Abstract: A hydraulic power generation system which is monitored and controlled by means of a computer, with the ability to have said hydraulic power generation system's hydraulic characteristics and computer easily modified so as be completely customizeable, both in terms of operation and interface.

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: A control system for controlling hydraulic work attachments is provided. The system includes a hydraulic work attachment having an electronic information storage device capable of storing operational information of the attachment. When engaged with a work vehicle, this information is electronically transmitted to the vehicle's control computer so as to allow the computer to better control the work attachment. A control system for controlling multiple attachments having electronic storage devices and/or conventional work attachments is also provided.

Abstract: The pneumatic power system of this invention is a process that measures at very high resolution the pressure and/or rate of flow profile at various points throughout the pneumatic circuitry of a piece of pneumatic equipment in a manufacturing environment. Candidates for this process must use compressed air to move, lift, convey, actuate or otherwise influence the manufacturing process. The signature profile allows for high resolution measurement and recording of pressure and/or rate of flow changes throughout the process when the equipment is fully adjusted and tuned to produce product at maximum efficiency and quality. Once optimum adjustments are obtained, the pneumatic profiling process records the pressure profiles throughout the system and uses the model profile as a benchmark to compare all subsequent profile data.

Abstract: An automatic transmission for automobiles is disclosed. In the automatic transmission, a housing (1) is filled with transmission fluid. A pump (2), having an input shaft (6), is positioned at one side within the housing (1), while a turbine (3), having an output shaft (7), is positioned at the other side within the housing (1) while being opposed to the pump (2). Pluralities of turbine blades (3a), regularly arranged around the turbine (3), are changeable in their inclination angles relative to the axis of the output shaft (7) so as to allow the rotating speed to be changeable. A hydraulic pressure control unit controls the inflow and out flow of the transmission fluid for the housing (1) while controlling the hydraulic pressure within the housing. An air control valve (5) controls the inflow and outflow of air relative to the housing (1) in response to the inflow and outflow of the transmission fluid relative to the housing (1).

Abstract: Provided is a force-controlled hydro-elastic actuator, including a hydraulic actuator, having a connection to hydraulic fluid and including a mechanical displacement member positioned to be mechanically displaced by fluid flow at the actuator. A valve is connected at the hydraulic actuator connection and has a port for input and output of fluid to and from the valve. At least one elastic element is provided in series with the mechanical displacement member of the hydraulic actuator and is positioned to deliver, to a load, force generated by the hydraulic actuator. A transducer is positioned to measure a physical parameter indicative of the force delivered by the elastic element and to generate a corresponding transducer signal. A force controller is connected between the transducer and the valve to control the valve, based on the transducer signal, for correspondingly actuating the hydraulic actuator and deflecting the elastic element.

Abstract: A hydraulic system controls the flow of fluid to and from several functions on a machine. Each function has a valve assembly through which fluid is supplied under pressure from a source to an actuator and through which fluid returns from the actuator to a shared return line connected by a return line metering valve to the system tank. There are several regeneration modes of operation in which fluid exhausted from one port is supplied into the other port of the same actuator, which eliminates or reduces the amount of hydraulic fluid that must be supplied from the source. In some regeneration modes, input fluid for an actuator is obtained from another hydraulic function via the shared return line. In these regeneration modes an electronic controller operates the return line metering valve to restrict fluid from flowing into the tank from the shared return line, so that the fluid will be available to be supplied into an actuator port.

Abstract: A control system for a liftcrane that utilizes a closed loop hydraulic system that utilizes feed back and feed forward control architecture to provide responsiveness normally associated with systems that do not require feedback.

Abstract: An industrial vehicle including a frame, an axle pivotally mounted on the frame, a restriction mechanism for restricting the pivotal movement of the axle, a pair of vehicle wheels rotatably supported on the axle, and a steering mechanism having a steering wheel for steering the vehicle wheels in accordance with rotation of the steering wheel. A first detecting device detects an angular position of the steering wheel. The angular position represents a steering amount of the steering wheel. A second detecting device detects a wheel angle. The wheel angle is the angle between a plane perpendicular to a rotation axis of the vehicle wheel and a line representing straight running of the vehicle. A third detecting device detects a yaw rate of the vehicle. A fourth detecting device detects a vehicle speed. A calculating mechanism calculates a plurality of variables based on the detected angular position of the steering wheel, wheel angle, yaw rate and vehicle speed.

