GB2261468A

GB2261468A - Releasable locking hook

Info

Publication number: GB2261468A
Application number: GB9223972A
Authority: GB
Inventors: John Wigmore
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-16
Filing date: 1992-11-16
Publication date: 1993-05-19
Also published as: GB9124416D0; GB9223972D0

Abstract

A releasable locking hook has a hasp assembly 20 carried on a mount 10 such that under load, the hasp assembly is moved downward relative to the mount against a spring loading (14, 15). The hasp assembly consists of a hasp 40 pivoted on a hasp base 30, the hasp engaging with a control mechanism (60, 70), downward movement of the hasp base locking the control mechanism into position against a stop means 80 to maintain such engagement, emergency release stop means 80 allowing the control mechanism to be released even under load. The control mechanism includes a first pivoted element (the cam or lever 70) abutting against the emergency release stop 80, carried on the mount 10, when the hasp assembly 20 is moved downward by a load, and a second pivoted element (the cam or lever 60) intermediate between and engaging with both the first pivoted element 70 and the hasp 40. The stop is withdrawable to release the hook even under load. <IMAGE>

Description

Releasable Locking Hook The present invention relstes to releasable locking hooks.

A locking hook is e hook which is intended for lifting substantial weights, and which locks into position, when under loed, so that there is no danger of the load being released from the hook. A releasable locking hook is a locking hook with emergency release means which can be operated to unlock the hook and so release the load even when the hook is loaded.

A releasable locking hook is known from GB 2 193 526 A. In that hook, a hasp Assembly is carried on a mount sllch that under lond, the hasp assembly is moved downward relative to the mount against a spring loading. The hasp assembly consists of a hasp pivoted on e hasp bese. The hasp engages with 8 control mechanism, and the downward movement of the hasp bese locks the control mechanism into position to maintain such engagement. An emergency release means allows the control mechanism to be released even under load.

In the mechanism of GB 2 193 i2fi A, the control mechanism consists essen- tiaJly of e pivoted lever carried on the hasp assembly, one end of the lever engaging with the free end of the arm of the hasp. The other end of this lever abuts against a stop, carried on the mount, when the hasp assembly is moved downward by e load. The stop is withdrawable to release the hook even when it is loaded.

The object of the present invention is to provide an improved form of releasable locking hook of the type having 8 hasp assembly carried on a mount such that under load, the hasp assembly is moved downwerd relative to the mount against a spring losding, the hasp assembly consisting of a hasp pivoted on a hasp base, the hasp engaging with a control mechanism, the downward movement of the hasp bese locking the control mechanism into position to maintain such engagement, and an emerg'ency release means allowing the control mechanism to be released even under load.

Accordingly the present invention provides a releasable locking hook in which the control mechanism includes e first pivoted element (a cam or lever) straining the motion of the hasp base can be employed, eg a pin in the hasp base (or mount) sliding in a vertical slot in the mount (or hespz base), or the mechanism shown in GB 2 193 526 A mentioned above. Also, the hasp base may, like the mount, consist of two plates with the hasp 40 lying between them.) The hasp base 30 is urged upward relative to the mount 10 by a spring 14, which is located in e vertical slot 32 in the hasp base.The upper end of this spring, which is in compression, bears against the top end of the slot, and its lower end bears against a stop 15 forming part of the mount 10 and projecting out from the main body thereof through the slot 32. (Again, any convenient equivalent mechanism can be used.) The control mechanism consists of en intermediate cam or lever 60 pivoted on 8 pivot 61, a final cam or lever 70 pivoted on a pivot 71, and an emergency release peg 80.The cam 60 is urged into the position shown by spring means shown as a tension spring 62 stretched between a point on the cam 60 and a point on the mount 10, and the cam 70 is urged anticlockwise into the position shown by spring means shown as a tension spring 72 stretched between a point on the cam 70 and a point on the mount 10. (Again, any convenient form of spring means can be used for either or both of these spring means, eg 8 spring coiled around the appropriate pivot.) The cam 70 has a release arm 73 extending away from the pivot as shown. (In practice, the arm 73 may be located on the outside of one of the pletes of the mount 10, and attached to the rest of the cam 70 via the pivot shaft 71.) Fig. 1 shows the hook in the unloaded position but with the hasp 40 in the latched position.To attach or release a load on the hasp, the hasp must be rotated anticlockwise to lower the end of the release arm 41 below the bottom edge of the corner 12 of the mount 10.

