawbacks of known arrangements, and permits continued use of such existing structures.

It is another object of the present invention to provide a method of improving the safety of such work platform structure.

It is furthermore an object of the present invention to provide a work platform structure including such a safety arrangement.

According to a first aspect of the present invention a safety arrangement for attachment to a work platform structure, consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, comprises at least one upright member associated individually with, and adapted to be attached to, an associated supporting leg, the or each upright member comprising a lower section, dimensioned to stand alongside a said supporting leg, and an upper section dimensioned to extend beyond the decking plane of the platform to at least a height required of a guard rail for the platform structure, said lower section having a foot operable to support the upright member on the ground surface adjacent the supporting leg and having spaced apart along its length at least two stand-off members each configured to effect coupling of the lower section to a said supporting leg, and the upper section S comprising at least one guard rail mounting feature, the lower section stand-off members each being arranged to maintain a substantially fixed distance between the lower section and supporting leg laterally and to permit some relative movement longitudinally, and at least upper section rail mounting feature being arranged to support in use a rail offset with respect to the lower section in the direction of the stand-off members the centre of gravity of the upright member, when supported upright by the foot, being displaced from the upright member lower portion and, when coupled to a said associated supporting leg, operable to bias the upright member to lean towards the trestle configuration and effect frictional interference locking in respect of relative movement between the upright member and the support leg of the trestle configuration.

According to a second aspect of the present invention a work platform structure platform - -- structure comprises a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, and a safety arrangement as defined in the preceding paragraph wherein associated with at least one trestle configuration there is a said upright member comprising a lower section standing alongside a said supporting leg, and an upper section extending beyond the decking plane of the platform to at least a height required of a guard rail for the platform structure, said lower section having a foot operable to support the upright member on the ground surface adjacent the supporting leg and having spaced apart along its length at least two stand-off members each configured to effect coupling of the lower section to a said supporting leg and the upper section comprising at least one rail mounting feature, the lower section stand- off members each being arranged to maintain a substantially fixed distance between the lower section and supporting leg laterally and to permit some relative movement longitudinally, and at least one upper section guard rail mounting feature supporting a guard rail offset with respect to the lower section in the direction of the stand- off members such that the centre of gravity of the upright member is displaced from the upright member lower portion and operable to bias the upright member to lean towards the trestle configuration and effect frictional interference locking in respect of relative movement between the upright member and the support leg of the trestle configuration.

According to a third aspect of the present invention a method of improving the safety of a work platform structure, consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, comprises coupling to at least one spaced apart pair of trestle configuration supporting legs a corresponding pair of upright members each having a lower portion supported on the ground laterally spaced from its associated supporting leg and an upper portion extending above the platform, and joining the upper portions by way of one or more guard rails, the method further comprising coupling each of the lower portions to its associated and spaced supporting leg to permit substantially only longitudinal movement between them, disposing offsetting the centre of gravity of the upright members offset towards the platform and causing frictional locking between the upright members, and supporting legs.

Embodiments of the invention will now be described by way of example with reference to .2.

the accompanying drawings, in which: Figure 1 is a perspective view of a first embodiment of a work platform structure..

comprising traditional trestles and interconnecting decking boards incorporating a safety .

arrangement in accordance with the present invention, comprising singular upright members and guard rail mounting features accessible from outboard of the platform, and an optional ladder support, Figure 2 is an end view of the work platform structure of Figure 1 showing the disposition of the guard rail mounting features in relation to the platform, Figure 3 is an end view of a second embodiment of work platform structure in accordance with the invention in which one or more of the guard rail mounting features are disposed overlying the platform, Figure 4 is a perspective view of a third embodiment of a work platform structure in accordance with the present invention employing upright members generally similar to Figure I but being of two-part, telescopically extensible form.

Figure 5 is a perspective view of a fourth embodiment of work platform structure in accordance with he present invention, showing a multiple dimension, ladder-like upright member and guard rail mounting features accessible from inboard of the platform, and optional horizontal bracing means between upright members, and Figure 6 shows a variant construction of guard rail mounting feature.

Referring to Figures I and 2, a work platform structure 10 confirms a plurality of trestles 121, 122, 123 124 spaced spread apart in a linear array and overlying them and interconnecting them plurality of decking boards 14, 142. The decking boards are here shown as elongate planks whose lengths greatly exceed their widths W. but they may instead comprise a single board having the width of the platform.

