Wire harness and method of manufacturing the same

Abstract: A wire harness includes a flat cable having a trunk portion (12) formed by covering a plurality of parallel electric wires with an insulating coating by integral molding, a plurality of branch portions (13, 14) formed by branching the trunk portion, and a joint device (15) for connecting not less than two electric wires of the plurality of electric wires constituting the trunk portion to electrically short-circuit the branch portions. A wire harness manufacturing method includes the step of tearing an end portion of a trunk portion (12) of a flat cable in accordance with the number of branch portions required, and cutting off unnecessary portions, thereby forming branch portions (13, 14), the trunk portion being formed by covering a plurality of electric wires with an insulating coating by integral molding, the step of mounting a connector on the distal end of each branch portion, and the step of mounting a joint device (15) on the trunk portion to electrically short-circuit not less than two electric wires of the electric wires of the trunk portion.

Description: The present invention relates to a wire harness. For example, a wire harness generally used for a vehicle or the like is constituted by a bundle of a plurality of electric wires which branch off at proper positions to connect a plurality of electric devices with each other. Since such a wire harness has a substantially circular cross-section, it is difficult to decrease the thickness of the wire harness. When, for example, a wire harness is to be installed in a door of a vehicle, the wire harness must be arranged to avoid the space for window members housed in the door. For this reason, the wire harness must be installed over a long distance. In addition, when a large number of electric wires are to be installed, a branching operation is difficult to perform. If the electric wires are to be distinguished from each other by using different colors in consideration of such a situation, a large number of colors are required, resulting in an increase in cost. It is an object of the present invention to provide an improved wire harness which suppress an increase in thickness of the wire harness and allows it to be installed in a narrow space. It is another object of the present invention to provide a wire harness which allows an easy branching operation regardless of the number of electric wires. The invention is as defined in the accompanying claims. According to the present invention there is provided a wire harness comprising: a substantially flat cable including a plurality of parallel electric wires covered with an insulating coating for insulating said wires and for maintaining said wires substantially parallel, said cable including a trunk portion separating into at least first and second branch portions; a connector mounted to electric wires of the trunk portion and mounted on an end portion thereof; and a joint device spaced from said connector and electrically connecting at least two wires, including a first wire extending from said joint device into said first branch portion; and a second wire extending from said joint device into said second branch portion, said joint device thereby short circuiting said first and second branch portions; wherein said first and second wires are electrically disconnected from said connector between said joint device and said connector. A prior art that is of interest is US-A-4065 199 that is concerned with a wire harness comprising a plurality of parallel electric wires having a common insulating coating formed by integral molding and in which the trunk portion of said parallel wires is slit lengthwise to form branch portions that are then folded to settings directed at right-angles to said trunk portion, the folds being secured by adhesive tape, or bonded, or otherwise secured. This prior art is particularly concerned with means whereby the free ends of the branch portions can easily be provided with terminals. Another prior art is GB-A-2 141 593 that is concerned with the prevention of cross talk between signal conductors and discloses a connector wherein a multiple core flat insulated cable is pinched between a connector cover and a connector substrate, said connector having insulation-piercing terminals by means of which, is stated, said insulation-piercing terminals serve to divide the conductors of the flat cable into conductor segments extending in one direction and conductor segments extending in the other direction, and causing different signal contacts of said connector substrate to catch hold of and electrically connect the respective conductor segments at their terminals on the perforation sides, thereby forming different signal lines with said perforations as boundries. EP-A-O 570 893 is concerned with a kit of parts for assembly together about