Production of circular seams on a workpiece

Abstract

For the production of circular seams with overlapped ends on a workpiece, a sewing machine driven in a controlled manner and provided with a marker for applying a mark, and a sensor for detecting the mark after marking the workpiece with a mark. The workpiece is sewn until the mark is effectively detected by the sensor which is disposed in a predetermined relationship to the marker, and thus initiates a control operation which initiates the end of the sewing operation in dependence upon a particular number of oversewn stitches. The mark may be applied and detected on the work material in one operating cycle. Thus, for example, circular workpiece openings may be sewn in such a way that the seam end is matched to the start of the seam in spite of different diameters of the work piece opening.

Dependencies are inferred from the claim text.