Abstract:
Disclosed herein is a method and apparatus for splicing flexible circuit boards, particularly those having one or more flexible strip extensions with conductor runs. The splice clamp of the present invention has two hinged plates that clamp over unconnected ends of two flexible circuit board segments. The splice clamp includes alignment guides for aligning the segments in the clamp so that one or more jumpers contact and provide an electrical bridge between the conductors of the segments when the plates are clamped together. The jumpers contact conductive pads of larger size than the conductor runs to ensure electrical coupling between the flexible circuit board segments. The jumpers may have pointed tips that cut through insulation. The clamp includes flexible clasps on one plate that engage with catch surfaces on the other plate to lock the flexible circuit board segments spliced together.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit to U.S. provisional application serial No. 60/130,860, filed Apr. 22, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to printed circuit boards and in particular to a method and apparatus for splicing segments of flexible circuit boards when servicing or replacing electronic components in automobiles. 
     Automobiles include many complex electrical assemblies for use in sophisticated engine control systems including a variety of sensors for detecting such conditions as engine temperature, throttle position, engine speed and air intake. These control systems typically include microprocessors to process the signals from these sensors and produce control signals for operating engine components such as throttle valves, ignition coils and fuel injectors. 
     Ordinarily, the electronics in such control systems are interconnected via a printed circuit board. Printed circuit boards are used because they provide reliable connection between the electronic components. Typical circuit boards have a rigid substrate on which the circuit is printed. Due to their rigid construction, the electronics on the circuit board must be connected to sensors and vehicle components by a wiring harness. Wiring harnesses are costly and are prone to failure in the connection of the harness to the circuit board but also in the connection to connector pins. Moreover, wiring harnesses clutter the engine compartment making it more difficult to assemble and service the engine. 
     One method of providing reliable connections without using bulky and expensive wiring harnesses is to use flexible circuit boards typically made of a conductive layer laminated to a flexible insulating substrate. Such flexible circuit boards can be fabricated to include finger-like extensions that are sufficiently flexible to follow a curved path between the control circuitry and the sensor or vehicle component. 
     Such flexible circuit boards provide the advantage of obviating wire harnesses. Moreover, using such circuit boards can also eliminate pin connectors between the circuit board and the sensors or vehicle components, which can decrease cost as well as connection related problems. However, like wires, the finger-like extensions can be damaged from flexure and abrasion occurring during normal use of the automobile. And, without connectors between the circuit board and the sensors or components, it is ordinarily more difficult and expensive to service or replace components of the electrical assembly. This is because the remote components are directly connected to a main circuit board by the integral extensions. Thus, replacing one sensor or vehicle component ordinarily requires that the entire assembly to which it is connected be replaced. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a connector for splicing uniquely configured flexible circuit boards when servicing electrical assemblies. In an automobile environment, the present invention permits the use of flexible circuit boards having integral finger-like extensions running directly to vehicle components without using connectors such that a single electronic component can be replaced without replacing the entire assembly. 
     Specifically, the present invention provides a clamp for splicing flexible circuit boards each having a flexible substrate supporting an electrically conductive circuit with at least one electrically conductive contact pad proximate alignment openings. The clamp has a first plate with a lateral channel sized to receive the circuit boards as well as alignment posts projecting from within the channel. The clamp also has a second plate hinged to the first plate. The second plate has alignment post recesses and one or more lateral metallic jumpers with conductive ends extending toward the first plate. In use, the circuit boards are aligned end to end in the first plate and the plates are clamped together. This causes the jumper to contact the contact pads of each circuit board and couple them electrically. 
     One aspect of the present invention is a kit for use with an automobile electronic assembly. The electronic assembly has a first electronic component mounted to a flexible circuit board with a finger-like extension. The extension is made of a flexible substrate supporting runs of conductors having electrically conductive contact pads. The kit includes a second electronic component having electrical terminals, a replacement extension and a splice connector. The replacement extension is made of a flexible substrate supporting runs of conductors having electrically conductive contact pads at one end. The replacement extension is electrically coupled to the electrical terminals of the second component at another end. The splice connector has conductive jumpers that bridge the contact pads of the extension to the contact pads of the replacement extension so that the first electronic component is electrically coupled to the second electronic component. 
