GB2457644A - Trestle platform - Google Patents

Abstract

A trestle comprises a working platform and a safety guard located above the working platform. The safety guard does not require additional ground contacting supports beyond those used to support the trestle platform. The trestle may comprise two sets of supports positioned at opposite sides of the trestle from each other. The supports may be connected by cross members. The supports may comprise lower and upper frames which releasably engage one another to allow vertical adjustment of the trestle. The lower frame may comprise first and second supports which engage first and second legs of the upper frame. On leg of the upper frame may be longer than the other and may have means for attachment of the safety guard. The upper frame may also comprise a gate holder for receiving a gate so that the gate can pivot within the holder. A gate received in the holder may be secured in or biased towards a closed position. The longer leg of the upper frame may also comprise a holder for receiving a support for a ladder.

Description

* 2457644 Trestles The present invention relates to trestles, as well as to components thereof, and to kits for use in constructing trestles.

Trestles are well known in the construction, repair and renovation industries. They are used by a wide range of craftsmen, including builders, plasterers, brick layers, painters, electricians, etc. They can be used indoors or outdoors and are usually constructed on site from a kit.

A trestle comprises a generally horizontal working platform mounted upon a plurality of supports. Access to the working platform is normally provided via a ladder or a ramp.

Alternatively, if the trestle is low enough, then a worker may simply step on or off the platform, although this is less preferred and can be contrary to official "Working at height regulations" (sometimes abbreviated to WAFIR).

The trestle platform is generally formed from a number of standard scaffolding boards that are laid fiat adjacent to one another and are supported by a frame. Most commonly the platform comprises four scaffolding boards but any appropriate number can be used, commensurate with the width of the trestle.

Stops (sometimes referred to as "upstands") are usually provided on the trestle frame to prevent the scaffolding boards falling off the sides of the trestle.

The frame may also include one or more bridging units that span adjacent supports. These can provide additional rigidity if the distance between adjacent supports is large. They bridging units can also be useful in regions where scaffolding boards meet end-to-end, because they allow scaffolding boards to remain flat and thereby reduce the risk of tripping that might otherwise result from sagging or raised ends. S 2

Trestles have been widely used for many years. They provide a convenient means of allowing workers to work over large areas at height without the need to constantly climb up and down ladders and to move ladders along as work progresses.

They are generally used at lower heights than scaffolding platforms and thus they avoid the need for extensive scaffolding, as well as the time and skilled labour needed to erect this.

Typical working heights for platforms of trestles are below 2 metres.

For example, two standard working heights are at about I and about 1.5 metres. Adjustable trestles are known that allow a platform to be located at both of these working heights.

Whilst standard trestles are convenient to use and erect, they can provide significant safety hazards. Indeed many accidents have occurred due to workers or materials accidentally falling from trestles.

Even if trestles are used at low heights, injuries can still be severe or even fatal. The very fact that trestles are generally used at low heights compared to scaffolding can lead to complacency and can increase the risk of injury.

There are therefore significant health and safety considerations when using trestles. In addition to health and safety concerns there is also the problem that expensive tools or materials may become damaged if dropped from a trestle.

There is therefore a major need to reduce the risk of people, tools or materials accidentally falling from trestles. In particular, there is a major need to increase safety for workers on trestles as well as for passers by or for other workers on site.

It is now well known in the art to provide trestles with safety guards (known in the art as "handrails"). These are positioned adjacent a trestle platform and extend above the height of the platform. These are very useful in providing physical barriers to prevent or reduce the risk of accidents due to people or materials falling from the trestle platform.

