Patent GB-626618-A (GB)
Title: Hydraulic grinding machine
IPC: B24B47/06
Filed: 1945-08-01
Abstract: 626,618. Hydraulically-operated grinding machine. NORTON CO. Aug. 1, 1945, No. 19817. Convention date, Nov. 16, 1944. [Class 60] A grinding machine having a table which carries the work piece and is reciprocated by a fluid piston and cylinder under the control of a table actuated reversing valve; a transversely movable slide which carries a rotatable grinding wheel and is fed by a vane type fluid motor under the control of a fluid actuated control valve; and a pilot valve which is actuated in timed relation with said reversing valve to actuate said control valve during table reversals to impart oscillatory movements to said motor and thereby cause an infeeding movement of the grinding wheel at the ends of the table stroke, is characterized in that the control valve is arranged to impart to said fluid motor a complete oscillation in both directions for each movement in either direction of the control valve. The work 27 is mounted between centres on headstock 30 and tailstock 31 carried by work table 11 which is power traversed by piston 16 in cylinder 15; the distributing valve 20 comprises a shuttle member slidably mounted on a stem the ends of which are provided with pilot valves; the valve stem is moved by dogs carried by the table 11, thus moving the shuttle member to shut off exhaust from the cylinder 15. The movement of the valve stem renders the pilot valve operative so that the shuttle member is then moved hydraulically to its reverse position. Specification 602209 is referred to. An adjustable throttle valve 275 brakes the movement of the shuttle member whereby a dwell of the table 11 at reversal is obtained. A stop-start valve 252 in its " off " position connects the ends of the cylinder 15 together to permit hand traverse of the work table; in its "on"  position, this connection is interrupted, and fluid is admitted to cylinder 200 to disengage a clutch in the hand traverse drive. In its " off" position the valve 252 blocks off the exhaust line from the distributing valve 20 to prevent hydraulic traverse of the work table; in its " on position the valve 252 throttles this exhaust, which passes to a main control valve 160. In its " off" position the valve 160 blocks this exhaust, but in its " on " position connects this exhaust to reservoir; movement of the valve 160 to its "on" position causes a valve 60 to be operated hydraulically whereby fluid is admitted to rear of cylinder 57 causing a piston 58 to move the grinding wheel carriage to its operative position; simultaneously fluid is admitted to cylinder 209 to close the electrical circuit for a motor 32 rotating the work. Simultaneously with movement of the traverse control valve 20 by the dogs on the work table a pilot valve 290 is moved to cause movement of distributing valve 95 whereby at each end of the stroke of the work table the vane of motor 85 is moved counterclockwise and then returned clockwise to its original position; the drive from the vane motor 85 to the feed screw 50 includes a freewheel so that the counterclockwise movement of the vane puts on feed, the clockwise movement being ineffective. The vane motor drives a gear 115 mounted in a pivoted casing which can, by handle 137, be rocked to engage gear115 with gear 77 on the hand feeding gear which may be as described in Specification 6784/01, [Class 60]. The main control valve 160 is actuated, through cams, by rotation of the hand feed wheel so as to initiate an automatic cycle.