Abstract: A roadway conduit system includes a roadway conduit section that includes a floor portion with roadway surface configured to receive traveling vehicles, a ceiling portion, and at least one sidewall portion coupled to the floor portion and the ceiling portion such that the floor, ceiling, and at least one sidewall portions define a roadway conduit volume through which the traveling vehicles traverse the roadway conduit section. The roadway conduit section includes at least two fixedly connected preformed segments. The roadway conduit system also includes a roadway conduit ingress coupled to a first location of the roadway conduit section; a roadway conduit egress coupled to a second location of the roadway conduit section; and at least one air mover configured to circulate an airflow in the roadway conduit volume in a direction of at least one of the traveling vehicles.

Abstract: This hydraulic drive system includes: first and second circuit systems; first and second hydraulic pumps; a merge valve that opens and closes a merge passage connecting the hydraulic pumps; an operation device that outputs an operation command corresponding to an amount of operation specifying an amount of actuation of first and second hydraulic actuators; and a control device that controls the merge valve according to the operation command from the operation device. The first circuit system includes: a first meter-in control valve that controls a meter-in flow rate of the working fluid that flows to the first hydraulic actuator; and a first meter-out control valve that controls a meter-out flow rate of the working fluid that is drained from the first hydraulic actuator into a tank. The control device controls an opening degree of the first meter-in control valve and an opening degree of the first meter-out control valve.

Abstract: A pump stage assembly for supplying lubricating oil, comprising: at least two pump suction stages and at least one pump pressure stage. The pump suction stages and the pump pressure stage are spaced apart from one another in a pump housing PG and have a common drive shaft. The pump suction stages are formed by a first assembly of at least three intermeshing external gearwheels and wherein the pump pressure stage is formed by a second assembly of two intermeshing external gearwheels. Here at least two respective tooth center points of the first external gearwheel assembly and the respective tooth center points of the second external gearwheel assembly are arranged in a common plane E-E which intersects the pump housing PG in a longitudinal direction.

Abstract: A modular configurable automotive lift (10) comprising: at least two automotive lift modules (100) wherein each automotive lift module comprises: an outer longitudinal post (110) having a hollow interior, an outer longitudinal post first end (111), and an outer longitudinal post second end (112) opposite the outer longitudinal post first end; an inner longitudinal post (120) at least partially nested within the hollow interior of the outer longitudinal post the inner longitudinal post having an inner longitudinal post first end (121) and an inner longitudinal post second end (122) opposite the inner longitudinal post first end; a first bearing (115) connected to an inner longitudinal surface of the outer longitudinal post; a second bearing (125) connected to an outer longitudinal surface of the inner longitudinal post; an actuator (500) configured to advance the outer longitudinal post first end away from the inner longitudinal post first end or configured to advance the inner longitudinal post first end away

Abstract: To enable to arbitrarily change a hydraulic pump which supplies pressure oil to a hydraulic actuator at first in a hydraulic control system equipped with the hydraulic actuator using both first and second hydraulic pumps as a pressure oil source. An operation means is installed which can arbitrarily change working order of the first flow rate control valves for boom and stick for controlling the supply flow rate from first hydraulic pump to boom cylinder and stick cylinder and second flow rate control valves for boom and stick for controlling the supply flow rate from second hydraulic pump to boom cylinder and stick cylinder.

Abstract: A transport vehicle is driven by a hydraulic closed circuit system having a variable displacement pump to send an operating fluid to a delivery branch and receive the operating fluid from a return branch, a plurality of hydraulic motors connected to the delivery branch and to the return branch in order to drive relative wheels of the vehicle, a command and control unit to control the pump and the hydraulic motors in an ordinary advancing condition of the vehicle and command and control unit, which is configured to intervene in case of faults or malfunctions of the pump and to control a valve so as to establish a connection between the delivery branch and the return branch regardless of the control of the command and control unit of the pump and of the hydraulic motors.

Abstract: The present invention relates to a self-propelled ground milling machine and a method for operating a ground milling machine in an emergency mode of operation.

Abstract: The invention of the present application intends to provide a work machine that can ensure high operability by preventing abrupt actuation of an actuator and a shock to a machine body by use of a bleed-off function at the time of starting of the actuator and that can improve the energy-saving performance by reducing a bleed-off flow rate after the starting of the actuator. For this purpose, a controller opens a bleed-off valve at a timing at which an operation device is being operated and before a flow rate of a hydraulic pump starts increasing, and closes the bleed-off valve at a timing at which the operation device is being operated and after the flow rate of the hydraulic pump has started increasing.

