Process for fabricating a dead end of the spelter socket type for wire cables

[57] ABSTRACT

A collar having a plurality of wire strands is attached to a spelter socket after the latter is poured around a splayed end of a wire cable. The wires are braided around the wire cable to enhance the cable’s fatigue life.

Claims, 3 Drawing Figures

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PATENTED *λϊ 30197?

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3,665,587

PROCESS FOR FABRICATING A DEAD END OF THE SPELTER SOCKET TYPE FOR WIRE CABLES

CROSS REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 781,570, filed Dec. 5, 1968, now U.S. Pat. No. 3,568,265, issued Mar. 9, 1971.

BACKGROUND OF THE INVENTION

The present invention relates to the art of wire cables and, in particular, to an improvement in dead ends of the spelter socket type and a process for fabricating the improvement.

It has long been recognized that there is a problem of wire rope or cable failure at terminal fittings or points of rigid support. Failure is due to high stress concentrations at these points. Stress concentrations are in turn due to radical changes in mass and section moduli between the wire rope and its fitting or point of rigid attachment. Failure is normally manifested by a combination of bending and torsional fatigue stresses and often accelerated by the effects of corrosion.

It has been recognized previously that failure at terminal fittings or points of rigid support of wire cable may be alleviated by a reinforcement provided by wire strands wound tightly about a length of the cable from the terminal fitting or point of rigid support.

In general, the prior art has applied reinforcement with wires integrally connected to a terminal fitting or, independently of a terminal fitting, by hand-wound wire alone applied to the cable.

However, there is one type of dead end for which these techniques of cable reinforcement have not been employed to any significant extent. This type of dead end is defined by what is commonly known as a spelter socket. A spelter socket is formed by pouring metal into a mold about a broomed or splayed end of a wire cable or rope. Typically, the cast spelter socket has a transverse hole for receiving a shackle or the like to provide means for securing the socket and cable to an object.

It has been found impractical to cast a spelter socket with the wire strands to be used as reinforcing cladding about the wire rope. One of the reasons that it is impractical to cast the wire strands with the socket is in orienting the strands properly with respect to the wire rope and mold before casting. If the strands are wrapped around the broomed or splayed end of the rope before casting, there is a tendency to collapse the splayed end, thus affecting the strength of the resultant terminal fitting in tension. On the other hand, if the wires are cast with the spelter metal such that the resulting socket has the wires anchored in it, there is difficulty in aligning the wire properly with respect to the wire rope it is to engage while not interfering with the bond of the spelter metal with the broomed section of the rope.

These problems are especially acute in the fabrication of spelter sockets because the sockets are often poured where they will be used, for example, at drilling sites.

Accordingly, there is a present need for dead ends of the spelter socket type which may be readily supplied with wire reinforcing for the wire cable or rope secured in the socket.

SUMMARY OF THE INVENTION

The present invention provides a means whereby a spelter socket may be equipped with wire reinforcing cladding to enhance the strength of the wire cable or rope where it meets the socket.

In one form, the present invention contemplates a wire cable splayed at one end. The splayed end of the wire cable is secured in a standard spelter socket when the socket is cast. A collar is provided which is disposed about the wire cable. This collar anchors a plurality of wire strands which are used to clad and reinforce the wire cable along a length thereof proximate the formed spelter socket. The collar and spelter socket are adapted for rigid attachment one to the other around the juncture point of the wire cable with the socket after the socket has been cast.

In more specific form, the present invention contemplates that the spelter socket have a thread form about the end of the socket from which the wire cable egresses. A complementary thread is provided in the collar for engagement with threads of the spelter socket. The wire strands which are anchored to the collar may then be braided along a length of the wire cable to form a cladding after the collar has been secured to the spelter socket through the complementary threads.

It is also preferred that the strands of wire be of a length at least equal to the length of the socket. It has been found that with this minimum length of cladding wire, a very effective resistance to failure from bending and torsion loads on the wire cable adjacent the socket is afforded. The enhanced failure resistance produced by the minimum length is thought to be produced by the gradual change in mass and cross-sectional area of the wire rope and its wire strand cladding as they approach the socket. This gradual change in mass and cross-sectional area greatly reduces the stress risers at the juncture of the wire rope with the socket.

It is also preferred that the cladding wire, at least that portion of the wire directly adjacent the spelter socket, be galvanized. Galvanization of the cladding wire strands offers greater resistance to corrosion of the wire cable adjacent the socket. It has been found that the wire cable may be depleted of its anodic protection in the process of its cleaning in the preparation for the pouring or casting of the spelter socket. The galvanization, then, provides an additional source of anodic material which would otherwise be sacrificed in its absence.

