Abstract: A pneumatic fastener driving tool that forces pressurized gas from a gas supply source into a chamber above a piston enclosed in a working cylinder. During an operational cycle, the pressurized gas is released, forcing the piston to fire. The firing valve seals the pressurized gas utilizing two rolling diaphragm seals, thereby providing less breakdown of hardware and removing the need for lubricant within the firing valve. These diaphragm seals exhibit a smaller diameter than prior diaphragms used in similar pneumatic fastener driving tools.

Abstract: In order to reduce oscillations in process variables of an injection molding process, an injection molding machine may be operatively connected to a model database that stores models of injection molding machines and molds. A tuning controller may set initial gain values of a variable-gain proportional-integral-derivative (PID) controller. To set the initial gains, the tuning controller may be configured to obtain, from the model database, a model for a first and second injection molding machines and a model for a mold. The tuning controller may analyze the models to determine a correlation between injection molding machine parameters and mold cycle performance for the mold. Accordingly, the tuning controller may apply the correlation to determine an initial gain value for a least one of the first, second, and third gains of the PID controller. The tuning controller may then set the initial gain values for the PID controller.

Abstract: A fastener driver includes a housing, a cylinder disposed within the housing, a piston positioned and moveable within the cylinder, a driver blade attached to the piston and moveable with the piston from a first position toward a second position during a fastener driving operation, and a nosepiece at least partially defining a fastener driving track through which fasteners are driven by the driver blade. The nosepiece includes a longitudinal guide groove in which a fastener is received, and parallel guide ribs extending from an interior surface of the nosepiece, thereby defining an extension of the guide groove. When the driver blade is in the second position, the driver blade partially overlaps with the guide ribs, thereby allowing a first portion of the fastener to be received in the guide ribs and a lower, second portion of the fastener to be received in the guide groove.

Abstract: A pneumatic actuator and control valve assembly has a housing with a control cavity for a control valve and an actuator cavity for an actuator piston and rod assembly. The control cavity and actuator cavity both have an elongated shape and are substantially parallel to each other. The control cavity has a supply port and first and second control valve outlet ports and at least one vent port with the control valve being movable through the control cavity for controlling communication between the supply port and the first and second outlet ports. The actuator cavity has first and second ports at the retracted and extended ends for shuttling the piston and within the actuator cavity between a retracted and extended end position. The housing has a first inlet and second inlet for passage of pressurized fluid to and from the housing.

Abstract: A method for actuating the movement of a boom, or an attachment, in a work vehicle includes determining a joystick position difference between the actual component of the position of the joystick along a boom, or attachment, actuation axis in a first time instant and a neutral position of the joystick along the boom, or attachment, actuation axis, determining a first position of the boom, or attachment, along the boom travel path in the first time instant, and a second position of the boom, or attachment, along the boom travel path in a second time instant, and determining a boom, or attachment, position difference between the second position and the first position. If the determined boom, or attachment, position difference is lower than a threshold and the determined joystick position difference is higher than a joystick position difference threshold, the method also includes slowing movement of the boom, or attachment.

Abstract: A fastener driver includes a housing, a cylinder disposed within the housing, a piston positioned and moveable within the cylinder, and a driver blade. The driver blade includes a body defining a first end having an aperture defined therein and a second end opposite the first end. The aperture is sized to receive a fastener to attach the driver blade to the piston. The driver blade is moveable with the piston from a first position toward a second position along a longitudinal axis during a fastener driving operation. A nosepiece at least partially defining a fastener driving track through which fasteners are driven. A total length of the fastener driver as measured between a distal end of the nosepiece and a distal end of the cylinder is less than 11.4 inches (289.6 mm).

Abstract: An air cylinder in which a flow rate controller is built in, has a head cover and a rod cover. A pilot air adjustment unit guides exhaust air to a switch valve of the flow rate controller as pilot air, and the switch valve is switched by an increase in the pressure of the pilot air.

Abstract: A regeneration device includes: a regeneration valve that controls the flow rate of an operating fluid being drained from one port of a cylinder; a non-return valve that allows a regenerative flow of the operating fluid from the regeneration valve to the other port of the cylinder and blocks an opposite flow of the operating fluid; and an exhaust valve that controls the flow rate of the operating fluid output from the regeneration valve being drained to a tank. The regeneration valve controls the flow rate independently of the exhaust valve.

