Patent Publication Number: US-6213797-B1

Title: Clockspring having non-compliant and compliant roller members

Description:
This application is a continuation-in-part of U.S. Ser. No. 09/107,108, filed Jun. 30, 1998, now U.S. Pat. No. 6,012,935 issued Jan. 11, 2000, which is a continuation-in-part of U.S. Ser. No. 08/986,866, filed Dec. 8, 1997, now U.S. Pat. No. 5,980,286 issued Nov. 9. 1999, which is a continuation-in-part of U.S. Ser. No. 08/667,634 filed Jun. 24, 1996, now U.S. Pat. No. 5,865,634 issued Feb. 2, 1999, which is a continuation of U.S. Ser. No. 08/276,954 filed Jul. 19, 1994 now abandoned. The aforementioned parent applications are hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains to a clockspring connector for enclosing electrical conductor cables. The invention more particularly concerns the clockspring connector electrically connects a rotatable electric device with a stationary electric device. 
     2. Discussion of the Background 
     While the present invention may have multiple applications, the most prevalent is for use in automobiles. An increasing number of automobiles have airbag crash systems. An airbag is typically located on the steering wheel facing the driver. The airbag must be in continuous electrical connection with sensors in the car body. The sensors provide an electrical signal to the airbag crash assembly which instantly inflates the airbag in the event of a crash. Accordingly, there is a need for an electrical connection between the rotatable portion of the airbag assembly which is mounted to the steering wheel, and the remaining portion of the assembly which is in a stationary position in the car body. Electrical connections between rotatable and stationary parts are well known. Typically, an electrical brush rests upon a conductive ring, with one of the parts being rotatable to provide such rotatable electrical connection. However, there is a risk, particularly during the impact of an accident, of a transient failure of electrical connection with a brush and ring system which result in failure of the entire airbag system crash assembly. 
     Additionally, airbags are being incorporated into seat belt chest harnesses. Thus, an electrical connection is needed between the stationary portion of the vehicle and the translating seat belt chest harness which is wound and un-wound around a rotating return axis. 
     Accordingly, a clockspring connector has previously been developed, comprising an outer housing, a rotor member and a multiple of intermediate housing members for enclosing and connecting the members; the housing and rotor member rotatably associated with one another at a plurality of bearing surfaces. A “clockspring” is located inside the interconnector. The clockspring of prior art devices includes a single flat conductor cable having its ends conductively attached to conductor wires which pass out of the interconnector to unite the airbag to the sensing device. For example, U.S. Pat. No. 5,061,195 discloses a clockspring housing and assembly having a single flat conductor cable therein. 
     It has also been known in the art to reduce the length of the flat conductor cable in order to reduce cost and needed space within the clockspring housing. For example, U.S. Pat. No. 5,277,604 incorporates an assembly of at least eight rollers and turned-back portions of the flat conductor cable within the clockspring housing to decrease the length of the flat cable and also prevent buckling and enhance reliability and smooth rotation of the clockspring connector. Such a design requires a complex and expensive system of mounting the rollers. Such a design may be expensive and, as well, only accommodates a single flat conductor cable. 
     The use of a pair of conductor cables was disclosed in U.S. Pat. No. 3,763,455. The conductor cables were carried by an assembly of twenty spacers or rollers. This design also requires a multiplicity of parts, including numerous rollers which add to the assembly time and costs of the device. 
     As more controls are mounted on the steering wheel, more conductors are required to pass multiple electrical signals through the clockspring connector. Prior art clocksprings have included conductor cables having up to six conductors in each flat cable. The excess of six conductors is limited by the limited width of the flat conductor cable and the processing methods of manufacturing the flat cable. Accordingly, there is needed a clockspring connector which can accommodate more than six conductors. 
     Still further, assembling clocksprings is a laborious and costly process that is prone to error. In particular, the known art requires that the clockspring be assembled from an assortment of components that guide flat ribbon cables in sync with the rotation of the steering wheel. Assembling the various components individually into a clockspring is a tedious and labor intensive process. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide for a clockspring that may readily be assembled and manufactured. 
     It is still another object of the invention to provide for an integrated carrier assembly having a frame and which easily assembles within a steering wheel. 
     It is another object of the present invention to provide a clockspring connector having a minimal amount of moving parts. 
     It is a further object of the present invention to provide a clockspring connector having flat conductor cable of minimal length. 
     It is another object of the present invention to provide a clockspring having a freely and independently rotating carrier member. 
     It is a further object of the present invention to provide a clockspring connector that reduces vibration of the flat conductor cable by use of a compliant roller member. 
     It is yet another object of the invention to provide a durable clockspring. 
     The above objects and advantages are provided by a clockspring connector comprising a housing defining a chamber extending therethrough. A carrier member positioned within the chamber having a hard roller member and a plurality of complaint roller members. A flat conductor cable being carried by the carrier member. The flat conductor cable having a turned-back portion associated with the hard roller member. A hub having an inner diameter exit cavity for receiving the flat conductor cable. The housing member receives the hub, the carrier member is mounted on the hub, and a cover encloses the carrier member and flat flexible cable within the housing. The cover having an outer diameter exit cavity. 