The decking boards are located in a platform plane, indicated at 15, raised from the ground by the trestles to a height H pre-determined for the work required.

The trestles 121, 122, are substantially identical and only trestle 121 will be described in detail. The trestle 121 comprises a pair of supporting legs 2OIA and 2OIB' spaced apart by bracing bars 221 and upstanding with respect to feet 24IA and 24IB respectively.

Each of the supporting legs is fixed at its upper end to a cross beam 261 which at its ends overhangs, slightly outboard of the legs, upstanding lugs 28A and 28B between which to receive and retain the decking boards 14' etc. The trestle 121, is essentially a two-dimensional structure, apart from the feet 24IA and 241B which are braced to permit the trestle to stand upright and, in an array of similarly disposed trestles, give longitudinal stability to the platform as a whole. Sideways stability is provided by virtue of the small overhang whereby the centre of gravity of the platform itself acts between the leg pair of the (and each) trestle.

The supporting legs 2OIA and 2OIR may be of fixed length, to provide a platform of fixed height, or more usually, and as shown here, may be extendable. Each supporting leg, such as leg 2OIA comprises two components 2OIAL and 2OIA[J. The component 2OIAL comprises a tube fixed to, and extending from the foot 24IA and the component 2OIAU comprises a tube, or bar, fixed to and extending from the cross beam 261 and into the end of the tubular component 2OIAL. The supporting leg 2O1B is likewise formed of two components 2OIBL and 201 BU.

15:.'.

The telescopic arrangement of supporting legs permits the cross beam 261 to be raised and, , lowered with respect to the feet and retained at a predetermined height by means of cross drillings in the leg components and retaining pins 29IA and 29IB which may be .

conveniently mounted on a horizontal bracing bar for sliding transversely to the supporting a....

legs. It will be appreciated that by removal of the retaining pins the leg components may.... .

be separated and the beam removed for storage or replaced by one having longer leg .

components.

Such trestles and a work platform structure assembled therefrom are known and to the

extent described above constitute prior art.

In accordance with the invention there is provided a safety arrangement indicated generally at 30. The safety arrangement is separate from, and designed to be used with, the above described work platform structure 10.

The safety arrangement 30 comprises one or more upright members, 32,. In this particular embodiment, there are a plurality of upright members, two of which are shown at 321, and 322, and each is associated individually with a respective trestle of the array; the upright member 321 is associated with trestle 121, the upright member 322 is associated with trestle 122 and so on.

Each upright member, such as 321 associated with trestle 121, is formed from singular bar or tube of steel and comprises a lower section 32L dimensional to stand alongside the trestle supporting leg 2OIA and an upper section 321U dimensional to extend beyond the decking plank 15 of the platform to at least a height required of a guard rail for the platform structure.

The lower section 3211, has a foot part 341, operable to support the member upright on the ground surface near the supporting leg 2OIA, spaced therefrom by virtue of two (or optionally more) stand-offmembers 36IL and 36IU Each of the stand off members 36[L and 36IU is fixed rigidly, for example by welding, to the lower portion 32L and extends laterally thereof in a direction that is, when the upright member is alongside the trestle, towards the supporting leg 2OIA and to which it is coupled by a collar-like coupling piece 38IL and 38IU respectively. Each coupling piece collar surrounds the leg so as to be a sliding fit, that is, arranged to maintain a substantially fixed distance between the lower section 32'L of the upright member and the supporting leg laterally of the leg but to permit some relative movement longitudinally of the leg.

Because of the trestle structure, including bracing bars, feet and separable leg components, the lower coupling piece, 3811,, takes the form of a split collar that is formed from separable parts assembled around the leg and held together by screw 391 or the like. Although the upper coupling piece 38L may be of similar construction, preferably it comprises, as shown, a circumferentially complete collar that is fixed to the end of the stand off member and dimension to slide over the end of a component of the supporting leg 2OIA of the trestle disassembled state before the leg components are assembled telescopically and the cross- beam configured.

As discussed above, the leg 2OIA comprises telescopically mounted components (2OIAL] and 2OIAL) one of which has a smaller cross section than the other to slide therein. In this respect the upper stand off member 36IU is mounted at such a height as to be aligned with one supporting leg component or the other and coupling piece collar 38IU is dimensioned accordingly.

