Circuit arrangement of an automatic stitch-length and stitch-number adjusting device

摘要

The solution according to the invention serves for ensuring a constant distance from the last needle stitch of a sewing machine to a reference edge (for example, the edge of the sewing material) independently of the operator. According to the invention, a sewing machine possesses a main-shaft position sensor G1, a stitch-number sensor G2, a sewing-material edge recognition sensor G3 and a counting and evaluation control. When the sewing-material edge is reached, the main-shaft position is classified into at least four regions according to its crank angle. A control of the stitch-length adjusting device and/or a variation of the preselected stitch number takes place according to this classification. <IMAGE>