Workpiece holder setting for an automatic sewing machine

摘要

The determine accurately the zero position of a needle, in an automatic sewing machine, the workpiece holder (10) is initially moved from a suitable start point into a zero setting with sensor monitoring. The workpiece holder (10) is shifted from the sensor-monitored zero setting into a second zero setting where the angular settings of the linkages (7,8) of the co-ordinate drive (9) are checked against a gauge. On a deviation, the linkages (7,8) are moved by sliding until they match the gauge setting, and the necessary correction value is stored in the memory (26) of the electronic control (6). The workpiece holder (10) is then moved into a set needle zero position, and the sewing machine and the workpiece holder are moved in relation to each other until the needle (5) of the sewing machine (4) can be inserted into the positioner opening (12) of the workpiece holder (10). The exact needle zero position is given taking into account the co-ordinates of the gauge and th e needle zero points and the stored (26) correction values, to be used for subsequent sewing and embroidery operations. Also claimed is an appts. where the monitored zero setting of the workpiece holder (10) has sensors (23,24) fixed at the automatic sewing machine assembly (1). Preferably to determine the corrected needle zero point, only the workpiece holder (10) is moved by the operation of the drives (16,17) until the needle (5) of the sewing machine (4) can be inserted into the positioner opening (12) of the workpiece holder (10). This correction value is passed to the memory (26) of the electronic control (6), to be used on subsequent sewing and embroidery work. When an accessory is used, carried by the workpiece holder (10), its positioning is determined by the holder (10) movement, and the matching correction value is passed to the memory (26) to be used when the accessory is started up. Step motors (16,17) are used as the drives for the workpiece holder (10).