GB2292414A

GB2292414A - Load-bearing clamp

Info

Publication number: GB2292414A
Application number: GB9416890A
Authority: GB
Inventors: Ronald Osborne Hampshire
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-08-20
Filing date: 1994-08-20
Publication date: 1996-02-21
Also published as: GB9416890D0

Abstract

A clamp fixed to or integral with an object, e.g. a trailer, caravan, container or mobile home, which holds a leg 1 (with or without attached wheels) such that: it can hold the leg clear of the ground; the leg can be quickly lowered down through the clamp; the weight of the object can be supported by the leg through the clamp; and the leg can be quickly raised clear of the ground; with the only adjustment required to the clamp being the pressing of a release lever to allow the leg 6 to be retracted. As shown the lever 6 directly engages the leg which passes through it when urged to tilt upwards by spring 5. In another embodiment (Fig 5, not shown) the lever carries wedge elements which engage into a fixed sleeve about the leg. <IMAGE>

Description

FAST-ACTION LOAD-BEARING CLAMP This invention relates to a fast-action load-bearing clamp.

There are many instances where objects are supported dear of the ground on legs (with or without attached wheels) and where the height of the object from the ground is adjustable dependent upon the position in which the legs are damped to the object. Examples are ;jockey wheels on caravans and trailers; and legs on the corners of containers and mobile homes.

The adjustment of the legs is usually cumbersome requiring the release and re-tightening of a screw mechanism on the damp; and the ability of the clamp to carry the load transmitted from the leg depends on the tightness of the screw mechanism.

According to the present invention there is provided a fast-action loadbearing clamp comprising a guide through which a leg can slide, a locking device having a form to make an interference fit with the leg in the first position and dear the leg in the second position, resilient means to urge the locking device into the first position thereby restricting movement of the leg relative to the guide, and a release mechanism integral with or acting on the locking device which can be operated to act against the resilient means and move the locking device from the first position to the second position thereby freeing the leg and allowing sliding movement of the leg relative to the guide.

In one element the locking device comprises a lever pivotally mounted on the clamp and having an aperture through which the leg can pass when the lever is in a first generally orthogonal position, but in which the leg jams when the lever is in a second position extended at an acute angle to the leg.

The aperture is preferably oval and the leg preferably has a circular crosssection. The resilient means may be a helical spring surrounding the leg.

In an alternative construction the locking device means include a lever pivotally mounted on the clamp and carrying one or more tapered sleeve or the like mounted on the clamp so that on progressive insertion the wedges increasingly grip the leg.

A specific embodiment of the invention will now be described by way of an example with reference to the accompanying drawing in which : Figure 1 shows in isometric projection, the arrangement of a typical clamp acting on a leg.

Figure 2 shows a side view of the clamp in the locked (first) position where the side support is removed.

Figure 3 shows a sectional view through the clamp in the free (second) position.

Figure 4 shows a sectional view through a clamp in the locked (first) position where the embodiment of the invention uses an alternative resilient means and locking device.

Referring to the drawing the clamp 2 comprises a guide 3 through which leg 1 can slide.

Figure 2 shows the leg 1 restricted from upward movement relative to the clamp 2 by the action of the locking device 4 forming an interference fit against it. The locking device is held in position by the action of the compressed coil spring 5.

Figure 3 shows the clamp of figure 2 released by moving the lever 6 integral with the locking device 4 against the compressed spring 5 thus freeing the locking device from the leg 1 and allowing sliding movement of the leg relative to the clamp 2.

The leg 1 is held off the ground by the frictional forces exerted by the locking device 4 on the leg under the action of the compressed coil spring 5 being sufficient to resist the action of the self weight of the leg and thus hold the leg in position off the ground.

In order to set the leg on the ground, the leg 1 is lowered by applying a force to the top of the leg in the direction Pd sufficient to overcome the action of the spring 5 and frictional resistance of the locking device 4.

Load can then be applied to the clamp causing a reaction in the direction Pu which would tend to move the leg in the upward direction relative to the clamp. The tendency toward upward motion causes the locking device 4 to tighten on leg 1 and prevent any relative movement In order to raise the leg, the load is released from the damp, the release lever 6 is moved downward and the leg pulled up through the clamp 2. The release lever is then released and the leg is held in position by the friction of the locking device under the action of the compressed coil spring.

In figure 4 the lever 6 carries pivoted wedges 4a which surround leg 1 and project into the mouth 4b of a tapering sleeve 4c. As the lever 6 is allowed to rise the wedges 4a progressively enter the sleeve 4c and are wedged against the leg 1 by the inclined surface of the mouth 4b.

A rubber band 5a or the like urges the lever 6 into this locked position.

Depression of the lever 6 substantially withdraws the wedges 4a and releases the leg 1.

Claims

1. A fast-action load-bearing clamp comprising a guide through which a leg can slide, a locking device having a form to make an interference fit with the leg in the first position and clear the leg in the second position, resilient means to hold the locking device in the first position thereby restricting movement of the leg relative to the clamp, and a release mechanism integral with or acting on the locking device which can be operated to overcome the resilient means and move the locking device from the first position to the second position thereby freeing the leg and allowing sliding movement of the leg relative to the clamp.

2. A clamp as claimed in Claim 1 wherein the frictional forces exerted by the locking device on the leg under the action of the resilient means are sufficient to resist the action of the self weight of the leg and thus hold it in position off the ground.

3. A clamp as claimed in Claim 1 or Claim 2, wherein the frictional forces exerted by the locking device on the leg under the action of the resilient means can be overcome by a downward force exerted on the leg and thus enable the leg to be quickly lowered.

4. A clamp as claimed in any one of the claims wherein the layout of the locking device is such as to increase the frictional forces on the leg as the downward load applied to the clamp increases.

5. A clamp as claimed in any one of the preceding claims, wherein the locking device comprises a lever pivotally mounted on the clamp and having an aperture through which the leg can pass when the lever is in a first, generally orthogonal position, but in which the leg jams or interferes when the lever is in a second position extended to an acute angle to the leg.

6. A clamp as claimed in Claim 5, wherein the aperture is oval and the leg is of a circular cross-section.

7. A clamp as claimed in any one of Claims 1 to 4, including a lever pivotally mounted on the damps and carrying one or more tapered wedges located and dimensioned to project into a tapered sleeve or the like mounted on the damp so that the on progressive insertion the wedges increasingly grip the leg.

8. A fast-action load-bearing clamp substantially as hereinbefore described, with reference to figures 1 to 3 or figure 4 of the accompanying drawings.