A method for producing a wiring harness and a wiring harness producing apparatus

Abstract: To enhance a degree of freedom in producing a wiring harness having a curved portion. Placing tables 28, film adhering tables 27 and connector mounting tables 24 are individually formed and rearranged so as to conform to a desired wiring path. A plurality of wires 11 are linearly placed in parallel with each other on each placing table 28, and a wire length adjusting tool 14 formed with steps 15 with a specified inclination is brought into contact with the wires 11 to push them down, thereby setting different loosened lengths for the respective wires 11. Films 12 are adhered to the linear portions of the wires 11 to hold the different loosened lengths unchanged.

Description: The present invention relates to a method for producing a wiring harness and a wiring harness producing apparatus, e.g. used in an internal wiring of an office automation (OA) equipment, a home electric appliance or an automotive vehicle. US-A-5 230 146 discloses a method for assembling a wire harness and an apparatus for carrying out the method. Main wires are arranged horizontally and in parallel with each other. A required portion of each main wire held by a cover installed at the leading end portion of a rod is dropped to a predetermined lower portion so as to obtain a branch wire. A known wiring harness for electrical connection arranged in an OA equipment, a home electric appliance or an automotive vehicle has conventionally been mounted as follows. Specifically, a plurality of wires 1 for connecting a CPU, a display device and a variety of switches are bundled, e.g. as shown in FIG. 16; jigs (not shown) or the like for holding a connector 3 and the wires 1 are arranged on a flat plate in accordance with an actual arrangement of the wiring harness; the wires 1 are arranged in accordance with the jigs; an adhesion tape 2 for protection is wound around the bundle of wires 1; the taped wire bundle is covered with a casing to be held in a specified configuration; and the cased wire bundle is so mounted as to conform to a wiring path inside an OA equipment, a home electric appliance or an automotive vehicle (first prior art). However, according to the first prior art, since the adhesive tape 2 is wound around the wire bundle after the wire bundle is manually arranged in accordance with the jigs during the production, it takes a large amount of time to wind the adhesive tape 2 after the arrangement of the wire bundle, thereby lowering a work efficiency. In view of the problem of the first prior art, there are frequently used flat cables having a multitude of contacts such as flexible print cables (FPC) in which a pattern of conductive paths 4 is printed on a flexible base film 5 which is then overlaid with a cover film 6, e.g. as shown in FIGS. 17 and 18 (second prior art). However, in the case of a complicated wiring harness having curved conductive paths 4, etching mask is applied for each pattern in a production process, and after the patterns are formed in a large base film Dk, a patterned portion is punched to be cut off as shown in FIG. 18. Thus, large apparatuses such as an etching apparatus and a cutting apparatus are required. Further, the use of the large base film Dk necessitates a large work space, leading to a poor space efficiency. Further, as shown in FIG. 19, there is also a known method for linearly arranging a plurality of strip-like conductors 1 in parallel with each other, laying films 5, 6 on the opposite sides of the conductors 1, and folding the thus obtained flat cable according to a wiring path (third prior art). According to this method, the apparatuses required for the second prior art can be dispensed with. However, in the wiring harness obtained according to the third prior art, folded portions 7 may be damaged or a portion between the folded portions 7 may be deformed in such a three-dimensional manner to part from the remaining parts of the wiring harness due to the elastic restoration of the folded portions 7 as shown in FIG. 20. This presents a problem that the configuration of the wiring harness cannot stably conform to the wiring path. The respective conductors 1 may accurately be arranged along the wiring path into a corresponding configuration and at specified intervals. However, this requires a large amount of time for aligning the configuration of the conductors 1, leading to a poor time efficiency. Further, since a large film corresponding to the wiring path is required, the problem of the second prior art is left unsolved. It is also necessary to easily cope with a design change of a wiring harness while solving the above problems. Particularly, in the case of the second prior art, the large apparatuses are forced to be changed to cope with a design change of a wiring harness, considerably increasing a production cost. An object of the present invention is to provide a wiring harness, a method for producing a wiring harness and a wiring harness producing apparatus having or allowing for a simple construction of the apparatus, which is capable of easily producing a wiring harness without folding or bending and easily coping with a design change. This object is reached by a method for producing a wiring harness according to claim 1 and a wiring harness producing apparatus according to claim 4. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a method for producing a wiring harness, comprising: a first step of linearly arranging a plurality of wires substantially in parallel with each other, a second step of setting different loosened lengths for the wires of the specified wire group by pressing a tool formed with steps with a specified inclination against the wires or bringing a loosened length adjusting means in close contact with the respective wires, to compensate for length differences between adjacent arcs of the wires of the finished wiring harness, and a third step of fixing a plurality of wires, in particular by adhering a film or the sheet member over the plurality of wires, outside the loosened lengths thereof, wherein the loosened length adjusting means comprises a plurality of steps or recesses, extending at an angle different from 0° or 180°. According to a preferred embodiment, the method comprises a fourth step of establishing the desired position or configuration of the curved and linear portions of the wiring harness and adhering the protection film to the curved portion. Preferably, in the first step, the plurality of wires are arranged to extend over an opening which is provided in a predetermined or predeterminable position of a surface of a placing table means and, in particular in the second step, the respective wires are pushed into the opening using the loosened length adjusting means. According to the invention, there is further provided an apparatus for producing a wiring harness, in particular using the method of the invention, comprising: wire feeding means for feeding a plurality of wires, a placing table means comprising at least one table module, for linearly placing the plurality of wires and loosened length adjusting means provided with wire positioning means, comprising a plurality of steps or recesses, extending at an angle different from 0° or 180°, which set different loosened lengths of the respective wires when brought into pressing contact with the wires on or at the placing table means. According to a preferred embodiment of the invention, steps or recesses have a specified inclination, which is defined in accordance with the desired setting of the different loosened lengths of the respective wires. Preferably the apparatus further comprises wire aligning means for substantially parallelly aligning the plurality of wires fed from the wire feeding means. Further preferably, at least one opening is formed in a predetermined or predeterminable position of a surface of the placing table means, in particular in a placing table module thereof or between two adjacent placing table modules thereof, through or into which the loosened length adjusting means is movable to push the respective wires after being brought into contact with the respective wire positioning means, in particular steps or recesses, thereof, wherein the opening has preferably a width along the longitudinal direction of the wires such that the wires are smoothly bent when they are pushed by the respective wire positioning means. Preferably, the placing table means further comprises a sheet member adhering table module for adhering a sheet member to the linear portion of the plurality of wires after the setting of the different loosened lengths and/or a protection film adhering table module for adhering a protection film to the curved portion of the plurality of wires. Further preferably, the placing table means further comprises at least one connector connecting table module for connecting at least one connector with at least a part of the plurality of wires after the setting of the different loosened lengths thereof by the loosened length adjusting means. According to still a further preferred embodiment, the portion of the loosened length adjusting means coming into contact with the wires and/or the edges of the placing table means is/are rounded off. Preferably, the height hn of the n-th step corresponding to the n-th wire of the plurality of wires is approximately given by the following formula: h n ≈ L n 2 - a 2 = 1 2 L 2 n - a 2 wherein Ln is the length of the bent portion of the n-th wire and a is the width of an opening of the placing table means along the longitudinal direction of the wires, wherein the length Ln is preferably given by the following approximative equation: L n ≈ 2π n w ε[°] 360° wherein ε is the bending angle by which the wires are bent and w is the distance between adjacent wires, wherein the equations for the height hn of the n-th step and/or for the length Ln of the n-th wire is/are preferably adopted for n≥4. Thus the height hn can be determined within a predetermined level of accuracy. Most preferably, the wire positioning means, in particular the steps or recesses are spaced from each other, preferably in the lateral direction of the loosened length adjusting means, depending upon or in correspondence with the spacing(s) of the wires. According to a preferred embodiment of the invention, there is provided a wiring harness producing apparatus, comprising: wire feeding means for feeding a plurality of wires, wire aligning means for substantially parallelly aligning the plurality of wires fed from the wire feeding means, a placing table for substantially linearly placing the plurality of wires aligned in parallel with each other by the wire aligning means, loosened length adjusting means preferably