Abstract: A liquid-pressure driving system includes: a pump connected to an actuator through two pressure liquid passages; pressurizing mechanisms interposed on the passages and applying pressure to the operating oil returning from the actuator; a low pressure selector valve connected to parts of the passages and introducing to a cooling passage the operating liquid having lower pressure between the operating liquids flowing through the two pressure liquid passages; a restrictor mechanism interposed on the cooling passage; a cooler apparatus interposed on the cooling passage downstream of the restrictor mechanism, the cooler apparatus cooling the operating liquid flowing through the cooling passage; and a pressure liquid returning mechanism connected to parts of the two pressure liquid passages, each of the parts being at one side of the corresponding pressurizing mechanism close to the pump, the pressure liquid returning mechanism returning the cooled operating liquid to the two pressure liquid passages.

Abstract: A control system for construction machinery, includes a hydraulic pump, first and second actuators connected to the hydraulic pump through first and second parallel lines respectively, first and second control valves installed in the first and second parallel lines respectively and configured to control operations of the first and second actuators, first and second spool displacement adjusting valves configured to control displacement amounts of the spools of the first and second control valves, and a controller configured to output a control signal to the first and second spool displacement adjusting valves corresponding to a manipulation signal of an operator, and configured to limit a spool displacement amount of the second control valve according to the manipulation signal for the first actuator when the manipulation signal for a multiple operation of the first and second actuators is received.

Abstract: A rotary electrohydraulic actuator includes a direct drive hydraulic motor having an output shaft through opening that is concentric with a rotational axis of a rotor of the hydraulic motor. The actuator includes a power plant mounted on the hydraulic motor via a manifold. The power plant includes an electric motor driven hydraulic pump. Operation of the electric motor causes the hydraulic pump to supply pressurized fluid to the hydraulic motor. The power plant is compactly mounted to the manifold so that a longitudinal axis of the electric motor is parallel to and spaced apart from the rotational axis of the hydraulic motor.

Abstract: A hydraulic reservoir (10), for use for example in a marine pleasure craft, comprises a vortex chamber (16), a hydraulic fluid return line (18) and a hydraulic fluid suction line (20) respective entering and exiting substantially tangentially to an internal wall surface of the vortex chamber. An upper chamber (26) is disposed above the vortex chamber (16) and in fluid communication with the vortex chamber. The upper chamber is capable of expansion and/or contraction in use in order to adjust continuously to the volume of the hydraulic fluid to be accommodated in the hydraulic reservoir. Also disclosed is a method of operating such a hydraulic reservoir, in which hydraulic fluid is directed into the vortex chamber (16) along the hydraulic fluid return line (18) and extracting hydraulic fluid from the vortex chamber along the hydraulic fluid suction line (20), to thereby generate a vortex flow in the vortex chamber. Dissolved air, if present, becomes entrained into bubbles which rise to the upper chamber (26).

Abstract: The invention relates to a hydraulic fluid power transmission comprising: actuator apparatus having a plurality of chambers, each of the chambers having a respective fluid driving surface configured to drive or be driven by hydraulic fluid therein; a discretised pressure control system configured to selectively connect one or more first chambers of the said plurality of chambers to one of a plurality of hydraulic fluid sources or sinks, at least two of the plurality of hydraulic fluid sources or sinks having different fluid pressures; a continuous pressure control system configured to control the pressure of hydraulic fluid, or a flow rate of hydraulic fluid, input to or output from one or more second chambers of the said plurality of chambers, the pressure or flow rate of the hydraulic fluid input to or output from the second chambers being thereby variable within a range of pressures or flow rates respectively; and a controller configured to control the discretised and continuous pressure control systems to

Abstract: A piston structure body includes: a piston that includes a through hole, an inner circumferential portion, and an outer circumferential portion, the through hole being a hole that is formed to penetrate the piston axially through a center of a first face that is an end face on one end side in an axial direction, the inner circumferential portion defining the through hole and connected to the first face, the outer circumferential portion disposed to surround the inner circumferential portion and connected to the first face; and a piston rod that is inserted through the through hole. A first end face that is an end face of the inner circumferential portion on a back face side of the first face is positioned more closely to the first face than a second end face that is an end face of the outer circumferential portion on the back face side.

