METHOD OF SENSING LEADOUT HOLE OF WIRE TAKEUP DRUM

PURPOSE:To make sensing of the position of leadout hole by obtaining simultaneously the output signals of two sensors, which sense the leadout hole provided in a rotary takeup drum, and allowing thereafter the sensors to stop outputting the signals. CONSTITUTION:No.1 and No.2 sensors 5, 6 are arranged with a space l2 between them which is smaller than the opening size l1 of a leadout hole 3 in its circumferential direction, where the leadout hole is provided in a flange 2 of a rotary takeup drum 1 supported on a table. These sensors 5, 6 are of a type of photosensor or magnetic sensor, which senses the reflected beams originating in a light emitting element using a light receiving element. When the takeup drum 1 is rotated at a low speed, the leadout hole 3 passes the sensible range of No.1 and No.2 sensors 5, 6 to give signals. When the two sensors 5, 6 are actuated at the same time and thereafter signal from the sensor 5 stops, it is judged that the leadout hole 3 is sensed. Now rotation of the thakup drum 1 is stopped.