GB2213862A

GB2213862A - Resiliently biased shackles

Info

Publication number: GB2213862A
Application number: GB8729330A
Authority: GB
Inventors: David Francis Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-12-16
Filing date: 1987-12-16
Publication date: 1989-08-23
Anticipated expiration: 2007-12-16
Also published as: GB2213862B; GB8729330D0

Abstract

A shackle comprises first and second plastics mouldings (1 and 2) which are assembled together and can be rocked relatively to each other. The first moulding (1) has a hook formation (3) with a mouth (4) and the second moulding (2) has an openable closure (9) for the mouth. The second moulding (2) also has a retaining loop (10) with a gap (11) in it through which a ring or other anchorage can enter. A limb (12) of the loop, adjacent to the gap (11) serves as a spring to urge the closure (9) to its closed position The first moulding (1) has spaced walls (6) with an abutment (7) and a stop (8) extending between them. During assembly the abutment (7) snaps through the gap (11) and is shifted into rocking engagement with a part-cylindrical recess (13) in the loop (10). The tip of the spring limb (12) engages the stop (8) and enters into a recess (16) in the stop to prevent easy disassembly of the shackle. <IMAGE>

Description

SHACKLES This invention relates to spring-loaded shackles of the kind having a hook portion with a mouth and a spring-loaded closure which normally closes the mouth but can be opened against the action of spring-loading.

Such shackles may, for example, be releasably attached. to loops or rings on straps or cords, or may be used for releasable attachment directly to elongate members such as straps, cords or bars.

Such shackles may be used for releasably attaching reins to harnesses for small children, or for any of a wide range of other purposes. They may for example be used for attaching leads to dog collars, and in a variety of applications in boats, climbing gear and other equipment for outdoor use.

The aim of the present invention is to provide an improved form of shackle designed to be manufactured in plastics material and which may be assembled simply and inexpensively.

From one aspect the present invention consists in a shackle comprising first and second plastics mouldings which are assembled together and can be rocked relatively to each other, the first moulding having a hook formation with a mouth and the second moulding having an openable closure for the mouth, one of the mouldings also having a portion constituting spring means which, when stressed, applies a force to the other moulding and urges the mouldings towards a closed position, in which the closure closes the mouth of the hook formation, it being possible to rock the mouldings, against the action of the spring means, to an open position, in which the closure no longer closes the mouth of the hook formation.

From a second aspect the present invention consists in first and second mouldings that can be assembled together to form a shackle in accordance with the first aspect of the present invention.

In a preferred construction the spring means forms at least part of a retaining loop with a gap in it, said other moulding having blocking means which permanently closes that gap, the arrangement being such that before the mouldings are assembled the retaining loop can engage a ring or other anchorage, a portion of the ring or other anchorage being passed through said gap into the interior of the loop, but the gap being closed by the blocking means on subsequent assembly of the mouldings.

In a preferred form of shackle it is the second plastics moulding that includes the retaining loop while the first plastics moulding includes the blocking means. Nevertheless, the reverse arrangement remains within the scope of the present invention, that is an arrangement in which it is the first plastics moulding that includes the retaining loop and while the second plastics moulding includes the blocking means.

The spring means preferably comprises a limb of the retaining loop adjacent to the gap. One or more barb-like formations is preferably provided between the gap and the other end of the loop further from the gap, the arrangement being such that a portion of a ring or other anchorage that enters the loop through the gap can be snapped past the barb-like formation or formations, to a place at or adjacent to said end of the loop, where it is retained by the formation or formations and is thereby prevented from interfering with the operation of the spring means.

The mouldings are preferably such that they can be assembled by snap-action. The mouldings may be such that they can also be disassembled by snap-action and can be repeatedly assembled and disassembled at will.

Preferably, however, the mouldings are such that after assembly by snap-action they cannot be disassembled by snap-action; indeed, the arrangement may be such that it is virtually impossible to disassemble them with out their being damaged or destroyed.

The hook formation is preferably formed with a recess or slot opposite the mouth, while the closure is preferably so shaped that it extends into that recess or slot, the closure moving further into the recess or slot when the shackle is moved from its closed to its open position. The closure is preferably so shaped that, when the shackle is in its closed position, it presents a concave or recessed abutment face to the interior of the hook formation. Consequently, in use, if a ring, for example, is engaged by the hook formation and is forced against the closure, it tends to be guided into the concavity or recess in the abutment face rather than into a position in which it could wedge between the closure and an adjacent part of the hook formation and thus lead to damage or to the hook formation being forced open.

The hook formation is preferably formed with a groove adjacent to its mouth, part of the closure entering that groove when the shackle is in its closed position. The purpose of this is to increasing the resistance to forces applied to it in a direction normal to the planes in which it moves when moving to and fro between open and closed positions.

One of the mouldings is preferably formed with an abutment which fits into a complementary recess formed in the other moulding, the abutment and recess together constituting a bearing and in use the mouldings rocking about the axis of that bearing, the arrangement being such that during assembly the entry of the abutment into the recess requires resilient deformation of the spring means which finally snaps back to retain the abutment in the recess.

