Abstract:
A retractable harness system for an electrical wire having a slidable harness wire pulley, an elastic cord pulley, and an elastic cord. The slidable harness wire pulley places a rearward tension on the harness wire while allowing the harness wire to be extended and retracted from the front portion of an elongate support member. A clamp is provided capable of clamping the harness wire in fixed relation to the elongate support member, and capable of being released to allow extension and retraction of the harness wire.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority from, and the benefit of the filing date of, U.S. Provisional application Ser. No. 60/101,950, filed Sep. 25, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of systems for electrical harness wires. 
     2. Description of the Background Art 
     Many auxiliary devices and vehicles such as wagons and the like have electrical systems with an electrical harness for connecting to a source of electricity. With towable wagons, the electrical harness can extend along the tongue, so that a towing vehicle may be electrically connected to the wagon for the purposes of operating lights, brakes, control functions, etc., on the wagon. 
     There remains a need in the art for improved systems for electrical harness wires. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, disclosed is a retractable system for a harness wire which comprises a slidable harness wire pulley affixed to an elongate support member, and capable of sliding in relation to the elongated support member. It includes an elastic cord pulley fixed to a front portion of the elongate support member, and an elastic cord having a first end fixed to the front portion of the elongate support member, a second end fixed to the slidable harness wire pulley, and having a first length extending from the front portion of the elongate support member to the elastic cord pulley, passing around the elastic cord pulley, with a second length extending between the elastic cord pulley and the slidable harness wire pulley, wherein the elastic cord urges the slidable harness wire pulley toward the rear portion of the elongate support member. A harness wire is provided, which has a first length extending from the rear portion of the elongate support member to the front portion of the elongate support member, and being fixed to the front portion of the elongate support member, having a second length extending from the front portion of the elongate support member to the slidable harness wire pulley, passing around the slidable harness wire pulley, and having a third length extending from the slidable harness wire pulley to the front portion of the elongate support member. The slidable harness wire pulley places a rearward tension on the harness wire while allowing the harness wire to be extended and retracted from the front portion of the elongate support member. A clamp is provided, capable of clamping the harness wire in fixed relation to the elongate support member, and capable of being released to allow extension and retraction of the harness wire. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top elevational view of a wagon to which one embodiment of the present invention is applicable; 
     FIG. 2 is an elevational view of the operation of a spring clamp which may be used in an embodiment of the invention. 
     FIG. 3 is a perspective view of an embodiment of a wagon tongue with a retractable harness wire system in accordance with one embodiment of the present invention; 
     FIG. 4 is a perspective view of an internal tongue tube contained within the tongue of FIG. 3; 
     FIGS. 5A and 5B are elevational views of the elastic cord apparatus of the retractable harness wire in accordance with one embodiment of the present invention; 
     FIGS. 6A and 6B are elevational views of the wiring harness apparatus of the retractable harness wire; and 
     FIGS. 7A and 7B are elevational views of a spring clamp for fixing the extended length of the harness wire. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to a retractable system for an electrical harness wire. The invention may be utilized in many auxiliary devices having electrical systems which need to be connected to a source of electricity by an electrical harness wire. As one example, the invention may be utilized with a towable wagon having electrically operable electrical systems such as lights, brakes, control functions and the like, with an electrical harness wire for connecting to the electrical system of a vehicle which tows the wagon. 
     FIG. 1 shows a wagon  100  to which the present invention is applicable. Although the invention is further described herein with respect to its utilization in a wagon, it is to be understood that the invention is applicable to other devices having electrical harness wires for connecting to a source of electricity. 
     FIG. 3 shows an elongate support member in the form of a wagon tongue  300  in accordance with one embodiment of the present invention. The tongue  300  has a front portion  303  for connecting the wagon  200  to a vehicle (not shown), and a rear portion  307  for connecting the tongue  300  to a wagon frame  311  and steering linkage  314  of the wagon  200 . The tongue  300  also includes a wiring harness  322  for electrically connecting the wagon  200  to the vehicle. 
     FIG. 4 shows a tongue tube  400  which fits inside the tongue  300 . The tongue tube  400  includes several components which operate to retract and extend the wiring harness  322  from the front portion  303  of the tongue  300 . The tongue tube  400  includes an elastic cord  409 , an elastic cord pulley  412 , and a slidable harness wire pulley  416 . 
     FIGS. 5A and 5B show top and side views of the tongue tube  400 , illustrating details of the elastic cord arrangement. The elastic cord  409  is fixed at a first end at a stationary attachment point  421 . The elastic cord  409  extends from the stationary attachment point  421  up to and around the elastic cord pulley  412  and back to the slidable harness wire pulley  416 , where the elastic cord  409  is attached to attachment point  432 . 
     In operation, the elastic cord  409  opposes a forward motion of the slidable harness wire pulley  416  toward the front of the tongue tube  400 . In a preferred embodiment, the elastic cord  409  is a rubber bungee cord, but alternatively may be a spring or other elastic device. 
     FIGS. 6A and 6B show top and side views of the tongue tube  400 , illustrating details of the retractable wiring harness arrangement. The harness wire  322  extends from a rear connector  348  to a front end  318  and a front connector (not shown). The wiring harness  322  is of a length greater than needed to extend the length of the tongue  300 , with excess length being contained in the tongue. In the preferred embodiment, the rear portion of the wiring harness  322  includes a mating connector pair (including rear connector  348 ) whereby the harness section contained within the tongue  300  may be easily replaced. In a lesser preferred embodiment, the rear portion of the wiring harness  322  does not include a mating connector pair. The harness wire  322  is held at the front of the tongue  300  by a spring clamp  355 , and then passes around the slidable harness wire pulley  416  before leaving the tongue tube  400  at the front of the tongue  300 . 
     In operation, the slidable harness wire pulley  416  is biased in a rearward direction by the elastic cord  409 . The slidable harness wire pulley  416  therefore exerts a retracting force on the wiring harness  322 . During retraction of the wiring harness  322 , the slidable harness wire pulley  416  is allowed to move to the rear of the tongue tube  300 , such as shown at position  609  of FIG.  6 A. During extension of the wiring harness  322 , the slidable harness wire pulley  416  is pulled to the front of the tongue tube  300 , such as shown at positions  607  and  605  of FIG. 6A, thereby allowing more of the wiring harness  322  to extend from the tongue tube  400  and the tongue  300 . 
     FIGS. 7A and 7B show two views of a spring clamp  355  used to fix the length of the portion of the wiring harness  322  extending from the front of the tongue  300 . In the preferred embodiment, the spring clamp  355  is formed of an iron or steel rod, or a suitable substitute thereof. The rod may be between approximately one-eighth and three-quarters of an inch in diameter, and preferably is of a spring-like material. The coils  362  contribute to the spring-like characteristics. The loop  358  provides a hole through which a bolt or other fastener may be used to attach the spring clamp  355  to the tongue  300 . 
     FIG. 2 shows the spring clamp  355  in use. A wire harness, such as  817  or  819 , is pinned by the spring force of the spring clamp  355 . A soft pad  814 , such as, for example rubber, may be positioned below the claiming region of the spring clamp  355 . In use, the spring clamp  355  may be lifted in opposition to the spring force, the wire harness  817  or  819  may be moved, and the spring clamp  355  may be released in order to hold the wire harness  817  or  819  in position. 
     While the invention has been described in detail above, the invention is not intended to be limited to the specific embodiments as described. It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific embodiments described herein without departing from the inventive concepts.