| 摘要 |
PURPOSE:To cut off a power source automatically when an operator has left it ON carelessly and thereby avoid wasting power, by a method wherein time is counted after the stopping of the driving of the sewing machine is detected, and when the counted value has reached a predetermined value, a stopping signal is generated to cut off the power source. CONSTITUTION:When a sewing operation is finished and the stepping-in on a pedal is released, a lever 1 is returned, a microswich 6 is turnred OFF and a timer circuit TM starts to count time. In the case of interrupting the sewing operation with a microswitch SW2 left ON, when the counted value reaches a preset value, the timer circuit TM generates an abnormal signal, whereby a transistor TR is turned ON to energize a relay R2, and a contact R21 is changed over from NC side to NO side so as to de-energize a relay R1. The supply of power to a motor M is stopped due to the turning-OFF of contacts R11-R13, and the voltages on the primary and secondary sides of a transformer T are reduced to zero, and after a capacitor C is discharged, the relay R2 is also de- energized. Then, the machine can be started by depressing a reset switch SW1. |
