| 摘要 |
1483070 Brake valves S SHIBER and R H HUSTED 31 July 1974 [14 May 1974] 12120/77 Divided out of 1483069 Heading F2F A brake valve 10 providing a pressure output in response to a driver's force input or using the latter when hydraulic power is insufficient comprises a variable volume chamber 49 having a fluid inlet including a check valve 48 and a pressure output port, actuating means including a shaft 19 for accepting an operators force input, the housing including a wall movable for reducing the volume of the variable volume chamber and a variable orifice 59 bypassing the movable wall, a flow passage through the brake valve from the inlet, through the chamber 49 to the orifice 59 and means including a reaction piston 31 connected with the actuating means and movable relative to and engageable with the movable wall for selectively restricting and closing the orifice 59 and then shifting the movable wall so that during power operation the force input causes restriction of the orifice and flow through the passage to increase pressure at the output port and during manual operation the orifice 59 is closed and the wall is moved to reduce the volume of the chamber 49 and manually pump fluid through the output port. The orifice 59 is a circumferential variable orifice formed between annular piston 15 and piston 31 and narrows in response to the force input and during "power-off" operation the input force causes'piston 15 to abut piston 31 and pull it towards the end wall while maintaining the orifice 59 closed. |