Indeed trestle safety guards are now required by the working at height regulations of many countries, including the U.K. The nature of a safety guard that is used with a trestle can vary and many designs are known. Typically a relatively solid lower plate is provided that is adjacent to the platfonn and prevents debris passing through it. A mesh may be provided at a higher level. The mesh has the advantage of reducing weight and allowing good visibility, whilst still preventing large pieces of material from falling through it. (Various mesh sizes can be used, as desired, depending upon the materials being used.) A rail is commonly provided at the top of the safety guard and can be conveniently gripped by a worker, allowing the worker to steady himself when required. This can be useful for example if the worker stumbles or becomes unbalanced (e.g. due to a gust of wind or simply due to tiredness). The rail may be part of a frame around the safety guard that provides rigidity.

Known safety guards for trestles are generally provided in kits that are designed to provide "add on" safety features for standard trestles.

Thus, with most known systems, a standard trestle is first constructed and then a safety guard and associated supporting members are attached to the standard trestle.

One such system is sold by Cheshire Building Developments Ltd of Bollington, Cheshire, in England, under the trade mark of Staybills TM The Staybills system comprises a series of additional ground contacting supports (beyond those used for the trestle platform itself) to which safety guards are mounted.

The additional supports are clamped to existing supports that run along one side of the standard trestle and are said to reduce the risk of overturning.

Thus there are three series of supports in total: 1) trestle platform supports running along one side of the standard trestle 2) trestle platform supports running along the opposite side of the standard trestle * . . 3) supports for the handrail (to prevent overturning due to the increased weight at one side of the trestle).

Another "add on" system that utilises additional supports is obtainable from Generation of Oldbury, The West Midlands, in England. l'his is known as the Generation trestle handrail system. This comprises four components that are required to be attached to an existing trestle system.

One of these components is a safety guard that is attached via a horizontal mounting to a cross member of an existing trestle. The safety guard then overhangs the legs of the trestle.

This shifts the centre of gravity of the construction and additional ground contacting supports are therefore provided to stabilise the construction. These are attached to the existing legs of the trestle.

However the additional supports can themselves provide safety hazards because they jut out from the trestle and can increase the risk of tripping.

Another system is known as the SmartGuard system and is provided by Beaver of Basildon, Essex, in England.

This is similar to the Generation system described above in that a safety guard is again mounted to cross members and significantly overhangs the legs of a trestle, thereby requiring additional stabilising supports. These supports are described in an advertising brochure for the SmartGuard system as extending the base dimension of the trestle by more than 50%.

This arrangement can therefore again pose a tripping hazard. It can also make the trestle unsuitable for use in confined environments, given the increase of over 50% in width.

A still further system is described in GB 2404945. Here a device with a horizontal sheath is fitted onto a cross member. The device has an aperture through which an end stop of the trestle protrudes so that the sheath can be held in position. A clip is also provided for fitting * S 5 over the end stop of an adjoining trestle and said to improve stability. The device comprises a sleeve for'receiving an upright that is used to support a trestle handrail. Thus additional uprights are required beyond the legs of the standard trestle. This system therefore suffers from many of the disadvantages of the other systems discussed above.

Furthermore, if the clip described in GB 2404945 is used as suggested to connect the trestle to an adjacent trestle (in order to improve stability) this greatly complicates construction and use because two trestles must be erected side by side.

Indeed if a device as described in GB 2404945 is mounted on both sides of an existing trestle cross member and the two devices are connected to a further trestle at either side by the clip then it is necessary to erect three trestles.

It will be appreciated from the foregoing description that all of the existing systems described above focus upon attaching a safety guard to the side of a standard trestle and require additional stabilisation.

The present invention goes in a radically different direction from such systems.

According to the present invention there is provided a trestle comprising a working platform and a safety guard located above the working platform; wherein the safety guard does not require additional ground contacting supports beyond those that are used to support the trestle platform.

The trestle requires only a single set of supporting uprights at one side of the trestle and a single set of supporting upriglits at the opposite side of the trestle.

Preferably the supports at opposing sides of the trestle are interconnected via one or more cross members.

