STITCH-SHAPE CHANGING MECHANISM OF ZIGZAG STITCHING MACHINE Russian patent published in 1994 - IPC

FIELD: zigzag stitching machines. SUBSTANCE: stitch-shape changing mechanism is arranged in stitching machine head and has axle with a set of cam disks connected with machine main shaft, pusher kinematically connected with frame of needle guide and mounted on nut-mandrel for motion along axis of cam disks. Nut-mandrel is installed on lead screw with multistart thread. Lead screw is connected with Maltese-cross movement whose crank with pins is installed on axle of handle for changing over types of stitch, and Maltese cross is installed on lead screw end. Shifting of pusher from one cam disk to another one is effected over U-shaped trajectory. In this case, pusher is shifted across the axis of cam disks under the action of cam. Pusher is installed on nut-mandrel for its displacement along axis of lead screw to control the position of pusher relative to cam disks. Mechanism also includes indicator of stitch type having drive and driven gears. Drive gear is rigidly installed on lead screw end, and the driven gear is freely fitted on bushing of changing over handle and connected by means of rack-and-gear drive with movable indicator. Turning of Maltese cross is fixed with the aid of spring retainer interacting with shaped recesses on rim of crank of Maltese cross movement and arched closing cams. EFFECT: improved convenience in use and higher accuracy in adjustment of machine. 2 cl, 9 dwg