Abstract:
A modular rotary anvil for an ultrasonic welding machine, comprising of a shaft, and a plurality of spaced inserts coupled to the shaft, each of the inserts extending from the shaft substantially the same distance, and being configured to engage a workpiece, wherein at least one of the inserts has a peripheral textured surface pattern, and another one of the inserts has a peripheral smooth surface pattern.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional application of U.S. patent application Ser. No. 10/975,349, filed Oct. 29, 2004, which is a divisional application of co-pending U.S. patent application Ser. No. 10/442,294, filed May 21, 2003, which is a divisional application of U.S. patent application Ser. No. 09/454,333, filed Dec. 3, 1999, now U.S. Pat. No. 6,841,735, which is a continuation-in-part application of U.S. patent application Ser. Number No. 08/627,136, filed Apr. 3, 1996, now U.S. Pat. No. 6,026,563, and claims priority to and hereby incorporates herein by reference the same. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention pertains to flat cable and an apparatus for making flat cable. The invention more particularly concerns flat electrical cable with exposed conductors without adhesive residue and a modular rotary anvil which is used to manufacture the flat electrical cable.  
       BACKGROUND OF THE INVENTION  
       [0003]     Flat electrical cables are well known in the art as having conductors sandwiched between two insulating layers. Flat conductor cable is known in the art as having an upper insulator layer having an adhesive adhered to a first side of the upper layer and a lower layer of insulating material having an adhesive adhered to a first side of the lower layer. A conductor or strands of conductors are placed between the upper and lower insulator layers and all three layers are secured together by the adhesive. However, use of adhesive to bond the layers is disadvantageous in that upon heating of the adhesive, the conductors may float in the free flowing adhesive causing the spacing between the conductors to be inconsistent and non-parallel. Upon drying and attempted attachment of the flat cable to a component, the improperly placed conductor may not align with the conductive leads of the component the cable is to be attached and, thus, the flat cable is unusable and must be discarded. Further, when the cable is stripped to expose the conductors for connection of the cable to a component, the conductors have an adhesive residue thereon which inhibits the conductive properties of the conductor. Also, if any scrap material of the insulator layers is produced, the scrap may not be recycled due to the presence of the adhesive on the insulator layer.  
         [0004]     Other bonding techniques are known in the art for bonding multiple layers such as ultrasonic welding. Generally ultrasonic welding has been used for spot welding with thermoplastic materials using either a plunge mode or a shear mode. Therefore, the known methods of welding thermoplastic materials using ultrasonics did not provide for a continuous welded seam where the seam has great pull strength. In the area of electrical cables, seams of great pull strength are required and the previously known welding techniques are not sufficient.  
         [0005]     The ultrasonic welding apparatus includes an ultrasonic welding machine  1 , as shown in  FIGS. 14 and 15 . The ultrasonic welding machine  1  includes inner and outer brackets  2  and  3 , the anvil frame  4 , the horn  5 , the pattern roller or rotary anvil  6  mounted to the anvil frame  4 , a chain  7  to rotate the rotary anvil  6 . However, other methods of rotating the rotary anvil  6  can be used. Socket head cap screws  8  attach the outer bracket  3  to the anvil frame  4 . The rotary anvil  6  is mounted in opposition to the horn  5 . As shown, in  FIGS. 14 and 15 , the work-piece (not shown) is fed into and through the gap  9  present between the horn  5  and the rotary anvil  6 . As the horn  5  plunges or shears against the work-piece, the rotary anvil  6  remains rigid in the opposing direction of the force and subsequent impacting of the work-piece by the horn  5 , thus reacting the forces generated by the process. In this example, as shown in  FIGS. 14 and 15 , the horn  5  does not rotate. As such, no pattern is formed on the side of the work-piece facing the horn  5 , if the surface of the horn is flat and smooth. As the work-piece passes through the gap  9  between the horn  5  and the rotary anvil  6 , the rotary anvil  6  rotates. Thus, a pattern can be imprinted on the surface of the work-piece. Such a method of manufacture requires that a unique anvil be created and inventoried for every type of and size of pattern desired to be formed on the work-piece.  
       SUMMARY OF THE INVENTION  
       [0006]     Therefore, it is an object of the present invention to provide a flat electrical cable which is bonded without use of adhesives and provides for a continuous seam.  
         [0007]     It is another object of the invention to provide a flat electrical cable that is light in weight.  
         [0008]     It is still another object of the invention to provide a flat electrical cable that has a high natural frequency.  
         [0009]     It is a further object of the invention to reduce the number of tools required to be kept in inventory for producing the flat electrical cable.  
         [0010]     It is another object of the invention to increase the variety of tool sets being run at the same time.  
         [0011]     It is an additional object of the invention to support flexible manufacturing of flat electrical cable.  
         [0012]     It is another object of the invention to provide a method of assembling a flat cable by bonding without using adhesives and to provide the capability of forming a continuous seam and other types of seams.  
         [0013]     It is a further object of the present invention to provide a flat cable having exposed conductors without an adhesive residue.  
         [0014]     It is another object of the present invention to provide a flat electrical cable which operates quietly during use in a clockspring.  
         [0015]     It is a further object of the invention to provide a durable flat electrical cable.  
         [0016]     It is still another object of the invention to provide a flat electrical cable which carries a large amount of current for a long period of time.  
         [0017]     It is still a further object of the invention to provide a flat electrical cable which conveys many functions such as pulse heating to a steering wheel.  
         [0018]     It is still another object of the invention to provide a flat cable having multiple types of conductors, conductor groups, or optical fibers.  
         [0019]     It is yet another object of the invention to provide for a low cost flat electrical cable.  
