GB826762A - Improvements in fluid pressure braking systems - Google Patents

Abstract

826,762. Fluid-pressure brakes. COMPAGNIE DES FREINS ET SIGNAUX WESTINGHOUSE. Nov. 22, 1956 [Dec. 1, 1955], No. 35747/56. Class 103 (1). In a fluid-pressure braking system particularly for railway vehicles of the kind in which fluid under pressure supplied by an auxiliary reservoir is used to apply the brakes, the degree of braking being regulated as a function of the variation in the brake pipe pressure in relation to a reference pressure in a control reservoir, there is provided, throughout the length of the train and in addition to the usual brake pipe, a second pipe, charged to a substantially higher pressure than the normal brake pipe pressure of the system and placed in communication, at least during the release of the brakes, with the auxiliary reservoir, whereby the recharging of the auxiliary reservoir is expedited. In the embodiment shown in Fig. 1 a second pipe 7 is supplied throughout the length of the train in addition to the normal brake pipe 1; the pipe 7 being supplied at a pressure substantially above the brake pipe pressure. A pipe 8 connects pipe 7 through a retaining valve 9 to the upper chamber 11 of a charging valve 10 provided with a lower chamber 12 connected to the control reservoir 2; the charging valve 10 being responsive to differences between the fluid pressure in the auxiliary reservoir 5 and control reservoir 2. A connection 17 from the charging valve 10 to the auxiliary reservoir 5 is controlled by a valve 15 connected to diaphragm 13 such that the auxiliary reservoir is supplied through the high-pressure pipe 7 whenever valve 15 is opened. The opening and closing of valve 15 is controlled by diaphragm 13 subjected on one side to control reservoir pressure tending to open the valve and on the other side to auxiliary reservoir pressure assisted by spring 16 whereby the valve is closed when the auxiliary reservoir pressure attains a value such that its action upon the movable abutment together with that of the spring overcomes the opposing action thereon of the control reservoir pressure. In the event of an emergency brake application during release, the maintenance of the auxiliary reservoir 5 at a satisfactory pressure is ensured. As a safety during an emergency braking application excessive pressure is prevented by the provision of a pressure limiting arrangement 19 connected in pipe 18 between graduated release distributer 4 and brake cylinder 6. An alternative embodiment described in the Specification relates to an electro-pneumatic system.