formed with steps with a specified inclination which are pressed against the wires on the placing table to loosen the respective wires by different lengths, a film adhering table for linearly placing the plurality of wires aligned in parallel with each other by the wire aligning means and adhering a film to the plurality of wires after the loosened lengths thereof are set by the loosened length adjusting means, and a connector connecting table for linearly placing the plurality of wires aligned in parallel with each other by the wire aligning means and connecting a connector with the plurality of wires after the loosened lengths thereof are set by the loosened length adjusting means, wherein the placing table, the film adhering table and the connector connecting table are individually detachable. Accordingly , since the placing table, the film adhering table and the connector connecting table are individually detachable, the wiring harness producing apparatus can be changed in various manners by changing their combination. This leads to an enhanced degree of freedom in designing wiring harnesses. Preferably, an opening for allowing the tool or loosened length adjusting means to set the loosened lengths by being brought into contact with the wires and pushing them down is formed in a specified position of the upper surface of the placing table. The plurality of wires are linearly placed in parallel with each other on the placing table to extend over the opening, and the loosened length adjusting means is brought into contact with the wires and pushed down in the opening to set the loosened lengths for the respective wires. Accordingly, the wires are allowed to have a curved portion corresponding to a desired wiring path only by a very easy operation. Thus, the opening for allowing the tool or loosened length adjusting means to set the loosened lengths by being brought into contact with the wires and pushing them down is formed in the specified position of the upper surface of the placing table. Accordingly, the plurality of wires are linearly placed in parallel with each other on the placing table to extend over the opening, and the loosened length adjusting means is brought into contact with the wires and pushed down in the opening to set the loosened lengths for the respective wires. Therefore, the wires are advantageously allowed to have a curved portion corresponding to a desired wiring path only by a very easy operation. According to a further preferred embodiment of the inventive method, a plurality of wires are linearly placed in parallel with each other on a placing table, and a tool formed with steps with a specified inclination is pressed against the wires to set different loosened lengths for the respective wires. In this way, a curved portion in conformity with a desired wiring path can easily be formed by the respective wires while space efficiency is improved by linearly arranging the wires. Further, a film is or may be adhered to the plurality of wires having the loosened lengths thereof set in order to hold the different loosened lengths unchanged. Thus there is provided a wiring harness producing method for the easy production of a wiring harness without partly folding the wiring harness along its wiring path having a curved portion by only using a producing apparatus of simple construction. Preferably, an opening is formed in a specified position of the upper surface of the placing table. The plurality of wires are linearly placed in parallel with each other to extend over the opening, and the loosened lengths are set by bringing the tool into contact with the wires and pushing them down in the opening. Thus, a curved portion in conformity with a desired wiring path can be formed by the respective wires only by a very easy operation. According to a further preferred embodiment of the invention, a wiring harness producing apparatus for realizing the method according to the above method comprises: wire feeding means for feeding a plurality of wires, wire aligning means for parallelly aligning the plurality of wires fed from the wire feeding means, a placing table for linearly placing the plurality of wires aligned in parallel with each other by the wire aligning means, and loosened length adjusting means formed with steps with a specified inclination for setting different loosened lengths for the respective wires by being brought into pressing contact with the wires on the placing table. Preferably, an opening for allowing the tool or loosened length adjusting means to set the loosened lengths by being brought into contact with the wires and pushing them down is formed in a specified position of the upper surface of the placing table. Further preferably, the wiring harness producing apparatus further comprises a film adhering table for adhering a film to the plurality of wires having been loosened by the different lengths. Thus the film can easily be adhered. These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings in which: FIG. 1 is a plan view of a wiring harness produced by a producing apparatus according to one embodiment of the invention, FIG. 2 is a diagram of a curved portion of the wiring harness of FIG. 1 in which the respective wires are bent at 90°, FIG. 3 is a diagram of the wires having the lengths thereof adjusted by a tool, FIG. 4 is a front view of the tool used to produce the wiring