         [0020]     A principal object of this invention is to provide a flat electrical cable comprising an upper insulator layer, a lower insulator layer connected to the upper layer, a lower insulator layer connected to the upper layer along substantially continuous parallel spaced-apart seams and an intermediate layer comprised of individual strands of conductors which lie adjacent and substantially parallel to the seams and the conductors do not have an adhesive residue thereon. The upper layer may include a plurality of raised surfaces running parallel to each other along the length of the flat cable. The lower layer may be substantially planar and include a pattern formed on the majority of the surface of the lower layer. Seams positioned between adjacent conductors have a textured surface pattern, and seams positioned along edges of the flat electrical cable have a substantially smooth surface pattern. The upper and lower insulator layers may be polyester. The conductors may be copper. The seams may be ultrasonically welded. The conductors may be exposed at an end portion of the flat cable beyond the upper and lower insulator layers. The cable may include a continuous seam except for a nonbonded area where the upper and lower insulator layers are not connected. The cable may include a continuous seam except for a nonbonded area where the upper and lower insulator layers include windows that expose the conductors.  
         [0021]     In still another embodiment of the invention, a flat cable is provided comprising an upper insulator layer, a lower insulator layer, and an intermediate layer. The lower insulator layer connected to the upper insulator layer along substantially continuous parallel spaced apart seams. The intermediate layer comprised of conductor groups which lie adjacent and substantially parallel to the seams. Furthermore, the conductor groups do not have an adhesive residue on their outer surface.  
         [0022]     In another embodiment of the invention, a flat electrical cable is provided comprising an upper lam of polyester having a ribbed surface, a lower layer of polyester connected to the upper layer along substantially continuous parallel spaced-apart ultrasonically bonded seams and individual strands of copper conductors lying substantially parallel and adjacent to the seams between the upper and lower layers. The lower layer may have a pattern along the majority of its exposed surface. Seams positioned between adjacent conductors have a textured surface pattern, and seams positioned along edges of the flat electrical cable have a substantially smooth surface pattern.  
         [0023]     In another embodiment of the invention, a clockspring is provided for electrically connecting an airbag in a steering wheel of a vehicle through a steering column to crash sensors, the clockspriing comprising a housing having an inner chamber and a flat electrical cable including an upper insulator layer, a lower insulator layer connected to the upper layer along substantially continuous parallel spaced-apart seams and an intermediate layer comprised of individual strands of conductors which lie adjacent and substantially parallel to the seams and the conductors do not have an adhesive residue thereon, the flat electrical cable being mounted in the chamber of the clockspring. Seams positioned between adjacent conductors have a textured surface pattern, and seams positioned along edges of the flat electrical cable may have a substantially smooth surface pattern.  
         [0024]     In a further embodiment of the invention, a modular rotary anvil for an ultrasonic welding machine is provided comprising a first end segment, a second end segment, and a at least one insert having a first side and a second side, each of the first side and the second side configured to attach to at least one of other inserts, the first end segment, and the second end segment. The first end segment and the second end segment configured to attach to the ultrasonic welding machine.  
         [0025]     In another embodiment the invention takes the form of a method of assembling a flat electrical cable. The steps of producing the flat electrical cable include simultaneously feeding an upper and lower layer of insulating material and an intermediate layer of conductors between a horn and a modular rotary anvil, and the next step being ultrasonically bonding the upper and lower layers together along a seam substantially adjacent the conductors.  
         [0026]     In still yet another embodiment the invention takes the form of a method of assembling a clockspring. The steps of producing the clockspring include inserting a flat cable into a clockspring housing, where the flat cable is made pursuant to the method steps recited in the paragraph above.  
         [0027]     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  
       [0028]     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:  
         [0029]      FIG. 1  is a perspective view of the flat cable of the present invention;  
         [0030]      FIG. 2  is a side-elevation view of the preferred apparatus for bonding of the flat cable;  
         [0031]      FIG. 3  is an enlarged view of the bonding area of  FIG. 2 ;  
         [0032]      FIG. 4  is a side-elevation view of the assembly machinery and process of the present invention;  
         [0033]      FIG. 5  is a perspective view of an alternate embodiment of the flat cable of the present invention showing the flat electrical cable after the end portion has been stripped to expose the conductors;  
         [0034]      FIG. 6  is an enlarged view of the bonding area of  FIG. 2  where a modular rotary anvil is shown being used with a horn moving in a plunging action;  
         [0035]      FIG. 7  is a perspective view of an alternate embodiment of the flat cable of the invention which was formed with the use of the modular rotary anvil;  
         [0036]      FIG. 8A  is a front view of one embodiment of the modular rotary anvil;  
         [0037]      FIG. 8B  is an expanded detailed view of  FIG. 8A ;  
         [0038]      FIG. 9A  is a front view of another embodiment of the modular rotary anvil;  
         [0039]      FIG. 9B  is an expanded detailed view of  FIG. 9A ;  
         [0040]     FIGS  10 A and  10 B are a side view and a front view of a large bracket insert from  FIG. 8A ;  
         [0041]      FIGS. 11A and 11B  are a side view and a front view of a small bracket insert from  FIG. 8A ;  
         [0042]      FIGS. 12A and 12B  are a side view and a front view of one knurled insert from  FIG. 8A ;  
         [0043]      FIGS. 13A and 13B  are a side view and a front view of one smooth seam insert from  FIG. 8A ;  
         [0044]      FIG. 14  is an exploded side view of a related ultrasonic welding machine;  
         [0045]      FIG. 15  is a side view of an assembled, related, ultrasonic welding machine of  FIG. 14 ;  
         [0046]      FIG. 16  is a perspective view of another alternate embodiment of the flat cable of the invention which was formed with the use of the modular rotary anvil;  
         [0047]      FIG. 17  is an expanded view of a portion of an alternate knurl pattern;  
         [0048]      FIG. 18  is an end view of a single conductor;  
         [0049]      FIG. 19  is an end view of dual or tandem conductors;  
         [0050]      FIG. 20  is an end view of dual stacked conductors;  
