GB508556A - Improvements in or relating to hydraulic apparatus - Google Patents

Abstract

508,556. Hydraulic presses. RUSSELL, G. A. V., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Dec. 31, 1937, No. 36291. [Class 69 (ii)] In an hydraulically-operated extrusion, drawing and like press in which an auxiliary ram or rams 4 are provided for returning the main ram 2 after a working stroke, the auxiliary cylinder or cylinders 3 are juxtaposed end-toend with respect to the main cylinder 1 and the valves controlling the flow of hydraulic fluid to the cylinders are provided with remote control means and are housed in a block 9 connecting the ends of the cylinders and forming a distance piece between the main cylinder and the auxiliary cylinder or cylinders. Admission and exhaust valves 5, 6 respectively are provided in the block 9 for the main cylinder 1 and similar valves 7, 8 are provided for the auxiliary cylinder, and are connected by passages 48, 49, 50 to the supply main 55 and exhaust main 53. The stems 22, 23 of the four valves are pivoted to a rocker-member 10 which can be actuated manually if desired. As shown, however, the actuation is obtained through a servomotor system comprising a pair of plungers 30 beneath either of which fluid. may be admitted according to the position of a valve 45 operated by a solenoid 44 controlled by a lever 43 adapted to close either of two pairs of contacts la, 2a or 3a, 4a. A trip member 40 on the cross-head 39 of the main ram engages at the ends of the stroke and opens switches 41 or 42 so that the solenoid 44 becomes de-energized and the valve 45 closed. During movement of the rams, the fluid pressure in the servo-system acts on a piston 38 so as to keep closed a valve 36 in the connection 37 between the mains 53, 55. When one of the switches 41, 42 is opened, the valve 36 opens and short-circuits the pressure fluid. A valve 33 is provided in another connection between the mains 53, 55 for adjusting the speed of the press. Instead of a servomotor system, a suitable manually-operated linkage may be employed for actuating the control valves.