harness of FIGS. 1 and 2, FIG. 5(A) is a perspective view showing an operation of adjusting the lengths of the wires at the curved portion using the tool of FIG. 3, FIG. 5(B) is a schematic sectional view showing in an operation of the wire length adjusting tool pressing the wire into the opening, FIG. 5(C) is a simplified sectional view showing a simplified scheme for determining the approximative heights of the steps of the loosened length adjusting means, FIG. 6 is a plan view of the producing apparatus according to the embodiment, FIG. 7 is a plan view of a wiring harness produced by a producing apparatus according to another embodiment of the invention, FIG. 8 is a diagram of a curved portion of the wiring harness of FIG. 7 in which the respective wires are bent at 45°, FIG. 9 is a front view of a tool used to produce the wiring harness of FIGS. 7 and 8, FIG. 10 is a plan view of a wiring harness produced by a producing apparatus according to a still another embodiment of the invention, FIG. 11 is a plan view of the producing apparatus according to the still another embodiment of the invention, FIG. 12 a plan view of a wiring harness produced by a producing apparatus according to a further another embodiment of the invention, FIG. 13 is a plan view of the producing apparatus according to the further another embodiment of the invention, FIG. 14(A) is a front view of a tool used to produce the wiring harness of FIG. 14(B), FIG. 14(B) a plan view of a wiring harness having differently bent bent portions, which is produced by a producing apparatus according to a further another embodiment of the invention, FIG. 15 a plan view of a wiring harness having differently bent bent portions, which is produced by a producing apparatus according to still a further another embodiment of the invention, FIG. 16 is a perspective view of a wiring harness for electrical connection according to first prior art, FIG. 17 is a perspective view partly in section of a wiring harness for electrical connection according to second prior art, FIG. 18 is a plan view showing a production process of the wiring harness according to the second prior art, FIG. 19 is a diagram of a folded wiring harness according to third prior art, and FIG. 20 is a diagram showing the wiring harness of FIG. 19 in which folded portions are elastically restored. FIG. 1 is a diagram of a wiring harness produced by a producing apparatus according to one embodiment of the invention. In this wiring harness, a plurality of wires 11 are arranged substantially in parallel at substantially even intervals on the same plane, and are partly fixed by adhering films 12. Films 12 (sheet members) which may be used to fix the wires 11 and may be made of, e.g. polyvinyl chloride (PVC), polyethylene (PE) or a thin metal plate are adhered to parts of the wires from above using a cold adhesive or thermoplastic adhesive. Particularly, in order to conform to a complicated wiring path having curved portions, all wires 11 are curved along substantially concentric arcs at substantially even intervals in each curved portion 13. For a producing method to be described later, the films 12 may be adhered to linear portions 13b of the wires 11, but not to the curved portions 13a thereof. Therefore, the respective wires 11 used are of the type which are covered with insulating coatings made of polyvinyl chloride (PVC) or polyethylene (PE). Depending on an environment where the wiring harness is used, the wiring harness may be required to be heat resistant. In such a case, a fluorocarbon resin (Trademark: "Teflon") may be used as a coating material of the wires 11; enamelled wires may be used as wires 11; polyimide (PI) or polyphenylene sulfide (PPS) as a product may be used as films 12 and the wires 11 and the films 12 may be fixed using a thermosetting adhesive. As shown in FIG. 1, no film is adhered to the wires 11 in the curved portions 13. However other curvatures or bendings are possible. Therefore, the respective wires 11 used are of the type which are covered with insulating coatings. Although four wires 11 are arranged in this embodiment, the number of the wires 11 is not limited to four provided that the wires 11 are arranged in substantially parallel at preferably even intervals or spacings or pitches on the same plane, at least within predetermined tolerances. Also substantially uneven intervals of the wires 11 may be chosen, i.e. the wires 11 must not be equally spaced. FIG. 2 is a diagram showing the wires 11 the longitudinal direction thereof is curved by an angle of 90° in the curved portion 13. Since the wires 11 (11a to 11d) are spaced by a specified distance w in the curved portion 13 of the wiring harness, the lengths of the wires 11 need to be different or to have different lengths. Assuming that a spacing between the wires 11a to 11d is w and the radii of curvature of the wires 11a to 11d are w, 2w, 3w, 4w, respectively, lengths L1, L2, L3, L4 of the wires 11a to 11d in the curved portion 13 are each a quarter of a circumference of a circle defined by the corresponding radius of curvature: L1 = (2π·w)/4 = πw/2 L2 = (2π·2w)/4 = πw L3 = (2π·3w)/4 = 3πw/2 L4 = (2π·4w)/4 = 2πw. Differences in length between the neighboring wires are: L2 - L1 = (πw) - (πw/2) = πw/2 L3 - L2 = (3πw/2) - (πw) = πw/2 L4 - L3 = (2πw) - (3πw/2) = πw/2. Thus, the differences in length between the neighboring