GB364453A - - Google Patents

Abstract

364,453. Fluid - pressure brakes. KNORR-BREMSE AKT.-GES., 9, Neue Bahnhofstrasse, Lichtenberg, Berlin. April 2, 1931, No. 10113. Convention date, Feb. 28. [Class 103 (i).] In control valves for r fl u i d pressure brakes of the kind .comprising a valve operating piston subject to the brake cylinder pressure and operated through a spring by the control lever, so that each position of the control lever gives a definite braking pressure, the valve is of piston form and it and the control piston are provided with bellows-like sleeves to prevent leakage past the sliding surfaces. The device comprises chambers b, c communicating respectively with the compressed air reservoir and the brake cylinder. A valve body d slidable in the casing a against a spring f has an annular part h forming the inlet valve and a part k, m forming the outlet valve co-operating with an aperture l in a sleeve or piston m which slides in the fixed parts n, o. A spring q engages a ring p projecting from the sleeve m to urge it downwardly. A spring r is disposed between the sleeve and a piece s engaged by the operating lever u. A passage i connects the chamber c to the upper side of the valve body d. 'With the parts in the normal position shown, the brake cylinder is exhausted through the passages l, y. When the lever u is moved to the right, the sleeve m is moved by the spring r to seat the outlet valve k and open the inlet valve h and compressed air flows to the brake cylinder until the pressure therein acting upon the upper surface of the sleeve m is sufficient to overcome the spring r when the valve h recloses. The brake cylinder pressure is dependent upon the degree of compression of the spring r when the valve h closes and thus upon the extent of movement of the lever u. Corrugated spring or bellows-like sleeves v, x prevent leakage of air from the chamber b to the chamber c and from this chamber to the atmosphere respectively, past the sliding cylindrical surfaces of the valve d and piston m.