GB1434553A - Manually operable brake valves - Google Patents

Abstract

1434553 Drivers' valves ROBERT BOSCH GmbH 20 July 1973 [24 July 1972] 34727/73 Heading F2F An inlet valve is influenced by a manually operable lever and is responsive to and adapted to be closed by fluid pressure downstream thereof attaining a predetermined value thus retaining this downstream value irrespective of fluctuations in upstream pressure, the lever upon movement into a given brake application position opens an exhaust valve, the inlet valve operating as above when the lever is not in this position. With the lever 16 in the position shown (not the application position), pneumatic fluid enters an inlet 30, passes along the outside of a hollow stem 5 and through the inlet valve comprising a shoulder 23 on the stem and a seal 24 until pressure acting on the stem overcomes the force of a spring 6 of the valve to close the inlet valve thus limiting the downstream pressure at an outlet 33, when the lever 16 is moved rightwardly to a second position, a plunger 11 is forced down by an eccentric cam 15 to move a plate 9 to remove the spring force from the stem 5. Furthermore the exhaust valve, constituted by a plate 13 and a shoulder 20, is opened to exhaust pressure at the outlet 33 to atmosphere via passages 22, 21, 38. The pressure responsive areas of a piston end 27 of the stem 5 and of the annulus of the seal 24 are equal so that the freely floating stem 5 is not moved by inlet pressure fluctuations. With the downstream pressure at atmospheric pressure, a spring 19 retains the inlet valve closed.