GB2180585A - Rope fastening - Google Patents

Abstract

A device for securing a rope which in use is subject to a tensile load, comprises means defining an elongate passageway (1) through which the rope can freely extend and clamping means (7) disposed alongside the passageway (1) for clamping a portion of the rope that in use extends out from one end of the passageway (1). <IMAGE>

Description

SPECIFICATION A device for securing a rope The present invention relates to a device for securing a rope particularly a wire rope which in use is subject to a tensile load and more particularly relates to a device which enables quick replacement and re-reeving of wire ropes on for example cranes, excavators and winches.

It is known to secure a wire rope by means of a wedge and socket arrangement in which an end portion of the rope passes around a pear shaped wedge located within the socket.

The socket can be attached to a hook block of a crane and when the length of wire rope that has not been passed around the wedge is put under tension by the hook block being used to lift a load the wedge is forced into the socket and the wire rope is squeezed between the wedge and the socket. This squeezing action prevents the rope slipping between the wedge and the socket. Also that length of wire rope which extends out of the wedge and socket arrangement after being passed around the wedge is not subject to tension. In some cases this length, known as the "dead end" is turned into a loop and the two ends of the loop clamped together, the loop being lightly secured to that length of the wire rope not passed around the wedge known as the "live end".A disadvantage of this arrangement is that the looping of the "dead end" of a wire rope requires a relatively large radius which reduces the headroom available when lifting a load. Also when relatively large wire ropes are used problems can arise with the mechanical strength of the binding which secures the loop to the live part of the rope.

It has also been proposed to clamp a short length of wire rope to the "dead end" of the main wire rope. However, this can easily become lost on site when rigging or de-rigging and can twist out of line and interfere with obstructions.

A disadvantage of both these devices is that the wedge can become displaced from the socket on impact or if a hook block or lifted load is placed down.

A device for securing a rope which in use is subject to a tensile load, comprising means defining an elongate passageway through which the rope can freely extend and clamping means disposed alongside the passageway for clamping a portion of the rope that in use extends through one end of the passageway.

The means defining the passageway may comprise a tube of circular cross-section.

The tube may be hinged longitudinally to allow the rope to be inserted in the tube.

The clamping means may comprise a first member connected to the tube by a web, a second member facing the first member, each member being provided with an elongate recess preferably having gripping "dimples" facing the recess in the other member so that the rope can be received therebetween, and tightening means to clamp and grip the rope between the recesses.

The present invention will be more particularly described by way of example and with reference to the accompanying drawing in which: Figure 1 shows a perspective view of a device according to the present invention for securing a wire rope which in use is subject to a tensile load, and Figure 2 shows the device illustrated in Fig.

1 in combination with a wedge and socket terminal fitting for a crane hook, block or alternative anchorage point.

Referring to Figs. 1 and 2, the device comprises an elongate metal tube 1 of circular cross-section and length approximately equal to ten times its diameter. The tube 1 is connected by means of a metal web 3 to a metal plate 4 provided with an elongate concave recess 5 extending along its entire length.

Mounted to the plate 4 by means of nuts and bolts 6 is a generally I-shaped metal member 7. The I-shaped member 7 is provided with an elongate recess 8 extending along its entire length with gripping dimples and facing the recess 5 in the member 4. The wire rope 2 extends (as shown in Fig. 2) downwardly into the tube 1 from for example the jib of a crane (not shown) and the internal diameter of the tube 1 is such as to permit free sliding movement of the wire rope 2 within the tube 1.

The lower end portion of the wire rope 2 which extends from the bottom of the tube 1 passes into a socket 9 and round a wedge 10 located within the socket 9. The lower end portion of the wire rope 2 extends upwardly from the wedge and socket terminal fitting between the two members 4 and 5 and opposite sides of the lower end portion of the wire rope 2 are received in the recesses 5 and 8 where it is clamped in position between the members 4 and 7 by tightening the nuts and bolts 6.

In an alternative arrangement (not shown) the tube 1 is hinged longitudinally so that it can be opened to allow the rope 2 to be located within the tube 1 without feeding the wire rope 2 lengthwise through the tube 1.

On exerting a tensile load on the wire rope 2 when a load is lifted by a hook attached to the wedge and socket terminal fitting the wedge 10 is forced upwardly within the socket 9 thereby squeezing the wire rope 2 on each side of the wedge 10 against the inner walls of the socket 9. The higher the tensile load on the wire rope the greater would be the squeezing action of the wedge and the socket 9 against the wire rope 2 and thereby the greater the resistance to slipping of the wire rope 2 through the wedge and socket terminal fitting.

If the hook is lowered to such an extent that it rests on the ground and no tensile load is exerted on the rope 2 the rope 2 will become slack and the wedging effect greatly reduced. As can be seen from Fig. 2 the bottom of the tube 1 is only a small distance from the top of the wedge and socket terminal fitting and therefore the wire rope 2 can only pass into the wedge and socket end fitting by a correspondingly small distance if the wedge 10 should become loose within the socket 9. There is no danger of the wire rope 2 slipping out of the fitment because it is clamped between the plates 4 and 7. Furthermore, since the wire rope 2 can only pass a small distance into the fitment there is no danger of the wedge 10 falling completely out of the socket 9.

Since the tensile load exerted on the wire rope 2 during operation is taken by the terminal fitment the lower end portion of the wire rope 2 which extends upwardly between the plates 4 and 7 is not subject to tensile loading. This enables that portion of the rope 2 to be clamped with a relatively low force.

If instead of using the device according to the present invention the wire rope 2 was secured only by the wedging action of the wedge 10 and socket 9 there would be a danger that if the hook block rested on the ground the wedging action would cease and the wire rope 2 could be pulled out of the terminal fitting. If the lower end of the wire rope 2 were looped after passing upwardly from the terminal fitting and the loop attached to the other part of the wire rope 2 extending downwardly into the terminal fitting a reduction of useful headroom would occur as a re sult of the relatively large loop that has to be made in wire rope due to its stiffness. Furthermore if a separate short length of wire rope were clamped to the lower end portion of the wire rope 2 this short length could easily be lost.

Further security can be extended in the "non return" of the wire rope, by utilising a heavy duty rope clamp 11 retained to the main body by a chain 12.

Claims (6)

1. A device for securing a rope which in use is subject to a tensile load, comprising means defining an elongate passageway through which the rope can freely extend and clamping means disposed alongside the passageway for clamping a portion of the rope that in use extends out from one end of the passageway.

2. A device as claimed in claim 1, wherein the means defining the passageway comprises a tube of circular cross-section.

3. A device as claimed in claim 2, wherein the tube is hinged longitudinally to allow the rope to be inserted in the tube.

4. A device as claimed in any one of the preceding claims, wherein the clamping means comprises a first member connected to the tube by a web, a second member facing the first member, each member being provided with an elongate recess.

5. A device as claimed in claim 4, wherein the recess comprises gripping dimples facing the recess in the other member so that the rope can be received therebetween, and tightening means to clamp and grip the rope between the recesses.

6. A device for securing a rope substantially as hereinbefore described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.