Abstract: A sewing machine provided with guide means and ironing means having an ultrasonic heating means. The guide means folds back the free margins of an upper and lower fabric pieces, and the folded margins are pressed or ironed by the ultrasonic heating means. The ultrasonic heating means includes an ultrasonic horn and an anvil relatively movable toward and away from each other. A thickness detector is provided for detecting a combined thickness of the upper and lower fabric pieces, and control means is also provided for controlling one of the heating energy of the ultrasonic heating means and a distance between the horn and the anvil in response to the detected thickness.

Abstract: 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.