Abstract: A signal sending device 21 which stores therein proper data, such as an accelerator position and a pump output, concerning operating conditions, such as supply hydraulic pressure and flow rate, appropriate for a working attachment to be attached to the front part of a hydraulic excavator or the like is mounted on the working attachment. The body of a hydraulic excavator is provided with a controller 11 adapted to control the hydraulic sources by receiving and storing proper data sent from the signal sending device 21. The signal sending device 21 includes a ROM 31 for storing proper data for each working attachment, a CPU 32 for retrieving proper data from the ROM 31, and a data communication interface (COM) 33 for receiving command signals sent from the controller 11 of a machine body to the CPU 32 and sending to the controller 11 proper data which have been retrieved from ROM 31 by the CPU 32.

Abstract: A control method and apparatus for construction machine. A joint type arm mechanism is provided on a construction machine which is driven by a cylinder type actuator, which is itself connected to a fluid pressure circuit having a pump. The cylinder type actuator's delivery pressure is variable in response to the movement of an operation member and is operated by the delivery pressure from the pump. The delivery pressure of the pump is maintained greater than or equal to a predetermined value even when the operation member is in a neutral position for the cylinder type actuator, so that, even immediately after the movement of the arm mechanism is initiated, a response delay of the pump or an increase of the dead zone can be suppressed and the accuracy of the completed movement of a working member can be enhanced.

Abstract: A control apparatus of a construction machine, such as hydraulic excavator, includes arms supported on the construction machine body side, a working member supported by the arms and hydraulic cylinder actuators for operating the arms and the working member, for realizing a smooth variation of an instruction value to the hydraulic cylinder actuators even if the working member is operated suddenly upon starting an operation. In the control apparatus, the arm and working members are operated by driving a control member, a target moving velocity of the working member is set so that the characteristics of the arms and working member upon starting an operation and upon ending an operation as time differentiated are regarded as those before time differentiated, and the actuators are controlled based on the target moving velocity information so that the working member is operated at the target moving velocity.

Abstract: A radiator (12a) and an oil cooler (12b) are disposed separately from an engine (11) of a construction machine and cooled by a cooling fan (15). The oil cooler (12b) is located downstream from the radiator (12a) with respect to the air flow generated when the cooling fan (15) is driven in reverse. A hydraulic motor (32) is adapted to be controlled by a directional control solenoid valve (34) of a fan driving circuit (31) so that the cooling fan (15) may be stopped, rotated forward or rotated in reverse accordingly. The directional control solenoid valve (34) is adapted to be automatically switched by a control device (41) having temperature sensors (44), (45), (46).

Abstract: The present invention relates to a control apparatus for a construction machine such as a hydraulic shovel, and the control apparatus for a construction machine includes a revolving operation member for operating a construction machine revolving unit (14), a fluid pressure pump (2) and an accumulator (5) for accumulating working oil from the fluid pressure pump (2), a fluid pressure actuator (7) for driving the construction machine revolving unit (14) to revolve with the working oil from the fluid pressure pump (2) and the accumulator (5), a first control valve (8) interposed between the fluid pressure actuator (7) and the fluid pressure pump (2), a second control valve (11) for controlling an inflow condition of the fluid from the fluid pressure actuator (7) into the accumulator (5), and control means (9) including first valve control means (9a) for controlling the first control valve (8) and second valve control means (9b) for controlling the second control valve (11).

Abstract: A hydraulic circuit enables a plurality of hydraulic actuators to be locked or unlocked at the same time no matter whether control valves controlling pressurized oil feed to the hydraulic actuators are pilot-controlled or not. To this end, the circuit is provided with oil lines leading from hydraulic pumps to an oil reservoir without passing through the control valves and with first and second selector valves 20 and 24 opening or closing the oil lines.

Abstract: A hydraulic pump control system is shown that can control the absorbing torque of a hydraulic pump with respect to the engine power for driving the hydraulic pump in a well-balanced manner, and reduce a deviation of an actual revolution number from a target revolution number of the engine. A torque of hydraulic pumps during operation is estimated from a pump pressure and first and second line pressures. Based on the estimated torque, an output torque of the hydraulic pumps is controlled so that an error between a target revolution number and an actual revolution number of the engine becomes null.

