GB626176A - Improvements in precision grinding machines - Google Patents

Abstract

626,176. Grinding. CHURCHILL MACHINE TOOL CO., Ltd., and ASBRIDGE, G. H. May 19, 1947, No. 13367/47 and 5511/48. [Class 60] A precision grinding machine comprises a grinding wheel, an upper table, a tailstock and a headstock carried by said table, a lower table, a pivotal connection between the upper and lower tables at the grinding wheel side of the tables, a former, a slide carrying said former traversible longitudinally upon said lower table at the side of the latter opposite to that at which the grinding wheel is situated, and a part upon the underside of the upper table resting on said former so as to tilt the upper table as the slide is traversed. The machine comprises a headstock b and tailstock c carried by an upper table a mounted by pivots o, or by knife edges, on the lower table which can slide along the machine bed to move the work past the grinding wheel i. A member n secured to the underside of the upper table a cooperates with a former m secured on a slide k which can be moved longitudinally of the lower table j, so as to feed the work into the grinding wheel, by a piston and cylinder p, q supplied by a pump y through a distributing valve u operated in one direction by a spring w and in the other by a solenoid v. The tailstock centre f is slidably mounted, being urged towards work-engaging position by a spring 4 and being moved in the opposite direction by a piston and cylinder 5, 6 supplied by the pump y through a valve 8 operated by a handle 9 and a solenoid 10. To initiate an automatic cycle, the handle 9 is moved to the right. This connects cylinder 6 to exhaust, thus allowing the spring 4 to advance the tailstock centre f to pick up the work. Contact plate 13 carried by the piston 5 bridges contacts 14 to energize solenoid v, whereby valve u is moved, against spring w, to admit fluid to pipe r; piston p thus moves to the right, traversing the former m and tilting the table a to feed the work into the grinding wheel. At the end of the stroke of piston p, contacts 20 are closed by plate 19 operated by cam 18 on the piston rod; movement of contact plate 15 carried by the piston p opens contacts 16 and closes contacts 17. Closing of contacts 17 energizes relay 24 which closes normally open switches 25, 26, switch 25 is in series with the solenoid 10 and switch 26 is connected across contacts 17. Closing of contacts 20 energizes dwell relay 27 which after a predetermined interval opens switch 28 to de-energize solenoid v; this causes return of piston p to its left hand position; the consequent closure of contacts 16 causes solenoid 10 to be energized (although contacts 17 are now open, relay 24 is maintained in circuit by switch 26), moving valve 8 to the left thus admitting fluid to cylinder 6 to withdraw tailstock centre f for the work. This opens contacts 14 to de-energize the electrical circuit.