     In an alternative embodiment of the invention, the clockspring provides for the housing to include a carrier assembly rotatably mounted thereto. The housing itself includes a fixed cover and a base that define a chamber. The carrier assembly preferably comprises a frame having one or more rollers that rotate independently. Within the housing, an inner diameter region is concentrically defined by a hub and the frame, and an outer diameter region is concentrically defined by the frame and the housing. The first and second flat ribbon cables are variably distributed to encircle the hub along either the inner or outer diameter regions. The flat ribbon cables pass and turn-back through the rollers of the frame, so that the portions of each flat ribbon cables located in the inner and outer diameter regions move in opposite directions. Each flat ribbon cable includes a slack length that passes through a corresponding roller or roller pair to vary the distribution of the flat ribbon cable between the inner and outer diameter. A hard roller member being positioned at a concave surface of the turned-back portion of one of the flexible flat cables and a compliant roller member being positioned at a convex surface of the flexible flat cable at the turned-back portion. The first and second flat ribbon cables interconnect to an inner backbone, as incorporated by previous embodiments, that is received by the base and accessible to each flat ribbon cable from the inner diameter region. An outer backbone is also accessible to each flat ribbon cable along the outer diameter region, such that the flat ribbon cables may interconnect the inner and outer backbone within the clockspring. In this way, rotation of the inner backbone causes the flat ribbon cables to contact and rotate the integrated carrier assembly. In particular, the slack length of each flat ribbon cable may contact a roller and rotate the integrated carrier assembly in conjunction with the intake or outtake of flat ribbon cable. Preferably, the slack length of each flat ribbon cable may contact one or the other roller forming a roller pair that receives each flat ribbon cable, thereby forcing the integrated carrier assembly to rotate in either the clockwise or counterclockwise direction. 
     These and other features of the invention are set forth below in the following detailed description of the presently preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of a clockspring connector; 
     FIG. 2 is a top view of a clockspring connector in a fully wound position; and 
     FIG. 3 is a top view of clockspring connector in a fully unwound position; 
     FIG. 4 is a top view of an alternate embodiment of a clockspring connector; 
     FIG. 5 is an enlarged view of a compliant roller member of FIG. 4; 
     FIG. 6 is a side cut-away view of the clockspring connector of FIG. 4 taken along section line  6 — 6 ; 
     FIG. 7 is a top view of a clockspring embodiment of an alternative integrated carrier assembly in the unwound position; 
     FIG. 8 is a top view of another alternate embodiment of a clockspring connector; 
     FIG. 9 is an enlarged view of a compliant roller member of FIG. 8; 
     FIG. 10 is a side cut-away view of the clockspring connector and compliant roller member of FIG. 9 taken along section line  10 — 10 ; 
     FIG. 11 is a side cut-away view of the clockspring connector and hard roller member of FIG. 8 taken along section line  11 — 11 ; and 
     FIG. 12 is a top view of a clockspring embodiment of an alternative integrated carrier assembly in the unwound position. 
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIGS. 8-12 thereof, a clockspring having a hard roller member and compliant roller members has been created which provides for clockspring performance that is quiet and durable. Firstly, however, the embodiments disclosed in FIGS. 1-7 are discussed so as to introduce and set the stage for the embodiments discussed in FIGS. 8-12. 
     The clockspring connector is better understood by reference to FIGS. 1-3 which show various aspects of a clockspring connector. Turning to FIG. 1, a housing  10  receives a hub  20 . Mounted on the hub  20  is a carrier member  30 . A first flat conductor cable  41  and a second flat conductor cable  42  is carried by the carrier member  30 . A cover  50  encloses the flat ribbon cables  41 ,  42 , carrier member  30  and hub  20  within housing  10 . 
     The housing  10  includes a ledge  12  upon which the base  22  of hub  20  rests. The hub  20  and housing  10  are constructed of materials which allow the hub  20  to freely rotate within the housing  10  and to reduce the amount of friction between the base  22  and ledge  12  to the greatest extent. Materials such as a teflon tape, silicon material or grease may be inserted between the base  22  and ledge  12  in order to reduce friction at these bearing surfaces and all other bearing surfaces of the present invention. An inner diameter exit cavity  24  protrudes downwardly from the base  22  of hub  20 . Inserted within the inner diameter exit cavity  24  is an inner diameter backbone  26 . The inner diameter backbone  26  receives flat conductor cable at its entrance end  27  and insulated wires  28  protrude from the exit end  29 . 
     Mounted on the hub  20  and freely and independently rotatable thereon is carrier member  30 . The carrier member  30  is generally a circularly shaped member being molded of a thermoplastic polymer material. However, any material may be used to form the carrier member  30 . The carrier member  30  includes a first roller mounting area  37  and a second roller mounting area  38 . Axles  33 ,  34  protrude upwardly from the roller mounting areas  37 ,  38 , respectively. Roller area walls  35 ,  36  surround the roller areas  37 ,  38  and are correspondingly shaped to the outer diameter of first roller  31  and second roller  32 . Inner diameter corner  65  and outer diameter corner  66  are located at each end of roller area walls  35 ,  36 . The total circumference of roller area walls  35 ,  36  may be controlled by changing the shape of comers  65 ,  66  in order to control the path of the conductor cables  41 ,  42 . By rounding comers  65 ,  66 , the circumference of walls  35 ,  36  is reduced and the area which contacts the conductor cables  41 ,  42  is also reduced. By extending and bringing comers  65 ,  66  to a point, the circumference of walls  35 ,  36  is increased which increases the surface area which contacts conductor cables  41 ,  42 . 
     First roller  31  is mounted on axle  33  and second roller  32  is mounted on axle  34  of the carrier member  30 . The first and second rollers  31 ,  32  rotate freely and independently on their axles  33 ,  34 . A multiplicity of nubs  39   a  and  39   b  protrude from around the carrier member  30  toward the hub  20  or housing wall  15  and provide a surface against which the conductor cables  41 ,  42  may rub and rotate against. The carrier member  30  provides a member for mounting rollers  31 ,  32  and separating the conductor cables  41 ,  42  along the outer diameter of the chamber  14  from the conductor cables  41 ,  42  at the inner diameter of the chamber  14 . Spring members  62  are molded into the carrier member  30 . Spacers  64  protrude from spring members  62  and help to keep the carrier member  30  positioned axially within the clockspring housing chamber  14 . The housing chamber  14  is defined by the housing wall  15  around the circumference of the housing  10 . The chamber  14  is further defined by the hub base  22  at its bottom and cover  50  at the top. 
