GB2225227A - Work platform and connector therefor - Google Patents

Abstract

A connector (2) for use in constructing a work platform has guide channels (6) for legs joined by a cross member (4) which bears a deck (28) and by a second cross member (8) below. A platform is assembled from two such connectors, a deck (28) and four legs (34). Restraining means (18) extend (30) at least partially over the deck (28) and hold it onto each connector (2) allowing the entire platform to be picked up as one piece. The legs (34) are held by clamps (10) which press them into the guide channels. Teeth (9, 11) on the clamps and in the channels engage the legs. A step 36 may be fitted around a leg 34 and is adjustable along the leg by tilting the tread plate 38 upwardly against the bias of a tongue 52 thereby disengaging teeth 49, 50 from the leg 34, so that the step can be slid up or down the leg 34. When the step is released the tongue 52 will bias the teeth 49, 50 into contact with the leg 34. <IMAGE>

Description

PLATFORM This invention relates to an adjustable working platform which can be used to enable access to heights somewhat greater than can be reached by a person standing at ground level.

Portable platforms which provide a raised horizontal working surface supported by legs are known but in general do not enable adjustment of the height and are unsteady if placed on an uneven surface.

Builders' scaffolding can be set up on uneven ground and can provide a horizontal deck at almost any desired height. However, such scaffolding is slow to erect and adjustment of the height is only accomplished by partial dismantling.

The present invention seeks to enable the convenient provision of a platform which can be adjusted to various heights, at least in preferred forms can be adjusted to rest stable on uneven ground, and can be a portable unit.

Broadly, a first aspect of the present invention provides a connector for use in constructing a work platform, which connector comprises a bearer for a deck, a pair of guides to receive respective legs slidable in the guides, the connector having releasable restraining means to secure a leg releasably to each guide and to secure a deck to the bearer.

In order to construct a platform a pair of connectors of the invention are used. A horizontal deck is secured to the bearers of the two connectors so as to extend between and join the connectors. A leg is secured to each guide of each connector thus giving a four legged structure with a deck joined to the legs by means of the connectors.

According to one particularly preferred feature of the invention, the restraining means for the deck are shaped to extend at least partially over the deck thereby to hold the deck onto the bearer suitable restraining means are clamp means which are so shaped and can be tightened to press the deck onto the bearer.

For each connector it is strongly preferred that the bearer extends between and is rigid with the two guides.

Desirably at least one cross member in addition to the bearer extends between the guides and is rigid with the guides, whereby the guides are joined by the bearer and other cross member(s).

In a preferred construction the guides are each a channel to receive a leg which is a length of rectangularsection timber slidable in the channel. For the sake of strength it is desirable that the bearer for the deck and likewise the cross member below it are of a cross section which includes at least two portions intersecting at an angle. Channel section is suitable.

It is also preferred that the restraining means for securing legs to guides are independently operable and able to bear on any point along a length of leg thereby enabling individual adjustment of the legs to any point within a range, and thus enabling adjustment to accommodate uneven surfaces.

Preferably the restraining means for securing the legs are clamps which press the deck onto the bearer, and press the legs against the guides. Clamps for legs may take the form of parts pivotally mounted on the connector, being shaped to extend at least partially around a leg fitted to a guide, and pivotally mounted at a position creating a legreceiving gap between the clamp and an associated guide.

This gap varies with pivotal movement of the clamp so that pivotal motion to close the gap can press a leg against a guide and motion to open the gap can release the leg. It is then appropriate for the clamp to be biased to close the gap.

According to another particularly preferred feature of the invention, both the clamps and the guides for the legs are provided with teeth to engage the legs and restrain sliding of the legs relative to the guides.

When each guide is a channel, the teeth provided on the guide are desirably located at the base of the channel. Then the pressure of the clamps on the legs acts to press the teeth on both the clamps and the guides into engagement with the legs.

In a further aspect, the present invention provides an adjustable step for use with a platform having legs, especially legs formed by lengths of timber, which step has a guide region to fit around a leg with clearance to enable the step to be slid along the leg, and restoring means to engage the leg and hold the step under load.

Preferably the restraining means is provided by a pair of zones of the guide region positioned to bear against the leg on opposite sides thereof, one zone being lower than the other and on the same side as the tread, so that load on the tread urges the zones into engagement with the leg. The zones are preferably projecting teeth.

The guide region preferably encircles the leg, for the sake of providing a stronger construction.

In a preferred arrangement the step has a pair of side members which extend from (and may constitute part of) the guide region, and the tread extends between these side members. The guide region preferably defines a passage to receive and encircle a rectangular-section timber leg.