Thus, having regard to the positioning of the upright member 321 alongside the associated trestle 12, the upright member is disposed standing off from the trestle by a substantially fixed distance but each of them find their own level by virtue of their independent feet and the longitudinally (vertically) sliding ability of the coupling pieces 38IL and 38IU and supporting leg 2OIA.

15:. .

The particular benefit obtained by having at least one coupling piece formed as a. . circumferentially complete collar is that, notwithstanding the requirement to assemble the trestle cross beam after the associated upright member is coupled, when the work platform..

structure is fully assembled and ready for use, or in use, it is not thereafter possible to a....

simply remove the upright member and compromise the safety of the arrangement without....

firstly dismantling the platform decking and trestle or trestles.

The upper section of the upright member is arranged to provide mounting features for one or more guard rails running along the platform in the direction of the trestle array, that is orthogonally to the longitudinal, upright direction of the members and in practice running between and supported by a pair of adjacent upright members 321 and 322 etc. Although the form, number and positions (heights) of such guard rails may vary, in keeping with published safety standards, this embodiment has guard rails at three heights which in relation to the work platform (plane) one a toe rail or toe board disposed at the level of the platform to prevent materials or tools lying on the platform from being pushed over the edge, a mid-level rail and a high-level rail each spaced from the platform (plane) to prevent users or any large items from falling from the platform.

It will be appreciated that insofar as the platform may be configured to assume different working heights, the relationship between the mid-level and high-level rails may be chosen to ensure that the position of each is disposed to perform a guarding function over a range of heights. Although there is a considerable degree of latitude in respect of placing of the mid-level and high-level rails, this is less true for the toe rail which should not be raised clear of the platform surface when the platform is at its lowest or extend insufficiently above the level of the platform when it is at its highest.

The upper section 32U of the upright member 32 includes a crank 42 which offsets it, with respect to most of the lower section, in the direction of the stand off members 36U and OWL, that is in the direction towards the associated trestle. e

Three, guard rail mounting features 44, 442, and 443 are formed by the offset, cranked region of the upper section. Each mounting feature comprises a channel, such as 462 open towards the top of the upright member between side walls 472A and 472B and, one of which,2.

(472B) comprises the upper section 32'U and the other of which is separated therefrom by a. . bight region. Said other side wall 472B comprises a stub upright 492 of fixed or adjustable length and the bight region comprises a transversely extending branch 492 of the upright .

member which displaces the stub upright, and thus forms the guard rail mounting channel disposed at the side of the upper section in the direction opposite to the stand-off members, that is facing away from the platform in use.

Figure 1 shows in position only an upper guard rail 50 and Figure 2 shows only a lower or toe guard rail 52. Each guard rail, per se is elongate in the direction of the platform (trestle configuration array) and arranged to be mounted by disposing it in corresponding mounting feature channels of a pair of spaced apart upright members, such that it is supported by each. In this embodiment, but not essentially, each guard rail is provided by a plank having standardised dimensions and as used for the decking boards 14 etc of the platform.

Typical dimensions are a length of 300 cm, width of 200 cm and thickness of between 32 and 38 cm between opposite faces. Each guard rail mounting channel is arranged to receive such a guard rail plank mounted on its edge and, insofar as each upright member may be shared between two adjacent pairs of upright members, the channel is of such width as to hold at least two overlapping rail planks face to face. Because of the nature of each guard rail plank and orientation within the channel, the guard rails are adequately retained by their weight, but if desired, a manually adjustable clamp 54 may be provided to effectively vary the width of the channel to grip and locate firmly any number of planks within the channel in a vice-like manner. It will be appreciated that other mechanisms may be provided for effectively varying channel width, such as varying the length of the transverse bight region or position of the stub upright along it.

As indicated above, the guard raid mounting features, and in use the guard rails themselves are offset with respect to the lower section of the upright member in a direction towards the platform of the structure. :...

As indicated above, the disposition of the guard rail mounting features, and in use, the guard rails, offset with respect to lower section of the (and each) upright member displaces A, the centre of gravity of the each upright member 32 etc inboard, towards the associated. . trestle configuration such that when the upright member is coupled to the supporting leg of the trestle configuration, the off-balance weight of the upright member (and guard rails) biases the upright member to lean towards the trestle configuration and effect frictional .

interference locking between the erstwhile longitudinally slideable coupling pieces and the supporting leg.

Thus, each upright member, having assumed an independently supported position on the ground adjacent the platform structure, in use is braced by the structure against significant displacement and each upright member effectively forms a buttress against displacement or toppling of the platform structure.

