GB2221277A

GB2221277A - Improvements in shackles

Info

Publication number: GB2221277A
Application number: GB8818041A
Authority: GB
Inventors: Silva Adil Da
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-28
Filing date: 1988-07-28
Publication date: 1990-01-31
Also published as: GB8818041D0

Abstract

A shackle comprises a generally U-shaped bow (10) and a pin (16) for closing the shackle, wherein the pin is of a length to bridge the bow with its respective ends passing wholly through apertures at the respective ends of the arms of the bow, and has at one end a fixed head (20) for preventing passage of said one pin end through the aperture in one arm towards the other arm and has at the other end a lateral protuberance (24), spring loaded laterally outwardly, for preventing passage of said other pin end through the aperture in said other arm towards the first arm except by laterally inward depression of the protuberance. <IMAGE>

Description

Title Improvements in Shackles Field of the invention This invention relates to shackles, which term as used herein refers to shackles of the type comprising a generally U-shaped bow and a pin which connects between the ends of the two arms of the U-shaped bow to close the shackle. Shackles of this type are commonly used on ships, oil rigs and the like for securing ropes and wire cables, for example.

Background to the invention The conventional shackle currently in use has a pin with an eye constituting a head at one end and a screwthreaded portion at the other end. For closing the shackle, this pin is passed through an unthreaded aperture at the end of one arm of the bow and screwed into a threaded aperture at the end of the other arm of the bow. When the pin is unscrewed to open the shackle, the pin can be completely withdrawn and separated from the bow. This separability is disadvantageous in that the pin, in particular, can readily be mislaid or lost, as a result of which the shackle becomes unusable.

It is an object of this invention to provide an improved shackle in which the above-described disadvantage is overcome or at least substantially reduced.

The invention The shackle according to the invention comprises a generally U-shaped bow and a pin for closing the shackle, wherein the pin is of a length to bridge the bow with its respective ends passing wholly through apertures at the respective ends of the arms of the bow, and has at one end a fixed head for preventing passage of said one pin end through the aperture in one arm towards the other arm and has at the other end a lateral protruberance, spring loaded laterally outwardly, for preventing passage of said other pin end through the aperture in said other arm towards the first arm except by laterally inward depression of the protruberance.

In use, the protruberance must be depressed to enable withdrawal of the pin through the aperture in one arm of the bow, thereby to open the shackle. However, the protruberance then serves to prevent withdrawal through the aperture in the second arm, thereby preventing separation of the pin from the bow.

Preferably, the pin extends through the apertures in the bow with just sufficient clearance to permit free rotation of said pin about its axis.

In a preferred construction, the pin has a pair of diametrically opposed spring loaded protruberances. Said protruberances, in the preferred construction, comprise a pair of flat wings or fins, for example generally of triangular shape, each of which has an edge face so orientated that said protruberances tend to be urged further outwards if an axial force is applied to the pin which tends to effect forcible withdrawal thereof without first depressing the protruberances. Conveniently, the wings or fins may be individually mounted for pivotal movement in order to enable protrusion and depression thereof, and may be spring loaded by a common spring, for example an arrow-head Strip sorting, acting directly between said two wings or fins.

A shackle in accordance with the invention finds application not only on ships and oil rigs but also in many other fields including construction, forrestry work, climbing, boating and sailing to give but a few examples.

Description of embodiment A practical construction of shackle in accordance with the invention is shown diagrammatically in the accompanying drawings, in which: Figure 1 is an elevational view of a closed shackle; Figure 2 is a front view of the shackle pin, showing the interior as if the pin was transparent; Figure 3 is a side view of part of the pin; and Figure 4 is an end view of the pin.

The illustrated shackle comprises a generally U-shaped bow 10 with respective arms 12 and 14, together with a pin generally referenced 16.

The bow and the pin are made of hard metal, such as stainless steel or drop forged steel, and the shackle may be nade in a range of sizes from about 5 cm length, through about 12 cm length for an 8 tonne load up to about 45 cm length for a 100 tonne load.

The bow has two circular and aligned apertures through swellings 18 at Lne ends of its respective arms 12, 14.

The pin 16 which closes the shackle is of a length fully to bridge the shackle with its respective ends passing totally through the apertures in the bow. One end of the pin has a fixed head 20, which may take the form of diametrically opposed projections as shown but could be any other desired form of head, including an eye, for example.

At the other end the pin 16 is slotted, as indicated at 22, to accommodate a pair of generally triangular flat wings 24 with tails, each pivotally mounted by a rivet 26.

An arrow head spring of spring steel strip 30 engages directly between the two wings to urge the two wings laterally outwards of the pin. However, by application of a squeezing pressure to the wings 24, as indicated by the arrows 28, the wings may be depressed to be wholly disposed, or at least substantially wholly disposed, within the cross-section of the pin.

In the closed condition of the shackle shown in Figure 1, the pin 16 can rotate freely, which is advantageous in some usages of the shackle, and in particular enables it more readily to be used as a snatch block. It is also to be noted that the wings 24 present edge faces 30 which inhibit depression of the wings if an axial force acts on the pin to force withdrawal thereof without first depressing the wings.

Squeezing together of the wings 24 enables the pin to be withdrawn through the aperture in one arm (the arm 14 as illustrated) of the block, but the pin does not separate from the block due to automatic redeployment of the wings which occurs when the pin has been withdrawn clear of this first aperture, thus preventing withdrawal through the second aperture (in the arm 12 as illustrated), except as a deliberate action.

Various modifications of the above-described and illustrated arrangement are possible within the scope of the invention hereinbefore defined.

Claims

Claims:

1. A shackle comprising a generally U-shaped bow and a pin for closing the shackle, wherein the pin is of a length to bridge the bow with its respective ends passing wholly through apertures at the respective ends of the arms of the bow, and has at one end a fixed head for preventing passage of said one pin end through the aperture in one arm towards the other arm and has at the other end a lateral protruberance, spring loaded laterally outwardly, for preventing passage of said other pin end through the aperture in said other arm towards the first arm except by laterally inward depression of the protruberance.

2. A shackle according to claim 1, wherein the pin extends through the apertures in the bow with just sufficient clearance 0 permit free rotation of said pin about its axis.

3. A shackle according to claim 1 or 2, wherein the pin has a pair of diametrically opposed spring loaded protruberances.

4. A shackle according to claim 3, wherein the protruberances comprise a pair of flat wings or fins each of which has an edge face so orientated that said protruberances tend to be urged further outwards if an axial force is applied to the pin which tends to effect forcible withdrawal thereof without first depressing the protruberances.

5. A shackle according to claim 4, wherein the wings or fins are of generally triangular shape.

6. A shackle according to claim 4 or 5, wherein the wings or fins are individually mounted for pivotal movement in order to enable protrusion and depression thereof.

7. A shackle according to claim 4, 5 or 6, wherein the wings or fins are spring loaded by a common spring acting directly between said two wings or fins.

8. A shackle according to claim 7, wherein the spring is an arrow-head slip spring.

9. A shackle substantially as herein described with reference to, and as shown in, the accompanying drawings.