     The clockspring includes two flat conductor cables  41 ,  42 . A first conductor cable  41  and second conductor cable  42  are adjacently coiled around carrier member  30  within chamber  14  of the housing  10 . The flat ribbon cables  41 ,  42  are formed by laminating six conductors parallel to each other with a pair of insulating films one each side. The use of two flat ribbon cables  41 ,  42  having six conductors each provides for a total of twelve conductors carried by the clockspring. However, more than two conductor cables could be carried in order to increase the number of conductors to an almost limitless combination. The first conductor cable  41  includes first turned-back U-shaped loop section  43  and second conductor cable  42  includes second turned-back U-shaped loop section  44 . First and second conductor cables  41 ,  42  exit the clockspring at the outer diameter through the outer diameter exit cavity  52 . Conductor cable tails  46  are folded perpendicularly to the path of the conductor cables within the chamber  14  and are received by the outer diameter exit cavity  52 . Outer diameter backbone  54  is received from the other end of the outer diameter exit cavity  52  from the conductor cable tails  46 . Entrance cavity  56  of the outer diameter backbone  54  receives the first and second conductor cables  41 ,  42 . The conductors of the cables  41 ,  42  are welded to the corresponding insulated wires  58  which protrude from the exit end  59  of outer diameter backbone  54 . 
     Assembly of the clockspring connector having the hub  20  adjacent the housing  10  occurs in order to allow for the easiest and quickest possible assembly of the clockspring connector. While the hub  20  includes the exit cavity  24  at the inner diameter, the hub  20  is the rotatable member which is associated with the steering wheel of an automobile. Rotation of the steering wheel of the automobile simultaneously rotates the hub  20 . The cover  50  having exit cavity  52  at its outer diameter is placed onto the housing  10  and is the stationary member of the clockspring connector. The exit cavity  52  at the outer diameter is associated with the steering column of an automobile and is stationary. Thus, although FIG. 1 shows assembly of the clockspring connector having the inner diameter exit cavity  24  on the bottom and the outer diameter exit cavity  52  at the top of the assembly; when the clockspring connector is assembled to a steering assembly, it will be inverted so that the inner diameter exit cavity  24  and hub  20  are on the top of the clockspring connector and the outer diameter exit cavity  52  and cover  50  are on the bottom of the clockspring connector. 
     Operation of the clockspring can more easily be understood by viewing FIG.  2 . The housing  10  has mounted therein carrier member  30  and hub  20 . Mounted on the carrier member  30  is first roller  31  and second roller  32 . The clockspring connector is shown in the fully wound position having the majority of the conductor cables  41 ,  42  coiled around the hub  20  at the inner diameter of the chamber  14 . First roller  31  is mounted in roller area  37  on axle  33  of the carrier member  30 . Second roller  32  is mounted in second roller area  38  on axle  34  of the carrier member  30 . First conductor cable  41  exits the outer diameter backbone  54  and coils adjacent to the outer diameter wall  15  of the housing  10 . First turned-back loop section  43  then coils around first roller  31  and then coils around the hub  20 . Second flat conductor cable  42  exits the outer diameter backbone  52  and at second turned-back loop  44 , coils around second roller  32  and then onto hub  20  from the opposite side, 180° from the position where the first conductor cable  41  coils onto the hub  20 . First conductor cable  41 ′ terminates at the inner diameter backbone  26  adjacent second flat conductor cable  42 ′. 
     The rotational movement of the steering wheel is transmitted to the clockspring connector through the hub  20  and inner diameter backbone  26 . Rotation in the clockwise direction or in direction of arrows  70 ,  71  causes the first flat conductor cable  41  to unwind off of hub  20  and move to the right at position  100  and rub against wall  35  of the first roller area  37  of the carrier member  30 . Simultaneously, second flat conductor cable  42  unwinds from hub  20  at point  102  and protrudes and rubs against wall  36  of second roller area  38  of carrier member  30 . As the hub continues to unwind in the clockwise direction, the conductor cables  41 ,  42  push against walls  35 ,  36  and force the carrier member  30  also to rotate clockwise. As the hub  20  and carrier member  30  rotate clockwise, the first flat conductor cable  41  is spooled out from first roller  31  to completely encircle the outer diameter of the chamber  14  adjacent the wall  15  of the housing  10 . Simultaneously, the second flat conductor  42  is spooled out along second roller  32  at a position 180° from the first conductor cable  41 , to provide a second coil layered adjacently to the first conductor cable  41  at the outer diameter of the chamber  14 . Rotation of the hub  20  and carrier member  30  continue in the clockwise direction until the flat cables  41 ,  42  are completely unwound from the hub  10 . 
     The completely unwound condition is shown in FIG.  3 . Like numerals for like elements of FIG. 2 are shown in FIG.  3 . The clockspring connector  5  is shown in a completely unwound position, i.e., the flat conductor cables  41 ,  42  are not coiled around hub  20 . To wind the clockspring connector  5 , the hub  20  is rotated in a counter-clockwise direction in the direction of arrows  72 ,  73 . Upon rotation of the hub  20  in a counter-clockwise direction, the first flat cable  41  pulls on the first roller  31  at first turned-back loop  43  causing the first roller  31  to rotate. Simultaneously, second conductor cable  42  pulls on second roller  32  at second turned-back loop  44  causing the second roller  32  to rotate in clockwise direction. The pulling of the first cable  41  and the second cable  42  on the first and second rollers  31 ,  32  causes the carrier member  30  to rotate in a counter-clockwise direction. As the hub  20  and carrier member  30  continue to rotate counter-clockwise, the first and second conductors  41 ,  42  are uncoiled from the outer diameter of the chamber  14  and become coiled again onto the hub  20 . It can be seen that in the completely unwound position, the coils are positioned along the outer diameter of the chamber  14  in a first layer  81 , a second layer  82 , a third layer  83 , and a fourth layer  84 . The first conductor cable  41  and the second conductor cable  42  are alternatingly layered; wherein first layer  81  and third layer  83  are the first conductor cable  41  and the second layer  82  and fourth layer  84  are the second conductor cable  42 . Upon the first rotation of the hub  20  in the counter-clockwise direction, layer  81  is taken up from the outer diameter of the chamber onto the hub  20  by first roller  31 . Simultaneously, second layer  82  is taken up by second roller  32 . Upon a second rotation, third layer  83  is taken up by the continued rotation of first roller  31  in the counter-clockwise direction and fourth layer  84  is taken up by second roller  32 . This alternating take-up sequence is correspondingly achieved along the inner diameter of the chamber  14  by winding the clockspring connector in the clockwise direction spooling first and second conductor cables  41 ,  42  onto the hub  20 . 
