Clark Equipment Compnay

Doosan Bobcat North America Inc.

Bobcat Company

Daniel J Krieger

Thomas J Tokach

Kevin Joseph Zent

David Glasser

William H Curl

Jeffrey A Dahl

Michael D Wetzel

Dennis E Agnew

Matthew Kaldor

Troy D Kraft

Brent Durkin

Jason A Osborn

Scott J LaCoe

Benjamin Storhaug

Matthew Ryan Kettner

Darron Carr

Patrick P Lacher

Kevin J Miiller

Bernard Poncet

Frederic Lichtenberger

Thomas Tokach

Gunter G Matt

Caren A Loebs

Robert J Celley

Brent C Durkin

Matthew R Kettner

Darron J Carr

Scott Lacoe

Kevin J Miller

A lift arm assembly for a power machine can include a lift arm, an implement carrier, a lift cylinder that raises or lowers the lift arm, a leveling link, a tilt cylinder that causes the implement carrier to pivot relative to the lift arm, and an isolated hydraulic circuit. The isolated hydraulic circuit can include a follower cylinder that is mechanically synchronized with the lift cylinder, a leveling cylinder that can be pivotally secured to the leveling link and to the lift arm, a first conduit that can provide hydraulic flow between base ends of the follower and leveling cylinders, and a second conduit that can provide hydraulic flow between rod ends of the follower and leveling cylinders. Movement of the follower and leveling cylinders can be hydraulically synchronized by flow through the first and second conduits.

Self-leveling lift arm assembly for power machines

Disclosed embodiments include steering circuits utilizing a controllable cross-feed loop between left and right drive motor sides of an articulated power machine to reduce skidding caused by a turning operation in which an articulation actuator changes an articulation joint angle between a front frame member and a rear frame member of the power machine.

Traction control for steering articulated power machine

A power machine having a frame and a cab pivotally attached to the frame at a first cab pivot, such that the cab pivots about a first transverse axis from an operational position to a service position, includes a link mechanism and a first spring. The link mechanism includes a first link having a first link end, a second link end, and a first pivot engagement feature pivotally coupling the first link to the frame and to the cab such that the first link is pivotal about the first transverse axis. The second link end is configured to interface with the cab at a position forward of and below the first cab pivot and first pivot engagement feature when the cab is in the operational position.

Assist mechanism for moving cab on power machine

Tracked vehicles and drive systems for tracked vehicles including a guard or shield for a drive motor that deflects debris drawn into a space where the drive motor is located. The guard also provides a longer critical path between the outside of a drive motor assembly and an inside of the drive motor assembly.

Shield for drive motor

Disclosed embodiments include power machines, implement coupling systems and methods in which hydraulic or electric coupling between an implement and the power machine is made automatically using an existing actuator, for example a tilt actuator, of the power machine. Thus, additional actuators are not required to achieve hydraulic or electric coupling. In exemplary embodiments, power coupling is also free from the process of mechanically coupling the implement to the implement carrier. Also, in exemplary embodiments, a machine side coupler assembly moves with the implement after a connection is established, despite the implement coupler assembly being removed from the implement carrier. This allows the same implement carrier to be used on all similarly sized machines.

Hydraulic coupling

A hydraulic assembly for an extendable lift arm assembly can include an extension cylinder, a leveling cylinder, a main control valve, a flow combiner/divider, and one or more flow-blocking arrangements. The main control valve can be configured to control commanded movement of the extension and leveling cylinders of the lift arm assembly. The flow combiner/divider can be configured to hydraulically link the extension cylinder with the leveling cylinder for synchronized operation of the extension cylinder and the leveling cylinder. The one or more flow-blocking arrangements can be configured to restrict flow from rod or base ends of the leveling or extension cylinders during commanded extension or retraction of the leveling and extension cylinders, or in the absence of commanded movement of the leveling and extension cylinders, to maintain synchronized orientation of the leveling and extension cylinders.