In terms of process, the present invention contemplates the pouring of a spelter socket about the splayed end of a wire cable or rope and then affixing a collar to the poured and cooled socket at the juncture of the wire rope with the socket. Wire cladding strands anchored to the collar are then applied about the wire cable to provide increased resistance to cable failure from bending and torsional agencies. It is preferred, as is the case in the apparatus form of the present invention, to form a thread at the end of the spelter socket which meets the unsplayed portion of the wire. A complementary thread form on the collar then provides for the ready attachment of the collar securely to the spelter socket.

The process and apparatus of the present invention provide a convenient, expeditious and effective way of strengthening wire cable at its juncture with a spelter socket. The inherent strength of the spelter socket form of wire dead ending is retained while a gradual transition of mass and cross-sectional area between the wire rope and the socket is provided. The galvanization of the wire strands enhance corrosion resistance which would otherwise be depleted by the preparation of the wire cable for the pouring of the socket. Attachment of the collar to the socket is readily accomplished through the complementary threads of each. By the independence of the collar and its anchored wire strands from the spelter socket, there is no problem in field fabrication of the spelter socket through alignment of the strands or adverse effect to the broomed or splayed end of the wire cable.

These and other features, aspects and advantages of the present invention will become more apparent from the following description, appended claims and drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a view, partly in half section, showing a preferred form of the spelter socket, collar and wire strand cladding of the present invention;

FIG. 2 illustrates the embodiment of the invention shown in FIG. 1 with the collar secured to the spelter socket; and

FIG. 3 illustrates the embodiment of the invention shown in the previous two figures, but with the wire strands wrapped about the wire cable.

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DESCRIPTION OFTHE PREFERRED EMBODIMENTS

The figures illustrate in general a spelter socket 10 which has been poured about a splayed end 14 of a wire cable 16. An internally threaded collar 18 is disposed about the wire cable. A plurality of wire strands 20 are anchored in the collar.

A wrapping 22 of wire is applied about cable 16 between the splayed or broomed portion thereof and the remainder of the cable. This wrapping prevents unnecessary splaying of cable. The spelter socket has a transverse, open passage 24 for its anchoring by a shackle or the like to an object. The socket has a generally frusto-conical lower section 26 which converges towards external socket threads 28. Threads 28 complement threads 30 of collar 18. A rounded top, generally cylindrical portion 32 of spelter socket 10, meets frusto-conical portion 26 and defines transverse passage 24. Spelter socket 10 may be of zinc alloy and is fabricated in a manner to be described.

Wire strands 20 are galvanized in order to provide anodic protection for the resultant dead end formed by the spelter socket, wire cable, collar and wire strands. It is to be noted that the anchorage of the wire strands to collar 18 is along a diameter greater than the diameter of the wire cable. This, in the formed dead end, provides for a gradual increase in mass and cross-sectional area of the wire cable and strands as they progress towards the socket. Additional gradation is effected by increasing the pitch of the wire away from the socket.

It is preferred that the wire strands be of sufficient length such that when wound on the wire cable they extend for a length at least equal to the length of the socket. This is preferred because it has been found that for such a minimum length the resistance of the wire cable to failure from torsion or bending in the vicinity of the socket is considerably enhanced. Enhanced failure resistance is believed to result from an effective transition of wire cable mass and cross-sectional area provided by the wire strands to the more massive and larger socket.

The dead end defined by the socket, wire cable, wire strands and collar is fabricated in the following manner.

After applying wire wrapping 22, wire cable 16 is splayed to define splayed section 14. Collar 18 and its depending wire strands 20 have been previously placed around the cable. With the collar and its anchored strands displaced from splayed end 14, spelter socket 10 is poured. The pouring of the socket is well known in the art but will be described briefly here. A mold of suitable configuration is provided. Molten zinc or other suitable material including zinc alloys, is poured into the mold to achieve the configuration illustrated in FIG.

1. After the socket has cooled and been removed from its mold, threads 28 may be cut.

After the threads 28 have been cut, collar 18 is secured to the spelter socket. This is illustrated in FIG. 2.

Wire strands 20 are then applied to the unsplayed portion of wire cable 16 to obtain the configurations shown in FIG. 3. The application of the wire strands to the socket may be done in a number of ways, including hand wrapping. Of course, the helix formed by the wire strands in defining the resultant wire cladding follows the helix of the wire cable. When progressive pitch is desired, however, the direction but not the pitch of the wire cable helix is followed.

The resultant dead end shown in FIG. 3, then, includes cable 16, spelter socket 10, collar 18 and the armor cladding defined by the wound or braided wire strands 20 about wire cable 16. There is an effective fatigue resisting transition of cross-sectional area and mass provided by the wire cladding from the wire cable to the socket. This desirable transition is augmented by the anchor diameter of the wire strands in collar 18 being greater than the diameter of wire cable 16. Moreover, by increasing the pitch of the wire cable away from the socket, an even greater transition is provided.

The present invention has been described with reference to certain preferred embodiments. The spirit and scope of the appended claims should not, however, be limited to the foregoing description.