GB2078844A - Fastening device - Google Patents

Abstract

A fastening device for tightening, for example, a chain, around a load and holding it in its gripping position comprises a base block 2 with an attachment point 6 for one end of the chain at one end and a pivot 4 for an intermediate lever 12 at the other. This lever supports a handle 20 at pivot 18, offset from the longitudinal axis of lever 12 through pivot 4. To tighten the chain handle 20 is pivoted anti-clockwise from the phantom line position 20' to meet abutment 16 on lever 20 and to cause that to pivot as well into the solid line position shown. The other end of the chain is attached to point 30 on handle 20 and, during this movement, point 30 moves over-centre so that in the final position shown tension in the chain tends to hold both handle 20 and lever 12 in the shut position. <IMAGE>

Description

SPECIFICATION Fastening device This invention relates to a fastening device.

In particular, the invention has particular but not exclusive reference to such a device for use as a connection in a flexible member which it is desired to thighten. A fastening device of this kind finds application in binding loads transported on carriers, where it is important to effect temporary and releasable securement of the load to the carrier. The load must remain stable during transit and its release should be easily carried out without danger to personnel or equipment. When heavy and awkward loads are to be transported, the binding which is generaliy flexible possesses a considerable tension and accordingly the generation and release of such tension can imperil the personnel operating the fastening device.

A conventional fastening device used for this purpose comprises a link block to which at one end the binding is in use affixed and to which at the other there is pivotted a locking member incorporating an operating handle. The locking member also has a connection for the binding which with the fastening device so connected forms a loop which can circumscribe a load. In order to tension the binding, the locking member is pivotted towards the link block until the connection for the binding on the member passes over centre with respect to the pivot. The tension in the binding, therafter, keeps the locking member in a locked position in relation to the link block.

The tension in the binding is very often of the order of tons and usually a lever has to be applied to the handle of the locking member in order to allow a sufficient force to be generated to ensure locking.

The release of the fastening device is achieved in reverse manner, but then force used should be at least equal to that applied during locking, otherwise the binding will be released instantaneously. The stored energy can cause the lever to fly-off at a very high speed and in confined spaces particularly the danger to personnel and equipment is acute. A further potential danger is that the point of balance of the load secured by the binder may have moved during transit. The release of the binder may cause the load to topple over onto an unsuspecting operative. An object of the invention is to provide an improved fastening device which will enable safer operation to be achieved.

Accordingly the invention provides a fastening device for use on bindings for transportable loads, the device including a link block, a first connection point at or towards one end of the link block, a first pivot point at or towards the other end of the link block, an intermediate link pivotted to the link block at the first pivot point, an operating lever connected to the intermediate link at a second pivot point offset in relation to the first pivot point, the lever being movable between a released position and a locking position such that during movement, the second pivot point on the lever passes through an overcentre position with respect to the first pivot point, and a second connection point located on the lever whereby upon movement of the lever, the second connection point passes through over-centre positions with respect to the first and second pivot points.

Conveniently, the link block is in the form of a yoke at the one end of which is located the first pivot point to which the intermediate link also of yoke form is attached. The intermediate link moves pivotally within the link block and carries the second pivot point at a position spaced from the first pivot point.

The second pivot point is located on a centre line offset from a centre line passing through the first pivot point extending lengthwise of the link.

The lever conveniently has a handle leading to a bifurcated position which is pivotally attached to the link at the second pivot point The second connection point may conveniently be located adjacent the second pivot point on a centre line offset from that of the second pivot point.

The first and second connection points may be of any desired form to accommodate various types of connector, for example hooks and eyes, chains etc., employed for the relevant binding.

By way of example only, one form of fastening device according to the invention is described below with reference to the accompanying drawings in which Figure 1 is a wide elevation; and Figure 2 is a plan view.

Referring to the drawings, a fastening device 1 comprises a link block 2 having a first pivot point 4.at one end thereof and a first connection point at the other end in the form of an eye 6 screwed into a bridge piece 8 of the block 2 which is in yoke form with two limbs 10 connected at the one end by the bridge piece 8. An intermediate link 12 has two spaced apart side plates 14 connected at one end of the link by a cross member 16, the side plates 14 being pivotted at 4 to the links 10 of block 2.

