Abstract: A steering system and method is described for a vehicle having steerable front and rear wheels, and a steering input device for receiving manual steering input. Front and rear hydraulic steering devices may be coupled, respectively, to the front and rear wheels. Front and rear valve assemblies may be configured, respectively, to steer the front and rear wheels. In a manual steering mode, the front valve assembly may be disabled with respect to the front steering device, and the front hydraulic steering device may steer the front wheels based upon the manual steering input. In a rear steering assist mode, a rear steering command may be determined based upon the manual steering input, and the rear wheels steered based upon the rear steering command. In an automated steering mode, the front and rear wheels may be automatically steered based upon a target path of travel for the vehicle.

Abstract: A steering system is described for a vehicle having steerable wheels. A hydraulic charge pressure circuit may be configured to provide charge pressure to one or more hydraulic components of the vehicle, and a hydraulic drive pressure circuit may be configured to provide working pressure to one or more other hydraulic components of the vehicle. Hydraulic machines may rotate front wheels in order to drive the vehicle, and a front valve assembly may control steering of the front wheels by controlling the hydraulic machines. The hydraulic machines may be driven to rotate the front wheels by the working pressure from the hydraulic drive pressure circuit, and the front valve assembly may control the front hydraulic machines to steer the agricultural vehicle by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly.

Abstract: A steering system and method are described for a vehicle having steerable front and rear wheels. A rear hydraulic steering device may be coupled to one or more of the rear wheels. A rear valve assembly may hydraulically control the rear hydraulic steering device to steer the rear wheels based upon a rear steering command. In a rear steering assist mode, the rear steering command may be determined based upon a manual steering input received at a steering input device. In an automated steering mode, the rear steering command may be determined based upon a target path of the agricultural vehicle that is determined independently of the manual steering input.

Abstract: A steering system is described for a vehicle having steerable wheels. A hydraulic charge pressure circuit may be configured to provide charge pressure to one or more hydraulic components of the vehicle, and a hydraulic drive pressure circuit may be configured to provide working pressure to one or more other hydraulic components of the vehicle. Hydraulic machines may rotate front wheels in order to drive the vehicle, and a front valve assembly may control steering of the front wheels by controlling the hydraulic machines. The hydraulic machines may be driven to rotate the front wheels by the working pressure from the hydraulic drive pressure circuit, and the front valve assembly may control the front hydraulic machines to steer the agricultural vehicle by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly.

Abstract: A steering system and method are described for a vehicle having steerable front and rear wheels. A rear hydraulic steering device may be coupled to one or more of the rear wheels. A rear valve assembly may hydraulically control the rear hydraulic steering device to steer the rear wheels based upon a rear steering command. In a rear steering assist mode, the rear steering command may be determined based upon a manual steering input received at a steering input device. In an automated steering mode, the rear steering command may be determined based upon a target path of the agricultural vehicle that is determined independently of the manual steering input.

Abstract: A pressure control system is described for a vehicle having a hydraulically actuated header. The system may include a hydraulic lifting circuit for raising and lowering the header, a hydraulic float circuit for floating the header, and a drain tank. A lifting circuit control valve may be configured to control drainage of hydraulic fluid from the hydraulic lifting circuit to the drain tank. A float circuit control valve may be configured to control drainage of hydraulic fluid from the hydraulic float circuit to the drain tank. A user interface may be configured to receive one or more inputs to control drainage of hydraulic fluid from the hydraulic circuits. Based upon the one or more inputs, at least one of the control valves may be opened, in order to depressurize, respectively, one of the hydraulic circuits.

Abstract: A steering system and method is described for a vehicle having steerable front and rear wheels, and a steering input device for receiving manual steering input. Front and rear hydraulic steering devices may be coupled, respectively, to the front and rear wheels. Front and rear valve assemblies may be configured, respectively, to steer the front and rear wheels. In a manual steering mode, the front valve assembly may be disabled with respect to the front steering device, and the front hydraulic steering device may steer the front wheels based upon the manual steering input. In a rear steering assist mode, a rear steering command may be determined based upon the manual steering input, and the rear wheels steered based upon the rear steering command. In an automated steering mode, the front and rear wheels may be automatically steered based upon a target path of travel for the vehicle.

Abstract: A steering system and method are described for a vehicle having steerable wheels, with steering of the wheels controlled, at least in part, by a valve assembly. A ground speed of the vehicle may be determined. Whether a steering command is being provided to a valve assembly may also be determined. An operational pressure at the valve assembly may be determined with a pressure sensor. A threshold pressure may be determined based upon the ground speed and/or whether a steering command is currently being provided. The operational pressure may then be compared with the operational pressure, and steering control with the valve assembly disabled based upon the comparison.

Abstract: A four-bar linkage is provided as a mechanical interface for transferring respective outputs from a speed/direction control device and a hydraulic steering cylinder to displacement control arms of a pair of pumps of a dual-path hydrostatic transmission including a pair of motors respectively coupled for driving a pair of front wheels of a vehicle. The hydraulic steering cylinder is fixed and has a piston rod slidably coupled to an input arm of the four-bar linkage in such a way that a rotation speed decrease occurs as the arm and a linked control plate are pivoted from a neutral position, the control plate transferring pivotal movement to effect differential movement of the displacement control arms. This results in the vehicle speed decreasing during a turn.