Abstract: A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

Abstract: A fastener driver includes a housing, a cylinder disposed within the housing, and a piston positioned and moveable within the cylinder. The fastener driver additionally includes a nosepiece at least partially defining a fastener driving track through which fasteners are driven, and a driver blade attached to the piston and moveable with the piston to drive the fasteners through the fastener driving track. The driver blade includes an axial guiding projection for guiding the driver blade within the nosepiece, and wherein the projection terminates before a distal end of the driver blade.

Abstract: A pneumatic tool includes a drive part configured to be driven by compressed air, a control valve configured to switch the presence or absence of operation of the drive part, and a timer part configured to switch the presence or absence of operation of the control valve after a lapse of a predetermined time. The timer part includes a timer piston configured to move in one direction, a timer piston cylinder configured to support the timer piston such that the timer piston can slide, and an on-off valve part configured to switch the presence or absence of operation of the control valve in conjunction with the timer piston. The on-off valve part includes a shaft portion configured to move in conjunction with the timer piston, and compressed air flowing into the on-off valve part presses the shaft portion in the one direction.

Abstract: A pneumatic fastener driving tool that forces pressurized gas from a gas supply source into a chamber above a piston enclosed in a working cylinder. During an operational cycle, the pressurized gas is released, forcing the piston to fire. The firing valve seals the pressurized gas utilizing two rolling diaphragm seals, thereby providing less breakdown of hardware and removing the need for lubricant within the firing valve. These diaphragm seals exhibit a smaller diameter than prior diaphragms used in similar pneumatic fastener driving tools.

Abstract: The present disclosure relates to a blended or hybrid power system with increased operating efficiency. The blended power system combines the advantages of electrical power with the advantages of hydraulic power when delivering power to a hydraulic actuator. The hydraulic power provides higher power density and the electrical power provides high efficiency and control accuracy in the blended power system. In a blended power system, a control system may be configured to select different modes of operation based on the loads encountered in the combined hydraulic and electrohydrostatic system. The blended power system also allows for smooth and uninterrupted transitions between the different modes of operation within the blended power system. Thus, jerkiness in the blended power system may be minimized or eliminated.

Abstract: A pneumatic tool includes a drive part configured to be driven by compressed air, a control valve configured to switch the presence or absence of operation of the drive part, an on-off valve part configured to switch the presence or absence of operation of the control valve, and a timer part configured to control the operation of the on-off valve part and switch the presence or absence of operation of the control valve after a lapse of a predetermined time. The timer part comprises a timer piston configured to move in one direction and perform timekeeping, and a timer piston housing configured to support a shaft of the timer piston. The timer piston housing is provided with a groove on a guide surface of the shaft of the timer piston, the groove being configured to expand a flow path formed between the shaft and the guide surface.

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

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

Abstract: A rotating head assembly includes a body, an implement, a clamp assembly, a drive member, a hydraulic motor, and a bypass circuit. The drive member is threadingly connected to a first clamp member and a second clamp member. The hydraulic motor is connected to the drive member to cause the drive member to rotate in a selected direction. An inlet of the bypass circuit is in fluid communication with an inlet of the hydraulic motor to receive a portion of the pressurized hydraulic fluid passing to the hydraulic motor. An outlet of the bypass circuit is in fluid communication with the outlet of the hydraulic motor. At least one bypass valve is interposed between the inlet of the bypass circuit and the outlet of the bypass circuit. The bypass valve has an actuator positioned adjacent one of the first clamp member and the second clamp.

Abstract: An excavator includes a hydraulic oil holding circuit that is provided in an oil passage between a bottom-side oil chamber of a boom cylinder and a control valve and is closed when the boom is not lowered, and a controller. The controller releases a closed state of the hydraulic oil holding circuit when the excavator is in a predetermined unstable state, and controls a released state so that an acting velocity in a lowering direction of the boom becomes less than or equal to a predetermined reference.

