Patent GB-615631-A (GB)
Title: Surface grinding machine
IPC: B24B7/00
Filed: 1945-09-06
Abstract: 615,631. Grinding and polishing. NORTON CO. Sept. 6, 1945, No. 22943. Convention date, Nov. 1, 1944. [Class 60] A grinding machine has two opposed grinding surfaces adapted successively to engage the two sides of a workpiece disposed between said surfaces for grinding opposed plane faces on said workpiece, said grinding surfaces being surfaces on a pair of grinding wheels carried in spaced relationship by a spindle rotatably mounted on a slide, feeding means being provided for said slide to move either of said wheel surfaces towards or away from said workpiece, and independently adjustable stop means to limit the movement of said slide in either direction precisely to locate said wheel surfaces for grinding said opposed plane faces. The grinding wheels 16, 17 are mounted on spindle 15 carried by slide 14 vertically movable on the machine frame by piston 71 in cylinder 70 under control of a valve 77 operated by handle 82; the weight of the slide and parts carried thereby is counterbalanced by piston 76 in cylinder 75, supplied with pressure fluid through relief valve 164; a second relief valve 167 and non-return valve 169 for making-up on the upward stroke are also provided. For positioning the upper grinding wheel 16 in desired operative position a threaded portion of the piston rod carries a threaded sleeve 200 which by abutting against the upper end of the cylinder limits the downward motion ; the sleeve is adjustable by worm gear 201 and worm 202 operated by hand wheel 203 with provision for micrometer adjustment, as e.g. in Specification 6784/01, [Class 60]. A similar arrangement is provided for limiting the upward movement so as to position the lower grinding wheel 17 in desired operative position. The work is carried by a slide 12 movable transversely on a longitudinally movable slide 11. The longitudinal movement of slide 11 is effected by piston 21 in cylinder 20 under control of a valve 25; transverse movement of slide 12 is effected by piston 53 in cylinder 52 under control of a valve 57. On manual actuation of valve 25 to initiate a cycle, the slide 11 moves to the right, thus traversing the work under the grinding wheel; at the end of this stroke, a dog 69 on the slide. 11 actuates valve 57 causing the slide 12 to move transversely rearwardly, thus traversing the work under the grinding wheel, the exhaust being controlled by needle valve 163 so that movement is slow; at the end of this stroke, a dog 215 on the slide 12 actuates valve 25 causing the slide 11 to move to the left, thus traversing the work under the grinding wheel; at the end of this stroke dog 69a on the slide 11 actuates the valve 57 causing the slide 12 to move transversely forwardly, thus returning the work to its original position relative to the grinding wheel; at the end of this stroke dog 216 on the transverse slide 12 actuates the valve 25 causing the slide 11 to move to the right, starting a fresh cycle. The dog 216 can be moved to inoperative position, so that the action stops after one complete cycle. Dogs 151, 152 on the slide 11 actuate a valve 148 which in conjunction with throttle valves 157, 159 control the exhaust from the valve 25 so that the slide 11 is slowed down towards the end of its approach movement to the right, and commences its return stroke slowly. A stop and start valve 40 controlled by handle 47 serves to render the hydraulic actuation inoperative. The slides 11, 12 can be moved, for adjustment purposes; by hand wheels 170, 180, operating rack-andpinion mechanism through clutches which are held inoperative by fluid pressure when the valve 40 is in the "go" position, but which are rendered operative by springs when the fluid pressure is cut off by movement of the valve 40 to " stop " position, in which it connects the ends of the cylinder 20 together and also the ends of the cylinder 70 together, so as to permit movement of the slides by hand. For indexing the work, an indexing plate 90 is provided having a retaining pawl 92 and an indexing pawl 93 operated by piston 96 in cylinder 95 under control of a valve 100 manually operated by lever 105, a plate 226 carried by the slide 11 co-operating with a part 227 on the valve lever so as to prevent actuation of the indexing mechanism except when the slide 11 is in its extreme left-hand, i.e. retracted position. A one-shot lubricant pump 285 is provided to force lubricant through pipes 292, 293 and 294 to the wheel slide and work table ways. The pump can be actuated manually by a knob 286 and is also actuated automatically, every time the work-indexing mechanism operates, by a piston 290 in a cylinder 289 to which fluid is supplied simultaneously with the supply to the work-indexing cylinder 95. The machine is provided with wheel truing mechanism as described in Specification 615,632.