Abstract: A zero turn vehicle is disclosed, having an operator platform located adjacent to the rear of the frame. An upright riser is disposed on the frame. The vehicle uses first and second electric drive transmissions to drive the output wheels. An electrical bus or controllers may be mounted on a panel of the upright riser or on the drive transmissions to assist in providing a compact design. A pair of drive levers is mounted on the upright riser for controlling the output of the vehicle.

Abstract: A hydraulic excavator drive system includes: a first pump connected to a head-side chamber of a boom cylinder; and a second pump that supplies hydraulic oil to at least one of an arm cylinder or a bucket cylinder. The first pump is driven by an electric motor. The drive system further includes: a first switching valve located on a rod-side line; and a second switching valve located on a relay line. The first switching valve opens the rod-side line at a boom raising operation, but blocks the rod-side line except at the boom raising operation. The second switching valve blocks the relay line at the boom raising operation, but opens the relay line at a vehicle body lifting operation.

Abstract: A device including a reservoir configured to receive a lubricant from a machine lubricated with the lubricant. The device also includes a pressure equalizer connected to the reservoir. The device also includes a first loop comprising a first line system through which the lubricant flows between the machine and the reservoir. The lubricant within the first loop is at a first pressure. The device also includes a temperature regulation system configured to regulate a temperature of the lubricant. The device also includes a second loop comprising a second line system through which the lubricant flows between the temperature regulation system and the reservoir. The lubricant within the second loop is at a second pressure that is less than the first pressure. The second loop is separate from the first loop.

Abstract: A hydraulic excavator is provided which can suppress the fuel consumption amount and improve the work efficiency by reducing the hydraulic pressure loss generated when a plurality of hydraulic actuators different in load are operated simultaneously.

Abstract: A centrifuge apparatus includes a plurality of modules, each including a rotatable body, housing and flying leads, assembly. The modules can be selectively interconnected to allow adaptation of the processing capacity of the apparatus to process a liquid to remove components therefrom and/or to process a number of different liquids and allow the separation of one or more types of components therefrom simultaneously.

Abstract: A hydraulic system for a working vehicle includes a first hydraulic pump to deliver pilot fluid to a control valve for a hydraulic actuator whose highest load pressure acts on a first fluid passage, and a second hydraulic pump to deliver hydraulic fluid whose pressure acts on a second fluid passage. A hydraulic controller is operable to control a load-sensing (LS) differential pressure between the highest load pressure and a delivery pressure of the hydraulic fluid from the second hydraulic pump. A third fluid passage to which the second hydraulic pump delivers the hydraulic fluid branches to a fourth fluid passage for flow of the pilot fluid. A solenoid valve is operable to change a pilot pressure of the pilot fluid for the hydraulic controller, and a controller is configured or programmed to control the solenoid valve to adjust the pilot pressure to change the LS differential pressure.

Abstract: A modular configurable automotive lift (10) comprising: at least two automotive lift modules (100) wherein each automotive lift module comprises: an outer longitudinal post (110) having a hollow interior, an outer longitudinal post first end (111), and an outer longitudinal post second end (112) opposite the outer longitudinal post first end; an inner longitudinal post (120) at least partially nested within the hollow interior of the outer longitudinal post said inner longitudinal post having an inner longitudinal post first end (121) and an inner longitudinal post second end (122) opposite the inner longitudinal post first end; a first bearing (115) connected to an inner longitudinal surface of the outer longitudinal post; a second bearing (125) connected to an outer longitudinal surface of the inner longitudinal post; an actuator (500) configured to advance the outer longitudinal post first end away from the inner longitudinal post first end or configured to advance the inner longitudinal post first end awa

Abstract: A hydraulic arrangement for a vehicle transmission includes a hydraulic system path leading to a hydraulic system circuit with a system pressure, a hydraulic lubrication path leading to a hydraulic lubrication circuit with a lubrication pressure, and a branching point connected to an output side of the system and lubrication paths. A variable displacement pump or a pump combination includes at least two fixed displacement pumps hydraulically connected to an input side of the branching point, and a variable displacement pump or at least one fixed displacement pump are hydraulically connected to the output side of the branching point and integrated into the hydraulic system path.

Abstract: To make it possible to control supply, discharge, and recycled flow rates independently of each other for the boom cylinder in a construction machine comprising first and second boom spool valves respectively connected to first and second hydraulic pumps. When the boom cylinder is contracted, the first boom spool valve is configured to control the recycled flow rate from head side oil chamber to rod side oil chamber, the second boom spool valve is configured to control the discharge flow rate from head side oil chamber to oil tank, and both first and second boom spool valves are configured not to supply pressure oil from first and second hydraulic pumps to the boom cylinder.

