Patent Publication Number: US-4731506-A

Title: Signal cable assembly

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a cable assembly, and, more particularly, to a cable assembly for transmitting an electrical signal between a power source and a load. 
     Various types of cables have been used to transfer electrical current, in some form of signal, between a power source and a load. For example, the signal from an audio amplifier is transmitted by a cable to a loudspeaker for producing a replica of a signal from a program source that is introduced to the amplifier. However, there is much controversy as to the optimum type of cable that should be used in this environment. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a signal cable which provides optimum paths for the signal being transmitted. 
     It is a further object of the present invention to provide a signal cable of the above type in which a solid conductor is provided for carrying the low frequency components of the signal and a plurality of bundles of wire strands are provided for carrying the high frequency components of the signal. 
     It is a further object of the present invention to provide a signal cable of the above type in which the bundles of wire strands are twisted into a rope-lay configuration and wrapped around the dielectric core. 
     Toward the fulfillment of these and other objects, the signal cable assembly of the present invention comprises a pair of cables each of which consists of a first conductor and a second conductor disposed in a parallel relationship. The first conductor is in the form of a plurality of bundles of wire strands twisted together to form a single conductor and the second conductor is in the form of a single solid conductor. An insulation material extends around each conductor for at least a portion of the length thereof. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The above brief description, as well as further objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of the presently preferred but nonetheless illustrative embodiment in accordance with the present invention when taken in conjunction with the accompanying drawing wherein: 
     FIG. 1 is a partial perspective view of the improved signal cable assembly of the present invention with the insulation being removed from the end portions of the cables forming the assembly; 
     FIG. 2 is a vertical cross-sectional view taken along the lines 2--2 of FIG. 1; 
     FIG. 3 is a perspective view, on a reduced scale, depicting one of the cables of the assembly of FIGS. 1 and 2 with the respective end portions of the two conductors forming the cable being twisted together for connection to a power source or load; and 
     FIG. 4 is a perspective view, on a reduced scale, of the signal cable assembly of FIGS. 1 and 2, but showing the twisting of the various conductors forming the cable assembly relative to each other. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring specifically to FIG. 1 of the drawings the reference numeral 10 refers, in general, to the improved signal cable assembly of the present invention which comprises a pair of cables 12 and 14 shown disposed in a parallel, juxtaposed relationship. The cable 12 consists of a solid conductor 16 extending immediately adjacent a conductor 18 formed by a plurality of bundles 20 of wire strands twisted together. The wire strands forming each bundle 20 are twisted in a first direction and the bundles themselves are twisted in the direction opposite the first direction. The diameter of the conductor 16 is substantially equal to the diameter of the conductor 18. 
     A pair of insulating sleeves 22 and 24 extend over the conductors 16 and 18 respectively, for the length thereof with the exception of the end portions which have been removed as shown in FIG. 1 to permit connection of the respective cables to a signal source or to a load. The cable 14 is constructed in a similar manner and, as such, includes a solid conductor 30 extending in a juxtaposed relation to a conductor 32 formed by a plurality of bundles 34 of strands twisted together to form a single conductor as in the previous embodiment. The wire strands forming each bundle 34 are twisted in a first direction and the bundles themselves are twisted in a direction opposite the first direction, also in a manner similar to that of the conductor 18. A pair of plastic flexible sleeves 36 and 38 extend over the conductors 30 and 32 respectively, and extend for the entire length thereof except for the end portions shown in FIG. 1. 
     As better shown in FIG. 2, the insulating sleeve 24 is molded to the sleeves 22 and 36 along the corresponding abutting side walls thereof while the insulating sleeve 38 is molded to the sleeves 22 and 36 also along the corresponding side walls thereof to form an integral assembly. 
     FIG. 3 depicts the cable 12 with the conductor 16 twisted around the conductor 18 to prepare the cable for connection, as a single unit, to a signal source or to a load, it being understood that the connections may be made through an appropriate terminal, terminator, connector, or the like. For example, if the cable 12 was to be connected between two audio components, such as an amplifier and a loudspeaker, the end portions of the conductors 16 and 18 would be stripped of the end portions of their respective insulating sleeves 22 and 24 and twisted together as shown in FIG. 3 before being inserted as a single unit, in the proper terminal of a five-way binding post connected to the amplifier and/or loudspeaker. It is understood that the cable 14 would be stripped, twisted, and inserted in a similar manner. The end portion of the cable 12 could be connected to the &#34;positive&#34; terminals of the amplifier and loudspeaker, respectively, while the end portions of the cable 14 could be connected to the &#34;negative&#34; terminals respectively, or visa versa. 
     It is noted that the arrangement is such that the solid conductor 16 of the cable 12 is disposed adjacent the conductor 32 formed by the wire bundles 34, of the cable 14, while the conductor 18 formed by the wire bundles 20 of the cable 12 is disposed adjacent the solid conductor 30 of the cable 14. 
     Referring to FIG. 4, after assembly in the manner described above, the respective conductors 16, 18, 30, and 32 are twisted relative to each other approximately one turn per inch as shown in FIG. 4 to inpart an overall twist to the finished cable assembly 20 as shown. 
     Several advantages result from the foregoing. For example, the wire strands forming each bundle provide an optimum path for the high frequency components of the signal, while the solid conductors form an optimum path for the low frequency components for the signal. 
     It is understood that several variations may be made in the foregoing with departing from the scope of the invention. For example, although the conductors 18 and 32 are shown as being formed by seven bundles of wire strands it is understood that this number can vary without departing from the scope of the invention. Also the conductors 16 and 30 and are not necessarily limited to a single solid conductor but can be formed by a plurality of solid conductors together forming a single cable. 
     A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention therein.