     Turning to FIG. 4 an alternate clockspring  103  embodiment is shown including a housing  110  having a hub  120 . Mounted on the hub  120  is a carrier member  130 . A first flat conductor cable  141  is carried by the carrier member  130 . A cover encloses the carrier member  130  and hub  120  within the housing  110 . The housing  110  is constructed of materials which allow the hub  120  to freely rotate within the housing  110  and to reduce the amount of friction between the base  122  of the housing  110 . Material such as teflon tape, silicon material or grease may be inserted between the base  122  and the housing  110  in order to reduce the friction at these bearing surfaces. Similarly, such materials may be used to reduce friction between the carrier member  130  and the housing  110 . An inner diameter exit area  126  receives the flat conductor cable  141  and the tape or flat conductor cable is attached to a backbone (not shown) which connects the flat conductor cable to external electrical wires. 
     The carrier member  130  is generally a hollow cylindrically shaped member molded of a thermoplastic polymer material. However, any material may be used to form the carrier member  130 . The carrier member  130  includes a first roller mounting area  137  and a second roller mounting area  187 . In an embodiment the carrier member  130  may include six roller mounting areas and six roller members  131 . However, any number of roller mounting areas and rollers can be used. Axles  133  protrude upwardly from the roller mounting area  137 . Roller area walls  135 ,  136  surround the roller areas  137  and are correspondingly cylindrically shaped to the outer diameter of the roller member  131 . The roller member  131  is mounted on axle  133  and is retained on the axle by arm  160 . The arm  160  is integrally molded with the axle  133 . The arm  160  extends out from the axle  133  beyond the inner-diameter of the roller member  131 . The roller member  131  is formed of a elastic, compliant material such as rubber or neoprene. The complaint material allows the roller member  131  to maximize the compression forces that are applied against the flat ribbon cable  141  thus urging the ribbon cable  141  against the outer wall of the chamber  182  and the inner wall of the chamber. For example, a rubber O-ring manufactured by Apple Rubber Products, Inc. is used in an embodiment and has durometer measure of 70 and a diameter of 19.5 mm and provides a compression force of 0.15 grams against the flat ribbon cable  141  when the roller member  131  is deformed by less than 20% of its original, undeformed shape. The diameter of the roller member  131  is approximately equal to the width of the chamber  182  ±0.100 inch. The width of the chamber is defined by the shortest distance between the inner wall  152  and outer wall  151  of the housing  110 . 
     In another embodiment the roller member  131  maybe formed of a low friction and rigid material at its inner diameter and a high friction and compliant material along its outer diameter. The roller having a multiple composition provides for maximum friction against the flat ribbon cable  141  while allowing for some compression. Having the rigid material at the center of the roller member eliminates the possibility of permanent deformation of the roller member  131 . The roller member  131  rotates freely and independently on the axle  133  due to the lubricity of the mating materials. The orientation of multiple roller members mounted on the carrier member  130  provides for a continuous compression of the flat ribbon cable  141  against the inner wall  152  and outer wall  151  around the entire diameter of the clockspring housing  110 . The roller members  131  have an outer diameter approximately equal to the width between the inner wall  152  and outer wall  151 . The roller member  131  in the first roller area  137  also provides the function of a turn back loop in order to guide the flat ribbon cable  141  in a U-shape from the hub  120  through the first roller area  137  and turning back to be guided along the outer wall  151 . The clockspring shown in FIG. 4 discloses only a single flat ribbon cable  141 . However, in an alternative embodiment the present design may also incorporate multiple flat ribbon cables being carried by the carrier member  130  and the roller members  131 . 
     The clockspring  110  in FIG. 4 is shown in the full counter-clockwise position having the flat ribbon cable  141  spooled onto the outer wall  151  of the housing  110 . As the hub  120  is rotated in a clockwise direction the flat ribbon cable  141  moves through the first roller area  137  and is coiled onto the inner wall  152  of the hub  120 . As the flat ribbon cable  141  moves from being coiled onto the outer wall  151  to the inner wall  152  the thickness of the coil tape on the outer wall  151  is reduced and the thickness of the coiled flat ribbon cable  141  on the inner wall  152  is increased. In other words the gap between the roller member  131  and the inner and outer walls  151 ,  152  changes as the flat ribbon cable  141  is spooled from the outer wall  151  to the inner wall  152 . Although the gap between the roller member  131  and the walls  151 ,  152  varies, the compliant roller member  131  maintains a constant compression against the flat ribbon cable  141 , regardless of how many layers of the coiled flat ribbon cable are located on either the outer or inner wall  151 ,  152 . This procedure is reversed when the hub  120  is rotated in the counter-clockwise direction. 
     Turning to FIG. 5, an enlarged view of second roller area  187  is shown. The roller member  131  is mounted on axle  133  and is maintained thereon by arms  160 ,  161 . The roller member  131  is mounted on carrier member  130  which is mounted within the housing  110  of the clockspring between the outer wall  151  and inner wall  152 . The flat ribbon cable  141  is shown having a first layer  191  and a second layer  192  coiled against the outer wall  151  of the housing  110 . The two coiled layers  191  and  192  of the flat ribbon cable  141  cause the roller member  131  to compress and form an ovoid shape. The diametral distance measured from where points of the roller member  131  contact the inner and outer walls  151 ,  152  being is less than the diametral distance measured between points of the roller member  131  at points  201  and  202  where the roller member  131  is adjacent the roller area walls  136 ,  137 . The roller member  131  is also offset toward the inner wall  152  so that the inner diameter of the roller member  131  forms a first gap  210  between the inner diameter of the roller member  131  and the axle  133  that is greater than a second gap  211  formed between the inner diameter of the roller member and the axle  133 . In a preferred embodiment the roller member  131  includes an inner diameter radius that is larger than the radius of the axle  133 , so that such an offset condition may be achieved. Consequently, when the hub  120  is rotated and the flat ribbon cable  141  is coiled on the inner wall  152 , the roller member  131  will be offset in the other direction toward the outer wall  151  and the first gap  210  will be less than the second gap  211 . Similarly, the ovoid shape of the roller member  131  will be maintained in order to continue to provide compression of the roller member  131  against the flat ribbon cable  141  coiled onto the inner wall  152  of the housing  110 . Therefore, it may be understood throughout the entire rotation of the hub and the winding and the unwinding of the flat ribbon cable  141  a constant pressure will be applied against the flat ribbon cable  141  compressing it against either the inner  152  or outer  151  wall of the housing  110 . This improved system provides for a quiet clockspring operation which avoids vibrations of the flat ribbon cable  141  that cause noise. 
