US 4,494,571 AGranted

Electropneumatic door control valve

AssigneeWABCO Fahrzeugbremsen GmbH

InventorsGunter Seegers, Gunter Sebesta, Alfred Klatt

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Abstract

An electropneumatic door valve for use with pneumatic door operations as are used on mass transit vehicles. The single valve housing arrangement provides either a through passageway or a throttled passageway for pressurizing the opening or closing chamber of a pneumatic door drive unit. Provisions are also made to allow automatic reversal should the door become wedged, and to allow manual override should that operation be desired. Electrical pulses initiated by the vehicle operator trigger one of two solenoid valves which direct one of two operating pistons into a position to dictate which passageway will be established. Three vent passageways are provided to exhaust compressed air from any of the chambers which had been charged during a previous door operation.

Claims8

Dependent claims

An electropneumatic door control valve for controlling a flow of compressed air from a compressed air source to at least one of an opening and closing chamber of a pneumatic door drive where the door drive includes an emergency cock for tripping a pilot valve to divert the compressed air, which comprises:

(a) a housing having a primary inlet and a first and second control outlet;
(b) first and second operating valves located within said housing, each of said operating valves having a first and a second operating position;
(c) a first through passageway formed in said housing between said primary inlet and said first control outlet and including therebetween, said first and second operating valves in respective first operating positions;
(d) a first solenoid valve means for selectively communicating the outlet of said first operating valve to said second control outlet;
(e) a second through passageway formed in said housing between said primary inlet and said second control outlet and including therebetween said first operating valve in such first operating position;
(f) a second solenoid valve means for urging said second operating valve into such first operating position;
(g) a throttled passageway communicating said primary inlet to the outlet of said first operating valve;
(h) a secondary inlet communicating with the pilot valve and being effective when the pilot valve has diverted such compressed air from said primary inlet to said secondary inlet;
(i) a first and second piston spool located in and forming a part of respective said first and second operating valves;
(j) a double check valve for allowing the higher of two pressures between said second through passageway and said secondary operating valve;
and
(k) a biasing means for urging said first piston spool of said first operating valve into the second operating position.

9 more elements

Dependencies are inferred from the claim text.