A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

When a fluid control valve is opened and closed, the port pressure of fluid control valve is guided to a main relief valve through a first passage, and its maximum pressure is controlled by the main relief valve. At the same time, the port pressure of fluid control valve is guided to pressure compensation valves of the respective fluid control valves. As a result, even when functions having different load pressures are simultaneously operated in the fluid control valves, constant operability can be always secured without depending on the load pressures. In addition, when the fluid control valve, which drives a tilt cylinder for a function of tilting a fork, is opened and closed, the port pressure of the fluid control valve is guided to a secondary relief valve through a second passage, and is also guided to the main relief valve and the pressure compensation valves of the respective fluid control valves through the first passage.

When a fluid control valve is opened and closed, the port pressure of fluid control valve is guided to a main relief valve through a first passage, and its maximum pressure is controlled by the main relief valve. At the same time, the port pressure of fluid control valve is guided to pressure compensation valves of the respective fluid control valves. As a result, even when functions having different load pressures are simultaneously operated in the fluid control valves, constant operability can be always secured without depending on the load pressures. In addition, when the fluid control valve, which drives a tilt cylinder for a function of tilting a fork, is opened and closed, the port pressure of the fluid control valve is guided to a secondary relief valve through a second passage, and is also guided to the main relief valve and the pressure compensation valves of the respective fluid control valves through the first passage.

A vehicle includes a chassis, an implement coupled to the chassis, a hydraulic actuator configured to move the implement relative to the chassis, a tractive element coupled to the chassis, a hydraulic motor configured to drive the tractive element to propel the vehicle, a drive pump fluidly coupled to the hydraulic motor, a charge pump coupled to the chassis and configured to provide a flow of pressurized fluid, and a valve assembly fluidly coupled to the charge pump. The valve assembly is configured to (a) direct a first portion of the flow of pressurized fluid to the drive pump and (b) selectively direct a second portion of the flow of pressurized fluid to the hydraulic actuator.

A vehicle includes a chassis, an implement coupled to the chassis, a hydraulic actuator configured to move the implement relative to the chassis, a tractive element coupled to the chassis, a hydraulic motor configured to drive the tractive element to propel the vehicle, a drive pump fluidly coupled to the hydraulic motor, a charge pump coupled to the chassis and configured to provide a flow of pressurized fluid, and a valve assembly fluidly coupled to the charge pump. The valve assembly is configured to (a) direct a first portion of the flow of pressurized fluid to the drive pump and (b) selectively direct a second portion of the flow of pressurized fluid to the hydraulic actuator.

A center of gravity estimation device includes a tilt cylinder pressure sensor detecting a pressure on a rod side of the tilt cylinder, a tilt cylinder pressure sensor detecting a pressure on a bottom side of the tilt cylinder, a lift cylinder pressure sensor detecting a pressure of a lift cylinder, and an electronic control unit performing estimation calculation of a center of gravity of a cargo W loaded on a fork using the pressure on the rod side of the tilt cylinder, the pressure on the bottom side of the tilt cylinder, the pressure of the lift cylinder, and data on a structure of a cargo handling device.

A load wheel assembly for an elongate fork of a forked material-handling vehicle with a chassis employs a non-motorized forward load wheel, a non-motorized rear load wheel, and a non-motorized torque-coupling assembly connected between the forward load wheel and the rear load wheel for coupling torque between the forward load wheel and the rear load wheel to overcome obstacles on a surface, such as a floor.

A load wheel assembly for an elongate fork of a forked material-handling vehicle with a chassis employs a non-motorized forward load wheel, a non-motorized rear load wheel, and a non-motorized torque-coupling assembly connected between the forward load wheel and the rear load wheel for coupling torque between the forward load wheel and the rear load wheel to overcome obstacles on a surface, such as a floor.

A hydraulic system can include a hydraulic actuator including a piston rod slidably disposed within a housing having a base-side port and a rod-side port, a hydraulic pump, a hydraulic reservoir, an accumulator, a first control valve operable to selectively control flow from the pump to the base-side port and from the base-side port to the reservoir, a second control valve operable to selectively control flow from the pump to the rod-side port and from the rod-side port to the reservoir, a third control valve operable to selectively allow flow between the base-side port and the accumulator, and a controller for operating the hydraulic system and including a ride control mode in which damping is provided to the hydraulic actuator by operation of the first, second, and third control valves.