Abstract: To provide a work machine that makes it possible to drive actuators faster and more accurately by supplying flows to the actuators accurately at target rates without depending on load variations in a case where the machine body is controlled automatically by command inputs of a controller, while high operability is ensured for manual operation by an operator. In a case where a machine control function is cancelled via a machine control switch, a controller cancels limitation of the flow rate of a hydraulic fluid supplied to a plurality of directional control valves, the limitation being performed by the auxiliary flow rate control devices, and in a case where the machine control function is selected via the machine control switch, the controller causes the auxiliary flow rate control devices to limit the flow rate of the hydraulic fluid supplied to the plurality of directional control valves.

Abstract: A shovel includes a traveling undercarriage, an upper turning structure, an attachment, an end attachment position detecting device, an object detecting device, and a processor. The upper turning structure is turnably mounted on the traveling undercarriage. The attachment is attached to the upper turning structure, and includes an end attachment at an end thereof. The end attachment position detecting device is configured to detect the position of the end attachment. The object detecting device is configured to detect the position of an object. The processor is configured to control the movement of at least one of the attachment and the upper turning structure, based on the relative positional relationship between the excavation completion position of the end attachment and the position of the object.

Abstract: There is provided a work machine that can limit operation of a work device by MC, and improves the responsiveness of a hydraulic actuator to operation of an operation device by an operator, and ensures operability equivalent to that of a work machine that does not have MC functions, and allows the hydraulic actuator for which the operation device is not being operated to automatically operate in either direction of the operation directions thereof. For this purpose, a drive system includes a selector valve 203a disposed between a secondary port 134a of an operation device 45a and a flow control valve 15a and between a proportional solenoid valve 54a and the flow control valve 15a and a selector valve 203b disposed between a secondary port 134b of the operation device 45a and the flow control valve 15a and between a proportional solenoid valve 54b and the flow control valve 15a.

Abstract: An electrohydraulic poppet valve device control system includes a main body, an extend poppet valve, a retract valve body, a retract poppet valve, and an actuator. The actuator is movable to an extend position, a retract position, and a null position, and moves to, or remains in, the null position when electrical power is not supplied to the actuator. In the extend position, the extend poppet valve is in its open position and the retract poppet valve is in its closed position. In the retract position, the extend poppet valve is in its closed position and the retract poppet valve is in its open position. In the null position, the extend poppet valve is in its closed position and the retract poppet valve is in its closed position.

Abstract: A pneumatic or hydraulic mechanism has a housing defining a piston chamber and having a fluid inlet port. A piston is slidable in the piston chamber. The piston partitions the piston chamber into a front chamber and a rear chamber. The piston has one or more passages for fluid communication between the rear chamber and the front chamber, the one or more passages being sealed by a sealing mechanism. The sealing mechanism has a sealing state in which the sealing mechanism substantially inhibits fluid communication between the rear chamber and the front chamber, and a non-sealing state in which the sealing mechanism allows fluid communication between the rear chamber and the front chamber. The piston is slidable between a first position and a second position. When the piston is positioned in the first position, the sealing mechanism is in the sealing state.

Abstract: To provide a driver that can be reduced in the amount of gas to be injected into a pressure chamber. The driver has: an impactor configured to hit a stopper by moving from a first position toward a second position; a pressure chamber to be filled with gas for moving the impactor from the first position toward the second position; a control mechanism configured to move the impactor from the second position toward the first position; and a gas injection portion configured to inject gas into the pressure chamber, wherein the impactor is capable of taking a standby position between the second position and the first position, and the control mechanism is configured to stop the impactor at an adjustment position closer to the second position than the standby position before gas is injected into the pressure chamber.

Abstract: A work machine management apparatus includes: a working element identification information acquiring unit acquiring working element identification information indicating replacement of a working element; a flow rate setpoint acquiring unit acquiring a flow rate setpoint of a hydraulic oil for the working element; a pressure setpoint acquiring unit acquiring a pressure setpoint of the hydraulic oil for the working element; a working element operation information acquiring unit acquiring the acquired flow rate setpoint, the acquired pressure setpoint and operation information of the working element; and a working element actual operation information calculator calculating actual operation information containing an actual operation duration of the working element based on the information acquired by each of the working element identification information acquiring unit, the flow rate setpoint acquiring unit, the pressure setpoint acquiring unit and the working element operation information acquiring unit.