two cables, each cable having therein a plurality of signal wires and drain wires. When said parts are assembled around the two cables the signal wires of one cable are commoned with the signal wires of the other cable; and the drain wires of the two cables are also commoned. EP-A-0 242 113 is a prior art that is concerned with an apparatus and method for making harnesses from flat cable; the apparatus including a cable end slitting mechanism, an eye forming mechanism, a loop forming mechanism and a transfer mechamism. EP-A-0 534 659 is a prior art that is concerned with a method of so shaping a harness that it is easy to arrange the harness in the door of a vehicle. The present invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a plan view showing a wire harness according to the first embodiment of the present invention; FIG. 2 is a plan view of a wire harness according to the second embodiment of the present invention; FIG. 3 is a plan view showing the internal connection of the wire harness in FIG. 2; FIG. 4 is a perspective view showing a flat cable constituting the wire harness in FIG. 2; FIG. 5 is an exploded perspective view showing the arrangement of a joint device; FIG. 6A is a perspective view showing a clamping of a trunk portion by using first and second adhesive tapes; FIG. 6B is a perspective view showing a fixing of each cable by using the first and second adhesive tapes; FIG. 7 is a plan view showing a step in the construction of a wire harness of the present invention; FIG. 8 is a plan view showing a step in the construction of the wire harness of the present invention; FIG. 9 is a plan view showing a step in the construction of the wire harness of the present invention; FIG. 10 is a plan view showing a step in the construction of the wire harness of the present invention; FIG. 11 is a plan view showing a step in the construction of the wire harness of the present invention; FIG. 12 is a plan view showing a step in the construction of the wire harness of the present invention; FIG. 13.is a plan view showing the step in FIG. 8, in detail, in the construction of the wire harness in FIG. 2; FIG. 14 is a plan view showing the step in FIG. 10, in detail, in the construction of the wire harness in FIG. 2; FIG. 15 is a plan view showing a wire harness according to the third embodiment of the present invention; FIG. 16 is a flow chart showing steps of manufacturing a wire harness of the present invention; FIG. 17 is a plan view showing a wire harness according to the fourth embodiment of the present invention; FIGS. 18A to 18C are perspective views showing an example of how a short-circuiting device used for the wire harness in FIG. 17 is mounted; FIG. 19 is a flow chart showing steps of manufacturing the wire harness in FIG. 17; Embodiments of the present invention will be described below. The first embodiment of the present invention will be described first with reference to FIG. 1. Referring to FIG. 1, reference numeral 10 denotes a wire harness of this embodiment. The wire harness 10 comprises a trunk portion 12 constituted by a flat cable formed by covering a plurality of parallel electric wires 11 with an insulating coating by integral molding, branch portions 13 and 14 formed by branching one end portion of the trunk portion 12, and a joint device 15 arranged on the trunk portion 12 to connect two or more electric wires of the electric wires 11 constituting the trunk portion 12 so as to electrically short-circuit the branch portions 13 and 14. A first connector 16 is mounted on an end portion, of the trunk portion 12, located on the opposite side to the branch portions 13 and 14 of the electric wires 11. Second and third connectors 17 and 18 are respectively mounted on the end portions of the branch portions 13 and 14. The joint device 15 connects a wire of the branch portion 13 to a wire in the branch portion 14; and a further wire in the branch portion 13 to a further wire in the branch portion 14 via two short-circuiting metal members 19. As indicated by the broken lines in FIG. 1, the electric wires short-circuited by the short-circuiting metal members 19 are used to electrically connect the branch portions 13 and 14 to each other, and hence are cut in advance so as not to be connected to the first connector 16. According to the wire harness 10, the trunk portion 12 and the branch portions 13 and 14 can be formed from one flat cable. Therefore, in the step of cutting the flat cable and the step of mounting the connectors, the electric wires 11 can be easily positioned with respect to the connectors 16, 17, and 18, resulting in an improvement in manufacturing efficiency. In addition, the cutting step, the connector mounting step, and the like can be easily automated. A wire harness according to the second embodiment of the present invention will be described next with reference to FIGS. 2 