     Turning to FIG. 6 a side elevation cut-away view of FIG. 4 taken at line  6 — 6  is shown. The housing  110  is shown having hub  120  mounted thereon forming a cavity  182  in which the carrier member  130  is mounted. Roller member  131  is mounted on axle  133  and maintained thereon by arms  161 ,  162 . As the clockspring is in its full counter-clockwise position, multiple layers of the flat ribbon cable  141  are coiled along outer wall  151  and a single coil of the flat ribbon cable  145  is located along inner wall  152  of the housing  110 . In this orientation it can be seen that the first gap  210  between the inner diameter of the roller member  131  and the outer diameter of a first side  191  the axle  133  is greater than the second gap  211  on the opposed second side  192  of the axle  133 . As discussed above, the roller member  131  being formed of a compliant material provides for the roller member  131  providing a constant compression force against the flat ribbon cable  141 ,  145  throughout the unwinding and winding of the flat ribbon cable onto the inner wall  151  to the outer wall  151  of the clockspring housing  110 . 
     It can be seen that two flat conductor cables can be easily wound with minimal components incorporated within the clockspring housing and with minimal length of flat conductor cable. 
     In still another clockspring  203  embodiment, FIG. 7 shows an integrated carrier assembly  230  for employing rotatably mounted rollers to guide one or more flat ribbon cables. The integrated carrier assembly  230  differs from previous embodiments in that it includes preassembled components integrated as one unit for assembly purposes. As will be described in greater detail, the integrated carrier assembly  230  of the preferred embodiment includes a frame  260  with rollers or roller assemblies mounted thereto. As with previous embodiments, the integrated carrier assembly  230  resides with a chamber  214  defined by the clockspring housing  210 . The preferred integrated carrier assembly  230  includes a frame  260  having pairs of rollers for guiding the flat ribbon cables thereto. In general, the integrated carrier assembly  230  operates in similar fashion to previous clocksprings described herein. Accordingly, FIG. 7 shows that the integrated carrier assembly  230  rotatably mounts to the hub  220 , with the cover  250  fixedly mounted over the housing  210  to enclose the hub  220  and integrated carrier assembly  230 . The housing  210  is also constructed of materials which allow the hub  220  to freely rotate therein in a manner that reduces friction between the base (shown as numeral  22  in FIG. 1) and housing  210 . To this end, materials such as Teflon tape, silicon material or conventional grease may be injected between the base  222  and the housing  210 . In similar fashion, the integrated carrier assembly  230  is rotatably secured to the housing  210  on the hub  220 . 
     With further reference to FIG. 7, the frame  260  surrounds the hub  220  and supports a plurality of rotatably attached rollers that maintain a guiding presence on the flat ribbon cables  240 ,  241 . The frame  260  is oblong and contoured to extend across the chamber  214 , with one or more roller assemblies employing rollers that guide the flat ribbon cables  240 ,  241 . In the preferred embodiment, a first and second pair of rollers  231 ,  231  and  232 ,  232  oppose one another across the frame  260 , with each pair of rollers comprising two adjacent rollers. However, it should be readily apparent to one skilled in the art that more or less rollers may be used in similar or alternative arrangements. The rollers are rotatably secured to the frame  260  by corresponding first and second connector forks  238 ,  238  and  239 ,  239  that unitarily extend from the frame  260  and engage each roller  231  and  232  about the axle to allow free rotation. For reference, an inner diameter region may be defined as the concentric area between the integrated carrier assembly  230  and hub  220 , while the outer diameter region is defined as the concentric area between the housing  210  and integrated carrier assembly  230 . The rollers  231 ,  232  spool the flat ribbon cables  240 ,  241  from the inner diameter region to the outer diameter region and thereback. Preferably, the rollers comprise solid plastic, but may also include compliant rollers discussed elsewhere in this application may be substituted in this embodiment. 
     As with previous embodiments, the flat ribbon cables  240 ,  241  electrically connect two conductive backbones or conductive surfaces within the housing, where the first backbone is received by the base and is rotatable therewith to transmit the motion of the steering wheel. For purposes of this particular embodiment, the ribbon cables  240 ,  241  connect the inner diameter backbone  226  with the outer diameter backbone  254 , in a manner described with previous embodiments herein. Each flat ribbon cable  240 ,  241  is distributed to include a portion within the inner and outer diameters, where each flat ribbon may pass and turn-back through the roller assemblies  231 ,  232  to distribute their respective lengths between the inner and outer diameters. In this way, when the flat ribbon cables  240 ,  241  distribute upon rotation of the inner backbone  226 , the portions of the respective flat ribbon cables  240 ,  241 within the inner and outer diameter each move in opposite directions with respect to one another. Each flat ribbon cable  240 ,  241  may also have a slack portion that is variable with rotation of the inner backbone  226 , and is defined approximately to be the cable length positioned at any given moment between the rollers of each roller assembly  231 ,  232 . With rotation of the inner backbone  226 , the flat ribbon cables  240 ,  241  increasingly distribute between the inner or outer diameter region, depending on whether the clockspring is being wound or unwound. FIG. 7 shows in greater detail one preferred configuration of the clockspring, with the flat ribbon cables  240 ,  241  in the unwound position such that the amount of each flat ribbon cable  240 ,  241  is maximized along the outer diameter region. 
