GB285142A - Improvements in and relating to fluid pressure braking apparatus - Google Patents

Abstract

285,142. Tomlinson, A. V., (Compagnie des Freins Westinghouse). Nov. 10, 1926. Fluid-pressure.-Fluid-pressure braking apparatus is provided with a regulating valve device controlling simultaneously the release of fluid from the brake cylinder and the supply of fluid to charge the auxiliary reservoir so as to maintain strict proportionality between the variations of pressure in these two parts. The regulating valve comprises a piston 19, Fig. 2, subject on one side to the pressure of springs 25 and on the other to the pressures in chambers 11 ,20. The pressure in chamber 11 is due to the fluid flowing from the triple valve through a port 45, an aperture 10 in a slide valve 5 and passing through a port 15 to charge the auxiliary reservoir. The pressure in the chamber 20 is due to the exhaust of fluid from the brake cylinder through the triple valve, a port 7 and a cavity 12 in the slide valve 5 from whence it flows through a port 13 to an exhaust outlet and this pressure is communicated by a passage 21. If the total pressure on one side of the piston due to the pressures in the brake cylinder and the auxiliary reservoir differs from that of the springs 25 the slide valve is moved to cut off one or other of the fluid supplies. In case of rupture or too great compression of the springs 25 the slide valve moves to the right to uncover the port 45 and the cavity 12 maintaines communication between ports 13, 7 thus ensuring continuity of the two supplies. The port 45 has a cross sectional area substantially equal to that of the usual feed groove. The pressure of springs 25 is regulated by an element 18 secured by a.n element 26 carrying a rod 47 acting as an abutment for the piston 19 on moving to the right. In a modification of the invention the reservoir pressure in the chamber 11, Fig. 3 acts on one face of a piston 31 and the brake cylinder pressure in the chamber 36 acts on one face of a piston 32, each piston controlling one of the superposed slide valves 33, 34. The pistons are subject on the opposite faces to the pressure of springs 35, 38. As long as the pressure variations are proportional the pistons and slide valves move to the left together otherwise the distance between the pistons varies and one or other of the fluid supplies is cut off- When the reservoir is fully charged, the slide valves are on the extreme left and fluid for the reservoir can flow through cavity 43 as well as aperture 10 and the brake cylinder is connected to atmosphere through cavities 42 and 44 as well as cavity 12 and aperture 41. Adjusting elements 28, secured by elements 30, are provided. Rotary flat or cylindrical valves may be used in place of the slide valves.