Patent GB-407349-A (GB)
Title: Improved compressed air brake system and apparatus for tramway and railway vehicles
IPC: B60T15/04
Filed: 1932-09-07
Abstract: 407,349. Fluid - pressure brakes. PETERS & CO., Ltd., G. D., and PORTER, A. S., Slough, Buckinghamshire. Sept. 7, 1932, No. 24972. [Class 103 (i).] A driver's valve comprises a spring loaded abutment 18, Fig. 1, separating an exhaust duct 25 from a duct 11 leading to the main reservoir and a duct 14 leading to the brake cylinder, a screw 58 and a bolt 41 for adjusting the initial compression of the springs 45, 46, axially aligned tappet valves 3, 4 controlling the compressed air supply and the exhaust respectively and loosely coupled together by a pin and slot connection 32 and having springs 5 closing the valve 3 and a spring 7 opening the exhaust valve 4, and a duct 21 through the abutment controlled by the exhaust valve and an operating member adapted to control the abutment through the springs 45, 46 to apply and release the brakes. The driver's valve may be used to control the train pipe of an automatic system. Movement of the driver's handle 54 operates a screw member 51 to compress the springs 45, 46 and force down the piston 18 to close the exhaust valve 4 and open inlet valve 3 to connect the compressed air pipe 11 to brake cylinder pipe 14. The compressed air acting on piston 18 closes the valve 3 to lap position. Graduated application and release are obtained the pressure acting on piston 18 reclosing the valves at each stage and also maintaining the pressure at that set by the driver. The screw member 51 acts on the springs 45, 46 through a cup and ball 61, thimble 48 and collar 44. The springs are under initial tension by means of bolt 41 and nut 43 bearing on the collar 44. A pin 68 having roller 69 limits extreme movements of handle 54 and also prevents handle being removed except in full brake application position, by means of slot through which roller passes. The handle also carries a collar over which hangs a lug adapted to register with a slot in the collar when the handle is to be removed. A spring catch engages a slot in the screw member 51 in this position of the driver's valve to prevent unauthorized or accidental movement thereof. A screw pin 63 covered by removable cap 66 locks the handle 54 on a square extension of the screw member 51. The driver's valve is shown in combination with a double ended straight air brake system for a tram-car provided with conductor's emergency valves for connecting the compressed air pipe to the brake cylinder through reducing valves and a shuttle valve which closes the connection of the driver's valve to the brake cylinder when the conductor's valve is operated and vice versa. Two reservoirs are used in series from the compressor the pipe between the reservoirs is connected to a safety valve and a compressor governor. The two driver's valves one at each end of the car are connected to a tram check valve which closes one driver's valve from the brake cylinder when the other is connected to the brake cylinder. The check valve comprises two valves 119, 119<a>, Fig. 6, having the stems 125 abutting. The valves 119, 119<a> are forced over to one side or the other when the driver changes ends. On removing his handle from one end a pressure in excess of the normal maximum is produced in the pipe, 95 or 95<a> from one driver's valve or the other, owing to the fact that the slot engaging the pin 68, Fig. 1, slopes and turns the driver's valve as the handle is removed. The driver places his handle on the other valve and moves this to release whereupon the valves 119, 119<a> move to the other end position. A quick release valve, Fig. 8, is connected at 135 to the brake cylinder which is supplied through a ball valve 144 carried in a piston 138 which is raised by the flow of air to the brake cylinder. When the brake is released the pressure falls below the piston and the brake cylinder is connected to exhaust outlet 136. In partial release, when pressure above the piston 138 becomes less than that below it, the valve recloses. The driver's valve handle 54 and screw 51 may be replaced by a foot pedal.