Abstract: In a method of operating a sewing machine for joining a jacket part (38) to a sleeve part (39), a sewing machine is employed, which has an operating and control unit. The desired stitch length and the length (la1 to ld1) of sections (a1 to d1) of the jacket part (38) and the length (la2 to ld2) of the sections (a2 to d2) of the sleeve part (39) that are allocated to the sections (a1 to d1) are fed into the operating and control unit. The required control pulses for the necessary feed drives are determined therefrom for each section (a1/a2 to d1/d2).

Abstract: An actuating device (54) for lifting the presser foot (53) of a sewing machine. A piston (14) having a piston rod (15) is supported on the bearing (13) which guides the presser foot support rod (18). The presser foot support rod (18) is biased against the sewing material by a spring (40). The piston (14) is surrounded by a cylinder (26). The piston (14) with the piston rod (15) and the cylinder (26) form a piston-cylinder drive for actuation by compressed air, to urge the piston rod (15) against the force of the spring (40) and thereby lift the presser foot (53) off of the sewing material. The actuating device (54) has two set screws (42, 45) which respectively control the spring force acting on the presser foot and the distance the presser foot is raised by the actuating device. Two embodiments are described.