| 摘要 |
An apparatus for stitching material in a sewing machine having a throat plate having a stitch tongue, a stitch forming instrumentality for forming an overedge stitch having a needle, an upper looper, and a lower looper. The apparatus has first plates for applying tension to a first thread passing to the upper looper, second plates for applying tension to a second thread passing to the needle, third plates for applying tension to a third thread passing to the lower looper, fourth plates for selectively applying tension to the first thread, fifth plates for selectively applying tension to the second thread, and sixth plates for selectively applying tension to the third thread. The apparatus has a pair of cylinders for actuating the fourth and sixth tension plates to release tension on the first and third threads while applying tension by the fifth tension plates during sewing on a fabric, a cylinder for subsequently actuating the fifth tension plates to release tension on the second thread while applying tension on the fourth and six tension plates to form a loose chain of stitches on the stitch tongue, and a blower for blowing the chain of stitches off the stitch tongue.
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