A METHOD AND APPARATUS FOR THE PRODUCTION OF WIRING LOOMS

Abstract: In the method, lengths of wire (9) are drawn from wire supplies (10) and cut, each end of each cut wire being stripped of insulation and terminated, and the cut wire then being laid along a predetermined path defined by guide pins (4a) on a loom board (3). The wire lengths are then bound together and removed from the board. The wire (9) is handled by a mechanical gripper (7) which moves and is actuated under preprogrammed electronic control. The apparatus comprises a loom board (3) or the means by which such a loom board can be made, an auto­ matic manipulator having a controlled gripper (7) to draw wire (9) from a preselected supply (10), a cutter (8) to cut the wire, a wire stripper and insulative sleeve applica­ tor (16) and a terminal supply and crimper (17), both accessible to the gripper which can then lay the terminated wire lengths along predetermined paths on the loom board (3), and a tape binder (25) which binds the laid wires together to form the required wiring loom (27).

Description: This invention relates to a method and apparatus for the production of wiring looms. As used herein, the term wiring loom means a bundle of individually insulated electrical wires, bound or otherwise held together, to be installed in equipment having spaced electrical components to provide the required electrical connections between such components. A major use of such wiring looms is in the manufacture of powered vehicles such as automobiles or industrial trucks. Whether powered electrically, or by means of an internal combustion engine, a large number of electrical components require interconnection, and for this purpose one or more such wiring looms are disposed in appropriate channels or recesses, or are otherwise fixed in the vehicle, and the ends of the wires, appropriately precut to the required length and terminated, are connected to the components. The wires usually have different colour insulation to facilitate the correct connection by the fitter of the wires to the components. The looms commonly include wires of a number of different lengths, arranged with various branches projecting from a main central trunk. The production of such looms involves complex procedure, and involves the use of a loom board comprising a board carrying a multiplicity of pins fixed in and projecting from one side of the board, these pins being arranged to define predetermined guide paths along which the wires are laid prior to being bound together. Various attempts have been made to render the production of wiring looms or harnesses at least partially automatic. These attempts are illustrated by United States Specification No. 3186077 (which proposes the use of an array of pins on a base board and the fixing of the ends of wires to selected pins by means of a clip pusher), No. 3699630 (which proposes the use of a base board with predisposed termination sites) and No. 3842496 (which proposes the use of base boards having predisposed termination sites and guide pegs in predetermined locations). A method which is not of general applicability is illustrated by United States Patent No. 4126935, which relates to the production of twisted pairs and proposes the use of mass termination blocks for the wires. A form board into which the pins for defining guide paths are screwed or hammered is shown in United States Specification No. 3346020. A looming board is known from The Western Electric Engineer, April 1975, pages 68 to 77, "Software Controlled Forming of Local Cables", in which a wire feed head is movable in two dimensions over the board for wire laying under computer control. The head is also movable vertically so as in a preliminary operation to enable the drilling of the board, also under computer control, to prepare it to receive a multiplicity of guide pins. Although the board can be used to form a multiplicity of different looms simultaneously at different locations on it, it does not permit the pins to be removed and replaced automatically so as to enable different looms to be formed in sequence. According to the invention there is provided a method of producing a multiplicity of wiring looms each constituted by a bundle of individually insulated electrical wires of predetermined lengths, the method being defined in the appended claim 1. The invention also provides apparatus for making a wiring loom, the apparatus being defined in the appended claim 3. An embodiment of the invention will now be described by way of example with reference to the accompanying drawings. Figure 1 is a schematic side elevational illustration of apparatus for use in the production of wire looms; Figures 2 to 12 are schematic illustrations showing successive steps in the operation of the apparatus of Figure 1 to produce a wire loom. With reference to Figure 1, apparatus 1 for the production of wire looms is located generally above a conveyor 2 which conveys the completed looms away from the apparatus. The apparatus comprises a rectangular loom board 3 adapted to receive and hold guide pins to project upwardly from a flat upper surface of the board to define predetermined paths for the wires of the loom. A guide pin feeder 4 is disposed over the loom board 3 and is adapted to present the pins 4a (see Figures 2 to 14) to be gripped and removed by means of a mechanical gripper, such as one having a pair of relatively displaceable jaw members and a pneumatic actuator arranged to control the relative movement of the jaw members. The pins so supplied are double-ended to avoid the necessity for the feeder to distinguish between differently shaped pin ends and to select one such end for presentation to the gripper. The construction of the loom board is such as to permit the pins to be temporarily fixed at any point on the board and to be readily ejected when desired. The board is preferably pivotally mounted so as to be inverted, thereby to facilitate removal of wiring looms therefrom, and deposition of the looms upon the conveyor. A stop 5 and indexing unit 6 serve to locate the loom board properly with respect to the other components of the apparatus. The gripper 7 is part of an automatic manipulator, and is carried at the end of an articulated arm, indicated schematically, at 30 by a broken line. The movements of the arm and actuation of the gripper 7 are under electronic control from a central control unit 31 of the manipulator, the sequence of operational movements being predetermined and preprogrammed in a memory, or upon a suitable recording medium such as punched or magnetic tape, or floppy disc which bears coded commands for conversion into electrical signals which can be processed in the electronic control to actuate the gripper as required. An automatic manipulator which is particularly suitable for this purpose is the "Puma" robot made and sold by Unimation Inc., of Danbury, Connecticut, U.S.A. Disposed within the range of movement of the gripper is an assembly of electrically operable wire cutters 8, one such cutter being provided for each respective one of a plurality of wires 9. Each wire 9 is supplied from a respective reel 10 and extends via one or more guide pulleys 11 through a wire drive assembly 12 comprising a drive capstan 13 and a pinch roller 14, and through a guide 15 to the respective cutter. Also accessible to the gripper is an assembly of wire stripper and sleeve dispenser units 16 and wire terminal supply and crimp units 17. Each unit 16 is capable of removing from an end of a wire properly presented thereto by the gripper, a predetermined length of insulation from the conductive core, and of placing over the bared wire an insulating sleeve. Units 17 are each capable of applying to the bared wire and, when properly presented thereto by the gripper, and after stripping and sleeve placement by a unit 16, an appropriate terminal element, such as a spade terminal. The unit 17 crimps the terminal onto bared wire end, and then moves the insulating sleeve over the crimped part of the terminal. The terminals may be supplied to the units 17 from a reel 19 in the form of a continuous strip 18 from which the individual terminals are cut. The construction and operation of the cutters, stripper and insulator units, and terminal supply and crimp units form no part of the present invention and accordingly has not been described in detail herein. The sequence of operation of the apparatus of Figure 1 in the production of a batch of wire looms will now be described. The first part of the sequence is the setting up of the required loom board to define the correct wire paths for the particular type of loom to be produced. To achieve this, the gripper operates under the pre-programmed electronic control to remove pins from the guide pin feeder 4, one at a time, and to place them on the board at predetermined positions, as illustrated in Figure 2, the board being adapted to receive and releasably hold the pins with a portion of each pin projecting from the board. As mentioned before, the pins define the paths for the wires of the looms these paths consisting generally of a central trunk path along which a part of most, if not all of the wires, will extend, and a number of branch paths, projecting laterally from the trunk paths, along which the end portions of the wires will extend. The required wire reels 10 are then loaded on reel stands (not shown) in a manner and sequence as dictated by the programme controlling the electronic control, and the leading ends of the wire fed round the guide pulleys 11, through the wire drive assemblies 12 and guides 15. The gripper 7 then grips the wire projecting from a guide 15, leaving a projecting end portion 20, and the drive assembly 12 for that wire is actuated, as shown in Figure 3. A predetermined length of the wire is advanced by means of the drive capstan 13, and simultaneously the wire end portion 20 is presented to a stripper and sleeve dispenser unit 16, and then to a terminal supply and crimp unit 17, which operate upon the wire end as described hereinbefore. Figures 4 and 5 illustrate these two operations. The capstan 13 stops, and the gripper 7 then releases the now terminated wire end, and returns to take hold of the wire adjacent and just beyond the wire cutter 8, relative to the guide 15, as shown in Figure 6. The cutter 8 is then actuated by a signal from the electronic control, and the end portion 21 now held by the gripper is presented to the stripper and sleeve dispenser unit 16 and to the