Hydraulic leveling circuit for power machines

A lift arm structure for a power machine with a frame can include a multi-bar linkage that is pivotally secured to the frame and a leveling link that is pivotally secured to the multi-bar linkage. The leveling link can be configured to transmit force from the leveling link to an implement as the multi-bar linkage is actuated to raise or lower the implement, including via a multi joint member that is pivotally secured to the leveling link, the multi-bar linkage, and an actuator that is configured to move the implement.

Mechanical self-leveling lift arm structure for power machine

Disclosed embodiments include power machines, such as front-end loaders and utility vehicles, with a lift arm and a bucket leveling system utilizing four-bar linkages which mechanically level an attached implement as the lift arm is raised and lowered.

Lift arm leveling system

The present disclosure includes independent suspension systems or members, as well as wheeled skid steer loaders or other power machines including the same, that couple each wheel to a machine frame using a four-bar linkage, with the four bars including the frame of the machine, an upper control arm, a lower control arm, and a wheel carrier link. Each control arm is pivotally attached to both the machine frame and one end of the wheel carrier link. The four pivots between the control arms and the wheel carrier link are configured to all be contained within cylinder defined by the outer diameter of the wheel rim, allowing for a compact structure with the wheel carrier link and at least part of the control arms being positioned within this volume when the loader is in a resting position.

Loader suspension

A drive system for propelling a power machine over a support surface is disclosed. The drive system includes a hydraulic pressure source and a drive assembly. The drive assembly has a hydraulic motor in fluid communication with the hydraulic pressure source that is switchable between first and second displacement arrangements. A shift valve receives pressurized fluid from the hydraulic pressure source and provides a shift signal to the hydraulic motor to selectively cause the displacement of the hydraulic motor to shift between the first and second displacement arrangements. A sensing device capable of generating a load signal indicative of a load condition provided by the drive assembly is also provided. An electronic controller provides a control signal to the shift valve to control the displacement of the hydraulic motor in response at least in part due to the load signal.

Automated shifting of hydraulic drive systems

A fluid pressure cylinder assembly has a sensor to provide a signal indicating the amount of extension of a piston rod from the cylinder. The sensor includes a sleeve that is fixed relative to a base of the cylinder and passes into a longitudinal bore in the piston rod, and the piston rod carries a sensor core that is in the bore and is secured to the piston rod at an end opposite from a piston on the rod. The core slides on the interior of the sensor sleeve. A connection is provided to the sensor sleeve such that as the core moves relative to the sensor sleeve a signal indicating the amount of movement and the relative position of the cylinder base and the piston rod is provided.

Hydraulic cylinder rod position sensor

A hydraulic system includes first and second pumps, first and second motors, and three valves for selectively creating combined and basic hydraulic flow. The arrangement of valves permits combined flow to be provided to both motors in series to cause high speed operation of the motors, and permits combined flow to be provided to one motor and basic flow to the other motor. When applied to a vehicle, the arrangement provides a steerable high speed series arrangement of the vehicle's drive motors.

Steerable series two speed motor configuration

A piston is disclosed that includes a longitudinal passage disposed between outlets on the opposing faces of the piston, and a radial passage extending from a node with the longitudinal passage to an outlet on the annular wall between opposing piston seals. Check valves are disposed in the longitudinal passage between the node and each of the piston faces, such that each of the check valves enables fluid flow from its inlet to the outlet on the annular wall, and block fluid flow from the outlet on the annular wall to the inlet. In the event of pistons in a fluid system becoming out of phase with each other, fluid may be admitted through the inlet of the longitudinal passage and the respective check valve and out a side wall outlet, thereby bypassing the piston to exit via the respective end port, until another, out-of-phase piston or pistons in the system also reach full extension or retraction, automatically returning all pistons in the system to be in phase with each other.

Passively rephasing piston

A hydraulic system comprising: a first pump, in fluid communication with a first valve; a second pump, in fluid communication with a second valve; an auxiliary passage, in fluid communication with the first valve and the second valve; and a supplemental apparatus, in fluid communication via a supplemental passage with the second valve and the auxiliary passage, wherein the supplemental apparatus comprises a relief valve.

Growing community of inventors

Bismarck, ND, United States of America

Daniel J Krieger