Patent GB-263930-A (GB)
Title: Railway brake construction and control means therefor
IPC: B61K7/04
Filed: 1925-10-05
Abstract: 263,930. Marks, E. C. R., (Hannauer Car Retarder Co.). Oct. 5, 1925. Frictional apparatus on permanent way: fluidpressure; electric.-Track brake mechanism is provided with electrical control mechanism including a lever adapted to be moved into different positions to cause the braking pressure to be increased in a step-by-step manner. Members connected to the brakes by yieldable means may be given a stepped movement to press the brakes against the vehicle wheels with a variable pressure, or fluid of different pressures controlled by electrically-operated valves may operate the brakes. The brake comprises sections 10, 11, Fig. 1, on each side of each rail 14, 15, connected through springs and guide rods to backing bars 28, 29. These bars are connected respectively to transversely extending members 16, 17 connected to bell cranks 26, 27. The bell cranks may be substituted bv levers and links. The bell cranks are connected to an actuating bar 18 adapted to be moved by levers 19 fulcrumed at 9 and connected intermediately to the bar 18. In one method of operation, the levers 19 are operated by electric motors 20 through screw gearing 22 and a spring connection 25 loosely connected to the lever 19. The motor circuit is made by a switch operated by a solenoid, the switch comprising two arms, one in each connection of the motor to the mains. The lever of a master controller is adapted to complete in turn a number of circuits through the solenoid by movement over contact segments, each circuit being broken, after the brakes have moved a certain distance, by the rotation of two drums 55, Figs. 3 and 7, through arms 43 and a connection 40 to the lever 19, Fig. 1. The drums 55 comprise interconnected segments 53, 54, and 62, 63 adapted to coact with stationary brushes 50, 60 arranged in the solenoid circuits. To allow for slack in the brake mechanism, the connection 40 comprises rods 39, 41 and a bolt 47 secured in the rod 41, movable in a slot in the rod 39, and adapted to engage an adjustable band 49 secured to the rod 39. Reverse movement of the master controller completes circuits through a further solenoid operating a switch comprising two arms adapted to reverse the current through the motor and so release the brakes step-by-step, the circuits being broken in turn by the reverse movement of the drums. An immediate full release of the brakes may be effected by movement of the control lever to the end contact segment. A coil winding is included in the motor circuit for applying brakes adapted to stop the motor when the motor-circuit is broken. In the modification in which electrically-controlled fluid-pressure devices operate the brakes, the levers 19, Fig. 11, are connected to the piston rods of brake cylinders 123 provided with pipes 163, 165 leading to each end of the cylinders and controlled by inlet and exhaust valves A, B, C, D, E operated by solenoids 124, 125, 126 by means of crossmembers 129 and counterweighted levers. On moving a controller to close the circuit for the solenoid 124, valves A, B are opened and pressure fluid passes through valve B to the lefthand ends of the brake cylinders to apply the brakes. The pressure fluid is supplied through a main 148 and a reducing valve 150 which can be regulated to give any desired pressure. Fluid is exhausted from the right-hand end of the brake cylinders through the valve A. When the circuit for the solenoid 125 is also closed the valve C is opened to admit full fluid pressure for applying the brakes. The brakes are released under full pressure when the controller arm is moved to break the circuit of the solenoids 124, 125 and close the circuit for the solenoid 126. The valves A, B. C are thus closed and the valves D, E opened. Pressure fluid passes by valve D to the right-hand end of the cylinders and is exhausted from the left-hand end to give the levers 19 a reverse movement. The master controller is located in a tower for remote control.