In a desired embodiment the supports for the trestle comprise lower and upper frames that releasably engage one another. Thus the supports are formed from interconnecting frames. * 6

Engagement of the upper and lower frames may be by mating male and female members, although there are many other possibilities. (These possibilities include simply clamping, screwing or bolting components together, etc., and all of these are within the scope of the present invention).

The lower frame may comprise hollow uprights that are shaped to receive legs of the upper frame or the legs of the upper frame may be hollow and may be shaped to receive uprights of the lower frame. Alternatively, but less preferably, the lower frame may comprise one hollow upright that is shaped to receive a leg of the upper frame and one upright that is shaped to be received by a hollow leg of the upper frame.

Releasable securing means may be provided for securing the lower and upper frames to one another in a predetermined position. For example pins, clips, or releasable locks may be used.

The releasable securing means preferably passes through appropriately positioned apertures in the upper and lower frame so as to secure the frames in a fixed position relative to one another. When it is desired to release the securing means this can easily be achieved by sliding it out of the apertures. This may be done, for example, when dismantling the trestle.

Preferably this is done only once the platform of scaffolding boards has been first removed from the trestle.

The upper and lower frames co-operate and this ensures that legs used to support safety guards are positioned directly above supports of the trestle platform.

Turning now to the construction of the lower frame, as indicated above this preferably comprises two interconnected upright supports. Connection will generally be by at least one cross member.

The cross member is preferably substantially perpendicular to the upright supports so that it is substantially horizontal when the lower frame is on level ground. It may be welded to the uprights. (Alternatively casting or moulding may be used to form the desired shape.) * . .. 7 Preferably the lower frame comprises a plurality of cross members for increased strength and rigidity. For example two cross members may be provided.

Desirably each upright support of the lower frame has an aperture drilled at a predetermined height.

A plurality of apertures may even be provided at different predetermined heights to allow increased flexibility in positioning the trestle platform at various heights.

As indicated earlier, first and second upright supports of the lower frame are positioned for engagement with the first and second legs of the upper frame. These supports can therefore be at a different position from the supports of a standard trestle, taking into account the function of the upper frame not only in supporting a trestle platform but also in supporting a safety guard adjacent to the platform. (The lower frame engages with the upper frame and will therefore be shaped accordingly.) Turning now to the construction of the upper frame, this preferably also comprises a cross-member. This interconnects the first and second legs and this may again be done welding, casting or moulding, etc. The first and second legs are shaped for engagement with the first and second supports of the lower frame.

At least one of the legs of the upper member is preferably provided with means for releasably attaching a safety guard thereto. (If desired, such attachment means can be provided on both legs, although this is not essential and is not necessarily preferred, as discussed later.) The releasable attachment means may for example comprise a plurality of hooks that can engage the mesh of a safety guard.

As an alternative to providing hooks on the leg it is possible to provide them on the safety guard and to provide the leg with means for engaging the hook (e.g. with hoops or eyes). * 8

Indeed the exact nature of the releasable attachment means is not limiting, provided that it performs its function. Thus a wide range of possibilities exist (including catches, straps, ties, bolts and sockets, etc). All are within the scope of the present invention, provided that the safety guard can be appropriately positioned and subsequently removed when it is desired to dismantle the trestle.

The attachment means may be provided at different positions on the leg. For example, two sets of hooks may be provided with one set being located on the leg at right angles to the other set. This provides a convenient way of attaching safety guards at corner regions.

The leg that comprises the releasable attachment means is preferably located directly above the support of the lower frame that receives the lower part of the leg. Thus a straight upright is formed from two mating parts.

This contrasts with many prior art devices where the support for the safety guard is located to one side of a leg that is used to support the platform. The present invention therefore provides an elegant way of avoiding the need for additional stabilisation at ground level by changing the design of the trestle itself to take into account the positioning of the safety gate (rather than simply providing "add on" components to a standard trestle).

The leg that supports the safety guard is preferably longer than the other leg of the upper frame (although this is not essential and the legs may be of equal length if this is desired.) For example it may be at least 25%, at least 50% or at least 100% longer than the other leg.