     Another aspect of the invention is a method for servicing electronic assemblies in automobiles having a first electronic component with a flexible circuit board and a flexible extension supporting conductor runs that couple the first electronic component to a second electronic component. The flexible circuit extension is cut cross-wise so that the extension is in two segments. A first segment is connected to the first electronic component and a second segment is connected to the second electronic component. Then, the first electronic component and the first extension segment are removed and a replacement component is installed. The free ends of the second extension segment and a replacement extension segment are brought together so that the conductor runs of the second extension segment are aligned with conductor runs of the replacement extension segment. A splice connector is then clamped over the free ends so that metallic jumpers bridge the conductor runs of the extension segments. 
     Still another aspect of the invention includes a flexible circuit board having a conductor circuit supported by a flexible substrate. Finger-like extensions of the board support runs of conductors connected at one end to the conductor circuit of the board body. The extensions have a pre-defined splice region wherein the splice region is defined by laterally aligned conductive contact pads coupled to the conductor runs of increased width than the conductor runs. 
     Thus, the present invention provides a quick and easy method and apparatus for servicing electrical assemblies connected via a flexible circuit board. The present invention also obviates separate pin connectors between the components in the assembly, allowing the components to be directly connected to the flexible board. Despite this, only the failed or damaged components can be replaced without replacing the entire assembly. Thus, the present invention reduces initial material and assembly costs by obviating connectors and reduces replacement costs by facilitating replacement of only the failed or damaged component(s). 
    
    
     The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of an engine control unit (ECU) mounted atop an engine air intake manifold having a flexible circuit board with extensions leading from the ECU to ignition coils; 
     FIG. 1A is an enlarged view of a splice region of a flexible circuit board extension in FIG. 1; 
     FIG. 2 is a front perspective view of a splice clamp of the present invention in an open position; 
     FIG. 3 is a perspective view the splice clamp of FIG. 2 having flexible circuit board sections aligned for splicing; 
     FIG. 4 is a perspective view similar to FIG. 3, however, with the clamp closed so that the flexible circuit board sections are electrically spliced together; 
     FIG. 5A is an end cross-sectional view taken along line  5 A— 5 A of FIG. 4 showing a jumper connection; 
     FIG. 5B is a side cross-sectional view taken along line  5 B— 5 B of FIG. 4; 
     FIG. 5C is an end cross-sectional view taken along line  5 C— 5 C of FIG. 4; 
     FIG. 6 is an end cross-sectional view of an alternate embodiment of the splice clamp; 
     FIG. 7 is a side cross-sectional view of another embodiment of the splice clamp; 
     FIG. 8A is a perspective view of an another embodiment of the present invention with two separate plates, one of which is integrally mounted to a support for an electronic component; 
     FIG. 8B is a perspective view of the embodiment of FIG. 8A, shown with the extension and replacement extension in the lower plate; and 
     FIG. 8C is a perspective view of the embodiment of FIG. 8A, shown with the upper plate connected to the lower plate so as to splice the extension to replacement extension together. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows an engine control unit (ECU) housing  10  mounted atop an air intake manifold  12  of an eight cylinder internal combustion engine  14  (shown in phantom) having individual ignition coils  16  and fuel injectors (not shown) mounted at each cylinder. The ECU housing  10  includes a protective cover  18 , through which extends a throttle body elbow  19 , that can be removed to access to the ECU circuitry within the housing  10 . The ECU circuitry  20  is mounted on a panel portion  22  of a flexible printed circuit board  24 . Referring briefly to FIG. 5A, the flexible circuit board  24  is comprised of a flexible substrate  26  supporting an electrically conductive layer  28  which is coated with a thin insulating layer  30 . Preferably, the flexible circuit board  24  is an etched-tri-metal composite circuit board having an aluminum layer separating two layers of copper, however for clarity, the figures show only one conductive layer. Also, it should be noted that the present invention can be used with flexible circuit board of any composition and suitable configuration. 
     Referring again to FIG. 1, the flexible circuit board  24  includes eight fingerlike extensions  32  electrically connecting the ECU circuitry  20  to each ignition coil  16  and fuel injector. The extensions  32  are integral with and of the same flexible circuit board as the panel portion  22  so that they can follow the profile of the air intake manifold  12 . Referring to FIG. 1A momentarily, the extensions  32  include four conductor runs  33  (two for each coil and fuel injector) preferably aligned in parallel running the length of the extensions  32 . Each conductor run includes a conductive contact pad  35  of increased area. The contact pads  35  are laterally aligned at a splice region  37  near the top of each extension  32 . A pair of alignment openings  39  are disposed in the splice region  37  at the sides of the contact pads  35 . 
