Abstract: An excavator includes: a swing motor driven by oil from a swing pump coupled to a power take-off and driven by an engine; a first main oil passage connecting a first discharge port of the swing pump and a first suction port of the swing motor; a second main oil passage connecting a second discharge port of the swing pump and a second suction port of the swing motor; a neutral retention valve disposed in the first main oil passage and the second main oil passage and controlling passage of oil; a regenerative energy absorbing device coupled to the power take-off and absorbs regenerative energy generated by oil from the swing motor to the swing pump via a meter-out opening of the neutral retention valve; and a valve control section controlling an area of the meter-out opening based on a state of the regenerative energy absorbing device.

Abstract: Methods and systems for a hydromechanical transmission are provided herein. In one example, the transmission operating method includes asynchronously shifting between a first pair of drive ranges in the transmission via operation of two clutches and a variable displacement hydraulic pump in a hydrostatic assembly. In the method, asynchronously shifting between the two drive ranges includes a plurality of phases that include a swiveling phase where a speed of the hydrostatic assembly is inverted.

Abstract: An actuator for actuating a parking lock and for carrying out at least one other vehicle function in a motor vehicle includes a hydraulic unit and an actuation cylinder, rigidly connected to the hydraulic unit. The hydraulic unit has a hydraulic pump or valves driven by an electric motor. The actuation cylinder is for mechanically actuating a parking lock mechanism of the parking lock. In some embodiments, the actuator has an actuator housing and the actuation cylinder has a cylinder housing that is part of the actuator housing. In some embodiments, the actuation cylinder has a piston and an actuating element, movable via the piston, for actuating the parking lock mechanism.

Abstract: A hydraulic system includes: an arm hydraulic cylinder; a first hydraulic pump and a second hydraulic pump; an arm first direction switching valve; an arm second direction switching valve; and a controller that controls an operation of the arm second direction switching valve when the arm hydraulic cylinder is extended and operated. Further, the arm first direction switching valve incorporates an arm regeneration passage capable of supplying oil when the arm hydraulic cylinder is extended and operated, and the controller monitors a pressure state of the arm hydraulic cylinder, and when determining that oil flow through the arm regeneration passage is possible, the controller blocks oil flow between the arm hydraulic cylinder and the arm second direction switching valve, and otherwise, the controller operates the arm second direction switching valve so that oil can be supplied from the second hydraulic pump to the bottom chamber.

Abstract: The present disclosure relates to an apparatus and to a method for controlling a crane slewing gear. The apparatus comprises a hydraulic motor for driving the slewing gear and for braking the slewing gear from a rotational movement. The slewing gear is kept stationary via a holding brake. A hydraulic brake circuit for controlling the holding brake, a load sensing device for measuring a load instantaneously taken up by the crane, and an orientation sensing device for measuring an instantaneous orientation of the crane and/or of at least one crane component are furthermore provided. In accordance with the disclosure, a hydraulic limitation circuit is provided by means of which a hydraulic pressure applied to the motor can be limited to a specific limit value. A control unit is furthermore provided that determines a maximum permitted torque and/or a parameter derived therefrom for a current slewing gear movement.

Abstract: A work vehicle includes: an operation tool that is operated by an operator; and a controller that determines a target flow rate for hydraulic oil fed to a hydraulic device on a basis of the amount of operation of the operation tool. The controller calculates a bleed-off target flow rate on a basis of the flow rate of hydraulic oil fed from a hydraulic oil pump and the target flow rate for hydraulic oil fed to the hydraulic device, calculates a bleed-off throttle differential pressure on a basis of a pressure of hydraulic oil fed from the hydraulic oil pump and a pressure of hydraulic oil in a hydraulic oil tank, calculates a bleed-off target opening area on a basis of the bleed-off target flow rate and the bleed-off throttle differential pressure, and controls a hydraulic oil control valve such that the bleed-off target opening area is achieved.

