Abstract: A method and system for controlling the dynamics of an actuatable load functioning or operable within a servo or servo-type system, wherein the dynamics of the load are controlled by way of a unique pressure control valve configured to provide intrinsic pressure regulation. The pressure control valve comprises dual spools physically independent of one another and freely supported in a valve body to regulate the pressures acting within the overall system between the control or pilot pressure and the load or load pressure. The dual spools of the pressure control valve, although physically independent of one another, function in cooperation with one another in an attempt to maintain a state of equilibrium in the system, namely to keep pressure acting on or within the actuator (the load pressure), or the feedback force corresponding to the load pressure, the same as the control or pilot pressure.

Abstract: To simplify a circuit structure and a path structure in a hydraulic circuit having a pilot check valve and an overload relief valve and to reduce the size of a gear. The hydraulic circuit includes a pump port; a tank port; a first actuator port; a second actuator port; a first supply and discharge port; a second supply and discharge port; a direction changing valve; a first pilot check valve; a second pilot check valve; a first pilot path; and a first overload relief valve. The direction changing valve has a neutral position to communicate the first supply and discharge port with the tank port. The first overload relief valve is arranged in parallel with the first pilot check valve and is arranged between the first supply and discharge port and the first actuator port.

Abstract: Disclosed is a hydraulic control circuit and method thereof for reducing heat generation and energy losses caused by overload.

Abstract: What is disclosed is a hydraulic control arrangement for controlling a hydraulic consumer, comprising an adjustable supply measuring orifice and an adjustable drain measuring orifice as well as a pressure compensator arranged in a pressure medium delivery. The control arrangement moreover comprises a releasable cut-off block that acts as a check valve in the direction of supply and may be released in the direction of drain by means of a control pressure. In accordance with the invention, the pressure compensator is subjected to a constant force in the opening direction and to the lower one of the pressures downstream from the supply measuring orifice and upstream from the drain measuring orifice in the closing direction.

Abstract: The invention relates to a hydraulic actuating device for a movable component of a vehicle, in particular a closure element for closing an opening in a vehicle body, such as for example a movable roof, such as a folding roof or a retractable hard top.

Abstract: A poppet valve assembly with a control chamber that can be fluidly connected to a number of different hydraulic ports via a pilot valve assembly. The poppet valve assembly includes a poppet valve member whose movement is controlled by filling or draining the control chamber, and which can be hydraulically locked into a given position by fluidly isolating the control chamber from any other hydraulic connections. The poppet valve member includes a control hydraulic surface exposed to fluid pressure in the control chamber. The poppet valve assembly may be part of a valve assembly that includes a plurality of poppet valve assemblies that operably control a hydraulic cylinder connected to an implement of a work machine.

Abstract: The present disclosure is directed to a valve system including a controller and a valve including a valve element and a valve bore. The valve element is selectively movable relative to the valve bore at least partially in response to a signal communicated from a controller. The communicated signal is at least partially based on a load on the actuator and a determined pressured drop. The determined pressure drop is at least partially based on a hysteretic filter.

Abstract: A power transmission device includes a rotary input member receiving drive torque from a source of torque, a rotary output member for providing drive torque to an output device and a torque transfer mechanism for transferring drive torque between the input member and the output member. The torque transfer mechanism includes a friction clutch assembly operably disposed between the input member and the output member and a hydraulic clutch actuation system operable for applying a clutch engagement force to the friction clutch assembly. The hydraulic clutch actuation system includes an electric motor drivingly coupled to the hydraulic actuator. The hydraulic actuator includes a first piston biasedly engaged by a spring, slidably positioned within a housing and operable to supply pressurized fluid to a second piston. Supply of pressurized fluid to the second piston provides the clutch engagement force.

Abstract: A power transmission device includes a rotary input member adapted to receive drive torque from a source of torque, a rotary output member adapted to provide drive torque to an output device and a torque transfer mechanism operable to transferring drive torque from the input member to the output member. The torque transfer mechanism includes a friction clutch assembly operably disposed between the input member and the output member and a hydraulic clutch actuation system operable for applying a clutch engagement force to the friction clutch assembly. The hydraulic clutch actuation system includes an electric motor drivingly coupled to a first piston. The first piston is slidably positioned within the housing for supplying pressurized fluid to an accumulator. The pressurized fluid within the accumulator is in communication with a second piston to provide the clutch engagement force.