Abstract: A hydraulic operating system has a cylinder which is actuated to raise, hold or lower a load against the force of gravity. An electromagnetic 3/2 valve connects a working chamber of the cylinder to a hydraulic reservoir when not energized, and permits flow from a pump to the working chamber when energized. A non-return valve prevents flow from the working chamber to the pump when the valve is energized. A three position switch operates an electric control unit to raise, lower or hold the load in an intermediate position. When holding in an intermediate position, the control unit constantly energizes the valve during a first period, after which the control unit intermittently energizes and deenergizes the valve so as to lower the load in stepwise fashion during a second period.

Abstract: Each attachment for a hydraulically actuated device includes a digitally coded connector which informs a control device about its identity. The control device includes a library which relates the digitally coded identity with fluid parameters of pressure and flow rate required for operation of the hydraulically operated device. The control device outputs signals which control the accelerator of an engine, and also controls pump operations to establish the fluid parameters appropriate for the hydraulically actuated device. When a second device is actuated simultaneously with the original device, the control device automatically compensates with adjusted fluid parameters to permit optimum operation of both devices at the same time.

Abstract: A valve range is suggested suitable for use in connection with the control of fluid operated equipment. It possesses a fluid manifold, which is able to be fitted with pneumatic valves, which are operated via a signal manifold electrically. The valve range is so designed that it is suitable for the combined operation or control both of pneumatic valves and also of hydraulic valves. For the control of hydraulic valves it is provided with at least one control connection, from which the respective control signals may be taken. It is in this manner that, starting with a central valve range both pneumatic and also hydraulic valves may be operated and controlled in a comparatively simple fashion.

Abstract: Disclosed is a process for operating a pressure-operated positioning tool or gripping and clamping tool and a tool itself, in which the position of at least one adjusting member is determined and the valve-actuated supply of pressure medium to the adjusting member is regulated depending on position. To take into account the elasticity of the contact elements in the target position and to exert influence after the target position has been reached in a process and in a tool of the generic type, the regulating of the valve-actuated supply of pressure medium is not only effected in a position-dependent manner, but also takes into account the pressure of the pressure medium.

Abstract: A hydraulic drive system for a construction machine comprising a hydraulic pump (1) of variable displacement type, a pump regulator (2) for controlling a delivery rate of the hydraulic pump, a plurality of hydraulic actuators (7) driven by a hydraulic fluid supplied from the hydraulic pump, a plurality of directional control valves (4A-4D) for controlling respective flows of the hydraulic fluid supplied from the hydraulic pump to the plural hydraulic actuators, a low-pressure circuit (22), a center bypass line (23) for connecting in series center bypasses of the plural directional control valves (4A-4D) to the low-pressure circuit (22), a plurality of bleeding-off restrictors (26) in the center bypass line and having their openings variable in accordance with respectively associated directional control valves, a fixed restrictor (5) disposed in the center bypass line for producing a control pressure (PZ), and a pressure sensor (8) for detecting the control pressure and outputting a corresponding electric sign

Abstract: A regenerator for a fluid power system is arranged to control flow rates while converting pressure drops accompanying resulting changes in flow rates into useful work. A gang of displacers are incorporated into a fluid flow network that also includes an array of selectable flow paths through the displacers. A control system, responsive to changes in demand for the flow of fluid, selects among the flow paths to operate the displacers in various combinations as motors, pumps, and recirculators for dividing the flow of fluid into two variably sized portions. One portion of the flow is sized to match the demand for fluid flow, and the other portion of the flow is converted into useful work.

Abstract: An hydraulic rotary device includes a rotor which is oscillatable in a cylindrical chamber to force hydraulic fluid through a bypass conduit from one side to the other of a stator mounted in the chamber. An adjustable fluid flow restrictor is mounted in the bypass conduit and is controlled by a computer to which signals representative of the pressures on either side of the rotor and the angular position of the rotor are applied to enable adjustment and control of the speed of the rotor and/or the force required to rotate the rotor in the chamber.

Abstract: A hydraulic drive traveling system has a pressure compensated low control valve connected between a hydraulic pump and a variable displacement type hydraulic motor for controlling a flow rate of the hydraulic fluid supplied to the motor. The flow rate is controlled in accordance with the delivery pressure of the pump and demanded traveling speed of the motor. When the delivery pressure of the pump is at a high level, the motor is shifted to a first capacity. When the delivery pressure of the pump is low, the motor is shifted to either the second capacity or the first capacity depending upon the demanded traveling speed.

