| 摘要 |
<p>1300306 Valves OLMSTED PRODUCTS CO 7 Sept 1970 [4 Dec 1969] 42785/70 Heading F2V A spool valve comprises two spool members telescopically arranged in a casing, each member having an opening therein communicating with an internal bore of the member. As shown in Fig. 1 the valve is connected to a pump, reservoir and working cylinder 12. Control chambers 58 and 60 are pressurized to force the members together in which position the chamber 30 connected to the pump is cut-off from the working cylinder 12, the latter being connected to the reservoir on the one hand by chambers 38, 26 and line 36 and on the other hand by chamber 50 bores 96, bore 72, chamber 38 and line 36. Venting the control chambers 58 and 60 allows pump pressure acting on faces 88, 90 of the spool members to force the latter apart in which position (Fig. 4, not shown) the pump is connected to both sides of the working cylinder. The piston 97 moves rightward under the differential force on it. Control pressure applied to chamber 60 also causes movement of the piston 97 to the right but without fluid loading since the chamber 50 is connected to the reservoir (Fig. 2). Venting chamber 60 and pressurizing chamber 58 causes movement of the piston 97 leftwards (Fig. 3, not shown).</p> |
