A wire length varying device in combination with apparatus for making electrical harnesses

Claim 1

A wire length varying device for use in combination with apparatus for making electrical harnesses, wherein the apparatus includes a connector attaching device (11) for affixing connectors (3) to wire groups continuously supplied along a wire feed path (W); a wire length measuring and feeding device (13) including a moving chuck (45) for pulling a wire group already having a connector thereon for a distance corresponding to a desired length of an intended electrical harness; and a wire cutting means (33, 34) and an insulating covering stripping means (35, 36), the last-mentioned two means being operable independently of each other, characterised in that the wire length varying device comprises: a tension pulley unit (51) located on a wire supply path (W) extending in a wire supplying device (10) communicating with the connector attaching device (11) through the wire feed path; the tension pulley unit (51) including a plurality of pulleys (54) carried on respective swinging arms (51), each pulley (54) being placed on the wire running therethrough such that the pulleys (54) exert their weight on the respective wires so as to bias them downwardly; and a return preventive chuck unit (52) for holding the wire groups individually, c the chuck unit (52) being located between the tension pulley unit (51) and the wire supplying device (10); the return preventive unit (52) including a first means (57, 58) for accommodating the wires (21 to 26) individually, and a second means (59, 60) pneumatically operable for holding the individual wires selectively; whereby, upon operation of the apparatus, the moving chuck (45) pulls the wire group (2A) already having a connector (3) thereon for a distance (L) corresponding to a desired electrical harness length, and is then caused to return in the counter-flow direction along the wire feed path (W), thereby allowing the wires therein to return under the additional urge provided by the tension pulleys (54), and in the course of returning the wires are selectively prevented from further returning by the first means (57, 58) in accordance with distances over which the moving chuck .(45) is returned, thereby enabling the wires to slacken between the moving chuck (45) and the connector attaching position, and causing the cutting means (33, 34) and the stripping means (35, 36) to work on the respective ends of the wires, and finally causing the moving chuck (45) to advance so as to stretch the wires from the slackened states.