Thus one leg of the upper support is preferably substantially longer than the other leg.

This is because the other leg is not necessarily required to be attached to a safety guard.

(The trestle may for example be positioned against the wall of a building or other construct to allow rendering, painting etc. and the provision of long legs or of a safety guard at this side could impede access.) * 9 Indeed the second leg may be arranged so that it does not extend above the level of the cross member of the upper frame. This cross member is used to support the working platform of the trestle. The fact that the second leg does not extend above the level of the cross member can therefore be useful in allowing additional width for the platform or for other components (e.g. a kick board).

The cross member can also be provided with a stop that prevents scaffolding boards falling off the side of the trestle.

In a preferred embodiment the stop is in the form of a receiving member shaped to receive a gate and allow the gate to pivot therein. Thus it can have the dual purpose of serving both as a stop and as a mounting for a gate.

It may be generally cylindrical in shape. It is preferably located at one end of the cross member (For example it may be attached to the cross-member by welding or it may be an integral part of a unitary upper frame that is formed by casting or moulding.) The gate receiving member may be lubricated (e.g. with grease or oil) for smooth operation.

It may be coated with a low friction material.

The provision of a gate receiving member on a trestle support is advantageous in allowing a gate to be positioned at a variety of alternative locations along the trestle. This provides great flexibility in use and can further contribute to increased safety.

This contrasts with most prior art systems where such flexibility is not provided and where it may be necessary for an operator to detach a panel to allow access to the trestle platform at a desired location and then to reattach it at a later stage.

Such prior art systems carry a risk that the operator will fall when removing or subsequently reattaching a panel. There is also a risk in that the panel will fall and become damaged / cause injury. Even if this does not occur there is still the inconvenience of safely storing a detached panel until it is ready to be reattached. * 10

These difficulties are avoided by the preferred embodiment of the present invention in which a gate holder and gate are used.

The gate can be of any desired construction as long as it fits into the gate holder to allow pivoting and can be safely opened and closed.

Preferably a means for securing the gate in a closed position is provided. This can be a bolt latch, catch etc. Desirably however the gate is provided with a fitting that is positioned so that it can be releasably engaged with the top of a leg that is used to connect safety guard.

The fitting (e.g. a sleeve, bracket, loop, chain, or hook) may for example be arranged to be placed over the top of the leg that is attached to the safety guard. Thus when the fitting is located over the top of the leg it keeps the gate in a closed position. The gate can then be easily opened by lifting it slightly so that the top of the leg is no longer engaged and the gate is free to pivot.

Turning now to access to the trestle platform, this will usually be provided by means of a ladder.

It is well known in the art to provide a trestle with a support, against which a ladder can be positioned to facilitate access to the trestle platform. The ladder support is generally removable and can be attached to a fitting provided on the trestle.

In the case of the present invention it is preferred that one or more of the legs that are used to support the safety barrier are also provided with a fitting (e.g. a bracket) for receiving a support for the ladder.

If desired, all of the legs that are used to support the safety barrier may comprise such a fitting. This allows great flexibility in positioning the ladder. Indeed several ladders may be used at different positions.

* . . . 11 It will be appreciated from the foregoing description that a completed trestle of the present invention may comprises several components that are assembled together on site. (Less preferably the trestle may first be constructed elsewhere and transported to the site.) The components of a trestle of the present invention may be provided individually or may be provided in kit form.

Thus the present invention includes not only a completed trestle, but also components thereof, whether provided individually or provided together with other components as a kit.

The following components are included within the scope of the present invention: a) a lower frame as described above b) an upper frame as described above c) a gate as described above.

A construct comprising the upper and lower frames when joined together is also within the scope of the present invention. This may be preassembled to save time later on.