Abstract: The load element state detecting portion 72 detects the completion of the filling of the hydraulic oil into the clutch 62 and the working limit of the accumulator 64 on the basis of the displacement of the spool valve element 42. That is, since the completion of the filling of the hydraulic oil into the clutch and the working limit of the accumulator 64 are directly detected, so that the completion of the filling of the hydraulic oil into the clutch 62 and the working limit of the accumulator 64 can be detected with high precision regardless of differences among products and the time-lapse variation. Furthermore, they can be detected without equipping any special device to the hydraulic control circuit, and thus there is an advantage that the device construction is simple.

Abstract: An apparatus controls fluid flow to an actuator. A feedback mechanism responds to a pressure differential that occurs across the actuator by altering the fluid flow. That pressure differential indicates acceleration of the actuator that can occur when the load acting thereon varies. Thus as the actuator accelerates, the apparatus reduces the flow of fluid which counteracts the acceleration and maintains the actuator speed relatively constant. A unique directional control valve incorporates the feedback mechanism that functions regardless of the direction in which the actuator moves.

Abstract: The invention relates to a hydraulic cylinder comprising a piston rod bearing at least one tool receiving element. Said hydraulic cylinder is characterized by an automatic disconnection device which is controlled in a hydraulic-mechanical manner, with a medium for the actuation of the hydraulic cylinder. Said medium which is used for building-up force, is also the medium which is used for the automatic disconnection device. Said hydraulic cylinder also comprises a first valve slider and a second valve slider which are used for disconnecting the displacement of a piston, which is connected to a piston rod according to a possible obstruction found in the path of the outward moving piston rod before a desired position by deviating the medium in the region of the piston.

Abstract: A position control system is used for controlling a fluid operated cylinder having at least one fluid chamber defined by a piston located within a housing for movement between first and second end limits of travel. The system includes at least two electrically actuated proportional flow control valves connected to each port of the cylinder for selectively and proportionally controlling fluid flow into and out of the at least one chamber. At least one pressure sensor is provided for measuring fluid pressure with respect to each chamber. At least one discrete position sensor is located adjacent a midpoint of the cylinder for sensing a discrete centered position of the piston. A controller includes a program and is operably connected for controlling actuation of the at least two valves in response to pressure measured by the at least one pressure sensor and location measured by the at least one position sensor.

Abstract: A fluid pressure control circuit includes a fluid pressure device which is operated by a fluid pressure; a control valve which is connected to the fluid pressure device via a connecting passage, and which changes a flow rate of predetermined fluid that is to be supplied to the fluid pressure device or that is to be discharged from the fluid pressure device according to a position of a valve element; and a pressure difference reflecting device which moves the valve element based on a difference in the fluid pressure between predetermined two different portions in the connecting passage and which changes the flow rate of the fluid that is to be supplied or to be discharged through the control valve according to the fluid pressure difference. With this fluid pressure control circuit, it is possible to obtain excellent responsiveness during supply/discharge of the fluid, change in the fluid pressure or the like, without increasing the amount of the fluid to be consumed.

Abstract: An actuator device self-contained within a housing and adapted to move an object. The actuator device includes a movable piston positioned in a cylinder portion of the housing. The cylinder portion defines a longitudinal axis, whereby the piston is movable along the longitudinal axis in response to an accumulation of air pressure within the cylinder portion. The actuator device also includes a rod coupled to the piston for movement with the piston. The rod at least partially extends outside of the housing to couple to the object. Further, the actuator device includes an air compressor located within the housing. The air compressor transfers air from a location in the housing outside the cylinder portion to a location inside the cylinder portion.

Abstract: To perform boom-down operation by operating a boom cylinder (6) by an external load (W) while simultaneously operating an arm cylinder (26) or a bucket cylinder (27) in the state the bucket is off the ground, a first boom directional control valve (2) and a regeneration boom valve (13) are controlled to the neutral position and the open position respectively so that the hydraulic oil is regenerated from a line (9) located at the oil-returning side of the boom cylinder (6) through the regeneration boom valve (13) to a line (5) located at the oil-feeding side. Therefore, the volume of the hydraulic oil that can be supplied from the pressurized oil source (4) to the arm cylinder (26) or the bucket cylinder (27) via the second arm directional control valve (24) or the bucket directional control valve (25) is increased by the amount equivalent to the amount of the oil that is not supplied from the pressurized oil source (4) to the boom cylinder (6).

