Patent GB-437623-A (GB)
Title: Improvements in or relating to driver's brake valves for compressed air brakes
IPC: B60T15/04
Filed: 1934-07-13
Abstract: 437,623. Fluid pressure brakes. KNORR - BREMSE AKT. - GES., 9, Neue Bahnhofstrasse, Lichtenberg, HILDEBRAND, F., 2, Waldmannstrasse, Lankwitz, and MOLLER, E., 75, Kopenicker Allee, Karlshorst, all in Berlin. July 13, 1934, No. 20584. [Class 103 (i)] A driver's valve giving graduated braking, is arranged to give a high pressure charging period for the train pipe terminated when a compensating reservoir on the locomotive is charged and then a low pressure charging period in which the train pipe is charged to a pressure determined by a pressure regulator and the pressure in a timing reservoir. A valve 34 which can be opened in running and service braking positions by an auxiliary lever 33 on the driver's valve handle 19 admits main reservoir pressure fluid from passage 3 to passage 51 and by raising a valve 11 to passage 52 to the space beneath a piston 8 which is raised to open a high pressure valve 7 which admits main reservoir pressure past a valve 10 to the train pipe passage 4. A passage 27 supplied with fluid from the pressure regulating valve 25, 26 operated by driver's handle 19 is opened to the space above and below the piston 8 by passages 55, 57. The space above the piston 8 is connected to a compensating reservoir 9. The high pressure changing period terminates when this reservoir is charged, and the pressure above and below the piston 8 equalized. The piston 8 falls and valve 7 is closed and valve 10 closes, opening a valve 54 to release the pressure fluid from below the piston 8. The valve 11 recloses when fluid has leaked into its interior through an aperture 11<a>, thus rendering the valve 34 ineffective. The low pressure charging is effected by a double valve 12 connecting the train pipe 4 either to main reservoir pipe 3, 24 when a piston 13 is raised when charging the train pipe by the pressure fluid from the passage 27 supplied by the pressure regulator 25, 26 which is transmitted by cavity 44 in the rotary slide valve 40 and passage 36. A diagram of the valve 40 showing the cavities is superposed on the Figure. The pressure fluid from a timing reservoir 15, which is charged when the valve 7 is open by aperture 56 also maintains the valve 12 raised by means of a piston 14, and also raises a piston 17 which opens a large passage by means of a valve 16, between the train pipe and the valve 12. The train pipe pressure above the piston 13 gradually depresses the pistons 13, 14 as this pressure rises until a valve 58 in the piston 14 is opened by engagement with casing wall and releases the pressure from the reservoir 15, allowing the valve 16 to close, leaving only a restricted aperture 45 between the train pipe and the valve 12. When there is equal pressure on each side of the piston 13 the charging ceases. The pressure regulating valve 25, 26 comprises a double valve operated by screw thread 22 and by handle 19 and adapted to connect the passage 27 to main reservoir or atmosphere. The rotary valve 40 is also turned by the handle 19 and in running and service braking connects passages 27, 36 by cavities 44, 46 respectively and passage 39 to atmosphere 38 by cavities 47, 60 respectively. For service braking, the handle 19 is turned to connect passage 27 to atmospheric opening 28 reducing the pressure below the piston 13 which falls, opening the train pipe to atmosphere by valve 12 and passages 38, 39. The pressure regulator and the valve 12 return to lap position at each stage when the pressures on the controlling bodies 29, 13 balance. The valve 12 maintains the train pipe at the set pressure in case of leakage. For emergency braking the valve 40 is moved to connect passages 36, 43 to atmosphere at 38 by cavity 61, whereupon a piston valve 6 moves to connect the train pipe 4 to large atmospheric aperture 5. A valve 64 may be raised before the locomotive is coupled to the train by a member 18a to supply fluid to raise pistons 14, 13 and connect main reservoir and train pipe directly by the valve 12 to ensure equalizing between the train pipes of the locomotive and the train.