Abstract:
An aerial cable spacer is provided with a cable retainer. The cable retainer includes a cable seat and a cable retaining arm. A resilient pad is secured to either or both of the cable seat and the cable retaining arm. With a cable located in the cable seat and the cable retaining arm closed upon the cable, the resilient pad is compressed and acts like a spring to maintain a force on the cable.

Description:
FIELD OF THE INVENTION 
     The invention relates to spacers for aerial cables for supporting one or more cables above the ground, and more particularly to a cable retainer for aerial cable spacers, the cable retainer having an improved clamping capability. 
     BACKGROUND OF THE INVENTION 
     Overhead conductor cables are commonly suspended from a messenger cable typically made of high strength alloys. The messenger cable is supported on poles or towers with the conductor cable spacers arranged at spaced intervals along the messenger cable to suspend one or more conductor cables. Since many power circuits require three phase electric power, it is often convenient to suspend conductor cables in groups of three. A spacer supports all three conductor cables and simultaneously maintains the conductors in spaced relation. 
     If the advantages of suspending conductors in this manner are to be fully availed, it is essential that the spacer be easily attached to the messenger cable and to the conductor cables. To provide ease of attaching the spacer to the cables and to reduce the number of parts required, the means for retaining the cables in their respective seats of the spacer should accommodate cables of varying cross sectional diameters without requiring bushings, sleeves, grommets or the like. 
     The construction of the spacer should be such that all of its parts have both high mechanical and electrical strength and are durable in use. In addition, all parts of the spacer should be economical to manufacture and to assemble. 
     U.S. Pat. No. 4,020,277 issued Apr. 26, 1977 to Hendrix Wire &amp; Cable Corporation, the predecessor to the instant assignee, and discloses a spacer for aerial cables. The spacer includes a body member having at least one generally arcuate cable retaining means adapted to engage a surface of the conductor cable and retain the cable in a concave seat of the spacer. One end of the cable retaining means is pivotally supported on the body member. Generally arcuate ratchet tooth means are provided adjacent the other end of the cable retaining means. Generally arcuate ratchet tooth means are also provided on the body member outwardly of the concave seat. The teeth of the retainer ratchet tooth means are engagable with the teeth of the body member ratchet tooth means when the retaining means is rotated about its pivotal support, thereby to firmly retain the conductor cable in the concave seat. 
     Hawkins U.S. Pat. No. 4,480,149 discloses a spacer for overheard electric lines. The cable is gripped between an inside elastomer bushing and an outside elastomer bushing. The bushing halves are compressed and held together about the conductor by a U-shaped resilient clip, which has snaps which are fitted into grooves disposed on the spacer. 
     However, it has been found in the prior art spacers that the force exerted on the cable is not satisfactory. Alternatively, it has been found that it is difficult to close the cable retainer with sufficient force exerted on the cable. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an aerial cable spacer which overcomes the above noted problems of the prior art. 
     It is a further object of the present invention is to provide an aerial cable spacer which exerts a high force on the cable. 
     It is still a further object of the present invention to provide an aerial cable spacer having a cable retainer which closes easily with a force exerted on the cable and which accommodates cables of a wide range of sizes. 
     It is yet a further object of the present invention to provide an aerial cable spacer having a cable retainer which closes easily with a force exerted on the cable and which can be used repeatedly without losing its effectiveness to retain the cable. 
     Yet a further object of the present invention is to provide an aerial cable spacer having a cable retainer which closes easily with a force exerted on the cable and which is cost effective to manufacture. 
     Still a further object of the present invention is to provide an aerial cable spacer having a cable retainer which closes easily with a force exerted on the cable and which is durable. 
     Yet still another object of the invention is to provide a cable spacer made of the same material as the cable, thereby making them dielectrically compatible. 
     The present invention therefore provides a device for supporting and spacing aerial cables, the device comprising a main body portion, the main body portion having a cable seat, the cable seat having a cable engaging surface, a first side adjacent the cable seat, and a second side adjacent the cable seat and opposite from the first side; a cable retaining arm having a cable engaging surface, a first end pivotally coupled to the second side of the main body portion, and a second end, the second end having a means for releasably engaging the first side of the main portion; and a resilient member secured to one of the cable engaging surfaces, whereby the cable retaining arm is capable of closing upon a cable positioned in the cable seat and comprising the resilient member which acts like a spring to maintain a force on the cable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of a prior art aerial cable spacer, having a plurality of cable retainers; 
     FIG. 2 is a plan view of one of the prior art cable retainers of FIG. 1; 
     FIG. 3 is a cross-sectional view of the prior art cable retainer taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is an elevational view of a cable retainer in accordance with the present invention; 
     FIG. 5 is an elevational view of the cable retainer of FIG. 4 without the cable retaining arm; and 
     FIG. 6 is a cross sectional view taken along line  6 — 6  of FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The prior art spacer shown in FIG. 1 includes the body member  10  and four generally arcuate cable retaining means  12 . The spacer secures three conductor cables  13  and is suspended by a messenger cable  14 . The conductor cable  13  includes insulating sheaths  15 . 