         [0051]      FIG. 21  is an end view of tripled stacked conductors;  
         [0052]      FIG. 22  is an end view of a wire rope conductor;  
         [0053]      FIG. 23  is an end view of a compressed wire rope conductor;  
         [0054]      FIG. 24  is an exploded, perspective view of a single flat conductor assembled with upper and lower insulation layers;  
         [0055]      FIG. 25  is an exploded, perspective view of a dual tandem conductor group assembled with upper and lower insulation layers;  
         [0056]      FIG. 26  is an exploded, perspective view of a triple stacked conductor group assembled with upper and lower insulation layers;  
         [0057]      FIG. 27  is an exploded, perspective view of a dual stacked conductor group assembled with upper and lower insulation layers; and  
         [0058]      FIG. 28  is an exploded, perspective view of a wire rope conductor group assembled with upper and lower insulation layers. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0059]     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to  FIG. 1  thereof which shows a finished flat conductor cable  10  of a preferred embodiment of the present invention. The flat cable  10  has an upper layer  20  and a lower layer  30  formed of an insulating material. In a preferred embodiment, polyester insulator is used, such as that having a thickness of 0.001 inches. However, thicker insulator materials may be used to provide stronger bonds, such as where the seams are narrow. Intermediate the upper and lower layers  20 ,  30  are conductors  40 . The conductors  40  are made of individual strands of metallic material which lie substantially parallel to one and another along the length of the cable  10 . In a preferred embodiment, the conductors are formed of annealed copper having a dead soft hardness rating. However, any other conductor may be used such as copper clad steel. Furthermore, the conductor can be replaced with a fiber optic cable. The conductors  40  are separated by seams  50 . The seams  50  are formed by the continuous bonding between the upper layer  20  and the lower insulator layer  30 . A plurality of parallel spaced-apart seams  50  run continuously along the length of the cable  10 . In a preferred embodiment, the spacing between the plurality of conductors  40  comprises the seams  50 . In other words, the width of each seam  50  approximately equals the space between the adjacent conductors  40 . In such a construction, the conductors  40  are trapped in a pocket or encapsulated between the seams  50  and the upper and lower insulator layers  20 ,  30  to avoid any shorting between the parallel strands of conductors  40 . In a preferred embodiment, the seams  50  are ultrasonically bonded, which will be discussed further below.  
         [0060]     The cable  10  includes a raised surface  25  or ribs above the conductors  40  on the upper layer  20  of the insulator. The raised surface  25  provides for a ribbed texture along the upper surface  20  of the cable  10  and reduces the surface area of the upper layer  20  so that less friction is created when the upper layer  20  rubs against another surface. In an embodiment where the flat cable  10  is wound in a spool, the noise of the surface of the upper layer  20  of the flat cable  10  rubbing against the lower layer  30  will be reduced due to the ribs  25 . In addition, in another embodiment, the lower layer  30  of the flat cable  10  has a pattern  35  adhered thereto. The pattern  35  acts to reduce the surface area of the most extraneous portions of the lower layer  30  in order to further reduce friction and noise of the lower layer  30  rubbing against another surface.  
         [0061]     In the preferred method of assembling the flat cable  10 , the bonding of the upper and lower layers  20 ,  30  occurs only at the plurality of seams  50  and no bonding of the upper layer  20  or lower layer  30  occurs to the conductors  40 . In such an arrangement, the conductors  40  are bounded on each side by the seams  50  but are loose in the compartment formed by the upper and lower layers  20 ,  30  which are not bonded in the area along the length of the conductor  40 . This arrangement provides an advantage in that when the end of the cable  10  is stripped and the conductors  40  are exposed, the exposure operation is simplified in that there is no bonding between the conductors  40  and the upper or lower layers  20 ,  30 . Therefore, there is no residue on the conductors  40  and cleaning of the conductors is not required in order to provide the desired level of conductivity. An edge  15  of the flat cable  10  is also bonded and has a continuous seam such as provided by an ultrasonic weld. This edge  15  may be provided by cutting the flat cable  10  via slitting station  89  shown in  FIG. 4 . The edge  15  produced by cutting is a smooth edge or surface. The smooth surface of the edge  15  results in a flat electrical cable which provides for quiet operation during use in a clockspring, even though the edge  15  contacts sound damping material of the clockspring housing.  
         [0062]     In the preferred embodiment, the seam  50  is continuous and runs along the entire length of the cable  10 . The preferred use of the flat electrical cable  10  of the present invention is in an automobile clockspring which provides for the electrical connection of the airbag of an automobile steering wheel through the steering column to stationary crash sensors in the automobile. In such clocksprings, the flat ribbon cable is wound around an inner chamber of the clockspring housing and generally has a length of approximately two feet. In the process described below, the flat cable is formed continuously in spools of over one-thousand feet or any desired length. The spool of cable is later cut to two feet lengths and the ends of the two feet lengths are stripped. In the preferred embodiment of the invention, the overall length of the seams will be equal to the length of the entire spool of cable, as the seams  50  are continuous.  
         [0063]     In an alternate embodiment, the seam may be noncontinuous at the separation areas of the cable  10 . Thus, the majority of the length of the cable  10  has a continuous seam  50  except at the end of that portion of the cable having a desired length to be used and attached to a component. For example, at two feet intervals along the length of the cable  10  a narrow nonbonded separation area may be formed. The nonbonded areas are located at the point along the cable where it is intended that the flat cable will be cut or separated. A nonbonded area will be formed every two feet of the cable so that the end portions of the two foot lengths of the flat cable  10  will have small areas, for example, one inch lengths, which are nonbonded. In this way, the ends of the cable may be easily processed in order to expose the conductors  50 . Having the nonbonded areas allows for the top and bottom layers to easily be clipped or cut to expose the conductors  40 . In the previously mentioned embodiment having completely continuous seams, the desired lengths of the flat cable must be inserted in a grinding or buffing machine in order to remove the layers of insulation and expose the conductors or cut the insulator layers from between the conductors. The method of forming the nonbonded areas at specific intervals along cable will be discussed further below.  
