Sewing machine with a stitch counter and correction unit
AssigneeDurkoppwerke GmbH
InventorHeinz Goldbeck
Life of this patent
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Abstract
A sewing machine with a presettable counter for sewing a predetermined number of stitches to the end of a stitch seam. According to the invention the counter is provided with a correction unit responsive to at least two sectors of a rotary machine member, each revolution of which corresponds to the sewing of a stitch of normal length. A sensor is responsive to the different sectors and, upon detection of one of these sectors, produces a signal which an evaluating unit can pass to a count resetting unit to set back the stitch counter by one stitch unit. As a consequence, the overrun or underrun of the stitch seam is at most one half of the normal length of a stitch.
Claims5
In a sewing machine having a sewing machine arm and mechanism including a cyclically operating moving member for producing a succession of stitches forming a stitch seam, means for detecting the trailing edge of a workpiece part to be sewn with said seam, and a presettable stitch counter responsive to said detecting means for terminating operation of the sewing machine after the sewing of a number of stitches corresponding to that set in said counter, the improvement which comprises a correcting unit for controlling the count registered in said counter, said unit comprising sensing means responsive to at least two different sensing sectors of said member, evaluating means connected to said sensing means and generating an output when said sensing means responds to one of said sectors, and adjusting means connected to said evaluating means and responsive thereto to reset the count in said counter in accordance with the output of said evaluating means.
Dependencies are inferred from the claim text.