GB2326668A

GB2326668A - Restraints for elongate members

Info

Publication number: GB2326668A
Application number: GB9813681A
Authority: GB
Inventors: Ronald Potter
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-06-25
Filing date: 1998-06-25
Publication date: 1998-12-30
Also published as: GB9813681D0

Description

"A Restraint Device" The invention relates to a restraint device for restraining two sections of elongate member, and particularly, but not exclusively, relates to a restraint device for restraining a sling formed from a rope.

Conventionally, slings formed from ropes are used to carry a load such as a collection of pipes. The sling is formed by firstly forming a noose at each end of the rope, and then passing one end of the rope through the noose in the other end of the rope. The load to be carried is then placed into the adjustable loop created by the sling, and the opposite end of the rope from the noose end is lifted, thereby pulling the rope through the opening of the noose until the sling tightly grips the load.

However, when the load is lowered and subsequently makes contact with the ground, the sling will slacken off as it is no longer under load. This slackening off of the sling firstly may be inconvenient if the load is to be lifted again, and secondly may be dangerous, as it may slacken off in a violent manner.

Conventionally, it is known to attempt to prevent the slackening of the sling by attaching a restraint device, known as a "bulldog grip" to the rope just above the location where the sling has formed on the rope, and when the sling is under load. The bulldog grip comprises a rectangular block, with a groove formed along one face. Apertures extend through the block on either side of the groove. The block is applied to the rope with the rope locating in the groove just above the location of the sling when the sling is on load. The two screw threaded ends of a ushaped rod are then passed through the apertures so that the rope is trapped in the groove by the u-shaped rod. Nuts are screwed onto the rod ends and used to tighten together the u-shaped rod and the block, thereby locking the block and u-shaped rod to the rope.

According to the present invention, there is provided a restraint device for restraining two sections of elongate member, the restraint device comprising a body member for engagement with a first section of elongate member, and a restraint surface for engagement with at least a portion of the outer surface of a second section of elongate member.

Further according to the present invention there is provided a restraint device for rope or the like, the device having a body member for receiving the rope and a wedge member adapted to wedge the rope in the body member.

The engagement of the body member on the first section, and of the restraint surface against the second section, resists relative movement of the first and second sections.

The wedge member (and/or the body member) may incorporate means to prevent relative movement of the rope and body member.

The means to prevent relative movement can comprise a ratchet between the wedge member and the body member.

The wedge member may also have studs to prevent relative slippage of the wedge member and the rope.

The studs may be adapted to engage grooves present on the rope, eg, in the grooves formed between strands of the rope.

Preferably, the body member is selectively locked to the first section by a locking mechanism.

The body member may be tubular, whereby the first section of elongate member is located within the bore of the body member, and a locking mechanism may be inserted between the first section of the elongate member and a wall of the body member. The said mechanism may be a wedge member.

Alternatively, the body member may comprise a hinge and two side by side members adapted to close about the hinge, and around the first portion of the elongate member.

Preferably, the first and second sections of elongate member form part of the same elongate member.

Preferably, the restraint surface is mounted on the body member. Typically, the restraint surface is formed by a recess, protrusion, shoulder, hook, catch or the like.

Preferably, the restraint surface is shaped to substantially correspond to at least a portion of the second section of elongate member.

Preferably, the elongate member is cylindrical, and more preferably, the restraint surface is substantially semi-circular.

Typically, the studs are spaced diagonally from one another.

The studs may be spaced apart so as to engage in the same groove of the rope, or alternatively, the studs may engage in spaced apart grooves of the rope.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a rope forming a sling to which a restraint device of Fig. 2 can be attached; Fig. 2 is a perspective view of a first embodiment of restraint device in accordance with the present invention; Fig. 3 is a cross-sectional view of the restraint device of Fig. 2; Fig. 4 is a front view of a wedge for use with the restraint device of Fig. 2; Fig. 5 is a side view of the wedge of Fig. 4; Fig. 6 is a perspective view of a second embodiment of a restraint device in accordance with the present invention; Fig 7 shows perspective views of a second embodiment of a wedge; Figs 8 and 9 show a perspective view of a third restraint device of the invention; Fig 10 shows cutaway views (a and c) of the Fig 8 device in use; Figs 11 and 12 show the wedge and ratchet arrangement of the Fig 8 device; Fig 13 shows the body of the Fig 8 device; and Fig 14 shows the wedge of the Fig 8 device in detail.

