JPS6411590A - Cloth hem following sewing machine - Google Patents

Abstract

PURPOSE: To form a straight stitch line with a final sewing position in copy sewing as a base point by forming stitches copying a cloth edge, operating an operation member, inhibiting the updating of the stored contents of a storage means by a sewing inhibition means and supplying the needle position control signal of a previous time to an actuator. CONSTITUTION: In the case that a cloth edge position fluctuates, since detection signals from a cloth detector 54 do not match with reference signals from a variable resistor 112, error signals from a comparator 114 are not zero anymore and they are converted to digital signals in an A/D converter 116 and supplied to an adder 118. During the operation of a sewing machine, since a timing pulse from a timing pulse generator 88 is supplied through an OR circuit 122 to the adder 118, the adder 118 adds the digital signals from a latch 120 and the digital signals from the A/D converter 116 corresponding to the input of the timing pulse. The positions of a needle bar base and a sewing needle are changed so as to match the detection signals from the cloth detector 54 with the reference signals from the variable resistor 112.