GB2200319A - Restraint and holding device - Google Patents

Abstract

In a holding device, the restrained object 3 is held by an upper support 2 and a lower support 5. One of these supports is constructed with a concave profile, and the opposing support is constructed of a flexible material, thereby allowing a conforming grip. The two supports 2 and 5 are offset slightly in a horizontal direction such that when the object 3 is placed upon the lower support 5, the object tends to rotate about that support which causes the restrained end 4 of the object to engage the upper support 2. The weight 6 of the object and the applied forces 1 act together to increase the strength of the restraint, by increasing the contact forces at the supports 2 and 5. Both supports may be flexible. <IMAGE>

Description

RESTRAINT AND HOLDING DEVICE This invention reiates to equipment for the restraint and holding of materials.

The safe restraint of materials for sawing, for example, is of considerable importance in industrial and domestic applications. The advent of high powered portable cutting equipment, such as hand held circular saws and chain saws, has led to the increased use of these devices in less than ideal circumstances, frequently by relatively inexperienced operators.

An important feature of the design of holding devices for sawing operations is the suitability for prolonged periods of use without inducing unnecessary fatigue in the operator.

Factors reiating to damage to the saws themselves under everyday conditions of use are also significant. For example the operation of chain saws near ground level can frequently lead to the saw striking the ground and thereby blunting the cutting edges.

The design of equipment for the restraint of objects of consistent shape and size under closely controlled conditions is usually a relatively straightforward matter. However, the high incidence of accidents with portable saws indicates the inadequacy of existing equipment for the restraint of irregularly shaped objects under field conditions.

Currently available equipment falls into two categories:- 1) Benches and clamps.

At best these systems consist of the rigid clamping of the material to be restrained onto a bench or other suitable surface, using special ised clamps or vice jaws.

At worst the bench and clamp may comprise a piece of wood upon which the operator's knee holds the material.

The more ideal versions of this type of restraint are often unsuitable for rapid use, and may be entirely unsuitable for irregular shapes and sizes of material, especially under field conditions.

This type of problem frequently induces the operator to take risks with his own safety and that of bystanders, as well as that of the machinery.

2') Sawhorses and rests.

The traditional form of sawhorse was evolved to suit hand operated saws, and is entirely unsuitable for use with power tools, since the restrained item must be moved repeatedly in order to prevent the jamming of the saw which occurs when the cut is made between two supports.

The essential feature of a desirable form of sawhorse is that the restrained item should be supported at one end only, thereby preventing the jamming problem mentioned above.

Currently available forms of these types of restraint provide only limited holding and adaptability, and do not adequately satisfy safety criteria in these respects.

The background material as outlined above also applies to many as-pects of the restraint of awkwardly shaped objects undergoing procedures other than sawing, such as pipework manipulations, welding of complex structures etc.

The subjects of this invention provide a method of restraint and holding of an object of any crosssectional shape.

The restrained object is held by an upper support and a lower support.

One of these supports is constructed with a concave profile, and the opposing support is constructed of a flexible material, thereby allowing a conforming grip.

The two supports are offset slightly in a horizontal direction such that when the object is placed upon the lower support, the object tends to rotate about that support which causes the restrained end of the object to engage the upper support.

The weight of the object and the applied forces act together to increase the strength of the restraint, by increasing the contact forces at the supports.

Three specific embodiments of this invention will now be described by way of example. In each case the object to be restrained is a log, and the operation to be performed is cutting with a power saw.

Other objects and procedures may be applied in a similar fashion.

Example 1.

Reference is made to the attached diagrams in which:- Fig. 1 shows a view of a log restrained by the supports and the relevant forces acting upon the log.

Fig. 2 shows a schematic view of a log restrained by a flexible lower support and a concave upper support.

Fig. 3 shows a view of a practical version of this form of the invention.

Referring to Fig. 1 ,the restrained end 4 is carried by the lower support 5. The tendency of the weight 6 and the optional applied forces 1 to rotate the log about the lower support 5 causes the end 4 of the log to rotate upwards and engage on the upper support 2. This leaves the end 7 cantilevered out in free space, and cuts may now be made with the saw, which itself induces applied forces 1.

The restraint of the log is achieved in a self-adapting manner by the use of flexible elements as the upper or lower supports of Fig. 1.

Referring to Fig. 2 in this case the lower support 5 is formed by the flexible element. Any size or shape of log 3 self-locates in the concave upper support 2 as the log pivots on the flexible lower support 5, the length of which is coarsely adjustable to suit the size of log.

A practical version of this form of the device is shown in Fig. 3, where the upper support 2 takes the form of an inverted "V"-shape, the lower support 5 is flexible and the insertion of horizontal members into the holes 8 prevents the whole assembly tilting over when a log is in position.

Example 2.

Reference is made to the attached diagrams in which: Fig. 4 shows a schematic view of a log restrained by a flexible upper support and a concave lower support.

Fig. 5 shows a view of a practical version of this form of the invention.

In conditions where the mechanical lifting of heavier logs is required the system as described in Example 1.

may be inverted (see Fig. 4 ).

The lower support 5 is rigid in order to facilitate its forcible insertion beneath the end 4 of the log. The flexible upper support 2 then takes the upward thrust of the end of the log as the whole system lifts from the ground.

The effective length of the flexible upper support is made coarsely adjustable to accomodate logs of various sizes. A practical form of the device is shown in Fig.

5.

The log 3 is first engaged by forcible insertion of the rigid lower support 5 under the end of the log The flexible upper support 2 is then placed in position and its length coarsely adjusted to lie over the upper surface of the log.

The fixed end of the device 9 may be constructed to suit any lifting device such as a tractor three point linkage, and with such a lifting device attached to 9 the log may be mechanically lifted and is thereby also restrained.

Example 3.

Reference is made to the attached diagram Fig. 6. which shows a schematic view of the restraint and holding device configured with both gripping elements being flexible.

In some conditions it may be necessary to have both upper and lower supports flexible, in which case an arrangement of the form of Fig. 6 might be required.

In this example the log 3 is restrained by the action of its weight on the flexible lower support 5, thereby causing the upper flexible support 2 to engage the upper surface of the log.

The end 9 of the device may be constructed to suit any form of attachment to a lifting system or to a platform for free-standing on the ground in a fashion similar to that in Example 1.

Claims (4)

CLAIMS:

1) A restraint and holding device which uses the weight of the restrained object and optional additional forces to combine together to increase the strength of the restraint, and wherein the grip self-adjusts to conform with the cross-sectional shape of the restrained object in the gripping region.

The device achieves this by the use of a flexible element as one of the gripping elements and an offset between this and the opposing gripping element, which is provided with a concave surface.

2) A restraint and holding device as claimed in Claim 1 wherein the upper gripping element is flexible and the lower element is rigid and concave.

3) A restraint and holding device as claimed in Claim 1 wherein the upper gripping element is rigid and concave and the lower element is flexible.

4) A restraint and holding device as claimed in Claim 1 wherein both gripping elements are flexible.