| 摘要 |
A lock valve (10) for use in a hydraulic system (90) for positioning the work implement of an earth working machine which includes first and second check valves (28, 30) and a piston section (60, 70, 62, 72) for each operable by pilot fluid. In a first mode, the piston sections (60, 70, 62, 72) permit seating of both check valves, while in a second mode, the piston sections interlock so that only one check valve can seat. The lock valve (10) operates in a hydraulic system (90) to lock a work implement, such as a blade for a motor grader, in a fixed position during a first operating mode, while providing a connection from one end of an implement actuator to vent during a second operating mode to insure that a shock absorbing means for the implement hydraulic system maintains a full shock absorbing capacity. |