Abstract: A fuel injector assembly can include a manifold defining a manifold channel and a nozzle extending from the manifold. The nozzle can be configured to direct flow from the manifold channel into a combustor. The nozzle can define a fuel inlet open to the manifold channel, a fuel outlet configured to be open to a combustor, and a throat fluidly connecting the fuel inlet to the fuel outlet. The assembly can include a trim device inserted into the manifold. The trim device can be configured to adjust flow between the manifold channel and the fuel inlet to adjust flow through the throat and out of the fuel outlet.

Abstract: Provided is a work machine which can increase the operation speed of an actuator by a regeneration function while securing the position control accuracy of the actuator. A controller is configured to calculate a regeneration flow rate on the basis of an input amount of an operation lever and a target actuator flow rate, subtract the regeneration flow rate from the target actuator flow rate to calculate a target actuator supply flow rate, calculate a target flow rate control valve opening amount on the basis of the target actuator supply flow rate, calculate a target pump flow rate that is equal to or higher than a total target actuator supply flow rate, control a selector valve on the basis of the input amount of the operation lever, control a flow rate control valve according to the target flow rate control valve opening amount, and control a hydraulic pump according to the target pump flow rate.

Abstract: A method for controlling the operation of a work vehicle includes initially controlling an operation of an implement actuator of the vehicle based on operator inputs received from an input device while a load sensing system of the vehicle is operable to adjust an output of an associated pump. The method also includes receiving an input providing an indication that an implement-based movement operation is to be performed and deactivating the load sensing system in response to the indication that the implement-based movement operation is to be performed. In addition, the method includes controlling the operation of the implement actuator based on further operator inputs received from the input device to perform the implement-based movement operation while the load sensing system is deactivated.

Abstract: A hydraulic system of a construction machine includes: control valves interposed between a variable displacement main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a regulator that changes a displacement of the main pump; and a second solenoid proportional valve connected to an auxiliary pump by a primary pressure line, the second solenoid proportional valve outputting a secondary pressure to the regulator through a secondary pressure line. A switching valve is interposed between the auxiliary pump and the first solenoid proportional valves, and includes a pilot port that is connected to the secondary pressure line by a pilot line.

Abstract: An example valve assembly includes a first workport fluidly coupled to a first actuator; a second workport fluidly coupled to the first actuator; a third workport fluidly coupled to a second actuator, wherein the third workport is fluidly coupled to the first workport via a first fluid passage; a fourth workport fluidly coupled to the second actuator, wherein the fourth workport is fluidly coupled to the second workport via a second fluid passage; and a spool axially movable in a bore within the valve assembly, wherein when the spool is shifted axially in a first axial direction, pressurized fluid is provided to the first workport and to the third workport via the first fluid passage, and when the spool is shifted axially in a second axial direction opposite the first axial direction, pressurized fluid is provided to the second workport and to the fourth workport via the second fluid passage.

Abstract: An excavator or other work machine includes a tilting bucket operated by a hydraulic actuator controlled by a bucket control valve responsive to control signals including a bucket shake control signal, which causes the bucket to move repeatedly in the rack and dump directions to shake debris from the bucket in a bucket shake operation. The actuator is powered by pressure from a hydraulic pump, and a control system includes an unloader valve to relieve pressure from the supply line to unload the pump when there is no demand for power. The control system is arranged to maintain a constant pressure signal in a load sensing line, to maintain the unloader valve constantly in a closed condition, for the duration of the bucket shake operation. This may be achieved by pressurising an actuator of a quick coupler to lock the bucket to the machine.

Abstract: An example valve assembly includes a first workport fluidly coupled to a first actuator; a second workport fluidly coupled to the first actuator; a third workport fluidly coupled to a second actuator, wherein the third workport is fluidly coupled to the first workport via a first fluid passage; a fourth workport fluidly coupled to the second actuator, wherein the fourth workport is fluidly coupled to the second workport via a second fluid passage; and a spool axially movable in a bore within the valve assembly, wherein when the spool is shifted axially in a first axial direction, pressurized fluid is provided to the first workport and to the third workport via the first fluid passage, and when the spool is shifted axially in a second axial direction opposite the first axial direction, pressurized fluid is provided to the second workport and to the fourth workport via the second fluid passage.

