| 摘要 |
PCT No. PCT/US80/00766 Sec. 371 Date Jun. 16, 1980 Sec. 102(e) Date Jun. 16, 1980 PCT Filed Jun. 16, 1980 PCT Pub. No. WO81/03689 PCT Pub. Date Dec. 24, 1981.A fluid power control system (17) having an improved control valve (20) providing reduced regulated pressure fluid selectively from a high pressure pump supply (P) or the fluid motor (10) under conditions wherein the pump supply has failed to supply the desired pressurized fluid. The system utilizes a control valve (20) having a spool (29) provided with first transfer passage (41) and second transfer passage (42). The first transfer passage is adjustably throttled as a result of movement of the spool relative to an adjacent inlet port (37) and the second transfer passage (42) is adjustably throttled by movement of the spool relative to an adjacent inlet port (38). Inlet port (37) is connected to the high pressure fluid supply P and inlet port (38) is connected to the head end (13) of the cylinder (11) of the fluid motor through a check valve (44). Valve (20) provides selective pressure regulated fluid through an outlet port (36) thereof either from the pressurized fluid supply P when that apparatus is functioning or from the fluid motor in the event of a failure of the fluid supply. In each case, the valve provides the fluid at a desired operating pressure. The pressure regulated fluid may be used to operate a pilot valve (22) controlling a main valve (14) for adjustably positioning the piston (12) of the fluid motor.
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