It will be appreciated that whereas it is preferred as a safety feature to have both guard rail mounting features and the guard rails supported thereby both offset with respect to the lower section of the upright member and contributing towards it leaning towards the platform structure, it is not necessary to have both the mounting features and the rails so disposed provided that the overall effect of mounting features and guard rails does so.

Whether or not it is undesirable for the mid-level and high-level guard rails to overlie the platform is a matter of choice, insofar as such overlying may inhibit maximum use of the platform, the position of a low level toe board or rail is important when the platform may be varied in height. Thus, at least the lowest of the mounting features 44 is disposed with respect to the upright member lower section, the stand off members and the platform overhang of the associated trestle configuration, such that the lower guard rail 52 being a decking plank of significant width, is disposed at a height above the lowest intended working height of the platform. To accommodate changes in platform height this lowest mounting feature channel may be made particularly deep or adjustable in depth by virtue of the stub upright as shown ghosted at 48, so as to hold at least two rails stacked on top of ' ' each other in an upward direction if there is any requirement to raise the effective level of the toe guard rail. . :. - "

As indicated above (in respect of Figure 1), offsetting the guard rail mounting feature channels with respect to the lower section towards the platform effectively offsets the centre of gravity of the upright member, both with and without the guard rails present. By having the upper section cranked and offset, this gives access to the channel for receiving the elongate rails from outboard of the platform. Thus, for ease of working and improved safety, the guard rails can be installed and removed from one or more ladders placed against the edge of the platform rather than firstly being loaded onto the platform.

However, when it comes to users climbing up to or down from the platform, whether to transfer themselves or materials, such ladder placement against the edge of the platform is preferably avoided. To this end, as shown in Figure 1, the safety arrangement 30 optionally comprises at an upper section of at least an upright member 322 a ladder rest bar 60 extending laterally from the member in a direction substantially opposite to the direction of the stand off members, that is away from the platform, and including restraining means indicated generally at 62, to secure the ladder with respect of the bar. An upwardly extending projection 64 is operable to inhibit a ladder (shown ghosted at 66), resting on the bar, from sliding to the end of the bar and a manually operable tie means, such as a latch, an overlying clamp or loopable rope or chain 66 may beprovided for preventing inadvertent lifting of the ladder from the rest bar.

Another option that arises from the use of guard rail mounting channels is the possibility of, with a lower channel at the same height as the platform decking, mounting a board or plank on the bight region as a floor thereto, thus providing a step for transfer to the platform or effectively a small increase in platform width, within the constraint that such floor, being offset with respect to the lower section in a direction inboard towards the platform, contributes to leaning of the upright member and stability of the platform structure. . : ...

The above described embodiments address potentially conflicting requirements of a platform adjustable in height and an upright member of fixed length. .. a Other configurations are possible that achieve the same operating principle. For example, for use with a work platform structure of fixed height, as shown at 10' in the end view of '; Figure 3, the trestle configurations such as 12' do not have extensible supporting legs, a ^ second embodiment of safety arrangement 30' has the coupled upright member or members 32' etc may stand off such that the mounting features 44' etc overlie, or hold the guard rails overlying, the platform. Alternatively, even if the lowest level mounting feature requires to be displaced, and support a toe board not overlying the platform, the mid-level and high level guard rail mounting features may dispose the respective guard rails overlying the platform.

An alternative approach, not dependent upon platform height, is shown in Figure 4 in a third embodiment of work platform structure and safety arrangement also according to the present invention. The platform structure 10 corresponds to that described above. The safety arrangement 130 comprises at least one upright member 1321. The upright member differs from the upright member 321 described above in that the lower section 1321 comprises two telescopically adjustable parts 1321[A and 132ILB retainable with respect to each other by a locking pin or through bolt arrangement 133] such that the upper section 1 32U of the upright member can be disposed at an optimum height next to a work platform defined in height by the telescopically adjustable supporting legs of the associated trestle configuration. In the embodiment, the lower stand-off member 1361L is fixed to the lower part of the lower section and coupled to the lower part of the supporting leg. The upper stand-off member 136 is fixed to the upper part of the lower section and coupled to the upper part of the supporting leg, so that the trestle configuration cross beam, and thus the height of the upper section of the upright member can be varied in height together.