wires need to be set at (πw/2). Although a method of manually arranging the wires 11 along the wiring path or aligning the wires 11 using a jig such as a mold may be adopted, such a method is poor in work efficiency and space efficiency. Accordingly, in this embodiment, the lengths of the wires 11 are differed in the following manner. After the wires 11 are linearly arranged substantially in parallel with each other as indicated in broken lines in FIG. 3, a wire length adjusting tool or means 14 (loosened length adjusting means, shown in FIG. 4) formed with bevelled portions or grooves or recesses or steps 15 of specified height ΔH at predetermined or predeterminable intervals (w) of the wires 11a to 11d is used to push or displace the wires 11a to 11d in a predetermined or predeterminable direction, e.g. down, to loosen them by specified lengths, thereby suitably adjusting the lengths of the wires 11a to 11d to form the curved portion 13 as indicated by solid lines in FIG. 3. The respective steps 15 of the wire length adjusting tool 14 are substantially in the form of an arcuate recess so as to prevent the wires 11a to 11d from getting out of the steps 15. A producing apparatus preferably used is as shown in FIG. 6. This apparatus includes a wire feeder 21 (wire feeding means) having a plurality of wire feeding drums 20 (of which five are shown as an example) to simultaneously feed the wires 11, a wire aligning unit 22 (wire aligning means) formed with grooves 22a for aligning the spacing (w) of the plurality of fed wires 11, connector connecting units 24 (connector connecting tables or placing table means) generally in use for connecting a specified connector 23 with the wires 11 and/or for placing the wires 11 in a predetermined or predeterminable arrangement, circuit or wire length adjusting units 25 for adjusting the length of the respective wires 11 (11a to 11d) forming circuits, preferably using the aforementioned wire length adjusting tool 14, and wire arrangement tables 27 (film adhering tables or wire portion fixing units) for fixing or securing fixing means 12 to predetermined or predeterminable portions or positions of the wires 11, preferably for adhering (or applying) films 12 or the like holding means to the wires 11 between the connector connecting unit 24 and the circuit length adjusting unit 25 and between the circuit length adjusting units 25. In each circuit length adjusting unit 25, an opening 29 for allowing the wires 11 to be pushed down by the wire length adjusting tool 14 to be loosened is formed in the middle of the upper surface of a placing table 28 as shown in FIG. 5. The wire aligning unit 22, the connector connecting units 24, the placing tables 28 of the circuit length adjusting units 25 and the wire arrangement tables 27 are set to have substantially the same height. These units are detachable as individual units so that their combination can easily be changed in accordance with a wiring path or may be unitarily or integrally formed. The length Ln of the curved portion 13 of the n-th wire of the plurality of wires 11 corresponds to a height hn of the recess or step 15, by which the n-th wire is to be pressed into the opening 29, wherein the height hn is referred to a reference height 14h (FIG. 4) and the height of the n-th step ΔHn is given by the formula: Δ H n = h n - h n -1 wherein the heights ΔHn are preferably all equal, if the wires 11 are to be arranged with a single bending or angle ε. In case the wires 11 shall be arranged with two or more different angles ε, ε', ε", etc. the heights ΔHn of the steps 15 are preferably groupwise equal (as e.g. in FIG. 14(A) to be described later). A relationship between the height hn of the n-th step 15 and the length Ln of the n-th wire of the plurality of wires 11 can be approximated, by assuming the geometrical dimensions as given in the schematic drawing of FIG. 5(C). If b is the thickness of the wire length adjusting tool 14 in a longitudinal direction of the wires 11 and a is the width of the opening 29 in the same direction, then approximately: L n ≈ b + 2 a - b 2 + h 2 n Thus the height hn of the n-th step is approximately given by the following equation: h n ≈ L n - b 2 - a - b 2 = 1 2 L 2 n - a 2 -2 b ( L n - a ) The equation for the height hn can be even more simplified by assuming the arrangement of the wire 11 as shown in FIG. 5(C), i.e. by taking the limes for b→0 : h n ≈ L n 2 - a 2 = 1 2 L 2 n - a 2 This equation may be adopted for n≥3, preferably for n≥4, since for smaller n the deviations could be too big and thus the precision of the wire arrangement could lie below a required error standard. Preferably the tip or extremity 15r of the step or recess 15 may be rounded of as shown in FIG. 5(B) as phantom line for avoiding damages to the wires 11 and for reducing even more the deviations or errors, when calculating the height hn of the steps 15 by the above simplified formula or equation (FIG. 5(C)). Moreover the edges 28r of the placing table means or units 28 may be rounded off (FIG. 5(B)) for avoiding damages to the wires 11 and allowing for a smooth bending thereof, when the length adjusting means 14 are inserted into the opening 29. Furthermore the opening 29 should have such a width a, that the wires 11 are not damaged, when the wire length adjusting tool 14 is inserted thereinto, in particular for avoiding wedging or