Abstract: A wheeled work vehicle includes: a transmission transmitting the rotational power of a traveling hydraulic motor to wheels; a traveling control valve having an interruption position that interrupts supply of hydraulic fluid from a hydraulic pump to the traveling hydraulic motor; a shift changeover valve that shifts the speed stage of the transmission by the position of the shift changeover valve being selectively switched; and a controller that controls the traveling control valve and the shift changeover valve. The controller switches the traveling control valve to the interruption position, then switches the position of the shift changeover valve such that the speed stage of the transmission is shifted to the low speed stage, and switches the traveling control valve from the interruption position to an original position side before the switching in a case where the controller shifts the transmission from the high speed stage to the low speed stage.

Abstract: A method of operating a driveline including a powersplit transmission is provided. The driveline may be operated in a hydrostatic power transmission mode and a blended hydrostatic/mechanical power transmission mode. The method comprises the steps of providing a hydrostatic circuit, detecting a rapid deceleration of the vehicle, and adjusting a threshold of at least one pressure relief valve forming a portion of the hydrostatic circuit in response to the sudden deceleration. The at least one pressure relief valve facilitates quickly changing the driveline from the blended hydrostatic/mechanical power transmission mode to the hydrostatic power transmission mode.

Abstract: The invention relates to a fluid valve arrangement having a bistable fluid valve for at least one fluid line with a valve body which can be moved into two positions for two switching states, a pressure pulse generator being provided for valve switchover in the feed line for switching over a feed line and a return line between two flow lines, and the fluid valve comprising a reversing unit which has two chambers which are separated from one another by a bistable surface element, the two chambers being connected to the two flow lines and the bistable surface element being operatively coupled to the valve body in order to actuate it. As a result, a bistable fluid valve is provided which can be reversed by way of pressure pulses or pressure flanks and otherwise has no energy requirement.

Abstract: An electro-hydraulic actuator (EHA) includes a hydraulic circuit having a plurality of pressure compensated flow control valves for limiting the maximum flow rate through the fluid conduits regardless of the loads imparted on the actuator. In one embodiment of the EHA, a plurality of combination manual override/thermal expansion valves that simplify the manufacture of the EHA.

Abstract: A hydraulic motor drive system is disclosed. The hydraulic motor drive system includes a pump, a flow control module fluidly coupled to a discharge of the pump via a first conduit, and a hydraulic motor fluidly coupled to the flow control module via a second conduit and a third conduit, and a controller operatively coupled to the flow control module. The controller is configured to operate the flow control module in a first mode, such that the flow control module blocks fluid communication between the pump and the hydraulic motor via the second conduit, and effects fluid communication between the pump and the hydraulic motor via the third conduit, and operate the flow control module in a second mode, such that the flow control module effects fluid communication between the pump and the hydraulic motor via the second conduit.

Abstract: An apparatus includes a first plurality of cylinders, each coupled to a shared first port by a separate first valve and to a shared second port by a separate second valve. Each first and second valve has a chamber to which pressure from either the associated cylinder or the respective port is dynamically applied to select different operating modes. Each one of a second plurality of cylinders is coupled to the first port by a separate third valve and to a shared third port by a separate fourth valve. Each third and fourth valve has a chamber to which pressure from either the associated cylinder or the respective port is dynamically applied to select different operating modes. Selecting an operating mode enables the apparatus to act as a bidirectional pump or a hydraulic motor. Selectively controller the valves can deactivate an individual cylinder, while other cylinders remain active.

Abstract: A hydraulic fan circuit includes a primary pump, a motor fluidly connected to the primary pump, and a fan operably connected to and driven by the motor. The circuit also includes a supply passage extending from the primary pump to the motor, a return passage extending from the motor to the primary pump, and a pressure limiting valve configured to selectively reduce pressure of a flow of pilot fluid directed to the primary pump. The circuit further includes an override valve configured to selectively connect the supply passage to the pressure limiting valve.

Abstract: Various embodiments related to hydraulic actuators and active suspension systems as well as their methods of use are described.