         [0064]     An alternate embodiment of the present invention may be provided having multiple layers of insulating material and conductors therebetween. Additional layers may include ground wires or a ground plane or a drain wire or additional layers to limit cross talk.  
         [0065]     The method of assembling the flat cable of the present invention is best understood with reference to  FIGS. 2-7 . One specific bonding process will be discussed with reference to  FIGS. 2, 3  and  6  and the overall process with reference to  FIG. 4 . Turning to  FIG. 2 , a rotary horn  60  is shown having weld surface  65 . Adjacent the rotary horn  60  is rotary anvil  70 . The rotary anvil  70  rotates about axis  71  and rotary horn  60  rotates about axis  61 . The rotary horn  60  provides for the ultrasonic bonding of the flat cable which is inserted between the rotary horn  60  and the rotary anvil  70 . In a preferred embodiment, a full wave rotating horn of titanium is used in order to provide for a weld surface  65  of greater than one inch. In a preferred embodiment, the weld surface  65  is three inches wide. The three inch wide weld surface  65  is preferred so that the maximum footage of flat cable  10  may be produced. Although in the preferred embodiment of the end use of the cable  10  widths are approximately one-half inch, the three inches wide weld surface  65  allows for the simultaneous assembly of six cables side-by-side, to be separated later. The three inch weld surface  65  provides for the maximum width without sacrificing a uniform amplitude level of the rotary horn  60  so that the ultrasonic bond strength is maintained. In one embodiment, the full wave horn  60  provides for ultrasonic bonding via a shear mode or in the horizontal direction of arrow  67 . The use of the full wave horn having a shear mode provides for continuous welding to form a continuous seam  50  of the flat cable  10 . As is known in the ultrasonic bonding art, the rotary horn  60  is attached to a converter and a booster which generates a voltage which creates a wave which passes through the rotary horn  60  and causes the rotary horn  60  to oscillate or vibrate in the direction of arrow  67 . In one embodiment, the horn will vibrate at approximately 20 kHz. However, the horn can be vibrated at frequencies in the range of 30 or 40 kHz. Furthermore, the rotary horn  60  can be vibrated in the plunge mode, as is described below.  
         [0066]     Turning to  FIG. 3 , an enlarged view of the  FIG. 2  shows the bonding area between the weld surface  65  of the rotary horn  60  and the rotary anvil  70 . The rotary anvil  70  includes a plurality of copper locating grooves  72  and interspersed between the grooves  72  are protrusions  74 . The flat cable is fed between the weld surface  65  of the rotary horn  60  and the rotary anvil  70  at gap  68  so that the upper insulator layer  20  is adjacent the rotary anvil  70  and the lower layer  30  is adjacent the rotary horn  60 . The grooves  72  and protrusions  74  of the rotary anvil  70  are designed and oriented according to the specific arrangement and spacing of conductors desired in the flat cable. In the embodiment shown in  FIG. 3 , the rotary anvil  70  has been designed to form a flat cable having six conductors as can be seen by the group of six grooves  72 . The rotary horn  70  is designed so that a batch of flat cables are formed simultaneously side-by-side which may be separated later during the assembly process. The broad protrusion  75  provides for a broad space in order to allow for the separation of individual flat cables. In a preferred embodiment, the anvil and weld surface  65  of the rotary horn  60  are designed to make six individual cables simultaneously side-by-side, each having six conductors. In the present embodiment, the entire bonding surface between the weld surface  65  of the rotary horn and the rotary anvil  70  is three inches wide. Each individual flat cable is approximately half of an inch wide and therefore, six individual cables can be formed simultaneously and later split in order to form the individual flat cables. Therefore, in the preferred embodiment, the rotary anvil  70  will have five wide protrusion areas  75  in order to form six separate areas having six grooves  72  to form each individual flat cable having six conductors therein. The grooves  72  have a width just slightly larger than the width of the connductors being bonded within the flat cable. In the preferred embodiment, the width of the grooves  72  is 0.045 inches. The spacing of the conductors is determined by the width of the protrusion  74 . In the preferred embodiment, the protrusions  74  all have the same width of approximately 0.0338 inches. However, all these dimensions may vary dependent on the overall design and requirements of cable desired. In an embodiment, the rotary anvil  70  may be interchangeable with other rotary anvils having different spacing of the grooves  72  and protrusions  74  to assemble a flat cable having differently spaced conductors. In a preferred embodiment, as discussed below, the rotary anvil  70  takes the form of a modular rotary anvil  70   a  as shown in  FIG. 6 , where multiple rotary anvils  70  are not required to be on hand to produce flat cable having different spacing of the grooves.  
         [0067]     The upper and lower insulator layers having conductors arranged in between and spaced corresponding to the spacing of the protrusions  74  of the rotary anvil  70  are fed between the rotary anvil  70  and the rotary horn  60  where bonding of the assembly will occur. The height of the gap  68  between the protrusions  74  and the weld surface  65  is slightly less than the combined height of the two layers of the insulator. Therefore, upon insertion of the upper and lower insulator layers between the weld surface  65  of the rotary horn and the rotary anvil  70 , the insulator layers are compressed between the protrusions  74  and the weld surface  65 . The conductors  40  of the flat cable  10  are spaced correspondingly to the grooves  72 . The conductors  40  fill the space in each groove  72  above the weld surface  65 . The grooves  72  have a predetermined depth in order to avoid the welding of the conductors to the upper and lower insulator layers  20 ,  30 . As the depth of the grooves  72  increases, the amount of tension placed on the lower layer  30  of the flat cable against the weld surface  65  is reduced so that welding does not occur between the conductor and the insulator layers  20 ,  30 . In a preferred embodiment, the grooves  72  have a depth of 0.004 inches.  
