| 摘要 |
In an embroidery sewing machine having a lower thread winding device, when the non-lower thread state of the bobbin is detected by a residual amount sensor, a sewing machine motor is stopped to detect and recognize the size of the embroidering frame of an embroidering device by means of a frame size sensor and the embroidering frame is moved corresponding to the size to position the corner of a workpiece held in the embroidering frame under a needle. Then, an extra sewing operation is carried out over the corner to consume the lower thread remaining in the bobbin, and subsequently, it is decided whether or not the embroidering frame is moved by a distance required for completely extracting the lower thread from the bobbin (an amount of the residual lower thread is detected when the non-thread state is detected by the residual amount sensor). If the distance is insufficient, the destination of the embroidering frame is updated to repeat the extra sewing operation over the next corner of the workpiece S, thereby completely extracting the lower thread from the bobbin.
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