GB2071750A - Gripping device for multistrand guy cable - Google Patents

Abstract

A wedging cable gripper includes a pair of wedge-shaped, peripherally recessed block sections 12 cooperatively defining a central cable- receiving bore of generally square cross section, and sliding in a complemental socket housing 14 surrounding the block sections. A pair of additional wires are applied to the cable and each has a looped portion received in corresponding block section recesses as at 90 for symmetrically bridging the blocks and securing the same to the cable. The square configuration of the cable bore yields an unexpected increase in holding power, as compared with conventional round bore blocks. The block sections are equipped with interengageable tongue and groove structure for precluding significant relative longitudinal movement thereof, and the wire-receiving peripheral recesses are angularly oriented to accommodate the looped wire portions without twisting or unnatural bending of these portions. <IMAGE>

Description

SPECIFICATION Gripping device for multi-strand guy cable Background of the Invention 1. Field of the Invention The present invention is concerned with deadending apparatus useful for terminating elongated, stranded cables of the type used for guying upright radio or utility towers. More particularly, it is concerned with such dead-ending apparatus characterized by unexpectedly high load limits and the ability to transmit gripping forces substantially evenly to the guyed cable. In this connection it has been discovered that provision of a noncircular cable-receiving bore (preferably one defined by a plurality of substantially planar, cable-engaging surfaces) in a dead-ending block yields substantial advantages, as compared with round bore blocks.

2. Description of the PriorArt Many large upright tower structures such as radio and television antennae and conductorsupporting utility towers, are erected and supported using elongated, metallic, multiple strand guy cables. Such cables are secured at their lower ends to earth anchors buried in the ground adjacent the tower site. As can be appreciated, it is critical that a secure connection be established between the ends of the guy cables and the earth anchors, especially in situations where the guyed structure is subjected to intense wind load conditions.

Stranded cables used for guying purposes are many times constructed of thickly coated wire strands which are built into a cable by stranding layers of the wire over a central core wire or wires.

Use of conventional dead-ends with such cables is less than optimum, inasmuch as such dead-ends generally do not develop the full strength of the cables, because the gripping force is not always transmitted to all of the wires of the cable; as a result, the cable is unsymmetrically loaded and cannot achieve its full rated capacity.

A number of dead-ending structures have been proposed in the past. Generally speaking, these devices include an elongated, tapered wedge block and a cooperating socket housing, the latter being operatively secured to the embedded earth anchor. A helically preformed gripping wire is normally applied to the cable and extends over the wedge block. Typical prior dead-ending devices are illustrated in U.S. Patents Nos. 4,066,368 and 3,775,811.

Summary of the invention The present dead-ending device is admirably suited for terminating coated multiple strand guying cables and serves to substantially evenly distribute gripping forces to all cable strands to thus increase the holding power of the termination. Preferably, the cable-gripping deadending device of the invention comprises a block, structure defining a cable-receiving opening in the block, including a substantially planar, cableengaging surface, and means for pressing the surface against a cable. The cable-receiving opening is preferably in the form of an elongated bore passing through the block in the central region thereof, whereas the pressing means comprises a socket housing having a complemental, block-receiving opening therein.A pair of gripping wires also forms a part of the preferred apparatus and each includes respective portions in gripping engagement with the cable and applied to the wedge block.

In more detail, the block structure advantageously is formed of separate, opposed block sections each configured to present a pair of elongated, slotted, juxtaposed, substantially planar cable-engaging surfaces oriented in a V-shaped pattern. The block sections thus cooperatively define a central cable-receiving bore which is generally square in cross section. It has been determined that this configuration unexpectedly enhances the holding power of the dead-ending apparatus, as opposed to use of a circular in cross section bore.

In further preferred embodiments, the block sections include interengageable structure (e.g., a mating tongue and groove arrangement) thereon for precluding substantial relative longitudinal shifting of the sections. In addition, the block sections include angularly oriented peripheral surface recesses for receiving respective looped portions of the gripping wire, in order to accommodate the latter without twisting or bending thereof. The recesses are of sufficient depth to preclude substantial pressing engagement between the looped wire portions and the surrounding socket housing.