         [0068]     In one embodiment, the insulator layers  20 ,  30  and conductors  40  are fed through the gap  68  at a speed of approximately 4 inches per second. The vibrating rotary horn  60  creates a frictional heat at the weld surface  65 . Bonding occurs at the points where the protrusions  74  compress the insulator layers against the active weld surface  65 . The compressive force between the protrusion  74  and the weld surface  65  cause the bonding between the upper and lower insulator layers to occur only at this interface. The protrusions  74  also provide for the shape of upper insulation layer  20  of the flat cable  10 . The grooves  72  form the raised area  25  of the flat cable  10  and the protrusions  74  form the depressed seams  50 . Further the weld surface  65  of the rotary horn  60  includes a pattern which is burned into the lower layer  30  of the insulator. In one embodiment, the pattern on the weld surface  65  is 90° knurl.  
         [0069]     It can thus be understood that there is no bond between the upper and lower insulators at the groove area  72  in which the conductor is located. Therefore, upon the process of exposing the conductors in order to provide for attachment of the flat cable  10  to a component, the conductors  40  may be easily exposed because there is no insulator material adhered to the conductors  40 . Further, it can be understood that the present invention overcomes the prior art in that there is no adhesive bonded to the conductors in that the bonding of the present invention only occurs at the predetermined areas where the protrusions  74  are located.  
         [0070]     Turning to  FIG. 4 , the overall method of assembly of the flat cable  10  may be understood. The operation starts on the right side where multiple conductor reels  81  are mounted. In one embodiment, copper is used as conductors and these copper reels are purchased from Torpedo Wire Company (Pittsfield, Pa.). The conductors are pulled off of the conductor reels  81  and fed through the wiping area  82  in order to bring the conductors to the same plane and to clean the metallic conductors and remove any residue which might reduce conductivity. The conductors are then fed through the wire separation module  83 . The conductor wires are then fed through the conductor straightening module  84  which is a series of grooved rollers that align the conductors. The conductors are then aligned in their final orientation by the conductor guide  85 . The conductor guide  85  includes grooves which are spaced corresponding to the grooves  72  of the rotary anvil  70 . Because the present method does not use adhesives and such liquid adhesives are not present on the insulator layers, the conductors remain positioned on the insulator layers according to the conductor guide  85 . Further, the grooves  72  on the rotary anvil  70  also act to maintain the spacing of the conductors  40 . The upper insulator reel  86  and lower insulator reel  87  include tension control means and are fed along with the conductor wires between the rotary horn  60  and the rotary anvil  70 . The rotary anvil  70  includes guides along its edges in order to align the upper and lower insulator materials and the array of conductor wires. In a preferred embodiment, the upper and lower insulator materials are a clear polyester purchased from Plastic Suppliers, Inc. (Chicago Heights, Ill.).  
         [0071]     The rotary horn  60  is controlled by the sonic controller and power supply  88 . In one embodiment, the power supply is an Amtech 920 MA advanced high frequency constant amplitude power supply providing a 20 KHz at 2,000 watts (Amtech, Inc., Milford, Conn.). In a preferred embodiment, the controller includes a speed control in order to increase and decrease the speed of the assembly process. The power supply would also include an encoder in order to reduce the power when the process is slowed. When the various reels feeding the process need to be exchanged, it is desirable to slow down the process so that the reels may be changed more easily. The encoder and speed control features are coordinated in order to allow for this process. In an alternate embodiment, the controller will include a continuous mode adjustment which allows for the bonding to occur in a continuous mode or a noncontinuous mode and set the intervals at which the bonding will occur. As discussed above, it may be desirable to provide for nonbonded areas at the ends of the desired lengths of the flat cable where it will be separated. The continuous mode feature will provide for the “off” function of the ultrasonic welding for a preprogrammed amount oftime so that a specific distance of the flat cable may have a nonbonded area and the automatic switching of the ultrasonic bonding back to an “on” position in which the continuous bonding is resumed. The controller in a preferred embodiment also includes an amplitude adjustment in order to vary the amplitude in order to control the bonding quality of the rotary horn. In a further alternative method of forming flat cable, insulator layers having windows at predetermined intervals may provide prestripped areas in which the conductors are exposed even during bonding.  
         [0072]     Adjacent the rotary horn  60  is a cooling mechanism in order to cool the weld surface  65  of the horn  60 . Also adjacent the bonding area may be a means of testing the presence and quality of the bond at the seams  50 . In a preferred embodiment, a vision system may be used to test the seams  50 . As the polyester used as insulators in the preferred embodiment is clear and the rotary horn includes a pattern, the bonded seams are not clear. Thus, a vision system may be programmed to test the clarity of the patterned bonded seams  50  of the successfully welded flat cable  10 . If the cable is not bonded, the seams will remain clear and light will pass through the seam  50  without distortion and the bond testing means may be programmed to shut down the assembly process. Such a system may also be programmed to test and record the bonded and nonbonded areas as discussed above in an alternate embodiment.  
         [0073]     The bonded flat cable is then pulled through cable slitter  89  in order to split the full widths of the cable into the desired widths of the subgroups of usable flat cable. As discussed above, in a preferred embodiment, the flat ribbon cable is bonded in three inch wide segments and then separated into six, half inch wide cables having six conductors each. The individually spliced flat cables then move through puller rollers  90 . The puller rollers  90  pull the insulator layers and the conductor wires through the entire assembly process. Finally, the individual flat cables are received by take-up reels  91 . The reels with the flat ribbon cable may then be transported to the specific areas where the flat ribbon cable  10  is to be used and the flat ribbon cable  10  would be cut to the desired lengths and have the ends processed in order to expose the conductors for attachment to a component such as a clockspring. In an alternate embodiment, the assembly process may have incorporated into it the cutting of the flat cable to the desired length and the process for exposing the conductors.  
