MACCHINA PER CUCIRE CON DISPOSITIVO PER L'OTTENIMENTO DI CUCITURE SAGOMATE

A sewing machine for sewing shaped seams comprises equipment for exactly positioning an end stitch. By means of two edge sensing sensors provided one after the other in the feed direction, a pulse generator coupled to the main shaft, and a microprocessor, the difference between the desired feed length of the workpiece and the actual feed length thereof is determined. A microprocessor controls a step motor for adjusting a stitch setting device, the adjustment being a function of the difference between the desired and actual feed lengths of the workpiece and of the angular position of the main shaft at the instant of response of the second sensor. In this way, the length in excess of the last stitch which, without a correction, would extend beyond the predetermined end point, is uniformly distributed among the last stitches of the seam, while at the same time taking into account slippage between the feed dog and the workpiece.