GB214703A - Improvements in triple-acting valves for the compressed air-brakes of trains, tram-cars, and other vehicles - Google Patents

Abstract

214,703. Sch³ren, H. Jan. 22, 1923. Fluid-pressure.-A triple valve comprises a pair of connected pistons subject to the opposing pressures in the train-pipe and the auxiliary reservoir and' held by springs in the lap position when these pressures are equal so that a partial release of the brakes can be obtained. An additional passage is uncovered by excess of pressure in the train-pipe for effecting a rapid recharging of the auxiliary reservoir. A sudden drop in train-pipe pressure opens an additional supply passage to the brake cylinder. The cross-section of the brake cylinder supply passage can also be adjusted bv hand according to the nature of the train. The casing 1 of the valve is connected to the train-pipe at 24, to the atmosphere at 26, to the brake cylinder at 27, 30 and to the auxiliary reservoir at 25. A needle valve 15 sliding in the end wall of the casing and controlling a passage 7, 8 in the rod 4 connecting the pistons 5, 6 is urged to the closed position by a spring 19. Under running conditions, with the train-pipe and auxiliary reservoir pressures equalized the parts assume the position shown under the influence of the springs 14, 19. In charging, with a slight excess of pressure in the train-pipe the pistons move to the right and unseat the valve 15, permitting air to flow from the train-pipe to the auxiliary reservoir through the passages 7, 8. With a considerable excess of pressure in the train-pipe a further feed passage 34, 32 to the auxiliary reservoir is uncovered. In effecting an application of the brakes, one or both of the passages 27 according to the suddenness of the train-pipe pressure reduction, is uncovered to the reservoir chamber R until equalization of the reservoir pressure with that in the train-pipe causes the return of the pistons to the position shown. A partial release of the brakes can be obtained by slightly raising the train-pipe pressure when the piston 6 uncovers one of the passages 27 to the atmosphere chamber A until upon equalization of the train-pipe and reservoir pressures through the passages 7, 8, the pistons are returned by the spring 14. A cock 29 has a number of passages of varying cross-section one or the other of which is interposed in the. brake cylinder passage 27, 30 according as the valve is for use on a goods, passenger or an express train.