Abstract: Provided is a construction machine allowing regeneration of a return hydraulic fluid at the time of both a boom raising operation and a boom lowering operation with a small number of valves, making it possible to secure a satisfactory operability at the time of both the boom raising operation and the boom lowering operation.

Abstract: A fuel pump for an internal combustion engine is provided comprising a barrel including a central bore having a longitudinal axis, a plunger disposed partially in the central bore and movable along the longitudinal axis, a spring retainer, a first coil spring having a proximal end in contact with a first section of the barrel and a distal end in contact with the spring retainer to urge the spring retainer into engagement with a tappet assembly, an extender element coupled to the plunger, and a second coil spring having a proximal end in contact with a second section of the barrel and a distal end in contact with the extender element to urge the plunger toward the spring retainer, wherein the extender element includes a counter-bore to couple the extender element to the plunger.

Abstract: A double-acting hydraulic cylinder has a first cylinder housing and a piston guided in the first cylinder housing, wherein a first pressure chamber and a second pressure chamber are provided in the first cylinder housing and are additionally separated from one another by the piston. A first connector serves to feed a hydraulic liquid to the first pressure chamber, and a second connector serves to feed the hydraulic liquid to the second pressure chamber. A second cylinder housing surrounds the first cylinder housing at least in one section. The first connector and the second connector may be arranged at an end of the double-acting hydraulic cylinder which faces away from the second pressure chamber. The second pressure chamber may be loaded with the hydraulic liquid via the section in which the second cylinder housing surrounds the first cylinder housing.

Abstract: A hydraulic cylinder includes a cylinder having axially spaced-apart first and second bores, and a piston having a piston rod and arranged in the cylinder for movement between two end positions and dividing the cylinder into a piston side and a piston-rod side. A hydraulic pump pumps hydraulic oil into the piston side to move the piston from one end position toward the other end position while hydraulic fluid is discharged from the piston-rod side via the first bore and a first outlet line. A throttling device is operably connected to the cylinder to throttle a flow of the hydraulic fluid as the piston moves past and seals the first bore so that hydraulic fluid is discharged via the second bore, thereby reducing a delivery amount of the hydraulic oil and thereby braking and damping a movement of the piston toward the other one of the end positions.

Abstract: A hydraulic system according to the present invention includes a rotational shaft, a hydraulic rotor supported by the rotational shaft so as to be incapable of relative rotation, an output adjuster varying a volume of the hydraulic rotor, a control shaft tilting the output adjuster, a drive motor operating the control shaft around the axis, a drive shaft disposed on a reference axis same as the axis of the control shaft and operably driven around the axis by the drive motor, a deceleration mechanism decelerating rotary power input from the drive shaft and outputs the decelerated rotary power toward the control shaft, and a housing accommodating the hydraulic rotor, the output adjuster, and the deceleration mechanism, wherein the deceleration mechanism has a hypocycloid-type deceleration mechanism disposed on the reference axis.

Abstract: A hydraulic control system includes a variable displacement hydraulic pump, the pump having an inlet for receiving fluid, an outlet for discharging fluid under pressure, and a pump displacement input, a hydraulic motor having an inlet and an outlet a fluid circuit including a supply conduit for conducting fluid discharged by the pump to the motor and a return conduit for returning fluid discharged by the motor to the pump, a pump displacement control cooperating with the pump displacement input in order to vary a displacement of the pump, a control circuit in communication with the pump displacement control for controlling the pump output such that the motor is driven at a constant rotational speed and at least two valves controlling a rotational speed of the motor, wherein one of the valves provides coarser flow control resolution and another of the valves provides finer flow control resolution.

Abstract: The invention relates to an autonomous device (10) for storing and releasing energy in order to power a piece of electrical equipment (12), in particular a piece of electrical equipment (12) of an aircraft, characterised in that said device comprises: a first means (16), configured to transform a variation in the surrounding pressure (P) to which the device (10) is subject into mechanical energy, at least one second means (20, 22), configured to mechanically store said mechanical energy by transforming same into the form of mechanical potential energy, a third means (24), configured to control the release of the mechanical potential energy contained in said second means (20, 22) and transform same into restored mechanical energy, a fourth means (28), configured to transform the restored mechanical energy into electrical energy suitable for powering said piece of electrical equipment (12).

