Control system for frame shift in embroidering machine

摘要

An embroidery frame attached to an embroidering machine is shifted on a horizontal plane by means of a pair of pulse motors for changing relative position between a vertically reciprocating needle and a fabric supported within the embroidery frame. A phase sensor is arranged for continuously detecting a rotational phase of an upper drive shaft which governs a vertical position of the needle. The pulse motors are controlled such that a horizontal shift of the embroidery frame is prevented or discontinued in a particular circumstance for preventing breakage of the needle and/or damage of the fabric which would otherwise occur during the frame shift operation.