Patent GB-935551-A (GB)
Title: Improvements in or relating to air pressure actuated braking systems
IPC: B60T15/12
Filed: 1959-11-18
Abstract: 935,551. Fluid pressure brakes. REGIE NATIONALE DES USINES RENAULT. Nov. 18, 1959 [Dec. 8, 1958], No. 39179/59. Class 103 (1). An air-pressure actuated railway braking system has automatic and direct systems actuating a brake cylinder according to the setting of a controller 10, a controller 19 varying the degree of braking pressure. The " direct " and " automatic " controller 10 has a shaft 11 and cams 12, 13, 14 controlling valves 15, 16, 17 and brake pressure controllers 19 have a shaft 18 and cams 20, 22, 30, 33 controlling valves 21, 23, 31, 33. The pressure reducing valves 21, 23 comprise a chamber 28 connected via valve 15 or 16 to a main air line 8 (at 115 p.s.i.), a diaphragm controlled vent 29 and a double valve 26 controlling the supply of air to, or the venting from, pipe 3 or chamber 40 in relay valve 36. In " direct " braking only the towing vehicle brakes are applied whereas the brakes of the whole train are applied in " automatic " braking. With controller 10 set for "direct" braking, cam 12 opens valve 15 to connect line 8 to chamber 28 of valve 21, cam 13 closes the line between valve 23 and line 8; and cam 14 operates valve 17 to supply air from line 8 to valve 44 to move piston 47 and close line 5 between triple valve 6 and brake cylinder 1. In position I of hand wheel 19, Fig. 3, for maximum braking; the member 27 of valve 21 is lowered to open valve 26<SP>1</SP> to deliver air at 70 p.s.i. via valve 2 to the brake cylinder 1. The member 27 of valve 21 is raised to open valve 26<SP>2</SP> to vent valve 23, balancing reservoir 43 and chamber 40 of relay 36, the train pipe 7 being vented via relay 36 and the opened rapid exhaust valve 31. Valve 33 is closed by cam 32. In position II-III, member 27 of valve 21 is raised to vent brake cylinder 1 via valve 26<SP>2</SP> until closed by diaphragm 24, the brake cylinder pressure being adjusted between 0-70 p.s.i., and the brake being completely released in position III. In position IV-V, cam 20 no longer actuates valve 21; and in position IV valve 33 is opened to supply train pipe 7 direct from line 8, a warning whistle is operated but pressure in pipe 7 does not rise due to venting via relay 36. The hand wheels 19 may control acceleration between position IV and V which is the normal running position. With controller 10 set for automatic braking; cam 12 closes valve 15 and line from line 8 to valve 21; cam 13 operates valve 16 to connect line 8 to valve 23; and cam 14 operates valve 17 to vent the upper chamber of valve 44. In position I, valve 23, reservoir 43, relay 36 and pipe 7 are vented as before to operate triple valve 6 to pressurize brake cylinder 1 from auxiliary reservoir 4 via valves 2 and 44. Chamber 28 of valve 21 is vented via valve 15. In position II, cam 30 closes valve 31 and, valve 26<SP>1</SP> of valve 23 is opened to supply air to relay 36 until pressure reaches |38.5 p.s.i. relay 36 charges pipe 7 similarly causes triple valve 6 to partially release the brakes. Reservoir 43 is charged to prevent pressure surges in chamber 40. Between position II and III, train pipe pressure is gradually increased to 70 p.s.i. in position III for complete brake release. In position IV, cam 32 opens valve 33 to supply air at 115 p.s.i. from line 8 to pipe 7 for fast brake release, the whistle 35 is sounded and the pressure in pipe 7 gradually reduced to 70 p.s.i. via relay 36. Between position IV-V brakes are maintained released for normal running as before. The shafts 11 and 18 may be interlocked to prevent rotation of shaft 18 until controller 10 is in the " direct " or " automatic " position, shaft 11 only being rotatable when shaft 18 is in position I, i.e. the maximum braking position.