Abstract: A pressure regulating valve (20) for adjusting a pressure of a supply/discharge passage (10) to a pressure balanced against a weight of a body to be carried (1) is provided. The supply/discharge passage (10) is connected to a working chamber (8) of a cylinder (2) for raising and lowering the body to be carried (1). A control valve (38) for increasing and decreasing a pressure in a control passage (28) in accordance with a balance between the weight of the body to be carried (1) and a working force in a reaction force chamber (42) to which a pilot pressure is introduced from the control passage (28) is also provided.

Abstract: A pressure control apparatus is disposed in a pressure control system for a transmission to set pressure control at a torque-transmitting mechanism. The pressure control apparatus includes a torque-transmitting mechanism control valve, which distributes pressure from a high pressure source to the torque-transmitting mechanism. Also within the pressure control apparatus is a boost valve mechanism, which is effective to control feedback pressure on the torque transmitting mechanism pressure regulator valve thereby controlling the pressure rise at the torque-transmitting mechanism and also permitting a boost pressure to be distributed to the torque-transmitting mechanism when full engagement thereof is required.

Abstract: In the present invention, sensors for cylinder control are connected to a main cylinder which has an internal cylinder chamber which is partitioned by a piston into two chambers, and they detect the operational state of the piston. There are provided accumulators connected to one of said two chambers by connecting conduits and whose interiors are pressurized by hydraulic fluid which is expelled from said one chamber, and also stop signal generation mechanisms which generate signals to stop the driving of said main cylinder by pressure differential between said accumulators and said connecting conduits generated at the instant that increase of pressure from said one chamber stops.

Abstract: A valve, especially a pressure control valve, includes a housing (10) with a pump connection (P), an appliance connection (A) and a tank connection (T). A piston (16) controlled by a magnet armature (26) is guided inside the housing (10) of the valve. The vavle is provided with a hydraulic damping device (34) having a damping chamber (36) in fluid communication with appliance connection (A) through a throttle (38). The pump connection (P) or the tank connection (T) is selectively joined to the appliance connection (A) via a connecting line (40) according to the position of the piston (16). This valve improves upon known control valves so that the control valve remains stable in terms of behavior, especially with regard to permanent oscilliations.

Abstract: A control valve system including a housing having an inlet, a first output, and a second output. The control valve system further includes a slidable valve positionable in a first position, where fluid communication is established between the inlet and the first output; a second position, where fluid communication is established between the inlet and the second output; and a third position, where fluid communication is prevented between the inlet and the first or second output. A solenoid valve assembly is coupled in fluid communication with the inlet and is positionable in an actuated position, where fluid communication is established with the inlet to move the valve from the first position to the second position, and a deactuated position. A piston selectively extendable to position the valve in the third position in response to fluid pressure within the first output.

Abstract: A control valve system including a housing having an inlet, a first output, and a second output. The control valve system further includes a slidable valve positionable in a first position, where fluid communication is established between the inlet and the first output; a second position, where fluid communication is established between the inlet and the second output; and a third position, where fluid communication is prevented between the inlet and the first or second output. A solenoid valve assembly is coupled in fluid communication with the inlet and is positionable in an actuated position, where fluid communication is established with the inlet to move the valve from the first position to the second position, and a deactuated position. A feedback passage extends between the first output and the valve so as to position the valve in the third position in response to fluid pressure within the first output.

Abstract: The flow of fluid to a hydraulic actuator is controlled by a valve assembly which operates in different metering modes at various points in time. The metering mode to use in selected in response to the hydraulic load that acts on the valve associated with the hydraulic actuator. Specifically the load is determined and then compared to threshold levels associated with the different metering modes to choose the metering mode for use a given point in time.

Abstract: When a swinging boom driven by a hydraulic cylinder stops, inertia causes continued motion of the boom which increases pressure in a chamber of the hydraulic cylinder. Eventually that pressure reaches a level which causes the boom to reverse direction. Then pressure in an opposite cylinder chamber increases until reaching a level that causes the boom movement to reverse again. This oscillation continues until the motion is dampened by other forces acting on the boom. As a result, an operator has difficulty in properly positioning the boom. To reduce this oscillating effect, a sensor detects when the cylinder chamber pressure increases above a given magnitude and then a determination is made when the rate of change of that pressure is less than a defined threshold. Upon that occurrence, a control value is opened to relieve the pressure in that cylinder chamber.

