GB929717A - Improvements in fluid pressure operated valves - Google Patents

Abstract

929,717. Valves. PARKER-HANNIFIN CORPORATION. Feb. 26, 1962, No. 7454/62. Class 135. A main valve 12, Fig. 1, controlling the supply and exhaust of fluid to a motor, is actuated by a pilot valve 14. In the embodiment shown, the main valve comprises two valves 26a, 26b having valve closures 28 connected to pistons 50. An inlet 21 and exhaust 22 communicate by chambers 48 and ports 46 with chambers 42 on one side of the valve members, while chambers 34 on the other side are connected to the two sides of the motor. The inlet 21 is also connected by passages 66, 100, 101, non-return valve 144 and passage 92 to a bore 105 the pilot valve 14. A passage 142 leads from downstream of the non-return valve 144 to an accumulator chamber 140 which maintains a supply of fluid pressure sufficient to actuate the main valve irrespective of a fall in pressure at the inlet. Passages 90, 88, 96 lead from the pilot valve to chambers 70 above the pistons 50 while passages 94, 98, 96 and 67 connect the pilot valve to exhaust 22. The pilot valve member 106 is actuated by an electromagnet 16 and is loaded by a spring 118. With the pilot valve in the position shown, the inlet 21 is connected via passage 66 to a chamber 40 of valve 26b and fluid flows to one side of the motor through port 38 and chamber 34, the fluid pressure acting on the valve member 28 of valve 26b to hold the valve in the position shown. Fluid pressure in chamber 42 of valve 26a acts on piston 50 of valve 26a to hold it in the position shown and the other side of the motor is connected to exhaust 22 to chamber 34 of valve 26a, port 38, chamber 40, passageway 67 and chamber 48. During this stage the fluid supply is charging the accumulator chamber 140 by passage 100 as described above, the non-return valve 144 being loaded by a very weak spring 148. When the solenoid 16 is energized, the pilot valve member 106 moves into a bore 110 to close communication between passages 90 and 94 and open passage 90 to passage 92 whereby fluid is fed to chambers 70 to move both valves 28 downwards to close ports 38 and open chambers 42 to chambers 34, thus reversing the connections to the motor. The pilot valve may be actuated manually by a push-rod through opening 132. A modified form of pilot valve is shown in Fig. 5 and comprises an armature 172 carrying valve closure portions 176, 178. The passage 100 from the fluid supply leads past a ball non-return valve 214 to an accumulator chamber 210. With the pilot valve in the position shown, chambers 70 are connected to exhaust by passages 86a, 166, grooves 192, passages 186, 168 to passage 96. When the solenoid is energized, valve member 176 seats and valve member 178 opens thereby connecting accumulator chamber 210 to chambers 70 by passages 188, 166 and 86a. A manually-actuated pilot valve member 200 may be provided which in the position shown, interconnects passages 86a and 168 as above through the solenoid valve and may be moved to the left to close this connection and open passage 86a to passage 213.