Abstract: An articulated coupling is provided for a piston sealing device for a piston which includes a fixed skirt and a sliding skirt interconnected by a mechanical inter-skirt connection for axially compressing a continuous extensible segment under the action of a sliding skirt spring, the coupling replacing, on the one hand, the fixed skirt by a ball-joint skirt and providing, on the other hand, a troncospherical piston end which cooperates with a skirt troncospherical bearing surface provided on the ball joint skirt while an articulation unit interposed between the inter-skirt mechanical connection and the piston and/or between the connection and the sliding skirt.

Abstract: In a drive device using a hydraulic pump controlled by a rotatable swash plate, the swash plate includes a pocket and a trunnion engaged to the pocket and rotatable about an axis of rotation offset from the swash plate axis of rotation. An interface is formed on a first end of the trunnion, and a first arcuate side of the interface engages a flat portion of the first side of the pocket as the trunnion is rotated in a first direction, and a second arcuate side of the interface engages a flat portion of the second side of the pocket as the trunnion is rotated in the opposite direction. The swash plate may also include at least one protrusion on a top surface extending in a direction perpendicular to swash plate axis of rotation to engage the housing and limit axial movement of the swash plate.

Abstract: A piston plug includes a cylindrical body having a longitudinal axis and an outer cylindrical surface. The outer cylindrical surface extends longitudinally between a first surface and a second surface opposite the first surface. The outer cylindrical surface defines a hole extending radially inward. The hole has a central axis perpendicular to the longitudinal axis of the cylindrical body. A first channel and a second channel are defined by cylindrical body. The first channel is in fluidic communication with the first surface and the hole. The second channel is in fluidic communication with the second surface and the hole. The first channel, the second channel, and at least a portion of the hole form a non-collinear flowpath. The piston plug is disposed in a plug hole in a piston and is retained in the plug hole via an interference fit between the piston plug and the plug hole.

Abstract: A piston rod and a rod cover which constitute this hydraulic cylinder are configured from aluminum or an aluminum alloy. An alumite coating film is formed on at least a part of the inner wall surface of the rod cover that constitutes a rod insertion hole, and a diamond-like carbon coating film is formed on the outer wall surface of the piston rod, said diamond-like carbon coating film being in sliding contact with the alumite coating film.

Abstract: Disclosed and claimed is a double-acting cylinder comprising a cylinder housing, a first floating piston, a second floating piston and a central piston which is movable to three stationary positions along an actuation direction of the cylinder. A movement of the floating pistons in the cylinder bore is delimited by end stop arrangements. A movement of the central piston in the cylinder bore is delimited by the first and the second floating piston. Each floating piston comprises a first section and a second section. A circumferential length of the floating pistons is greater in the first section than in the second section. In the first sections a first seal is arranged for a sealing engagement with an inner wall of the cylinder bore. In the second sections a second seal is arranged for a sealing engagement with the inner wall of the cylinder bore or an inner wall of the central piston.

Abstract: A telescopic pneumatic linear actuator, particularly for unwinders with movable arms, includes a first annular cylinder, provided with a respective cavity, and a second annular cylinder, which can be inserted into and can slide within the cavity of the first annular cylinder and is provided with a respective cavity. The actuator also includes an annular piston, which can be inserted into and can slide within the cavity of the second annular cylinder. The first and second annular cylinders and the annular piston are provided with respective holes for the passage of a self-expanding spindle.

Abstract: A fan drive system includes a hydraulic pump, a hydraulic motor that rotates a fan on the basis of hydraulic oil supplied from the hydraulic pump, a data acquisition unit that acquires an actual fan speed of the fan, a target amount determination unit that determines a target fan speed of the fan on the basis of a state of an object to be cooled of the fan, and an estimating unit that estimates a state of the hydraulic pump or a state of the hydraulic motor on the basis of a change of a feedback amount that indicates a difference between the target fan speed and the actual fan speed.

