Construction having a wire layout used to form internal circuits of an electrical connection box

Abstract: To construct an upper casing, a lower casing and/or an insulation plate on which a wire is laid such that a starting end of the wire used to form internal circuits can be fixed and to facilitate wire laying. A wire W used to form internal circuits and laid on an upper casing, a lower casing and/or an insulation plate 1 is continuously laid by being inserted into a wire laying portion comprised of a wire laying groove 2 or pairs of guide projections 10 formed in or on the upper casing, the lower casing and/or the insulation plate 1. Cramping terminals are connected with the wire, and the wire is cut in desired positions to separate the circuits. A starting end retainer 5 is provided which is at an angle to the leading end of the wire laying portion at a wire layout starting position P. The wire is laid into the wire laying portion after its starting end is inserted into the starting end retainer.

Description: The present invention relates to a construction having a wire layout of internal circuits of an electrical connection box and to a wire laying method, and is particularly designed to, in a wiring circuit forming internal circuits of an electrical connection box by a wire and cramping terminals, facilitate wire laying by fixing a starting end of the wire to an upper casing, a lower casing and/or an insulation plate on which the wire forming the internal circuit is laid. In order to easily respond to a design change of internal circuits of an electrical connection box, it has been a practice to form internal circuits by wires and cramping terminals instead of by busbars formed by punching a conductive metal plate. The cramping terminals are mounted to connect the wires with external output terminals and also to connect the wires. In the case that the internal circuits are formed by a wire and cramping terminals, an upper casing, lower casing or insulation plate formed with a wire laying groove or wire laying guides along which the wire is laid is placed on an assembly board, and the wire is inserted between the wire laying guides or in the wire laying groove. In many cases, wire laying is performed as follows. A continuous strand of wire is automatically laid from a starting point of the wire layout to an end point thereof by a wire laying apparatus. Cramping terminals are mounted in desired positions to be connected with the wire, and the continuous strand of wire is cut in desired positions to separate circuits. When the wire is laid, it is necessary to fix the wire at the starting point by a certain method. A prior art method is such that, after the end of the wire is fixed by a chuck means disposed on the assembly board, the wire is laid on a casing or insulation plate. However, according to the above wire laying method, the end of the wire is extended from the wire layout starting point of the casing and/or an insulating plate on which the wire is laid to the chuck means, and is fixed. Therefore, after the completion of the wire laying, the wire extended to the chuck means has to be cut to be removed. Thus, the above prior art method requires an operation of fixing the end of the wire to the chuck means and an operation of cutting and removing the extended portion of the wire after the wire laying, and has a disadvantage of wasting the wire portion to be cut and removed. US-PS 4 684 765 discloses a method for laying a wire on a base plate in which an end of a wire to be laid is bent downwardly, inserted in a through-hole and held therein by a processor head having a cutter blade. However for providing a through-hole the base plate must have a higher thickness. A further problem resides in the necessity of a processor head having a cutter blade for inserting the wire into the through-hole, thus complicating the wire laying apparatus. US-A-5 156 557 discloses an electrical interconnection assembly comprising an insulating support body, a plurality of wire receiving terminals mounted on the insulating support body and a wire being inserted into respective wire receiving slots of the receiving terminals. The wires are cut into a plurality of wire pieces in such a manner as to form a predetermined wiring pattern being retained by a plurality of holding bosses provided on the insulating support body. However, no disclosure is given for the fixing of the wire at the starting point during the wire laying process. It is the object of the invention to provice a construction having a wire layout as well as a wire laying method enabling an easy wire laying in a wiring circuit forming internal circuits of an electrical connection box. This object is fulfilled by a construction having a wire layout according to claim 1 and by a wire laying method according to claim 6. Preferred embodiments are defined in the dependent subclaims. According to claim 1 the wire laying portion is formed by a wire laying groove and/or one or more pairs of guide projections formed in or on the wire laying plane or surface. The starting end retainer is substantially arranged on or comprised in the wire laying surface or in the plane containing the wire laying surface or plane, the starting end retainer preferably substantially not projecting outwardly or inwardly from the wire laying surface. Thus the wire is preferably fully arranged and/or hold on or at the wire laying surface. Preferably, the wire laying surface is arranged on an upper casing, a lower casing and/or an insulation plate. According to a preferred embodiment of the invention there is provided a layout construction of a wire used to form internal circuits of an electrical connection box in which a continuous strand of wire used to form the internal circuits is laid on an upper casing, a lower casing and/or an insulation plate by being inserted into a wire laying portion formed by a wire laying groove or