Abstract: A hydraulic drive system has a variable displacement type pump, at least one hydraulic actuator driven by hydraulic fluid and a directional control valve for controlling a flow of the hydraulic fluid supplied to the actuator. The flow rate of the hydraulic fluid discharged from the hydraulic pump is controlled by a drive device that drives a displacement volume varying device of the hydraulic pump. A load-sensing control device controls the operation of the drive device and is responsive to a differential pressure between a discharge pressure of the hydraulic pump and a load pressure of the actuator to thereby hold the differential pressure at a setting value. The drive system further has an instruction device that instructs a change in the differential pressure between the discharge pressure of the hydraulic pump and the load pressure of the actuator. The instruction is received by a differential pressure setter capable of changing the setting value of the differential pressure.

Abstract: An apparatus for controlling a power shovel or like construction machine which assures that various control modes for performing certain operations can reliably be selected by merely activating a switch corresponding to the operation to be performed. When a certain operation is selected, a CPU and an operation panel inputs a signal indicative of the selected operation into a pump controller. The pump controller outputs a signal indicative of the magnitude of the target engine revolution number and a magnitude of composite suction torque of the pumps adapted to the selected operation to an electric governor controller and a TVC valve. In response to this signal, the governor controller controls a governor and swash plates of the pumps such that the target engine revolution number is reached and the output torque from the engine matches the composite suction torque of the pumps.

Abstract: A controller for a hydraulic fluid flow control apparatus determines a quantity necessary for loading/unloading operations according to a signal from a lever operating degree detector, and controls a variable displacement type hydraulic pump to obtain the quantity. Accordingly, unnecessary hydraulic fluid flow in the hydraulic apparatus is reduced. The controller determines when a vehicle is stopped according to a signal from a clutch ON-OFF detector or a neutral sensor, and can raise the rpm of an engine. Therefore, when the loading/unloading operations are being executed while the vehicle is stopped, there is no need to operate the accelerator pedal.

Abstract: A hydraulic control system for simultaneously driving two hydraulic loads of a production machine by means of a variable delivery pump feeding drive fluid to the two loads through separate load lines, in accordance with independently controllable programs of flow rate and pressure, the two load lines being controlled by two proportional P/Q valves, the pump being continuously adjusted for a constant pressure gradient in the load line which carries the higher pressure, the other load line having a pressure imbalance compensating device in the form of either a flow rate measuring device, a pressure balancing valve, or a displacement-to-voltage converter connected to the associated load.

Abstract: An electrohydraulic system includes a plurality of electrohydraulic devices individually controlled by microprocessor-based control electronics. The device controllers are connected in common by a bidirectional serial data bus to a master controller for coordinating operation of the various devices. Internal programming within the master controller establishes a repetitive time-sequence of windows for communications with the various device controllers for downloading control signals and parameters, and for uploading data indicative of system status and operation. The various device controllers include internal programming for operating the associated hydraulic devices as a function of control signals and parameters received from the master controller. Pseudo-devices are also connected to the bus for time-division multiplexed communication with the master controller and for performing overall system coordination and analysis.

Abstract: An electrohydraulic system which includes a plurality of electrohydraulic devices individually controlled by microprocessor-based control electronics. A central controller for coordinating operation among the various devices includes a host controller for providing low speed serial and/or parallel output of control signals, and a master controller having a low speed serial and parallel I/O port for connection to the host controller, and a high speed serial I/O port connected by a full duplex bidirectional data bus in common to all of the device controllers.

Abstract: An electrohydraulic system includes a plurality of electrohydraulic devices individually controlled by microprocessor-based control electronics. The device controllers are connected in common by a bidirectional serial data bus to a master controller for coordinating operation of the various devices. Internal programming within the master controller establishes a repetitive time-sequence of windows for communications with the various device controllers for downloading control signals and parameters, and for uploading data indicative of system status and operation. The various device controllers include internal programming for operating the associated hydraulic devices as a function of control signals and parameters received from the master controller.

Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A working vehicle having a working device mounted on a swivel base rotated by a hydraulic motor. There is provided a control system which causes the swivel base to start and stop smoothly at highest possible standard speeds which are preset for an entire swivelling range.

Abstract: A pressure regulator control system for controlling the pressure with which welding electrodes are engaged against a workpiece comprises a transducer for establishing a first regulated fluid outlet pressure proportional to the strength of an electrical signal delivered to the transducer, and a pressure regulator or booster relay for establishing a second regulated outlet fluid pressure which is a multiple of said first outlet pressure. The outlet of the pressure regulator or booster relay is then applied to the working cylinder controlling displacement of the electrodes. The control system of the preferred embodiment includes interface means for converting digital data received from a computerized control apparatus to an analog signal which is applied to the transducer.