Abstract: A hydraulic circuit for a ram cylinder includes: a ram cylinder which drives a driven device; a hydraulic unit including (i) a supply circuit which includes a supply control valve and a supply throttle valve, and (ii) a discharge circuit which includes a discharge control valve and a discharge throttle valve; and a first supply/discharge circuit which connects the ram cylinder with the supply circuit of the hydraulic unit, and a second supply/discharge circuit which connects the ram cylinder with the discharge circuit of the hydraulic unit. A bypass circuit having an opening/closing function connects a portion downstream from the supply control valve and the supply throttle valve with a portion downstream from the discharge control valve and the discharge throttle valve, and the bypass circuit allows the first and second supply/discharge circuits to serve a plurality of functions.

Abstract: A fluid-dynamic circuit includes a source of a pressurized fluid; a distributor valve for distributing the pressurized fluid to transport lines; a feeding line for feeding the pressurized fluid, which is interposed between the source and the valve; a main user apparatus, which is reciprocatingly operated by an actuator that includes a slider sealably fitted in a sliding seat of a containing element divided thereby into a first chamber and a second chamber in opposite positions and having variable volumes; and second and third transport lines for the pressurized fluid, which are interposed between the distributor valve and the first and second chamber respectively, a first derived transport line being interposed between the valve and at least one of the second and third transport lines, and having a normally closed quick discharge device mounted thereto, whose opening is designed to be controlled by the actuator.

Abstract: A hydraulic system for an operator controlled machine, the system including at least one actuator for moving a machine component, a source of pressurized fluid for delivering pressurized fluid at a system pressure to a control valve which is operable under operator control, to control the flow of fluid from the source to the actuator at a load pressure, along a load pressure path, a flow control apparatus for controlling the flow of fluid from the source to the control valve, the flow control apparatus including an actuating part which is biased by a resilient device to a condition in which the flow control apparatus provides for a maximum flow of fluid to the control valve, actuating part movement by the resilient device being resisted by system pressure fluid and being supported by fluid at a control pressure, the control pressure being derived from the load pressure, and wherein the system includes a pressure control device to which the load pressure is communicated, the pressure control device being opera

Abstract: There is provided a circulation line (39) for circulating pressurized oil from an accumulator (11) into a housing (15) of a steering valve (14). An orifice joint (41) is provided along the path of the circulation line (39). The orifice joint (41) is removably mounted on the housing (15) of the steering valve (14) from outside. An orifice portion (42) of the orifice joint (41) applies a throttling function to the circulating oil liquid whereby a frictional heat is generated therein. The oil liquid in a warm state flows through a communication passage (21), passages in a spool valve (16), and a low pressure side passage (18B), thus enabling the steering valve (14) to be always in a warm state.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump configured to draw low-pressure fluid from one of a first and a second passage, and discharge fluid at an elevated pressure into the other of the passages. The hydraulic system may also have an actuator coupled to the pump via the first and second passages, a charge circuit, and a makeup valve movable by a pressure differential between the first and second passages to connect the charge circuit with a lower pressure one of the first and second passages. The hydraulic system may further have a first force modulation control valve configured to selectively direct fluid from the pump through the makeup valve to the second passage to bypass the actuator, and a second force modulation control valve configured to selectively direct fluid from the pump through the makeup valve to the first passage to bypass the actuator.

Abstract: A hydraulic system is disclosed having a pump configured to draw low-pressure fluid from one of a first and second passage, and discharge fluid into the other of the passages. The hydraulic system may also have an actuator coupled to the pump via the passages, a charge circuit, a makeup valve movable to pass fluid from a higher pressure one of the first and second passages, and a force modulation control valve disposed between the makeup valve and the charge circuit. The force modulation control valve may be movable between a first position at which fluid passed from the higher-pressure one of the first and second passages is directed into the charge circuit, and at least a second position at which fluid from the higher-pressure one of the first and second passages is directed into a lower-pressure one of the first and second passages and blocked from the charge circuit.

