Patent GB-578881-A (GB)
Title: Improvements in or relating to cross feed mechanism for grinding machines
IPC: B24B47/20
Filed: 1943-08-03
Abstract: 578,881. Grinding - machines. CINCINNATI MILLING MACHINE CO. Aug. 3, 1943, No. 12510. Convention date, June 26, 1942: [Class 60] A cross-feed mechanism for grinding-machines is provided with hand-operated and automatic actuating means and with a stop device for sizing the work, means also being provided whereby wear of the grinding-wheel may be compensated for. The mechanism is described as applied to the feed of the grinding-wheel support 11 through rack and pinion and worm gearing 18 ... 21, the shaft 17 of the worm 18 being driven through gearing 15, 16 by a gear 14, secured to a sleeve 22 rotatable in a fixed part 25 of the machine and terminating in an internal gear 26. Rotatable in the sleeve is a shaft 27 provided with an eccentric part 30 and a concentric extension 31, on which is rotatable an internal gear 32 ; the part 31 also has keyed thereon a hand wheel 34. The part 30 has thereon two connected gears 36, 37 of slightly different diameter meshing respectively with the gears 26, 32, and arranged so that one rotation of the part 30 will move the gears 26, 32 relatively to one another by onehundredth of a revolution. On the gear 32 is secured a plate 39 having therein ten notches 41, with which may be engaged a spring-pressed plunger 43 carried by a handle 44 on the wheel 34; with the parts thus arranged, when the plunger engages a notch, rotation of the wheel 34 rotates the gear 14 to the same extent. A graduated dial in the form of a ring 47 7 surrounds the gear 32, and may be locked thereto by a two-armed lever 48 pivoted to the dial, spring-pressed inwardly at one end and at the other end having teeth which may be brought into engagement with the toothed periphery 51 of the gear 32 by a screw 53 carried by the dial; the dial has thereon graduation marks each corresponding to, .0005" infeed, a zero mark being, provided on a fixed part of the machine. In order that work may be ground to a desired size, a stop 57 is slidably mounted in a fixed part of the machine, for engagement by a stop plate 58 secured to the dial 47, whereby feed is stopped positively at the desired point, and in order to compensate for wear of the grinding- wheel the wheel 34 is rotated with the plunger 43 withdrawn from a notch 41 ; the gear 14 is held stationary by the friction of the parts and the gear 32 is driven, thus moving the dial 47 and stop plate 58 slightly so that a slight additional rotation of the wheel 34 is necessary when the feed again is in operation. To prevent collision between the stop plate and the stop when the wheel 34 is rotated reversely to withdraw the.grinding-wheel from the work, the stop and stop plate have bevelled ends 60, 61 respectively, whereby on contact, the stop is slid axially; the stop also is movable manually by a lever 71 pivoted in a fixed socket and passing through a head 73 on the stop 57, which may be held in operative or inoperative positions by a spring-pressed ball and notches in the stop. Automatic operation. of the feed at each reversal of the work-table is effected by fluid pressure means enclosed in a housing 105, and comprising a piston 76 having thereon rack teeth 77 engaging teeth on a lever 78, which carries a pair of spring-pressed pawls 79, adapted to engage a ratchet-wheel 81 connected through gearing to a gear 83 freely rotatable on the sleeve 22. The operation of the automatic feed also is stopped at the desired point by the stop mechanism described above, and for this purpose a stop valve 85 is provided, the plunger 86 of which has at one end a contact button 87 for, engagement by a button .88 on the gear 83, the shank 89 of the button 88 passing through the gear and engaging a slot 90 in the stop plate 58 ; this connects positively the gear, stop plate and the dial 47. The valve 85 is connected in a control line for the piston 75 comprising branches 91, 92 and connects these alternatively to fluid supply and exhaust; an enlarged spool 96 on the plunger 86 also is acted on, after passing mid-position, by fluid to complete the shifting of the plunger. The pawls 79 normally are out of contact with the ratchet teeth so that hand operation may take place ; alternatively, one of the gears may be slidable axially on its shaft out of or into mesh.with the gear 83.