Abstract: A controller and method are provided for controlling pneumatic presses, and similar machines. The controller comprises a gauge to measure increments of stock length passing through the press, a length recorder to set the desired piece length, and a length comparator which compares the readout of the gauge with the preset recorder piece length, and when equal, generates a stroke initiate signal. The stroke initiate signal opens an air valve portion of the pneumatic press to communicate pressurized air with the power side of an air actuated ram, which in turn converges the press platens to perform the desired press function, such as punching holes, notching, cutoff, or the like. The controller also includes a timer to measure time beginning from the stroke initiate signal, a time recorder to set the time the air valve is to remain open, and a time comparator which compares the readout of the timer with the preset valve open time, and when equal, generates a stroke halt signal.

Abstract: Manipulator apparatus is provided with an energy efficient control arrangement. The control arrangement in a point-to-point mode of operation utilizes a servo valve to selectively admit fluid from a pressurized source to one end of a cylinder. A piston is slidably mounted within the cylinder and connected to move a manipulator arm that is movable in a plurality of axes. The servo valve is closed when a predetermined arm velocity is reached and a bypass valving arrangement is opened to interconnect the ends of the cylinder. At a predetermined position of the manipulator arm, the control arrangement closes the bypass valving arrangement and the manipulator arm is decelerated as the arm approaches the desired final position.

Abstract: The preferred embodiment is directed to an oil well pumping apparatus incorporating a walking beam having a horsehead at one end which connects to the sucker rods in the oil well. The opposite end of the walking beam is supported on a fixed pivot. A hydraulic and pneumatic combination unit connects from a supporting platform to a central point on the beam to raise and lower the beam. The improved apparatus utilizes air pressure to balance the static load on the apparatus and dynamically strokes the sucker rod string by imparting a reciprocating motion through hydraulic power applied at a specified rate to raise and lower the walking beam. A pump and motor system for a closed hydraulic loop is included. Alternate preferred embodiments are disclosed. In one form, a lubricating system is incorporated. First and second alternate forms of pickoff apparatus which powers the pneumatically balanced pumping apparatus is also included.

Abstract: A hydrostatic drive with an automatic adjusting deceleration control device and method for accomplishing the same. The drive includes a prime mover, a variable displacement hydraulic pump, a hydraulic actuator for driving a load through an operating cycle of acceleration, travel, deceleration, and travel, and a control system for regulating drive operation. Sensing devices are used to sense absolute load position at the point the pump reaches minimum displacement following deceleration. This sensed value is then compared by the control system with the theoretical load position within the operating cycle at the point deceleration should be complete, and corrections are made for variations therefrom by advancing or retarding the point at which deceleration is initiated in the operating cycle.

Abstract: A drive system for construction machinery in which hydraulic circuit is provided with a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each pump being connected in closed circuit to one or a plurality of the actuators via a solenoid-operated valve or valves to drive a movable member or members connected to the actuator or respective actuators when pressurized fluid is supplied to the actuator or actuators from the pump. At least one of the selected hydraulic actuators is further connected in closed circuit through a solenoid-operated valve to at least one of the hydraulic pumps other than the hydraulic pump which is connected in closed circuit to the hydraulic actuator. The hydraulic circuit means is controlled such that timing for switching the solenoid-operated valves is controlled in conjunction with the operation of the pump so as to absorb the shock which would otherwise be produced when each actuator is rendered operative and inoperative.

Abstract: An electronic control device for hydraulic presses for making plywood and the like having electronic computer structure for developing a control for the desired hydraulic pressure having multiple input units on which at least the width, length and unit pressure may be set into the device for automatically effecting the calculation of the required hydraulic line pressure in order to apply the proper pressure upon the laminated plywood panels. The control device also anticipates maximum line pressure and cuts off the hydraulic pump(s) before the desired pressure is reached so that the inertia of the pump(s) and motor(s) will not increase the resultant line pressure above the predetermined desired pressure.

Abstract: An electro-rheological fluid damped actuator having an actuator housing w a moveable element such as a piston and rod assembly disposed within the housing. The actuator further comprises a hydraulic circuit with an electro-rheological fluid disposed in the hydraulic circuit. The hydraulic circuit and rheological fluid provides an active and variable damping force on the moveable element. The damping force is controlled by the output of an electrical circuit which creates an electric field within the hydraulic circuit. The electric field will cause the viscosity of the electro-rheological fluid which is exposed to the electric field to increase or decrease in accordance with the magnitude of the electric field. The increase in viscosity of the electro-rheological fluid as it flows through the actuator provides an active damping force on the actuator which allows a more precise control of the output motions of the actuator.