to 6. Referring to FIG. 2, reference numeral 20 denotes a wire harness. The wire harness 20 is installed to spread all over the interior of a door D. In addition, one end of the wire harness 20 is arranged in a body B of a vehicle. As shown in FIGS. 2 and 3, similar to the wire harness 10 in FIG. 1, the wire harness 20 comprises first and second trunk portions 22a and 22b constituted by a flat cable formed by integrating a plurality of electric wires 21 into a parallel strip using an insulating coating, first to ninth branch portions 23, 24, 25, 26, 27, 28, 29, 30, and 31 formed by branching one end portion of each of the first and second trunk portions 22a and 22b, a first joint device 32 arranged on the first trunk portion 22a to connect two or more electric wires of the electric wires 21 constituting the first trunk portion 22a so as to electrically short-circuit the branch portions 23 and 24, and a second joint device 33 arranged on the second trunk portion 22b to connect a plurality of electric wires 21 constituting the second trunk portion 22b so as to electrically short-circuit the branch portions 23 and 27. As shown in FIG. 4, each of the first and second trunk portions 22a and 22b is formed by integrating large numbers of electric wires 21a and 21b having different diameters into a parallel strip using an insulating coating S. The electric wires 21a and 21b are coupled to each other at an equal array pitch by adjusting the widths of coupling portions S consisting of an insulating coating material and arranged among the electric wires 21a and 21b. Each of the first and second trunk portions 22a and 22b is formed by covering the conductor portion of each electric wire 21 with a resin member formed by extrusion molding as an insulating coating. Referring to FIG. 3, each electric wire 21 having a dot attached to its distal end is a large-diameter electric wire 21b, and each electric wire 21 having no dot is a small-diameter electric wire 21a. Each branch portion has the same structure as that shown in FIG. 4. Note that the conductor portion of each of the electric wires 21a and 21b is a multicore stranded wire. As shown in FIG. 2, the first to ninth branch portions 23, 24, 25, 26, 27, 28, 29, 30, and 31 spread inside the door D. The end portions of these branch portions except for the first and fifth branch portions 23 and 27 are respectively connected to electric devices (not shown) arranged in the door D via first to seventh connectors C1, C2, C3, C4, C5, C6, and C7. The end portion of the first trunk portion 22a is connected to a wire harness (not shown) in the body B via an eighth connector C8. The end portion of the second trunk portion 22b is connected to an electric device (a speaker for audio, a motor for powered window, etc.) in the door D via a ninth connector C9. As shown in FIG. 2, a grommet G is fitted on the first trunk portion 22a, of the wire harness 20, located between the body B and the door D so that the first trunk portion 22a can be freely bent. A tape T is wound around a portion, of the first trunk portion 22a, located near the grommet G to fix the first trunk portion 22a to the grommet G. As shown in FIGS. 2 and 3, all the first to fourth branch portions 23, 24, 25, and 26 branch off at a first branching portion 34, and the respective branch angles are fixed and held by a first adhesive tape 35 stuck on the first branching portion 34. Similarly, all the first, fifth, and sixth branch portions 23, 27, and 28 branch off at a second branching portion 36 of the second trunk portion 22b, and the respective branch angles are fixed and held altogether by a second adhesive tape 38 stuck on the second branching portion 36. The first trunk portion 22a and the first and fifth branch portions 23 and 27 have first to third clips 39, 40, and 41 (to be described later), respectively, to be attached to the door D via the clips 39, 40, and 41. The portion between the joint device 32 of the first and second branch portions 23 and 24 and the eighth connector C8 can be cut off. As shown in FIG. 5, the first joint device 32 comprises upper and lower halves 42 and 43 which are respectively brought into contact with the upper and lower surfaces of the first trunk portion 22a, an engaging/holding means for engaging/holding the upper and lower halves 42 and 43 in contact with the upper and lower surfaces of the first trunk portion 22a, and a plurality of short-circuiting metal members 45 arranged on the lower half 43 to short-circuit pairs of electric wires 21 constituting the first trunk portion 22a. The upper and lower halves 42 and 43 are formed by cutting a flat, box-like plastic member consisting of nylon or the like into halves at a middle position in the direction of thickness. Therefore, when the upper and lower halves 42 and 43 are stacked on each other with their opening portions opposing each other, a