Abstract: A hydraulic driving device of a suction car includes a HST circuit, a suction actuator, a supply channel and a switching valve. In the HST circuit, a first connection channel and a second connection channel connect between a traveling drive pump and a traveling motor in a closed circuit. The suction actuator suction drives a suction device by being actuated by a hydraulic pressure. The switching valve allows oil discharged from the traveling drive pump to the first connection channel to be supplied to the traveling motor in a first operation state. The switching valve allows oil discharged from the traveling drive pump to the first connection channel to flow into the supply channel and be supplied to the suction actuator in a second operation state.

Abstract: A hydraulic system having a hydraulic pump, having a plurality of hydraulic loads and having a plurality of load-sensing valves for adjusting the pump performance of the hydraulic pump. An association unit is arranged between the hydraulic pump and the hydraulic loads and in a first switched state defines a first hydraulic path between the hydraulic pump and the hydraulic loads and in a second switched state defines a second hydraulic path between the hydraulic pump and the hydraulic loads. The system comprises a controller, which processes a state value of a hydraulic load as an input variable and which determines a control signal for the switched state of the association unit. The invention also relates to a method for controlling a hydraulic system.

Abstract: A working fluid supply device is provided with: a first oil pump and a second oil pump driven by an engine; a third oil pump driven by an electric motor; a first unloading valve configured to shift the second oil pump to a no-load operation state; and a controller configured to control a supply state of working oil to an automatic transmission. The controller sets the supply state to a supply state selected from: a first supply state in which the working oil is supplied only from the first oil pump; a second supply state in which the working oil is supplied from the first oil pump and the third oil pump; a third supply state in which the working oil is supplied from the first oil pump and the second oil pump; and a fourth supply state in which the working oil is supplied from the first oil pump, the second oil pump, and the third oil pump.

Abstract: A hydrostatic transmission assembly includes a first housing member and a housing cap sealed to the first housing member to form a sump wherein a pump and motor are rotatably disposed. A pump mount is located in the sump and engaged to the housing cap. The housing cap also includes a motor mount for an axial piston motor, and hydraulic fluid passages for connecting the pump to the motor. A pocket is located in the housing cap to rotationally support a swash plate for the pump.

Abstract: An electric vehicle supply equipment includes multiple first power modules and a control circuit. The first power modules are electrically coupled in series at output and configured to provide a charging current and a charging voltage to charge an electric vehicle. The control circuit is configured to control one of the first power modules to be operated in a constant current mode to output the charging current, and configured to control the rest of first power modules to be operated in a constant voltage mode respectively to have at least one output voltage for generation of the charging voltage.

Abstract: In a method of controlling a main control valve of an excavator, when speeds of a boom cylinder and an arm cylinder is increased by handling a boom joystick and an arm joystick, a second arm control spool between a first hydraulic pump and the arm cylinder may be closed. A first boom control spool between the first hydraulic pump and the boom cylinder may be opened to supply a first flux generated from the first hydraulic pump to the boom cylinder. A second boom control spool between a second hydraulic pump and the boom cylinder may be closed. A first arm control spool between the second hydraulic pump and the arm cylinder may be opened to supply a second flux generated from the second hydraulic pump to the arm cylinder.

Abstract: The invention relates to a control method for a quick change device of a work tool, comprising the steps of: receiving a command to disengage a work tool clamping device; determining whether the work tool clamping device is in an engaged state; detecting functionality of a disengagement alarm if the work tool is in the engaged state; switching to an emergency state upon the detection of failure of the disengagement alarm. The present invention further relates to a corresponding control apparatus and work machine.

Abstract: A mixer drum driving apparatus includes an auxiliary fluid pressure pump that is provided independently of a fluid pressure pump and is capable of supplying a working fluid to a fluid pressure motor so as to cause a mixer drum to perform agitation rotation, a plurality of motors configured to drive the auxiliary fluid pressure pump to rotate, and a control unit that controls rotation of the mixer drum. When an engine is stopped during the agitation rotation of the mixer drum, the control unit drives the auxiliary fluid pressure pump to rotate by operating the plurality of motors selectively in accordance with a load of the mixer drum.