In general it does not matter which part of the supporting leg the circumferentially complete coupling piece encircles, providing it permits a degree of longitudinal (upright) movement during set-up of the safety arrangement. :e

In all of the above described embodiments it will be appreciated that subject of the need to At..

provide a low-level guard rail or toe board and the need to avoid fouling between the. . . platform and any guard rail mounting feature, the disposition and heights of the mounting features may be varied. .' :': It will be appreciated that the stability that comes from having separately standing supporting legs and upright members and the frictional locking of the displaceable coupling pieces may be achieved other than by having the coupling pieces fixed with respect to the stand off members and the stand off members fixed with respect to the lower section of the upright member. For instance, (not shown) one or each of the stand-off members may be fixed with respect to the associated supporting leg of the trestle configuration and the coupling piece formed as a collar slidable longitudinally with respect to the lower section of the upright member. Alternatively, one or each stand-off member may be made longitudinally slideable with respect to both the lower section of the upright member and the supporting leg and respond to the leaning tendency of the upright member to effect the above described frictional locking with both.

The upright member, shown in Figure 1 as a singular bar or tube, may comprise a number of such bars or tube interconnected in a two or threedimensional lattice for even greater rigidity.

Referring now to Figure 5, this shows a fourth embodiment of work platform structure 210 in which an array of trestle configurations 121 etc. and decking boards 141 etc. is substantially as shown at 10 in Figure 1 and numbered accordingly.

Safety arrangement 230 therefor comprises one or more upright members 2321 etc each associated with a trestle configuration, coupled to a supporting leg thereof.

The upright member 232' likewise comprises a lower section 232IL terminating in a foot 234' and, as an upward continuation, an upper section 232tJ. The upright member, for both of its sections is formed as a two-dimensional lattice or ladder-section, comprising a pair of parallel bars or tubes interconnected by cross pieces 2331 The lower section has affixed thereto two spaced apart stand-off members 2361! and 236IU coupled to the associated upstanding supporting leg 2OIA for longitudinal (vertical) motion as described above. The upper section 232IU has guard rail mounting features 2441, 2442 and 2443 in the form of channels, 2461, 2462 and 2463, each formed by a transverse bight region and . stub upright but displaced from the upper section in the same direction as the stand off .:.

members, towards inboard of the platform.

The guard rail mounting channels are arranged to receive longitudinally overlapping guard rails formed by decking planks disposed on their side edges, but in this configuration placed into, or removed from, the channels from the platform.

The two-dimensional structure of the upright member 2321 gives more rigidity and less inclination to bend then a single rod or tube but otherwise behaves similarly insofar as it is arranged for the centre of gravity to be offset from acting centrally through it foot and encouraging frictional locking between the coupling pieces of the stand- off members and the associated trestle configuration supporting legs.

A further feature, shown in respect of the upright member 232 of this embodiment, but applicable also to the upright members 32 and 322 of Figure 1, is a supplementary brace 270 used to extend between receptors 272 of a pair of spaced upright members when only two or a relatively small number of upright members are in use. One or more braces may be employed between any pair of upright members and each brace may be adjustable in length if required.

In all of the above described embodiments, the guard rail mounting features have been described as channels defined by extensions and protrusions to an upright member formed of one or more bars or rods, such channels being of a similar bar-like or skeletal nature in order to accommodate guard rails that are substantial decking planks and longitudinally overlapping. It will be appreciated that such mounting channels may be defined by having laterally extensive walls, such as illustrated at 344 in Figure 6, such a channel being able to offer greater support to less robust guard rails and/or permit adjoining rails to be accommodated in end-to-end relationship rather than overlapping. Alternatively, such a channel arrangement may permit a safety arrangement to be more easily formed with only a single upright member, where a guard rail, extending longitudinally of the platform structure and transversely of the upright member may be essentially centred and balanced into longitudinal disposition in a single mounting channel with or without the assistance of a lateral vice-like clamp 354.

The guard rails may take any suitable form other than the above described planks, and/or be made of other materials. The guard rail mounting features may take other forms, such as receptacles to receive projections from guard rails or projections to receive apertures in guard rails, and extending in any orientation to receive a complementary rail mounted from any direction.

It is common to all of the above described embodiments that the safety arrangement may be assembled with respect to a platform structure without the use of tools, although this may be varied in respect of a particular guard rail and mounting feature combination, or if a special tool is deliberately employed to deter attempts to dismantle by unauthorised persons. . . . -en.. .. . ë A.. ë .

