PURPOSE: To obtain a safety controller for a sewing machine by measuring a signal interval between an upper position signal and a lower position signal from a needle position detector based on the pulse of an encoder, and prohibiting the rotation of a motor when a measured result is not within a prescribed value.
CONSTITUTION: When a power source is applied and a flip-flop 5 is set with a reset circuit 8 and the motor is rotated and an encoder signal EN is inputted, a counter circuit 1 starts the counting of the number of pulses of the encoder. The rotating speed of the motor is calculated with a rotating speed calculation circuit 2, and the signal interval time of a needle position signal is calculated with a time judging circuit 3. Meanwhile, when the upper position signal UDET is inputted to a flip-flop circuit 5a, the circuit 5a is set, and a flipflop circuit 5b is set with the output pulse of the time judging circuit 3, and the motor is continued to rotate. When no upper position signal UDET is inputted within prescribed time, no flip-flop circuit 5a is set, and the rotation of the motor is stopped with an abnormality signal UU. The lower position signal DDET is also measured similarly.
KANARI MASAYUKI
TOYODA EIJI
YAJIMA MAKOTO
HITACHI TAGA MOTOR KK
| JPS6121117A | 1986-01-29 | |||
| JPS62106798A | 1987-05-18 |
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