closed box-like shape is formed. The engaging/holding means are resin projections 44 arranged at the four corners of the lower half 43 to extend outside the lower half 43. When the lower and upper halves 43 and 42 are stacked on each other, the projections 44 extend through through holes 46 formed in the upper half 42 such that the distal ends of the projections 44 extend outside the upper half 42 via the through holes 46. By fusing/deforming the distal ends extending from the upper half 42, the projections 44 are fusion-bonded to the upper half 42. That is, the upper and lower halves 42 and 43 can be engaged/held in a stacked state. In addition, each engaging/holding means 44 is long enough to hold a stacked state of the upper and lower halves 42 and 43 with the first trunk portion 22a being clamped therebetween. As shown in FIG. 5, each short-circuiting metal member 45 comprises at least a pair of terminal portions 47 which bite into the insulating coating of the electric wires 21 to contact them, and a coupling portion 48 for electrically coupling the terminal portions 47 to each other. The short-circuiting metal member 45 is a plate-like member having the terminal portions 47 and the coupling portion 48 formed from one conductive metal plate. These short-circuiting metal members 45 are successively arranged on the lower half 43 to overlap along the axis of the first trunk portion 22a. Although not described with reference to the accompanying drawings, the second joint device 33 has the same arrangement as that of the first joint device 32 and is larger in size than the first joint device 32. FIGS. 6A and 6B are perspective views showing a detailed example of how the second adhesive tape 38 is used. As shown in FIGS. 6A and 6B, when the branch angles of branch portions L1, L2, and L3 with respect to the trunk portion 22 are large, the branch portions L1, L2, and L3 are bent near a branching portion B1, and the adhesive tape 38 is stuck on the branching portion B1 while it is sandwiched between two parts of the folded adhesive tape 38 from the upper and lower surfaces sides of the branching portion B1. The adhesive tape 38 is tightly stuck on the cables 22, L1, L2, and L3, which constitute the branching portion, along their outer surfaces, thereby fixing the cables 22, L1, L2, and L3. The first clip 39 mounted on the first trunk portion 22a has a pair of upper and lower casings for clamping the first trunk portion 22a from the upper and lower surface sides. The lower casing has lock portions for mounting the clip 39 on the door D at a predetermined position. The upper and lower casings are elongated members which are slightly larger in width than the first trunk portion 22a. Clamp projections are formed on two edge portions of the upper casing in the direction of width and a central portion of the lower casing in the direction of width to extend toward the opposing casings. These clamp projections serve to clamp the first trunk portion 22a when the upper and lower casings are stacked on each other. In addition, one end of the upper casing and one end of the lower casing in the longitudinal direction are pivotally coupled to each other via a pivot portion such that the upper and lower casings can be brought close to each other and separated from each other while the clamp projections oppose each other. In addition, an engaging projection and an engaging recess are formed on end portions, of the upper and lower casings, located on the opposite side to this pivot portion to oppose each other. When the upper and lower casings are stacked on each other, the engaging projection and the engaging recess are engaged with each other, thereby holding the stacked state of the upper and lower casings. A clip Cp having a function of fixing/holding a branch portion is used to fix/hold a branch portion at a branching portion and lock a branch portion to the door D. A portion of a cable is bent in the direction of thickness and formed into bellows. For example, such a portion is formed on the fifth branch portion 27 to absorb variations in dimension in the manufacturing process so as to prevent the wire harness 20 from interfering with window members (not shown) housed in the door D. In addition, as shown in FIG. 2, a mark H indicating the inspection result, type, and the like of the wire harness 20 is mounted on the second trunk portion 22b at a position between the ninth connector C9 and the second joint device 33. A stable mounting means for the second trunk portion 22b can also be attached to this mark H, similar to the first to third clips 39, 40, and 41. Steps in the construction of a wire harness will be described next with reference to FIGS. 7 to 14 and 16. FIGS. 7 to 12 are plan views showing steps of manufacturing the wire harness 20. FIG. 16 is a flow chart showing the steps in said construction. These steps will