GB2166412A

GB2166412A - Trench sheet clamp

Info

Publication number: GB2166412A
Application number: GB08427960A
Authority: GB
Inventors: Peter Andrew Ross Mccormick
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-11-05
Filing date: 1984-11-05
Publication date: 1986-05-08
Also published as: GB8427960D0; GB2166412B

Abstract

A trench sheet clamp for use with sheets shoring up the sides of excavations, comprises two generally parallel legs (14, 24), one of which is pivotable relative to the other so that by such pivotal displacement the open jaw end of the clamp is opened up so that the clamp can more easily be lowered over the upper edge of a trench sheet. The shorter leg (24) is preferably the pivotable leg. A fastening device (34, 36) is fitted through holes (18, 28) in the legs and through the sheet to secure the clamp in place. A shackle (20) is provided to enable the clamp and trench sheet to be lifted. <IMAGE>

Description

SPECIFICATION Heavy-duty clamp This invention relates to heavy-duty clamps, and is particularly concerned with what are known as trench sheet clamps.

When carrying out excavations and the digging of trenches and holes in the ground it is often necessary to shore up the sides of the excavation by metal sheets which are driven into the ground.

Problems can arise when the excavation is to be refilled and the trench sheets have to be removed.

These trench sheets are conventionally provided with one or more holes adjacent to the top edge, so that a clamp can be fitted to the trench sheet, through the hole, whereafter a crane or other lifting device can be used to raise the trench sheet from the excavation. The conventional trench sheet clamp is a bifurcated clamp having two substantially parallel legs. The clamp is pushed down over the projecting upper edge of the trench sheet with one leg on each side of the trench sheet, and a securing pin is then fitted through aligned holes in the legs and through the hole in the trench sheet in order to secure the clamp in position for subsequent lifting.However, in practice, the upper edges of the trench sheets often become damaged and bent when they are hammered into the ground, and this makes it difficult or impossible then to slide the conventional trench sheet clamps down over the trench sheet so that it can be secured thereto.

It is an object of the present invention to provide an improved heavy-duty clamp, particularly suitable for use as a trench sheet clamp, which overcomes or at least substantially reduces the problems inherent in the use of the conventional type of clamp referred to above.

Broadly in accordance with the present invention there is prevented a heavy-duty clamp comprising two legs which are arranged to be generally parallel in use, fastening means between the two legs serving additionally to locate the clamp on an article to be lifted, wherein at least one of the legs is arranged to be displaceable to define an open jaw at the end of the clamp where the fastening means is located.

In a preferred embodiment of the invention, one leg of the clamp is arranged to be pivotable relative to the other leg.

By providing the clamp with means whereby the legs can be opened up from the usual parallel state it is then possible more easily to lower the clamp over a distorted upper edge of a trench sheet and to position it in alignment with the trench sheet hole. The fastening means can then be fitted through the hole and the clamp legs returned to a position as close to parallel as the circumstances will permit.

One presently preferred embodiment of clamp in accordance with the invention will now be described in detail by way of example and with reference to the accompanying drawing which is a schematic side view of the clamp.

Referring now the drawing, the trench sheet clamp shown therein comprises two main components, each of which defines one leg of the clamp.

The first component, indicated generally at 10, comprises an upper block portion 12 and a downwardly extending, longer side leg 14. This leg 14 is rectangular when viewed in front elevation and is provided on its inner face with a rectangular facing block 16. This can conveniently be welded to the leg 14. A cylindrical hole 18 is provided through the leg 14 and the facing block 16 towards the bottom of the leg. The upper block portion 12 is also provided with a hole therethrough to receive the pin of a shackle which is indicated generally at 20.

The other main component of the clamp is indicated generally at 22 and comprises a shorter side leg 24 which has the same width dimension as the opposing leg 14 and which is similarly provided with a facing block 26. This facing block 26 and the leg 24 are provided with a hole 28 therethrough in alignment with the hole 18 through the longer side leg 14. An internally screw-threaded nut 30 is welded on to the outer face of the shorter side leg 24 in alignment with the hole 28. The upper end of the shorter side leg 24 is bifurcated with arms extending one on each side of the upper block 12. A pivot bolt 32 is fitted through the bifurcated arms of the leg 24 and through a hole in the upper block 12, so that the shorter side leg 24 is freely pivotable relative to the longer side leg 14 about the axis of the pivot bolt 32.The shorter side leg 24 is preferably pivotable through an angle of about 75". It will be noted from the drawing that the axis of the pivot bolt 32 is slightly offset relative to the axis of the shackle pin. This is of assistance in achieving the desired freedom for pivotal movement of the shorter side leg.

A connecting bolt 34 which is provided with an operating handle 36 is connected by a retaining chain 38 to the upper block 12 and is arranged to pass through the holes 18 and 28 in the two legs and be received in threaded engagement in the nut 30.

In use, with the connecting bolt 34 removed, the shorter side leg 24 can be pivoted upwards and away from the longer side leg 14 and the clamp can then be iowered down over the top of a trench sheet until the hole 18 in the longer side leg 14 is aligned with the hole in the upper portion of the trench sheet. With the clamp so positioned the shorter side leg is dropped into position and the connecting bolt 34 is passed through hole 18, through the hole in the trench sheet, through hole 28 and is screwed into the nut 30. The trench sheet is then positioned between the two facing blocks 16 and 26. The clamp, together with the trench sheet, can then be lifted using the shackle 20 and appropriate lifting means connected to the shackle.

Although the clamp shown in the drawing is designed with the shorter side leg pivotable relative to the longer side leg, it would alternatively be possible with the scope of the invention to have both legs pivotably mounted relative to a common top block carrying the shackle. However, the illustrated embodiment is preferred for simplicity.

Additionally, any other convenient securing means may be used to couple the two legs together and to the top of the trench sheet or other item to be lifted. A screw-threaded nut and bolt is preferred, again for simplicity and ease of operation.

Claims

1. A heavy-duty clamp comprising two legs which are arranged to be generally parallel in use, with fastening means between the two legs serving additionally to locate the clamp on an article to be lifted, wherein at least one of the legs is arranged to be displaceable to define an open jaw at the end of the clamp where the fastening means is located.

2. A clamp as claimed in claim 1, in which one leg of the clamp is pivotable relative to the other leg.

3. A clamp as claimed in claim 1 or 2, in which the two legs are of unequal length, and the shorter leg is pivotable relative to the longer leg.

4. A clamp as claimed in any preceding claim, comprising a block portion from which the two legs extend, the block portion being provided with shackle means comprising a first pivot pin, and a second pivot pin being provided for pivotal movement of one leg of the clamp, with the axis of said second pivot pin being offset relative to the axis of the first pivot pin.

5. A clamp as claimed in any preceding claim, in which one leg of the clamp is pivotable through an angle of the order of 75".

6. A clamp as claimed in any preceding claim, in which the two legs are each provided with facing blocks at the open jaw end of the clamp, the facing blocks being provided in opposing relationship on the mutually facing surfaces of the respective legs.

7. A heavy-duty clamp substantially as hereinbefore described with reference to the accompanying drawing.