Fig. 1 shows a conventional rope 1 with which a restraint device 10, 30 of the present invention can be used. The rope 1 has a noose 3, 4 at both extremities, where the nooses 3, 4 are typically formed by forming a loop at each end of the rope 1 and crimping. In Fig. 1 the upper noose 3 will be used for attachment to a hook (not shown) to enable the rope 1 to be lifted. The upper noose 3 is passed through the opening 5 of the lower noose 4 to create a sling 6. Thereafter, a load (not shown), for instance a collection of pipes can be carried within the loop 7 of the sling 6 when the upper noose 3 is lifted by a lifting device (not shown) such as a crane.

A restraint device 10 in accordance with the present invention is shown in Fig. 2 as comprising a body member 12 and two side arms 14 which are spaced apart and parallel with respect to each other, and which are welded to, and project outwardly, from the body member 12.

The lowermost end of each side arm 14 is formed with a semi-circular cut-out 15, the semi-circular cut-out 15 having a radius approximate to that of the rope 1 with which the restraint device 10 is intended to be used.

The body member 12 consists of a hollow tube 16, 18, with a bore 13 which is ovoid in cross-section, the portion 16 being wider than the portion 18. The portion 16 tapers linearly inwardly along the length of the body member 12 from its intended, in use, upper end 17 (as shown in Fig. 2) to its lower end 19. Located on the inner bore of the portion 16 is a downwardly facing ratchet mechanism 20, which can be seen more clearly in Fig. 3, where the body member 12 is shown without the side arms 14.

A tapered wedge 22 is shown in Figs. 4 and 5 as having a leg 23. On one face of the leg 23, and at the (in use) upper end, there is an outwardly projecting shoulder 26, and on the same face of the leg 23, is an upwardly facing ratchet mechanism 24 which extends along the said face of the leg 23.

In use, the restraint device 10 is attached to the rope 1, by threading one end of the rope 1 through the bore 13 of the body member 12, such that when the two nooses 3, 4 are created on the rope 1, the restraint device 10 is slidable along the rope 1 between the two nooses 3, 4. Thereafter, when the sling 6 is formed and a load is lifted, the restraint device 10 will slide down the rope under its weight and come to rest upon the uppermost part of the sling 6.

The restraint device 10 is rotated so that the semicircular cut-out 15 of each side arm 14 is located over the uppermost portion of the lower noose 4. The wedge 22 is then inserted into the bore between the ratchet mechanism 20 and the rope 1, with the shoulder 26 projecting outwardly from the restraint device 10. The wedge 22 can then be hammered downwardly as far as is possible, and thus the downwardly facing 20 and the upwardly facing 24 ratchet mechanisms co-operate to prevent the wedge 22 from accidental ejection from the bore 13. The rope 1 is then trapped between the wedge 22 and the wall of the portion 18 of the body member 12.

Thereafter, when the rope 1 is lowered to the ground, the sling 6 will be prevented from opening by the restraint device 10, as the restraint device 10 is securely locked to the rope 1. When the load is required to be released from the sling 6, the wedge 22 is removed from the bore 13 by hammering upwardly against the underside of the shoulder 26, thereby overcoming the co-operation of the ratchet mechanisms 20, 24, and ejecting the wedge 22 from the bore 13.

Fig. 6 shows a second embodiment of a restraint device 30 where the restraint device 30 comprises a u-shaped body member 32, with parallel side arms 14 again projecting outwardly from the u-shaped body member 32.

Both side arms 14 have a threaded hole 36; and a semicircular cut-out 15 on their lowest edges, as in the first restraint device 10.