be briefly described with reference to FIGS. 7 to 12, and will be described in detail with reference to FIGS. 13 and 14. As shown in FIGS. 7 and 8, the length of a flat cable F measured (step 1) and the end portion of a trunk portion K0 constituted by a flat cable F formed by.integrating the plurality of electric wires 21 into a parallel strip using the insulating coating S is torn in accordance with the number of branch portions required, and unnecessary portions are cut off (step 2), thereby forming first to fourth branch portions K3, K4, K5, and K6. For example, FIG. 13 shows branch portions formed from the flat cable F corresponding to the wire harness 20 shown in FIG. 2. Subsequently, as shown in FIG. 9, first to fourth connectors j1, j2, j3, and j4 are respectively connected to the distal ends of the first to fourth branch portions K3, K4, K5, and K6, and a fifth connector j5 is connected to the end portion of the trunk portion K0 (step 3). In addition, a first joint device j7 is arranged near a branching portion j6 of the first to fourth branch portions K3, K4, K5, and K6 of the trunk portion K0. The first to fourth branch portions K3, K4, K5, and K6 whose branch angles are large are bent (step 4). For example, FIG. 14 shows how the first to ninth branch portions 23, 24, 25, 26, 27, 28, 29, 30, and 31 corresponding to the wire harness 20 are bent. As shown in FIG. 10, the bent portions of the first, third, and fourth branch portions K3, K5, and K6 are fixed with first and second adhesive tapes T1 and T2. As shown in FIG. 11, when fixing of the bent portions is completed, the grommet G is mounted on the bent portion of the trunk portion K0. A portion near the branching portion j6 and the second branch portion K4 are fixed with first and second clips Cp1 and Cp2. As shown in FIG. 12, a proper portion is fixed with a clip Cp (e.g., a clip Cp3). Thereafter, the wire harness 20 is received (step 5) in cover and tested (step 6). With this arrangement of the wire harness 20, a multicore circuit can be made of a single flat cable F by using the first and second joint devices 32 and 33. Therefore, an increase in the thickness of the circuit can be suppressed. In addition, even if the number of electric wires 21 integrated into a flat cable is large, the branching step, the connector mounting step, and the like are easy to perform. Because the wire harness 20 is made of a single flat cable F, the installation of the wire harness can be easily performed. Since the first and second branch portions 34 and 36 of the wire harness 20 are fixed with the adhesive tapes 35 and 38, tearing and the like of the insulating coating S of the branch portions 34 and 36 which are caused by external forces can be prevented, and damage to each branch portion after installation can also be prevented. This facilitates installation of the wire harness in a place at which it is exposed to vibrations. In addition, since the first to third clips 39, 40, and 41 are mounted on the wire harness 20, damage to the wire harness, displacement thereof, and the like caused by external forces such as vibrations can be prevented as a whole. This allows stable installation of a multicore harness in a place where it is subject to the influence of external forces. Since the fifth branch portion 31 has an extendible portion 57, the branch portion can be easily installed in the door D. In addition, the wire harness 20 is formed from a single flat cable F and hence has uniform strength. This makes the wire harness 20 have antivibration and anti-deformation effects. Therefore, the number of extendible portions 57 and clips 39, 40, and 41 to be installed can be decreased, and a reduction in manufacturing cost and an improvement in manufacturing efficiency can be achieved. According to the steps of constructing the wire harness 20, since a single flat cable is processed, positioning in the cutting step, the connector mounting step, and the like is facilitated. Therefore, the manufacturing efficiency can be improved, and each manufacturing step can be easily automated. The third embodiment of the present invention will be described next with reference to FIG. 15. Referring to FIG. 15, reference numeral 60 denotes a wire harness. In this wire harness 60, the first, second, and third branch portions 24, 25, and 26 of the wire harness 20 shown in FIGS. 2 and 4 are formed from another flat cable F2. The wire harness 60 is substantially constituted by first and second flat cables F1 and F2 each formed by integrating a plurality of electric wires as shown in FIG. 4 into a parallel strip using an insulating coating. The wire harness 60 comprises first and second trunk portions 62a and 62b, first to ninth branch portions 63, 64, 65, 66, 67, 68, 69, 70, and 71 formed by branching one end portion of each of the first and second trunk portions 62a and 62b, a first joint device 72 (indicated by the broken line) arranged on the first trunk portion 62a to connect two or more electric wires of the electric wires constituting the first trunk portion 62a so as to electrically short-circuit the branch portions 63 and 64, and a second joint device 73 (indicated by the broken line) arranged on the second trunk portion 62b to connect two or more electric wires of the electric wires 61 constituting the second trunk portion 62b so as to electrically short-circuit the branch portions 63 and 67. The first and second trunk portions 62a and 62b are formed by integrating large numbers of electric wires having different diameters into parallel strips using the insulating coating S. The first trunk portion 62a comprises a first sub-trunk portion 74 of the first flat cable F1, and a second sub-trunk portion 75 of the second flat cable F2. The second branch portion 64 comprises second and third sub-trunk portions 77 and 78 of the second flat cable F2. The third branch portion 65 is the sub-branch portion of the second flat cable F2. With this arrangement of the wire harness, a multicore circuit can be made of two flat cables. Therefore, the number of electric wires 21 can be decreased, and the first and second joint devices 72 and 73 do not occupy a wide space, and especially the multicore harness occupies a very small space and can be easily designed. With this arrangement of the wire harness, the measuring, tearing and cutting of the two flat cables F1 and F2 can be easily automated. Therefore, demerits due to the increase in the number of flat cables can be decreased, and the harness is small in size and can be easily designed. The fourth embodiment of the present invention will be described next with reference to FIG. 17. Similar to each embodiment described above, a wire harness 100 of this embodiment is designed such that two branch portions 101 and 102 are formed by tearing one end of a single flat cable F. A connector 104 is attached to the end portion of a trunk portion 103. Connectors 104, 105 are attached to the ends of the branch portions 101 and 102. A joint device 108 is arranged on the trunk portion 103 to short-circuit predetermined electric wires 107 of the branch portion 101 and with wires of the branch portion 102. However, the wire harness according to this embodiment of the present invention is different from each embodiment described above in the manner of handling the electric wires 107 of the trunk portion 103. The wire harness 100 according to the fourth embodiment will be described below in comparison with the first embodiment shown in FIG. 1. In the first embodiment, the electric wires 11 of the branch portions 13 and 14 short-circuited by the joint device 15 are designed not to be connected to the connector 16 of the trunk portion 12. For this purpose, these electric wires are cut, as indicated by the broken lines in FIG. 1. Therefore, in the wire harness 10 in FIG. 1, terminals (not shown) near the center portion of the connector 16 to which the electric wires 11 indicated by the broken lines were expected to be connected are idle terminals corresponding to the number of electric wires 11 to be short-circuited As indicated by the broken lines in FIG. 17, in the wire harness 100 of the fourth embodiment, electric wires 107a which are not connected to the connector 104 of the trunk portion 103 are arranged at one end portion of the flat cable F in the direction of width by the number of electric wires 107 short-circuited between the branch portions 101 and 102, i.e., the number (six in FIG. 17) of electric wires 107 connected to short-circuiting metal members 109. All electric wires 107b except for the electric wires 107a are connected to the connector 104 of the trunk portion 103. Of the electric wires 107b connected to the connector 104 of the trunk portion 103, the electric wires 107b short-circuiting the branch portions 101 and 102 have cut portions 110 formed by partly cutting/removing the electric wires 107b between a position where the short-circuiting metal members 109 are attached and a position where the electric wires 107b are connected to the connector 104. With these cut portions 110, conduction between the connector 104 and the electric wires 107b short-circuiting the branch portions 101 and 102 is disrupted. In addition to the short-circuiting metal members 109 for short-circuiting the branch portions 101 and 102, the wire harness 100 of the fourth embodiment includes short-circuiting metal members 111 for short-circuiting the cut electric wires 107b, arranged between the cut portions 110 and the connector 104, and the electric wires 107a which are not connected to the connector 104 and arranged at one end portion in the direction of width. With these short-circuiting metal members 111, the electric wires 107a, of the branch portion 101, which are not connected to the connector 104 are connected to terminals, in the connector 104, which are rendered unnecessary because of short circuit between the branch portions 101 and 102. As the short-circuiting metal member 111, the joint device 108, and the like, members like those shown in FIG. 5 may be used. Alternatively, a short-circuiting metal member 111 obtained in the following manner may be used. As shown in FIG. 18A, press contact terminals 111a are pressed against the electric wires 107b having the cut portions 110 formed by punching the electric wires 107b to be short-circuited. As shown in FIG. 18B, the press contact terminals 111a are coupled to each other by resistance-welding a tape electric wire 111b as a flat rectangular conductor. Referring to FIG. 18A, reference numeral 112 denotes an insulating cover which is engaged with the press contact terminal 111a pressed against the electric wire 107b to hold the press contact terminal 111a in a press contact state. In this case, the cut portions 110 may be covered with the upper and lower casings of the joint device 108 or an adhesive tape 113 shown in FIG. 18C, together with the short-circuiting metal members 111, so as to prevent the conductors of the electric wires 107b from being exposed. In addition, processes such as fixing of bent portions with an adhesive tape and mounting of clips, i.e., processes other than handling of the electric wires 107 of the trunk portion 103, may be performed in the same manner as in each embodiment described above. According to the fourth embodiment, the idle terminals arranged near the central portion of the connector 15 in the first embodiment shown in FIG. 1 can be eliminated, and all the terminals can be effectively used. Therefore, the total number of terminals of the connector 104 can be decreased, and the width of the connector can be reduced. Furthermore, since the trunk portion 103 of the flat cable F connected to the connector 104 is formed by integrally coupling the electric wires 107 to each other with an insulating coating, positioning of the connector 104 and the flat cable F is further facilitated as compared with the first embodiment having cut portions partly. Steps of constructing the wire harness 100 of the fourth embodiment will be described next with reference to the flow chart shown in FIG. 19. As shown in FIG. 19, although the flow chart for this construction is almost the same as that shown in FIG. 16, the method is characterized in the contents of the tearing/cutting step and the connector J/C press contact step. The tearing/cutting step (step 12) includes the step (step 13) of cutting the electric wires 107a from one end portion of the flat cable F in the widthwise direction by the same number as that of the electric wires 107a short-circuited between the branch portions 101 and 102 at the end portion, of the flat cable F, to which the connector 104 of the trunk portion 103 is attached, and the subsequent connector J/C press contact step (step 15) includes the step (step 14) of forming the cut portions 110 for partly cutting the electric wires 107b, short-circuited between the branch portions 101 and 102, at intermediate positions between the short-circuiting portions and the connector 104. The connector J/C press contact step (step 15) includes the step (step 16) of attaching the connector 104 such that all the terminals are connected to the electric wires 107b equal in number to the terminals of the connector 104 arranged at the end portion of the trunk portion 103, and the step of short-circuiting portions, of the electric wires 107b, located between the connector 104 and the cut portions 110 formed in the electric wires 107b in the above step and the electric wires 107a which are not connected to the connector 104, by using the short-circuiting metal members 111. Steps 17 to 19 are performed as well as steps 4 to 6 in FIG. 16. According to these steps for constructing the wire harness 100, the width of the connector 104 attached to the trunk portion 103 can be easily decreased substantially by only adding a simple operation of short-circuiting a plurality of electric wires 107a and 107b using the short-circuiting metal members 111. Each step can be easily performed by avoiding a complicated operation of positioning a plurality of flat cables F to one connector 104 at once. In addition, production of defective products can be prevented by improving the positioning precision. Furthermore, since the wire harness 100 constructed by the steps of the fourth embodiment includes no unnecessary electric wires which are not connected to a connector, the total weight of the wire harness can be reduced. This wire harness is effective especially when the distance from a short-circuiting portion to the connector 104 of the trunk portion 103 is long. Steps S12 to S14 and steps 15 and 16 may be performed simultaneously.