Abstract: An actuator is part of a hydraulic circuit branch that has a first electrohydraulic proportional valve connecting the actuator to a supply line containing pressurized fluid and a second electrohydraulic proportional valve connecting the actuator to a tank return line. A method for operating the valves includes requesting a desired velocity for the hydraulic actuator and sensing a parameter which varies with changes of a force on the actuator. The desired velocity and the parameter are used to derive an equivalent flow coefficient which characterizes fluid flow in the hydraulic circuit. From the equivalent flow coefficient, first and second valve flow coefficient are derived and then employed to activate each of the first and second electrohydraulic proportional valves. The coefficients may characterize either conductance or restriction in the respective part of the hydraulic system.

Abstract: A hydraulic circuit branch includes a hydraulic actuator, such as a cylinder, and an assembly of one or more electrohydraulic proportional valves connected in series between a pressurized fluid supply line and a tank return line. The force acting on the hydraulic actuator is determined by sensing fluid pressures produced by the hydraulic actuator. Pressures in the supply and tank return lines also are sensed. The sensed pressures and a desired velocity for the hydraulic actuator are employed to determine an equivalent flow coefficient, which characterizes fluid flow through the hydraulic circuit branch, either a conduction or restriction coefficient may be derived. The equivalent flow coefficient is used to determine how to activate each electrohydraulic proportional valve to achieve the desired velocity of the hydraulic actuator. The equivalent flow coefficient also is employed to control the pressure levels in the supply and tank return lines.

Abstract: When a swinging boom driven by a hydraulic cylinder stops, inertia causes continued motion of the boom which increases pressure in a chamber of the hydraulic cylinder. Eventually that pressure reaches a level which causes the boom to reverse direction. Then pressure in an opposite cylinder chamber increases until reaching a level that causes the boom movement to reverse again. This oscillation continues until the motion is dampened by other forces acting on the boom. As a result, an operator has difficulty in properly positioning the boom. To reduce this oscillating effect, a sensor detects when the cylinder chamber pressure increases above a given magnitude and then a determination is made when the rate of change of that pressure is less than a defined threshold. Upon that occurrence, a control value is opened to relieve the pressure in that cylinder chamber.

Abstract: A method for controlling a hydraulic system may include receiving an input command from an input device, generating a desired working pressure value relating to a working chamber of an actuator based on the input command, and generating a desired pressure value relating to a non-working chamber of the actuator based on the input command. The method may also include operating a valve assembly to control a fluid flow condition of the working chamber and to control fluid flow from the non-working chamber.

Abstract: A system and method for controlling an electro-hydraulic valve arrangement to perform a pump check function are provided. The system includes an electro-hydraulic valve arrangement disposed between a source of pressurized fluid and a hydraulic actuator. Pressure sensors are provided to sense a source pressure representative of the fluid pressure between the source of pressurized fluid and the electro-hydraulic valve arrangement and an actuator pressure representative of the fluid pressure between the electro-hydraulic valve arrangement and the actuator. A control device receives a signal to open the electro-hydraulic valve arrangement to provide a requested flow rate to the hydraulic actuator. The received signal is modified to prevent fluid flow through the electro-hydraulic valve arrangement when the source pressure is less than the actuator pressure.

Abstract: One aspect of the control system provides a hydraulic control system for a transfer case that includes an actuator for generating fluid pressure. The system also includes an isolation valve and a control valve in fluid communication with the actuator. The isolation valve is in a normally closed position and the control valve is in a normally open position. The system further includes a piston for applying fluid pressure to a device of the transfer case. Another aspect provides a method for controlling the hydraulic pressure to a transfer case.

Abstract: A hydraulic control system for controlling expansion and contraction of a cylinder. The cylinder comprises an extension chamber and a contraction chamber. The hydraulic control system comprises a first servovalve comprising a first pressure supply port and a first pressure discharge port and adapted to selectively communicate the expansion chamber with the first pressure supply port and with the first pressure discharge port. A second servovalve, comprising a second pressure supply port and a second pressure discharge port, is adapted to selectively communicate the contraction chamber with the second pressure supply port and with the second pressure discharge port.

Abstract: An auto-relieving pressure modulating valve includes a spool, a solenoid that shifts the spool in an energized direction, and a spring arrangement. The spring arrangement functions to shift the spool from a relieving position to a neutral position, in the energized direction, without energizing the solenoid.

Abstract: A method for controlling a hydraulic system may include receiving an input command from an input device, generating a desired working pressure value relating to a working chamber of an actuator based on the input command, and generating a desired pressure value relating to a non-working chamber of the actuator based on the input command. The method may also include operating a valve assembly to control a fluid flow condition of the working chamber and to control fluid flow from the non-working chamber.