A preferred feature is that the step includes a spring positioned to bear on the leg and bias the said zones into engagement with the leg, even when there is no load on the step. Such a spring, which can be provided by a resiliently deformable tongue projecting obliquely into the passage for a leg, serves to hold the step in place when there is no load on the step. To adjust the step the tread plate can be tilted up, to oppose the spring bias.

An embodiment of the invention will now be described with reference to the accompanying drawings in which Fig. 1 is a vertical cross sectional view of the connector and step, on line I-I of Fig. 3; Fig. 2 is a perspective view of a platform incorporating two connectors and one step; and Fig. 3 is a section on line III-III of Fig. 1.

Referring first to Fig. 1, a connector 2 has a pair of upper channel-section cross members 4 extending between and rigidly welded to leg guides 6 which are each of channel section. These guides 6 are also joined by a pair of lower cross members 8 welded to the guides 6. The lower cross members 8 are longer than the upper cross members 4 so that the guides 6 are each inclined to the vertical at an angle of approximately 7". (It is preferred that the angle lies between 5 and 15 ).

Each guide 6 is provided with a toothed plate 9 (seen at the left hand guide 6 of Fig. 1) welded into the channel section 6 on the base of the channel so that the teeth project downwardly into the channel.

Each guide 6 is provided with a leg clamp 10 including a welded on toothed plate 11 for gripping a leg.

The clamp is generally U-shaped and pivotally attached to the lower cross members 8 by bolts 12. The toothed plate 11 stiffens and strengthens the outer portion 10 of the clamp.

The two leg clamps are connected to each other by a rod 14 and tension springs 16. These bias the leg clamps 10 so as to urge their toothed plates 11 towards the leg guides 6. The pressure of the clamps serves to push both the toothed plates 9 and 11 into engagemnent with the legs.

Each leg clamp 10 has a prolongation 13 at one side which serves as an operating lever. If one of these levers 13 is raised against the spring bias it moves the toothed plate 11 of that clamp away from the respective leg guide 6.

The upper cross members 4 serve as a bearer to support a horizontal deck 28. Clamps 18 for clamping this deck each have an upright web 20 shaped to enter between the channel sections 4 as shown in Fig. 3. From this web 20 extend an upper flange 30 and a shorter lower flange 32. A shaped plate 24 is provided to bear against the underside of the cross members 4.

Each plate 24 is, in use, attached to a flange 32 by means of a bolt 26 fitting into nut 27 welded to the flange 32. These bolts are shown with a conventional hexagon head which is tightened with a spanner. An alternative which could be employed would be bolts with a head akin to a conventional wing nut allowing them to be tightened without use of a spanner.

The support channels 6 receive legs 34 which are clamped in place by the leg clamps 10. The channels 6 are dimensioned to accommodate legs 34 which are rectangularsection timber of the size sold as nominal 4" x 2" planed all round. Such timber is cut to length as desired by the user depending on the intended height at which the platform will be used. The embodiment shown has been found to be suitable for the construction of platforms up to about 5' high. For greater heights it would be desirable to provide further cross bracing between the legs near their bottom ends.

When the appropriate leg clamp 10 is released by pulling upwardly on the lever 13, each leg 34 can slide freely in the channel 6 which receives it. When the leg is in the required position the lever 13 is let go; the biasing spring 16 then biased the teeth, 11 of the clamp against the leg 34 and this then holds the leg securely against the channel section guide 6.

As best seen from Figure 2 a platform is constructed employing two connectors 2 in association with a horizontal deck 28 and four legs 34 fitted to the connectors. The deck conveniently consists of a plank of timber of the size sold as nominal 12" x 2" planed all round. The plank 28 is clamped to the upper cross members 4 of the connectors by means of the clamps 18. These clamps 18 fit around the margins of the plank 28 so that the upper flanges 30 lie on the top surface of the plank at its end portions. The bolts 26 are tightened and this then presses the end portions of the plank 28 down onto the cross members 4.

Because the upper flanges 30 extend over the top margin of the deck plank 28, they hold this down onto the bearer without any fastenings being driven into the plank 28. The entire platform can be picked up by means of the plank 28.

Fig. 2 shows the platform resting on level ground but because each leg can be adjusted independently of the others and moreover can be clamped at any point at which it is positioned, the platform can easily be adjusted to rest with all four legs on ground which is not level. Moreover, this enables the platform to be adjusted to rest on surfaces at different levels such as different steps of a staircase.

A step 36 is fitted onto one of the legs. This step 36 is provided with a horizontal tread plate 28. Side members 40 extend vertically along the sides of the tread plate 38 and are joined by angle section 42 (see Fig. 1) which support the tread plate 38.

