A walking excavator (1) having a superstructure (2) and an undercarriage (29), and a cab (3) disposed on the superstructure (2), and four walking legs (4) pivotably disposed on the undercarriage (29), and an excavator arm (5) which is pivotably mounted on the superstructure (2) and to which an excavating tool (6), in particular an excavator bucket, is fastened or able to be fastened. A dual-action differential cylinder (7) pivots the excavator arm (5) up and down relative to the superstructure (2) and is articulated on the superstructure (2), on one side, and on the excavator arm (5), on an other side. For applying additional force along with the dual-action differential cylinder (7) when pivoting the excavator arm (5) down relative to the superstructure (2), a single-action differential cylinder (8) is additionally articulated on the superstructure (2), on one side, and on the excavator arm (5), on an other side.

A device for riveting and a hydropneumatic device for pressure transmission, including a working piston and a transmitter piston in the form of a double-acting cylinder for transmitting pressure to the working piston, wherein a working stroke of the working piston in a working direction includes a first stroke and a subsequent second stroke, wherein the first stroke is controlled by means of pneumatic pressure acting on the working piston and the second stroke is controlled by means of pneumatic pressure acting on the transmitter piston, and wherein hydraulic fluid is displaced by the transmitter piston and the displaced hydraulic fluid effects the second stroke of the working piston. Regulation means having an actuating device are provided for regulating the pneumatic pressure on both sides of the double-acting cylinder of the transmitter piston such that the second stroke of the working piston is predefined by way of the regulation.

A downforce control system for an agricultural ground engaging unit provides individual control of each agricultural ground engaging row unit by providing a proportional pressure control valve connected to the retracting chamber of a double acting cylinder which varies the upward force produced by the retracting chamber of the cylinder against a constant counteracting downward force produced by an extending chamber of the cylinder, the valve control based on a comparison of a sensed resultant downward force on the agricultural ground engaging row unit and a predetermined target downward force.

The improved hydraulic system utilizes a secondary hydraulic force control circuit that changes the gripping force on the load independently of movement of the clamp arms.

Working system for an application of force onto a workpiece, with a pneumatic actuator having an actuator housing designed to be fixed to a manipulator and a moveable element designed to couple an end effector and movably received on the actuator housing, and with a controller having a valve arrangement for a compressed air supply to the pneumatic actuator, has a position sensor system for determining a spatial position of the pneumatic actuator and for providing position-dependent electrical position sensor signals, and a processing system for processing the position sensor signals and for providing control signals to the valve arrangement, the processing system being designed for controlling a pneumatic supply to the pneumatic actuator as a function of the position sensor signals.

A header assembly for an agricultural harvesting machine comprises a first frame assembly, a second frame assembly that supports a cutter, and is movable relative to the first frame assembly, a float cylinder coupled between the first frame assembly and the second frame assembly, an accumulator, a controllable reservoir, and fluidic circuitry. The fluidic circuitry comprises a first conduit forming a first fluid path that provides a flow of pressurized fluid under pressure to the float cylinder, so the float cylinder exerts a float force on the second frame assembly, a valve mechanism that is actuatable to inhibit fluid flow along the first fluid path between the accumulator and the float cylinder, a second conduit forming a second fluid path fluidically coupled to the controllable reservoir, the controllable reservoir being controllable to add fluid to the float cylinder.

Disclosure herein are hydraulic systems and method of use thereof. The hydraulic systems can include a hydraulic cylinder and a manifold. The hydraulic cylinder can have a first end and a second end. The hydraulic cylinder can include a first port, a second port, and a third port. The first port can be located proximate the first end. The second port cane be located proximate the second end. The third port can be located in between the first port and the second port. The manifold can include a first valve and a second valve. The first valve can be in fluid communication with the first port and the third port. The second valve can be in fluid communication with the second port and the third port.

A hydraulic machine unit that can be operated with various working forces, in which working medium is selectively delivered, via a pump-piston accumulator system, to a main cylinder and at least one driving cylinder, wherein at least for one working stroke a pump system of the pump-piston accumulator system is used to provide working medium to a piston accumulator of the pump-piston accumulator system, and then at least for the working stroke at least the main cylinder is charged with a working pressure from the piston accumulator, and wherein at least for a return stroke the at least one driving cylinder is charged with a return stroke pressure from the pump-piston accumulator system, can be of structurally simple configuration if, at reduced working forces, the working pressure is reduced with respect to the piston accumulator pressure prevailing in the piston accumulator.

An artificial muscle stack that includes a plurality of artificial muscle layers. Each artificial muscle layer includes one or more artificial muscles having a housing with an electrode region and an expandable fluid region, a dielectric fluid housed within the housing, and an electrode pair having a first and second electrode positioned in the electrode region. The first and second electrodes each include two or more tab portions and two or more bridge portions. The two or more bridge portions interconnects adjacent tab portions. At least one of the first and second electrode includes a central opening positioned between the tab portions and encircling the expandable fluid region. The plurality of artificial muscle layers are arranged such that the expandable fluid region of the artificial muscles of each artificial muscle layer overlaps at least one tab portion of one or more artificial muscles of an adjacent artificial muscle layer.

A linear actuator system includes a linear actuator and at least one integrated pump assembly connected to the linear actuator to provide fluid to operate the linear actuator. The integrated pump assembly includes a pump with at least one fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to exclusively adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.