PURPOSE: To enable a worker to check at any time the rotary speed of a grinding wheel, by generating AC voltage in a generating part through rotation of a main shaft and measuring the period of an AC signal of the voltage in a detecting part, in the case of a pneumatic type grinder.
CONSTITUTION: A rotor 2 and a main shaft 3 are arranged inside a motor case 1, and rotation of the rotor 2 is transmitted to the main shaft 3 by bevel gears 4, 5. A speed detecting device is constituted by a generating part 11 and a detecting prt 12. The generating part 11 comprises a disc-shaped magnet 13 secured to an upper end of the main shaft 3, a pair of stators provided oppositely facing to each other in the periphery of the magnet 13 and a coiled iron core 15. Accordingly, the magnet 13, also rotating in accordance with rotation of the main shaft 3, causes AC voltage to be generated in a coil of the coiled iron core 15, and a period of the AC voltage corresponds to a rotary speed of the main shaft 3. The rotary speed of the main shaft 3 can be detected by measuring the period of this AC signal.
SUGIMOTO TADAKATSU
NISHIKAWA KAZUNARI
IKOMA HISANARI
ERUDA KK
| JPS5950666B2 | 1984-12-10 | |||
| JPS55160858A | 1980-12-15 |