| 摘要 |
PCT No. PCT/US80/00579 Sec. 371 Date May 16, 1980 Sec. 102(e) Date May 16, 1980 PCT Filed May 16, 1980 PCT Pub. No. WO81/03362 PCT Pub. Date Nov. 26, 1981.Fluid control circuits employed on construction vehicles to control the actuation of various work cylinders oftentimes include a system for sensing the fluid pressure in the cylinder and communicating such fluid pressure to a control device in signal form to closely control the displacement of a pump, the flow capacity of a pressure compensated flow control valve, or the like. The sensing system is normally associated with the spool of a directional control valve which must travel a substantial distance to effect extension or retraction of the cylinder and normally requires an "anti-rotation" device to insure proper alignment of the various ports and passages. Conventional high pressure systems of this type also pose potential leakage problems. This invention overcomes such problems by providing an improved load sensing system (45) including an annular land (32) defined on a spool (26) of a control valve (23) and an annulus (46) disposed axially between first (36) and second (37) outlets of the control valve (23) and further disposed to circumvent the land (32) of the spool (26).
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