Abstract:
A cable includes a core and a braided synthetic tensile material. The tensile material is adapted to form a tensile member so as to longitudinally support the core when the cable is used in vertical applications. The tensile member may generally surround the core or be part of the core.

Description:
[0001]    This application claims priority to U.S. Provisional Patent Application No. 62/030,660, filed Jul. 30, 2014, the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to electrical, electronic or communication cables and, in particular, to synthetic tensile members for supporting such cables in generally vertical passageways. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a cutaway, perspective view of a cable designed for installation in generally vertical passageways; 
           [0004]      FIG. 2  is a perspective sectional view of a first embodiment of the cable having synthetic tensile members of the present invention. 
           [0005]      FIG. 3  is a perspective sectional view of a second embodiment of the cable having synthetic tensile members of the present invention. 
           [0006]      FIG. 4  is a perspective sectional view of a third embodiment of the cable having synthetic tensile members of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0007]    From time to time, it is necessary to install cables in a vertical application where the length of the cable being installed, the cable construction or the physical circumstances of the installation require that the cable include dedicated construction members for either temporarily or permanently supporting the cable length. Historically the cable weight has been supported by a number of different techniques including:
       a) steel wire armor helically applied to the cable and used to support the weight;   b) messenger wire lashed to the cable for supporting the weight; and/or   c) the use of High Tensile strength members integrated into the design of the cable core and the core covered with a layer of interlocking steel or aluminum armor. The cable is constructed so that the armor “locks” the components in place by restricting radial movement and an untwisting of the core.       
 
         [0011]    With reference to  FIG. 1 , cables specifically designed for vertical applications may feature tensile members that are used to lift the cable through a generally vertical passageway. An example of such a cable is presented in  FIG. 1 , where the tensile members  20 , typically constructed of steel, are enclosed within the cable outer jacket  22  along with conductors  24 . Conductors  24  may be replaced with members suitable for non-power applications, such as data and communication. 
         [0012]    As greater and greater depths are addressed and cables get longer and longer, the weight of the steel tensile members precludes their use. The steel weight makes the cables heavier and so larger tensile members are needed adding to its weight until there is no room left for any payload. 
         [0013]    In the embodiments of the cable of the invention illustrated in  FIGS. 2 and 3 , the individual steel tensile members ( 20  of  FIG. 1 ) are replaced by a woven braided layer of synthetic yarns. More specifically, in the embodiment of  FIG. 2 , individual strands of synthetic strand or cord  30  are braided either around a core, indicated in general at  32 , featuring multiple conductors  34  surrounded by a jacket  36 . In the embodiment of  FIG. 3 , individual strands of synthetic strand or cord  40  are braided either around a core, indicated in general at  42 , featuring a single power conductor  44  surrounded by a jacket  46 . Conductors  34  and  44  may be replaced with members suitable for non-power applications, such as data and communication. As examples only, the members may include fiber optic cables or be constructed from a metal such as copper. 
         [0014]    The jackets  36  and  46  may be extruded and, as examples only, constructed from materials that include polyvinylchloride (PVC) or nylon. 
         [0015]    In both of the embodiments of  FIGS. 2 and 3 , the braided synthetic strands or cords  30  and  40  provide longitudinal support to the core. The core ( 32  or  42 ) is gripped by the radial pressure as a result of the longitudinal stress on the braided synthetic strands or cords  30  or  40 . 
         [0016]    The synthetic strands or cords  30  or  40  preferably are made of synthetic fibers such as those sold under the trade names TECHNORA (which is a para-aramid fiber made from co-polymers) or DYNEEMA, but alternative synthetic fibers offering high strength combined with light weight may be used. Synthetic fibers additionally having high heat capacity are desirable as well. 
         [0017]      FIG. 4  illustrates an embodiment of the cable of the present invention where the cable, indicated in general at  50 , has been redesigned to eliminate the heavy steel tensile members. The steel tensile members have been replaced with synthetic light weight strength or tensile members  52 , which may be braided or woven (as shown in  FIG. 4 ). This approach reduces the overall cable weight and in some cases reduces the cable diameter. High tensile synthetic strength members may be used with armored or unarmored designs of cable. In addition, while the embodiment of  FIG. 4  illustrates multiple conductors  54 , the synthetic tensile members  52  may be used with a single conductor design. Conductors  54  may be replaced with members suitable for non-power applications, such as data and communication. As examples only, the members may include fiber optic cables or be constructed from a metal such as copper. 
         [0018]    The cable  50  of  FIG. 4  is provided with an insulating jacket  56 . The jacket  56  may be extruded and, as examples only, constructed from materials that include polyvinylchloride (PVC) or nylon. 
         [0019]    The tensile members  52  are also preferably constructed from synthetic fibers such as those sold under the trade names TECHNORA or DYNEEMA, but alternative synthetic fibers offering high strength combined with light weight may be used. Synthetic fibers additionally having high heat capacity are desirable as well. 
         [0020]    While the preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention.