Abstract: An oil supply device for a vehicle includes an oil pump driven by a rotation of an internal combustion engine, a hydraulic actuator to which oil is supplied from the oil pump, an engine lubricating system to which the oil is supplied from the oil pump, an oil supply adjusting valve adjusting a supply condition of the oil from the oil pump to the hydraulic actuator and the engine lubricating system, a first oil supply passage supplying the oil from the oil pump to the hydraulic actuator, and a second oil supply passage supplying the oil from the oil pump to the engine lubricating system, wherein the oil supply adjusting valve consistently distributes the oil to the first oil supply passage and the second oil supply passage.

Abstract: A hydraulic circuit for an excavator is provided, which includes at least one first working device control valve having a first traveling control valve and a first boom control valve successively installed along a first center bypass line from a downstream side of a first hydraulic pump, at least one second working device control valve having a second traveling control valve and a second boom control valve successively installed along a second center bypass line from a downstream side of a second hydraulic pump, a third hydraulic pump providing fluid pressure to a swing motor installed on a third center bypass line, a swing control valve installed on a downstream side of the third hydraulic pump and shifted, in accordance with a valve switching signal input from the outside, to supply hydraulic fluid discharged from the third hydraulic pump to the swing motor, and a boom confluence line connected between an output port of the swing control valve and an input port of the boom control value to make the hydrauli

Abstract: A stack valve 1 includes a boom direction switching valve 11 (first direction switching valve) connected to an unloading path 21 and a service valve 13 (second direction switching valve) connected to the unloading path 21 at the downstream of the boom direction switching valve 11. At changeover positions 11a and 11c at which the unloading path 21 on the upstream side is connected to one of the supply and discharge paths 29 and 30 and the other one of the supply and discharge paths 29 and 30 is connected to the unloading path 21 on the downstream side, the boom direction switching valve 11 is connected to a boom valve tank return path 27 which connects the other one of the supply and discharge paths 29 and 30 with the tank path 22.

Abstract: A controller carries out horsepower control to determine a flow rate of a hydraulic pump based on first characteristics and second characteristics, which each define a maximum input setting of the hydraulic pump by a discharge pressure of the hydraulic pump and a flow rate of the hydraulic pump, and based on the discharge pressure. When the discharge pressure is less than a set pressure and when a state where the discharge pressure is equal to or greater than the set pressure has not continued for a set time period, then the controller determines the flow rate based on the first characteristics, and when the state where the discharge pressure is equal to or greater than the set pressure has continued for the set time period, then the controller determines the flow rate based on the second characteristics.

Abstract: The present invention provides a system for driving a working machine, while the system achieves high energy saving, the system improving installability by downsizing hydraulic pumps and motors, and having extensibility enabling an attachment to be easily added. A system for driving a working machine according to the invention includes: a plurality of hydraulic closed circuits that connect hydraulic pumps to hydraulic actuators in a closed circuit manner; hydraulic open circuit that connects a hydraulic pump to hydraulic actuators in an open circuit manner; first assist circuits that connect between the hydraulic closed circuits so as to cause a hydraulic fluid to be mutually supplied between the hydraulic closed circuits; and second assist circuits that connect the hydraulic closed circuits to the hydraulic open circuit so as to cause the hydraulic fluid to be supplied from the hydraulic closed circuits to the hydraulic open circuit.

Abstract: Disclosed is a hydraulic pump for construction machinery for controlling to inhibit one-way driving when compound-operating two-way driving and work devices, such as a boom, to enhance operation efficiency.

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a pump configured to pressurize fluid, a displacement control valve configured to affect displacement of the pump, and a tool control valve configured to receive pressurized fluid from the pump and to selectively direct to the pressurized fluid to a hydraulic actuator. The hydraulic control system may also have a controller in communication with the displacement control valve. The controller may be configured to determine a pressure gradient across the tool control valve substantially different than a desired pressure gradient, to determine a desired condition of the displacement control valve based the pressure gradient, and to determine a flow force applied to the displacement control valve based on the desired condition. The controller may be further configured to generate a load sense response signal directed to the displacement control valve based on the desired condition and the flow force.

Abstract: A fluid system and method of operation provides flow force compensation and load sense functions. Each work circuit includes an actuator, a control valve, and a first valve. A valve element of a control valve includes main metering orifices sized and shaped to provide flow force compensation. A load sense check valve associated with a load pressure signal conduit is downstream of the load check valve. The load pressure signal conduit of each work circuit is in fluid communication with one another, and a greater of the load signal pressure of the work circuits is communicated to the load sense check valve of the other work circuit. The control valve associated the lesser load can permit flow forces to reduce the effective area of the orifice, which increases the pressure difference across the valve to maintain approximately constant flow to the actuator.

Abstract: A hydraulic traveling vehicle includes a right-travel motor a left-travel motor, a hydraulic pump, a merging/diverging valve and a travel switching unit. The merging/diverging valve is configured to switch between merging and separating a first hydraulic circuit and a second hydraulic circuit. The travel switching unit is configured to switch between a state where sharp turning takes place as a result of one of the right-travel motor and the left-travel motor being stopped and the other being driven, with the merging/diverging valve being in a merging state, and a state where gentle turning takes place as a result of the right-travel motor and the left-travel motor being driven at different rotational speeds, with the merging/diverging valve being in a diverging state.

Abstract: Disclosed is a control device of a hydraulically driven fan. The control device of a hydraulically driven fan is characterized by comprising first command value calculation means for calculating a fan speed command by a proportional term only while a difference between a target valve controlled variable and an actual valve controlled variable is not smaller than a predetermined threshold, second command value calculation means for calculating a fan speed command by the proportional term and an integral term while a difference between a target valve controlled variable and an actual valve controlled variable is smaller than a predetermined threshold, target valve controlled variable calculation means for calculating a target valve controlled variable of a control valve based on the calculated fan speed command, and control means for outputting a valve controlled variable to a control valve such that the control valve reaches the target valve controlled variable.

Abstract: A hydraulic pressure control apparatus may include an oil tank, a first hydraulic pump receiving oil from the oil tank generating a low pressure, a second hydraulic pump receiving the low pressure and generating a high pressure, a torque converter and a lubrication portion receiving the low pressure, a powertrain receiving the high pressure, a pump connecting line connecting the first hydraulic pump with the second hydraulic pump, a first bypass line adapted to supply hydraulic pressure from the oil tank to the second hydraulic pump by detouring around the first hydraulic pump, and a second bypass line bifurcated from the pump connecting line so as to supply hydraulic pressure to the powertrain by detouring around the second hydraulic pump, wherein the first bypass line and the second bypass line respectively include a check valve and are selectively opened/closed by operation of each check valve.

Abstract: A control system actuates at least two hydraulic consumers that may be supplied with pressure medium via a pump, in the case of which an electrically or electrohydraulically adjustable metering orifice (8) is situated in the pressure medium flow path to each of the consumers. The pressure medium flow to the consumer may be adjusted by the metering orifice. A device may adjust the pump pressure or the pumped quantity once a maximum load pressure in the supply line (22, 24) of a consumer has been reached, depending on the demand for pressure medium by one consumer or the other consumer.

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: An object of the present invention is to operate the working machine etc. with satisfactory responsiveness as intended by the operator while enhancing engine efficiency, pump efficiency, and the like, where a first engine target revolution ncom1 adapted to a current pump target discharge flow rate Qsum is set, and when determined that the current pump target discharge flow rate Qsum is greater than a predetermined flow rate (10 (L/min)), a revolution nM (e.g., 1400 rpm) greater than an engine low idle revolution nL is set as a second engine target revolution ncom2 determining that operation levers 41 to 44 switched from a non-operation state to an operation state. The engine revolution is controlled so that the second engine target revolution ncom2 is obtained if the second engine target revolution ncom2 is equal to or greater than the first engine target revolution ncom1.

Abstract: A hydraulic control system includes a source of pressurized hydraulic fluid for providing a pressurized hydraulic fluid, a main line circuit in fluid communication with the source of pressurized hydraulic fluid, a regulation valve in communication with the source of pressurized hydraulic fluid, the regulation valve moveable between a plurality of positions, and a lubrication valve in communication with the regulation valve, the lubrication valve moveable between a plurality of positions. A lubrication circuit and a cooling circuit are in communication with the lubrication valve.

Abstract: A hydraulic system including an accumulator and a hydraulic transformer is disclosed. The hydraulic transformer includes first and second variable displacement pump/motor units mounted on a rotatable shaft. The rotatable shaft has an end adapted for connection to an external load. The first variable displacement pump/motor unit includes a first side that fluidly connects to a pump and a second side that fluidly connects to a tank. The second variable displacement pump/motor unit includes a first side that fluidly connects to the accumulator and a second side that fluidly connects with the tank.

Abstract: Disclosed embodiments of power machines, implements and hydraulic systems utilize a hydraulic flow control circuit and method to implement multiple modes of operation while optimizing hydraulic fluid flow to either or both of primary and secondary function devices.

Abstract: A hydraulic two-circuit system (2, 4) for activating consumers (A1, B1; A2, B2; A3, B3) of a mobile unit, for example a track-laying unit, and an interconnecting valve arrangement (38), which is suitable for a two-circuit system (2, 4) of this type and via which the two circuits (2, 4) can be interconnected so as to add them together, are disclosed. According to the invention, the interconnecting valve arrangement has an interconnecting valve with two pressure connections (P1, P2), two LS input connections (LS1, LS2) and two LS output connections, wherein a valve body of the interconnecting valve is designed with four control surfaces, of which two control surfaces which act in one direction are acted upon by the highest load pressure (LS1) in the first circuit and by the pumping pressure (P2) in the second circuit, and the control surfaces acting in the other direction are acted upon by the highest load pressure (LS2) in the second circuit and by the pumping pressure (P1) in the first circuit.

Abstract: According to the present disclosure, a hydraulic control apparatus for construction machinery comprises: hydraulic pumps; first and second control valve units which control the flow directions of working oil discharged from the hydraulic pumps to supply the working oil to first and second work machines, respectively, and which control the degree of opening of flow channels which interconnect the first and second work machines and the hydraulic pumps, respectively; and a control unit which controls the first and second control valve units in accordance with operating signals inputted from first and second operating units.

Abstract: A hydraulic device has a first pump, a second pump, an operating state detector configured and arranged to detect an operating state, a connection switching unit configured and arranged to selectively connect the second pump to either a first hydraulic oil line or a second hydraulic oil line, and a switching controller configured to control, based on the operating state detected by the operating state detector, a switching operation of the connection switching unit. The switching controller is further configured to inhibit the switching operation of the connection of the second pump when the detected operating state is such that at least one of clutches of a multi-stage transmission and a steering device is in a state transition or at least one brake of the steering device is being operated.

Abstract: A first hydraulic circuit leads, as clutch control pressure, pressurized oil supplied from a first hydraulic pump, to a transmission control device after regulating the pressurized oil, and leads, as torque converter operation oil, pressured oil to a torque converter, and leads pressurized oil to an oil cooler. Through a second hydraulic circuit, pressurized oil from a second hydraulic pump is distributed to a circuit portion downstream of the pressure regulation valve and upstream of a safety valve and to a circuit portion downstream of the torque converter and upstream of the oil cooler. A flow control device changes a proportion of a rate of flow in the second hydraulic circuit so that a proportion of the rate of flow to the circuit portion downstream of the torque converter and upstream of the oil cooler increases as pressure at an entrance of the torque converter increases.

Abstract: A method for operating a hydraulic actuation system during a pressure sensor malfunction is provided. The hydraulic actuation system includes a pump, a reservoir, a first work-port and a second work-port, a valve system with individual orifices, a pressure sensor system, and a controller for regulating the hydraulic actuation system based on fluid flow demand and on determined pressure differences. The method includes detecting a malfunction of a pressure sensor for the first work-port, closing second and third orifices, and regulating the pump to generate fluid flow corresponding to maximum pressure generated by the pump. The method also includes assigning a value for the difference between pump pressure and the pressure of the subject work-port that is equivalent to a value within an attainable range for difference between the two pressures. Furthermore, the method includes regulating a first orifice and a fourth orifice in response to the fluid flow demand.

Abstract: A hydraulic control assembly, in particular for controlling hydraulic consumers of a mobile machine, includes a load reporting line (26) that can be subjected to the highest load pressure of a plurality of hydraulic consumers, triggered simultaneously each via a respective main control valve (38, 57), and that is connectable by an end portion (26a) to a pump regulator (25). A pressure limiting valve (50) limits the control pressure in the end portion (26a) of the load reporting line (26). The pressure limiting valve (50) is adjustable as a function of the magnitude of a pilot control signal serving to trigger a main control valve (38, 57).

Abstract: A hydraulic system for a working machine is provided in which when heavy load fine speed operation work is performed using hydraulic cylinders as hydraulic actuators, and deterioration of fuel consumption can be prevented by reducing energy loss and improving fine speed operability. A center bypass cutoff valve 41 is disposed downstream of a center bypass line 26, and pressure sensors 42, 43, a controller 44, and a solenoid valve 45 provide control such that, when operating means 16 corresponding to a boom cylinder 5 (specific hydraulic actuator) among a plurality of operating means 18-21 is operated to supply a hydraulic fluid to a cylinder chamber 5a of the boom cylinder 5 in a load retaining side, the center bypass cutoff valve 41 is actuated and a fluid delivery pressure of a first hydraulic pump 2 is increased to be higher than a load pressure of the boom cylinder 5.

Abstract: A hydraulic implement system for a machine is disclosed. The hydraulic implement system may have a boom member, a boom actuator, and a boom operator control device movable to indicate a related operator desired boom member velocity. The hydraulic implement system may also have an implement pivotally connected to the boom member, an implement actuator, and an implement operator control device movable to indicated a related operator desired implement velocity. The range of the implement operator control device may be divided into a first portion and a second portion. The hydraulic implement system may also have a controller configured to selectively limit a velocity of the implement during manipulation of the implement operator control device within the first portion such that a lift velocity of the boom member of at least 65% of the desired boom member velocity is always possible.

Abstract: A hydrostatic transmission using a hydrostatic pump, a hydrostatic motor, and a pressure compensating load sensing auxiliary pump. The hydrostatic pump is fluidly connected to the hydrostatic motor using fluid lines and a center section. The hydrostatic pump additionally has an input shaft that drives the hydrostatic pump to provide the hydrostatic motor with power. Additionally, the pressure compensating load sensing auxiliary pump is in line with the hydrostatic pump and is rotated with the input shaft. This configuration allows the input shaft to operate the power takeoff (PTO) shaft while the hydrostatic motor output shaft operates the axles of a vehicle via a differential.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a first pump with variable displacement and being load-sense controlled, and a first hydraulic circuit associated with the first pump. The hydraulic system may also have a second pump with variable displacement and being electro-hydraulically controlled, and a second hydraulic circuit associated with the second pump. The hydraulic system may further have a flow-sharing valve arrangement configured to selectively share fluid flow between the first and second hydraulic circuits.

Abstract: A power distribution system is provided having a power source configured to generate a power output. The power distribution system also has an available power module configured to determine a total available power generated by the power source. In addition, the power distribution system has one or more parasitic power request modules configured to receive a request for power from an associated parasitic device and one or more non-parasitic power request modules configured to receive a request for power from an associated non-parasitic device. The power distribution system further has a power distribution module configured to cause the distribution of power among the parasitic and non-parasitic devices. The power distributed among the non-parasitic devices is the power remaining after the parasitic devices receive their requested power.

Abstract: A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.

Abstract: For controlling supply priorities, a hydraulic system includes several loads, a pump, and a tank. One load has a first-level supply priority, and optionally a second load has a second-level supply priority subordinate to the first level. A third load has a third-level supply priority subordinate to the second level. Each load can be connected to the pump by a separate supply line. The supply lines for the first and the optional second load are connected to the pump by a common load-pressure-controlled priority valve and the supply line for the third load is connected to the pump by an additional load-pressure-controlled priority valve. A first load-pressure line leading to the pump is connected to a load-pressure line of the third hydraulic load and to a second load-pressure line.

Abstract: A hydraulic control device according to the invention is of load-sensing design and serves to actuate a first hydraulic load and a second hydraulic load. Also provided are a first control valve for actuating the first hydraulic load and a second control valve for actuating the second hydraulic load. A first load signal can be measured on the basis of a load pressure with which the first hydraulic load is acted on, and a second load signal can be measured on the basis of a load pressure with which the second hydraulic load is acted on. Pressure medium from a pressure medium source can be supplied in parallel to the first control valve and to the second control valve. A load signal path can, in order to actuate an adjusting element which is assigned to the pressure medium source, be acted on with a highest presently measured load signal. A limiting device allows the second load signal to be limited to a predefined signal limit value.

Abstract: A hydraulic control system for controlling preferably at least two consumers, has a pump supplying the consumers with a pressure medium and having an adjustable pump capacity, an adjustable metering orifice assigned to each of the consumers, a power-beyond connection to which at least one power-beyond consumer is attachable, an inlet pressure scale connected downstream of the pump and provided in a pressure medium flow path between the pump and at least one of the two consumers, wherein the power-beyond connection branches off in the pressure medium flow path between the pump and the inlet pressure scale, a spring with a force acting upon the inlet pressure scale in a closing direction, an inlet having a pressure acting upon the inlet pressure scale in an opening direction, wherein the inlet pressure scale is configured so that it is actable upon in the closing direction selectively by either a highest load pressure or by a pressure that is greater than the highest load pressure.

Abstract: A hydraulic control system for controlling preferably at least two consumers, has a pump with an adjustable delivery quantity supplying pressure fluid, an adjustable metering orifice with which the consumers are each associatable, a power beyond connection to which at least one power beyond consumer is connectable, an inlet pressure governor unit situated downstream of the pump and acted on in a closing direction by a load pressure of the consumers or of the at least one power beyond consumer, the inlet pressure governor unit being provided in a pressure fluid flow path between the pump and at least one of the two consumers, while the power beyond connection branching off from a pressure fluid flow path between the pump and the inlet pressure governor unit, a tank, the inlet pressure governor unit in a spring-prestressed position closing a connection to the at least one of the two consumers and the tank, and in another position a pressure fluid connection to the tank is opened, the inlet pressure governor uni

Abstract: A hydraulic circuit includes a pump and at least a first, second and third actuator, supplied on demand by the pump via respective load pressure lines. Each actuator is connected to the pump by a respective control valve and supply line. A first, second and third supply priorities are assigned respectively to the first, second and third actuators. In order to safeguard priority of the actuators, and to control the supply priority levels, the supply lines of the second and third actuators are connected to each other via a connecting line, and a load pressure-controlled priority valve is arranged between the pump and the connecting line in the supply line to the third actuator. Also, a flow-reducer is placed in the supply line to the second actuator). The connecting line also includes a check valve which prohibits flow from the second supply line to the third supply line.

Abstract: A fluid pressure circuit that can, in either case where a first actuator that is fed from a first pump or a second actuator that is fed from a second pump is operated, by allowing feeding of the hydraulic fluid to a specific actuator from either the first or second pump, improve interlockability with the specific actuator. A control valve is incorporated with a plurality of first-group spools fed from a drive pump and a plurality of second-group spools fed from an idle pump. A solenoid selector valve unit switches a pilot line of a second-group tool controlling spool to a communicating state at the time of detection of a spool operation by a first pressure switch and switches a pilot line of a first-group tool controlling spool to a communicating state at the time of detection of a spool operation by a second pressure switch.

Abstract: A valve control unit that prevents a decline in interlocking operation performance when pilot pressure control of a plurality of pilot-operated control valves is carried out by proportional solenoid valves. First and second proportional solenoid valves include a Common Operation Table of lever operation amount/boom-up pilot pressure characteristics and are inputted with a common boom-up lever operation amount. A third proportional solenoid valve also includes the Operation Table and is inputted with a stick-in lever operation amount common to the fourth proportional solenoid valve. The fourth proportional solenoid valve includes an Operation Table of lever operation amount/stick-in pilot pressure characteristics different from that of the first, second, and third proportional solenoid valves and is inputted with the stick-in lever operation amount common to the third proportional solenoid valve.

Abstract: A hydraulic system is disclosed having at least two hydraulic circuits. The disclosed system apportions flow between the two hydraulic circuits based on an assumed flow rate that is held constant in both power-limited and non-power-limited conditions.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent an energy loss of a hydraulic system by automatically reducing revolution of an engine when a working device such as a boom is not driven. The hydraulic circuit includes first to third hydraulic pumps, first to third switching valves for controlling hydraulic fluid fed to working devices, a fourth switching valve for controlling hydraulic fluid fed to left and right traveling devices, a confluence switching valve for selectively supply the hydraulic fluid from the third hydraulic pump to either the working devices on the first hydraulic pump side or the working devices on the second hydraulic pump side, a signal line for traveling devices, signal lines for working devices, and a shuttle valve for selecting any one of the signal pressure formed in the signal line for the traveling devices and the signal pressure formed in the signal lines for the working devices.

Abstract: A method of allocating hydraulic fluid between two or more actuators in a machine processes a first command intended to provide a first requested fluid flow to a steering actuator for steering the machine, and a second command intended to provide a second requested fluid flow to a non-steeling actuator, such as a lift or tilt actuator. The system modifies the first and second commands to produce modified first and second commands corresponding to modified first and second fluid flows, such that the sum of the adjusted first and second fluid flows is less than or equal to a currently available flow and the modified first fluid flow meets or exceeds the lesser of the first requested fluid flow and a threshold curve that is a function of a machine variable such as engine speed or other variable or parameter.

Abstract: An actuator control system is disclosed. The actuator control system may have a pump and at least one actuator. The actuator control system may further have an actuator valve configured to control the at least one actuator. The actuator control system may also have a pump pressure sensor configured to determine a pump pressure value and a load pressure sensor configure to determine a load pressure value. The actuator control system may additionally have a controller configured to receive the pump pressure value and the load pressure value. The controller may further be configured to compare the pump pressure value and the load pressure value, and selectively implement a primary control strategy and a secondary control strategy based on the comparison.

Abstract: Disclosed is a hydraulic system for supplying primary and auxiliary pressure medium consumers with different system pressures, which exceed the load pressure by a pre-determined control pressure differential. Primary load pressure is used to produce a first control pressure differential for operating a primary pressure medium consumer. Auxiliary load pressure is converted in an amplifying device to produce a second, higher control pressure differential for operating an auxiliary pressure medium consumer.

Abstract: An open center hydraulic system that includes a variable displacement pump having an inlet, an outlet and a sensing port, the pump configured to provide reduced fluid flow in response to a predetermined fluid pressure differential between the outlet and the sensing port. A first fluid circuit and a second fluid circuit each serve as signal lines with the pump sensing port. During operation of the second fluid circuit, reduced fluid flow from the pump outlet is achieved as a result of the sum of induced fluid pressure reductions of respective controlled pressure reduction devices approaching the predetermined pump fluid pressure differential.

Abstract: A dual mode control system for a hydraulic circuit (200) having a variable displacement pump (216) includes at least two actuators, each controlled by a respective valve. The valves are connected in series with a pressure sensor (250) measuring a pressure of fluid between the first valve (224) and the second valve (234) and relaying a signal to the electronic controller (202). The electronic controller (202) operates in a first mode, varying the displacement of the pump (216) based on a command signal operating at least one of the valves, and operates in a standby mode, varying the displacement of the pump (216) based on the signal from the sensor, when both valves are in their respective neutral positions.

Abstract: The invention discloses a hydraulic control arrangement for controlling a number of consumers, particularly of a mobile working machine. In addition to the consumers of the control arrangement, an additional consumer should be able to be connected to a power beyond port. All consumers and power beyond consumers are supplied with hydraulic fluid by a pump. An input pressure scale is provided downstream of the pump, and the greater of the load pressures of the consumers or of the at least one power beyond consumer is applied to the control port of said input pressure scale.

