A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.

A hydraulic rear axle steering for multi-axle vehicles, including a steering cylinder with a piston and two working chambers. The steering cylinder has a mechanical blocking device, which blocks the piston when it reaches a central position within the steering cylinder. The blocking device has a blocking member, which is retained in an engaged position by a locking element in the blocked state. The locking element is movable by a separate, hydraulically actuated actuator between a blocking position and a first unblocking position in which the locking element releases the blocking element. An admission-pressure-controlled load safety valve is provided for each working chamber, and control connections of the valves are connected to a pressure line leading to the respective other working chamber. The actuator is adjusted such that, when a lower, first pressure value is applied, the locking element moves into the unblocking position, and the valves are adjusted such that, when a higher, second pressure value is applied, the valves open towards the tank.

A self-setting valve assembly for a power steering gear assembly includes a plug, a first plunger, a second plunger, and a biasing member. The plug extends between a first end and a second end. The plug defines a cavity that is disposed between the first end and the second end, a first bore that extends from the first end to the cavity, and a second bore that extends from the second end to the cavity. The first plunger has a first head that is disposed within the cavity and a first stem that extends from the first head through the first bore. The second plunger has a second head that is disposed within the cavity and a second stem that extends from the first head through the second bore. The biasing member is disposed within the bore and extending between the first head and the second head.

A pilot neutralizing system of a work vehicle may include a pilot neutralizer. The work vehicle may include a first frame portion and a second frame portion. The work vehicle has an actuating assembly used to pivot the first frame portion relative to the second frame portion. The pilot neutralizer is electrically coupled to a controller receiving a signal indicative of an articulation position. The pilot neutralizer is hydraulically coupled between an operator control member and a steering valve to selectively change a pilot signal at the steering valve. The pilot signal is used to switch the steering valve to change a direction of a hydraulic fluid flowing from the steering valve to the actuating assembly. When the articulation position reaches a cushion region during steering, the pilot neutralizer is de-energized or energized by the controller to change the pilot signal at the steering valve to resist the actuating assembly from moving.

A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.

In a power steering system employing an end of travel system including valve actuating rings disposed about a Pitman arm shaft, a device is provided for setting the positions of the rings on the shaft. The device includes a fixed member positioned about, and fixed against movement along, a longitudinal axis perpendicular to the shaft's rotational axis and a movable member that moves along the longitudinal axis relative to the fixed member. The movable member defines a pin at one end configured for engagement with the circumferential ends of the actuating rings. A positioning force applied to one of the members causes the movable member to move between set and reset positions in which the pin engages corresponding ends of the actuating rings during rotation of the shaft and a running position in which the pin remains disengaged from the ends of the actuating ring during rotation of the shaft.

A hydraulic steering unit includes a pressure port connected to a main flow path and a tank port connected to a tank flow path, left and right working ports connected to left and right working flow paths, respectively, a bridge arrangement of variable orifices having a first left orifice connected to the main flow path and to the left working flow path, a first right orifice connected to the main flow path and to the right working flow path, a second left orifice connected to the left working flow path and to the tank flow path, and a second right orifice connected to the right working flow path and to the tank flow path. A variable diagonal orifice is connected to the main flow path and to the tank flow path. The bridge arrangement orifices being closed in neutral position and the diagonal orifice being open in neutral position.

A plunger assembly for a power steering system comprises a plunger and a tappet. The plunger is disposed within and longitudinally movable along a plunger passageway in a housing of the power steering system. The tappet is disposed within and longitudinally movable along a port defined by the housing. The port is disposed at an angle with respect to the plunger passageway within the housing. The port communicates with the plunger passageway and an area exterior of the power steering system. A power steering system and method of setting the same are also disclosed.

An improved power steering assembly is provided. The power steering assembly includes an end-of-travel mechanism and a valve cartridge that is actuated by left and right actuator rings of the end-of-travel mechanism, the actuator rings extending partially around an output shaft. The actuator rings can be individually set for the desired end-of-travel relief to limit the maximum system pressure when the steering assembly approaches the desired axle stop setting. The valve cartridge provides an end-of-travel function and a pressure relief function and is in fluid communication with the left and right pressure chambers to recirculate hydraulic fluid in the event of a power off condition.

The invention relates to a mobile crane travel gear axle with suspensions, which are independent of one another, of the wheel carriers arranged on both sides of the travel gear frame of the mobile crane, wherein the suspensions each have at least one transverse link which couples the wheel carrier to the travel gear frame and which is connected to the travel gear frame so as to be rotatable about an axis extending substantially parallel to the longitudinal axis of the travel gear frame.