| 摘要 |
PROBLEM TO BE SOLVED: To provide an upward/downward feeding sewing machine, with which sewing is enabled with an optimal thread tension at all the time even when a contraction quantity is changed in a series of sewing parts. SOLUTION: In the upward/downward feeding sewing machine, which is provided with an upward feeding means for feeding upper fabric and a downward feeding means for feeding lower fabric, for controlling the quantity of contraction to be applied to an object to be sewn by changing a difference in the feeding quantities of both the feeding means, the sewing machine is provided with a thread conditioning device to be driven by an electric driving means to change the thread tension and a control means for controlling the thread conditioning device to change the thread tension corresponding to the contraction quantity. A setting means is provided for setting the setting value of the thread tension corresponding to the contraction quantity and the control means controls the thread conditioning device corresponding to the contraction quantity so that the thread tension of the setting value set by the setting means can be provided.
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