| 摘要 |
A pneumatic control assembly includes a valve forming a bore that is openably blocked by a spring-biased, first plug. An inner rod is movable in the bore with a lower end engageable with the first blockage plug and an upper end forming a second plug. The inner rod is spring biased to separate from the first plug. An intermediate rod forms a channel having an opening confronting and separated from the second plug by a basing spring. A vent hole is defined in the intermediate rod and in fluid communication with the channel. A piston is formed around the intermediate rod between the opening and vent hole. An outer rod is supported on the piston by a resilient member. When the outer rod is forced toward the intermediate rod, the resilient member is deformed, driving the intermediate rod toward the inner rod and the second plug blocks the opening of the intermediate rod. The engagement between the intermediate and inner rods drives the inner rod to urge the first plug to open the bore. Working fluid is thus allowed to flow through the bore of the valve. When the outer rod is released, the first plug is returned and blocks the bore again. The opening of the intermediate rod is separated from the second plug to allow the working fluid residual in the bore to vent through the vent hole.
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