terminal supply and crimp unit 17, as illustrated in Figures 7 and 8. The gripper 7 then lays the cut and terminated length of wire 28 along its predetermined path by anchoring the end just terminated between a pair of pins at the end of the board and threading the wire between the pins 4a defining that path, as illustrated in Figure 9. The above described procedure of wire stripping, terminating, cutting and positioning is repeated for each wire length of the loom, different colour coded wire, wire lengths and terminal types being employed as dictated by the operational programme. When all of the wire lengths have been laid on the loom board, an adhesive tape dispenser 25 operates to apply, at each of a number of specific points on the main trunk and branches of the loom, a length of tape drawn from a reel 26 to encircle and bind together the wire, as illustrated in Figure 10. The loom board 3 is then inverted, as shown in Figure 11 to drop the bound loom 27 onto the conveyor 2 which may convey the loom to a braiding machine (not shown) which applies a protective braiding to the entire loom. After ejecting any loom which is not to be the last of the batch, the board is reinverted so that the pins again project upwardly, and another similar loom of wires is assembled on the board, bound and ejected. After ejecting the last loom of the batch, the pins 4a are released from the board and jettisoned, as shown in Figure 12, while the board is still inverted and consequently fall onto the conveyor 2 whence they may be collected and returned to the guide pin feeder 4. The loom board, after reinversion, is then ready to receive guide pins defining the wire paths of a different loom batch to be produced subsequently.

Claims: 1. A method of producing a multiplicity of wiring looms each constituted by a bundle of individually insulated electrical wires of predetermined lengths, the method employing a board which is adapted to receive and hold temporarily a multiplicity of guide pins such that the pins project from a substantially flat surface and the method employing an automatic manipulator which moves and is actuated in accordance with a predetermined programme of commands, the method comprising the steps of (i) causing the manipulator (7) to remove guide pins from a supply (4) thereof and to place them at predetermined positions on said board (3) so as to define a multiplicity of predetermined paths for the wires of the loom, (ii) causing the manipulator (7) to grip a selected wire projecting from a supply thereof, (iii) feeding a predetermined length (28) of the selected wire to the manipulator, (iv) cutting the wire to sever the length thereof, (v) causing the manipulator (7) to anchor the length of wire at one end and to lay the length of wire between guide pins (4a) along a respective one of the predetermined paths, repeating the steps (ii) to (v) in respect of a multiplicity of lengths of wire so as to assemble a bundle of wires, (vi) fastening the lengths of wire together while they are located on the board (vii) removing the loom (27) constituted by said bundle by inverting said board so that the bundle falls away from the board, repeating the steps (ii) to (vi) for each loom to be produced and (viii) finally releasing and jettisoning the pins from the board so as to be ready to receive guide pins defining the predetermined wire paths of a different loom batch to be produced subsequently. 2. A method according to claim 1 in which a terminal fitting is applied to one end of the length of wire before the wire is cut, another terminal fitting being applied to the end resulting from the cutting. 3. Apparatus for making a wire loom, characterised by the combination of a multiplicity of guide pins (4 a ), a substantially flat loom board (3) adapted to receive and hold temporarily said guide pins, a feeder (10-14) arranged to present a plurality of wires (9) each of which can be drawn from a supply, an automatic manipulator (7) which is arranged to move and be actuated in accordance with a predetermined programme of commands, the manipulator being programmed to remove said guide pins from a supply thereof and to place the pins at predetermined positions on the board so that the pins project from the surface of the board and define a plurality of predetermined paths for the wires of the loom, and the manipulator also being programmed, on reception of each of a multiplicity of lengths of said wire, to anchor one end of each length and to lay the length between guide pins along a respective one of the paths, means for fastening the lengths of wire together to form a bundle while the lengths are on the board, means for inverting the board so as to remove the bundle of fastened lengths from the board, and means for releasing and settisoning the pins from the board. 4. Apparatus according to claim 3 in which the pins (4 a ) are double-ended so that either end can be received and held by the board. 5. Apparatus according to either of claims 3 or 7, including means for stripping and applying a terminal fitting to each end of each length of wire.

Inventors: GIBBONS, RALPH DAVID
Applicants: BRITISH AEROSPACE PUBLIC LIMITED COMPANY
Application year: 1979
Main classification: H01B13
IPC codes: H01R43, H01B13