Abstract: In a lowering operation of a boom, the amount of operation of a control lever is detected by a pressure sensor and input to a controller. Based on the input operation amount, the controller obtains a target flow rate Q0 of return oil discharged from a boom cylinder, calculates a deviation ?Q between the target flow rate Q0 and an actual flow rate Q obtained from an actual rotation speed N of an electric motor acquired by a rotation speed sensor, calculates a signal Sm for controlling the opening area of a proportional solenoid valve in a manner allowing hydraulic fluid to flow to a control valve in just as much as ?Q, and controls an operation pilot pressure of the control valve supplied from a sub-pump in accordance with the signal Sm so that the hydraulic fluid will flow to the control valve exactly in the amount of ?Q.

Abstract: A power distribution assembly integrated into the lower engine housing of an internal combustion engine, the assembly having a drive train with a T-box output configuration and power take off driven by the crankshaft of the engine. The drive train may power the input shafts of a pair of independent, variable drive transmissions. In one embodiment, a single actuator engages a manual clutch/brake mechanism that controls the output shaft of the power take off. In other embodiments, an electric clutch affords control of the power take off mechanism. In further embodiments, a hydraulic clutch/brake assembly allows control of the power take off, and an additional hydraulic clutch assembly may be used to control the outputs of the T-box.

Abstract: In open-circuit hydraulic systems (1), the cross-sections of the supply lines (6) and input valves of the hydraulic pump (3) have to be large, so that sufficient flow flux can be provided. This hinders a reduction of the size of the pump and the whole hydraulic system. It is suggested that the supply flow (7) of a hydraulic pump (3) is charged by a second, charging pump (2), to a mid-pressure level (7). The cross-sections of the supply flow areas can thus be decreased.

Abstract: A construction machine includes a hydraulic actuator circuit including: a first circuit connected to one of travel motors and a boom cylinder; a second circuit connected to the other travel motor and arm cylinder; and a third circuit connected to a slewing motor; control valves for hydraulic actuators; and a merging valve having a first position for unloading hydraulic fluid discharged from a third pump upon no operation except for two travel motors; a second position for merging the hydraulic fluid into the first and second circuits upon a simultaneous operation of the travel motors and an operation of at least one remaining hydraulic actuator except for a boom raising operation; and a third position for merging the hydraulic fluid into the first circuit while blocking it from the second circuit upon the boom raising operation.

Abstract: A valve actuator control system for use with a valve actuator may include two pump assemblies, two control valve assemblies, two transducers, a fluid reservoir, and a controller assembly. The controller assembly may actuate the pump assemblies to direct fluid from the fluid reservoir to the valve actuator, and may actuate the control valve assemblies to direct fluid from the valve actuator to the fluid reservoir. A method of actuating a valve actuator using a valve actuator control system may comprise sending a signal to the valve actuator control system, injecting pressurized fluid from a fluid reservoir of the valve actuator control system into a first chamber of the valve actuator, discharging pressurized fluid from a second chamber of the valve actuator into the fluid reservoir, and actuating the valve actuator from a first position to a second position.

Abstract: This invention consists of the addition of a novel clutch arrangement which facilitates speed changing gears on both the output and input of the transmission and provides for a compact packaging configuration for a plurality of hydraulic pump/motors. The use of a small accumulator without a valve and a related reservoir absorbs the pressure shocks from rapidly opening and closing the valves that that select or de-select the pump/motors. It is also disclosed that two adjacent pump/motors on the same shaft can be constructed such that they share an input or output port thereby reducing the size of the combination. The transmission can perform the retarder function by placing a flow retarding valve in the re-circulating path in one or more of the pump/motors.

Abstract: Provided is a hydraulic engine that generates power using oil pressure, the hydraulic engine including: a hydraulic power unit including a hydraulic tube comprising a hollow portion having an opened front end and being filled with a fluid, an amplitude amplification device that is disposed at the rear side of the hydraulic tube, an oscillator that is disposed at the rear side of the amplitude amplification device so as to be deformed and increases and decreases a pressure within the hydraulic tube, and an oscillator head that is attached to a front end of the oscillator.

Abstract: A drive train configuration is disclosed. The drive train configuration has a transmission or transaxle assembly which may be directly mounted to a vehicle frame. The drive train configuration also comprises an engine that may be attached to a housing of the transmission or transaxle portion. The drive train configuration may also have a power take off mechanism.

Abstract: A work vehicle has a pump group with two fixed-displacement pumps, an electro-hydraulic diverter openable to divert flow from one of the pumps to a fluid reservoir, and a controller configured to command the diverter to open.

