GB120652A - Improvements relating to Fluid Pressure Braking Apparatus. - Google Patents

Abstract

120,652. Cloud, J. W Nov. 30, 1917. Fluid-pressure. - Relates to means for graduating the release of compressed-air brakes in which the triple valve exhaust is controlled by an additional valve subject to train-pipe pressure and brake cylinder pressure acting in opposition to the pressure in a normally closed cliamber and consists in reducing the pressure in this chamber to a predetermmed valvo prior to the release operation, so that release may not he delayed or prevented. According to one arrangement, the triple valve exhaust port is connected by a passage 17 to a casing 18<1> provided with exhaust ports 19 controlled by an abutment 18 which engages a lever 14 connected also to a slide valve 4, the piston 2 of which is subject on one side to the pressure in the train-pipe connected at G, and on the other side to the pressure in a chamber 7. In the fully released position, the slide valve connects the valve chamber 12 with the chamber 7 through a passage 25 so that air from the trainpipe can feed into this chamber. When the trainpipe pressure is reduced to apply the brakes, the slide valve 4 connects the chamber 7 to a passage, (not shown), leading to a blow-down valve or, according to the Provisional Specification, it may be to another receptacle, so that the pressure in this chamber is reduced to a pre-determined value. A spring 11 may be provided on the trampipe side of the slide valve. In a modification, the triple valve exhaust is connected to the chamber in which the spring 11 is disposed, the lever 14 being dispensed with. The slide valve 4 also is dispensed with, the feed from the train-pipe to the chamber 7 being by way of a port in the wall of the piston chamber 3, and the stem 40 of the piston being formed as a valve for controlling the communication between the chamber 7 and the blow-down valve. A port 29 may be formed in the abutment 18 to ensure the complete release of the brakes.