Claims: A wire harness (10, 20, 60, 100) comprising: a substantially flat cable including a plurality of parallel electric wires (11) covered with an insulating coating for insulating said wires and for maintaining said wires substantially parallel, said cable including a trunk portion (12, 22a, 62a, 103) separating into at least first (13) and second (14) branch portions; a connector (16, C8, j5, 104) mounted to electric wires of the trunk. portion and mounted on an end portion thereof; and a joint device (15, 32, 72, 108) spaced from said connector and electrically connecting at least two wires (11), including a first wire (11) extending from said joint device (15, 32, 72, 108) into said first branch portion (13); and a second wire (11) extending from said joint device into said second branch portion (14), said joint device thereby short circuiting said first and second branch portions (13, 14); wherein said first and second wires are electrically disconnected from said connector (16, C8, j5, 104) between said joint device (15, 32, 72, 108) and said connector. A wire harness according to Claim 1 wherein: said electric wires (11) include a first group of wires (21a) having a first diameter, and a second group of wires (21b) having a second diameter greater than said first diameter, wherein the insulating coating covering said first group of wires (21a) has a first thickness and the insulating coating covering said second group of wires (21b) has a second thickness that is smaller than said first thickness. A wire harness according to Claim 2, wherein said joint device electrically connects a first wire from said first group of wires and a second wire from said first group of wires. A wire harness according to Claim 2, wherein said joint device electrically connects a first wire from said first group of wires and a second wire from said second group of wires. A wire harness according to any one of Claims 2 to 4 wherein all of the wires of each of the first (21a) and the second (21b) groups of wires defining said cables are separated from one another with substantially the same pitch (S) . A wire harness according to Claim 1 wherein there is: a first trunk portion (22a) and a second trunk portion (22b) ; the first trunk portion (22a) separating into at least a first (23) and a second (24) branch portion; a first joint device (32) provided on said first trunk portion (22a) to electrically connect at least two wires, including a first wire extending from said first joint device (32) into said first branch portion (23); and a second wire extending from said first joint device (32) into said second branch portion (24); said second trunk portion (22b) separating into a first branch portion (23) that is also the first branch portion (23) of the first trunk portion (22a); and separating also into at least one further branch portion (36); and a second joint device (33) provided on said second trunk portion (22b) to electrically connect at least two wires including a first wire extending from said second joint device (33) into said first branch portion (23); and a second wire extending from said second joint device (33) into said at least one further branch portion (36) of said second trunk portion (22b). The wire harness of Claim 6, wherein at least two of the electric wires defining said first and second trunk portions have different diameters. The wire harness of Claim 6, wherein said first trunk portion includes a first sub-trunk portion of said first cable, and a second sub-trunk portion of said second cable. The wire harness of Claim 1, or Claim 2, or Claim 6 wherein said joint device includes an upper casing portion (42), a lower casing portion (43), engaging/holding means (44) for engaging/holding said upper and lower casing portions in a state wherein said upper and lower casing portions are respectively in contact with the upper and lower surfaces of said trunk portion; and a short circuiting member (45) arranged in at least one of said upper and lower casing portions to electrically connect said at least two wires. A wire harness according to Claim 1 wherein: said trunk portion (103) includes first (107a) and second (107b) groups of wires; a connector (104) provided at a distal end of said trunk portion (103), wherein said second group of wires (107b) are electrically connected to said connector (104), and said first group of wires (107a) are not electrically connected to said connector (104), and wherein a portion of said second group of wires (107b) and all of said first group of wires (107a) define said first branch portion (101), and the remainder of said second group of wires (107b) define said second branch portion (102) ; a first short circuiting member (109) electrically connecting a wire from said second group of wires (107b) defining said first branch portion (101) and a wire from said second group of wires (107b) defining said second branch portion (102); and a second short circuiting member (111) electrically connecting a wire from said first group of wires (107a) defining said first branch portion (101) and a wire from said second group of wires (107b) defining said second branch portion (102); wherein a cut portion (110) is provided at a position along each of the wires of said second group of wires (107b) electrically connected by said first short circuiting member (109) between said first short circuiting member (109) and said connector (104). The wire harness of Claim 9, wherein each said short circuiting member (45) includes a pair of terminal portions (47) for penetrating the insulating coating of the respective electrical wires and a coupling portion (48) electrically connecting said terminal portions. The wire harness of Claim 10, wherein each said short circuiting member (45) includes a pair of terminal portions (47) for penetrating the insulating coating of the respective electrical wires and a coupling portion (48) electrically connecting said terminal portions.

Inventors: AKASHI KAZUYA, ENOMOTO KAZUO, GOSHIMA NAOKI, HAMADA ATSUSHI, HASEGAWA TAKESHI, KAWAMURA HIDEKI, TAKAHASHI KENICHIROU, TAKEMURA YASUO, YAMAZAKI HIDETAKA, AKASHI, KAZUYA, ENOMOTO, KAZUO, GOSHIMA, NAOKI, HAMADA, ATSUSHI, HASEGAWA, TAKESHI, KAWAMURA, HIDEKI, TAKAHASHI, KENICHIROU, TAKEMURA, YASUO, YAMAZAKI, HIDETAKA
Applicants: FUJIKURA LTD, FUJIKURA LTD.
Application year: 1995
Main classification: H01R12
IPC codes: H01R43