(Less preferably, a unitary construct of a single frame may be provided so that separate upper and lower frames are not required to be attached to one another. However this alternative provides a fixed height for the trestle platform and does not therefore have the advantage of upper and lower frames that can be connected to allow a trestle platfonn t be positioned at two or more different heights.) A preferred kit of the present invention includes a plurality of upper frames and a plurality of lower frames as aforesaid.

Desirably the kit includes a plurality of releasable securing means for the upper and lower frames, although these may be provided separately if desired. * 12

The kit may further comprise one or more safety guards that can be attached to the upper frames. If desired safety guards that are longer than nonnal can be provided to reduce the number of components needed for a given length of trestle.

In addition to the components described above a plurality of boards for forming the platform of the trestle may be included in the kit. Alternatively these may be omitted, because they are commonly available and may significantly increase the weight and/or size of the kit.

The kit may optionally include other components various other components as is well known to those skilled in the art of providing builder's trestles.

For example one or more of the following components may be provided: I) a ladder for providing access to the trestle platform 2) a support for the ladder 3) one or more bridging units for providing additional rigidity between supports 4) a toe board (sometimes known as a kickboard) for indicating the edge of a platform The kit may include instructions for assembling the components together to provide a trestle of the present invention.

The kit may be pre-packed. It may be provided in a suitable container (e.g. a crate).

Thus a large variety of kits are within the scope of the present invention.

The kits can be used to produce trestles of a wide variety of shapes and sizes.

For the avoidance of doubt it should be noted that the term "trestle is used herein in a broad sense.

Thus it includes not only trestles that have a working platform, but also trestles that have a platform used to temporarily store materials. * 13

Such trestles for receiving working materials are sometimes known in the trade as "loading bays". They allow materials (e.g. bricks, render, paint, etc) to be loaded thereon and to be easily accessed from an adjacent trestle with a working platform, without the need for such materials to be stored on the working platform.

This is important because the working platform should be kept as clear of materials as possible in order to minimise the risk of tripping, overloading etc. A "loading" trestle will generally be at substantially at the same height as a "working" trestle. (The loading trestle can be constructed using the same components as the working trestle. Thus it may comprise upper frames, lower frames and boards as aforesaid. It may also comprise one or more gates.) It allows materials to be easily accessed by workers without the need to have to repeatedly climb up and down ladders.

If desired, the loading trestle may be clamped or otherwise attached to the working trestle, but this is not essential, given that the present invention allows very stable trestles to be constructed. Indeed it can be advantageous not to join the loading and working trestles together. This simplifies construction. It can also increase safety because if the loading trestle is accidentally overloaded or is damaged this will not necessarily affect the working trestle.

It will be appreciated by those skilled in the art that trestles of the present invention represent a significant breakthrough in design. They can be used for any purpose where a stable platform is required and are not limited to use in the construction field or related

fields.

Having described the invention in general terms, it will now be described by way of example, without limitation thereof.

Reference is made here to the accompanying illustrative drawings; wherein: Figures 1 shows a trestle of the present invention. S 14

Figure 2 is a partial view of the trestle shown in Figure 1 taken from one end and showing a gate of the trestle in an open position.

Figure 3 shows the same trestle as shown n Figure 1, but with a loading bay positioned adjacent to the trestle to allow easy access to materials.

Figure 4 shows a lower frame that is used in the construction of a trestle as shown in Figures 1 to3.

Figure 5 shows an upper frame that is shaped so that fits into the lower frame shown in Figure 4 Figure 6 shows the upper frame shown in Figure 5 when it is fitted into the lower frame shown in Figure 4, with a cross member of the upper frame abutting an upper cross member of the lower frame.

Figure 7 shows the upper frame shown in Figure 5 when fitted into the lower frame shown in Figure 4 at a position that is higher than the position shown in Figure 6. Here the upper and lower frames are releasably secured to one another by two clips that pass through apertures provided in the frames.

Referring firstly to Figure 1, a completed trestle of the present invention is shown adjacent to a wall. It can be used by workers wishing to treat the wall (e.g. to re-point it or paint it).