clipping of the wires 11 by the edges of the wire length adjusting tool 14 and/or damages caused by a too strong bending of the wires 11, when the gap or interstice or clearance between the edge of the placing table means or connector connecting unit 24 and the loosened length adjusting means 14 is too small. In other words, the opening 29 has such a width a along the feeding direction P or longitudinal direction of the wires 11, that the wire length adjusting tool 14 can be loosely fitted or inserted into the opening 29 with the wires 11 arranged therebetween such that the wires 11 are not damaged, e.g. by wedging, buckling or too strong bending. Furthermore the steps or recesses or bevelled portions 15 may be spaced according to the distance or pitch of the wires 11. In FIGS 4 and 5 the distance w between the wires 11 is equal for all the wires 11 and thus the corresponding steps 15 are equally spaced from each other. In case the wires are not equally spaced (not shown), the steps 15 are correspondingly also not equally spaced. In other words, the steps or recesses or bevelled portions 15 are formed in correspondence to the positions of the respective wires 11 to be displaced. Preferably the wire length adjusting tool 14 is produced or formed having an inclined side, into which recesses 15 are formed in accordance with the corresponding position of the wires 11 to be displaced. Next, a method for producing a wiring harness using the aforementioned wire length adjusting tool 14 and producing apparatus is described. First, the wires 11 are fed from the plurality of wire feeding drums 20 of the wire feeder 21, and are linearly placed in parallel with each other on the upper surfaces of the connector connecting units 24, of the placing tables 28 of the circuit length adjusting units 25, and of the wire arrangement tables 27 while being passed along the grooves 22a of the wire aligning unit 22 so as to space the wires 11 by a specified width w. Subsequently, the steps 15 of the wire length adjusting tool 14 are brought into contact with the wires 11 (11a to 11d) extending in or over the opening 29 preferably in the middle of the placing table 28 as shown in FIG. 5, and pushed down by a specified distance to loosen the wires 11a to 11d by the distances corresponding to height hn of the respective steps 15. At this time, the wires 11 are fed from the respective wire feeding drums 20 by the loosened lengths. The wire length adjusting tool 14 may be automatically pushed down using an electrically or electronically controlled elevating device and/or manually pushed down by an operator. Thereafter, the specified films or fixing means 12 are adhered to the wires 11 from above at the wire arrangement tables 27 to fix the wires 11, in particular in or at the linear portions of the wires 11, and the specified connectors 23 are connected with the wires 11 by the connector connecting units 24, thereby completing the wiring harness shown in FIG. 1. Hard molded parts may be used instead of the aforementioned films 12. In such a case, if the molded parts are provided with a locking mechanism used to mount the wiring harness on an apparatus such as an OA equipment, a home electric appliance or an automotive vehicle, the wiring harness can easily be mounted in a later process. In the case that the longitudinal direction of the wires 11 needs to be bent at an angle of, e.g. 45° in the curved portion 13 as shown in FIGS. 7 and 8, the height difference ( ΔHn) between adjacent steps 15 of the wire length adjusting tool 14 may be so set as to conform to the difference ( L n - L n -1 ) in length between the wires 11 as follows. If the spacing between the wires 11 is w and the radii of curvature of the wires 11 are w, 2w, 3w, 4w, respectively, lengths L1, L2, L3, L4 of the wires 11a to 11d in the curved portion 13 are each one eighth of a circumference of a circle defined by the corresponding radius of curvature: L1 = (2π·w)/8 = πw/4 L2 = (2π·2w)/8 = πw/2 L3 = (2π·3w)/8 = 3πw/4 L4 = (2π·4w)/8 = πw. Differences in length between the neighboring wires are: L2 - L1 = (πw/2) - (πw/4) = πw/4 L3 - L2 = (3πw/4) - (πw/2) = πw/4 L4 - L3 = (πw) - (3πw/4) = πw/4. Specifically, if the inclination of the steps 15 of the wire length adjusting tool 14 is  (see FIG. 4) when a bending angle ε of the wires 11 at the curved portion 13 is 90°, the inclination of the steps of the wire length adjusting tool 14 is set to /2 as shown in FIG. 9 when the bending angle ε of the wires 11 is 45° as shown in FIG. 8. In general, the inclination of the steps 15 of the wire length adjusting tool 14 with respect to the bending angle ε of the wires 11 may be set at ( × ε/90°). In general the respective length of the n-th wire for a bending angle ε of the wires and for a distance between the wires 11 of w is given by the following equation (assuming that the wires are bent along an arc of a circumference): L n = 2π n w ε[°] 360° so that the length difference between adjacent wires generally is: Δ L = L n - L n -1 = 2π w ε[°] 360° In case the bent portions 13 of the wires 11 do not follow an arc of a circumference the above equations apply only as an approximation, however the invention is not limited thereto. The inclination  of the steps 15 may be constant for n sufficiently big, e.g. n≥4. As described above, only by performing a very easy action of pushing the wire length adjusting