GB794782A - Improved fluid pressure braking apparatus - Google Patents

Abstract

794,782. Fluid-pressure brakes. WESTINGHOUSE AIR BRAKE CO. May 15, 1966 [May 18, 1955], No. 15048/56. Class 103 (1). Fluid-pressure brake contro apparatus comprising the usua brake pipe 1, and main reservoir 2, includes also a reductioi limiting reservoir 3, an equaliz ing reservoir 4, a first or tern porary suppressive reservoir 5 a second reduction reservoir 6 a timing valve device 7 associ ated with a timing reservoir 8 a suppression valve device 9 associated with reservoir 10, a stop reservoir 11 and a timing reservoir 12. Included in the various sections of the casing indicated generally at 23 are a service application valve 32, a brake pipe cut-off or double heading valve device 33, a first service cut-off valve 34, an equalizing valve device 35, a brake pipe maintaining cut-off valve 36 and a cut-off valve 37. The brake valve handle 39 may be moved to any one of five control positions and the operation of the control apparatus is characterized primarily in that " flat maintaining operation " or means whereby the brake pipe pressure is maintained against leakage at the value of pressure prevailing in the equalizing reservoir 4 takes place at all times when the control handle 39 is in the " First Service " position, and also when the handle is in the " Lap " and " Service " positions, provided also that the handle 138 of the maintaining valve 36 is in cut in position whereby the check valve 129 is unseated to supply fluid at feed valve pressure from passage 132 to passage 88. The " flat maintaining action " is brought about by the fact that the pressure in the brake pipe 1 is, under certain conditions, existent in space 99 below the diaphram 95 of the equalizing valve device 35 and the pressure in an equalizing reservoir 4 is connected to space 97 above the diaphragm 95. Thus, if the brake pipe pressure in space 99 falls below a certain value, diaphragm 95 is depressed to unseat valve 111 and allow feed valve pressure in pipe 88 to restore the brake pipe pressure to its required value. The timing valve device 7 is controlled through train stop signal circuits (not shown) acting on an electromagnet 13 and includes a pneumatically operated whistle 19. The suppression valve device 9 may be as described in U.S.A. Specification 2,322,042 and the apparatus includes a first service cut-off valve device 34 which in closed position disconnects passages 91, 92 so that in such position fluid under pressure cannot be supplied from the first suppression reservoir 5 to the pipe 93 and suppression valve device 9 even though the brake valve handle 39 is moved to first service position. Thus an improper suppression of an automatic train control brake application is positively prevented.