GB482428A - Improvements in or relating to controlling devices for fluid pressure brakes - Google Patents

Abstract

482,428. Fluid - friction brakes. KNORR-BREMSE AKT.-GES. Oct. 4, 1937, No. 26805. Convention date, Oct. 13, 1936. [Class 103 (i)] Controlling-device for fluid-friction brake including a pump comprises housing 3 connected to the pressure chamber of the pump by a conduit 1 and to the suction chamber by a conduit 2 and containing a piston valve 4 having a flow aperture 5 adjusted in position automatically according to the speed of the part to be braked in such a way that the pump always works against the same pressure in spite of the fall of speed of the pump as the brake takes effect. To apply the brake, the pump is clutched to the rotating part to be braked and forces fluid under pressure through conduits 1, 2 and aperture 5 and also past a valve 7, through conduits 11, 14 above the piston valve 4 which it depresses so as to restrict the passage between the conduits 1, 2. The pressure fluid also flows through conduits 11, 16 by depressing a piston valve 13 and below the piston valve 4, which in view of the restriction of area of its upper surface by the rod 6 is raised and reopens the aperture 5. Thus, as the speed diminishes, the pressure of the fluid is unable to depress the piston valve 13 in order to pass beneath the piston valve 4 and therefore the pressure above the valve 4 depresses it to a gradually increasing extent. The force against which the fluid acts to depress the piston 13 is supplied by differential fluid pressure acting on a diaphragm 23 and adjusted by means of conduits 24, 25. The underside of the valve 4 is relieved of fluid by a throttle device 18, which fluid flows partly to the suction pipe 2 by a conduit 20 and a valve 10 and partly flows to a reservoir 22. The coiiduits 15, 19 and valves 8, 9 are provided for the other direction of rotation of the pump.