| 摘要 |
Directional control valve includes a manually operated pilot valve stage and a hydraulically operated power valve stage to isolate the pilot valve stage from the effects of the high axial flows passing through the power valve stage. The pilot valve is spring loaded in the stow direction as long as the directional control valve is disconnected from system pressure. Such spring also acts as a stowed condition linkage pre-tensioner to avoid fretting of various parts during vibration conditions and the like. When system pressure is applied to the directional control valve, such preload is automatically removed from the pilot valve for ease of movement between the stow and deploy positions by a relatively low manual input rotary force.
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