Claims (32)

1. A safety arrangement for attachment to a work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, the safety arrangement comprising at least one upright member associated individually with, and adapted to be attached to, an associated supporting leg, the or each upright member comprising a lower section, dimensioned to stand alongside a said supporting leg, and an upper section dimensioned to extend beyond the decking plane of the platform to at least a height required of a guard rail for the platform structure, said lower section having a foot operable to support the upright member on the ground surface adjacent the supporting leg and having spaced apart along its length at least two stand-off members each configured to effect coupling of the lower section to a said supporting leg and the upper section comprising at least one rail mounting feature, the lower section stand-off members each being arranged to maintain a substantially fixed distance between the lower section and supporting leg laterally and to permit some relative movement longitudinally, and at least one upper section guard rail mounting feature being arranged to support in use a guard rail offset with respect to the lower section in the direction of the stand-off members the centre of gravity of the upright member, when supported upright by the foot, being displaced from the upright member lower portion and, when coupled to a said associated supporting leg, operable to bias the upright member to lean towards the trestle configuration and effect frictional interference locking in respect of relative movement between the upright member and the support leg of the trestle configuration.

2. A safety arrangement as claimed in claim 1 in which each stand off member is arranged to be rigidly fixed with respect to one of the upright member lower section and the associated supporting leg.

3. A safety arrangement as claimed in claim 2 in which each stand-off member is fixed with respect to the lower section of the upright member.

4. A safety arrangement as claimed in any one of claims 1 to 3 in which the stand off members each comprise at least one coupling piece configured to substantially surround a said associated supporting leg.

5. A safety arrangement as claimed in claim 4 in which at least one coupling piece comprises a circumferentially complete collar arranged to be coupled to a said supporting leg by passage of an end of said leg through the collar.

6. A safety arrangement as claimed in any one of the preceding claims in which at least one guard rail mounting feature is disposed to effect disposition of a guard rail mounted thereat at a height from the ground in excess of the maximum height of the platform of an associated structure, and overlying the platform.

7. A safety arrangement as claimed in any one on claims 1 to 5 in which the respective lengths of the stand off members and disposition of at least lowest guard rail mounting feature with respect to the lower section of the upright member are arranged to dispose in use, said lowest guard rail alongside, but not overlying the platform. ë -

8. A safety arrangement as claimed in any one of the preceding claims in which each guard rail mounting feature is disposed at a side of the upper section in the direction opposite to the stand off members, and in use adjacent a platform structure facing away from the platform, whereby each guard rail is mountable and Remountable from outboard of the upright member.

9. A safety arrangement as claimed in any one of the preceding claims in which the upper section of the upright member is cranked to offset the or each guard rail mounting feature defined thereby with respect to the lower section in the direction of the stand off members.

10. A safety arrangement as claimed in any one of the preceding claims in which each guard rail mounting feature is arranged to support at least one guard rail extending laterally of the upright member at an adjacent upright member.

11. A safety arrangement as claimed in any one of the preceding claims in which at least the lowest guard rail mounting feature is arranged to support a plurality of guard rail members stacked edge to edge to accommodate variations in associated platform height.

12. A safety arrangement as claimed in claim 11 in which the upper section at least one guard rail mounting feature comprising a channel (or alternative mechanism - see faxed sketch) open towards the top of the upright member between the upright member and between side walls one of which comprises, or is supported by, the upper section of the upright member and the other of which is separated therefrom. .

by a bight region. ...

13. A safety arrangement as claimed in claim 11 or claim 12 in which the mounting.

feature channel comprises the upper section of the upright member, the bight region a transversely extending branch of the upright member and a stub upright. . I::-.

14. A safety arrangement as claimed in any one of claims 11 to 13 in which the mounting feature channel is of such width as to hold at least two guard rails overlapping face-to-face.

15. A safety arrangement as claimed in any one of claims 11 to 14 in which each said guard rail mounting channel is arranged to receive as a guard rail at least one decking plank of standard width and/or thickness.

16. A safety arrangement as claimed in any one of the preceding claims in which the lower section of the upright member is adjustable in length.

17. A safety arrangement as claimed in 16 in which the lower section of the upright member comprises two telescopically adjustable parts at least one of the stand off members being associated with one part and at least one other stand off member being associated with the other part.