Brief Description of the Drawings Figure 1 is an elevational view of a dead-ending device in accordance with the invention shown operatively installed adjacent the end of a guy cable and securing the latter to an embedded earth anchor; Fig. 2 is a sectional view illustrating the details of construction of the dead-ending device of the invention applied to a cable; Fig. 3 is a fragmentary end view with parts removed for clarity of the dead-ending device of the invention; Fig. 4 is a sectional view taken along line 4-4 of Fig. 2; Fig. 5 is a side elevational view of a wedge block section forming a part of the overall deadending device; Fig. 6 is a side elevational view of the wedge block section depicted in Fig. 5, but showing the opposite face thereof; Fig. 7 is an end view of the section illustrated in Figs. 5-6;; and Fig. 8 is an elevational view of a multiple strand gripping wire forming a part of the preferred deadending device.

Description of the Preferred Embodiment Turning now to the drawings, a dead-ending device 10 in accordance with the invention broadly includes an elongated, tapered, two-part wedge block 12, a complemental socket housing 14, and a multiple strand, continuous gripping wire 1 6. As best seen in Fig. 1, the device 10 is operable to terminate an elongated guy cable 1 8 by operatively connecting the same to the uppermost end of an embedded earth anchor 20.

In more detail, the block 12 is made up of a pair of spaced, opposed block sections 22,24. The sections 22, 24 are identical (see Figs. 5-7), and for purposes of discussion the block 22 will be specifically described. The block section 22 presents an enlarged end 26 and a smaller end 28, and tapers from end 26 to end 28 as will be readily apparent. The block section 22 further present in inner face 30 and an outer face 32 respectively illustrated in Figs. 6 and 5.

Inner face 30 is configured to present a pair of elongated, substantially planar, relatively angularly oriented cable-engaging surfaces 34, 36. These surfaces extend the full length of the block from end 26 to end 28. Inner face 30 further presents a pair of elongated, somewhat triangularly shaped, planar surfaces 38, 40 respectively joined to and extending outwardly from the associated surfaces 34, 36.

An elongated central slot 42 extends from end 28 towards end 26 between the angularly oriented surfaces 34, 36. The purpose of slot 42 is to give the block section a degree of resiliency when radially inwardly compressed.

Outer face 32 of block section 22 is configured to present an elongated, tapered, outwardly extending central rib 44 formed on both sides of the slot 42 and having a rounded shoulder at end 26. The margins of face 32 are in the form of elongated, tapered, outwardly extending ridges 46,48 which terminate in tabs 50, 52 at enlarged end 26. A pair of recesses 54, 56 are formed in face 32 between rib 44 and marginal ridges 46, 48. It is noted in this regard that the recess 54 includes a first elongated section 58 extending from end 26, and a second elongated section 60 which communicates with the section 58 and terminates at end 28. It will further be observed that the end of section 58 adjacent end 26 is rounded as at 62. Similarly, recess 56 includes a first section 64 having a rounded end 66 and proceeding from enlarged end 26 towards smaller end 28 of block 22.A second section 68 communicates with the section 64 and terminates at end 28. The sections 58, 60, and the sections 64, 68 are angularly oriented relative to one another for purposes to be made clear hereinafter.

The block sections 22, 24 preferably include interengageable structure for precluding substantial longitudinal shifting of the sections relative to one another when applied to cable 1 8.

In preferred forms, this structure includes an elongated, rectangular tongue 70 which extends outwardly from surface 40, along with a complemental groove or recess 72 provided in the ridge 46 and extending through surface 40 adjacent tab 52. As best seen in Fig. 2, the tongue 70 is received within recess 72 for interfitting of the opposed sections 22, 24.

Housing 14 is in the form of a metallic member 74 presenting a central, frustoconical bore 76 therethrough for receiving the two-piece wedge block 12. In addition, the member 74 is provided with a pair of spaced U-bolt-receiving bores 78, 80 therethrough. As best seen in Fig. 2, the bores 78, 80 are respectively disposed on opposite sides of central bore 76.

