Abstract: A fluid cylinder includes an outer cylinder surrounding expandable intermediate and inner cylinders. A first sealed volume is defined between the outer cylinder and the intermediate cylinder, a second sealed volume is defined between the intermediate cylinder and the inner cylinder and a third volume defined within the inner cylinder. The first sealed volume is held at a lower pressure than the second and third volumes. At upper heights of the intermediate and inner cylinders, the pressures of the second and third volumes are approximately equal. Exerting a downward force on a linkage connected to a top end of the inner cylinder results in changes in pressure-volume relationships, causing the intermediate cylinder to fall and, upon release of the downward force, causing the intermediate and inner cylinders to rise again to their upper heights. The reciprocal motion generated can be harnessed for various purposes.

Abstract: An exemplary embodiment of the present disclosure relates to a construction machine starting assist system including: an engine of a construction machine; an input unit which receives a key-on signal and a key-off signal of the engine; a hydraulic pump which is operated by the engine; an actuator which is operated by hydraulic oil discharged from the hydraulic pump; a regeneration valve which is switched so that a part or an entirety of the hydraulic oil returned from the actuator; an accumulator which is charged with the hydraulic oil supplied from the regeneration valve; a charging valve which is controlled so that the hydraulic oil is discharged from the accumulator when the key-on signal is inputted into the input unit; and a hydraulic motor connected to the engine and configured to assist in starting the engine.

Abstract: A hydraulic drive for feed rollers of a head of a complete timber harvester includes two radial piston motors coupled for conjoint rotation to the feed rollers. One radial piston motor has only one displacement volume and the other radial piston motor has two displacement volumes, between which it is possible to switch. A tree trunk clamped between the feed rollers can thus be moved at two speeds. At the higher speed, pressure medium circulates under a control pressure in the second displacement volume of the switchable radial piston motor.

Abstract: A hydrostatic drive, as a whole system, includes two fluidic displacement units (1, 3), which can be adjusted at least in respect of the volumetric flow. One unit is coupled to an input (9). The other unit is coupled to an output (11). The units can be connected to each other in the manner of a closed fluidic circuit, to which a storage circuit (23) is connected. The storage circuit has at least one storage device (33), is divided into a low-pressure side (27) and a high-pressure side (25), and has a valve control (17) for controlling the whole system.

Abstract: An energy regeneration device capable of controlling flow of a working fluid discharged from an actuator while regenerating energy from the working fluid, and a work machine including the foregoing device, include a boom cylinder, an inertial fluid container, an oil tank, an accumulator, a low-pressure-side opening/closing device, and a high-pressure-side opening/closing device. A calculation unit calculates a duty ratio for opening/closing the low-pressure-side opening/closing device and the high-pressure-side opening/closing device in accordance with a desired flow rate of a hydraulic fluid discharged from the boom cylinder. A regeneration control unit selects alternately the low-pressure-side opening/closing device and the high-pressure-side opening/closing device as a destination with which the inertial fluid container communicates in accordance with the calculated duty ratio, and supplies the discharged hydraulic fluid to an accumulator.

Abstract: The invention relates to a telescopic actuator comprising a cylinder (1) having a closed end (2) and an open end (3) for passing a hollow rod (4) mounted to slide axially in the cylinder.

Abstract: An actuator includes an actuator piston movable along an axis, a first stop member rotatable about the axis and configured to limit the movement of the actuator piston in a first direction along the axis, a second stop member movable along the axis and configured to limit the movement of the actuator piston in a second direction along the axis, wherein the first direction is opposite to the second direction. A first screw connection is present between the first stop member and the second stop member such that rotation of the first stop member about the axis causes movement of the second stop member along the axis to vary the amount by which the actuator piston can move along the axis in use.

Abstract: The hydraulic pressure generating device includes a regulator (spool valve) formed by a cylinder body, a spool which slidably moves within the cylinder body, a pilot chamber in which a pilot pressure which is a hydraulic pressure moving the spool along in an axial direction is inputted and an output chamber out of which an output pressure which is a hydraulic pressure corresponding to the pilot pressure is outputted, wherein the hydraulic pressure generating device further includes a spool position obtaining portion which obtains a relative position of the spool relative to the cylinder body and a pilot pressure controlling portion which controls the pilot pressure based on the relative position obtained by the spool position obtaining portion.

Abstract: A failsafe piston retention assembly, and related components, systems, and methods are disclosed. A failsafe piston retention assembly comprises a head comprising a head body having a first surface. The assembly also includes a piston having second surface, the piston slidably coupled with respect to the head. The piston has a retracted configuration and an unretracted configuration. In the retracted configuration, the second surface is fixed with respect to the first surface by a magnetic force. One advantage of this arrangement is that the piston is retained in its retracted configuration in the event of an operational failure of the piston mechanism. For example, for a hydraulically controlled piston, the magnetic force retains the piston in a retracted configuration even in the event of a loss of hydraulic pressure.