Abstract: A hydroelectric power system can include: a first level including a drain system, the drain system including a bell siphon coupled to a mixed flow turbine and a cross flow turbine, the drain system configured to provide a path way for a working fluid to flow from the bell siphon, through the mixed flow turbine, and through the cross flow turbine; and a second level below the first level, the second level for receiving the working fluid from the cross flow turbine of the drain system of the first level.

Abstract: An electric vacuum pump applied to a vacuum boosting brake system is provided. The pump has a water containing capacity that is greater than a backflow water capacity of an internal space defined in a pump housing which forms vacuum pressure. The pump includes a watertight chamber that is coupled to an exhaust port of a pump housing.

Abstract: A bicycle operating device comprises a base member, an operating member, a hydraulic unit, an electrical switch, a wireless communicator, and a power supply. The base member includes a first end and a second end opposite to the first end. The operating member is pivotally coupled to the base member about a first pivot axis. At least part of the hydraulic unit is disposed closer to the second end than the first pivot axis when viewed from a first direction parallel to the first pivot axis. The power supply is electrically connected to the wireless communicator to supply electrical power to the wireless communicator. At least one of the wireless communicator and the power supply is at least partly disposed closer to the first end than the first pivot axis when viewed from the first direction.

Abstract: A rotary displacement piston pump is disclosed having rotatable single or dual valve/port plate(s). The valve plate, being rotatable forward and/or rearward with respect to the rotation of the piston carrier, alters the phasing of the land area of the pumping action thereby altering the phasing of piston speed inasmuch as the land area can be moved to a position to accelerate the piston(s) in a pre or decompression phase. In this way, pump noise, from colliding pressure fronts within the respective high and low pressure plenums, can be “tuned” out of the pump by adjusting the phasing and position of the valve plate(s) and raising or lowering the pre and decompression pressure(s) as necessary. Pump volume can also be controlled by advancing or retarding the valve plate(s), either in or out of synch, so as to shorten intake/exhaust piston stroke and overlap fluid flow between respective intake/exhaust plenums.

Abstract: A road machine includes a travel switch to cause the road machine to start traveling, a hydrostatic transmission including a traveling hydraulic pump and a traveling hydraulic motor, a pump regulator to control the discharge quantity of the traveling hydraulic pump; and a controller to control the pump regulator using a pump command current. The pump regulator increases the discharge quantity of the traveling hydraulic pump as the pump command current increases, and the controller increases the pump command current to a predetermined value smaller than a maximum current value in response to the travel switch being turned ON. Alternatively, the pump regulator increases the discharge quantity of the traveling hydraulic pump as the pump command current decreases, and the controller decreases the pump command current to a predetermined value greater than a minimum current value in response to the travel switch being turned ON.

Abstract: A plunger tool and method relating thereto is designed to remove and insert plungers of a reciprocating pump such as during maintenance and other disassembly operations. The tool has a guide which receives and supports the plunger after removal from, and before reinsertion into, the pump. The tool also has a rack and pinion actuator for moving the plunger.

Abstract: A robot for navigating an environment through growth is provided. The growing robot has a thin-walled, hollow, pressurized, compliant body that elongates the body by everting from its tip new wall material that is stored inside the body. The robot controls the shape of the body by actively controlling the relative lengths of the wall material along opposing sides of the body allowing steering.

Abstract: The present disclosure discloses a hydraulic machine including a support assembly and a main cylinder device connected with the support assembly. The main cylinder device includes at least two main cylinder assemblies and at least two piston rods respectively. The at least two piston rods are opposite to each other and move along opposite directions and on the same straight line. A support worktable device is disposed on the support assembly and spaced with the main cylinder device. At least two pressing mechanisms are formed between the support worktable device and the at least two main cylinder assemblies or between the support worktable device and the at least two piston rods. The at least two pressing mechanisms are configured for pressing work pieces simultaneously.