Abstract: A pressure control valve under the control of a pilot pressure generates a working pressure for a pressure-actuated apparatus. The valve has a control piston with two piston elements of different diameter. A working-pressure chamber is confined between the two piston elements, and a pilot-pressure chamber is confined between one of the control-piston elements and an additional piston. The additional piston takes a position dependent on a momentarily existing difference between the working pressure and the pilot pressure and, through an elastic force-coupler device, applies a position-dependent force to the control piston.

Abstract: A hydraulic valve having a kinked characteristic curve is provided for a hydraulic consumer of a motor vehicle.

Abstract: In a pressure regulation valve having a main spool and a sub-spool slidably housed in the main spool, the main spool is at a position where pilot pressure force balances with a sum of pressure force of a feedback chamber and spring biasing force, when the pilot pressure is below a given value, so that normal output pressure proportional to pilot pressure is supplied to a hydraulic servo for driving a clutch of an automatic transmission, and, when the pilot pressure exceeds the given value, the sub-spool moves to a position where the feedback chamber communicates with a drain so that the main spool moves to a position where maximum output pressure equal to supply pressure source is supplied.

Abstract: A valve device includes a valve housing with at least one inlet channel and an outlet channel. A valve piston can be moved axially in the valve housing and has control edges for releasing and blocking the connection between the cross sections of the inlet and outlet channels. A regulating device applies the actuating force to the valve piston. Elements produce a force opposing the actuating force through at least a part (a proportional area) of the overall working range of the valve device, depending on the pressure in the outlet channel.

Abstract: A self-calibrating method and system 10 for controlling a hydraulically operated device, such as a clutch actuator 24 in an automatic power transmission, provides a pressure switch 30 in the hydraulic circuit that provides feed-back to the controller 32 when the hydraulic fluid pressure has reached a set point level. Pressure switch 30 provides a signal to controller 32 that allows the controller to compare the control signal at the pressure set point level with that of the calibrated curve for adjusting the calibration curve.

Abstract: An electrohydraulic valve control system which enables simultaneous flow and pressure control for operating an implement or other work element associated with a work machine through the use of a single control valve design, the present control system comparing the actual valve output flow rate of the hydraulic fluid flowing through the valve to a desired valve output flow rate and thereafter modifying the input flow rate to the valve based upon the difference between the actual valve output flow rate and the desired valve output flow rate. The desired valve output flow rate is determined based upon the actual load pressure being exerted against the implement or work element and the operator input signal generated by the operator upon activation of an operator input control mechanism used to control the operation of the implement or work element.

Abstract: A hydraulic force servo system provides apparatus for compensating for unequal loading forces applied to an actuator piston, and for unequal areas on opposite faces of the piston. Asymmetric nonlinear differential hydraulic force feedback from the output side of a force servovalve is summed with the hydraulic control signal inputs to the output stage of the servovalve at hydraulic summing junctions. Impedances offered by orifices in the feedback lines determine the amount of feedback. Nonlinear characteristics of the feedback method serve to compensate for nonlinearities in the servo actuator and system. The impedance ratio of the orifices is selected as a function of the known or postulated asymmetry of the loading forces to be applied to the actuator piston, and the ratio of the areas of the opposing faces of the actuator piston. Hydraulic damping further improves linearity and stability.

Abstract: An improved paint ball gun and improved rotary breech, regulator, control valve, power piston and power valve assemblies for utilization in paint ball guns or related devices. The paint ball gun eliminates moving metal to metal surfaces to provide a consistent operation and easy regulation. The paint ball gun has a rotary breech to minimize damage to paint balls utilized in the paint ball guns.

Abstract: A hydraulic remote control (HRC) valve including a main spool valve and a pilot pressure control valve. A lever is operatively connected to the pilot valve whereby to provide “finger tip” control of the main spool valve. The HRC has an inverting output, whereby movement of the lever away from a neutral position causes a decrease in hydraulic pressure supplied to a hydraulic clutch. In practice, two HRC's according to the invention are embodied in a single housing. The HRC of the invention is of use in controlling the hydraulic steering clutches of tracked vehicles.

