Clark Equipment Compnay

Jason R Coombs

Thomas J Tokach

Charles Young

Joseph A St Aubin

Rodney Koch

Jonathan Lacher

Jonathan J Lacher

Joseph A Aubin

Disclosed embodiments include hydraulic systems which provide power to lift, tilt and auxiliary (e.g., implement) functions, including high-flow auxiliary functions, with increased efficiency. Disclosed embodiments incorporate a single variable displacement pump that supplies pressurized fluid to a main control valve (e.g., for lift, tilt, and auxiliary functions) and a bypass circuit. The main control valve supplies fluid to control lift, tilt, and auxiliary flow for implements. The bypass circuit combines flow with the output of the auxiliary section of the main control valve to optionally provide high-flow for selected implements. The single variable displacement pump can then be set to different output flow levels, with the bypass circuit functioning differently under different conditions to optimize hydraulic flow to carryout various tasks under various conditions.

Hydraulic bypass circuit

Valve assemblies are provided in a track tensioning system or in other applications. The valve assemblies allow pressurized fluid (grease or hydraulic fluid from a power machine) to be introduced or evacuated from the same port. The valve assemblies use either a single check ball or poppet configuration, or a dual check ball or poppet configuration which are moveable from a first configuration, in which fluid is blocked in one direction while allowing flow in the other direction, to a second configuration where the reverse is true. A track tensioning element includes piston retaining features which retain a piston within a track tensioning cylinder tube. A track tensioning element can also include a no-pre-load spring positioned in-line with the tensioning cylinder. Disclosed track tensioning systems and track tensioning elements can, in various embodiments, utilize any combination of all or some of the disclosed features.

Track tensioner

A power machine and a power conversion system for a power machine are disclosed. In an exemplary embodiment, the power conversion system includes a pump configured to provide a source of pressurized hydraulic fluid and a control valve assembly to receive the hydraulic fluid. The control valve assembly includes a first valve element configured to direct hydraulic fluid to an actuator when the first valve element is in first and second actuated positions. The control valve assembly also includes a second valve element downstream of the first spool. The first valve element is moveable between an unactuated position and the first and second actuated positions and is configured to direct hydraulic fluid received from the actuator through the second actuated position to the second valve element and to direct hydraulic fluid received from the actuator through the first actuated position to bypass the second valve element.

Control valve assembly

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Bismarck, ND, United States of America

Jason R Coombs