Abstract: A system provides regulated delivery of a high-pressure gas. A first flow path, coupled to a high-pressure gas source, is in fluid communication with a chamber. A flow restrictor, disposed in the first flow path, slows the gas traveling along the first flow path to the chamber. A second flow path, coupled to the high-pressure gas source, is in fluid communication with the chamber. A third flow path connects the chamber to a pressure regulator. A valve, disposed in the second flow path, seals the second flow path when gas pressure at the source exceeds gas pressure in the chamber. The valve opens the second flow path when the gas pressure at the source is balanced with the gas pressure in the chamber allowing the high-pressure gas to flow to the regulator via the third flow path.

Abstract: A lock valve including a poppet valve element which is disposed within a spring chamber, a spring which biases the poppet valve element leftward, and a valve seat which comes into contact with the poppet valve element is disposed in a cavity formed in a valve body to mount a relief valve therein and is positioned further inward than the sleeve of the relief valve. The outer peripheral portion of the poppet valve element has hole portions formed therein at regular intervals. The outer peripheral portion of the valve seat, too, has hole portions formed therein at regular intervals. The valve portion of a solenoid valve is disposed between a passage which is in communication with the spring chamber and a passage which is in communication with a second flow passage open to a low-pressure region such as a hydraulic tank.

Abstract: A hydraulic regulating device includes a continuously adjustable regulating valve with a control piston. The control piston is displaceable in a first direction in which a connection of a pump port to an actuating-pressure port is configured to be controlled to open. The control piston is also displaceable in a second direction in which a connection of the actuating-pressure port to a tank port is configured to be controlled to open. In the first direction, the pump pressure acts on the control piston, and in the second direction, a control pressure and a spring act on the control piston. During movement of the control piston in the first direction, a damping connection, equipped with a damping nozzle, from the pump port to the tank port is configured to be controlled to open.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a tank configured to hold a supply of fluid, a pump configured to draw fluid from the tank and pressurize the fluid, a first cylinder operatively connected between a first side of a work tool and an undercarriage of the machine, and a second cylinder operatively connected between a second side of the work tool and the undercarriage of the machine. The hydraulic system may also have a first electro-hydraulic valve associated with the first cylinder and configured to selectively regulate a flow of pressurized fluid to the first cylinder independently of the second cylinder, and a second electro-hydraulic valve associated with the second cylinder and configured to selectively regulate a flow of pressurized fluid to the second cylinder independently of the first cylinder.

Abstract: A hydraulic system for a loader backhoe work machine in which a propulsion system has a limited output and the pressure relief for the hydraulic actuation system is at a first level for the loader function in which the machine is moved on the ground and a second higher pressure relief for when the backhoe function is being performed.

Abstract: Provided is a hydraulic system for a work machine, which can ensure low temperature responsiveness of remote control valves that perform pilot operations of pilot operated directional control valves for controlling hydraulic actuators, respectively. In order to, with bringing an unloading valve V13 to an unloading position 29, circulate oil to a pilot pump oil passage w that supplies the pressure oil from the discharging circuit Y for a pilot pump 19 to remote control valves PV1, PV2, and PV6, a warm-up circuit H that flows the oil from the discharging circuit Y for the pilot pump 19 to a terminal of the pilot pump oil passage w is provided.

Abstract: A switch valve which is configured such that a plurality of land sections and a valley section between the land sections are formed in a valve element that advances or retreats in an axial direction according to a manual operation, a plurality of port sections opened are provided in a cylinder section in which the valve element is inserted so as to be capable of advancing and retreating, and the prescribed port sections are made to communicate with each other via the valley section according to a position of the valve element in the axial direction or be blocked by the land section, the switch valve includes a seal section that seals a space between portions on both sides in the axial direction across either one of the land sections in a liquid-tight manner.

Abstract: A gas turbine engine control system according to an exemplary aspect of the present disclosure includes, among other things, an automatic control operable to control a gas turbine engine. The gas turbine engine control system further comprises a module operable to fail-fix the gas turbine engine to one of a multiple of pre-determined modes in response to failure of the automatic control. The exemplary gas turbine engine control system may further comprise a fuel flow meter to sense a fuel flow to the engine, a fuel control to control the fuel flow to the engine, and the module in electrical communication with the fuel flow meter to fix the fuel control in response to one of the multiple of pre-determined modes.

