Transport device for sewing machines

摘要

According to the invention, by means of a force sensor which is known per se, for example a piezoceramic element, the momentary presser foot force is determined during the sewing work, the measured value is compared in an evaluation circuit with 2 adjustable control variables, and, depending on the result of the comparison, an actuator, for example a pneumatic pressure transducer influenced by a direct-current motor, is activated. The presser foot force is regulated via a working cylinder by means of a change in pressure. <IMAGE>