Abstract: A power generating apparatus includes a rotating shaft, a hydraulic pump driven by the rotating shaft, a hydraulic motor driven by operating oil supplied from the hydraulic pump; and a generator coupled to the hydraulic motor. The apparatus further includes an oil line connected to the hydraulic pump and the hydraulic motor for circulating the operating oil between the hydraulic pump and the hydraulic motor, an oil cooler connected to the oil line for cooling the operating oil by heat exchange with a cooling medium, a cooling-medium line supplying the cooling medium to the oil cooler; a bypass line diverging from at least one of the oil line and the cooling-medium line and merging into at least one of the oil line and the cooling-medium line to bypass the oil cooler; and a flow regulating valve in at least one of the oil line and the cooling-medium line.

Abstract: This invention consists of two or more fixed displacement hydraulic pump/motors mounted on a common input shaft hydraulically connected to two or more fixed hydraulic pump/motors mounted on a common output shaft. The relative displacements of the pump/motors are chosen such that by selectively activating the individual pump/motors, the transmission ratio can be changed in the case when the input devices and acting as pumps driving the output devices as motors (conversely when driving the vehicle in reverse). Further, a hydraulic accumulator and reservoir are attached in a manner that allows the pressurized fluid to augment the flow produce by the input pumps in order to increase the transmission ratio. Similarly, the transmission ratio can also be reduced by causing the input pumps to pump fluid into the accumulator at the same time they are pumping fluid through the output motors.

Abstract: A hydraulic system has a variable displacement pump that sends fluid from a tank into a supply conduit from which separate open-center control valves convey the fluid to each one of a plurality of hydraulic actuators. The control valves have open-center orifices connected in series between a bypass node and the tank, thereby forming a bypass passage. Pressure at the bypass node controls displacement of the pump. A valve arrangement is connected between an outlet of the pump and the bypass node and is responsive to an amount of fluid flow through the supply conduit to the plurality of hydraulic functions, wherein as the amount of fluid flow increases, the valve arrangement causes fluid flow to the bypass node to decrease. Thus the pressure at the bypass node varies as a function of the operation of the control valves.

Abstract: A hydraulic system is disclosed. The hydraulic system may have an over-center, variable-displacement pump, an actuator, and first and second passages that create a closed-loop circuit. The hydraulic system may also have first and second check valves disposed in the first and second passages, respectively, to allow flow only from the pump to the actuator. The hydraulic system may further have a first bypass line connecting the first passage at a location between the actuator and the first check valve to the first passage at a location between the first check valve and the pump, and a second bypass line connecting the second passage at a location between the actuator and the second check valve to the second passage at a location between the second check valve and the pump. The hydraulic system may additionally have a valve configured to control flow through the first and second bypass lines.

Abstract: The present invention provides a method of controlling a fluid working machine (12) having a plurality of working cylinders (14) having pistons (16) therein and arranged to drive a shaft (18), in which said cylinders are supplied with pressurized working fluid via a manifold (24), the contents of which may be 5 purged by a de-pressurizer taking one of a number for forms such as to allow re-activation of said machine (10).

Abstract: A hydraulic manifold system for lifting, installing, or repairing large industrial field equipment. The system includes a hydraulic motor, which is fluidly connected to a hydraulic line of a vehicle, which is drivingly connected to a high-pressure hydraulic pump and fluidly connected to above-ground jack, ram, or lifting device. An above-ground jack, ram, or lifting device is hydraulically actuated by the fluid supplied by the hydraulic pump wherein a remote electronic controller can be utilized to provide a signal in order to depressurize the auxiliary device using an electronically actuated valve.

Abstract: A meter includes an inlet for receiving a fluid and a housing defining a cylindrical chamber receiving the fluid from the inlet, wherein a chamber axis passes through a center of the cylindrical chamber. The meter also includes an outlet coupled to the housing, wherein the outlet is axially aligned with the inlet along a flow axis, and the flow axis does not intersect the chamber axis.

Abstract: A drive unit and a method for the operation thereof. The drive unit has an internal combustion engine in operative connection with a driven shaft and a reciprocating piston expansion engine in an operative connection with a crankshaft. The driven shaft is mechanically connected to the crankshaft by a clutch in such a way that torque is transmitted from the crankshaft to the driveshaft. The reciprocating piston expansion engine has at least one cylinder, and a fluid is guided from a fluid supply into an interior of the at least one cylinder at least occasionally via an inlet valve and a bypass valve which is arranged in parallel with the inlet valve.