pairs of guide projections formed in or on the upper casing, the lower casing or/and the insulation plate, cramping terminals are connected with the wire, and the wire is cut in desired positions to separate the circuits, comprising: a starting end retainer which is at an angle to the leading end of the wire laying portion at a wire layout starting position, wherein the wire is laid into the wire laying portion after inserting the starting end of the wire into the starting end retainer and bending it. The starting end retainer preferably comprises a wire laying groove or pairs of guide projections having substantially the same shape as the wire laying portion, and is at an angle to the leading end of the wire laying portion. Accordingly, if the wire is continuously laid while inserting its starting end into the starting end retainer and bending it at the leading end of the wire laying portion, the wire can be held at a bent point. As is clear from the above description, in the inventive layout construction of the wire used to form internal circuits of the electrical connection box, the leading end of the wire can be securely retained by continuously laying the wire into the wire laying portion after inserting the starting end of the wire into the starting end retainer formed at an angle to the leading end of the wire laying portion. Accordingly, unlike the prior art, it is not necessary to dispose, on an assembly board, a chuck means for fixing the wire end and to provide a superfluous wiring in order to fix the wire end with the chuck means. Further, an operation of fixing the wire end to the chuck means can be omitted. Therefore, wire laying can be performed with an improved operability. The starting end retainer may be at an acute angle to the leading end of the wire laying portion. Alternatively, the starting end retainer may comprise a first side portion which is at a substantially right or obtuse angle to the leading end of the wire laying portion and a second side portion which is at a substantially right or obtuse angle to the leading end of the first side portion, the second side portion being preferably longer than the first side portion. With the above constructions, the wire is not displaced at the leading end of the wire laying portion since it is securely retained by the starting end retainer. 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 an insulation plate on which a wire to form internal circuits of an electrical connection box according to a first embodiment of the invention is laid, FIG. 2 is a partial enlarged plan view of FIG. 1, FIG. 3 is a partial enlarged plan view of a layout construction of a wire used to form internal circuits according to a second embodiment, and FIG. 4 is a partial enlarged plan view of a layout construction of a wire used to form internal circuits according to a third embodiment. FIG. 1 shows a layout construction of a wire used to form internal circuits of an electrical connection box according to a first embodiment of the invention. Similar to the prior art, a continuous strand of wire W is laid from a starting point to an end point in a wire laying groove formed in an upper casing, a lower casing and/or an insulation groove in conformity with a wire layout pattern by an automatic wire laying apparatus. In this embodiment, a wire laying groove 2 is formed in an insulation plate 1, and the wire W is laid while being inserted into the groove 2. The insulation plate 1 is formed with a starting end retainer 5 for retaining a starting end of the wire W which is at an angle to the leading end of a wire laying portion at a wire layout starting position P of the wire laying groove 2. As shown in FIG. 2, the starting end retainer 5 is formed by a groove 6 similar to the wire laying groove 2, and is continuous with and at an acute angle to the wire laying groove 2 at the starting position P. In desired positions of the wire laying groove 2, there are formed terminal mount portions 3 for mounting cramping terminals to be connected with the wire W for the connection with external circuits. The wire W is laid on the insulation plate 1 after inserting the leading end of the wire W into the groove 6 of the starting end retainer 5 from its end portion 6a. When the wire W reaches the starting position P after being laid into the groove 6, a wire laying direction thereof is bent and the wire is continuously and automatically laid into the wire laying groove 2. If the wire W is continuously laid from the starting end retainer 5 to the wire laying groove 2 as described above while being bent at an acute angle, it can be securely retained at a bent point. In other words, the end of the wire inserted into the wire laying groove 2 is not displaced upon being pulled during the wire laying and, accordingly, the end of the wire can be securely held in the starting end retainer 5. Thus, unlike the prior art, it is not necessary to dispose, on an assembly board, a chuck means for fixing the wire end and to provide an unnecessary wire extended to the chuck means. Further, operability can be improved by eliminating the operation of fixing the wire end to the chuck means and the operation of cutting and removing the unnecessary portion of the wire after the wire laying. FIG. 3 shows a layout construction of a wire used to form internal circuits according to a second embodiment. A starting end retainer 5 formed in the insulation plate 1 includes a first side portion 7 formed by a groove which is at a right angle to the leading end of a wire laying groove 2 and a second side portion 8 which is at a right angle to the leading end of the first side portion 7. Accordingly, the retainer 5 is L-shaped when viewed from above. A length L2 of the second side portion 8 is longer than a length L1 of the first side portion 7 (L2 > L1). Particularly, it is preferable that the length L2 of the second side portion 8 shall be as long as