CONTROLLER FOR SEWING MACHINE

摘要

PURPOSE:To improve the workability for any of high and low speed sewing machines by selecting the constant of a calculator in accordance with selecting means. CONSTITUTION:A tachometer generator 2 outputs a pulse signal train through a waveform shaper 3 in the state that a sewing machine 1 is rotated. This pulse signal train is divided in frequency in response to the set amount from a speed setter 5 from a frequency divider 4. A counter 6 counts a clock pulse from a variable frequency oscillator 7 over one period of a frequency-divided pulse PD, latched to a latch 8, the actually measured period TP is outputted to a subtractor 9, thereby controlling the drive unit 12 of the motor. The ratio of the set speed of each stage for the depression of a pedal is varied by selecting the constant of a calculation equation of a calculator 9 by selecting means 11, thereby obtaining the prescribed speed curve.