| 摘要 |
PROBLEM TO BE SOLVED: To provide a sewing machine which is equipped with a fabric feeding mechanism using a feed motor comprising a stepping motor as a driving source and prevents the feed motor from rotating easily if external force affects it while the power is off. SOLUTION: A controlling device 10 controls to drive the X-axis feed motor 11, comprising the five-phase stepping motor which moves a movable frame (fabric) in the X-axis direction, through a motor driving circuit 24. A short- circuit line 25 connecting coils of a plurality of phases (between a second phase and a fourth phase) of the X-axis feed motor 11 is provided, and a normally close type relay (a relay contact) 26 is inserted in the short-circuit line 25. The motor driving circuit 24 keeps the relay 26 open during excitation of the coils, and makes the relay 26 closed to cause a short between the coils when the coils are not excited, including a case when the power of the sewing machine is off. A switch 9 for release of a brake to cancel a connection between the coils by a manual operation is provided. |
