| 摘要 |
<p>PURPOSE:To enable a circuit for detecting the non-operation states of all change- over valves, to be composed by regulating the rotation of an engine at a high or low speed with the detection signal of pilot pressure passing sub-valves with applied pilot oil circuits, and one of side values, at least. CONSTITUTION:Pilot oil circuits which are provided with the passages of pilot pressure to be worked on the pilot pressure accepting section 25 of a rectilinear propagation valve 24, to be interrupted when running valves 17'L, 17'R are placed at neutral positions on sub-valves 34L, 34R to be interlocked with the running valves 17'L, 17'R, and to be opened at the time of operating them, are arranged. In the meantime, a doser valve 22' and a swing valve 23' for change-over valves except the running valves are provided with side valves 35, 36 so that the passages may be interrupted when the closer valve 22' and the swing valve 23' are set at neutral positions and the passages may be arranged at passage opening oil circuit positions at the time of switching the positions. Then, pilot pressure passing one of both the valve groups at least is worked on a change-over valve operation detecting pressure switch 40.</p> |
