Patent GB-646496-A (GB)
Title: Improvements in or relating to tracer controlled metal cutting or like machines for copying
IPC: B23Q35/36
Filed: 1946-02-20
Abstract: 646,496. Copying-mechanism. TURCHAN, M., and WALKER, C. Feb. 20, 1946, No. 5383. Convention date, Nov. 18, 1940. [Class 83 (iii)] A tracer for a hydraulic copying-mechanism adapted to be employed in combination with a directional control mechanism and a number of cylinders for regulating the feed of a work-table in three mutually perpendicular directions comprises a spindle 12 projecting from a housing 14 having a number of fluid inlets and outlets with respect to which it is axially movable upon a substantially vertical thrust being applied thereto, and an adaptor 48 loosely journalling the spindle and capable of lateral translation on receipt of a lateral thrust, the adaptor and spindle actuating axially movable independent valve members directing fluid under pressure to the feed cylinders. The spindle 12 has a ball contact 31 with a valve member 18 provided with a stem 17 carrying a disc 27 in engagement with a cam 25 rotatable by a handle 26 for manual operation of the valve. The adaptor 48 is extended by members 33 and 32, the latter having an inclined annular surface co-operating with a complementary surface on a valve 42 through the intermediary of a ball-race 51. Thus lateral movement of the adaptor causes axial movement of the valve 42 and a valve 58 in threaded engagement with the latter. To prevent tilting of the adaptor a stabilizer mechanism comprising the member 32, ballraces 53 and a housing 54 is provided. Annular openings 19, 20, 59, 43 and 44 are formed in the valves which are biassed by springs 23 and 63. These openings co-operate with fluid inlets 29 and 66 and exhaust openings 28, 30, 60, 61, 45 and 47 in the housing from which fluid passes to the feed cylinders through conduits 19<SP>1</SP>, 20<SP>1</SP> and 431, 441. The vertical feed-cylinder has its lower end connected to the conduit 19<SP>1</SP> and its upper end connected to the conduit 20<SP>1</SP> while either the longitudinal or the transverse feedcylinder may be connected with the conduits 431, 441 through the directional control mechanism. A conduit 61<SP>1</SP> returns the exhaust from the cylinder not under tracer control to the tracer housing which it leaves through the opening 60 regulated by the valve 58. The spindle 12 provided with an adjustable tip 11 is supported by a ball-race 36 in the member 33 formed with an oil deflector 39 which together with a deflector 38 divert leaking oil to the lower end of the housing from which it is returned to a sump through a conduit 41<SP>1</SP>. When the piston 18 is displaced upwards by an axial thrust on the spindle from the pattern fluid flows via the openings 29, 20 and the conduit 20<SP>1</SP> to the vertical feed-cylinder causing the work-table to descend until the valve 18 terminates the flow. The exhaust returns via the conduit 19<SP>1</SP> and the openings 19, 28 to the fluid sump. Similarly, a downward displacement of the valve 18 will cause the work-table to ascend. Lateral thrusts on the adaptor from the pattern actuate the valve 42 to produce longitudinal or transverse feeding of the worktable according to the setting of the directional control mechanism, while the valve 58 regulates the exhaust from the cylinder not under tracer control, thus preventing damage to the work or tool if the reversal of direction of feed is late. The valves in a free condition adopt a slightly lower position than that shown in the Figure, allowing fluid to flow via the openings 29, 19, conduit 19<SP>1</SP> and the openings 46, 43, conduit 43<SP>1</SP>, until the pattern raises the valves to terminate the supply of fluid.