         [0074]     The stripping process may include the insertion of the end of the flat cable between a rotary grinding machine in order grind off the upper and lower insulator layers to leave the conductors exposed. The excess area beyond the exposed conductors may then be trimmed so that bare exposed conductors protrude from the end of the flat cable so that they may be mounted to a component such as an electrical connector and soldered thereto. In an alternate method of stripping the cable ends, a plurality of spaced, adjacent knife blades or punches may penetrate the insulator layers and pull the insulator layer from between and off of the conductors. The present invention provides for the flat cable having the conductors mounted between the insulator layers but not bonded to the insulator layers which provides for an easier stripping process. Because the conductors are not bonded to the insulator layers, the layers of insulation may more easily be stripped and removed from the surface of the conductors. Therefore, after the stripping process, the flat cable is left having protruding conductors without any adhesive residue. Further, in a preferred embodiment, the stripped conductors do not have any insulator residue either. Thus, it can be understood that the present invention provides for a flat cable having exposed conductors which do not have any residue which may inhibit the conductivity of the conductors and provide for a clean surface for the attachment of the conductors to a metallic surface and to allow for a successful soldering process where desired.  
         [0075]     Furthermore, since the flat cable  10  does not use an adhesive to bond the upper layer  20  to the lower layer  30 , the flat cable  10  is lighter in weight than is a flat cable made using adhesives to bond the insulating layers and conductors together. Testing has shown that when a flat cable having seven conductors, each conductor having a cross-section of 0.007 inches by 0.040 inches, was made having insulating layers of polyester each 0.0003 inches thick. The resulting flat cable weighed 43.5 grams for a ten foot length and the a flat cable made with the same insulating materials and conductors and using an adhesive weighed 48.9 grams for a ten foot length. Thus, the sonically welded flat cable weighed 5.4 grams less for a ten foot length as compared to the flat cable made using adhesive material. Therefore, for a seven conductor flat cable having polyester insulating layers the flat cable has a per unit length linear density of 4.35 grams/foot. The lower weight of the flat cable  10  generally tends to increase the natural frequency of the flat cable  10 . Thus, when the flat cable  10  is installed in a device such as a clockspring, the flat cable  10  is not as susceptible to low frequency vibrational energy often experienced in clocksprings. Therefore, the device which uses the flat cable  10  will tend to be more quiet than a device which does not use flat cable  10 .  
         [0076]      FIG. 5  is an alternate embodiment of the present invention showing the flat electrical cable  10  after the end portion has been stripped to expose the conductors  40 . The flat cable  10  shown in  FIG. 1  discloses the cable  10  in its condition after the bonding procedure discussed above. The cable  10  after the bonding procedure has the conductors enclosed within the upper and lower insulator layers  20 ,  30 . In order to use the flat cable  10  and enable it to be attached to a component, the conductors  40  must be exposed. As discussed above, the conductors may be exposed by stripping the cable to remove the upper and lower insulator layers at an end portion of the cable. As discussed above, procedures such as grinding or cutting the insulator layers with a knife may be used, in addition to the above procedure providing for nonbonded areas.  FIG. 5  shows the flat cable  10  after a stripping procedure has been applied to the cable having the array of conductors  40  exposed at the end portion. The conductors  40  protrude from between the upper and lower layers  20 ,  30  of the insulator and are surrounded on the upper side of the conductor  40  by the rib  25  of the upper layer  20  and having seams  50  on each side of the conductor  40 . According to the advantages disclosed in the above invention, the conductors  40  do not have any adhesive residue thereon. After stripping of the end of the cable  10 , no further procedure such as a cleaning of the conductors is necessary. Due to the bonding method discussed above, without use of adhesives, the conductors are clean and do not have residue which inhibits the conductivity of the metallic material. Following the stripping procedure and the exposure of the conductors  40  as shown in  FIG. 5 , the flat cable may then be attached to a component by soldering the array of conductors to a connector or inserting the conductors into an electrical connector. Thus, it may be understood according to the above description that the present invention provides for a cable  10  which may be manufactured quickly and easily and provide for a cost savings as well as providing for a finished cable which may be more easily stripped and attached to a component. As an example, the component may be an electrical connector mounted to a housing of a clockspring.  
         [0077]     In another embodiment, a perspective view of a preferred knurled flat cable  100  is shown in  FIG. 7 . The knurled flat cable  100  of  FIG. 7  is similar to the flat cable  10  of the embodiment discussed above, the differences between the two flat cables are discussed below. The upper layer  120  is bonded to the lower layer  130  preferably by ultrasonic welding using the plunging mode. The plunging direction  167  is shown in  FIG. 6 .  FIG. 6  is a view of the horn  65  and anvil  70  assembly of  FIG. 2  where the rotary horn  65  operates in the plunge mode and the anvil is a modular rotary anvil  70   a . The modular rotary anvil  70   a  is used to produce the knurled flat cable  100 , where the modular rotary anvil  70   a  has knurled protrusion  74   a , smooth broad protrusions  75 , and smooth broad edge protrusions  75   a . The knurled protrusions  74   a  form the knurled surface texture pattern on the knurled seams  150  of the knurled flat cable  100 . The smooth broad protrusions  75  and  75   a  form the smooth continuous edge seams  115 . The grooves  72  of the modular rotary anvil  70   a  form the raised surfaces or ribs  125 . Conductors  140  comprise an intermediate layer between the upper layer  120  and the lower layer  130 . An optical fiber  141  having at least one buffer coating is also shown in  FIG. 7  in place of one of the conductors  140 , as another embodiment of the invention. However, all of the conductors  140  could be replaced with fiber optic cables  141 .  
