A drive train (1) includes an internal combustion engine (2) and working hydraulics (4) having at least one hydraulic pump (7). When operated as a pump, the hydraulic pump (7) sucks hydraulic fluid from a tank (9) and delivers into a delivery line (10) that leads to the working hydraulics (4). When operated as a motor, the hydraulic pump (7) is supplied with hydraulic fluid from a hydraulic accumulator (25). The drive train (1) has a charge pump (20) to supply a charging circuit (23). The charge pump (20), when operated as a pump, sucks hydraulic fluid out of the tank (9) and delivers into a charge pressure line (22) that leads to a charging circuit (23), and the charge pump (20) when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator (25).

A drive train (1) includes an internal combustion engine (2) and working hydraulics (4) having at least one hydraulic pump (7). When operated as a pump, the hydraulic pump (7) sucks hydraulic fluid from a tank (9) and delivers into a delivery line (10) that leads to the working hydraulics (4). When operated as a motor, the hydraulic pump (7) is supplied with hydraulic fluid from a hydraulic accumulator (25). The drive train (1) has a charge pump (20) to supply a charging circuit (23). The charge pump (20), when operated as a pump, sucks hydraulic fluid out of the tank (9) and delivers into a charge pressure line (22) that leads to a charging circuit (23), and the charge pump (20) when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator (25).

Industrial truck with a drive part and a load part with two wheel arms that is height-adjustable relative to the drive part, wherein each of the wheel arms has a wheel arm lever, which has at least one load roller and is pivotably articulated on the wheel arm, and a rod, via which a height adjusting movement of the load part is coupled with a pivoting movement of the wheel arm lever, wherein the rod has a hydraulic cylinder, with which a length of the rod is adjustable and which has an operating volume, characterized in that the two rods are push rods, and the industrial truck has a pressure accumulator, which is connectable with the operating volumes of the two hydraulic cylinders.

Industrial truck with a drive part and a load part with two wheel arms that is height-adjustable relative to the drive part, wherein each of the wheel arms has a wheel arm lever, which has at least one load roller and is pivotably articulated on the wheel arm, and a rod, via which a height adjusting movement of the load part is coupled with a pivoting movement of the wheel arm lever, wherein the rod has a hydraulic cylinder, with which a length of the rod is adjustable and which has an operating volume, characterized in that the two rods are push rods, and the industrial truck has a pressure accumulator, which is connectable with the operating volumes of the two hydraulic cylinders.

The invention relates to an industrial truck (2) with a lift mast (4), a hydraulic system (10) as well as a method for operating a hydraulic system (10). The lift mast (4) of the industrial truck (2) is driven by a mast lift cylinder (12) and comprises at least one mast lift stage (42, 42). Furthermore, a free lift stage is present that is driven by a free lift cylinder (8) with which a load receiving means (6) can be displaced along the lift mast (4). The industrial truck (2) comprises a hydraulic system (10) for supplying the at least one mast lift cylinder (12) and the at least one free lift cylinder (8) with a hydraulic fluid (14), wherein the hydraulic system (10) is configured to at least at times simultaneously actuate the at least one mast lift cylinder (12) and the at least one free lift cylinder (8) in load lifting operation and/or in load lowering operation.

The invention relates to an industrial truck (2) with a lift mast (4), a hydraulic system (10) as well as a method for operating a hydraulic system (10). The lift mast (4) of the industrial truck (2) is driven by a mast lift cylinder (12) and comprises at least one mast lift stage (42, 42). Furthermore, a free lift stage is present that is driven by a free lift cylinder (8) with which a load receiving means (6) can be displaced along the lift mast (4). The industrial truck (2) comprises a hydraulic system (10) for supplying the at least one mast lift cylinder (12) and the at least one free lift cylinder (8) with a hydraulic fluid (14), wherein the hydraulic system (10) is configured to at least at times simultaneously actuate the at least one mast lift cylinder (12) and the at least one free lift cylinder (8) in load lifting operation and/or in load lowering operation.

Lift trucks designed with a common chassis can include an ergonomically improved operator compartment, wheels, lift assembly, power plant, energy source, steering, seat, and counterweight components. Modular chassis designs can accommodate different form factors and different energy sources to accommodate different end uses of the lift truck, including lift trucks having a low floor, seatside steering, and/or a combination of operator-inaccessible compartments for high-reliability components and operator-accessible components for components that may require more frequent or convenient access. In one embodiment, the energy source is a lithium-ion battery bank in an operator-inaccessible compartment under a low, broad floor that facilitates easy entry into and exit from the operator compartment as well as ergonomic operation by the operator.

Lift trucks designed with a common chassis can include an ergonomically improved operator compartment, wheels, lift assembly, power plant, energy source, steering, seat, and counterweight components. Modular chassis designs can accommodate different form factors and different energy sources to accommodate different end uses of the lift truck, including lift trucks having a low floor, seatside steering, and/or a combination of operator-inaccessible compartments for high-reliability components and operator-accessible components for components that may require more frequent or convenient access. In one embodiment, the energy source is a lithium-ion battery bank in an operator-inaccessible compartment under a low, broad floor that facilitates easy entry into and exit from the operator compartment as well as ergonomic operation by the operator.

An apparatus for controlling a load handling device of an industrial vehicle includes a lifted height detector that detects a lifted height of the load handling device, a tilt angle detector that detects a tilt angle of the load handling device, a loading pump that pumps hydraulic oil from a hydraulic tank in the industrial vehicle and supplies the hydraulic oil to a lift cylinder and a tilt cylinder, a drive that drives the loading pump, and a controller that controls the flow rate of hydraulic oil supplied to the lift cylinder and the tilt cylinder. When the forward tilt angle of the load handling device is greater than a first regulation tilt angle and a lifted height of the load handling device is higher than a predetermined reference height, the controller regulates the flow rate of hydraulic oil supplied to the lift cylinder.

An apparatus for controlling a load handling device of an industrial vehicle includes a lifted height detector that detects a lifted height of the load handling device, a tilt angle detector that detects a tilt angle of the load handling device, a loading pump that pumps hydraulic oil from a hydraulic tank in the industrial vehicle and supplies the hydraulic oil to a lift cylinder and a tilt cylinder, a drive that drives the loading pump, and a controller that controls the flow rate of hydraulic oil supplied to the lift cylinder and the tilt cylinder. When the forward tilt angle of the load handling device is greater than a first regulation tilt angle and a lifted height of the load handling device is higher than a predetermined reference height, the controller regulates the flow rate of hydraulic oil supplied to the lift cylinder.