Abstract: The present invention is intended to provide a technology that can utilize the advantages of both a load sensing control and a regeneration circuit without causing any problem. A regeneration circuit is added to a hydraulic circuit provided with a hydraulic pressure signal line for detecting a hydraulic pressure value of a circuit and controlling a volume of hydraulic fluid to a cylinder 1 with reference to the detected value. A pressure reducing valve 6 that outputs a reduced pressure as an operating signal to a pump 2, and subsequently the controlling means 5 causes the pressure reducing valve 6 to output a pressure reduction command to a pump 2 and thus to reduce a discharge rate from the pump 2, when the regeneration circuit is in a regeneration state.

Abstract: A hydraulic power unit is disclosed that is selectively connectable to a hydraulic tool. The hydraulic power unit automatically detects the attached or detached state of the tool and/or operates an unloading valve during activation of the tool.

Abstract: A throttle path for returning a part of pilot oil to a tank is formed by a tank path provided in a valve block of a control valve and a notch provided in a spool thereof. The above path is opened within a section from a vicinity of a stroke where a hydraulic actuator starts moving to right before a stroke end among a spool stroke of the control valve. An opening area of the above path is slowly reduced in accordance with an increase in the stroke at a final phase of the section.

Abstract: A bypass pin for a hydrostatic transmission is disclosed. The hydrostatic transmission has a hydraulic pump. The bypass pin has a head positioned at one end of a shaft. The bypass pin also has a tip positioned at an opposite end of the shaft. The bypass pin is configured to receive a linear force exerted against the head in a first direction which causes the bypass pin to move in the first direction. The shaft of the bypass pin is configured to be positioned through a casing containing the hydrostatic transmission. The tip is configured to contact a rotating member in the hydraulic pump when the rotating member is in contact with a fluid directional member, the tip pushing the rotating member away from a fluid directional member in the first direction when the linear force is applied.

Abstract: A steering system includes a fluid motor and a steering unit. The steering unit is in fluid communication with the fluid motor. The steering unit includes a fluid meter adapted to meter fluid to the fluid motor in response to actuation of the steering unit. A valve housing is in fluid communication with the fluid meter. The valve housing defines a valve bore. A valve assembly is disposed in the valve bore. The valve assembly defines a primary fluid path to the fluid meter and to the fluid motor from the fluid meter. The valve assembly further defines a secondary fluid path to the fluid motor that bypasses the fluid meter. An amount of fluid through the secondary fluid path is based on volumetric efficiency of the fluid motor.

Abstract: A power take off system for a hybrid-electric vehicle comprises an internal combustion engine, a hybrid-electric motor and generator, a power take off mechanism, a control module, and an engaging mechanism. The motor and generator couples to the internal combustion engine. The power take off mechanism couples to the internal combustion engine and the motor and generator. The power take off mechanism receives torque from at least one of the engine and the motor and generator. The control module is disposed in electrical communication with a system controller. The control module generates output signals for controlling the engine. The engaging mechanism is disposed in electrical communication with the system controller. The engaging mechanism has a first mode and a second mode. The power take off mechanism is decoupled from the engine and the motor and generator in response to an output signal generated by the system controller.

Abstract: A system for providing pressurized hydraulic fluid in a transmission of a motor vehicle includes a pump for providing pressurized hydraulic fluid having an inlet port and an outlet port. A bypass valve includes an inlet port in communication with the outlet port of the pump, a first outlet port in communication with the inlet port of the pump, and a second outlet port. The inlet port of the bypass valve is in communication with the second outlet port of the bypass valve when the bypass valve is in a first position and the inlet port of the bypass valve is in communication with the first outlet port of the bypass valve when the bypass valve is in a second position. A control device and accumulator are operatively associated with the bypass valve.

