| 摘要 |
1,108,824. Ratchet gearing. R. BLOHM. 24 Jan., 1967 [10 Feb., 1966], No. 3614/67. Heading F2Q. A stepping device for the downfeed of a grinding wheel in a grinding machine comprises a ratchet wheel 10, secured on a shaft 12 which preferably carries a worm gear meshing an output worm-wheel (not shown), engageable by a pawl 14 pivoted at 15 to a pawl carrier 13 pivoted about the shaft 12, the carrier being rocked by an electromagnet 16 on the driving stroke and returned by a spring 21. A fixed ramp 30 engages a tail 28 of the pawl to hold the tang 27 of the pawl away from the ratchet wheel when the device is inoperative. A screw 31 limits the stroke of the magnet armature 18 so that the ratchet wheel is advanced one tooth pitch at each energization of the magnet 16. A plunger 24 allows manual actuation of the device. Electronic apparatus may control the energizing pulses to the magnet 16. |
