Patent GB-748989-A (GB)
Title: Improvements in hydraulic control valves
IPC: F15B11/042
Filed: 1951-10-04
Abstract: 748,989. Fluid-actuated valves. GRATZMULLER, J. L. Oct. 4, 1951 [Oct. 9, 1950], No. 7782/54. Divided out of 748,932. Class 135. A hydraulic control valve assembly for controlling the delivery of liquid from a source of liquid under pressure such as an accumulator A to an outlet Q comprises a main valve 1 giving a relatively rapid fluid flow from the source to the outlet, an auxiliary valve 4 having a restricted passage 6 and giving a relatively slow fluid flow from the source to the outlet, a passage between the delivery side of the valves and an exhaust opening 53, a movable member, such as the hollow stem 3, movable in one direction to close the said passage, open the auxiliary valve, and finally the main valve, and movable in the other direction to perform these operations in the reverse order, and controllable relay means 10 for actuating the movable member. As shown in Fig. 1, the valves 1, 4 are arranged in a block C which supports the accumulator A on its underside and a reservoir B on its upper side, a rib 21 on the latter being held against a packing 22 by screwed studs M. The seating 64 of the main valve 1 is held in the block C by a screwed casing 45 the lower end of which is slightly expanded by a tapered part on the seating 64. The main valve is held against its seating by a spring 61 guided by a stud 62 mounted on a transverse rod 63. The upper end of the spring 61 abuts against a plate having a restricted orifice 6 leading to the auxiliary valve which is formed as a ball 4 having a seat 4a. The ball 4 is adapted to be moved from its seat by a plunger comprising a rod 5 with a head 43 slidable with clearance in a bore 40 and a separate or intermediate member 2 adapted to co-operate with the lower end of the hollow stem 3. On subsequent movement of the plunger, the head 43 engages a shoulder 44 and opens the main valve. On opening the valve 4 a restricted flow of liquid takes place through the orifice 6, the seat 4a, a lateral hole 7, and a passage or groove 42 to the outlet Q which may lead to a hydraulic motor or like device. When the lower end of the stem 3 engages the intermediate member 2 it cuts off the delivery side of both valves from the tank B via openings 52, 53. The actuating means for the hollow stem 3 comprises a piston 10 slidablo in the upper part of the casing 45 against a spring 8. Pressure liquid from the accumulator A is admitted to the space above the piston 10 under the control of a relay valve 12, Fig. 4, connected to the accumulator A by a pipe L. The valve 12 is mounted in the top of the casing in a chamber 54 and held in place in the chamber 54 by a screwed cap 55 in which is mounted a spring-pressed push-button K. The valve 12 has a central three diameter passage 20, 20a, 20b, a ball inlet valve 18, the downward movement of which under gravity is limited by an abutment 50, and an outlet or exhaust valve in the form of a slidable rod 16 which is a close fit in the passage 20 and is adapted to be lifted by the fluid pressure acting on the piston 10 to expose exhaust passages 46 when the push-button is released. A further ball 19 and a rod 17 of the same diameter as the rod 16 are interposed between the rod 16 and the ball 18. Two sets of radial passages 47, 49 connect a passage or passages 48 leading to the space above the piston 10 with the passage 20, 20a, 20b, the passages 47 opening into the intermediate section 20a, and the passages 49 at the junction of the sections 20, 20a. As shown in Figs. 4 and 7, the ball 19 is incapable of blocking the passage 20 in the release position.