     Returning to FIG. 1, preferably, the extensions  32  are hardwired directly to terminals (not shown) of the ignition coils  16  and fuel injectors. In this way, no separate connectors are needed to electrically couple the ECU circuitry  20  to the ignition coils  16  and injectors. Ordinarily, without separate connectors, if the ECU circuitry  20  or a single extension  32  or ignition coil  16  needed replacement, then all connected components would have to be replaced, despite operating properly. However, using a splice clamp  34  of the present invention (see FIG.  2 ), one or more failed extensions  32  or coils  16  can be serviced or replaced individually. Moreover, using such a splice clamp  34  allows replacement of the ECU circuitry  20  without replacing the coils  16 . Thus, the present invention reduces initial material and assembly costs by obviating connectors and reduces replacement costs by facilitating replacement of only the failed or damaged component. While obviating connectors is a primary advantage of the present invention, it should be noted that pin connectors (not shown) could be used at the ends of the extensions  32 , if desired, so that the ignition coils  16  and injectors can be unplugged from the ECU circuitry  20 . 
     For example, the splice clamp  34  can be used to splice an extension  32  to a replacement extension  36  attached to a replacement coil  17 . The extension replacement  36  has the same width and splice region configuration (i.e., quantity and spacing of conductors, contact pads, and alignment openings), as described above for the extensions  32 . 
     Specifically, the splice clamp  34  includes upper  38  and lower  40  plates joined together at a back end  42  by a living hinge  44  to form a clam-shell structure injection molded of a suitable plastic resin. Referring to momentarily to FIGS. 5A-5C, a rigid stiffener  43  (shown in phantom in the lower plate  40 ) can be insert-molded into one or both plates to provide additional structural support. In any event, the lower plate  40  has a lateral recess  46  slightly larger than the width and slightly deeper than the thickness of the extensions  32 . The recess  46  has a planar bottom surface  48  upon which the spliced extensions rest and four alignment posts  50  projection up therefrom. The alignment posts  50  are longitudinally spaced to mate with the alignment openings  39  in the extensions and replacement extensions  36  (see FIG.  1 A). The alignment posts  50  are laterally spaced so that the ends to be spliced nearly abut but do not overlap the replacement extension  36  (see FIG.  3 ). 
     The upper plate  38  includes a flat top surface  54  having recesses  56  registered with the alignment posts  50  and sized to contain the alignment posts  50  when the splice clamp  34  is closed together. Molded integrally with the top plate  38  are inverted U-shaped metallic jumpers  58 , preferably a copper alloy such as phosphor bronze, having pointed tips  60  projecting downward through the top surface  54 . The tips  60  are pointed to cut through the insulating coating  30  over the conductive layer  28  (see FIG.  5 A). The jumpers  58  are sized and spaced according to the conductor runs  33  of the extensions  32  being spliced (see FIG.  1 A). It should be noted that the figures show four such jumpers  58 , however, the number of jumpers  58  will depend upon the number of conductor runs contained in the extensions being spliced. Moreover, the figures show the jumpers  58  extending from the top surface  54  a uniform distance, however, this could be varied so that the jumpers  58  make contact with conductors lying in different planes, as in an etched composite circuit board. 
     Referring to FIGS.  2  and  5 C,the lower plate  40  has tapered clasps  52  projecting upward at its corners. The top plate  38  also includes notched comers  62  providing catch surfaces  64  for mating with the clasps  52  of the bottom plate  40 . When the plates  38  and  40  are brought together, the clasps  52  are deflected outward by the upper plate  38  until they engage the catch surfaces  64  of the notched corners  62 . In this way, the plates  38  and  40  are locked together. The clasps  52  can be pulled outward to unlock the splice clamp  34 . 
     Referring again to FIG. 1, coils  16 , extensions  32  or the ECU circuitry  20  are replaced by cutting the necessary extension(s)  32  at the splice region  37  slightly below the contact pads  35 . Any suitable shear, scissors or dedicated cutting tool can be used. Moreover, the splice clamp  34  could include an integral blade (not shown) suitably disposed at the upper  38  or lower  40  plate so that no additional tool is needed to cut and connect the replacement extension  36  to the extension  32 . The failed or damaged component is then removed and substituted by a replacement component, such as replacement coil  17 , having the replacement extension  36 . As mentioned, at its free end, the replacement extension  36  includes a splice region having the same width, conductor configuration and alignment openings as the extensions  32 . 