     Since the arrangement of flat ribbon cables  240 ,  241  may equally be shared between the inner and outer diameter regions, the embodiment will be described with reference to the wound position depicted in FIG.  7 . It should be apparent to one skilled in the art that the distribution and motion of the flat ribbon cable  240 ,  241  from the wound to the unwound position is substantially similar or equivalent to FIGS. 2 and 3 and the accompanying text. This embodiment varies from previous embodiments by providing an improved mechanism for guiding and supporting one or more flat ribbon cables within the housing. Accordingly, FIG. 7 shows that each flat ribbon cables  240 ,  241  may interconnect with the inner backbone  226  to partially encircle the hub  220  along the inner diameter. Both flat ribbon cables  240 ,  241  interconnect with the inner backbone  226 , and extend to and encircle about the outer diameter from opposing ends of the frame  260 . As such, the flat ribbon cable  241  is shown to be longer than the other cable to provide for the extra length needed to encircle the hub  220  an extra 180 degrees. 
     As with previous embodiments, rotation of the steering wheel allows the inner backbone  226  to force the flat ribbon cables  240 ,  241  to variably distribute among the inner or outer diameter regions. With respect to the embodiment of FIG. 7, the steering wheel may be rotated in the clockwise direction to wind the flat ribbon cables  240 ,  241  about the hub  220 . The winding motion forces the excess flat ribbon cables  240 ,  241  through the respective pair of rollers  231 ,  231 , and  232 ,  232 . In general, each flat ribbon cable  240 ,  241  slackens as it passes through the respective rollers  231 ,  231  and  232 ,  232 . The slack length in turn forcibly engages the roller pairs and thereby provides a reactive force that rotates the carrier member  230  in conjunction with the rotation of the inner backbone  226 . In this way, the motion of the carrier member  230  positions the rollers  231 ,  231 , and  232 ,  232  to intake the flat ribbon cable from the outer diameter region, so that the flat ribbon cables  240 ,  241  cannot pinch or radially pull inwards with successive rotations of the inner backbone. In this way, the flat ribbon cables  240 ,  241  may be fully wound from the unwound position about the hub  220 , such that all excess cable resides in the inner diameter region. 
     It should be apparent to one skilled in the art that while the flat ribbon cables  240 ,  241  are preferably slack when passing through the respective rollers  231 ,  232 , a taught engagement between the rollers and flat ribbon cables  240 ,  241  is also contemplated. In a taught engagement, each flat ribbon cable  240 ,  241  pulls one of the rollers in the pair of rollers  231 ,  232  as it passes from the outer to the inner diameter region, with little excess slack forming between the rollers. The pulling motion of the flat ribbon cables  240 ,  241  through the rollers  231  and  232  also causes the reactive force that rotates the integrated carrier assembly  230  in conjunction with the intake of flat ribbon cables. 
     Based on the configuration of FIG. 7, the flat ribbon cables  240 ,  241  unwind from the inner diameter when the inner backbone  226  is rotated in the counterclockwise direction. The counterclockwise rotation of the clockspring pushes the flat ribbon cables  240 ,  241  to unwind from the inside to the outside diameter regions. The unwinding rotation causes the flat ribbon cables  240 ,  241  to slack while passing through rollers  231 ,  231  and  232 ,  232 . In turn, the pushing motion of the flat ribbon cables  240 ,  241  causes the respective slack lengths to combine and forcibly contact the roller pairs and/or the integrated carrier assembly  230 , thereby rotating the integrated carrier assembly  230  in the counterclockwise motion. In this way, the inner backbone  226  may be rotated in the clockwise or counter clockwise direction to variably distribute the excess length of each flat ribbon cable  240 ,  241  to and from the inner and outer diameter regions. 
     As with previous embodiments, this embodiment provides for the flat ribbon cables  240 ,  241  to radially compress and reduce the sliding friction that cause noise. However, this embodiment provides one significant improvement over the prior art in that it provides for the flat ribbon cables  240 ,  241  to compress only within the inner diameter region. As such, this embodiment avoids the creation of folds and fracture points that tend to form when the flat ribbon cables are comprised along the outer diameter region. More specifically, the flat ribbon cables  240 ,  241  are confined within the small concentric space between the frame  260  and hub  220 , which allows the flat ribbon cables  240 ,  241  to compress against one another and the frame/hub within the inner diameter region. In this manner, the invention reduces the amount of noise that often results from transferring the flat ribbon cables  240 ,  241  between the inner and outer diameter regions. 
     A method of assembling the clockspring of this invention is also provided for this embodiment. The method includes providing a housing having a fixed cover and a rotatable base, the housing receiving a first and second conductive backbone, the first conductive backbone received by the base to be rotatable therewith and with the steering system. In addition, the method includes rotatably mounting the hub  220  to the housing  210  to be freely rotatable with respect to the housing, and rotatably mounting the integrated carrier assembly  230  to be freely rotatable with respect to the hub  220  and the housing  210 . The method of further includes distributing the first flat ribbon cable  240  in the housing  210  to interconnect the first and second backbone so that a portion of the first flat ribbon cable is distributed in the region between the frame and the hub, and another portion of the flat ribbon cable is distributed between the housing and the frame. The method may also include distributing a second flat ribbon cable  241  in substantially similar fashion, and for compressing the first and second flat ribbon cable  240 ,  241  against the hub with the frame  260 . The flat ribbon cables may be compressed by dimensioning the frame  260  with respect to the hub  220  to provide for the inner diameter region therebetween to be sufficiently narrow to compress each flat ribbon cable. Finally, the method of assembly may provide for securing the assembled clockspring to a steering system in a manner known and practiced in the art. 