The trestle comprises a level working platform comprising scaffolding boards that are supported by a plurality of supports. The supports are connected to safety guards positioned above the platform (known in the trade as "handrails").

In the embodiment shown in Figure 1 each safety guard comprises a lower plate, a mesh extending above the plate and an upper rail that can be easily gripped. However many variations in design of the safety guard are possible and all can be used in the present invention.

* . .. 15 The safety guard performs a number of fimctions. Most importantly, it can prevent a worker on the platform accidentally falling off the platform, or at least significantly reduce the risk thereof. It can also stop materials falling off the platform and possibly injuring passers by.

The safety guards shown in Figure 1 are releasably attached to uprights by a series of hooks.

The uprights that support the safety guards extend downwards to ground contacting members. These are located at one side of the trestle (the nearside shown in figure 1) and are also connected to a series of ground contacting members at the other side via cross members. No further ground contacting members are required.

Importantly, no additional stabilisers are required for the safety guards. The footprint of the trestle can therefore be veiy compact and the risk of tripping due to extensively protruding supports at the side of the trestle is avoided.

The trestle is shown with a ladder resting against a ladder support. The ladder support simply slots into a receiving bracket provided on an upright of the trestle. Each of the uprights that supports the safety guards has such a bracket. This enables the ladder to be positioned at a wide variety of locations so as to allow easy access to the working platform via a gate that can be positioned adjacent to the ladder Additional gates can also be provided. For example, a gate is provided at the right hand end of the trestle shown in Figure 1.

The gate is shown in Figure 2 in an open position. It is supported by a housing that is part of an upper frame used to support the trestle (as described later with respect to Figure 5), The gate has a cap that can be fitted over an upright of the trestle to hold the gate in a closed position. The gate can however be easily opened simply by lifting it slightly and pivoting it.

The gate provides convenient access to the platform without the need to remove a safety panel. * 16

Turning now to Figure 3, a loading bay is shown that has been constructed adjacent to the trestle shown in Figure 1. The loading bay allows materials to be positioned so that they are easily accessible to workers on the working platform of the trestle.

A safety guard is shown removed from the loading bay so that materials can be easily loaded onto the platform of the loading bay. The safety guard has been removed to allow materials to be loaded onto the platform (not shown), but it can be easily replaced once materials have been loaded onto the platform by using hooks provided on the uprights.

A safety guard from the working platform has also been removed so that there is a clear path from the working platform to the loading bay to allow workers to collect materials without having to climb up and down ladders. This is particularly important if material (e.g. render) must be used quickly. It is also generally useful in contributing to increased efficiency.

The trestle comprising the loading bay does not need to be connected to the trestle comprising the working platform because both are stable enough to be self supporting.

There may therefore be a small gap between the two platforms. In practice, this is not normally a major problem. However, if desired, the gap may be bridged.

In a preferred embodiment a platform bridging device is provided that comprises an elongate member shaped to cover at least part of the gap (or to fit into the gap) and a plurality of cross members that rest on the platforms at the sides of the elongate member.

Most preferably two cross members are provided and are spaced apart along the elongate member, with each cross member having one arm that rests on the working platform and one arm that rests on the loading bay platform.

Desirably the platform bridging device is fairly flat and relatively thin so that it does not pose a significant trip hazard when in use.

The platform bridging device may be arranged for fixed attachment to the platforms. For example it may be provided with appropriately positioned holes or screws. However this is * 17 not normally necessary because the design of the platform bridging device allows it to rest in place without falling through the gap between the two platfonns.

The platform bridging device can of course be used for any desired purpose where bridging between two surfaces is required. Thus it is not limited to being used to bridge a loading bay and a working trestle but can for example be used to bridge two working trestles or two loading trestles.

The platform bridging device is advantageous over simply using scaffolding boards to bridge the gap, because it is more stable and also provides a lower risk of tripping. Desirably it is formed a rigid material (e.g. steel). Several such devices may be used together to bridge a long gap, with the devices being laid end to end.