Abstract: A gas cylinder, in particular a high-pressure gas cylinder, includes a cylinder tube (1) having a piston rod (9) that is passed through a sealing arrangement (13) by which the gas pressure prevailing in the pressure chamber (23) of the cylinder tube (1) is sealed off against the ambient pressure. The sealing arrangement (13) has a compressed oil chamber (33) between a sealing element (31) adjacent to the pressure chamber (23) and another sealing element further away from the pressure chamber (23). Oil can be pressed in the oil chamber by a supply device (51) at a pressure that is equal to or higher than the respective gas pressure prevailing in the pressure chamber (23) of the cylinder tube (1).

Abstract: A hydrostatic transmission for a traction drive includes a first hydraulic machine that is coupled to a drive machine and that has an adjustable displacement volume and a second hydraulic machine that is fluidically connected to the first hydraulic machine and that is coupled to a drive output of the traction drive. At the first hydraulic machine, a control pressure acts in the direction of an enlargement of its displacement volume and a working pressure of the second hydraulic machine acts in the opposite direction. The hydrostatic transmission further includes a control device that varies the control pressure to influence a torque of the second hydraulic machine. The control device stores a characteristic map by which a setpoint control pressure is determined as a function of a setpoint torque and a displacement volume of the second hydraulic machine so as to regulate the torque of the second hydraulic machine.

Abstract: Provided is a hydraulic drive system for a work machine configured with a single solenoid proportional valve for a regeneration circuit, wherein substantially the same actuator speed can be secured irrespective of whether or not hydraulic fluid discharged from a hydraulic actuator is regenerated for driving of another hydraulic actuator.

Abstract: An apparatus and control system of a programmable air servo motor includes an air servo motor and an air servo motor driver, which are bi-directionally communicable with each other via communication units. The air servo motor includes an air motor, a sensor module, and a brake module that is normally locked and can be unlocked or locked by the air servo motor driver. The air servo motor driver includes a control module, an actuation module and a communication module. After actuating the air servo motor, the air servo motor driver receives torque, rotational speed and angle signals output by the sensor module. The actuation module drives the air servo motor to stop emergently, switch between forward and reverse rotation, increase or reduce rotational speed, operate at a specific angle, move by inching and operate at controlled torque similar to an electric servo motor without the need of an encoder.

Abstract: Provided is a hydraulic control system for a construction machine, including: a control valve (31) for controlling supply and discharge of hydraulic fluid to and from an arm cylinder (4); an operation lever (6) for controlling the position of a spool of the control valve (31); a meter-out flow passage (34) for passing therethrough hydraulic fluid discharged from the arm cylinder; a variable restrictor (23a) provided in the meter-out flow passage; pressure sensors (41, 42) for detecting a magnitude of a negative load applied by an external force to the arm cylinder in a same direction as an actuation direction of the arm cylinder; and a controller (45) for reducing an opening area of the variable restrictor (23a) according to an increase in the magnitude of the negative load calculated with a detection value from the pressure sensors (41, 42).

Abstract: A hydrokinetic torque coupling device for coupling together driving and driven shafts, comprises a casing, impeller and turbine wheels, a torsional vibration damper, a turbine hub non-rotatably connected to the turbine wheel, and first and second vibration absorbers. Each of the first and second vibration absorbers is one of a dynamic absorber and a pendulum oscillator. The turbine hub is non-rotatably coupled to a driven member of the torsional vibration damper. The first vibration absorber is mounted to the turbine hub and the second vibration absorber is mounted to one of the turbine hub and the casing. The first vibration absorber and the second vibration absorber are tuned to address different orders of vibrations. The dynamic absorber includes an inertial member and a connecting plate coupled to the inertial member. The pendulum oscillator includes a support member and flyweights configured to oscillate relative to the support member.