A second pivot point 18 is located intermediate the first pivot point 4 and the member 16 and at this point is pivotted a lever 20. The lever 20 has a handle 22 which joins a fork 24, each side 26 of which is pivotted to the side plates 14 at 18.

The pivot point 18 lies on a centre line offset from the centre line of pivot point 4 as can be seen in Figure 1.

A second connection point 30 is provided on the lever 20 and has a centre line offset from that of point 18 and point 4 as shown. A connector 31 may be attached (see Figure 2) to the point 30.

In operation, the fastening device 1 is used for binding loads on transporters, the binding being for example a length of chain only the centre lines of which are shown at A and B. One end of the chain is connected to the eye 6 and the other to the connection point 30. When it is desired to tighten the binding chain to secure a load, the lever 20 and link 12 are opened to a maximum degree and the chain attached. The lever 20 is moved anticlockwise as viewed in Figure 1 until contact is made with cross member 16. Thereafter the lever 20 and link 12 act in unison. Lever 20 is further rotated auto-clockwise applying tension to chain via point 30 until point 30 passes over-centre in relation to eye 6, and points 18 and 4 and link 12 contacts link block 2.

Once the lever 20 is in the locked position, the binding chain, centre line B, keeps the lever 20 down as can be seen since the line of action of the tension on the chain is below the pivot points 4 and 18. A locking pin (not shown) may advantageously be used as an added safety measure, the pin extending through the link block, the link and the lever.

When release is required, the reverse occurs whereby an operative moves the handle 22 in a clockwise direction as viewed in Figure 1, the connection point 30 thereby moving through the over-centre position with regard first to point 18 and then to point 4. Thereafter, the lever 20 can be moved to pivot the intermediate link 12 so that the pivot point 18 itself is moved through the overcentre position of point 4, thus releasing the loading in the chain.

It will be appreciated that as the over-centre positions are passed, an increase in tensions results.

However, the radius dimension as between points 30 and 18 determines the degree of tension experienced as the over-centre position is passed.

By employing the intermediate link 12, two overcentre positions are passed by the connection point 30 thus giving a controlled increase or decrease in tension in the chain depending on whether locking or release is taking place. In tests it has been shown that halfthe chain tension is released by moving the lever 20 from the locked position to a vertical position. Thereafter further movement effects release of the remaining tension.

While the use of extensions to the handle 22 may be needed in some cases, its use may be eliminated in others. Even where its use is required, the operative can view with a greater degree of safety the effect of the more controlled manner of load release available through use of the invention as opposed to the use of conventional fastening devices.

It will be understood that modification to the invention can be effected without departing from the principle. For example, the device could be modified to provide that a gradual increase in tension is achieved by giving sequential operation to the link 12 and lever 20 during application of the tension. In this instance, the link 12 would first more into a locked position in relation to block 2 and thereafter the lever 20 would be moved into a locked position thus giving a stepped application in loading.

Claims (8)

1. A fastening device for use on bindings for transportable loads, the device including a link block, a first connection point at or towards one end of the link block, a first pivot point at or towards the other end of the link block, an intermediate link pivotted to the link block at the first pivot point, an operating lever connected to the intermediate link at a second pivot point offset in relation to the first pivot point, the lever being movable between a released position and a locking position such that during movement, the second pivot point on the lever passes through an over-centre position with respect to the first pivot point, and a second connection point located on the lever whereby upon movement of the lever, the second connection point passes through over-centre position with respect to the first and second pivot points.

2. Afastening device according to Claim 1 in which the link block is in the form of a yoke.

3. Afastening device according to claim 1 or2 in which the intermediate link is in the form of a yoke.

4. A fastening device according to claims 1, 2 and 3 in which the intermediate link is movable pivotally within the link block and carries the second pivot point at a position spaced from the first pivot point.

5. A fastening device according to any one of the preceding claims in which the second pivot point is located on a centre line offset from a centre line passing through the first pivot point extending lengthwise of the link.

6. A fastening device according to any one of the preceding claims in which the lever has a handle leading to a bifurcated portion which is pivotally attached to the intermediate link at the second pivot point.

7. Afastening device according to any one of the preceding claims in which the second connection point is located adjacent the second pivot point on a centre line offset from that of the second pivot point.

8. Afastening device for use on bindings for transportable loads substantially as herebefore described with reference to Figures 1 and 2.