COIL SPRING FORMING DEVICE AND SPRING LENGTH MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a coil spring forming device with which a coil spring having a set spring length can be surely formed and a spring length measuring device which constitutes a part of the coil spring forming device.SOLUTION: A spring length is measured as an intermediate actually measured spring length in the middle of forming a coil spring 91 and also the feed rate of a wire rod 90 from the start of formation of the coil spring 91 to the measuring time of the intermediate actually measured spring length is measured as the intermediate feed rate of the wire rod. A portion of a difference between an intermediate reference spring length as a target spring length to the intermediate feed rate of the wire rod and the intermediate actually measured spring length is canceled during a period after the measuring time of the intermediate actually measured spring length until the feed rate of the wire rod 90 reaches a set feed rate and a pitch is changed in the middle of the formation by performing the position change of a pitch tool 14 so that the actual spring length of the whole coil spring 91 approaches the set spring length.