Patent GB-342566-A (GB)
IPC: B60T8/18
Filed: 1930-03-05
Abstract: 342,566. Fluid - pressure brakes. WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London.-(Assignees of Farmer, C. C. ; 7008, Thomas Boulevard, Pittsburg, U.S.A.) March 5, 1930, No. 7228. Convention date, March 12, 1929. [Class 103 (i).] Brake apparatus comprising a " load " brake cylinder to which pressure fluid is supplied, in the case of a loaded vehicle by a valve device after a predetermined pressure is established in a " light " cylinder which alone is operative for an empty vehicle is provided with an additional valve adapted to prevent any reduction in the pressure obtaining in the " light " cylinder due to flow of fluid to the " load " cylinder. The " load " cylinder 5 comprises a push rod 34 slidable in the piston rod 33 and adapted to be coupled to the piston rod by a spring-latch 36 when a pin 39 is disengaged from the cylinder upon movement of the piston 32 thus permitting idle movement of the rod 34 when the piston of the " light " cylinder 4 only is moved. With the parts of the valve mechanism in the normal position shown, air is supplied from the train-pipe 1 through the groove 17 to chamber 13 and auxiliary reservoir 3. When the pressure in the train-pipe is reduced to apply the brakes, air from the reservoir 3 is supplied at first to the cylinder 4 through valve port 60 passage 61 past the valve 26 and passage 43. When the cylinder pressure reaches a value sufficient to overcome the spring 23 the valve piston 18 moves its lower position permitting the valve 26 to seat so that air is supplied to the cylinder only through a restricted passage 45. The movement of the piston 18 from its seating also opens a supply of air by way of the passage 45 through passages 46, 49 to a diaphragm chamber 28 and when the pressure in this chamber and thus also in the cylinder 4 is sufficient to overcome the spring 31 the diaphragm is depressed to open a valve 29 permitting the supply to the " load " cylinder 5. The valve 29 will at first be opened only to an extent sufficient to permit supply from the chamber 28 to the cylinder 5 at a rate equal to that at which the chamber is supplied, so that fall of pressure in the cylinder 4 is prevented. The valve will open fully when the pressures in the two cylinders are equal. Should for any reason the air in the cylinder 4 vent into the cylinder 5 the piston 18 will return to open a port 53 and vent the cylinder 5 to atmosphere. When train-pipe pressure is raised to release the brakes the air in both cylinders at first escapes through passage 43, triple valve cavity 54, restricted passage 56, and port 57. When the piston valve 18 returns to its upper position the exhaust of the cylinder 5 is completed through the port 53. When a quick release is required a cock 9 is turned to the position shown to provide an additional passage 58. The cylinder 5 may be cut-out by turning the cock 8 to a position in which communication between passages 43 and 61 and that between 46 and 49 are cut off and passage 49 is connected to passage 55 to connect the chamber 28 to the exhaust port 57. When the cock 8 is in thr cut-off position the passages 43, 61 may be com pletely cut off so that the supply to the cylinder 4 ceases when the piston valve 18 is depressed or a restricted passage may be provided in the cock through which the supply continues.