Drive device for a sewing machine

摘要

A drive device for a sewing machine which varies the speed of the auxiliary motor. In a sewing machine drive device, the rotation of a clutch motor is transmitted through a pulley and an endless belt to the spindle of the sewing machine. The rotation of an auxiliary motor is transmitted through a driving sprocket, a timing belt and a driven sprocket and through the pulley to the spindle of the sewing machine. The drive device includes rotation varying means which varies the rotation of the auxiliary motor in response to the variation in diameter of the driving pulley of the clutch motor.