GB374918A - Improvements in or relating to grinding or abrading machines - Google Patents

Abstract

374,918. Grinding. JUNGE, C., 28, Kaiserallee, and WERNER AKT.-GES., F., both in Marienfelde, Berlin. March 9, 1931, No. 7294. [Class 60.] Driving and feed devices; gauges. - The grinding-wheel of a machine for repetition work is returned a f t e r each operation by a pawl and ratchet device so that its surface irrespective of wear, is at a con s t a n t distance from that of the finished article The feed-screw is operated by hand, or by rotation of a shaft 11 by a ratchet wheel 10, pawl 9, and links 7, 8 from a crank disc 6, which at given intervals is rotated through 360‹. Ratchet wheels 14, 15 keyed to the shaft 11 are engaged by pawls 17, 16 on a freely mounted disc 18. During the feed the pawl 16 abuts against a stop 21 thereby stopping the disc 18, but the pawl is lifted by a cam surface 21a from engagement with the ratchet teeth to permit further feeding of the tool to compensate for its wear, until, when the predetermined size is reached, a controlling finger resting on the work stops the disc 6. An adjustable stop 22 is positioned to engage the pawl 17 on the return movement of the disc 18 and ratchet wheels, such movement thus being a constant determined by the stops 21, 22. A device for causing the feed to vary progressively from a coarse feed to a series of constant fine feeds comprises a follower 29 engaging a cam surface on the disc 18, and varying the number of ratchet teeth exposed on the disc 10 by a shutter 24. A modification is described in which this device is omitted. In a further modification the disengageable pawl and ratchet device 16, 15 is replaced by yieldable friction discs.