With the components of the control mechanism 50 in the positions shown, the hasp is prevented from such rotation by the right-hand end 63 of the cam 60, which engages with an extension 42 of the hasp which extends beyond (ie on the opposite side of) the pivot 31 to the end 42. The cam 60 is in turn prevented from rotating clockwise (and thereby releasing the hasp 40) by the lower left-hand end 74 of the cam 70, which engages with the upper left-hand projection 64 of the cam 60.

The hasp is thus locked In position; that is, the hook is locked, and cannot be released by the release arm 73. The load is thus held safely, end its rope or cable cannot become accidentally released. When the load is taken off the hook, however, the components of the hook return to the position shown in Fig.

1, end turning the release arm 73 downward allows the rope or cable of the load to be easily disengaged from the hasp 40. If, however, it is necessary to release the load while it is being supported by the hook, this can be achieved by removing the emergency release peg 80.

Figs. 3 and 4 show various alternative forms of the emergency release peg 80. The function which this peg has to perform is to remain securely in position in normal use, with no danger of it coming out accidentally, but to be reedily removable when desired. It is convenient to use some form of springloaded peg with a twist catching action (8 bayonet-type action) for this.

Fig. 3A shows in side view a peg 80 consisting of a rod 81 having a handle 82 and a pair of pins 83 projecting from it (best seen in the end view of Fig.

3135. The hasp base 30 has projecting from its main body a stub tube 33 with e captive spring 34 held in it end fl pair of J-shaped slots 35. The end of the peg 80 can be pushed into the tube 33 against the spring 34 and twisted so that the pins 83 enter the slots 35 and pass along and round them to the ends of their short inner arms. The peg is then held safely in position, but can readily be released by pushing it inward and turning it to bring the pins into the long arms of the .T-shaped slots.

Fig. 4A shows in side view 8 modified form of peg 80' consisting of a rod 81' having a handle 82' and a locking plate 83' in the form of a disc with two cutouts 84 (best seen in the end view of Fig. 4B). The hasp base 30 has projecting from its main body a stub tube 33' with a captive spring 34' held in it and an end cap 36 with a circular hale having a pair of inwardly pointing ears 37 (best seen in the end view of Fig. 4C). The end of the peg 80' can be pushed into the tube 33' against the spring 34' with the ears 37 aligned with the cutouts 84 and then twisted to bring the cutouts clear of the ears. The peg is then held safely in position, but can readily be released by pushing it slightly inward and turning it to bring the ears and cutouts into alignment again.

Fig. 5 shows a modification of the hook of Figs. 1 and 2. The locking pin 80 is replaced by a locking arm 100, pivoted on the mount 30 at a pivot 101. A locking fork 90 with two arms 92 and 93 is pivoted on a pivot shaft 91 mounted in the casing 10. The mount 30 has no slot at its upper left-hand end, and is cut back at that end as shown to allow clearance for the locking lever 90 and locking arm 100.

When the hook is unloaded and the mount 30' is in its upper position, the arm .100 can pivot freely. The clearance between the lower end 102 of the arm 100 and the surface 75 of the cam 70 allows that cam to be rotated, so allowing cam 60 to rotate and hence freeing the hasp 30 for release.

When the hook is loaded and the mount 30 is lowered, the lower end 102 of the locking arm 100 engages in the fork 90 between the arms 92 and 93. Its lower end 102 is therefore held in position against the surface 75 of the cam 70, which is therefore held in position against rotation, so locking the hook.

