| 摘要 |
1,130,943. Hydraulic brakes. AUTOBRZDY JABLONEC NARODNI PODNIK. 16 March, 1966 [20 March, 1965], No. 11446/66. Heading F2F. A master cylinder of the kind having a large diameter piston 2 and a small diameter piston 6 working in a stepped bore, and comprising an arrangement of valves and passages such that the delivery of a large volume of fluid at low pressure at the outlet 11 is followed by the delivery of a smaller volume at higher pressure, has a passage 31 in the small diameter piston 6, so that initially the latter is ineffective, and a valve 24 carried by a stem 25 for closing this passage, the stem being slidable in a twopart sleeve 12, 13 which also contains a ball valve 15 loaded by a spring 17, the arrangement being such that when a predetermined output pressure is exceeded the ball valve opens and allows fluid to escape to the reservoir (not shown), by way of a restricting orifice 19; piston 2 then moves until valve 24 contacts piston 6 and closes the passage 31, whereupon extension pin 28 of stem 25 engages the ball valve to maintain it open, the output being subsequently at the higher pressure determined by the smaller diameter of piston 6, which is pushed along by the stem 25. The piston 2 carries a slidable seal 3 on its flange 33 which, during the return stroke of piston 2, uncovers radial passages 35 communicating via axial passages 34 with the low pressure chamber in front of piston 2, so that fluid can return to this chamber freely from the reservoir. |