     While this embodiment preferably employs a design with two flat ribbon cables, it should be readily apparent to one skilled in the art that the integrated carrier assembly  230  may accommodate a single flat ribbon cables design by providing only one pair of rollers. Likewise, additional roller pairs may be employed to incorporate three or more flat ribbon cables in the clockspring. The use of more or less flat ribbon cables is generally dictated by the number of closed circuits required within the steering wheel, and not by limitations of this invention. 
     Thus, Applicants&#39; previous embodiments included clocksprings having roller members which were all hard and other embodiments included clocksprings having roller members which were all compliant. 
     Briefly, problems exist with current clockspring designs that have resulted in rubbing or scraping of the internal parts of the clockspring, which manifests itself as noise, wear on the components, and increased parasitic torque which must be overcome when turning the steering wheel. Noise emanating from the clockspring is a major complaint of occupants in the passenger compartment of automobiles. 
     The clockspring structure according to the present invention greatly reduces the amount of rubbing and scrapping of internal components of the clockspring. Thus, providing for a clockspring which is more quiet than previous clockspring designs. 
     Applicants have found, hard roller members are substantially rigid and as such they maintain the flat flexible cable in well established locations, however, backlash or clearance exists between the hard roller members, the flat flexible cable, and the walls of the housing, thus increasing noise, but decreases torque. Additionally, the hard roller members have excellent resistance against wear and in conjunction with the polyester insulating layers of the flat flexible cable exhibit excellent lubricity thus reducing friction. 
     Applicants have found, compliant roller members in conjunction with the polyester insulating layer of the flat flexible cable exhibit large amounts of friction between the two surfaces thus the compliant roller members urge the flat flexible cable against the housing of the clockspring, thus the compliant roller members provide for quiet operation of the clockspring. However, the torque required to rotate the hub relative to the housing is increased. Additionally, the compliant roller member located at the turned-back portion of the flat flexible cable becomes worn with use and the conductors of the flat flexible cable are susceptible to breakage due to the non-constant radius provided by the compliant roller member. 
     Applicants have combined the best features of the preceding embodiments and have provided for a clockspring which is durable, quiet, and has low residual torque. FIGS. 8-11 show a preferred embodiment of the invention. FIG. 8 is a top plan view of the clockspring  303  of the invention. Clockspring  303  is similar to clockspring  103  shown in FIGS. 4-6 except that clockspring  303  has a hard, non-compliant or substantially rigid roller member  331  located at the turn-backed portion of the flexible flat cable  141 . The remaining roller members are compliant roller members  131  which conform to the previous description of such roller members in the previous embodiment. 
     The hard roller member  331  is made of a nylon or acetal. A preferred material of construction is an acetal homopolymer sold under the trade name DELRIN and produced by E.I. du Pont de Nemours and Company. The hard or substantially rigid roller member  331  provides excellent stiffness, dimensional stability, strength, resistance against wear, and superior lubricity when sliding against flat flexible cable. 
     FIG. 11 is an enlarged cross-sectional view of the hard roller member  331  taken along section line  11 — 11  of FIG.  8 . Axles  133  protrude upwardly from the roller mounting area  137  (shown in FIG.  8 ). Roller area walls  135 ,  136  (shown in FIG. 8) surround the roller areas  137  and are correspondingly cylindrically shaped to the outer diameter of the hard roller member  331 . FIG. 11 clearly shows the clearance present between the inside diameter of the hard roller member  331  and the outside diameter of the axle  133 . The materials of construction of the axle  133  and of the hard roller member  331  are such that a great amount of lubricity is present between the two parts. Thus, even when the flexible flat cable  141  pushes the hard roller member  331  against the axle  133 , the hard roller member  331  and the axle  133  slide relative to each other without being impeded with much friction. Furthermore, even when the flexible flat cable  141  pushes the hard roller member  331  against the axle  133 , the outer radius of the hard roller member  331  contacts the flexible flat cable  141  and not the arms  160 ,  161 ,  162 . Since the hard roller member  331  is substantially rigid it maintains the flexible flat cable  141  to a nearly constant radius in the region of the turned-back portion. As such the conductors of the flexible flat cable  141  are exposed to uniform amounts of bending and thus the fatigue failures of the conductors are reduced and the operational life of the clockspring is extended. Additionally, the outside diameter of the hard roller member  331  is smaller than the outside diameter of the compliant roller members  131 . The outside diameter dimension of the hard roller member  331  is dimensioned so as to provide clearance between the walls  151 ,  152  of the chamber  182 , and the flexible flat cables  141 , 142 . 
     As shown in FIG. 8, the hard roller member  331  is mounted on axle  133  and is retained on the axle by arm  160 . The arm  160  is integrally molded with the axle  133 . The arm  160  extends out from the axle  133  beyond the inner-diameter of the roller member  331 . Since the hard roller member  331  is substantially rigid, the hard roller member  331  is rocked or pivoted so as to have its inside diameter to pass by the arm  160 . 
     Turning to FIG. 9, an enlarged view of second roller area  187  is shown. The roller member  131  is mounted on axle  133  and is maintained thereon by arms  160 ,  161 . The roller member  131  is mounted on carrier member  130  which is mounted within the housing  110  of the clockspring between the outer wall  151  and inner wall  152 . The flat ribbon cable  141  is shown having a first layer  191  and a second layer  192  coiled against the outer wall  151  of the housing  110 . The two coiled layers  191  and  192  of the flat ribbon cable  141  cause the roller member  131  to compress and form an ovoid shape. The diametral distance measured from where points of the roller member  131  contact the inner and outer walls  151 ,  152  being is less than the diametral distance measured between points of the roller member  131  at points  201  and  202  where the roller member  131  is adjacent the roller area walls  136 ,  137 . The roller member  131  is also offset toward the inner wall  152  so that the inner diameter of the roller member  131  forms a first gap  210  between the inner diameter of the roller member  131  and the axle  133  that is greater than a second gap  211  formed between the inner diameter of the roller member and the axle  133 . In a preferred embodiment the roller member  131  includes an inner diameter radius that is larger than the radius of the axle  133 , so that such an offset condition may be achieved. Consequently, when the hub  120  is rotated and the flat ribbon cable  141  is coiled on the inner wall  152 , the roller member  131  will be offset in the other direction toward the outer wall  151  and the first gap  210  will be less than the second gap  211 . Similarly, the ovoid shape of the roller member  131  will be maintained in order to continue to provide compression of the roller member  131  against the flat ribbon cable  141  coiled onto the inner wall  152  of the housing  110 . Therefore, it may be understood throughout the entire rotation of the hub and the winding and the unwinding of the flat ribbon cable  141  a constant pressure will be applied against the flat ribbon cable  141  compressing it against either the inner  152  or outer  151  wall of the housing  110 . This improved system provides for a quiet clockspring operation which avoids vibrations of the flat ribbon cable  141  that cause noise. 