An embodiment of the invention will now be described in more detail, by way of example, wit?- reference to the accompanying drawings, in which: Figure 1 is a side view of a shackle in accordance with the present invention, Figure 2 is a perspective view of the shackle, Figures 3 and 4 are side views of first and second mouldings, respectively, of the shackle, Figure 5 is an underneath plan view of the first moulding, and Figure 6 is a plan view of the second moulding.

The shackle illustrated in Figures 1 and 2 consists of an assembly of a first plastics moulding 1 and a second plastics moulding 2. Each of the mouldings is made from a suitable plastics material. The mouldings can be made from different materials but are conveniently made from the same material. At least the second moulding 2 must be made from a resilient material. In one specific type of shackle both mouldings are made from an acetyl resin.

The first moulding, 1, has a hook formation 3 with a mouth 4. Opposite the mouth is a through slot 5, which extends to that end part of the moulding remote from the hook formation and thus divides that part of the moulding into two spaced walls 6. The walls are bridged by a cylindrical abutment 7, which forms part of a rocking bearing, and also by a stop 8. In a modification (not illustrated) the stop merges with an adjacent part of the rocking bearing.

The second moulding, 2, is at one end formed with a cloture 9, which is sufficiently narrow to enter between the slot 5 in the first moulding. At the other end the second moulding is formed with a retaining loop 10 which is provided with a gap 11 near one end. A portion 12 of the loop adjacent to the gap is in the form of a limb and is of a cross-section thinner than that of the remainder of the loop. The portion or limb 12 can thus act as a spring. That end portion of the loop adjacent to the gap is formed with a part-cylindrical recess 13 which is complementary to the abutment 7. The abutment 7 and recess 13 together constitute a rocking bearing, as described below. An upstanding portion 14 of the second moulding 2, between the closure 9 and the recess 13, constitutes an operating bar. The bar is illustrated as being transversely grooved to provide a good grip for the user's finger or thumb. If desired the bar may be of increased width or thickness to provide a larger area for engagement by the user's finger or thumb (though this modification is not illustrated) . It is necessary, however, to ensure that the increase in thickness applies only to those parts of the second moulding that, in use, are not required to enter between the walls 6 of the first moulding.

Before the mouldings 1 and 2 are assembled, a ring or other anchorage (not shown) is attached to the second moulding 2. To this end, part of the ring or other anchorage is passed through the gap 11 and moved to the end of the retaining loop 10 further from the recess 13. A barb-shaped formation may be provided, if desired, such as is shown in chain-dotted lines 15 in Figure 4. The ring or other anchorage is snapped past the formation 15 and is prevented by the formation from leaving that end of the retaining loop.

The mouldings are then assembled together. During this process they remain in much the same relative angular orientation as they have in Figures 3 and 4.

The moulding 2 is inserted from below into the slot 6, until the gap 11 lies just beneath the abutment 7. The moulding 2 is then forced upwards, while the spring limb 12 yields resiliently. This continues until the abutment 7 fully enters the retaining loop 10, whereupon the spring limb 12 returns substantially to its original position. One moulding is then shifted lengthwise relatively to the other so that the abutment 7 fits into the recess 13. As this occurs, the tip of the spring limb 12 snaps into an L-shaped recess 16 in the stop 8. This prevents subsequent movement of the abutment 7 from the recess 13.

The assembled shackle is then as shown in Figures 1 and 2. The shackles shown in its closed position, in which the closure 9 closes the mouth 4 of the hook formation 3. If the user squeezes the shackle between his or her thumb and finger, pressing the upstanding portion 14 in the direction of the slot 6, the second moulding 2 rocks about the axis of the abutment 7, thus moving the shackle to its open position, in which the mouth 4 is no longer closed by the closure 9. During this rocking movement relative movement between the stop 8 and the tip of the spring limb 12 causes resilient deflection of the limb. Part of a ring or other component can then be passed through the open mouth 4 into the hook formation. When the user releases the shackle, the force exerted by the spring limb returns the shackle to its closed position.

Whether the shackle is in its open or in its closed position, the walls 6 of the first moulding 1 permanently close the gap 11 so that it is impossible for the ring or other anchorage to leave the retaining loop through the gap even if it is snapped back past the formation 15. The walls thus constitute blocking means.

If, for any reason, it is desired to disassemble the shackle, this can be effected by depressing the limb 12, so that its tip leaves the recess 16, and manipulating the mouldings 1 and 2 so that the abutment can be pulled out of the retaining loop 10 through the gap 11. This is not an easy or obvious manoeuvre but is nevertheless possible. It does enable the shackle to be released from the anchorage to which it was attached. In a modified design of shackle (not illustrated) wedge-shaped abutments are provided on the inner faces of the walls 6, and complementary abutments are provided on the second moulding 2. These abutments are so arranged that during assembly of the shackle the walls 6 are forced resiliently apart and finally snap back again to retain the mouldings is what is effectively permanent engagement.Disassembly could then be effected only by resiliently forcing the walls 6 apart to enable the complementary abutments to pass one another. Such an operation could be effected only with the aid of suitable tools and in any case would be liable to lead to damage or even destruction of the shackle.