Abstract: A lubricating sealing system for a fluid end includes a fluid end, a sleeve, a plunger, and a lubrication system. The sleeve is coupled to an internal surface of the fluid end. The plunger reciprocates in a linear manner through the sleeve and into a pressure chamber of the fluid end. The lubrication system is in communication with the plunger and configured to provide lubricant through an interior of the plunger for routing to surfaces between the plunger and the sleeve. The lubricant is pressurized and moved via the reciprocating of the plunger and create a positive pressure on the lubricant over the pressures experienced in the pressure chamber of the fluid end. The positive pressure creates a barrier and pushes away contaminants from the plunger seals thereby avoiding wash out.

Abstract: A linear actuator system includes a linear actuator including an outer body, an inner body disposed within the outer body, a fluid chamber at least partially extending between the inner body and the outer body, a piston chamber extending at least partially within the inner body, a valve configured to selectively fluidly couple the fluid chamber and the piston chamber to each other, a piston assembly including a piston, a variable volume within the piston chamber that extends between the piston and the valve, and a gas collector assembly including a fluid passageway. The piston assembly is disposed within the piston chamber, wherein a movement of the piston assembly causes a gas separated from a liquid within the variable volume to flow through the fluid passageway, through the valve, and into the fluid chamber.

Abstract: Described herein is a safety valve for a hydraulic circuit comprising a pump designed to supply a hydraulic fluid at a first pressure value to a pressure line, comprising: a chamber, which can be fluidically connected to the pressure line and is filled with the hydraulic fluid at a pressure value and a temperature value; and a casing with an opening, which can be connected to a reservoir of the hydraulic circuit; a shutter, which delimits the first chamber and can be displaced between a first position, in which it occludes the first opening, and a second position, in which it leaves the opening at least in part free; the valve comprises a thermally expandable element, which can be displaced, as a result of the temperature of the hydraulic fluid, between a first configuration that it assumes when the temperature of the hydraulic fluid is below the threshold value and a second configuration that it assumes when the temperature of the hydraulic fluid is above the temperature threshold value and in which it holds

Abstract: The subject matter of this specification can be embodied in, among other things, an articulated joint includes a first rotary actuator having a first housing defining a first arcuate chamber comprising a first cavity, and an arcuate-shaped first piston having a first radius of curvature and disposed in said first housing for reciprocal movement in the first arcuate chamber, a second rotary actuator having a second housing defining a second arcuate chamber comprising a second cavity, and an arcuate-shaped second piston having a second radius of curvature and disposed in said second housing for reciprocal movement in the second arcuate chamber, wherein a first radial side of the first piston relative to the first radius of curvature is in bearing contact with a first radial side of the second piston relative to the second radius of curvature at a contact point between the first axis and the second axis.

Abstract: The present invention relates to a work machine having at least one hydraulic actuator for actuating a piece of working equipment and having a first displacement unit that is driven by a drive assembly of the work machine and that feeds the hydraulic actuator with hydraulic medium from a hydraulic tank, wherein at least one second displacement unit is provided that is driven by the drive assembly and that feeds the hydraulic actuator and/or further hydraulic consumers with hydraulic medium from a hydraulic tank in the working mode and that is drivable during a recovery mode by the hydraulic volume displaced by the at least one hydraulic actuator or by a hydraulic consumer to feed kinetic energy back to the drive assembly.

Abstract: A hydraulic rotational drive for rotating load-handling equipment relative to a crane arm includes a shaft, which has a first securing element for connecting the shaft to the load-handling equipment or the crane arm, a shaft bearing, which has second securing element for connecting the shaft bearing to the crane arm or the load-handling equipment, vanes arranged in the shaft which can be acted on by oil via an oil feed, and an oil discharge for the transmission of a torque to the shaft. The rotational drive also has a rotary encoder for the detection of the angular position of the shaft relative to the shaft bearing.