Wire length varying device in combination with apparatus for making electrical harnesses

Claim 1

A wire length varying device for use in combination with an apparatus for making electrical harnesses, wherein the apparatus includes a connector attaching device for affixing connectors to wire groups continuously supplied along a wire feed path; a wire length measuring and feeding device including a moving chuck for pulling the wire group already having the connector thereon for a distance corresponding to a desired length of an intended electrical harness; and a wire cutting means and an insulating covering stripping means, said wire cutting means and said insulating covering striping being operable independently of each other, the wire length varying device comprising: a tension pulley unit located on a wire supply path extending in a wire supplying device communicating with the connector attaching device through the wire feed path, the tension pulley unit including a plurality of pulleys carried to respective swinging arms mounted on a support means of the length varying device, each pulley being placed on the wire running therethrough such that the pulleys exert their weight on the respective wires so as to urge the same in a downward direction; a return preventive chuck unit for holding the individual wire groups, the return preventive chuck unit being located on the support means between the tension pulley unit and a wire selecting device receiving wires from the wire supplying device, the return preventive chuck unit includes first means for accomodating the individual wires, and second pneumatically operable means for selectively holding the individual wires; whereby upon an operation of the apparatus, the moving chuck pulls the wire group already having the connector thereon for a distance corresponding to a desired electrical harness, and is then caused to return in the counter-flow direction along the wire feed path, thereby allowing the wires therein to return under the additional urge provided by the tension pulleys, and in the course of returning by the first means in accordance with the distances over which the moving chuck is returned, thereby enabling the wires to slacken between the moving chuck and the connector attaching position, and causing the cutting means and the stripping means to work on the respective terminal ends of the wires, and finally causing the moving chuck to advance so as to stretch the wires from the slackened states.