Abstract: A hydraulic manifold pump comprising a housing in which is located a first hydraulic circuit and a second hydraulic circuit. A bidirectional motor connectable to the first hydraulic circuit and the second hydraulic circuit, the bidirectional motor being able to activate the first hydraulic circuit when operable in a first direction, and being able to activate the second hydraulic circuit when operable in a second direction. The hydraulic manifold pump further compromises a hydraulic actuator having two hydraulic chambers being connectable to the first hydraulic circuit and to the second hydraulic circuit, and both the first and second hydraulic circuits being connected to and able to vent into a fluid reservoir.

Abstract: Methods and systems for operating a cylinder lock valve to control fluid flow to a hydraulic cylinder operating a drilling rig sub-system. The lock valve 1) allows fluid flow through the valve if pressure on a main and pilot area overcomes a closing spring force on the valve, or 2) blocks flow through the valve if a loss in charge pressure in the main and pilot area falls below the closing spring force on the valve.

Abstract: A work vehicle includes a hydrostatic continuously variable speed-change device, a gear type multiple-stage speed-change device disposed downstream of the hydrostatic continuously variable speed-change device with respect to a direction in which power is transmitted, first and second oil passages, a bypass oil passage communicating the first and second oil passages with each other, a valve mechanism for opening and closing the bypass oil passage, and a manual operating member provided in a driving section for opening and closing the valve mechanism.

Abstract: A work machine (10) comprises an auxiliary electro-hydraulic circuit (22) adapted to operate a hydraulic actuator (16) of an auxiliary tool (12) when the auxiliary tool (12) is attached to the work machine. The auxiliary electro-hydraulic circuit (22) is electrically controlled by a controller unit (24) in a proportional mode or a continuous mode.

Abstract: An improved anti-cavitation hydraulic manifold for hydraulically coupling the hydraulic input and output of two, drive coupled, reversible hydraulic motors and a reversible source of hydraulic power for winding and unwinding systems is described wherein a stop confines a shuttle ball within each of two input/output (I/O) chambers receiving driving hydraulic input liquid from the reversible source of hydraulic power between an annular valve seat around a bypass passage communicating between the bases of the input/output (I/O) chambers and any ports penetrating into the respective input/output (I/O) chambers supplying high pressure or driving hydraulic input from the reversible source of hydraulic power where, responsive to supplied high pressure or driving hydraulic input to a particular I/O chamber, the shuttle ball in the chamber seats upon the particular annular valve seat translating a shuttle rod in the bypass passage unseating the particular shuttle ball from the annular valve seat around the passageway

Abstract: A hydraulic circuit including a first throttle disposed upstream of pressure-reducing valves of a remote-control valve, which operates a control valve of hydraulic pilot type, so as to reduce primary pressures supplied from a pilot pump to the pressure-reducing valves. Bleed-off lines connect pilot lines to tanks. Second throttles are disposed on the bleed-off lines, respectively, so as to moderate rises in the pilot pressures supplied to pilot ports of the control valve. The hydraulic circuit prevents detrimental effects such as deterioration of operability while ensuring shock absorption during quick operation.

Abstract: A heavy-construction machine (1) including a working implement (5) having one or a number of arms (6) articulated with regard to the chassis (2) of the machine. An assembly consisting of at least one hydraulic cylinder (7) that causes the working implement (5) to move relative to the chassis (2) is provided together with a hydraulic circuit that supplies these cylinders based on the control commands issued by a hydraulic manipulator. The machine is capable of operating according to two distinct modes of which one is a lifting mode and the other is a loading mode. In each mode, cylinder travel can be freed when the manipulator is in a predetermined position corresponding to a position referred to as floating control. The machine further includes a mechanism for rendering the floating control position of the manipulator inactive when the machine is operating in lifting mode.

Abstract: A transmission device (10) having at least one form-fitting shifting element (12) which is hydraulically actuated via a hydraulic system (11) with hydraulic pressure (p—12), in the area of a piston chamber, via a feed line (20) that conveys hydraulic fluid, to shift from a disengaged to and engaged operating state. A non-return valve device (27) is arranged upstream of the form-fit shifting element (12).