tool 14 having the steps 15 down with respect to the wires 11a to 11d after linearly arranging the wires 11a to lid, the wires 11a to 11d can be adjusted in length by being loosened by the lengths suited to forming the curved portion 13. Accordingly, the wires 11a to 11d can be arranged within a short period of time without requiring a work space and without being folded as in the third prior art. Since the wire aligning unit 22, the connector connecting units 24, the placing tables 28 of the circuit length adjusting units 25, and the wire arrangement tables 27 are detachable as individual units, wiring harnesses corresponding to a variety of wiring paths can be fabricated by changing their combination in various manners. For example, if a part 12a of the wiring harness where the film 12 is adhered is wished to be elongated as shown in FIG. 10, a plurality of wire arrangement tables 27 may be juxtaposed as indicated by Ar1 in FIG. 11 or a differently specified wire arrangement table (not shown) having a different length may be set. Further, if some of the plurality of wires 11 are branched from the rest and only the branched wires 11 are curved (as shown in FIG. 12), the connector connecting units 24, the circuit length adjusting units 25, the wire arrangement tables 27, etc. may be so rearranged as to conform to a design of the wiring path as shown in FIG. 13. Since the respective units are detachable as individual units, a degree of freedom in designing wiring harnesses can be enhanced by changing the combination of the units in various manners. In the case of a complicated wiring harness having three or more curved portions 13, the number of the circuit length adjusting units 25 may be increased so as to conform to the number of the curved portions 13. Further, if the distance between the curved portions 13 is changed in the case that there are a plurality of curved portions 13, the producing apparatus may be designed by changing, e.g. the distance between the connector connecting unit 24 and the circuit length adjusting unit 25. Although the wires 11 having being loosened by specified lengths to form the curved portions 13 are arranged on the same plane in FIG. 1, they may be arranged while being curved in a three-dimensional manner. Next a further preferred embodiment will be described with reference to FIG. 14. As can be seen from FIG. 14(B) the wire harness may have several branches being differently oriented e.g. by having different bent portions 13-1 and 13-2 having different angles (90° for the lower branch of FIG. 14(B) and 45° for the upper branch in FIG. 14(B)). These different bent portions 13-1 and 13-2 may be obtained by using the wire length adjusting tool 14 of FIG. 14(A). In this wire length adjusting tool 14 the steps or recesses 15 corresponding to the wires 11 (n=1..4) have an inclination of  (yielding an angle ε=90°), while the steps 15 corresponding to the wires 11 (n=5..8) have an inclination of /2 (yielding an angle ε=45°). The lengths of the wires n=1..4 are Ln=π n w/2 and for n=5..8 Ln= π n w/4. Thus the heights h3 and h6 of the steps corresponding to the wires n=3 and n=6, respectively are the same. As shown in FIG. 15 the wire harness may comprise also bent portions 13-1 and 13-2 having bendings in opposite directions, e.g. bent portion 13-1 being bent downward in FIG. 15 and bent portion 13-2 being bent upward in FIG. 15, wherein the angles ε-1 and ε-2 of the bent portions 13-1 and 13-2, respectively may be equal or not (ε-1=90° and ε-2=45° in the depicted embodiment). According to a further preferred embodiment (not shown) the wire length adjusting tool 14 may be arranged at an angle substantially different from 90° with respect to the longitudinal direction of the wires 11, so that the loosened portions of the wires 11 are not arranged on a line transverse to the direction, but shifted or spaced from each other with respect to the longitudinal direction of the wires. This embodiment allows for bent portions 13 of the wires 11 having different starting points, i.e. the bent portions 13 begin at longitudinally shifted positions with respect to each other, by using one single wire length adjusting tool 14. However, in case the bent portions 13 should start at equal positions the wire length adjusting tool 14 may be arranged substantially transverse (i.e. at 90°) with respect to the longitudinal direction of the wires 11 (or of the wire portions to be bent). After the production of the wiring harness is completed to the state of FIG. 1, substantially arcuate films (not shown) may be adhered to the curved portions 13a. LIST OF REFERENCE NUMERALS 11 (11a to 11d) Wire 12 Film 13 Curved Portion 14 wire length adjusting tool 15 Step 20 Wire Feeding Drum 21 Wire Feeder 22 Wire Aligning Unit 22a Groove 23 Connector 24 Connector Connecting Unit 25 Circuit Length Adjusting Unit 27 Wire Arrangement Table 28 Placing Table 29 Opening

