GB399159A - Improvements in and relating to self-lapping driver's brake valve devices - Google Patents

Abstract

399,159. Fluid-pressure brakes. WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London.-(Assignees of Lynn, E. K. ; 1372, Broadway, East McKeesport, and Bush, R. J.; 340, North 1st Street, Jeannette, both in Pennsylvania, U.S.A.) April 29, 1932, No. 12403. Convention date, Oct. 16, 1931. [Class 103 (i).] A driver's brake valve has admission and release valves adapted to be actuated manually without operating the piston and spring device used for automatically returning the valve device to its lap position. The admission valve 18 which is urged towards its seat by a spring 20 is slidably mounted in a liner 17 and is provided with a socket to receive one end of an operating rod 48 pivoted at 47 to a floating double lever 41 pivoted at 42 to a slidable plunger 43. The other ends of the levers 41 carry a roller 46 adapted to engage the stem 35 of the release valve 32. This valve is housed in a piston 25 and is urged from its seat by a spring 38 lighter than the spring 20, outward movement being limited by a collar 36 engaging a stop plate 40. The piston 25 which is subject to the pressure being controlled is acted on by an adjustable spring 29 stronger than either of the springs 20, 38 and has a rod slidably mounted in the spring abutment 22. The plunger 43 is moved by a cam 53 on a rotatable shaft adapted to be operated by a removable handle 55. In the position shown the control chamber 11 is connected to atmosphere through valve 32 and exhaust passages 34, 28. On rotating the cam to depress the plunger, the exhaust valve first closes and then the admission valve opens. As the pressure builds up in the chamber 11 the piston is moved back against the action of' the spring 29 allowing the spring 20 to close the admission valve when the desired pressure has been reached. When the cam is turned to depress fully the plunger 43, the admission valve is not closed even when the piston has been moved until the piston-rod contacts with an adjustable stop 24 so that the maximum pressure of the supply is built up in the chamber 11.