A method for controlling a hydraulic control system that includes a variable pressure relief valve and may include steps for calibrating the hydraulic control system. The hydraulic control system may be calibrated by: controlling, with the controller, the variable pressure relief valve to move to a fully open position, increasing, with the pump, a fluid pressure upstream of the variable pressure relief valve, controlling, with the controller, the variable pressure relief valve to move from the fully open position toward a fully closed position by adjusting a control signal supplied to the variable pressure relief valve, monitoring, with the controller, the pressure detected by the pressure sensor, and recording, with the controller, a parameter of the control signal supplied to the variable pressure relief valve when the pressure detected by the pressure sensor reaches a target pressure.

A method for controlling a hydraulic control system that includes a variable pressure relief valve and may include steps for calibrating the hydraulic control system. The hydraulic control system may be calibrated by: controlling, with the controller, the variable pressure relief valve to move to a fully open position, increasing, with the pump, a fluid pressure upstream of the variable pressure relief valve, controlling, with the controller, the variable pressure relief valve to move from the fully open position toward a fully closed position by adjusting a control signal supplied to the variable pressure relief valve, monitoring, with the controller, the pressure detected by the pressure sensor, and recording, with the controller, a parameter of the control signal supplied to the variable pressure relief valve when the pressure detected by the pressure sensor reaches a target pressure.

An operating method for an industrial truck. The industrial truck includes a hydraulic pump which provides a hydraulic output, an output setpoint value generator which controls the hydraulic output to influence a traveling speed, two drive wheels which respectively comprise a hydraulic drive unit driven via the hydraulic pump, and a hydraulic device. The hydraulic device is switchable between a first switching state, where the hydraulic drive units are supplied with hydraulic outputs which are different, and a second switching state, where the hydraulic drive units are supplied with hydraulic outputs that have a particular ratio with respect to each other. The operating method includes detecting at least one operating parameter of the output setpoint value generator, comparing the at least one operating parameter with a predefined threshold value, and moving the hydraulic device from the first switching state to the second switching state based on the comparison.

An operating method for an industrial truck. The industrial truck includes a hydraulic pump which provides a hydraulic output, an output setpoint value generator which controls the hydraulic output to influence a traveling speed, two drive wheels which respectively comprise a hydraulic drive unit driven via the hydraulic pump, and a hydraulic device. The hydraulic device is switchable between a first switching state, where the hydraulic drive units are supplied with hydraulic outputs which are different, and a second switching state, where the hydraulic drive units are supplied with hydraulic outputs that have a particular ratio with respect to each other. The operating method includes detecting at least one operating parameter of the output setpoint value generator, comparing the at least one operating parameter with a predefined threshold value, and moving the hydraulic device from the first switching state to the second switching state based on the comparison.

The present disclosure is a lift attachment apparatus for construction and farm equipment, including a loader. In an embodiment of the disclosure, lift apparatus may include a frame including an attachment device configured to attach to a tilting plane of a loader having a forward facing loader arm, a pair of wheels connected to the frame, a first wheel of the pair of wheels located on a first side of the frame and a second wheel of the pair of wheels located on a second side of the frame. The lift attachment apparatus may further include a boom or forks connected directly or indirectly to the frame, wherein control of the boom or forks is provided by application of force to the attachment device by the forward facing loader arm in a downward direction to create lift and rotation of the tilting plane causing rotation of an end of the boom or forks about the first wheel and the second wheel. The first wheel and second wheel being mechanically aligned to act as a stable fulcrum.

The present disclosure is a lift attachment apparatus for construction and farm equipment, including a loader. In an embodiment of the disclosure, lift apparatus may include a frame including an attachment device configured to attach to a tilting plane of a loader having a forward facing loader arm, a pair of wheels connected to the frame, a first wheel of the pair of wheels located on a first side of the frame and a second wheel of the pair of wheels located on a second side of the frame. The lift attachment apparatus may further include a boom or forks connected directly or indirectly to the frame, wherein control of the boom or forks is provided by application of force to the attachment device by the forward facing loader arm in a downward direction to create lift and rotation of the tilting plane causing rotation of an end of the boom or forks about the first wheel and the second wheel. The first wheel and second wheel being mechanically aligned to act as a stable fulcrum.

The present invention discloses a liquid-cooled integrative power system for electric forklift and a control method thereof. It includes an integrated transmission gearbox, an integrated motor controller, an oil pump and a vehicle controller. The integrated transmission gearbox includes a drive motor transmission mechanism and an oil pump motor transmission mechanism. The integrated motor controller includes a control unit for a drive motor and a control unit for an oil pump motor. The integrated transmission gearbox, the integrated motor controller, the drive motor, the oil pump motor, the oil pump and the vehicle controller are completely integrated and mounted to form the liquid-cooled integrative power system for electric forklift. The vehicle controller comprehensively controls the integrative power system.

The present invention discloses a liquid-cooled integrative power system for electric forklift and a control method thereof. It includes an integrated transmission gearbox, an integrated motor controller, an oil pump and a vehicle controller. The integrated transmission gearbox includes a drive motor transmission mechanism and an oil pump motor transmission mechanism. The integrated motor controller includes a control unit for a drive motor and a control unit for an oil pump motor. The integrated transmission gearbox, the integrated motor controller, the drive motor, the oil pump motor, the oil pump and the vehicle controller are completely integrated and mounted to form the liquid-cooled integrative power system for electric forklift. The vehicle controller comprehensively controls the integrative power system.

A pallet truck includes a drive frame on which a drive wheel support is pivotably supported, a load frame, which is liftable with respect to the drive frame in a lifting direction, and a hydraulic lift module, which interconnects the drive frame and the load frame. The hydraulic lift module includes a hydraulic lift cylinder, which includes a cylinder barrel and a piston rod, wherein the cylinder barrel includes a cap end at one end portion of the cylinder barrel and a rod end at the other end portion of the cylinder barrel, wherein the piston rod extends outwards from the cylinder barrel at the rod end of the cylinder barrel and wherein a free end of the piston rod is accommodated in the drive frame. In the lifting direction, the cap end of the cylinder barrel is arranged above the rod end of the cylinder barrel.

A pallet truck includes a drive frame on which a drive wheel support is pivotably supported, a load frame, which is liftable with respect to the drive frame in a lifting direction, and a hydraulic lift module, which interconnects the drive frame and the load frame. The hydraulic lift module includes a hydraulic lift cylinder, which includes a cylinder barrel and a piston rod, wherein the cylinder barrel includes a cap end at one end portion of the cylinder barrel and a rod end at the other end portion of the cylinder barrel, wherein the piston rod extends outwards from the cylinder barrel at the rod end of the cylinder barrel and wherein a free end of the piston rod is accommodated in the drive frame. In the lifting direction, the cap end of the cylinder barrel is arranged above the rod end of the cylinder barrel.