     Both the body member  10  and the retaining means  12  are made from a thermoplastic material, the preferred embodiment being a polymer which has a low dielectric constant and has both weather and track resistant qualities. 
     The body member  10  is provided with four hook portions  16  each having a neck portion  18 , head portion  20  and end portion  22 . The body member  10  is further provided with three generally concave conductor cable seats  24  and a generally concave messenger cable seat  26 . 
     The body member  10  is provided with four generally arcuate ratchet tooth means  28 . Each ratchet tooth means  28  is located adjacent to the sides of the respective seat  24  and  26 . Each ratchet tooth means  28  includes a plurality of teeth  30 . 
     The body also comprises semi-cylindrical sockets  32 . The sockets  32  are located adjacent to the sides of the respective seat  24  and  26 . The sockets  32  are located opposite from the respective body ratchet tooth means  28 . The sockets  32  are provided with slots  34  which are formed in part by the flanges  36  which form reinforcements for the sockets  32 . 
     Each cable retaining means  12  comprises a pair of parallel spaced generally arcuate arms  38  (FIGS.  2  and  3 ), connected together at one end by a generally cylindrical member  40  and at the other end by a transverse member  42 . The transverse member  42  is provided with a hole or perforation  44 . The transverse members  42  of the retaining means  12  are also provided with generally ratchet tooth means  46 . 
     FIG. 4 discloses the cable spacer in accordance with the present invention. Hook portion  16  is shown with the cable retaining means  12 . A cable  13  with insulating sheath  15  is secured in the cable seat  24 . The cable seat  24  includes a recess  48 . A resilient pad  50  is secured in the recess  48  using an adhesive or similar means of securing the resilient pad. The arcuate arms  38  each include a mid-portion  52  having an elbow-shaped portion  54 . Additional resilient pads  50  are also secured to the elbow-shaped portion  54  of each of the arcuate arms  38 . The additional resilient pads  50  are secured to the arcuate arms  38  using an adhesive or similar means of securing the additional adhesive pads. The resilient pads  50  may include one side with a self securing adhesive material  56 . 
     In an alternative embodiment, the present invention may consist of only one resilient pad  50  secured to the cable seat or one or more resilient pads  50  secured to the cable retaining means  12 . 
     To assemble the parts of the spacer, it is only necessary to snap each of the generally cylindrical members  40  through the slots  34  and into the respective socket  32 . 
     To install the spacer, the cable retaining means  12  are rotated to open positions in which they are temporarily retained because of the snug fit between the generally cylindrical members  40  and the respective socket  32 . The messenger cable seat  26  is then placed over the messenger cable  14  and the cable retaining means  12  adjacent to it is partially closed to hold the messenger cable  14  in its seat  26 . Then the conductor cables  13  are positioned in the seats  24 . The cable retaining means  12  are each rotated to closed positions so that the ratchet tooth means  46  engages the respective body member ratchet tooth means  28 , and the resilient pads  50  firmly contact the insulating sheaths  15  of the conductor cables  13 . Further movement of the complete retaining means  12  will be restricted due to the engagement of the resilient pads  50  with the conductor cable  13 . However, the resilient nature of the resilient pads  50  will allow a certain degree of compression. As a result, the retaining means  12  may be easily moved further in the closing direction with the engaging ratchet tooth means  46  and the body ratchet tooth means  28  locking the retaining means  12  in position with respect to the body member  10 . 
     The further movement of the retaining means  12  beyond the initial contact of the resilient pad  50  with the cables  13 ,  14  introduces a spring force in the resilient pad  50  which causes the resilient pad  50  to exert a respectively greater force on the cables  13 ,  14 . Thus the conductor cables  13  are firmly held in their respective seats  24 . The retaining means  12  for the messenger cable  14  is similarly rotated to a fully closed position so that the resilient pad  50  firmly contacts the messenger cable  14  thereby to firmly hold it in its seat  26 . 
     The holes or perforations  44  may be used to close and open the retaining means  12  by inserting a screwdriver or other elongate tool and, using the tool as a lever, either to tighten the retaining means  12  with respect to the cable  13 ,  14  or to pry it open so that it may be rotated to an open position in the event is becomes necessary to repair or replace the cables  13 ,  14 . 
     It will be apparent to persons skilled in the art that a spacer embodying this invention is new, economical to manufacture and assemble and durable in use. The spacer can accommodate a wide range of cable sizes. Furthermore, it consists of only three parts, the body  10 , resilient pad  50  and four cable retaining means  12 . The body  10  and the retaining means  12  are made of the same thermoplastic material at the same time using a single mold cut and are weather and track resistant. In addition, the cable retaining means  12  is easily closed while also providing a sufficient force on the cable  13 ,  14 . 
     While a preferred embodiment of a spacer for aerial cables embodying the invention has been shown in the drawings, it is to be understood that this disclosure is for the purpose of illustration only, and that various changes in shape, proportion and arrangement of parts as well as the substitution of equivalent elements for those shown and described herein may be made without departing from the spirit and scope of the invention as set forth in the appended claims.