The restraint device 30 is slipped around the rope 1 when the rope 1 is on load, such that the semi-circular cut-outs 15 locate over the uppermost portion of the lower noose 4. A threaded bolt (not shown) is then passed through the two threaded holes 36 in the side arms 14, and tightened by nuts (not shown) to bring the side arms 14 together, thus closing the side arms 14 around the rope 1, thereby locking the restraint device 30 to the rope 1. The u-shaped body member 32 thus acts as a hinge about which the two side arms 15 pivot.

The restraint device 30 thus restrains the sling 6 in a manner similar to the first restraint device 10 described previously. When the sling 6 is required to release the load, the bolt is loosened and the side arms 14 are pulled apart, thereby loosening the grip of the body member 32 around the rope 1.

The intended dimensions of the first restraint device 10 are as follows. The width of the restraint device 10 from the outermost portion of the said portion 16 to the furthest edge of the side arms 14 is between two and three inches. The height of the restraint device 10 is between one and two inches, and the depth of the steps of the upwardly 24 and downwardly 20 facing ratchet mechanisms 20 is 0.032 inches. The dimensions of the second restraint device 30 are similar to that of the first restraint device 10, that is a width of between two to three inches, and a height of between one to two inches.

Conventionally, the rope 1 is wire rope, and is typically 3/, of an inch in diameter. The first and second restraint devices 10, 30 will typically have 1/16 of an inch or 1/8 of an inch thick side walls, and the wedge typically tapers from 1/4 of an inch at its widest end, to zero inch.

A third embodiment of the invention incorporating an improvement is shown in Figs 7-14. The third embodiment 100 has many features in common with the first embodiment described herein, and has been annotated with reference numerals showing the corresponding features but with an extra 0 added to the end of the reference numerals of the third embodiment.

The third embodiment differs from the first in that the wedge 220 has one face 220a which is convex to cooperate with the inner bore of the body 120 and incorporates a ratchet arrangement 240 composed of 75 900 steps. The ratchet steps are linear and extend between two side walls 240w defining the edges of the ratchet arrangement 240 so that it does not extend around the whole of the convex surface 220a. The opposite face 220b is concave to cooperate with the rope 6 and is provided with studs 225 which protrude from the surface 220b and are spaced diagonally from one another.

When the rope 6 is in place in the tube 160/180 and the wedge 220 is driven into the body 120 at 160, the surface 220b of the wedge 220 is forced against the rope 6, and the hook 145 formed by the lower portions of the arms 140 engages the rope 6. The wedge 220 is prevented from rotating in the tube 160 by the side walls 240w of the ratchet arrangement 240 engaging the ratchet steps, and is prevented from sliding upwards by the ratchet 240 itself.

The studs 225 engage in grooves which extend in a helix around the rope between the rope strands 6s as shown in Fig 12, and further downward movement of the wedge 220 forces the studs 225 further into the grooves. The studs 225 can be placed to engage in the same or spaced-apart grooves on the rope 6.

As the wedge 220 moves down the tube 160, the studs 225 are driven further into the grooves and lock the rope 6 against upward sliding movement in the tube 180 since the top of each of the studs 225 abuts against the uppermost strand 65 in the groove. Upward force on the rope 6 may drive the studs 225 deeper into the groove(s) but the studs 225 will not be able to skip a strand 65 to the next groove and sliding of the rope 6 in the tube 180 will thus be prevented. Thus when the tension on the rope 6 is released the device 100 remains in place, resisting sliding movement of the rope 6.

An additional benefit is provided in that the studs 225 also prevent rotation of the rope 6 in the tube 180.

The action of the studs 225 between the strands of rope 6s may unravel the rope 6 to some extent, but this may actually prevent slippage still further.

The wedge 220 is coupled to the device 100 by a string 255, and can be removed from the tube 160 by hammering upwardly against the underside of the shoulder 260.