Abstract: 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.

Abstract: Devices and systems for producing rotational actuation are described. More specifically, hydraulic and pneumatic actuators that can produce and control rotational or joint-like motion are described. An actuator may be configured to allow parallel coupling of multiple actuators, and thus increase the range of rotation of the actuators when considered collectively.

Abstract: A steel piston for coupling to a connecting rod and wrist pin is provided. The piston includes a body with an upper crown presenting a combustion surface for exposure to a combustion chamber. The upper crown presents an undercrown surface which is openly exposed as viewed from an underside of the piston and not bounded by a cooling gallery. The body includes a ring belt and pin bosses depending from the ring belt and presenting a pin bore for receiving the wrist pin. The body also includes ribs disposed along the undercrown surface. The body includes a ratio of compression height to outer diameter (CH/D) ranging from 34.8% to 42.0%. The piston also includes a low heat transfer coating on the combustion surface, and the low heat transfer coating has a thermal conductivity of about 0.20 to 0.80 W/m·K.

Abstract: A car wash system including a hydraulic pump, the pump being overcapacity for the rotating cleaning elements to which it is connected. An output from the hydraulic pump is connected to a hydraulic motor, which is, in turn, connected to a generator. The generator is connected to a service panel. Thus, some of the spare capacity of the hydraulic pump may be used to generate electricity which may be returned to the grid, reducing operating costs of the automated car wash.

Abstract: An expansion chamber for a rotary vane vacuum pump is provided. The expansion chamber is in fluid communication with the discharge side of the rotary vane vacuum pump, such that the expansion chamber attenuates sound as a Helmholtz resonator. The expansion chamber includes an internal volume of between 80 cubic centimeters and 100 cubic centimeters, inclusive, and includes a curved sidewall that extends partially around, and generally conforms to, the exterior of the rotary vane vacuum pump. The expansion chamber also includes a downward extending port, open to the atmosphere, for attachment to a hose in applications in which the expansion chamber is below a water line.

Abstract: A fluid cylinder includes an outer cylinder surrounding expandable intermediate and inner cylinders. A first sealed volume is defined between the outer cylinder and the intermediate cylinder, a second sealed volume is defined between the intermediate cylinder and the inner cylinder and a third volume defined within the inner cylinder. The first sealed volume is held at a lower pressure than the second and third volumes. At upper heights of the intermediate and inner cylinders, the pressures of the second and third volumes are approximately equal. Exerting a downward force on a linkage connected to a top end of the inner cylinder results in changes in pressure-volume relationships, causing the intermediate cylinder to fall and, upon release of the downward force, causing the intermediate and inner cylinders to rise again to their upper heights. The reciprocal motion generated can be harnessed for various purposes.

Abstract: A braking device for a vehicle, in particular a motor vehicle, including an actuatable brake pedal, a piston of a master brake cylinder mechanically coupled to the brake pedal, the piston being supported in the master brake cylinder so as to be axially displaceable in an actuation direction and in a release direction, and including at least one radial seal that acts between the piston and the master brake cylinder. At least one elastically deformable and/or displaceable damping element opposes the displacement of the piston in the release direction.

Abstract: In an elastic tube as a driving force source of a fluid pressure actuator that is driven by supplying and discharging fluid such as air or liquid, a wear-resistant flocked layer is provided on an entire outer circumferential surface of the elastic tube, and the wear-resistant flocked layer being formed by an electrostatic flocking process in which short fibers made of synthetic resin are flocked to be perpendicular to the outer circumferential surface, and the wear-resistant flocked layer being further formed by the electrostatic flocking process in which the short fibers made of the synthetic fiber are flocked in a number of strips along an axial direction or in a number of dots on the entire outer circumferential surface.

Abstract: A hydraulic cylinder includes a cylinder tube, a piston, a piston rod, a bearing, and a seal, wherein the seal is configured to allow the flow of the operating liquid from the rod side chamber toward the anti-rode side chamber through the through passage when the pressure in the rod side chamber is higher than the pressure in the anti-rod side chamber.

Abstract: A compensator device includes a hydraulic cylinder with a first end, a second end and an inner cylinder rod extending axially from the second end; and a piston rod with a piston movable axially within the cylinder. The inner cylinder rod has an end with a blocking diameter. The piston rod is generally hollow and includes a cavity to receive the blocking diameter of the inner cylinder rod.

Abstract: An example method includes identifying an operating state at which a velocity of a hydraulic actuator configured to operate a movable member of a robot is less than a threshold velocity and an actuator force is less than a threshold force, determining a valve command that corresponds to the operating state, such that the valve command is provided to a valve configured to control flow to and from the hydraulic actuator, and the valve includes a spool movable within a body of the valve, and the valve command causes the spool to move within the body of the valve to a position that induces the operating state, and determining a null bias signal based on the valve command.