GB2238978A

GB2238978A - Self adjusting gripping device

Info

Publication number: GB2238978A
Application number: GB8928462A
Authority: GB
Inventors: Timothy Fogden
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-12-16
Filing date: 1989-12-16
Publication date: 1991-06-19
Also published as: GB8928462D0

Abstract

A work holding device will grip lengths of material of various sections near to one end, having automatically adjusted itself to size. For instance where it is used for holding lengths of wood in a horizontal position for sawing pieces approximately 120 cm long are quickly held in sizes anything up to approximately 30 cm in diameter, near to one end so that there is plenty of clearance for sawing into logs. A post 1 carries a fixed lower gripper 3 and a self-adjusting slidable upper gripper 4 which is automatically locked to the post by a twisting action and friction. <IMAGE>

Description

SELF ADJUSTING GRIPPING DEVICE This invention relates to a device which adjusts automatically to grip lengths of material of various cross sectional shapes and sizes.

The need for such a device, originates from the requirement to hold lengths of wood of various shapes and sizes securely somewhere near to one end for sawing into logs, without constant adjustment and repositioning of the timber being sawn.

According to the present invention, there is a rectangular post carrying an upwardly inclined lower jaw. The self adjusting downwardly inclined upper jaw, is mounted onto another rectangular box section which slides over the post. As the jaws are not vertically in line, when they engage the material to be held, a twisting moment is induced into the upper jaw which locks it through friction to the post holding the lower jaw. In this way timber or other materials of various sizes are held appronmately horizontally somewhere near to one end in a vice like grip. Adjustment to size is entirely automatic because the upper jaw simply slides down the post until contacting the material to be held.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows in perspective, the self adjusting gripping device holding a length of timber for sawing into logs.

Figure 2 shows the grips opened ready to accept a length of timber.

Figure 3 illustrates the method by which the grips self adjust and hold a length of timber approximately horizontally.

Referring to the drawing, the self adjusting locking device comprises an upright rectangular post 1 supported on stand 2 and carrying lower grip 3. The upper self adjusting gripper 4, is attached to a rectangular box section which is free to slide on the post. A small ledge 5 near the top of the post holds the upper grip in its raised and open position.

continued / A length of timber for sawing is placed onto the lower grip towards one end such that the last log can be cut to a similar length to the rest. By releasing the upper grip from its ledge, it is lowered until arrested by the length of timber according to its diameter.

As the upper and lower grips are not vertically opposed, when the timber is no longer supported by hand, a twisting moment is imposed on the upper grip, such that the rectangular section upon which it is carried, locks to the post by friction. The timber is then automatically held in an approximate horizontal plane for unobstructed sawing. When sawing has been completed the upper grip is then raised by the handle 6, until it latches onto the ledge 5 near to the top of the post, ready to accept the next piece of timber.

Claims

1. A self adjusting gripping device for holding materials at or near to the horizontal somewhere near to one end.

2. A self adjusting gripping device which has one normal and one inverted VEE grip.

3. A self adjusting gripping device which relies upon a twisting action to impose sufficient friction to create a positive vertical hold on the upper self adjusting grip.

4. A self adjusting gripping device which has its upper and lower grips staggered in the vertical plane to create a twisting moment on the self adjusting one sufficient to hold it in position by friction.

5. A self adjusting gripping device which has a ledge let into the post to hold the self adjusting grip in its raised and open position.

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6. A self adjusting gripping device,the post of which is free standing.

7. A self adjusting gripping device that will hold various materials at or near to the horizontal providing the grips are of material that will not readily slide on the material to be held. This is necessary to impose the twisting moment described in claim 3.