Abstract: A work vehicle includes an engine, an idling stop execution portion, a determination portion, a counting portion, and an idling stop time period adjustment portion. The engine can rotate in a first idling state and a second idling state in which the engine rotates at the number of rotations higher than a prescribed number of rotations. The idling stop execution portion performs an idling stop operation for stopping the engine. The determination portion determines whether or not stop has been made from the second idling state. The counting portion counts the number of times of stop of the engine from the second idling state. An idling stop time period adjustment portion makes a prescribed time period of the second idling state longer than a current time period, when the number of times of stop of the engine is equal to or greater than the prescribed number of times.

Abstract: A hydraulic pilot control arrangement for a spool valve is provided, wherein the spool of the spool valve is biased towards a central position. The arrangement includes a first and a second pilot hydraulic line connected to opposite sides of the spool of the spool valve and a pilot pressure regulating arrangement is provided for selectively establishing or removing a pilot pressure in each of the first and second lines. The arrangement includes a damping device including a chamber divided into a first and a second pressure compartment by a sliding piston, the first and second pressure compartments being connected respectively to the first and second pilot hydraulic lines, and the piston is biased towards a rest position in the chamber.

Abstract: A universal heat engine is disclosed for converting energy from an input heat source to an output. The universal heat engine comprises a heat engine section and an output section. The heat engine section includes a heat engine bore receiving a heat engine piston. A heat engine valve assembly communicates with the heat engine bore for effecting reciprocal motion of the heat engine piston. The output section includes an output bore receiving an output piston. A piston rod interconnects the heat engine piston to the output piston. A control controls the heat engine valve assemblies to operate the heat engine section in accordance with a desired output from the output section. The heat source may comprise the burning of a petroleum product, a solar heat source, geothermal heat source or a byproduct heat source. The output may comprise a static or mobile air conditioning system or an electrical generator.

Abstract: A control device for a hybrid construction machine includes a discharge pressure introduction passage that leads a discharge pressure from a variable volume pump to a regulator, and a load pressure introduction passage that leads one of a maximum load pressure of respective actuators and a load pressure of a hydraulic motor to the regulator. A controller, having determined that the actuators are in an inoperative condition on the basis of a detection result from an operating condition detector, excites a solenoid of a solenoid pilot control valve such that a discharge oil from the variable volume pump is led to the hydraulic motor, and controls the regulator such that a differential pressure between the discharge pressure of the variable volume pump and the load pressure of the hydraulic motor is kept constant.

Abstract: A lock valve switching section switches a lock valve from a locked state to a released state when a lock member is switched from a locked position to a release position. An erroneous operation monitoring section maintains the lock valve in the released state when the pilot pressure is equal to or more than a predetermined pressure when elapsed time, which is from a point in time where the lock member is switched from the locked position to the release position, is equal to or more than the predetermined time. The erroneous operation monitoring section switches the lock valve to the locked state when the pilot pressure is equal to or more than the predetermined pressure when the elapsed time is less than the predetermined time.

Abstract: A hydraulic transmission unit comprises at least one pressure regulation valve (1) and a pilot control valve (2) which is connected to the pressure regulation valve (1) by a pilot control line (35). A pre-filling valve (3, 303) sets a pre-filling pressure (p—3) to avoid draining of a clutch (20) and the lines (231, 331) connected to the clutch (20) in an operating condition in which the clutch (20) is not actuated. To avoid draining when the clutch when in the operating condition, the pilot control line (35) is also connected to at least one line (236, 238, 336, 338) which is pressurized with a second pre-filling pressure (p—3).

Abstract: The present invention relates to a hydraulic control system for construction machinery capable of variably adjusting a set pressure of a relief valve, which controls a set pressure of a hydraulic system, according to a value inputted by means of pressure in the hydraulic system or the manipulation of a joystick.

Abstract: A poppet valve assembly includes a body having a first axial end portion and a second axial end portion. The first axial end portion includes a tapered surface adapted for sealing engagement with a valve seat. The second axial end portion defines a metering orifice. The body defines a passage that includes an opening in the first axial end portion and is in fluid communication with the metering orifice. The passage includes a check valve seat. A check valve is disposed in the passage. The check valve is adapted to sealingly engage the check valve seat.