         [0078]     Experimental testing has shown that use of the plunge mode provides the most durable manufacturing method. Use of flat cable has shown that when seams between adjacent conductors have a knurled surface texture pattern  150  and the continuous edge seams  115  have a smooth continuous surface texture pattern such a flat cable is quiet in operation and provides for low torque when installed in a clockspring. The knurled center seams provide a low amount of surface area contact when the tape contacts itself, thus reducing friction and hence torque, when in a clockspring the flat cable is coiled up around itself. The smooth edge seam of the flat cable provides a smooth contacting surface between the flat cable and the interior surfaces of the clockspring housing and parts therein such as damping material. Other embodiments were tested. No other form of flat cable performed as well. One test was conducted on a flat cable where all of the seams were knurled. Another test was conducted on a flat cable where all of the seams were smooth and continuous. Further testing compared flat cable bonded by the shear mode to flat cable bonded by the plunge mode of ultrasonic welding. Such durability is required when the knurled flat cable  100  is used in a clockspring. Flat cable used in a clockspring is coiled and held within the clockspring housing where the flat cable is repeatedly partially uncoiled and recoiled. However, since the flat cable is coiled, the flat cable must be flexible. A smooth edge seam is determined to be smooth relative to the knurled seams located between adjacent conductors. As such, the smooth edge seams have a surface roughness which is less than the surface roughness of the knurled seams located between adjacent conductors. In a preferred embodiment the knurled flat cable  100  is made with the modular rotary anvil  70   a  as shown in  FIG. 6 . The anvil  70   a  is called a modular rotary anvil since it is formed of discrete modular segments, sections, or inserts.  FIGS. 8A and 9A  display side views of two different forms of the modular rotary anvil.  FIG. 8A  shows an assembly of knurled inserts  160 , broad protrusion inserts  162 , a large bracket insert  164 , a small bracket insert  166 , a first end segment  168 , and a second end segment  170  which form the modular rotary anvil  70   a .  FIGS. 6 and 8 B shows the knurled insert  160  having recesses  72  and knurled protrusions  74   a .  FIGS. 10A through 13B  display some of the various individual inserts.  
         [0079]      FIG. 10A  is a side view of the large bracket insert  164 , and  FIG. 10B  is a front view of the large bracket insert  164 .  FIG. 11A  is a side view of the small bracket insert  166 , and  FIG. 11B  is a front view of the small bracket insert.  FIG. 12A  is a side view of the knurled insert  160 , and  FIG. 12B  is a front view of the knurled insert  160 .  FIG. 8B  shows details of the knurled insert  160 .  FIG. 13A  is a side view of the broad protrusion insert  162 , and  FIG. 13B  is a front view of the broad protrusion insert  162 . The assembly of inserts and segments are held together with socket head cap screws. The socket head cap screws are countersunk into one of the large bracket insert  164  and the small bracket insert  166  and the socket head cap screws are threaded into one of the other of the large bracket insert  164  and the small bracket insert  166 . The first end segment  168  is attached to the small bracket insert  166  with socket head cap screws and the second end segment  170  is attached to the large bracket insert  164  with socket head cap screws. Alternatively, the assembly of inserts and segments are held together on a common shaft and secured with a nut and lock washer. The modular rotary anvil  70   a  can then be mounted on the ultrasonic welding machine as would any conventional rotary anvil.  
         [0080]     The modular rotary anvil  70   a  can be used to make flat cable of many different dimensions and configurations. As described above, in regard to the flat cable  10 , a different rotary anvil  70  was required if different seam width dimensions were necessary. Thus, a manufacturer of flat cable would be required to maintain a large inventory of rotary anvils. Such an inventory is expensive to produce and maintain. Furthermore, such an inventory relates directly to the cost of the flat cable produced. A further drawback to the rotary anvil concept is that the lag time between conception of a unique rotary anvil design and the finished manufactured rotary anvil is a relatively long period of time.  
         [0081]     Applicant&#39;s modular rotary anvil  70   a  eliminates the need for a large inventory of rotary anvils. Instead, now, a manufacturer need only keep an inventory of different modular segments, sections, or inserts. The inserts can be built up or assembled in different ways to make a modular rotary anvil, where the modular rotary anvil produces a variety of flat cable designs. Such a concept supports flexible manufacturing needs, where the manufacture of different flat cable can be supported in a short amount of time. Thus, meeting the needs of the market. Furthermore, the invention of the modular rotary anvil results in flat cable which costs less to produce as compared to the prior art.  
         [0082]      FIG. 9A  is a side view of another modular rotary anvil  70   b  which has cutting inserts  172  interspersed between knurled inserts  160 .  FIG. 9B  is a detailed view of a portion of  FIG. 9A  showing the cutting inserts  172 . The cutting insert  172  attach to the modular rotary anvil  70   b  the same way as did the broad protrusion insert  162  of the modular rotary anvil  70   a . In the embodiments discussed above the plurality of flat cables produced by a single rotary anvil were separated from each other by the cable splitter  89  shown in  FIG. 4 . The cutting insert  172  eliminates the need for the cable splitter  89 ; thus, reducing the number of steps need to produce the flat cable. The cutting insert  172  achieves this result by being able to ultrasonically bond the upper and lower layers together to form a seam, while substantially simultaneously the cutting insert  172  cuts the flat cable of the just bonded seam. Other portions of the modular rotary anvil  70   b  are the same as the modular rotary anvil  70   a  described above.  
         [0083]     In still yet another embodiment of the invention, a perspective view of a preferred edge seam semi-knurled flat cable  200  is shown in  FIG. 16 . The edge seam semi-knurled flat cable  200  of  FIG. 16  is similar to the knurled flat cable  100  of the embodiment discussed above and shown in  FIG. 7 , the differences between the two flat cables are discussed below. The upper layer  120  is bonded to the lower layer  130  preferably by ultrasonic welding using the plunging mode. The operation of the plunge mode is similar to that described in regard to the flat cable  100 . However, in this embodiment, the modular rotary anvil would not have a smooth broad edge protrusion  75   a  forming the smooth continuous edge seam  115 . Instead, the protrusion of the rotary modular anvil (not shown) has half of its width knurled and the other half smooth. Such a protrusion of the rotary modular anvil forms a semi-knurled edge seam  215 . The semi-knurled edge seam  215  includes a first zone  217  adjacent one of the conductors which is knurled and a second zone  216  which is smooth, as shown in  FIG. 16 .  
