US 5,503,467 AGranted

Pneumatic emergency backup for electro-pneumatic freight brake

AssigneeWestinghouse Air Brake Company

InventorEdward W. Gaughan

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Abstract

A backup pneumatic emergency control valve for an electro-pneumatic brake system for a railroad freight car comprising an emergency portion of a standard AB type freight brake control valve device without the service portion. In the absence of a service portion in which the release function of an emergency brake application is normally provided, the emergency portion is modified to achieve this release function in one embodiment by venting the inshot valve control chamber to which brake cylinder pressure is typically connected via the high pressure spool valve during brake pipe recharge following an emergency brake application; and in another embodiment by replacing the accelerated emergency release check valve with a plug to isolate brake cylinder pressure in a backdump passage from the brake pipe and venting the check valve cavity to provide a means of exhausting brake cylinder pressure via the backdump passage when the backdump spool valve is moved to release position by the emergency piston during brakepipe recharge following an emergency brake application.

Claims10

Dependent claims

A pneumatic backup brake arranged with an electro-pneumatic brake for a railroad car having a brake pipe charged with fluid under pressure, brake means, an emergency reservoir, and a control valve including a quick action pressure chamber, said emergency reservoir and said quick action pressure chamber being charged via said brake pipe, wherein said control valve device comprises:

a. a first flow path via which fluid under pressure is connected from said emergency reservoir to said brake means;
b. a second flow path via which fluid under pressure is released from said brake means to atmosphere;
c. valve means having a first operable condition in which said first flow path is established and said second flow path is interrupted in response to an emergency rate of reduction of said brake pipe fluid pressure and a second operable condition in which said first flow path is interrupted and said second flow path is established;
and
d. emergency means for effecting operation of said valve means to said second condition only in response to said brake pipe being recharged with fluid under pressure following a reduction thereof in accordance with an emergency brake application.

2 more elements

Dependencies are inferred from the claim text.