| 摘要 |
PROBLEM TO BE SOLVED: To change the vertical movement stroke of a thread take-up lever into the predetermined vertical movement stroke, preferably, to adjust a thread take-up lever stroke in response to a sewing condition during a sewing operation. SOLUTION: A sewing machine includes a stepping motor 28 for adopting a thread take-up shaft 18 as an eccentric shaft, rotating and driving the thread take-up shaft 18, and then changing an eccentric shaft center position. The vertical movement stroke of the thread take-up lever 16 is made to be changeable. The stepping motor 28 is controlled in driving, so as to change the vertical movement stroke of the thread take-up lever 16 during the sewing operation, based on the data table of the vertical movement strokes of the thread take-up lever 16 which are respectively set according to the thickness of a processed fabric, the rotary speed of an upper shaft 2, sewing data, the number of stitches from the start of sewing, and the number of stitches after the end of sewing. COPYRIGHT: (C)2009,JPO&INPIT
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