| 摘要 |
A thread feeding apparatus for a sewing machine which has a simplified mechanism for accuracy of manufacturing and improved durability so as to accommodate high speed sewing. The thread feeding apparatus for the sewing machine has upstream grippers for respectively gripping an upper looper thread and a lower looper thread, closed by a stitch forming device at the time of the stitch forming and opened at the time of the cloth feeding, downstream grippers for gripping the respective threads introduced from the respective upstream grippers, opened at the time of the stitch forming so that the respective threads are pulled by the stitch forming device and closed at the time of cloth feeding, and reciprocators which are respectively driven in a synchronous manner with a left needle, a right needle, an upper looper and a lower looper, at the time of cloth feeding. The reciprocators shift the respective threads in thread paths extending between the respective opened upstream grippers and the respective closed downstream grippers to pull off a thread quantity necessary for forming a stitch and, at the time of stitch forming, release the respective threads.
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