GB215079A - Improvements in or relating to fluid-operated braking systems - Google Patents

Abstract

215,079. Alley, S. E. Jan. 31, 1923. Fluid-pressure.-The vacuum in a vacuum brake system reacts through a piston upon the pedal or other operating member whereby the operator receives an indication of the force applied to the main braking piston. The piston may control the exhaust connection to the brake cylinder, an air inlet release valve and a steam supply valve for an ejector by which the vacuum is produced. Specification 4171/14 is referred to. The rod 26 coupled at 27 to a foot lever pivoted in a casing 10 carries a piston 25 sliding in a casing 14 which is permanently in communication at its upper part with the brake cylinder and has also a port 23 leading to -the exhaust passage of a steam ejector. The rod 26 is adapted to engage with its end 36 a valve 38 by which air can be admitted through ports 37 to the casing 14 and has a cam face 30 for actuating the stem 31 of a valve 19 which admits steam to the ejector through the connections 17 and 21. As seen in the drawing the pipe 21 passes behind the upper part of the casing 14 to the ejector. The parts are shown in the release position, the piston being held in its upper position by a spring 28 whereby the air valve 38 also is lifted and' the brake cylinder open to atmosphere. If the foot lever is depressed the valve 38 is closed and the port 23 and steam valve 19 are opened to exhaust the brake cylinder the vacuum in which, since the piston 25 is subject thereto, reacts upon the foot levers.