The pivot shaft 91 is rigidly attached to the locking fork 90, and projects through a hole (not shown) in the casing 10 of the hook, and carries a lever (not shown) mounted outside The casing. By turning this lever, the locking fork can be forced to rotate anticlockwise. This forces the lower end 102 of the arm 100 to the left, out of engagement with the surface 75 of the cam 70.

Cam 70 is thus released, and can be rotated by means of the arm 73, so releasing the cam 60 end hence the hasp of the hook.

It will be seen from the above description that the present arrangement is concerned with a releasable locking hook of the type having a hasp sssembly 20 carried on a mount 10 such that under load, the hasp assembly is moved downward relative to the mount against a spring loading (14, 15), the hasp assembly consisting of 8 hasp 40 pivoted on a hasp base 30, the hasp engaging with a control mechanism (60, 70), the downward movernent of the hasp base locking the control mechanism into position to maintain such engagement, and sn emergency release means 80 Allowing the control mechanism to be released even under load.

The present arrangement provides a releasable locking hook in which the control mechanism includes a first pivoted element (the cam or lever 60) enter mediate between and engaging with the hasp 40; stop means (the emergency release peg 80) carried on the mount 30; and a second pivoted element (the cam or lever 70) engaging with the first pivoted element, when the hasp assembly is moved downwerd by a load to hold the hook against release, and the' stop means; the stop being withdrawable to allow the release of the hook even when loaded.

The present arrangement also provides a releasable locking hook in which the control mechanism consists of lever means (60, 70) mounted on the hasp base and a stop C80, mounted on the mount.

The present arrangement also provides a releasable locking hook in which the hasp 40 has an extension 42 beyond (ie on the opposite side of) its pivot 31 to its main arm 41, with which the control mechanism engages.

The present arrangement also provides a releasable locking hook in which the control mechanism includes a pivoted element (the cam or lever 60) which engages with the hasp 40 and moves one way (clockwise) from a reference position (full lines in Figs. 1 and 2) to allow the hasp to open, and is moved the other way (anticlockwise) from the reference position by the return of the hasp to its closed position, as the projection 42 pushes the right-hand end of the cam 60 upward.

Claims

1 A releasable locking hook in which the control mechanism Includes a first pivoted element (a cam or lever) intermediate between and engaging with the hasp; stop. means carried on the mount; and a second pivoted element (a cam or lever) engaging with the first pivoted element, when the hasp assembly is moved down wsrd by a load to hold the hook against release, and the stop means; the stop being withdrawable to allow the release of the hook even when loaded.

2 A releasable locking hook according to claim 1 wherein the hasp has an extension beyond Cie on the opposite side of) its pivot with which the control mechanism engages.

3 A releasable locking hook according to either previous claim in which the second pivoted element moves one way from a reference position to allow the hasp to open, and is moved the other way from the reference position by the return of the hasp to its closed position.

4 A releasable locking hook according to any previous claim wherein the stop means is withdrawable perpendicularly to the plene of the second pivoted element.

5 A releasable loclcing hook sccording to claim 4 wherein the stop has a beyonet engagement with the mount.

6 A releesable locking hook according to claim 4 wherein the stop includes a disc with a pair of diametrically opposite cut-outs and the mount has a circular aperture with a pair of diametrically opposite inwardly projecting ears such that the disc of the stop can enter through the aperture and will engage with the ears on being given 8 quarter turn.

7 A releasable locking hook according to any previous claim wherein the stop means is withdrewohle parallel to that surface of the second pivoted element with which it engages.

8 A releasable locking hook according to claim 7 wherein the stop means cornprise an arm pivoted on the mount.

9 A releasable locking hoole according to claim 8 wherein the stop means engage with 8 fork arm rotatable to withdrew the stop means.

10 A releesable locking hook substantially as herein described and illustrsted.

11 Any novel and inventive feature or combination of features specifically disclosed herein within the meaning of Article 4H- of the International Conven Lion (Paris Convention).