Parker-Hannifin Corporation

Brewce Larkin

Daniel Dyminski

A variable displacement hydraulic pump including a control actuator configured to interact with a movable displacement control member to control the displacement of the pump; and a displacement control valve assembly configured to provide mechanical feedback control of positioning of the control actuator and thereby the displacement control member. The displacement control valve assembly includes a control valve member that is movable within a fluid flow path of the control valve assembly to control a flow of fluid to or from the control actuator. The control valve assembly includes a first valve part, a second valve part, and a biasing member configured to selectively position respective one or more portions of the first and second valve parts relative to each other to open or close a vent flow passage in response to an operating state of the pump. When in a normal operating state of the pump, the biasing member is configured to position the first and second valve parts relative to each other such that the vent flow passage is closed, and the control valve member moves in the fluid flow path to control the flow of fluid to or from the control actuator. When in a failsafe state of the pump, the biasing member is configured to position the first and second valve parts relative to each other such that the vent flow passage is opened, thereby enabling fluid from the control actuator to escape via the vent flow passage.

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Everett, WA, United States of America

Brewce Larkin