| 摘要 |
PROBLEM TO BE SOLVED: To enhance the stability during sewing by controlling the speed of the spindle to be suitable for each of various operations. SOLUTION: This sewing machine has a middle holder, a spindle which moves the middle holder up and down along the up-and-down direction of the sewing needle, and a spindle-driving device. This sewing machine also has an adjusting shaft for adjusting the height of the middle holder at its bottom dead point from the needle plate, a spindle-driving device for driving the adjusting shaft, and a conveying device for conveying an item to be sewed in a perpendicular direction against the vertical movement direction of the sewing needle. In addition, this sewing machine has a memory to record a conveying length of the item to be sewed, a first spindle speed determined on the basis of the conveying length, a fluctuation of the middle holder, and a second spindle speed determined on the basis of this fluctuation, and a control device for controlling the spindle-driving apparatus, the spindle-driving device and the conveying device. The controlling device controls the spindle-driving device by the lower principal speed between the first and the second spindle speeds. COPYRIGHT: (C)2007,JPO&INPIT
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