Sauer-danfoss Inc.

Deere + Company

Dennis O Courtright

Enzo Soncini

Davide I Davoli

John P Tow

David Leo Sigl

A relief valve for a hydraulic machine that combines a poppet valve assembly and a pilot valve assembly together using a connector pin wherein internal fluid passageways within the poppet and pilot spools provide a fluid flow path between the inlet of the valve and a cavity disposed between the poppet and pilot. As a result of the internal passageways fluid is metered to the interior cavity to provide additional control and stability within the relief valve.

Low pressure rise rate pilot operated poppet relief valve

A relief valve assembly. The relief valve assembly has a housing that houses a sleeve element that surrounds a spool that has a spring guide disposed therein and is biased away from the spool by a spring. A fluid flow path is created from a valve exit of the assembly through the sleeve and spool via a series of openings, grooves and orifices in at least one position of the relief valve assembly. The fluid flow path acts to reduce pressure rise rate.

Low rise rate direct acting relief valve

A selectable detent relief valve of this invention is used to operate a hydraulic detent mechanism on a manually operated spool valve. This design has three modes of operation, no-detent, continuous detent and kick-out detent. The no-detent position allows flow to pass through the relief valve, from a first port to a second port and bypass the relief function. The pressure created, disengages the detent mechanism in the spool valve. The spool always returns to neutral position as long as pressure is present. The continuous detent position blocks the flow from a first port to a second port. The kick-out detent position allows flow to pass from the first port to the second port to override (kick-out) the detent mechanism in the spool when the pressure is greater than 2600 psi.

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Easley, SC, United States of America

Dennis O Courtright