| 摘要 |
1,088.690. Sewing machines. SINGER CO. Sept. 30, 1966 [Oct. 5, 1965], No. 43685/66. Heading D1G. A two-thread chain stitch sewing machine comprises under thread-carrying means having loop-seizing and loop-shedding movements, and pneumatic means for cyclically forming a loop of under thread on said carrying means for penetration by the needle. As shown, a looper 21 has a nose portion 25 bounded by a bulge 37 and formed with an eye 26 communicating via an orifice 30, inclined at 45 degrees thereto, to one end of a conduit 27. The other end of the latter is bushed to pass the under thread 31, and also communicates with a branch connected to a source of compressed air. The arrangement is such that the needle thread loop 38, seized by the nose 25, is retained by the bulge 37 as the needle 15 rises, an under thread take-up then releasing thread which is blown into a horizontal loop 41 by air issuing from eye 26, loop 41 being penetrated by the needle in its next descent. In one modification, adapted to permit stitching during reverse feed, loop 41 is blown towards nose 25 during reverse feed by an independent jet of air. In a second modification, a groove extends from eye 30 towards the looper point, and the air pressure in conduit 27 is reduced during reverse feed, whereby loop 41 extends along said groove and is thereby positioned for penetration by the descending needle.
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