Abstract: A trim valve controls the pressure rise and pressure gain in a torque transmitter. The trim valve controls the distribution of a system pressure to the torque transmitter in a controlled manner such that the apply pressure of the torque transmitter has a desired gain rate. A spool valve controls the admission of system pressure through a sleeve valve for distribution to the torque transmitter in response to a control pressure. The trim valve has bias spring elements that control a sleeve member of the trim valve in response to the apply pressure at the torque transmitter. The rate at which the apply pressure rises in relation to the control pressure is established by the bias spring elements which can be a single variable rate member or a plurality of parallel members. If parallel members are used, they are positioned to be sequentially engaged by the sleeve valve during linear movement in response to a change in the apply pressure.

Abstract: A gas actuating device includes a housing having a gas applying chamber, an actuator chamber and a gas applying passage for communicating gas from the gas applying chamber to the actuator chamber. An actuating member having a first side and a second side is disposed in the actuator chamber, wherein the first side of the actuating member receives gas pressure from gas applied to the actuating chamber from the gas applying passage. The actuating member moves in a first direction in response to the gas pressure applied to the first side of the actuating member. A valve selectively communicates compressed gas from the gas applying chamber to the actuator chamber through the gas applying passage for moving the actuating member in the first direction, and a gas release passage communicates gas from the actuator chamber at the first side of the actuating member to an outside of the actuator chamber.

Abstract: An hydraulic valve has two outlets and is switchable so that fluid can only be supplied to one outlet at a time. A spool with two seals is slidable in a housing under the action of two proportional solenoids and is urged to a central position by two springs where the seals block passage to both outlets. When the spool is moved in one direction it allows flow to one outlet and also allows flow via a bypass channel to an opposite side of the spool counteracting the force applied by the solenoid so that the force applied to an outlet can be controlled gradually.

Abstract: A system and method for controlling an independent metering valve operating in a hydraulic circuit determines a displacement command for one or more metering valves to provide desired flows through the metering valves and desired pressure drops across the metering valves. The system determines the displacement command based on a mode of operation of the hydraulic circuit and a velocity for a hydraulic device controlled by the hydraulic circuit. The system determines the displacement command further based on an amount of flow available to the hydraulic circuit. The system allows the hydraulic circuit to be electronically controlled thereby providing flexibility not found in conventional hydraulic control systems.

Abstract: A system and method for controlling an independent metering valve operating in a hydraulic circuit determines a displacement command for one or more metering valves to provide desired flows through the metering valves and desired pressure drops across the metering valves. The system determines the displacement command based on a mode of operation of the hydraulic circuit and a velocity for a hydraulic device controlled by the hydraulic circuit. The system determines the displacement command further based on an amount of flow available to the hydraulic circuit. The system allows the hydraulic circuit to be electronically controlled thereby providing flexibility not found in conventional hydraulic control systems.

Abstract: A pressure control valve system for a friction device has a regulator valve with a plurality of pressure feedback differential areas which are selectively pressurized during the engagement of a friction device to control the apply pressure at one rate during normal operation and at a higher rate during high torque demand operation. A plug valve is disposed adjacent the regulator valve to establish two variable control forces acting on the regulator valve in response to a variable control pressure. The combination of the differential areas and the plug valve permit the regulator valve to establish two distinct pressure gain functions, each of which has a knee or inflection point resulting in two pressure gain ratios.

Abstract: A control system for improving the roadability of a wheeled excavator is disclosed herein. The excavator is the type including an implement such as a bucket or backhoe which is moved relative to the excavator by hydraulic actuators. Hydraulic fluid is applied to the actuators via electronic valves which are controlled by an electronic controller. Based upon acceleration of the vehicle, the electronic controller controls the electronic valve to maintain fluid pressure in the actuator or the acceleration substantially constant. Additionally the controller can be configured to maintain the average position of the implement generally constant. By controlling the pressure in the hydraulic actuator, the undesirable bouncing or pitching of the excavator can be reduced when the vehicle is traveling at road or loading speeds.

Abstract: A control system for improving the roadability of a wheeled excavator is disclosed herein. The excavator is the type including an implement such as a bucket or backhoe which is moved relative to the excavator by hydraulic actuators. Hydraulic fluid is applied to the actuators via electronic valves which are controlled by an electronic controller. Based upon acceleration of the vehicle, the electronic controller controls the electronic valve to maintain fluid pressure in the actuator or the acceleration substantially constant. Additionally, the controller can be configured to maintain the average position of the implement generally constant. By controlling the pressure in the hydraulic actuator, the undesirable bouncing or pitching of the excavator can be reduced when the vehicle is traveling at road or loading speeds.