Patent ID: 8100069

Claim:
A control device of a sewing machine comprising: a pressing member which is detachably attached to a lower end of a pressing bar of the sewing machine; a pressing frame which is supported by the pressing member so as to be movable in a cloth feeding direction of a workpiece and which holds the workpiece; feed detecting means for detecting a position or a feeding amount of the pressing frame in the cloth feeding direction with respect to the pressing member; a feed dog which feeds the workpiece in the cloth feeding direction every stitch in association with the pressing frame; a feeding motor which sets a cloth feeding amount of the feed dog; a storing portion which stores, in every stitch, an error between a target position or a target feeding amount of the pressing frame in the cloth feeding direction and a detected position or a detected feeding amount obtained by the feed detecting means; and control means operable, in every stitch, to determine a correction value from the errors in a plurality of stitches which are stored immediately before, and to control the feeding motor to drive with the cloth feeding amount corrected by the correction value.