US 4,105,041 AGranted

Hydraulic system

AssigneeFichtel & Sachs AG

InventorLudwig Axthammer

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Abstract

A hydraulic system suitable for supplying fluid under pressure to the brakes and other elements of an automotive vehicle includes a valve casing formed with a first port, normally connected to a pump, a second port normally connected to a fluid storage vessel and the vehicle element to be supplied, and a third port leading to a sump. A valve slide moves in the casing and defines therewith a conduit. The conduit connects the first and third ports in a first slide position and is closed in a second slide position. A spring-loaded check valve connects the first and second ports only when the fluid pressure in the first port is higher than in the second port. A spring permanently biases the valve slide toward the second position while the fluid pressure in the second port tends to move the slide toward the first position. The biasing force of the spring decreases during movement of the valve slide from the second toward the first position.

Claims11

Dependent claims

A hydraulic system comprising:

(a) a valve casing formed with first, second, and third ports;
(b) a valve member movable in said casing between a first position and a second position,
(1) said valve member and said casing defining a conduit connecting said first and third ports in said first position of said valve member, said valve member closing said conduit in said second position of said valve member;
(c) check valve means connecting said first and second ports in response to fluid pressure in said first port higher than the fluid pressure in said second port while disconnecting said first and second ports when the fluid pressure in said second port is higher than in said first port;
(d) yieldably resilient means permanently biasing said valve member to move from said first to said second position thereof;
and
(e) means on said valve member responsive to pressure of fluid in said second port for moving said valve member from said second position toward the first position thereof against the biasing force of said yieldably resilient means,
(1) said force decreasing during a portion of said movement of the valve member from said second position toward said first position.

5 more elements

Dependencies are inferred from the claim text.