18. A safety arrangement as claimed in any one of the preceding claims in which the upper section of the upright member includes a ladder rest bar extending laterally thereof in a direction substantially opposite to the direction of the stand off members and including restraining means to secure the ladder with respect to the bar.

19. A safety arrangement as claimed in claim 18 in which the restraining means comprises an upwardly extending projection operable to inhibit sliding of a ladder resting on the rest bar from sliding to the end thereof. ..

20. A safety arrangement as claimed in claim 18 or claim 19 in which the restraining means comprises tie means operable to prevent lifting of the ladder from the rest. , he.:

21. A safety arrangement as claimed in any one of the preceding claims including at .

least one upright member and at least one laterally extending guard rail mounted. ..

thereon.

22. A safety arrangement as claimed in claim 21 comprising a plurality of said upright members each arranged to be coupled to a respectively associated supporting leg spaced apart from an adjacent upright member and associated with each pair of adjacent upright members at least one guard rail arranged to extend between them and be supported by each.

23. A safety arrangement as claimed in claim 21 or claim 22 in which each guard rail comprises a decking plank of standard width and/or thickness.

24. A work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, and a safety arrangement as claimed in any one of claims I to 23 wherein associated with at least one trestle configuration there is a said upright member comprising a lower section standing alongside a said supporting leg, and an upper section extending beyond the decking plane of the platform to at least a height required of a guard rail for the platform structure, said lower section having a foot operable to support the upright member on the ground surface adjacent the supporting leg and having spaced apart along its length at least two stand-off members each configured to effect coupling of the lower section to a said supporting leg and the upper section comprising at least one guard rail mounting feature, the lower section stand-off members each being arranged to maintain a substantially fixed distance between the lower section and supporting leg laterally and to permit some relative movement longitudinally, and at least one upper section guard rail mounting feature supporting a guard rail offset with respect to the lower section in the direction of the stand-off members such that .e the centre of gravity of the upright member is displaced from the upright member lower portion and operable to bias the upright member to lean towards the trestle configuration and effect frictional interference locking in respect of relative movement between the upright member and the support leg of the trestle configuration.

25. A work platform structure as claimed in claim 24 wherein the supporting legs of the trestle configuration are variable in length to vary the height of the platform plane and wherein the or each upright member of the safety arrangement has its lower portion variable in length to permit the or each guard rail to be disposed in a substantially fixed relationship with the platform plane.

26. A work platform structure as claimed in claim 25 wherein the trestle configuration supporting legs each comprise two components one component extending from an enlarged foot unit and the other component extending from a cross beam, said components being telescopically mounted with respect to each other and separable to dismantle the trestle configuration, and wherein the safety arrangement comprises, for each upright member, at least one stand-off member having a circumferentially complete coupling piece mounted on one of the telescopically assembled supporting legs irremovable other than by separation of the leg components.

27. A work platform structure as claimed in any one of claims 24 to 26 wherein the upper section of each upright member has at least the lowest guard rail mounting feature disposed to support a said rail adjacent the edge of, but not overlying the platform.

28. A work platform structure as claimed in any one of claims 24 to 27 in which the lowest guard rail mounting feature is arranged to provide a toe rail at the level of the platform and said lowest guard rail feature is arranged to mount one or more guard rails to provide a toe rail above the platform level irrespective of variation in height of the platform.

29. A method of improving the safety of a work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, comprising coupling to at least one spaced apart pair of trestle configuration supporting legs a corresponding pair of upright members, each having a lower portion supported on the ground laterally spaced from its associated supporting leg and an upper portion extending above the platform, and joining the upper portions by way of one or more guard rails, the method further comprising coupling each of the lower portions to its associated and spaced supporting leg to permit substantially only longitudinal movement between them, disposing offsetting the centre of gravity of the upright members offset towards the platform and causing frictional locking between the upright members and supporting legs.

30. A method of improving the safety of a work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, the method being substantially as herein described with reference to the accompanying drawings.

31. A safety arrangement for attachment to a work platform structure consisting of a plurality of spaced apart trestle configurations and overlying interconnecting decking boards defining a platform plane raised from the ground by supporting legs, the safety arrangement being substantially is herein described with reference to and as shown in any one of Figures 1 to 5 of the accompanying drawings.

32. A work platform structure substantially as herein described with reference to, and as shown in Figures 1 and 2 or any one of Figures 3 to 6 of the accompanying drawings. A. ë.. .e ë