Patent GB-626856-A (GB)
Title: Cylindrical grinding machine
IPC: B24B5/04
Filed: 1946-05-01
Abstract: 626,856. Hydraulically-operated grinding-machines. NORTON CO. May 1, 1946, No. 13145. Convention date, June 11, 1945. [Class 60] [Also in Group XXIX] A cylindrical grinding machine comprises a base, a longitudinally reciprocable work supporting table, a rotatable grinding wheel carried by a transversely movable slide, means including a fluid motor for infeeding said slide, control means for said motor to cause the motor to execute a continuous unidirectional motion to produce a uniform uninterrupted infeeding movement of the slide during a complete plunge-cut grinding operation, control means for said motor to produce an intermittent infeed of the grinding wheel during table reversal for a transverse grinding operation. and selector means whereby either of said control means may be rendered operative while the other remains inoperative. General machine details. The work 27 is mounted between centres carried in a headstock 30 'and footstock 31 mounted on a longitudinally movable work table 11; the work is rotated by a motor 32. The grinding wheel 42 is mounted on a transversely movable carriage 38 and is rotated by a motor 43. Grinding wheel feed.- The wheel carriage 38 is fed by means of a screw 50. A manually operable feed wheel 70, provided with micrometer adjusting mechanism as described in Specification 6784/01, rotates a feed gear 73 which through gearing rotates a sleeve 53 in which is splined the end of the feed screw 50. Power feeding mechanism comprises a rotary vane type motor 85 which through gearing rotates a gear 113 mounted in a casing 114 which can be swung from inoperative position to (1) a position in which the gear 113 is still free from the feed gear 73, but a stop on the casing 114 is in the path of a lug carried by the feed wheel, or to (2) a position in which the gear 113 engages the feed gear 73. To bring the grinding wheel rapidly up to the work, the feed screw 50 is moved axially by a piston 58. The piston 122 58 is controlled by a valve 60; the vane motor 85 is controlled by a valve 95. Plunge-cut grinding.-To initiate an automatic cycle, the valve 60 is moved to the left. This admits fluid to (1) move the piston 58 to the left causing rapid approach of the grinding wheel to the work, (2) actuate a piston 170 to switch on the workrotating motor, (3) actuate a piston 235 opening a valve 231 to start the flow of coolant and (4) move the valve 95 to the right, so that the vane of the motor 85 commences its infeeding motion. The rate of feed is controlled by a needle valve 260 through which the exhaust from the motor 85 passes. A shuttle valve 315 is connected in parallel with the rate valve 260; the fluid which moves the valve 95 to the right also moves the shuttle valve member 316 down, so that an additional amount of fluid can exhaust from the motor 85 thus giving more rapid movement during the initial feed, for the purpose of taking up backlash in the feed screw and/or for shoulder grinding. The rate of movement of the valve member 316 is controlled by needle valve 321; fluid passing through the shuttle valve 315 is controlled by a needle valve 319. Fluid is also admitted to a timing device 300 so as to move a piston 301 to the left, the rate of movement being controlled by a needle valve 307; after a predetermined interval of time, the movement of the piston 301 uncovers a port and allows fluid to pass to pipe 308 and thence to move a valve 280 to the left, which causes movement of the valve 60 to the right, so reversing the feed motor 85 and moving the piston 58 to the right to remove the grinding wheel from the work; the work motor is automatically switched off, the flow of coolant automatically stopped, and the timing piston 301 and shuttle valve member 316 are automatically returned to their initial positions. Work table traverse.-The work table 11 is traversed by piston 16 under control of a valve 20, which is actuated by dogs on the table to give automatic reversal. A dwell valve 250 is provided. A stop-start valve 210 is provided which in one position connects the two ends of the traversing cylinder together to permit adjustment by manual traverse means operated by a handwheel 14, and in another position controls the exhaust from the traversing cylinder. Traverse grinding intermittent feed. - By rotation of a selector valve 258a, 258b, 258c the apparatus is set to give feed at each reversal of the work table. A valve 273 is operated by the table reversing lever, whereby at each reversal of the table, a shuttle valve 270 is moved from one end position to the other, thus permitting a certain amount of fluid to exhaust from the vane motor through a needle valve 266. The rate of movement of the shuttle member 270 is controlled by needle valves 280, 283. The operation is initiated by moving to the left the valve 210 which in addition to. starting the work rotation, opening the coolant valve, and initiating the feed and traverse, also automatically unclutches the hand traverse wheel.