Abstract: A fluid delivery system includes a first hydraulic circuit, and a second hydraulic circuit. The first hydraulic circuit includes a first hydraulic pump, and a first hydraulic motor. The first hydraulic motor is fluidly connected to the first hydraulic pump and is configured to be driven by the first hydraulic pump. The second hydraulic circuit includes a second hydraulic pump, and a second hydraulic motor. The second hydraulic pump is mechanically coupled to the first hydraulic motor and configured to be driven by the first hydraulic motor. The second hydraulic motor is disposed in loop with the second hydraulic pump and configured to be driven by the second hydraulic pump. The fluid delivery system further includes a delivery pump mechanically coupled to the second hydraulic motor and fluidly connected to a fluid source. The delivery pump is configured to deliver a pressurized fluid.

Abstract: A hydraulic system having an actuator having a piston and associated rod forming head and rod chambers and being adapted to move between retracted and extended positions within a cylinder, and first and second sources of fluid. A first pump provides fluid from the first source to the head chamber at a first pressure. At least one valve provides fluid from the second source at a second pressure to supplement fluid provided to the head chamber from the first pump when the second pressure is greater than the first pressure.

Abstract: A wood chipping system including a vehicle having an engine and a power take off attached to and selectively powered by the engine. A hydraulic pump is positioned on the vehicle and is driven by the power take off. The system can include a towable support having a chipper mounted thereon, the chipper having a chipper drum driven by a hydraulic motor, the hydraulic motor driving a hydraulic pump that drives a feed roll system of the chipper. The system can include a brake valve associated with the main motor to stop rotation of the chipper drum.

Abstract: A hydraulic system includes a variable displacement first pump, a first linear actuator fluidly connected to the first pump via a first closed-loop circuit, a variable displacement second pump, and second and third linear actuators fluidly connected to the second pump in parallel via a second closed-loop circuit. The system also includes a variable displacement third pump, a fourth linear actuator fluidly connected to the third pump via a third closed-loop circuit, a variable displacement fourth pump, and a first rotary actuator fluidly connected to the fourth pump via a fourth closed-loop circuit. The system further includes a second rotary actuator fluidly connected to the second pump in parallel with the second and third linear actuators. The system also includes a third rotary actuator fluidly connected to the third pump in parallel with the fourth linear actuator.

Abstract: A hydraulic system is disclosed having first, second, and third pumps. The hydraulic system may also have a first actuator connected to the first pump in closed-loop manner, a second actuator connected to the second pump in closed-loop manner, and a third actuator. The hydraulic system may further have a selector valve associated with the third pump, and a first switching valve associated with the third pump and the third actuator. The first switching valve may be movable between a first position at which the third pump is connected to the third actuator in a closed-loop manner to move the third actuator in a first direction, a second position at which the third pump is connected to the third actuator in a closed-loop manner to move the third actuator in a second direction, and a third position at which the third pump is connected to the selector valve.

Abstract: A pneumatic system controlling a bath crust breaker includes a cylinder defining a piston chamber. A piston is slideably displaced within the cylinder by pressurized fluid directed to either a piston chamber first portion with respect to the piston or a piston chamber second portion oppositely positioned about the piston. A pneumatic valve system includes a first control valve aligned between first control valve first and second positions, the first control valve first position aligned with the first portion, and in the first control valve second position is aligned with the second portion. A second control valve is aligned between second control valve first and second positions. An orifice between a pressure source and first control valve is sized to control fluid flow rate so a pressure reached in either the first or second portion during a crust breaking cycle is less than a pressure source maximum pressure.

Abstract: A hydraulic transaxle comprises a transaxle housing, an axle, a hydraulic pump, a hydraulic motor, a hydraulic circuit, and a pair of auxiliary pumps. The transaxle housing defines a fluid sump therein. The axle is supported by the transaxle housing. The hydraulic motor is disposed in the transaxle housing so as to drive the axle. The hydraulic pump is disposed in the transaxle housing so as to supply hydraulic fluid to the hydraulic motor. The hydraulic circuit is disposed in the transaxle housing so as to fluidly connect the hydraulic pump to the hydraulic motor. The pair of auxiliary pumps are disposed in the transaxle housing so as to supply fluid from the fluid sump to outside of the transaxle housing.

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 control device that controls a hydraulic pressure for a plurality of friction engagement elements included in an automatic transmission mounted on a vehicle to establish a plurality of shift speeds, including: a plurality of pressure regulation valves, a plurality of hydraulic switches, speed change control means, and abnormality determination means.