Claims: A method for producing a wiring harness comprising: a first step of linearly arranging a plurality of wires (11) substantially in parallel with each other, a second step of setting different loosened lengths for the wires (11) of the specified wire group to compensate for length differences between adjacent arcs of the wires of the finished wiring harness, and a third step of fixing a plurality of wires (11), in particular by adhering the sheet member (12) over the plurality of wires (11), outside the loosened lengths thereof, characterized in that the different loosened lengths are set by bringing a loosened length adjusting means (14; 25) in close contact with the respective wires, wherein the loosened length adjusting means (25; 14) comprises a plurality of steps or recesses, extending at an angle different from 0° or 180°. A method according to claim 1, comprising a fourth step of establishing the desired configuration of the curved and linear portions of the wiring harness and adhering the protection film to the curved portion (13). A method according to claim 1 or 2, wherein: in the first step, the plurality of wires (11) are arranged to extend over an opening (29) which is provided in a predeter-mined or predeterminable position of a surface of a placing table means (28), and in the second step, the respective wires (11) are pushed into the opening (29) using the loosened length adjusting means (25). An apparatus for producing a wiring harness, in particular using the method of one or more of the claims 1 to 3, comprising: wire feeding means (21) for feeding a plurality of wires (11), a placing table means (28) comprising at least one table module, for linearly placing the plurality of wires (11), characterised by loosened length adjusting means (25; 14) provided with wire positioning means (15), comprising a plurality of steps or recesses, extending at an angle different from 0° or 180°, which set different loosened lengths of the respective wires (11) when brought into pressing contact with the wires (11) on or at the placing table means (24). An apparatus according to claim 4, wherein steps or recesses (15) have a specified inclination (), which is defined in accordance with the desired setting of the different loosened lengths of the respective wires (11). An apparatus according to claim 4 or 6, further comprising wire aligning means (22) for substantially parallelly aligning the plurality of wires (11) fed from the wire feeding means (21). An apparatus according to one or more of the claims 4 to 6, wherein at least one opening (29) is formed in a predetermined or predeterminable position of a surface of the placing table means (28), in particular in a placing table module thereof or between two adjacent placing table modules thereof, through or into which the loosened length adjusting means (14; 25) is movable to push the respective wires (11) after being brought into contact with the respective wire positioning means (15), in particular steps or recesses (15), thereof, wherein the opening (29) has preferably a width (a) along the longitudinal direction of the wires (11) such that the wires (11) are smoothly bent when they are pushed by the respective wire positioning means (15). An apparatus according to one or more of the claims 4 to 7, wherein the placing table means (28) further comprises a sheet member adhering table module (27) for adhering a sheet member to the linear portion of the plurality of wires (11) after the setting of the different loosened lengths and/or a protection film adhering table module for adhering a protection film to the curved portion (13) of the plurality of wires (11). An apparatus according to one or more of the claims 4 to 8, wherein the placing table means (28) further comprises: at least one connector connecting table module (24) for connecting at least one connector (23) with at least a part of the plurality of wires (11) after the setting of the different loosened lengths thereof by the loosened length adjusting means (14; 25). An apparatus according to one or more of the claims 4 to 9, wherein the portion (15r) of the loosened length adjusting means (14; 25) coming into contact with the wires (11) and/or the edges (28r) of the placing table means (28) is/are rounded off. An apparatus according to one or more of the claims 4 to 10, wherein the height hn of the n-th step (15) corresponding to the n-th wire of the plurality of wires (11) is approximately given by the following formula: h n ≈ L n 2 - a 2 = 1 2 L 2 n - a 2 wherein Ln is the length of the bent portion (13) of the n-th wire and a is the width of an opening (29) of the placing table means (28) along the longitudinal direction of the wires (11), wherein the length Ln is preferably given by the following approximative equation: L n ≈ 2π n w ε[°] 360° wherein ε is the bending angle by which the wires (11) are bent and w is the distance between adjacent wires (11). An apparatus according to claim 11, wherein the equations for the height hn of the n-th step (15) and/or for the length Ln of the n-th wire is/are adopted for n≥4. An apparatus according to one or more of the claims 4 to 12, wherein the wire positioning means (15), in particular the steps or recesses (15) are spaced from each other, preferably in the lateral direction of the loosened length adjusting means (14), depending upon the spacing(s) (w) of the wires (11). An apparatus according to one or more of the claims 4 to 13, wherein the wire positioning means (15) extends approximately transversely to the wires (11). An apparatus according to one or more of the claims 4 to 14, wherein the placing table means (24) is a placing table module.

Inventors: NAKAMURA ATSUSHI, SATO MASASHI, NAKAMURA, ATSUSHI, SATO, MASASHI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1997
Main classification: H01R43
IPC codes: H01R43