Turning now to Figures 4 and 5, these show upper and lower frames respectively.

In use these would be connected together to provide a support for a trestle platform.

As shown in Figure 4, the lower frame comprises two upright tubes that are connected to one another via two horizontal cross members. An aperture is drilled in each of the upright tubes at the same height. This is for receiving a retaining clip, as described later. The tubes have square inner and outer cross sections, but this is not essential. Indeed the tubes can have any desired cross sections, provided that the upper and lower frames can be joined together.

The lower frame is self-supporting and includes a triangular base portion to help distribute load. The frame is symmetrical about a central vertical axis between the two upright hollow tubes. Thus each of the tubes is of the same height.

Turning now to the upper frame shown in Figure 5, unlike the lower frame this is not symmetrical. It has an unusual shape that is very different from anything known in the art.

It has two legs that fit into the hollow tubes shown in Figure 4. However the right hand leg shown in Figure is much longer than the left hand leg (over twice as long). This is because it comprises hooks for attaching a safety guard thereto. It has two sets of such hooks. One set projects to the left hand side of the figure. The other set projects out of the paper. The two S. 18 sets of hooks are at the same height, but are perpendicular to one another. This allows safety guards to be mounted at corner regions.

The upper frame shown in Figure 5 comprises a single cross member (although additional cross members can be provided in some embodiments if desired). This cross member carries an open cylindrical housing that is in a vertical position when in use and is shaped for receiving a gate. (See Figure 2, where a gate with a pivot housed within the cylindrical component is shown in an open position.) It is important to note that because each of the upper frames carries a housing that can be used for a gate, a gate can be positioned at a wide variety of possible locations, making the trestle extremely flexible in use.

The gate housing also functions as a useful stop. It prevents scaffolding boards falling off the side of the trestle where the gate housing is located, because the top of the housing is above the level of the scaffolding boards when they are laid down on top of the cross member of the upper frame.

Figure 6 shows the upper frame when placed into the lower frame and lowered until the cross member of the upper frame abuts the upper cross member of the lower frame. In this position scaffolding boards located on the cross member of the upper frame of a series of such supports would be about 1 metre high.

Figure 7 shows the upper frame when placed into the lower frame and releasably secured in place by clips that pass through apertures in the upper and lower frames. (Thus is at a higher level than if the upper frame were simply lowered into the lower frame until the cross members of the frames abut one another as shown in Figure 6.) In this position scaffolding boards located on the cross member of the upper frame of a series of such supports would be about 1.5 metres high.

The upper and lower frames therefore conveniently allow trestle platforms to be mounted at two different predetermined levels. Of course a series of spaced apertures could be provided * 19 in the upper and lower frames at different levels to allow even greater flexibility. This is also within the scope of the present invention. (Of course, as an alternative to using clips and apertures, any other releasable securing means could be used.) When constructing a trestle as shown in Figure 1, a plurality of supports comprising upper and lower frames would be constructed and spaced apart in a manner to allow scaffolding boards to be placed thereon. Bridging units can be used if the span between adjacent supports is large to provide additional support as is well known in the art. Safety guards can be easily attached via the hooks provided on the upper frames. As discussed earlier, one or more gates or ladders can also be provided to allow easy access to the scaffolding. A loading bay area can also be provided, as described earlier in connection with Figure 3.

The construction of the trestles is very simple and can be achieved in a few minutes even by unskilled workers. This is an important advantage because building trestles are often hired out in kit form and it is important that they can be easily assembled on site by people who are not necessarily familiar with them.

The trestles meet current UK working at height regulations and are of very compact and elegant design. This significantly reduces cost in manufacture, as well as the labour costs of assembling and dis-assembling trestles on site.

Furthermore, because additional stabilisers are not required, the risk of tripping over stabilisers is avoided and the trestle can also be used in confined areas where such stabilises would otherwise interfere with the use of the trestle.

