Patent GB-253613-A (GB)
Title: Improvements in or relating to fluid-pressure brake apparatus for vehicles
IPC: B60T13/26
Filed: 1925-03-20
Abstract: 253,613. Peters & Co., Ltd., G. D., and Porter, A. S. March 20, 1925. Fluid-pressure; skid.-Fluid-pressure brake apparatus is adapted by the operation of a single driver's valve to give a straight air application of either of two sets of brakes or a simultaneous application of both sets. In simultaneous applications, an emergency valve is operated by the venting of one of the pipes of the system and effects the rapid application of both sets of brakes or of one set, the application of the other set being in this case gradual. The two sets of brakes may be those acting respectively on the driving and trailing wheels of a locomotive, or the front and rear wheels of a, motor vehicle, or on the wheels and track in the case of a tramcar. The apparatus shown in Fig. 1 comprises a wheel brake cylinder 1 and track brake cylinders 2. The cylinders 2 are normally connected by pipes 32, 31, 7 and the cavity 33 in the emergency valve 4 to the driver's valve 3. The main reservoir 5 is connected to the chamber 24 of the emergency valve and by way of a port 28 in the piston of this valve -and a passage 26 in the valve seat and pipes 27, 8 to the driver's valve. This valve comprises a seat 11. Fig. 10, and a rotary member 12, Fig. 11, having ports and cavities as described below. The notched segment with which the usual spring-pressed member on the handle 18 of the valve engages to indicate to the driver the position of the handle or to hold it in position is made separate from the valve casing so that it may readily be removed when worn and is preferably made of hardened steel, as described in Specification 255,797, [Class 135, Valves &c.]. The valve may have the following positions.-(A), (G) simultaneous emergency apptication of both sets of brakes; (B), (F) service, application of wheel and track brakes, respectively; (C), (E) lap or holding positions for wheel and track brakes respectively; (D) release of both sets of brakes. Tne rotary valve member 12 has two cavities 15, 15<a> which in the release position (D) connects ports 6b, 7<b> in the valve seat 11 communicating respectively with the wheel and track brake cylinder pipes 6, 7, with ports 9<b>, 9<c> also provided in the valve seat and connected to the exhaust pipe 9. which is provided with a silencer 10. In position (B) a service application of the wheel brakes is effected by bringing one or both of the small ports 14a in the valve member 12 into register with the port 6<b>. Air is then supplied to the cylinder 1 from the main reservoir .5 by way of the passage 26 in the emergency valve, pipe 8, chamber 3 of the driver's valve, and pipe 6. In position (F) a service application of the track brakes is similarly effected by way of ports 14<b>, 7<b>, pipe 7, cavity 33 of the emergency valve, and pipe 32. Simultaneous application of both sets of brakes may be effected by moving the driver's valve member 12 to position (G) to register the large ports 14, 7b so that air flows rapidly from pipe 8 to pipe 7, and the emergency valve moves to the left, closing the passage 26 and uncovering the port 30, through which air can then now directly from the main reservoir to the pipe 32 and the track brake cylinders 2. In this position of the driver's valve small ports 14<c>, 6<c> are also in register so that air is gradually supplied to the wheel brake cylinder 1 through the port 28 in the emergency valve piston and pipes 8, 6. If emergency application is made by moving the driver's valve to position A, ports 14 and 6<b> register and pipe 8 is vented to pipe 6, the rapid supply to the track brake and the gradual supply to the wheel brake being effected as before. In a modification, the connections are so arranged that the emergency valve connects the main reservoir directly to the wheel brake cylinder instead of to the track brake cylinder, and in a further modification both the wheel and track brake cylinders are so connected by the emergency valve.