Abstract: A hydraulic system for a vehicle includes a first hydraulic circuit, a second hydraulic circuit, and a main actuator. The first hydraulic circuit includes a first pump having a flow outlet; a first pressure line having a pump end coupled to the flow outlet of the first pump; and a first load sensing line having a pump end coupled to the first pump and a pressure end coupled to the first pressure line. The second hydraulic circuit includes a second pump having a flow outlet; a second pressure line having a pump end coupled to the flow outlet of the second pump; and a second load sensing line having a pump end coupled to the second pump and a pressure end coupled to the second pressure line. The main actuator is coupled to the first pressure line and the second pressure line and is configured to oppose a load force. The first load sensing line is separate from the second load sensing line such that the first pump and the second pump respond independently to the load force.

Abstract: The invention captures harvestable mechanical energy, e.g., in the form of wind or moving water, and uses it for electrical generation or other work. In various embodiments a turbine is used to pressurize a fluid, and the pressurized fluid is then optionally stored and then used to drive an electric generator. Because the pressurized fluid can be stored in a pressurized state indefinitely, the invention provides a straightforward way to accumulate the mechanical energy until it is needed. Additionally, the invention allows portions of the system, e.g., a pressure vessel or generator, to be located away from the turbine, reducing the costs of deploying and maintaining the system.

Abstract: A smart flow sharing system, useful in hydraulic systems having more than one hydraulically demanding equipment function wherein more than one of the hydraulically demanding functions are sometimes activated at the same time, has modified hydraulic passages and at least two fixed displacement pumps. The system automatically prioritizes hydraulic fluid flow so that when only one of two hydraulically demanding functions is activated by an operator, it receives the hydraulic fluid flow from both fixed displacement pumps, but when both hydraulically demanding functions are activated, one of the functions receives hydraulic fluid flow from the first fixed displacement pump, and the other function separately receives hydraulic fluid flow from the second fixed displacement pump. The smart flow sharing system accomplishes the foregoing without resorting to complex hydraulics or expensive additional components.

Abstract: A working vehicle, wherein flows of hydraulic oil delivered under pressure from two or more hydraulic pumps are joined together and the joined hydraulic oil can be taken out. A working vehicle is provided with two hydraulic pumps independent of each other and adapted to deliver hydraulic oil under pressure, a mode switching valve (230) capable of being switched to a flow joining position (K) at which flows of the hydraulic oil delivered under pressure by the two hydraulic pumps are joined together, PTO ports (260, 261) out of which the hydraulic oil is taken, and a PTO switching valve (240) provided downstream of the mode switching valve (230) and switching flow of the hydraulic oil so that the oil can be delivered under pressure to the PTO ports (260, 261).

Abstract: A center section or other mounting member for mounting and hydraulically connecting a pump and motor, includes a first piece having a running surface for the pump and connected to hydraulic porting and a second separable piece having a running surface for the motor and connected to the hydraulic porting. A spacer is disposed between the first piece and the second piece for hydraulically connecting the first piece and the second piece and for modifying the distance between the pump running surface and the motor running surface, whereby the first piece is physically separated from the second piece. Two such mounting members may be used at opposite ends of a main housing with a drive device having two pumps and two motors.

Abstract: A pair of dozer control valves V3, V6 concurrently operable; a pilot pressure valve V14 switchable between an independent position 27 where, when only track devices 5 are operated, discharged fluid from one hydraulic-fluid discharge port P1 is independently supplied to one track control valve and one dozer control valve, and discharged fluid from the other hydraulic-fluid discharge port P2 is independently supplied to the other track control valve and the other dozer control valve, and a merging position 28 where, when the other control valves are operated, discharged fluid from the one hydraulic-fluid discharge port and from the other hydraulic-fluid discharge port are merged and supplied to the control valves V1 to 10; and pressure compensation valves V11 in the control valves and for distributing hydraulic fluid at flow rates based on extent of actuation of the other control valves operated, irrespective of the magnitude of the loads.

Abstract: A hydraulic drive device for a hydraulic excavator, includes: a first hydraulic pump; a first boom directional control valve and a second arm directional control valve which are connected in parallel to the first pump; a second hydraulic pump; and a second boom directional control valve and a first arm directional control valve which are connected in parallel to the second pump; wherein: the hydraulic drive device also includes: a third hydraulic pump; a third boom directional control valve connected to the third pump and controlling the flow of pressure oil supplied to a boom cylinder; and a third arm directional control valve connected in tandem with the third boom directional control valve and controlling the flow of pressure oil supplied to an arm cylinder.