It is possible that the wedges 22; 220 could be formed from a softer material than the body 12; 120, since this would provide the advantage that the wedge could be sacrificed due to a wearing of the ratchet mechanism 24; 240 thereon, to the benefit of the ratchet mechanism 20; 200 of the body 12; 120.

Modifications and improvements may be made to the embodiments without departing from the scope of the invention.

Claims

CLAIMS:

1. A restraint device for restraining two sections of elongate member, the restraint device comprising a body member for engagement with a first section of elongate member, and a restraint surface for engagement with at least a portion of the outer surface of a second section of elongate member.

2. A restraint device according to claim 1, where the body member is locked to the first section by a locking mechanism.

3. A restraint device according to either of claims 1 or 2, wherein the body member is a tubular, whereby the first section of elongate member is located within the bore of the body member.

4. A restraint device according to claim 2, or to claim 3 when dependent on claim 2, wherein the locking mechanism includes a locking device which is inserted between the first section of elongate member and a wall of the body member.

5. A restraint device according to claim 4, wherein the locking device is a wedge member.

6. A restraint device according to either of claims 1 or 2, wherein the body member comprises a hinge and two side by side members adapted to close about the hinge, and around the first section of elongate member.

7. A restraint device according to any of the preceding claims, wherein the first and second sections of elongate member are sections of the same elongate member.

8. A restraint device according to any of the preceding claims, wherein the elongate member is cylindrical.

9. A restraint device according to any of the preceding claims, wherein the restraint surface is located on the body member.

10. A restraint device according to any of the preceding claims, wherein the restraint surface is formed by a recess or a hook.

11. A restraint device according to any of the preceding claims, wherein the restraint surface is shaped to substantially correspond to at least a portion of the second section of elongate member.

12. A restraint device according to any of the preceding claims, wherein the restraint surface is substantially semi-circular.

13. A restraint device according to claim 5, or to any of claims 7 to 12 when dependent on claim 5, wherein the wedge member incorporates means to prevent relative movement of the first section of the elongate member and the body member.

14. A restraint device according to claim 13, wherein the means to prevent relative movement comprise a ratchet between the wedge member and the body member.

15. A restraint device according to claim 5, or to any of claims 7 to 14 when dependent on claim 5, wherein the restraint device includes studs to prevent relative slippage of the wedge member or the body member, and the first section of elongate member.

16. A restraint device according to claim 15, wherein the studs are adapted to engage grooves present on the first section of elongate member.

17. A restraint device for rope or the like, the device having a body member for receiving the rope and a wedge member adapted to wedge the rope in the body member.

18. A restraint device according to claim 17, wherein the wedge member incorporates means to prevent relative movement of the rope and body member.

19. A restraint device according to claim 18, wherein the means to prevent relative movement comprises a ratchet between the wedge member and the body member.

20. A restraint device according to any of claims 17 to 19, wherein the restraint device includes studs to prevent relative slippage of the wedge member or the body and the rope.

21. A restraint device according to claim 20, wherein the studs are adapted to engage grooves present on the rope.

22. A restraint device according to any of claims 17 to 21, wherein the body member is a tubular, whereby the rope is located within the bore of the body member, and the wedge member is inserted between the rope and a wall of the body member.

23. A restraint device according to any of claims 17 to 22, further comprising a restraint surface for restraining a second section of rope.

24. A restraint device according to claim 23, wherein the restraint surface substantially corresponds to at least a portion of the outer surface of the second section of rope.

25. A restraint device according to either of claims 23 or 24, wherein the restraint surface is shaped to substantially correspond to at least a portion of the second section of rope.

26. A restraint device according to either of claims 20 or 21, wherein the studs are spaced diagonally from one another.

27. A restraint device according to any of claims 20, 21 or 26, wherein the studs are spaced apart so as to engage in the same groove of the rope.

28. A restraint device according to any of claims 20, 21, 26 or 27, wherein the studs are spaced apart so as to engage in spaced apart grooves of the rope.

29. A restraint device substantially as hereinbefore described with reference to the accompanying Figs.