Sewing machine having improved corner stitch accuracy

Abstract

Abstract In a sewing machine, particularly an industrial sewing machine, with a needle which can be driven up and down by means of a needle bar, a feed dog for the forward transfer of the workpiece in co-ordination with the needle movement, an actual feed rate sensing device which supplies a corresponding electric signal and at least one sensor for detecting a workpiece edge, for the purpose of increasing the accuracy of the positioning of the corner stitch of a seam portion with acceptable constructional expenditure, a device is provided for displacing the longitudinal axis of the needle parallel to the sewing direction as a function of the actual feed rate sensing device on the one hand and the detection of a workpiece edge by the sensor on the other. Such a sewing machine is operated according to a method in which a seam is sewn with a predetermined speed, a predetermined stitch length and a predetermined distance from its end point to a material edge, the actual stitch length is determined and after a sensor has detected a workpiece edge a stitch length correction is brought about by displacing the needle axis, if the seam portion still to be sewn cannot be divided with substantially no residue by the actual feed length per stitch.

Inventors

• 👤 Jochen Fischer

Bibliographic Details