Claims (29)

1. Claims 1. A trestle comprising a working platform and a safety guard located above the working platform; wherein the safety guard does not require additional ground contacting supports beyond those that are used to support the trestle platform.
2. 2. A trestle according to claim 1; wherein the supports comprise a single set of supporting uprights at one side of the trestle and a single set of supporting uprights at the opposite side of the trestle.
3. 3. A trestle according to claim 2; wherein the supports at one side of the trestle are connected to supports at the opposite side of the trestle via one or more cross members.
4. 4. A trestle according to any preceding claim; wherein the supports comprise lower and upper frames that releasably engage one another.
5. 5. A trestle according to claim 4; wherein the lower and upper frames are connected via mating male and female members.
6. 6. A trestle according claim 4 or 5 comprising releasable securing means for securing the lower and upper frames to one another in at least one predetermined position so that the trestle platform can be positioned at least one predetermined height above ground level.
7. 7. A trestle according to claim 6; wherein the releasable securing means comprises a member that fits into an aperture extending through the lower and upper frames when they are at said predetermined position.
8. 8. A trestle according to any of claims 4 to 7; wherein the lower frame comprises a first ground-contacting support at one side of the trestle, a second ground contacting support at the other side of the trestle, and at least one cross-member that interconnects said supports; the first and second supports being shaped for engagement with the first and second legs of the upper frame.
9. 9. A trestle according to claimS, wherein said lower frame comprises two cross members that interconnect the first and second supports.
10. A trestle according to any of claims 4 to 9; wherein the upper frame comprises first and second legs and at least one cross-member that interconnects said legs; the first and second legs being shaped for engagement with the first and second supports of the lower frame.
11. 11. A trestle according to claim 10; wherein said first leg is longer than said second leg and comprises means for attaching a safety guard thereto.
12. 12. A trestle according to claim 10 or claim 11; wherein said upper frame further comprises a gate holder for releasably receiving a gate in a manner so that the gate can pivot within the gate holder.
13. 13. A trestle according to claim 12; wherein said gate holder is connected to a cross member of the upper frame.
14. 14. A trestle according to claim 12 or 13 further comprising a gate located in said gate holder.
15. 15. A trestle according to claim 14; wherein the gate comprises means for securing it in a closed position and/or wherein the gate is biased towards a closed position.
16. 16. A trestle according to any preceding claim; wherein the first leg of the upper member further comprises a holder for receiving a support for a ladder.
17. 17. An upper frame that is suitable for use in a trestle according to any of claims 4 to 16.
18. 18. A lower frame that is suitable for use in a trestle according to any of claims 4 to 16.
19. 19. A gate that is suitable for use in a trestle according to any of claims 12 to 15.
20. 20. A bridging device for use in bridging two adjacent trestle platforms, said device comprising an elongate member and two cross members that are spaced apart along the arm and are shaped to contact each of the platforms
21. 21. An assembly comprising an upper frame according to claim 17 when engaged with a lower frame according to claim 18.
22. 22. A kit comprising a plurality of upper frames according to claim 17 and a plurality of lower frames according to claim 18.
23. 23. A kit according to claim 22, further comprising a plurality of releasable securing means for releasably securing the first frames to the second frames at a predetermined position
24. 24. A kit according to claim 22 or claim 23, further comprising at least one gate according to claim 19.
25. 25. A kit according to any of claims 22 to 24, further comprising one or more safety guards for attachment to the upper frames.
26. 26. A kit according to any of claims 22 to 25, further comprising a plurality of boards for forming the trestle platform.
27. 27. A kit according to any of claims 22to26, further comprising at least one bridging device according to claim 20.
28. 28. A method comprising using a kit according to any of claims 22 to 27 in the construction of a trestle according to any of claims 1 to 16.
29. 29. The invention as substantially hereinbefore described, with reference to the accompanying drawings.