| 摘要 |
<p>1,016,820. Valves. ROSS OPERATING VALVE CO. Jan. 9, 1964 [Feb. 20, 1963], No. 1087/64. Heading F2V. Two simultaneously operated three-way main valves 12, 13 (Fig. 1, not shown), over which the supply and exhaust of fluid pressure to and from a jack 14 is effected, are controlled by a pilot valve 47 operated by opposed solenoids 48, 49. The lower seat 34 of valve 13 is a spring- loaded differential piston and whilst the inlet pressure in a chamber 17 remains above a given level it holds this seat in the position shown. Should the supply pressure fall then the springs 28, 43 will move the closures of valves 12, 13 upwardly; in the latter case the spring 43 will lift its closure via the seat 34 which thus remain in contact with its closure so that chamber 17 is not connected to the right-hand end of the jack 14, which thus remains in the position shown. When the fluid pressure is restored the closure of valve 13 will remain in engagement with the seat 34 until the parts arrive in the position shown.</p> |