Each gripping wire (see Fig. 8) is made up of three juxtaposed, interconnected wires 82. The wires are formed to present a continuous, flattered loop portion 84 having respective legs 86, 88 and a bight portion 90. As illustrated, the legs 86, 88 merge at the closure of loop portion 84 to form a single, six wire, helically formed cable-gripping portion 92. It should be noted that the number of wires 82 may be more or less than the three wires shown in Fig. 8.

In the use of dead-ending device 10, socket housing 14 is first threaded onto cable 18 by passing the latter through central bore 76. The housing is slid up the length of the cable to a point remote from the desired termination point, so that the housing does not present an interference to application of the wedge blocks and gripping wires.

The next step involves preliminarily placing the wedge block sections 22, 24 about cable 18 in a face-to-face relationship with the respective tongues 70 being received in the corresponding recesses 72. This is accomplished manualiy in order to initially hold the block sections in place.

At this point one of the gripping wires 1 6 is applied across the block sections 22, 24. That is to say, the installer first places loop portion 84 in the elongated, arcuate recess cooperatively defined by a recess 56 on one of the 'sections and an opposed, adjacent recess 54 on the remaining section. As best seen in Figs. 2 and 3, this results in a bridging of the sections 22, 24 by the looped portion 84; that is to say, the bight 90 of the looped portion 84 engages and bridges the enlarged ends 26 of the respective wedge block sections 22, 24, while the legs 86, 88 are received in the corresponding block section recesses.The helically formed cable gripping portion 92 of the gripping wire 1 6 is then applied along the length of the cable 18 by wrapping the helices thereof about the cable in the usual manner. It will be observed in this respect that the transition from the flattened loop portion 84 to the helically formed cable gripping portion 92 is accommodated by the special, angularly configured recesses 54, 56 on the outer surfaces of the block sections 22, 24. Thus, this transition is accomplished without twisting or unnatural bending of the gripping wire 16.

The second gripping wire 1 6 is then applied to the block sections 22, 24, and to cable 18, in the manner described above. When this is accomplished, the block sections are secured to the cable 1 8 and cooperatively define a central, cable-receiving bore therethrough of generally square cross-section (see Figs. 3 and 4). The respective, elongated planar surfaces 34, 36 of each section engage the cable as illustrated.

The socket housing 14 is then slid back down the length of cable 1 8 over the applied gripping wire portions 92 and thence over the block sections 22, 24. In this connection it will be seen that the loop portions 84 of the gripping wires 1 6 are not pressingly engaged by the socket housing 14, but rather are feely received within the block section recesses. Final application of the socket housing 14 involves hammering it into solid engagement with the tapered block sections 22, 24. Specifically, (see Fig. 3) the central ribs 40, 44 and marginal ridges 46, 48 come into tight pressing engagement with the surrounding socket housing 14.

The final step in the installation of device 10 involves attaching the housing 14 to appropriate connection structure coupled to the earth anchor 20. Referring to Fig. 1, conventional U-bolt 94 is secured to the uppermost end of the earth anchor and has respective spaced apart legs 96, 98 received within corresponding socket body bores 79, 80. Nuts 100 are used to complete the connection in the well known manner. During tightening of the nuts 100, it will be appreciated that the device 10 and cable 18 are placed in substantial tension for guying purposes. Further, the block sections 22, 24 are radially compressed against the cable 18, by virtue of the central slots 42 and spacing between tapered block sections 22 and 24. In this manner a secure termination is achieved.

It has been discovered that the dead-ending device of the present invention is particularly advantageous when applied to multiple strand guying cables of the type illustrated in the drawings (see Fig. 3). In the past, termination of such cables has been difficult. Specifically, conventional dead-ending devices equipped with circular cable-receiving openings therein can create a "bridging effect" in the coated wires of multiple strand cables. That is to say, the conventional wedge blocks tend to force the wires in the outer layer of the cable to close down into a self-supporting tubular shape which precludes significant further radial pressure being transmitted to the internal strands of the cable.

This problem is overcome with the present invention, however, inasmuch as the noncircular cable-receiving bore defined by the block sections 22, 24 develops more load in the cable by forcing the outer strands thereof out of the undesirable "bridging" relationship, thereby allowing radial pressure to be exerted on the inner stands of the cable. In short, the dead-ending apparatus of the invention more evenly distributes the load through the cable, thus allowing the latter to more nearly approach its rated strength.