     Referring to FIG. 3, the cut extension  32  and the replacement extension  36  are each aligned in the splice clamp  34  so that the alignment openings  39  fit over the alignment posts  50 . A bead sealant  63 , preferably silicon based, is laid over a seam  65  to encapsulate the conductor runs  33  and prevent possible corrosion along the seam  65 . Then, the recesses  56  of the upper plate  38  are aligned with the alignment posts  50  and the upper  38  and lower  40  plates are brought together so that the seam  65  is covered. Applying a clamping force, such as by squeezing the splice clamp  34  by hand, forces the jumper tips  60  through the insulation layer  30  to contact the contact pads  35 , as shown in FIGS. 5A-5B. The clasps  52  of the bottom plate to engage the catches  64  of the top plate  38  to lock the jumpers  58  in contact with the contact pads  35 . In this way, the electrical connection to the replacement component is established and maintained. 
     An alternate embodiment of the splice clamp of the present invention is shown in FIG.  6 . In this embodiment, the splice clamp  100  includes a planar body  102  supporting at a bottom side  104  a set of inverted U-shaped jumpers  106  aligned in parallel. Two pivot legs  108  are attached at each end  110  of the planar body  102  at pivot posts  112 . The pivot legs  108  have feet  114  angling inward toward each other. This alternate clamp  100  is used by fitting the pivot legs  108  into two alignment slots  116  at the splice region of each extension  32 A and replacement extension  36 A, so that the planar body  102  covers the seam. By pulling the top ends  118  of the pivot legs  108  outward, the pivot legs  108  pivot about the pivot posts  112  so the feet  114  press upwardly against the bottom of each extension  32 A and replacement extension  36 A. In this way, the splice clamp  100  forces the jumpers  106  in contact with contact pads  120  to electrically couple the extension  32 A to the replacement extension  36 A. The legs  108  then can be suitably held in a locked position, such as by integral bosses  122 . 
     Referring now to FIG. 7, a second alternate embodiment of the splice clamp of the present invention is shown. In this embodiment, the splice clamp  200  includes an inverted U-shaped body  202  having legs  204  with feet  206  defining catch surfaces. The body  202  has downwardly extending inverted U-shaped jumpers  208  (three shown) and a support backing  210  hingedly attached at one end to an upper support  211 . This embodiment is used by inserting the legs  204  into alignment openings  212  in the extension  32 B and replacement extension  36 B so that the feet  206  catch bottom surfaces  214 . The support backing  210  is than pressed toward the body  202  so that the jumpers  208  contact the contact pads of the extension  32 B and replacement extension  36 B. 
     In yet another alternate embodiment shown in FIGS. 8A-8C, the splice clamp  300  is similar to the preferred embodiment, however, the upper  302  and lower  304  plates are separate, rather than joined by a hinge. And, the upper  302  or  304  lower plate is insert molded or otherwise made integral with a support for one of the electronic components in a location proximate the extension  32 C. FIG. 8A shows the lower plate  304  molded into the air intake manifold  12  beneath the extension  32 C proximate its splice region  37  (as shown in FIG.  1 A). Referring to FIGS. 8B and 8C, the splice ends of the extension  32 C and replacement extension  36 C are aligned in a recess  307  in the lower plate  304  so that their conductor runs  308  and contact pads  310  are aligned (by mating alignment posts  312  in alignment openings  314 ). The upper plate  302  (having jumpers  315 ) is engaged with the lower plate  304  by clasps  316  at the corners. The upper  302  and lower  304  plates are then clamped around the extension  32 C and replacement extension  36 C to electrically couple them together. Although not shown, it should be noted that one of the plates could be integrally joined to a component housing, the extension, the replacement extension and/or any other structure provided the conductor pads of the extension and replacement extension can be aligned and bridged together by the jumpers. 
     While there has been shown and described what are at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention. For example, the spliced ends of the flexible circuit board may also be hermetically sealed in various ways, such as by including sealant or an integral or separate resilient seal at the periphery of the upper and lower plates, or including a separate or integral resilient seal in the upper and/or lower plates which extends along a seam line between the extension and replacement extension. Moreover, the jumpers can be arbitrarily shaped stampings that may cross over each other with dielectric material therebetween. Finally, the splice clamp of the present invention can be used with flexible circuit board of different construction, size and conductor configuration to electrically couple two or more electrical components within an automobile or in any other electrical assembly. For example, in an automobile the splice clamp may be used with position, temperature, pressure and airflow sensors, valve controllers, motors, instrument panel devices and cabin environmental controls. Specifically, such devices include a throttle position sensor, an exhaust gas recirculation valve, temperature and manifold absolute pressure sensors, inlet air temperature sensors and by-pass throttle air valve. 
     Accordingly, reference must be had to the following claims to ascertain the full scope of the invention.