GB204086A - Improvements relating to vacuum brake apparatus for railway and like vehicles - Google Patents

Abstract

204,086. Gresham, H. E., and Kiernan, G. May 19, 1922. Fluid - pressure. - Rapid-action valves for vacuum brakes adapted to operate at each successive admission of air to the train-pipe, by the driver to effect a partial application of the brakes, have a restricted passage between the train-pipe and the control chamber for preventing operation of the valve by a gradual admission of air to the train-pipe by the driver, a larger passage being opened for admitting air to the chamber when the valve is opened and for effecting the rapid exhaustion of the chamber when the valve is closed. As shown in Fig. 1, the valve a has a central aperture within which is disposed a fixed plug or partial closure-piece b having a central passage controlled by a ball-valve d. If air is admitted rapidly for a short period to the train-pipe e by the driver, the valve a lifts to admit further air by the inlet h. In the raised position of the valve a larger passage through the valve is provided around the piece b. When the valve re-closes vacuum is rapidly re-established in the control chamber c by way of the valve d. In the construction shown in Fig. 2, a passage f is provided between the train-pipe and the control chamber c and is controlled by a non-return valve d which opens automatically to establish the vacuum in the chamber and is opened by the stem of the valve a when that valve is open. A restricted passage g is provided in the valve d. Fig. 6 shows a valve d arranged in a central passage through the valve a, the valve d opening automatically against the action of a spring i when there is a superior pressure in the chamber c and being opened by a stop w when the valve a is opened. In a further construction, a partial closure-piece resembling that shown in Fig. 1 but without the passage and ball valve is mounted on a spring so that it is withdrawn downwardly through the aperture in the valve a to provide a larger passage through the valve when there is a superior pressure in the chamber c.