Patent GB-427161-A (GB)
Title: Improvements relating to electro-pneumatic brake equipment
IPC: B60T17/22
Filed: 1934-09-18
Abstract: 427,161. Fluid pressure brakes. WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London.-(Assignees of Farmer, C. C.; Pittsburg, and Hewitt, E. E. ; 221, Vine Street, Edgewood, both in Pennsylvania, U.S.A.) Sept. 18, 1934, No. 26746. Convention date, May 18. [Class 103 (i)] In fluid-pressure railway brakes, brake cylinder pressure is controlled by a relay valve 102 which is controlled either by an electric self-lapping valve 100, Fig. 2, or a triple valve 104 controlled by train pipe 82, both valves being controlled by a driver's valve 10, Fig. 1. A complete brake control system is provided on each end car so that the brake can be controlled from either end, the centre cars having the valve mechanism shown in Fig. 2 and a conductor's train pipe venting valve only with a train pipe local venting valve 18, Fig. 1, in addition. The current to valve 100 is controlled by cutting out increasing portions of a resistance 92 of contact 56 on a drum 52 of the driver's valve when the driver's valve is moved between positions II and III and the train pipe is controlled by a rotary valve 54 to give a pneumatic application in case of failure of the electric apparatus, by moving the driver's valve to position V. Emergency pneumatic application is obtained in position VI. In handle-off position VII timing and transfer relays 34, 79 are de-energized. Drum 52 and rotary valve 54 are rotated together by the driver's handle. A pneumatic emergency application occurs if an electrical service application is ineffective by venting of the train pipe 82 by valve 40 controlled by electric valve 38 controlled by a turning relay 34 which is deenergized by finger 71 and contact 56 when the driver's valve is moved to electric service position. If the electrical application is effective, brake cylinder pressure operates a pneumatic switch 36 to break the connection of the valve 38 to earth and prevents this valve operating. The fluid supplied to operate the relay valve 102 by either valve 100 or valve 104 is supplied to opposite sides of a check valve 220 so that in emergency when both valves are arranged to supply the relay valve only the supply which is predominant in pressure will reach the relay valve. Brake application is controlled by a pendulum switch 302 movement of which is dependent on the degree of retardation and is adapted to engage first a contact 308 and energize a cut off valve 230 to close the supply to the relay valve 102 and secondly if the retardation is greater still, a contact 310 to energize a release valve 246 and release fluid from the relay valve and thus effect the necessary degree of release of the brakes. Faults in the circuits of these devices is indicated by lamps 24, 26 controlled by relays 28, 30 and resistances 32, 33. If the train pipe leaks below a predetermined pressure pneumatic switch 42 closes a circuit for the valves 100 on each vehicle to produce a full service application. A lamp 22 indicator faults in the electrical circuits. A brake application may be effected from the track by a track switch 44 adapted to de-energize electric valve 46 which vents a valve 48 which vents the train pipe 82. This movement of the valve 46 opens a switch 398 so that the circuit through this valve cannot be completed until the driver's valve is moved to emergency position to connect fingers 68, 72 to the positive pole of the battery 78, so that the valve 46 is re-energized through wire 417 and the track switch 44, the corresponding valve at the rear of the train being energized through the finger 72 and a wire 454. The fluid supplied to operate the relay valve 102 passes directly through a quick inshot valve 202 which when a certain pressure is attained closes and this fluid now passes through the release and cut-off valves 230, 246. The train pipe venting valve 18, Fig. 1B, comprises a piston-operated slide valve 340 which when an emergency application is produced moves to connect a quick action chamber 344 to a chamber 336 to operate piston and valve 360, 326 to vent the train pipe 82 to atmosphere at 332. When a service application is produced this piston valve 340 is arrested by a spring stop 352 so as merely to vent a chamber 344 to atmosphere at 332, no train pipe venting taking place. The relay valve 102 comprises a piston 134 controlling exhaust passage 152 and supply passage 128 for the brake cylinder 16 and recloses automatically at each stage of braking. The supply valve 110 comprises a pilot valve 118 and supplies fluid from a reservoir 14 which is charged directly from the main reservoir. The electric self-lapping valve 100 also utilizes fluid from the reservoir 14 and comprises a diaphragm 182 on which the supplied fluid acts to close the supply and exhaust valve 180 to lap position. The valve 100 is provided with screw adjustments 196. The triple valve 104 supplies fluid from auxiliary reservoir 294 and comprises rapid recharge valve 290 connecting the train pipe to the triple value chamber by slide valve passage 284. This valve closes at a certain pressure. The relays 28, 30 at the operating end of the train' are connected to train conductors by contacts of the transfer relay 79, at the non-operating end they are connected to earth by back contacts of the transfer relay. Lamps 24, 26 are not lighted in running conditions due to rectifiers 442. Lamp 26 lights when pendulum switch 302 engages the contact 308 and lamp 24 lights when the pendulum switch engages the contact 310. Faulty energization of electric valves 230, 246 is prevented by rectifiers 4421.