Sewing machine with an ultrasonic heater for folding back sewn edges

摘要

A sewing machine for sewing together two sheets of material and for separating and pressing their edges, includes folding means for separating and folding the edges and an ultrasonic generator for pressing and creasing them. An additional device includes a speed sensor for sensing a sewing speed of the sewing machine and a control device for controlling the ultrasonic generator to vary a strength of the ultrasonic wave according to the sensed sewing speed.