Patent GB-1140216-A (GB)
Title: Improvements in hydraulic or pneumatic reciprocating piston drive systems
Inventor: PENTHER HERMANN
IPC: F01B17/02
Filed: 1966-05-19
Abstract: 1,140,216. Hydraulic reciprocating motors; valve gear; compressors; intensifiers. STAHLUND APPARATEBAU HANS LEFFER G.m.b.H. May 19, 1966 [May 20, 1965], No. 22239/66. Headings F1A, F1M, F1N and F1P. A hydraulic or pneumatic motor, e.g. incorporated in a pressure booster 26, 27, as shown, has one four-way, 36, Fig. 1, or two three-way, 37, 38, Fig. 9, reversing valves which are hydraulically or pneumatically actuated by the motor piston 21 at the end of each stroke. The four-way reversing valve 36 of the Fig. 1 embodiment, has stepped faces F 1 , F 2  at each end, Fig.6, in chambers 50, 51 connected to pressure source 39, Fig. 1, by passages 52, 53 in the valve member. Chambers 50, 51 are also connected to lowpressure by restricted passages 46, 47. In the position shown in Fig. 6, the valve is supplying pressure to the right-hand side of piston 21, the valve being held in its right-hand position by the differential action of both surfaces F 1 , F 2  on the left being subjected to pressure, while only surface F 1  on the right is subjected to pressure, surface F 2  on the right sealingly engaging an O-ring 49 and being connected to low-pressure by passage 47. When piston 21 reaches the end of its leftward stroke, it operates a valve 63 to connect chamber 50 to low-pressure. The high-pressure in chamber 51 is then effective on the right-hand surface F 1  to commence moving the valve member slowly to the left, while O-ring 49 expands to its uncompressed state, thereby producing a delay in reversal. When O-ring 49 has fully expanded, righthand surface F 2  becomes exposed to the pressure in chamber 51 and the valve member is moved rapidly to the left, reversing the connections to the motor piston 21. When the valve member reaches its left-hand position it is cushioned by O-ring 48, which also seals left-hand surface F 2  from chamber 50. When piston 21 commences its right-ward stroke, it releases valve 63 to restore pressure to chamber 50. In the embodiments of Figs. 2 to 5 (not shown), valves 63, 64 are replaced by valving grooves on booster pistons 26, 27 acting to connect chamber 50 and 51 to lowpressure, or the low-pressure side of the motor piston 21. In Fig. 8 (not shown), valve 36 has its passages 46, 47 connected to ports in the valve housing which are controlled by the valve member to connect passages 46, 47 to high or low-pressure. The three-way reversing valves 37, 38 of the Fig. 9 embodiment each comprise a valve member 92, Fig. 16, with a projection 92a having a face in which a passage 97 opens, the passage 97 being connected to the pressure supply and being closed by abutment with the valve housing, except for a restricted groove across the face 92a, when the valve member 92 is in its left-hand position. The valve member is held in its lefthand position by the differential action of surface F 1  being connected to low-pressure through passages 91, 93 and surface F 1  -F 2  being connected to pressure. Movement of the valve member from left to right, to change over the connections to one end of the motor cylinder, is effected by supplying pressure to passage 91, or by closing passage 91 so that the leakage across face 92a from passage 97 builds up pressure in chamber 96. Movement from right to left is effected by connecting passage 91 to low-pressure. In Fig. 9, the passages 91 of valves 37 and 38 are maintained at different pressures by connections 98, 99 to opposite ends of the motor cylinder. Reversal of valve 38 is effected at the end of the right-ward stroke of piston 21 by the piston operating a valve 101 to connect chamber 96 of valve 38 to low-pressure, the valve member then moving to connect the right-hand end of the motor cylinder to pressure. This pressure is transmitted through connection 98 and passages 93 and 91 to valve 37 to effect its reversal to connect the left-hand end of the motor cylinder to lowpressure. In Figs. 10 to 15 (not shown), alternative methods of applying high or low-pressure pulses to reverse valves 37 and 38 comprise slide valves and piston and cylinder devices actuated by the motor piston, and slide valve means and piston and cylinder devices formed by the booster pistons 26, 27.