Abstract: The present disclosure provides a hitch suspension system that reduces a transfer of energy (e.g., provides a smoother ride) between two bodies hitched together, such as between a towing vehicle and a towed vehicle/trailer. In an embodiment, the suspension system includes a hydraulic cylinder with an extendable rod in fluid communication with a fluid pump. A control valve is fluidly coupled between the hydraulic cylinder and the fluid pump and is configured to adjust an extension length of the rod. Additionally, a variable orifice that adjusts resistance to extension and retraction of the rod is fluidly coupled between the hydraulic cylinder and the control valve. A first fixed restrictive element is fluidly coupled in series with the variable orifice to dissipate energy ad the rod extends and a second fixed restrictive element is fluidly coupled in series with the variable orifice to dissipate energy as the rod retracts.

Abstract: A hydraulic circuit for operating a tool is provided that is particularly useful in construction equipment such as an excavator, crane, wheel loader, drilling machine, or others. Furthermore, a control unit and a method for controlling the hydraulic circuit and construction equipment including such a hydraulic circuit is disclosed.

Abstract: The pressure in the downstream side of a pneumatic cylinder's piston (1g) is allowed to exhaust. At a certain point, the downstream exhaust is blocked, causing the pressure to rise against the downstream side of the piston. A valve (5) opens when the downstream chamber has reached its maximum pressure. The output of valve (5) opens a second valve (3). Valve (3) rapidly exhausts the remaining air on the downstream side of the piston (1p). With no air on the downstream side of piston (1p), piston (1p) stops and does not bounce back. Changing the volume of inactive regions (1m) or (1n) sets the stopping point to coincide with the end of stroke of piston (1p). A check valve (4) and orifice (6a) allow the air in the pilot port in valve (3) to slowly bleed out, resetting valve (3) for the next cycle.

Abstract: A hydraulic system for construction equipment having a float function is provided. The hydraulic system can perform ground leveling as making a boom descend due to its own weight without using hydraulic fluid that is discharged from a hydraulic pump. The hydraulic system includes a holding logic poppet mounted in the float valve to prevent an abrupt descending of the boom due to leakage of the hydraulic fluid through a flow path between the main control valve and the float valve during the operation of the boom cylinders.

Abstract: An actuator system (14) comprising a valve assembly (40) having an inner spool (50), an outer spool (60), and a sleeve (70). An assembly (80) directly drives the inner spool (50) to move it relative to the outer spool (60), and thereby hydromechanically causes the outer spool (60) to move relative to the sleeve (70). A control assembly (90) provides current input to the drive assembly (80), which converts current input into mechanical motion. The control assembly (90) senses the position of the inner spool (50) and regulates current in accordance with the sensed position.

Abstract: A system and method for operating a two-stage, high-pressure pumping system includes a low-pressure pump having an output configured to deliver a hydraulic fluid under a low-pressure at a high-volume to drive a tool associated with the two-stage, high-pressure, pumping system under low load conditions. The system also includes a high-pressure pump having an output configured to deliver the hydraulic fluid under a high-pressure at a low-volume to drive the tool under high load conditions. A pilot-operated device is included that is configured to selectively drive the tool with pressure from at least one of the output of the low-pressure pump and the output of the high-pressure pump. The pilot-operated device receives pilot pressure from the output of the low-pressure pump to control selectively driving the tool with the output of the two stage pump.

Abstract: A holding control valve of the present invention is configured such that: a spool is configured to perform strokes by a piston configured to operate by introduction of pilot pressure and have a larger diameter than the spool; the piston is divided into a pilot piston configured to receive the pilot pressure and a relief operation piston disposed adjacent to the spool to receive pressure of relief oil discharged when a relief valve operates; and the relief oil is introduced to between the pilot piston and the relief operation piston.

Abstract: A system for controlling motion of a hydraulic actuator on a refuse collection vehicle. The system includes an operator input device configured to produce a proportional electrical signal that is proportional to the degree of motion of the operator input device. The system further includes a proportional pneumatic control valve that is configured to produce a pressurized air control signal in proportion to the proportional electrical signal, and a hydraulic control valve that is configured to selectively control flow of hydraulic fluid to a hydraulic actuator in response to the pressurized air control signal.

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.