         [0084]     The semi-knurled edge seam flat cable  200  has the advantage that when used in a clockspring, it is still quiet, due to the use of the smooth edge portion of the edge seam. However, this embodiment solves a problem by including the first zone  217  of the edge seam  215  which is knurled. The knurled seam requires less energy than the smooth continuous seam. Since the edge seam  215  includes a knurled zone, the edge seam  215  requires less energy to bond the edge seam  215 . The energy savings is then directed towards the seams located between the conductors, so as to make those seams  150  more strong. Otherwise, to ensure a proper bond between the upper layer  120  and the lower layer  130  at the location of the seams positioned between the conductors, the speed at which the flat cable exits the manufacturing machinery must be decreased. So the semiknurled edge seam  215  enables the flat cable  200  to exit the manufacturing machinery at a high rate of speed while still maintaining its structural integrity.  
         [0085]      FIG. 17  is an expanded view of an alternative knurl or surface texture pattern as can be produced on flat cables  100  or  200 . The raised surfaces or ribs  125  are smooth and the seam region  220 , which corresponds to seams  150 , can have a surface texture formed of a row of repeating parallel lines or linear segments, where the lines or linear segments are substantially perpendicular to a length dimension of the flat cable. Such a surface texture is easy to grasp, forces a strong bond, and is a relatively easy pattern to impart on the modular rotary anvil.  
         [0086]      FIGS. 18-23  show end views of alternative conductors or conductor groups. Alternative conductor configurations solve various problems experienced while using flat cable. A single conductor  140  is inexpensive to manufacture and assemble. Depending on the radius of curvature that the flat cable experiences, the conductor  140  may experience large bending stresses. As such, it is better to reduce the stresses by making the conductor smaller. Furthermore, a smaller conductor requires less force to bend the flat cable. Additionally, alternative conductor combinations make it possible to carry higher current loads for a short amount of time.  FIG. 18  is an end view of a single conductor  140  having a width, w, and a thickness, t, as shown in the previous embodiments.  FIG. 24 , is an exploded, perspective view of the single flat conductor  140  assembled with an upper insulation layer  120  and a lower insulation layer  130 . The upper and lower insulation layers  120 ,  130  are shown separated from each other for reasons of clarity. The single conductor shown is just one of many that would populate the flat ribbon cable.  
         [0087]      FIG. 19  is an end view of a dual or tandem conductor group  240 , where each of the individual conductors  241 ,  242  are substantially identical to each other. In this embodiment, each of the conductors  242 ,  241  has a thickness, t, which is similar to that of the single conductor  140 , and a width, w/2, which is substantially one-half of the width of the single conductor  140 . Thus, the dual or tandem conductor group  240  fits within the pre-existing space of the single flat conductor  140 . Therefore, the shape of the rotary modular anvil does not change.  FIG. 25  is an exploded, perspective view of the dual or tandem conductor group  240  assembled with an upper insulation layer  120  and a lower insulation layer  130 . The dual or tandem conductor group shown is just one of many that would populate the flat ribbon cable.  
         [0088]      FIG. 20  is an end view of a dual stacked conductor group  243 , where each of the individual conductors  244 ,  245  are substantially identical to each other. In this embodiment, each of the conductors  244 ,  245  has a thickness, t/2, which is one-half of the thickness of the single conductor  140 , and has a width, w, which is similar to that of the single conductor  140 . Thus, the dual stacked conductor group  243  fits within the pre-existing space of the single flat conductor  140 . Therefore, the shape of the rotary modular anvil does not change.  FIG. 27  is an exploded, perspective view of the dual stacked conductor group  243  assembled with an upper insulation layer  120  and a lower insulation layer  130 . The dual stacked conductor group shown is just one of many that would populate the flat ribbon cable.  
         [0089]      FIG. 21  is an end view of a triple stacked conductor group  246 , where each of the individual conductors  247 ,  248 ,  249  are substantially identical to each other. In this embodiment, each individual conductor  247 ,  248 ,  249  has a thickness, t 13 , which is substantially one-third of the thickness of the original conductor  140 , and a width, w, which is similar to that of the original conductor  140 . Thus, the triple stacked conductor group  246  fits within the pre-existing space of the single flat conductor  140 . Therefore, the shape of the rotary modular anvil does not change.  FIG. 26  is an exploded, perspective view of the triple stacked conductor group  246  assembled with an upper insulation layer  120  and a lower insulation layer  130 . The triple stacked conductor group shown is just one of many that would populate the flat ribbon cable.  
         [0090]      FIG. 22  is an end view of a wire rope conductor group  250 .  FIG. 23  is an end view of a wire rope conductor  250  after the wire rope conductor  150  has been compressed. Seven individual wires are shown. Each wire is approximately 24 gauge. The compressed wire rope conductor  250  has a thickness, t, similar to that of the original conductor  140 , and a width, w, similar to that of the original conductor  140 . Thus, the wire rope conductor group  250  fits within the pre-existing space of the single flat conductor  140 . Therefore, the shape of the rotary modular anvil does not change.  FIG. 28  is an exploded, perspective view of the compressed wire rope conductor group  250  assembled with an upper insulation layer  120  and a lower insulation layer  130 . The compressed wire rope conductor group shown is just one of many that would populate the flat ribbon cable.  
         [0091]     Furthermore, a single flat ribbon cable can include conductors of various forms. As an example, a flat cable can have seven conductors. The first conductor can be a single flat conductor  140 , the second conductor can be a dual or tandem conductor  240 , the third conductor can be a dual stacked conductor  243 , the fourth conductor can be a triple stack conductor  246 , the fifth conductor can be a compressed wire rope conductor  250 , the sixth conductor can be an optical fiber  141 , and the seventh conductor can be a single flat conductor  140 . Other combinations of conductors are possible and can be suited to the industrial requirements of the use of the device.  
         [0092]     Other embodiments are also envisioned such as a clockspring containing flat cable, where the clockspring connects crash sensors to an airbag located in a harness-type seat belt. Such a clockspring would take-up the slack of the seat belt when the seat belt spooled and un-spooled. Non-automotive applications are also envisioned.  
         [0093]     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the appended claims.