It is envisaged that the separate mouldings would be supplied to the manufacturers of harnesses and other gear, and that those manufacturers would attach the shackles to appropriate anchorages on the gear on assembly of the shackles. The gear would then be supplied to the ultimate users on the understanding that they would have no need to remove the shackles from their anchorages, at least in normal use.

When a shackle is in use and its hook formation 3 is attached, for example, to a ring, forces may be exerted that tend to pull the ring towards the mouth 4. Although the mouth is closed by the closure 9, there could be a tendency for the ring to wedge between the hook formation and the closure and displace the closure, thus releasing the ring. To avoid or at least to reduce that possibility, a modification may be adopted in which the end of the closure 9 is shaped that, when the shackle is in its closed position, it presents a concave or recessed abutment face to the interior of the hook formation. Forces urging the ring towards the mouth 4 then cause the ring to engage that abutment face. The shape of a typical concave or recessed abutment face is indicated in Figure 4 by the chain-dotted line 17.

In another modification, a groove, such as that indicated at 18 in Figure 3, is provided in the hook formation 3 adjacent to the mouth 4. The arrangement is such that when the shackle is in its closed position, part of the closure 9 enters the groove. The purpose of this is described above.

iwnerous other modifications are, of course, possible. For example, i: the shackle is to be anchored in some manner that does not require use of the retaining loop 10, the side walls 6 may be extended to overlap the loop to a greater extent or even to conceal it entirely.

It will also be appreciated that the spring means, here exemplified by the limb 12 and associated loop 10, could be provided on the first moulding in place of the side walls 6, while the side walls, together with the abutment 7 and stop 8 is provided on the closure 9.

Such a shackle would still be within the scope of the present invention.

Claims

1. A shackle comprising first and second plastics mouldings which are assembled together and can be rocked relatively to each other, the first moulding having a hook formation with a mouth and the second moulding having an openable closure for the mouth, one of the mouldings also having a portion constituting spring means which, when stressed, applies a force to the other moulding and urges the mauldings towards a closed position, in which the closure closes the mouth of the hook formation, it being possible to rock the mouldings, against the action of the spring means, to an open position, in which the closure no longer closes the mouth of the hook formation.

2. A shackle according to claim 1 in which the spring means forms at least part of a retaining loop with a gap in it, said other moulding having blocking means which permanently closes that gap, the arrangement being such that before the mouldings are assembled the retaining loop can engage a ring or other anchorage, a portion of the ring or other anchorage being passed through said gap into the interior of the loop, but the gap being closed by the blocking means on subsequent assembly of the mouldings.

3. A shackle according to either of claims l and 2 in which it is the second plastics moulding that includes the retaining loop while the first plastics moulding includes the blocking means.

4. A shackle according to either of claims 1 and 2 in which it is the first plastics moulding that includes the retaining loop while the second plastics moulding includes the blocking means.

5. A shackle according to any one of the preceding claims in which the spring means comprises a limb of the retaining loop adjacent to the gap.

6. A shackle according to claim 5 in which one or more barb-like formations are provided between the gap and the other end of the loop further from the gap, the arrangement being such that a portion of a ring or other anchorage that enters the loop through the gap can be snapped past the barb-like formation or formations, to a place at or adjacent to said end of the loop, where it is retained by the formation or formations and is thereby prevented from interfering with the operation of the spring means.

7. A shackle according to any one of the preceding claims in which the mouldings are such that they can be assembled by snap-action.

8. A shackle according to any one of the preceding claims in which mouldings are such that they can also be disassembled by snap-action and can be repeatedly assembled and disassembled at will.

9. A shackle according to any one of claims 1 to 7 in which the mouldings are such that after assembly by snap-action they cannot be disassembled by snap-action.

10. A shackle according to any one of the preceding claims in which the hook formation is formed with a recess or slot opposite the mouth, while the closure is preferably so shaped that it extends into that recess or slot, the closure moving further into the recess or slot when the shackle is moved from its closed to its open position.

11. A shackle according to any one of the preceding claims in which the closure is so shaped that, when the shackle is in its closed position, it presents a concave or recessed abutment face to the interior of the hook formation.

12. A shackle according to any one of the preceding claims in which the hook formation is formed with a groove adjacent to its mouth, part of the closure entering that groove when the shackle is in its closed position.

13. A shackle according to any one of the preceding claims in which one of the mouldings is formed with an abutment which fits into a complementary recess formed in the other moulding, the abutment and recess together constituting a bearing and in use the mouldings rocking about the axis of that bearing, the arrangement being such that during assembly the entry of the abutment into the recess requires resilient deformation of the spring means which finally snaps back to retain the abutment in the recess.

14. A shackle substantially as hereinbefore described with reference to the accompanying drawings.

15. First and second mouldings that can be assembled together to form a shackle in accordance with any one of the preceding claims.