Abstract: A control arm assembly connected with a hydraulic pump allows for the adjustment of pump displacement by turning a threaded adjustment rod clockwise or counter-clockwise to move a half nut connected with a control rod vertically up or down in a slot of an arm to the desired set point. The half nut has a partial thread that engages the thread of the adjustment rod to control the vertical movement. The design allows for the positive repeatable finite adjustment of the half nut with minimal backlash that reduces the difficulty of the setting process in labor and assembly time. Once the desired set point has been met the adjustment rod is clamped tight to the second arm by tightening the nut against the notch to lock up the assembly to prevent any movement.

Abstract: A four-bar linkage is provided as a mechanical interface for transferring respective outputs from a speed/direction control device and a hydraulic steering cylinder to displacement control arms of a pair of pumps of a dual-path hydrostatic transmission including a pair of motors respectively coupled for driving a pair of front wheels of a vehicle. The hydraulic steering cylinder is fixed and has a piston rod slidably coupled to an input arm of the four-bar linkage in such a way that a rotation speed decrease occurs as the arm and a linked control plate are pivoted from a neutral position, the control plate transferring pivotal movement to effect differential movement of the displacement control arms. This results in the vehicle speed decreasing during a turn.

Abstract: Adjustable control arms for dual path hydrostatic pumps have first and second arms interconnected by an eccentric mechanism with a common pivot point on a pivotal control input shaft for the pumps. The control arms are adjusted at a minimal pump output such as 500 r.p.m. by varying the eccentric to achieve equal r.p.m. The throw of the pump arms is adjusted at a maximum pump output r.p.m., such as approximately 4000 r.p.m., to achieve uniform tracking, steering, and directional control from the dual path hydrostatic pumps.

Abstract: A plurality of twine tensioner arms are mounted at evenly spaced locations across the baling chamber of a large square baler for pivoting vertically, against a yieldable bias, between upper and lower extreme positions. Each tensioner arm carries a tensioned twine strand associated with a double-knot tying device. A rotary potentiometer is coupled, by a follower arm, for sensing pivotal movement of each tensioner arm and sends out a corresponding electrical signal to an electronic controller which processes the sensed arm position together with other stored information and sends out a signal for energizing a display showing the relative positions of the arms and/or for energizing a warning device for apprising an operator that a mistie has occurred, is about to occur or that a twine tensioner setting has to be changed.

Abstract: A control arm assembly connected with a hydraulic pump allows for the adjustment of pump displacement by turning a threaded adjustment rod clockwise or counter-clockwise to move a half nut connected with a control rod vertically up or down in a slot of an arm to the desired set point. The half nut has a partial thread that engages the thread of the adjustment rod to control the vertical movement. The design allows for the positive repeatable finite adjustment of the half nut with minimal backlash that reduces the difficulty of the setting process in labor and assembly time. Once the desired set point has been met the adjustment rod is clamped tight to the second arm by tightening the nut against the notch to lock up the assembly to prevent any movement.

Abstract: A steering arrangement for a work machine includes a frame, at least one caster wheel assembly carried by the frame, at least one turn assist cylinder, and a turn assist arrangement. Each turn assist cylinder is coupled between the frame and a corresponding caster wheel assembly. The turn assist arrangement includes a steering assembly, a steering assist valve and a transfer gear. The steering assembly includes an output gear which is positionable dependent upon an operator commanded degree of turn. The output gear has exterior teeth. The steering assist valve is configured to selectively operate at least one turn assist cylinder and thereby bias a corresponding caster wheel assembly during an operator commanded turn. The steering assist valve includes an input gear with exterior teeth. The transfer gear includes a first set of peripheral teeth enmeshed with the output gear and a second set of peripheral teeth enmeshed with the input gear. The transfer gear pivots about a common pivot point.

Abstract: A steering arrangement for a work machine includes a frame, at least one caster wheel assembly carried by the frame, at least one turn assist cylinder, and a turn assist arrangement. Each turn assist cylinder is coupled between the frame and a corresponding caster wheel assembly. The turn assist arrangement includes a steering assembly, a steering assist valve and a transfer gear. The steering assembly includes an output gear which is positionable dependent upon an operator commanded degree of turn. The output gear has exterior teeth. The steering assist valve is configured to selectively operate at least one turn assist cylinder and thereby bias a corresponding caster wheel assembly during an operator commanded turn. The steering assist valve includes an input gear with exterior teeth. The transfer gear includes a first set of peripheral teeth enmeshed with the output gear and a second set of peripheral teeth enmeshed with the input gear. The transfer gear pivots about a common pivot point.

Abstract: Adjustable control arms for dual path hydrostatic pumps have first and second arms interconnected by an eccentric mechanism with a common pivot point on a pivotal control input shaft for the pumps. The control arms are adjusted at a minimal pump output such as 500 r.p.m. by varying the eccentric to achieve equal r.p.m. The throw of the pump arms is adjusted at a maximum pump output r.p.m., such as approximately 4000 r.p.m., to achieve uniform tracking, steering, and directional control from the dual path hydrostatic pumps.