possible, while the length L1 of the first side portion 7 is less important but shall preferably be kept small, in order to reduce the size of the wire arrangement. The wire W is laid on the insulation plate 1 of the second embodiment as follows. After being laid into the second side portion 8 from its leading end by an automatic wire laying apparatus, the wire W is bent and laid into the first side portion 7. The wire W is bent again and laid into the wire laying groove 2. The starting end retainer 5 according to the second embodiment has a lower retaining function than that of the retainer 5 according to the first embodiment because a bent portion between the wire laying groove 2 and the first side portion 7 and a bent portion between the first and second side portions 7 and 8 are at right angles, respectively. However, since the retainer 5 according to the second embodiment has two bent portions and the second side portion 8 at the leading end is longer than the first side portion 7 between the groove 2 and the second side portion 8, the starting end of the wire can be securely held in the first and second side portions 7 and 8 of the starting end retainer 5. It should be appreciated that the wire laying groove 2 and the first side portion 7, the first and second side portions 7 and 8 may be connected at obtuse angles, respectively. FIG. 4 shows a layout construction of a wire used to form internal circuits according to a third embodiment. This construction includes pairs of guide projections 10 projecting from an insulation plate 1 in specified positions along a layout pattern of a wire W. The wire W is held by being inserted between the pairs of guide projections 10. At a starting position P of the internal circuit, a bending projection 11 is provided at an inner side with respect to a bending direction, and retaining projections 12 for retaining a starting end of the wire W are provided in positions at a specified distance from the bending projection 11. A starting end retainer 5 similar to the first embodiment is formed by the projections 11, 12. The wire laying groove or guiding projections are formed in or on the insulation plate in the foregoing embodiments. However, it should be appreciated that provision of the starting end retainer is preferable even when the laying groove or guiding projections are formed in or on the upper casing or lower casing of the electrical connection box. LIST OF REFERENCE NUMERALS 1 Insulation Plate 2 Wire Laying Groove 5 Starting End Retainer P Wire Layout Starting Position W Wire

Claims: A construction having a wire (W) layout used to form internal circuits of an electrical connection box in which a continuous strand of wire used to form the internal circuits is laid on at least one wire laying surface (1) by being inserted into a wire laying portion (2; 10) formed in or on the wire laying surface (1), comprising: a starting end retainer (5 ; 11 ; 12) which is arranged at an angle to the leading end of the wire laying portion (2; 10) at a wire layout starting position (P), wherein terminal mount portions (3) for mounting cramping terminals to be connected with the wire (W) are formed in desired positions of the wire laying portion (2; 10) only, wherein the wire laying portion (2; 10) is formed by a wire laying groove (2) and/or one or more pairs or guide projections (10) formed in or on the wire laying plane (1), and wherein the starting end retainer (5) is substantially arranged on or comprised in the wire laying plane (1). A construction according to claim 1, wherein the starting end retainer (5) is at an acute angle to the leading end of the wire laying portion (2; 10). A construction according to claim 1, wherein the starting end retainer (5) comprises a first side portion (7) which is at a substantially right or obtuse angle to the leading end of the wire laying portion (2; 10) and a second side portion (8) which is at a substantially right or obtuse angle to the leading end of the first side portion (7). A construction according to claim 3, wherein the second side portion (8) is longer than the first side portion (7). A construction according to one or more of the preceding claims, wherein the wire laying surface is arranged on an upper casing, a lower casing and/or an insulation plate (1). A wire laying method of a wire (W) used to form a construction according to one or more of the preceding claims in which a continuous strand of wire used to form the internal circuits is laid on at least one wire laying surface (1) by being inserted into a wire laying portion (2; 10) formed in or on the wire laying surface (1), comprising the steps of: inserting the starting end of the wire (W) into a starting end retainer (5) being arranged at an angle to the leading end of the wire laying portion (2; 10) at a wire layout starting position (P), successively bending the wire (W) and laying it into the wire laying portion (2; 10), providing terminal mount portions (3) for mounting cramping terminals to be connected with the wire (W) are formed in desired positions of the wire laying portion (2; 10) only. A wire laying method according to claim 6, wherein the wire (W) is laid at an acute angle between the starting end retainer (5) and the leading end of the wire laying portion (2; 10). A wire laying method according to claim 6, wherein the wire (W) is laid in a first side portion (7) of the starting end retainer (5) which is at a substantially right or obtuse angle to the leading end of the wire laying portion (2; 10) and in a second side portion (8) which is at a substantially right or obtuse angle to the leading end of the first side portion (7).

Inventors: INOUE NORI, MATSUOKA HIDEO, OKA YOSHITO, ONIZUKA TAKAHIRO, SAKA YUUJI, INOUE, NORI, MATSUOKA, HIDEO, OKA, YOSHITO, ONIZUKA, TAKAHIRO, SAKA, YUUJI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1996
Main classification: H01R9
IPC codes: H01R9, H01R4, H02G3