| 摘要 |
PURPOSE:To constitute an apparatus enabling the display of an absolute position by graduations for detecting a position, by adding a mechanism for detecting the number of rotations to an auxiliary rotor having a different diameter cooperated with a main rotor for detecting the position of a rotary disc. CONSTITUTION:A plurality (eight in the drawing) of graduations 11 are provided to a main rotor 10 which is, in turn, rotated around a shaft 13 and a sensor 20 performs detection along with reference graduations 12. An auxiliary rotor 30 having a different diameter and the main rotor 10 are formed as toothed pulleys and cooperated with a toothed belt 15. The auxiliary rotor 30 is rotated around a shaft 31 and a sensor 35 detects reference graduations 32. Every when the graduations 11 are sensed by a graduations sensing part 21, a signal (a) is outputted to allow a counter 23 to step and, when the reference graduations 12 are sensed by a reference graduations sensing part 22, a signal (b) is outputted to allow a counter 24 to step to reset the counter 23. The sensor 35 issues output (c) at every one rotation of the auxiliary rotor 30 to allow a counter 36 to count said output (c). By this simple structure, a position signal is subjected to digital processing in the same way as an absolute type one to enable the detection of an absolute position. |