Abstract: The invention relates to a hydraulic control device for a priority, first hydraulic consumer and a subordinate, second hydraulic consumer, pressure medium being deliverable to the first or the second consumer via a first or a second metering diaphragm. A pressure scale which allows a constant pressure difference to be adjusted above the first metering diaphragm is mounted upstream from the first metering diaphragm. For this purpose, said pressure scale is provided with a valve piston encompassing a first control edge, by means of which a first flow area between a feeding duct and the first metering diaphragm can be controlled. A second control edge which allows a second flow area to be controlled between the feeding duct and a load signaling line is provided on the valve piston of the first pressure scale.

Abstract: An anti-saturation valve assembly (51) for use in a hydraulic system having priority (17) and auxiliary (25) load circuits, the priority circuit providing a priority load signal (19). The anti-saturation valve assembly includes a pressure sensor portion (61) which senses a decrease between pump pressure (23) and the priority load signal (19), and generates a force on a pressure reducing portion (63) to reduce, correspondingly, a pilot pressure (59): The reduced pilot pressure to a pilot valve (35) results in reduced flow to a pilot-operated main control valve (27) in the auxiliary load circuit (25), thus providing anti-saturation protection for the circuit, without throttling a main flow path and wasting substantial hydraulic power.

Abstract: A hydraulic system, and associated method of control, includes an operator input device, a source of hydraulic fluid flow, and a plurality of actuators. At least one valve associated with each actuator for controlling a flow of fluid to and from the actuator. A controller is responsive to a signal from the operator input device to calculate a hydraulic pressure to be supplied to each of the actuators. The controller controls the source of hydraulic fluid flow and the valves for powering the actuators with the calculated hydraulic pressure. The controller also monitors a sensed parameter to determine whether the actuators can be powered with the calculated hydraulic pressure, and in response to a determination that the actuators cannot be powered with the calculated hydraulic pressure, calculates a discrepancy ratio and modifies actuation of the actuators with the discrepancy ratio.

Abstract: Hydraulic transmission system for a mineral material processing plant, which transmission system comprises at least two hydraulic first motors, which are arranged to drive at least one conveyor belonging to the mineral material processing plant, at least two first directional valves connected via the first actuator channels of the directional valves to each of the first motors, a hydraulic pump arranged to transfer hydraulic fluid via the first actuator channels of the directional valves to the first motors. The system also comprises pressure sensors. The first directional valves are valves that can be adjusted by external control during the running of the processing plant and which are arranged to control the volume flow of the hydraulic fluid supplied into the first motors. The control is made on the basis of the pressure of hydraulic fluid measured by pressure sensors in the first actuator channels the directional valves.

Abstract: An array of valve sections in a hydraulic system are connected to a supply line, a tank return line, and a load sense line. One valve sections includes a control valve with a metering orifice through which fluid flows from the supply line to a valve outlet. A load sense node is coupled by a load sense orifice to the load sense line. A load sense pressure limiter prevents pressure at the load sense node from exceeding a threshold level. A pressure compensator is connected in a fluid path between the valve outlet and one of the hydraulic actuators. The pressure compensator opens and closes the fluid path in response to pressure at the valve outlet and pressure at the load sense node, thereby governing the maximum amount of pressure that the respective valve section can apply to the hydraulic actuator.

Abstract: A pneumatic drive system (1) in which the movement of an output drive unit (7) of a pneumatic drive (2) is controlled by control valve means (25 and 26) which are connected with the working chambers (12 and 13) of the pneumatic drive (2). The control valve means (25 and 26) comprise at least one air economy setting (30) setting a choke cross section and a high power setting (29) defining a flow cross section larger than it. Actuating means (12 and 13) serve to ensure that the control valve means (25) are switched over, in a fashion dependent on the air pressure obtaining in the at least one working chamber (12 and 13) from the normally assumed air economy setting (30) into the high power setting (29), when the output drive unit (7) meets with an increased resistance to motion.