| 摘要 |
PROBLEM TO BE SOLVED: To provide a back stitch device for a sewing machine for preventing a finger or elbow of an operator from slipping from an operation part of a back stitch lever to perform false operation even when the operation part of the back stitch lever is not carefully operated. SOLUTION: A sewing machine 2 and its back stitch device 1 include: a cloth feed mechanism 20 for operating a feed dog 11; a switch shaft 6a for freely switching a feed direction of the feed dog 11 backward and forward; a back stitch lever 5 for operating the switch shaft 6a; two link members 7, 8 joined to the back stitch lever 5, the switch shaft 6a, and a sewing machine frame 2a. The two link members 7 and 8 are disposed in parallel, while the back stitch lever 5, the two link members 7, 8, the switch shaft 6a, and a support shaft 9b form a four-bar mechanism of a parallelogram having joint holes 7a, 7b, 8a, and 8b of the two link members as turning pairs. COPYRIGHT: (C)2010,JPO&INPIT
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