The side members 40 are prolonged to form sides of a rectangular guide passage 44 and are integral with a rear plate 46 perpendicular to the side members 40. A cross member 48 extends between the lower edges of the side members 40.

The upper edge of rear plate 46 and the cross member 48 are both provided with teeth 49,50. The rear plate 46 has a resilient tongue 52 welded to it. When a leg 34 is inserted through the guide passage 44, this tongue acts to urge the cross member teeth 50 towards the leg, thus securing the step against the leg 34.

The step is adjustable along the leg 34 by tilting the tread plate 38 upwardly against the bias of the tongue 52. This disengages the teeth, 49,50 from the leg 34. It may bring one angle section 42 into contact with the leg but this angle section is provided with a smooth surface facing the leg and a radiussed upper corner 52 allowing it to slide along the leg. Once the tread plate 38 has been tilted up the step can be slid up or down the leg 34 as desired. When released at the desired point the tongue 52 will bias the teeth 49,50 into contact with the leg so that the step will not slip on the leg. When the user stands on the step the user's weight on the tread plate 38 will urge the teeth 49,50 into even firmer engagement with the leg so that the user's weight serves to keep the step in place on the leg.

The step 36 may be fitted to any of the legs and its position on the leg adjusted as desired when the height of the platform is adjusted. If the platform is set sufficiently high, one or more further steps may be attached to the leg at suitable heights.

The connectors in the embodiment shown in the drawings are fabricated from 14 b.w.g. mild steel plate and the various parts 4,6,8 are welded together giving a rigid construction. A platform assembled with such connectors is able to support the weight of a person even though the legs 34 are held to the guides 6 only by the clamps 10.

The step is also formed principally from 14 b.w.g.

mild steel plate, and is of welded construction. The tread 38 is of expanded metal mesh, giving a good grip. The tongue 52 is of thin steel strip.

The embodiment shown in the drawings is provided to exemplify the invention and modifications to it are of course possible. In particular, alternative materials may be employed depending on the loads to be supported.

Claims (16)

1. A connector for use in constructing a work platform, which connector comprises a pair of guides to receive respective legs slidable in the guides, a bearer for a deck which bearer extends between and is rigid with the two guides, and releasable restraining means to secure a leg releasably to each guide and to secure a deck to the- bearer.

2. A connector according to claim 1 wherein the restraining means for the deck is shaped to extend at least partially over the deck thereby to hold the decks onto the bearer.

3. A connector according to claim 1 or claim 2 wherein the restraining means for the legs are clamps to press the respective legs onto the guides, the clamps and the guides both being provided with teeth to engage the legs for restraining sliding of the legs relative to the guides.

4. A connector according to any one of the preceding claims wherein each guide is a channel to receive a leg which is a length of rectangular-section timber slidable in the channel.

5. A connector according to claims 3 and 4 wherein the teeth on each guide are at the base of the channel.

6. A connector according to any one of the preceding claims further comprising at least one cross member extending between the guides below the bearer for the deck and rigid with the guides.

7. A connector substantially as herein described with reference to the accompanying drawings.

8. A platform comprising a pair of connectors according to any one of the preceding claims, a deck secured to the bearers of the two connectors so as to extend between and join the connectors, and a leg secured to each guide of each connector.

9. A platform according to claim 6 wherein the bearer for the deck and the cross member each have a cross section with portions interesecting at an angle.

10. A connector substantially as herein described with reference to the accompanying drawings.

11. A platform comprising a pair of connectors according to any one of the preceding claims, a deck secured to the bearers of the two connectors so as to extend between and join the connectors, and a leg secured to each guide of each connecter.

12. A platform according to claim 11 further comprising an adjustable step having a guide region to fit around a leg with clearance to enable the step to be slid along the leg, and restoring means to engage the leg and hold the step under load.

13. A platform according to claim 9 wherein the restraining means is provided by a pair of zones of the guide region positioned to bear against the leg on opposite sides thereof, one zone being lower than the other and on the same side as the tread, so that load on the tread urges the zones into engagment with the leg.

14. A platform according to claim 13 wherein the step includes a spring positioned to bear on the leg and bias the said zones into engagement with the leg, the spring being provided by a resiliently deformable tongue projecting obliquely into the passage for a leg.

15. A step according to claim 14 wherein the restraining means are a pair of zones of the guide region positioned to bear against the leg on opposite sides thereof, one zone being lower than the other and on the same side as the tread, so that load on the tread urges the zones into engagement with the leg.

16. A set of two connectors and a step, all substantially as herein described with reference to the accompanying drawings.