GB902858A - Improvements in and relating to release valves for automatic compressed air brakes - Google Patents

Abstract

902,858. Fluid-pressure brakes. VERWALTUNGSGESELLSCHAFT DER WERKZEUGMASCHINENFABRIK OERLIKON. July 24, 1958 [July 26, 1957], No. 23851/58. Class 103(1). A release valve device for an automatic compressed air brake comprises a three chamber release valve having a constant pressure chamber 16, a constant pressure reservoir connected with the latter chamber by a connecting pipe 27, a valve device having a vent valve 32 for venting the chamber 16, and a first auxiliary valve 24, 25 having a part 24 coupled with the vent valve 32, the first auxiliary valve holding the connecting pipe 27 open when the vent valve 32 is closed, but closing the connecting pipe 27 when the vent valve is open. In the position shown in Fig. 1a release valve device 19 is seated against its valve seat 33 so that compressed air from a constant pressure reservoir 28 is supplied via open orifice 26, chamber 17 and space 31 to the control pressure space 31 below diaphragm 4 of a triple valve TV. When the pressure in the brake pipe 1 is lowered to apply the brake, the pressure drop firstly releases the brake pipe pressure in chamber 3 of the triple valve and allows valve 8 to be opened by valve stem 13, due to the action of the control pressure in chamber 31, and allows auxiliary reservoir (5) pressure to pass into brake cylinder 9 to apply the brakes. Simultaneously, the pressure drop causes membrane 43 and stem or latch member 41 to be moved to the right under the action of spring 52. When it is desired to release the brake on an individual bracked vehicle, an operating lever 39 is pulled to the intermediate position shown in Fig. 2, the stem 41 moving further to the right to prevent lowering of stem 19 and raised the vent valve 32 off the seat 33 so that the upper cylindrical portion 24 of the stem 19 enters the central orifice 26 of a second auxiliary valve 21 without lifting the latter from its seat 23. By this operation, communication between the constant pressure reservoir 28 and the chambers 17 and 31 is interrupted and the compressed air in chamber 31 can escape to atmosphere through open valve seat 33, chamber 18 and orifice 34 in the release valve device. The valve assembly of the triple valve then moves downwardly to open the brake cylinder 9 to atmosphere via hollow valve stem 13 and orifices 14 and 15 to release the brake. When it is desired to reduce the pressure in the constant pressure reservoir 28, the operating lever 39 is pulled to an extreme inclined position so that the stem 19 is raised further and the second auxiliary valve 21 is lifted completely off its seat. Specification 902,859 is referred to.