Patent GB-190500307-A (GB)
Title: Improvements relating to Fluid Pressure Brakes.
Filed: 1905-01-06
Granted: 1905-10-26
Abstract: 307. Westinghouse Brake Co., and Rendell, A. W. Jan. 6. Brakes.-In a pneumatic-pressure brake system in which an auxiliary cylinder with its own triple valve is used on each car, in addition to the ordinary brake cylinder, for applying additional pressure to the brakes at high speeds, a valve is provided which, during service applications of the brake, cuts off the auxiliary cylinder from its triple valve independently of the speed of the train, but, when emergency applications are made, controls either the admission or the exhaust, or both the admission and the exhaust, in accordance with the speed of the train, a centrifugal governor or dynamo driven from the axle, or other means, being employed to operate the valve. In one arrangement of the valve, shown in sectional elevation and plan in Figs. 3 and 4, the supply pipe 2 from the triple valve is connected to a chamber 1 containing a valve 7, which normally connects a pipe 6, leading to the auxiliary brake cylinder, to an exhaust port 13, and which is operated by a spring-controlled piston 9 to shut off the exhaust from the pipe 6 to the port 13 and connect the pipe 6 to the chamber 1 when the air in the chamber 1 attains a certain pressure. This device may be used alone to control the auxiliary brake cylinder, a leak-off opening being made in the pipe 6 to allow the pressure to leak off as the train slows down. In the arrangement shown, however, the leak-off is controlled by a centrifugal governor 29, Fig. 4, carried by the rod 19 of the piston 9 and arranged to be driven frictionally by the running axle 39 of the car when the pressure in the chamber 1 is sufficient to open the valve 7. A flexible pipe 17 connects the brake-cylinder pipe 6 with a valve chamber 36 containing an exhaust valve 14, which is connected to a diaphragm 34 and is held closed by the governor 29 until the speed is reduced to a certain limit. The valve then opens and exhausts the auxiliary brake cylinder to atmosphere. The rod 19 is steadied by a guide-stud 20. The governor is driven by a rawhide wheel 26. In a modification, Fig. 5, the valve 7 is dispensed with and the chamber 1 is always in communication with the chamber 36 by a small hole 46 and a passage 41 in the rod 19. When the pressure reaches a certain limit, the inner end of the rod 19 moves away from a plug 44, and a clear passage is opened from the chamber 1 to the chamber 36 and by the pipe 17 to the brake cylinder. The governing-valve remains the same as shown in Fig. 4. In another modification, Fig. 7, the governor, acting against a spring 52, controls both an admission valve 47 and an escape valve 49, the former being opened at high speeds and the latter at low speeds. With this arrangement a non-return valve is preferably placed between the valve 47 and the brake cylinder, and a leak-off opening is provided between the non- return valve and the cylinder. A dynamo 62. Fig. 8, and an electro-magnet 56 may be used instead of the centrifugal governor. The dynamo may consist of a star-shaped permanent magnet 58 rotating in front of soft-iron cores 62 suitably coiled. The inner end of the rod 19 may act as a valve in conjunction with a hollow plug 53. The outer end is given additional support by a cylindrical extension 64 fitted with a door 66 for giving access to the adjusting-nut 65 of the spring 11.