     Turning to FIG. 10, a side elevation cut-away view of FIG. 9 taken along section line  10 — 10  is shown. The housing  110  is shown having hub  120  mounted thereon forming a cavity  182  in which the carrier member  130  is mounted. Roller member  131  is mounted on axle  133  and maintained thereon by arms  161 ,  162 . As the clockspring is in its full counterclockwise position, multiple layers of the flat ribbon cable  141  are coiled along outer wall  151  and none of the flat ribbon cable  145  is located along inner wall  152  of the housing  110 . In this orientation it can be seen that the first gap  210  between the inner diameter of the roller member  131  and the outer diameter of a first side  191  the axle  133  is greater than the second gap  211  on the opposed second side  192  of the axle  133 . As discussed above, the roller member  131  being formed of a compliant material provides for the roller member  131  providing a constant compression force against the flat ribbon cable  141 ,  145  throughout the unwinding and winding of the flat ribbon cable onto the inner wall  151  to the outer wall  151  of the clockspring housing  110 . In a preferred embodiment, as discussed earlier, the compliant roller has a durometer measurement of  70 . 
     In still another clockspring embodiment, FIG. 12 shows an integrated carrier assembly  230  for employing rotatably mounted rollers to guide one or more flat ribbon cables. The clockspring  403  is almost the same as clockspring  203  shown in FIG.  7 . The assembly and mode of operation of the two clocksprings  203 ,  403  are the same. The difference between the two clocksprings is the design of the roller members. The clockspring  203  of FIG. 7 has roller members  231 ,  232  which are made of a rigid plastic. In FIG. 12, the clockspring  403  has substantially rigid or hard roller members  431 ,  432  at the turned-back portion of the flat ribbon cables  240 ,  241 . The difference between the clocksprings exists in the use of complaint roller members  433 ,  434  which are made of a compliant material such as rubber or neoprene. The compliant roller members  433 ,  434  can be made of a hard material that has an outer coating of compliant material. The hard roller members  431 ,  432  are preferably made of DELRIN. 
     The hard roller members  431 ,  432  operate the same way as the hard roller members of clockspring  203  shown in FIG.  7  and the same as the hard roller member  331  shown in FIGS. 8-11. Hard roller member  431  is attached to connector fork  239 . Hard roller member  432  is attached to connector fork  238 . Compliant roller member  433  is attached to connector fork  239 . Compliant roller member  434  is attached to connector fork  238 . 
     The compliant roller members  433 ,  434  provide the ability to press the flat ribbon cables  240 ,  241  against the inner wall at the outer diameter of the housing  210 . Thus, noise is kept to a minimum since the flat ribbon cables  240 ,  241  are not able to move and vibrate in the vicinity of the compliant roller members  433 ,  434 . Additionally, as an option, the compliant roller members  433 ,  434  can be oversized so as to place the flat ribbon cables  240 ,  241  in a state of compression at the inner wall at the inner diameter of the housing (not shown). 
     As shown in FIG. 12 the hard roller member  431  faces and opposes the compliant roller member  433 . Hard roller member  431  faces and is adjacent to a concave surface of the first flat ribbon cable at the turned-back portion. Compliant roller member  433  faces and is adjacent to a convex surface of the first flat ribbon cable at the turned-back portion. The function and positioning of hard roller member  432 , compliant roller member  434 , and the second flat ribbon cable are similar. 
     When the hub  220  or backbone  226  is rotated in a clockwise direction, when looking at FIG. 12, the backbone  226  pulls the first and second flat ribbon cables in a clock-wise direction. The first flat ribbon cable imparts a force on the hard roller member facing the concave surface of the first flat ribbon cable and thus causes the integrated carrier assembly  230  to rotate in the clock-wise direction. 
     When the backbone  226  of the hub  220  is rotated in a second direction opposite to the first direction, i.e. counter-clock-wise, the backbone  226  rotates in a counter-clock-wise direction which rotates the first flat ribbon cable  240  in a counterclock-wise direction. The convex surface of the first flat ribbon cable  240  imparts a force on the compliant roller member facing the convex surface. Thus, the integrated carrier assembly  230  is then caused to rotate in the counter-clockwise direction. The rolling of the first and second flat ribbon cables against the compliant roller members  433 ,  434  greatly reduces the sliding and rubbing of components within the clockspring. Thus, the design greatly reduces the amount of noise emanating from the clockspring. Conversely, the rolling and sliding of the first and second flat ribbon cables against the hard roller members  431 ,  432  increases sliding and rolling between the flat ribbon cables and the hard roller members and hence reduces friction and thus reduces parasitic torque. Additionally, the hard roller members  431 ,  432  maintain a nearly constant radius at the turned-back portion, thus the flat ribbon cables have a longer life since the conductors will not break as often. Thus, the clockspring  403  greatly reduces the amount of noise emanating from the clockspring and increases the durability of the clockspring. 
     While this embodiment preferably employs a design with two flat ribbon cables, it should be readily apparent to one skilled in the art that the integrated carrier assembly  230  may accommodate a single flat ribbon cables design by providing only one pair of rollers. Likewise, additional roller pairs may be employed to incorporate three or more flat ribbon cables in the clockspring. The use of more or less flat ribbon cables is generally dictated by the number of closed circuits required within the steering wheel, and not by limitations of this invention. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.