In actual tests comparing the preferred form of the instant invention with a wedge block having the usual circular cable-receiving bore, unexpected increases in efficiency on the order of 10 to 1 2 percent have been observed.

Claims (15)

CLAIMS Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A cable-gripping device comprising: a block; structure defining a cable-receiving opening in said block, including a substantially planar, cableengaging surface; and means for pressing said surface against said cable.

2. The device as set forth in Claim 1 wherein said opening-defining structure includes a plurality of substantially planar, cable-engaging faces.

3. The device as set forth in Claim 1 wherein said block comprises a pair of opposed block sections, said opening-defining structure including adjacent, opposed faces of said sections cooperatively defining said opening between the sections.

4. The device as set forth in Claim 3 wherein said opposed faces are each configured to present a pair of juxtaposed, substantially planar, relatively angularly oriented, cable-engaging faces.

5. The device as set forth in Claim 1 wherein said block is of elongated, tapered configuration, and said opening extends along the length of said block.

6. A cable-gripping device comprising: an elongated block; structure defining a noncircular cable-receiving opening in the central region of said block and extending along the length of the block; and means for pressing at least a portion of said opening-defining structure against said cable.

7. The device as set forth in Claim 6, said opening being located substantially at the center of said block.

8. The device as set forth in Claim 6 wherein said opening-defining structure includes at least one elongated, substantially planar, cableengaging surface.

9. A cable-gripping device, comprising: a pair of elongated, opposed block sections cooperatively configured to surround and engage a cable; interengageable structure on said block sections for precluding substantial longitudinal shifting of said sections relative to one another; and means for pressing at least respective portions of said block sections against said cable.

10. The device as set forth in Claim 9 wherein said interengageable structure includes an outwardly extending projection on one of said sections, and means defining a complemental, projection-receiving opening in the other of said sections.

1 The device as set forth in Claims 1 or 6 or 9 including gripping wire means having a first portion thereof in gripping engagement with said cable, and a second portion thereof in engagement with said block.

12. The device as set forth in Claims 1 or 6 or 9 wherein said pressing means comprises housing means surrounding and engaging said block.

13. A cable-gripping device, comprising: an elongated block including structure defining a cabie-receiving opening therein; means presenting an elongated, gripping wirereceiving recess on the outer surface of said block, said recess having at least first and second elongated sections thereof oriented at an angle relative to one another; gripping wire means having a first portion in gripping engagement with said cable, and a second portion received within said recess; and means for pressing at least a portion of said opening-defining structure against said cable.

14. The device as set forth in Claim 1 2, said pressing means comprising housing means surrounding and engaging said block, said recess being of sufficient depth to receive said second portion of gripping wire means without substantial pressing engagement between the wire and said housing means.

15. A cable-gripping device, comprising: an elongated, tapered wedge block having a central, cable-receiving opening extending along the length thereof, and a pair of elongated, gripping wire-receiving recesses formed in the outer surface thereof, said opening being defined at least in part by a plurality of elongated, generally planar, cableengaging surfaces; cable gripping means including first and second gripping wire means each having a first portion in gripping engagement with said cable, and a second looped gripping wire portion received in a corresponding recess in said block; and a socket having structure defining a tapered bore therein complementally receiving said wedge block.

1 6. The device as set forth in Claim 1 5 wherein said block comprises a pair of separate, tapered block sections each configured to present at least one of said cable-engaging surfaces and one-half of each of said recesses, the half-recesses on opposed sections being in general alignment at the largest diameter ends of the sections to cooperatively present continuous recesses, said second wire portions lying in said continuous recesses and bridging said block sections.

1 7. The device as set forth in Claim 1 6 including structure defining a groove in one of said sections, and tongue means extending from the other of said sections and received in said channel.

1 8. The device as set forth in Claim 1 5 including structure defining a pair of spaced, elongated slots respectively extending from the smallest diameter end of the block towards the largest diameter end thereof.

1 9. The device as set forth in Claim 1 5 wherein said first portion is helically formed, and said second and third portions extend from said first portion.