Patent GB-441392-A (GB)
Title: Improvements relating to fluid pressure braking apparatus
IPC: B60T8/32
Filed: 1934-07-19
Abstract: 441,392. Fluid - pressure brakes. TOMLINSON, A. V., 65, Victoria Street, Westminster.-(Compagnie des Freins Westinghouse; Sevran, France) July 19, 1934, Nos. 21159 and 23165. [Class 103 (i)] Fluid-pressure brake apparatus comprises a triple or like valve adapted to supply and exhaust a brake cylinder in response to variations in brake pipe pressure and a relay valve operated to permit the supply to a cylinder under the control of pressure fluid admitted by a speed influenced valve opposed to another fluid pressure, the relay valve cutting-off the supply when the opposed pressures are equal and being adapted to permit the gradual release of pressure fluid from the cylinder as the pressure controlled by the speed influenced valve is reduced. According to Fig. 2, when the pressure supplied by the auxiliary reservoir 5 through the triple valve 4 to the brake cylinder 6 by reduction of the pressure in the brake pipe 3 reaches a certain value, this pressure acting through the pipe 30 upon the spring-pressed piston 32 of a valve device 13 depresses this piston and then acts through pipe 39 upon the piston 36 of a valve device 31 so as to open a valve 38 to supply pressure fluid from an additional reservoir 15 to a relay valve 8. The reservoir 15 is supplied at a higher pressure than that of the reservoir 5 from the main reservoir pipe 17. The relay valve 8 comprises a chamber 21 connected through pipe 22 and double-check valve 18 to the cylinder 6 and adapted to be connected by valves 23 and 27 operated by the piston 19 either to the atmosphere by passage 25, as shown, or to a supply chamber 26. When the valve 38 is opened the reservoir 15 is connected by pipes 43, 44 to the chamber 26 and through a governor controlled valve 14 to the piston chamber 20. A pressure dependent upon the speed is thus established in the chamber 20 and consequently also by the opening of the valve 27 in the chamber 21, and if this pressure exceeds that already established in the cylinder 6 by the triple valve the checkvalve 18 moves over and the additional pressure is added to the cylinder. As the speed falls, the valve 23 connects the cylinder to atmosphere until the initial pressure therein is reached. Fig. 1 shows a system in which in addition to the usual cylinder 6, triple valve 4 and auxiliary reservoir 5, a supplementary cylinder 9 adapted to be supplied from an additional reservoir 7 supplied from the brake pipe 3 through a non- return valve 10, is provided. The chambers 21, 26 of the relay valve 8, which is similar to that of Fig. 2, are connected respectively to the cylinder 9 and reservoir 7 and the chamber 20 is connected through the speed controlled valve 14 and a pressure controlled valve 13, similar to that of Fig. 2, to the cylinder 6. Thus when the pressure in the cylinder 6 reaches a value sufficient to open the valve 13, a pressure modified in accordance with the speed is established in the chamber 20 of the valve 8 and thus in the cylinder 9. According to Fig. 4, the supplementary cylinder 9 is supplied through an additional triple valve 49 from an additional reservoir 50. A further reservoir 51 normally supplied through a passage 56 in the triple valve, but isolated thereby in the application position, supplies the control pressure for the relay valve 8 modified by the speed controlled valve 14. The reservoir 51 may be dispensed with, the reservoir 50 being connected to the valve 14 as well as to the supply chamber of the valve 8. According to Fig. 5, the relay valve 8 is controlled by the pressure in the primary cylinder which is supplied by the usual triple valve and is connected to the piston chamber 20 of that valve by pipe 29 and establishes pressure in a supplementary cylinder 61 which is connected to the chamber 21. The pressure in the supply chamber 26, however, is supplied from a separate reservoir through pipe 47 and the speed controlled valve 14. If, therefore, during an application the pressure in chamber 26 is less than that in the cylinder 6, the valve 27 will remain open and the pressure in cylinder 61 will fall with the speed. The speed controlled valve shown in Fig. 5 comprises a piston 65 subject to the opposing pressures of centrifugal masses and of the fluid pressure in pipe 48 and chamber 26 of valve 8. The piston operates supply and exhaust valves 62, 63 and thus establishes a pressure in the chamber 26 in accordance with the speed. As the valves 62, 63 may not be of sufficient capacity to supply the chamber 26 and cylinder 61 directly, these valves may control an additional relay valve which supplies this chamber.