A hydraulic drive including at least one hydraulic cylinder that includes a piston chamber, an annulus, and a piston that separates the piston chamber from the annulus. The hydraulic drive also includes a first hydraulic pump hydraulically connected with the piston chamber, a second hydraulic pump hydraulically connected with the annulus, a third hydraulic pump, and a directional control valve that has a first switching position and a second switching position. The third hydraulic pump in the first switching position of the directional control valve is hydraulically connected with the piston chamber, and the third hydraulic pump in the second switching position of the directional control valve is not hydraulically connected with the piston chamber.

A baler includes a chamber having a fixed size that receives crops and houses a formed bale. A tailgate is connected to a frame and is movable between a closed position, for cooperating with the frame to delimit the chamber, and an open position, for discharging the formed bale. A conveying assembly delimits the chamber for imparting a rotating movement to the crops contained in the chamber, and has a first portion provided in the frame and a second portion provided in the tailgate. An actuator includes a closing chamber and moves the tailgate from the open position to the closed position upon receiving an actuating fluid in the closing chamber. A binder binds the formed bale, and a pressure sensor detects a control signal representative of a pressure inside the closing chamber of the actuator. A control unit generates an alert signal as a function of the control signal.

A hydraulic drive system for an electrically-driven hydraulic work machine makes it possible to make a rated voltage of various electric equipment such as power storage devices common to one of an electrically-driven hydraulic work machine that is capable of being operated with lower horsepower and to prevent that only a power storage situation of one of the plurality of power storage devices significantly degrades together with operation of the electrically-driven hydraulic work machine and besides, to extend a time period within which each of actuators of the electrically-driven hydraulic work machine can obtain a predetermined speed. Accordingly, a controller 50 includes a virtual limitation torque calculation section 51 and electric motor rotational speed control sections 52 and 53. Variable horsepower control tables 52r and 53r are provided in the electric motor rotational speed control sections 52 and 53, and limit values q1*limit and q2*limit for a virtual displacement of the variable horsepower control tables 52r and 53r are changed such that a charge state of a power storage device 170 and a charge state of another power storage device 270 become equal to each other.

A method of controlling hydraulic fluid flow to an implement of a material handling vehicle includes coupling a boom arm to a vehicle frame for rotation about the vehicle frame, rotating a boom arm with respect to the vehicle frame with an actuator, coupling an attachment to the boom arm for rotation with respect to the boom arm, sensing a pressure of fluid in the actuator, communicating the sensed pressure to a control system, determining a baseline pressure of the attachment based upon the sensed pressure of the fluid in the actuator, and limiting fluid flow to the actuator with a control valve in response to the sensed pressure of the fluid in the actuator being above the baseline pressure.

A hydraulic system includes a supply line, at least one implement-based control valve, an implement-based pressure regulating valve, and a load sensing circuit. The implement-based control valve(s) is fluidly coupled to the supply line and configured to regulate a flow of the pressurized hydraulic fluid supplied through at least one downstream actuator line to at least one hydraulic actuator of the implement. The implement-based pressure regulating valve is fluidly coupled to the supply line upstream of the control valve(s) and configured to regulate a fluid pressure to be equal to or greater than a minimum fluid pressure. The load sensing circuit is fluidly coupled to the pressure regulating valve and provides a line or load pressure to the pressure regulating valve. The pressure regulating valve is configured to regulate the supply of the pressurized hydraulic fluid based on the line pressure.

A system (10) for moving a fluid (12) includes a flow-circuit element (30) and a control system (32) that monitors an operational condition of the flow-circuit element (30). The control system (32) includes a first sensor (82) that monitors a first sensed condition, and a second sensor (84) that monitors a second sensed condition that is different from the first sensed condition. Further, the control system (32) includes a processor (76) that analyzes the first sensed condition and the second sensed condition to monitor the operational condition of the flow-circuit element (30).

A power transfer unit includes a first hydraulic circuit, a second hydraulic circuit fluidly connected to the first hydraulic circuit, a pump and motor assembly fluidly connected between the first hydraulic circuit and the second hydraulic circuit, an isolation valve arranged along the first hydraulic circuit and fluidly connected to an inlet of the pump and motor assembly. The isolation valve is movable between a closed position and an open position to prevent and enable high-pressure fluid flow to the inlet, respectively. An unloader valve is arranged along the second hydraulic circuit and fluidly connected to an outlet of the pump and motor assembly, and an orifice is arranged along the second hydraulic circuit and fluidly connected to the unloader valve to reduce back pressure in the second hydraulic circuit.

A balancing valve includes four ports. While the pressures at a pair of balancing ports of a hydraulic balancing valve are equal, the valve maintains two other ports in a closed position. Upon a pressure differential between the balancing ports, fluid communication can occur between one of the balancing ports and either of the other ports based upon the direction of the pressure differential. A hydraulic ride control system utilizes the balancing valve together with other control valves to provide ride control functionality.

A method of controlling hydraulic fluid flow to an implement of a material handling vehicle includes coupling a boom arm to a vehicle frame for rotation about the vehicle frame, rotating a boom arm with respect to the vehicle frame with an actuator, coupling an attachment to the boom arm for rotation with respect to the boom arm, sensing a pressure of fluid in the actuator, communicating the sensed pressure to a control system, determining a baseline pressure of the attachment based upon the sensed pressure of the fluid in the actuator, and limiting fluid flow to the actuator with a control valve in response to the sensed pressure of the fluid in the actuator being above the baseline pressure.

An example valve includes: a seat member; a spool configured to be seated on the seat member to block fluid flow from a first port to a second port when the valve is in a closed state, wherein fluid at the first port applies a fluid force on the spool; a spring applying a biasing force on the spool toward the seat member, wherein as the fluid force overcomes the biasing force, the spool moves in the proximal direction off the seat member, thereby allowing fluid flow from the first port to the second port through a flow area formed between the spool and the seat member; a turbine configured to rotate as fluid flowing through the flow area flows downstream across the turbine; and an electric generator coupled to the turbine, such that rotation of the turbine causes the electric generator to generate electric power.