Patent GB-237247-A (GB)
Title: Improvements relating to pneumatic brakes for railway trains
IPC: B60T13/26
Filed: 1925-07-10
Abstract: 237,247. Moutier, A. E. July 18, 1924, [Convention date] Fluid-pressure.-Each vehicle of a train is fitted with an automatic compressed-air brake, a direct-acting vacuum brake, and it may be with a direct-acting high pressure brake, a single train pipe being used to control the three brakes by means of three driver's valves, each adapted to control one of the brakes. The automatic brake compries, as usual, a triple valve 4, brake cylinder 5, and auxiliary reservoir 7, Fig. 6, whilst the vacuum brake comprises a brake cylinder 8, the pistons 15, 13 of the two brakes being connected to a common piston rod 14, and the dimensions of the piston 13 being such that the action of the vacuum brake will be as powerful as that of the automatic brake. The train pipe 1 is connected through the high-pressure brake valve 10 and a pipe 16 to a valve device 12, Figs. 6 and 10, comprising chambers 19, 20, 21. A spring-pressed diaphragm 29 separates the chambers 20, 21, and a spring-pressed diaphragm 28 separating the chambers 19, 21 has a stem 27 which carries a pair of valves 22, 24, of which the valve. 22 governs communication between the pipe 16 and a pipe 23 leading to the triple valve 4, and the valve 24 governs communication between the chamber 21 and a chamber 25 connected through a valve 30 to a pipe 26 leading to the vacuum brake cylinder 8. A slide valve 36, connected to the stem 27, controls communication between a pipe 33 leading from the pipe 26 and passages 34, 35 leading respectively to atmosphere and to the chamber 25. The chamber 20 is connected by a pipe 17 through a cock 18 to the pressure supply pipe 39 of the cylinder 5. When the train pipe is fully charged, the parts of the valve device 12 take up the position shown in Fig. 10, the valve 22 being open so that the auxiliary reservoir 7 is charged past the triple valve 4, and the brake cylinder 5 is connected to atmosphere through the pipe 39 and the triple valve exhaust. The valve 24 cuts off the chamber 21 from the chamber 25, and the vacuum brake cylinder is connected to atmosphere through a non-return valve 32, and the pipe and passage 33, 34. On a reduction of pressure in the train pipe, the triple, valve 4 connects the auxiliary reservoir 7 to the brake cylinder 5, and the brakes are applied. Brake cylinder pressure is also transmitted through pipe 17 to chamber 20 and raises the diaphragm 29, the stem of which engages the stem 27 to prevent any downward movement thereof. In these circumstances, the valve 24 remains closed, and the vacuum brake is not available, this arrangement being adopted for unloaded vehicles. On a loaded vehicle, however, the cock 18 is turned to cut off the pipe 17 from the pipe 39 and connect it to atmosphere. In an application of the brakes by compressed air, the diaphragm 29 therefore remains in its lowest position, and the diaphragm 28 is free to descend to open the valve 24, the valve 22 being finally closed, when the pressure in the chamber 21 has fallen sufficiently. The slide valve 36 also descends to close the outlet 34 and connect the chambers 21, 25 also through the passage. 35, the valve 30 being closed by the pressure in the chamber 25 and thereby preventing the passage of pressure air to the cylinder 8. The venting of the train pipe into the chambers 25 of each valve 12 ensures rapid action of the brakes throughout the train. If now the vacuum driver's brake valve is opened to exhaust the train pipe, the valve 30 is opened and the brake cylinder 8 is exhausted, and supplements the action of the brake cylinder 5. On destroying the vacuum in the train pipe, the vacuum brake cylinder is thrown out of action, and on restoring the normal pressure therein the diaphragm 28 is raised to close the valve 24 and open the valve 22. The triple valve then moves to release position to effect complete release of the brakes. The high-pressure brake comprises a cylinder 43, Fig. 7, the piston rod 9 of which carries a shoe 46 adapted to engage a collar 45 on the wheel axle, connected to the pressure supply pipe 50, leading to the valve 10, through a non-return valve 53, and to a second pipe leading to a port 51 in the valve 10, Fig. 12, normally connected to an exhaust port 52. A spring-pressed, piston slide valve 49 connects the train pipe 1 to the pipe 16 at normal pressures, but if the high-pressure driver's brake valve is operated to supply highpressure air to the train pipe, the valve 49 rises to cut off the pipe 1 from the pipe 16 and connect it to the pipe 50. At the same time the port 51 is cut off from the exhaust port 52. The brake cylinder 43 is therefore charged through the valve 53. The tendency of the high pressure in the cylinder 43 to raise the vehicle body is obviated by straps 54 carrying a shoe 55 which engages the collar 45 a.s soon as the body begins to lift. On reducing the train-pipe pressure to its normal value, the valve 49 returns to its lower position and the cylinder 43 then exhausts through the ports 51, 52. The brake cylinder may, however, be vented to the brake cylinder 5, and the collnr 45 may be eccentrically mounted on the axle.