Westinghouse Air Brake Company

Trevor A Scott

Ulf Stahmer

Albert A McKay

Eric G Smith

Jeffrey D Reid

Stanley J Pasek

W Thomas Digweed

David A Porteous

An apparatus incrementally reduces pressure in a first volume in response to an increase in pressure in a second volume. A valve body defines a bore that houses a piston and supply and return passages that communicate with first and second ends of the bore, respectively. The valve body also defines a release passage that connects the bore with the first volume and an exhaust passage that connects the bore with atmosphere. An inlet valve opens when pressure in the second volume increases relative to pressure in the supply passage. An outlet valve opens when pressure in the second volume decreases relative to pressure in the return passage. The piston is biased in a closed position against the first end and defines a passageway through which the first and the second ends communicate. When pressure increases in the second volume, the inlet valve opens causing the first end to pressurize and move the piston to an open position in which the release and exhaust passages communicate. This allows the first volume to vent gradually to atmosphere. As the pressure gradually equalizes between the first and second ends via the passageway, the piston returns to its closed position thereby discontinuing communication between the release and exhaust passages so that the first volume is cut off from atmosphere. When pressure decreases in the second volume, the outlet valve opens causing pressure to equalize between the supply and return passages via the passageway and to approximate the pressure in the second volume.

Graduated release valve

In a conventional spool valve, the nut holding the diaphragm to the spool valve stem is replaced by a retaining ring, thereby simplifying the machining operation and eliminating the problems caused by damaged threads. A good seal is nevertheless achieved by providing an insert molded diaphragm having a bead around its axial aperture, which is compressed against the radial flange of the valve stem, and such that the retaining ring will maintain the compressed condition of the bead against the radial flange to maintain a good seal.

Spool valve assembly

A test connector for connecting an air brake test device to access ports of an air brake control valve device where such access ports are normally closed by check valves. A plurality of actuator devices corresponding in number to the access ports are provided in the test connector to unseat the check valves and conduct test air to the test device via central passages in the actuators. The actuators are piston operated in response to a pilot pressure received from a source of compressed air remote from the connector.

Test connector for accessing compressed air at test ports of a railroad

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Gimbsy, Canada

Trevor A Scott