Improvements relating to distributors for braking apparatus

摘要

1,021,952. Fluid-pressure brakes. WESTINGHOUSE BRAKE & SIGNAL CO. Ltd. Sept. 15, 1964 [Oct. 3, 1963], No. 38999/63. Heading F2F. A distributer for fluid-operated braking apparatus comprising a quick service valve formed by a valve member and a biased seat member, a main distributer pile arranged to move the valve member, latching means arranged to constrain the seat member, the arrangement permitting the latch means to disengage and allow the seat member to follow up and close the quick service valve upon a degree of brake application obtaining, is characterized in that the latch means and seat member interengage in at least two positions of the said distributer pile. In the embodiment shown, a main pile comprises a stem 24 carrying a main diaphragm 14, subject to brake pipe pressure (BP) and control reservoir pressure (CR) at its upper and lower surfaces respectively, and a diaphragm 20, subject to brake cylinder pressure (BC) and atmosphere (At) at its respective upper and lower surfaces. The stem carries a quick service valve member 18 engageable by a reciprocably-mounted, spring-biased, seat sleeve member 17 having shoulders or steps 15, 16 engageable by the nose 12 of a pivoted bellcrank latching means 9 which is controlled by the stem 8 of diaphragm 4 subject to brake cylinder (BC) and atmospheric pressures. Said diaphragm 4 additionally controls a ball valve 1 in a connection between the control reservoir and brake pipe, said connection also including a choke 2 and a restricter valve 5 mounted on the main diaphragm. A small capacity by-pass choke 6 provides stability of the distributer in the event of minor brake fluctuations. On brake application, the pile moves upwards from the full release position shown and the quick service valve member 18 unseats to vent the brake pipe to atmosphere until the brake cylinder pressure builds up on diaphragm 4 to pivot the latch 9 and release the seat member 17. If on brake release, the brake pipe pressure is built up slowly and the pile is not in the full release position when the control charging valve 1 has opened, it is essential, if re-application of the brake is to be made, to ensure that either valve 5 is closed or the latch is re-engaged in order to prevent flow back from the control reservoir to the brake pipe and to retain the quick service action. Step 15 corresponds to this partial release position, said step being engaged by the latch on brake release prior to the valve 5 opening thereby reducing the range of movement of the pile when the valve 5 is open and quick service is not available.