GB2236546A

GB2236546A - Rope termination

Info

Publication number: GB2236546A
Application number: GB9020525A
Authority: GB
Inventors: Derek Kingston
Original assignee: Linear Composites Ltd
Current assignee: Linear Composites Ltd
Priority date: 1989-09-21
Filing date: 1990-09-20
Publication date: 1991-04-10
Anticipated expiration: 2010-09-20
Also published as: GB8921362D0; GB2236546B; GB9020525D0

Abstract

A means for terminating an end of a fibre rope 9 comprises a socket 1, at least part of the inner wall of which is tapered, and a member 3 having the shape of a cone which fits within the socket 1 so as to provide a space between the tapered inner socket and the body of the cone of substantially constant annular area. The fibres 9 are trapped within the constant annular area and are treated with a resin composition which is resilient and/or provides a lubricating effect whereby to improve the resistance to abrasion of the termination. The composition includes waxes, polyester resins, epoxy resins, urethanes, silicones, and synthetic rubbers. <IMAGE>

Description

TERMINATION This invention relates to means for terminating an end of a rope, particularly a rope comprising a row of parallel filaments encased in a sheath of thermoplastic material.

UK Patent No. 1341013 discloses a means for terminating an end of fibre rope comprising a socket at least part of the inner wall of which is tapered, and a member having the shape of a cone with the apex of larger included angle than the body of the cone which fits in the socket, so as to provide a space between the tapered inner socket wall and the body of the cone of substantially constant annular area.

When a rope terminated by such terminal is subjected to extreme conditions of testing there may be, under certain circumstances, a tendency for the fibres in the rope to abrade. For ropes of relatively lower breaking strain, it has been found that abrasion which may occur is mainly in the region where the fibres contact the conical member at the point where the member changes shape to form the apex.

In ropes of relatively heavier breaking strain (eg 400/500 tonnes) abrasion may occur where the fibres contact the inner wall of the socket in the region opposite to that part of the conical member where it changes shape to form the apex.

The invention seeks to reduce or eliminate the above disadvantage.

According to the present invention there is provided a means for terminating an end of a fibre rope comprising a socket, at least part of the inner wall of which is tapered and a member having the shape of a cone which fits within the socket so as to provide a space between the tapered inner socket and the body of the cone of substantially constant annular area, characterised in that the fibres are treated with a resin composition.

The resin composition may be any suitable material which may be applied to the fibres which is resilient and/or provides a lubricating effect. Illustrative examples include waxes, polyester resins, epoxy resins, urethanes, silicones, synthetic rubbers and the like.

The resin composition may be applied to the fibres solely in the areas where abrasion has been known to occur or it may fill the entire termination. The resin composition may be applied before or after the rope is tensioned in order to pull the cone into the socket, preferably the former.

The termination of the invention is particularly but not exclusively suitable for terminating ropes comprising a core of parallel filaments encased in a sheath of thermoplastic material. The term "cone" includes truncated cones and cones in which the wall may be slightly concave or convex in shape.

It is preferred that when the parts are assembled together and ultimately tightened, the area of the annular space between the tapered inner socket wall and the surface of the cone bears a relationship to the total cross-sectional area of the fibres in the rope end. The area may be substantially equal to or just greater than the tota] cross-sectional area of the fibres. It is further preferred that the included cone angle of the body of the cone is less than the natural angle of friction between the material of the cone and the fibres of the rope which is to be terminated.

The term fibre rope as used herein means a rope made of natural or synthetic fibres or mixtures thereof in staple fibre or continuous filament form, and includes both ropes of the conventional twisted structure and ropes comprising a core of substantially parallel continuous filaments, for example polyester filaments, encased in a sheath of thermoplastic polymeric material.

In terminating a rope of twisted structure the rope end is untwisted and the fibres loosened so as to be easily distributed about the inner tapered surface of the socket.

In terminating a rope of the sheathed parallel filament type a section of the sheath at the rope end is first removed. In either case the resin composition may be applied to the fibres before or after inserting into the termination and either before or after making the termination tight.

Depending on the exact resin composition chosen its action is to encase the fibres in a resiliant matrix and protect them from abrasion and/or to provide a degree of lubrication which will also protect them from abrasion.

In any event the abrasion resistance of terminations in accordance with the invention is improved with respect to those described in UK patent 1341013.

The invention will be described further, by way of example, with reference to the accompanying drawing, in which the sole figure is rongitudinal cross-section of a termination in accordance with the invention.

Referring to the drawing, a socket or "barrel" 1 has a generally cylindrical outer configuration and includes an intermediate inner wall 2 of tapered form with an included angle smaller than the included cone angle of the main body of a conical member 3 which fits inside the barrel with a small annular space therebetween. The apex 4 of the member 3 is of larger included angle than the body.

The upper and lower parts of the inner wall of the barrel 1 are of cylindrical form, the diameters of which are respectively equal to the upper and lower diameters of the tapered part 2. A pair of diametrically opposed apertures 6 may be formed in the socket 1 for attachment of a pin or shackle or other mounting means as is known in the art.

Similarly, a small plug 7 may be inserted into the upper cylindrical portion of the socket 1 ,o close off the fibre cone after the termination process has been completed.

The rope illustrated in the drawing comprises a core of parallel filaments 9 encased in a thermoplastic sheath 8.

A length of the sheath approximately equal to the length of the main body portion of the member 3 is removed from the rope end and the latter inserted into the lower portion of the barrel 1. In the conventional termination the apex 4 of the conical member 3 is then inserted into the centre of the fibre mass and driven down until tightly wedged, at which point the tapered apex 4 should have penetrated into the sheathed portion of the rope 8.

Alternatively, the cone 3 may be drawn down until it is wedged in the tapered portion 2 by tensioning the rope.

In accordance with the present invention the fibres are treated with a resin composition, for example a polyester resin, preferably before the cone 3 is inserted into the loose fibre ends 9. The resin composition should be placed in such that it ends up the zone 10 so that it holds the fibres 9 in the area of the apex of the cone and at the point where the angle of the cone changes. If desired, however, the whole of the loose fibre ends 9 may be treated with the composition.

It has been found that the means of terminating in accordance with the invention provides a termination with improved abrasion characteristics over those of UK patent 1341013 and the results from accelerated testing proceedures show a marked improvement.

Claims

1. A means for terminating an end of a fibre rope comprising a socket, at least part of the inner wall of which is tapered, and a member having the shape of a cone which fits within the socket so as to provide a space between the tapered inner socket and the body of the cone of substantially constant annular area, characterised in that the fibres are treated with a resin composition.

2. A means as claimed in claim 1 wherein the resin composition is resilient and/or provides a lubricating effect.

3. A means as claimed in claim 2 wherein the resin composition includes waxes, polyester resins, epoxy resins, urethanes, silicones and synthetic rubbers.

4. A means as claimed in any of claims 1 to 3 in which the area of the annular space between the tapered inner socket wall and the surface of the cone, when the parts are assembled together and ultimately tightened, is equal to or just greater than the total cross sectional area of the fibres in the rope end.

5. A means as claimed in any of claims 1 to 4 wherein the included cone angle of the body of the cone is less than the natural angle of frictin between the material of the cone and the fibres of the rope which is to be terminated.

6. A means as claimed in any of claims 1 to 5 wherein the rope is made of natural or synthetic fibres or mixtures thereof in staple fibre or continuous filament form and is of conventional twisted structure or comprises a core of substantially parallel continuous filaments encased in a sheath of thermoplastic polymeric material.