Abstract: A hydraulic actuator operation controller is shown to make it possible to easily change the operation speeds of a hydraulic actuator for a control input of an operating instrument. A signal input from a control input detection device for detecting the control input of an operating lever is converted according to a logical function by a signal conversion unit. The signal conversion unit increases or decreases the signal in magnitude and outputs the converted signal to a pump control device. The pump control device outputs an instruction to a capacity change device such as an electromagnetic proportional control valve connected to a hydraulic pump. The converted signal is also provided to a valve control device for outputting an instruction to a valve opening-degree control device such as electromagnetic proportional control valves connected to a control valve.

Abstract: Cylinder drift resulting from internal leakage of a recycling circuit, which recycles oil returned from the arm cylinder of a hydraulic shovel to the hydraulic supplying end, is reduced by an hydraulic circuit which includes a recycle valve attached directly to a control valve. When working fluid is returned from a rod chamber of arm cylinder into the control valve, the recycle valve recycles a part of the working fluid through a recycle selector valve to the hydraulic supplying end. A pilot operated check valve is disposed in the oil channel that connects the rod chamber and recycle selector valve together. When extending arm cylinder of the hydraulic shovel, pilot pressure from control valve shifts a pilot selector valve in such a direction as to open pilot operated check valve. When control valve is at the neutral position, pilot selector valve is shifted back to the return position and closes pilot operated check valve so that return oil of arm cylinder is prevented from working on recycle selector valve.

Abstract: The finishing precision and uniformity of hardness of a surface finished by a construction machine, such as back-hoe, is improved by modifying the targets of a position-tracking control system based on work-load applied to the end effector of the construction machine. For example, compaction of a surface, contoured by a position-tracking, back-hoe, can be made more uniform. This is accomplished by adjusting actuator targets, otherwise controlled on the basis of positional and speed constraints, in response to a detected work load acting on the end effector. To detect work load, a hydraulic fluid pressure signal can be applied to a computer which generates target position and speed commands to the feedback system. The control circuit may be arranged to hold work load constant (generating a constant compaction force for example) or, in response to a priority signal, the circuit can give a selected weight to both the positional constraints and the work load constraints.

Abstract: A load transfer and loading device equipped with a boom, a stick, and a bucket which are pin-coupled to each other for loading a load into the bucket, and transferring and loading it onto a specified position. The load transfer and loading device includes a weighing means for calculating the weight of the load in the bucket from a load applied to a pin coupling the boom to the stick and the position of the boom and the stick in accordance with specified equations.

Abstract: A carrier vehicle having a swing table supported on an under-carriage so as to swing a full turn, and a planetary reduction gear for reducing the revolution of a drive motor and transmitting it to the swing table. The planetary reduction gear is mounted on the under-carriage under the swing table.

Abstract: A control method and a device to control construction equipment attachments include during manual operation, the pilot pressure discharged from a pilot pump is fed from a manual operation valve through an electromagnetic change valve to a main control valve. During automatic operation, the pilot pressure from an automatic-mode selecting valve is fed through an electromagnetic proportional control valve as well as the electromagnetic change valve, all of which are controlled by a controller, to a main control valve. When the operation range is restrictively set during manual operation, the pilot pressure output from the manual operation valve is fed through the electromagnetic proportional control valve as well as the electromagnetic change valve to the main control valve. Both the main control valve and the electromagnetic proportional control valve are controlled by control signals from the controller.

Abstract: A method and a device to control a bucket actuator, which controls the scooping, carrying, scraping, or digging action of the bucket, automatically switches between a bucket angle-maintaining control mode and a manual operation mode. The bucket angle-maintaining control mode, which automatically maintains a bucket angle, is used when the method determines that excavating is not being performed. The method automatically switches to the manual operation mode when the method determines, from the two parameters of bucket angle and stick movement, that excavating is being performed.

Abstract: A system for controlling the cutting operation of a hydraulic backhoe having a bucket pivotally joined to one end of an arm, the other end of which is pivotally joined to one end of a boom having another end pivotally supported on a self propelled vehicle. Hydraulic jacks are provided for pivoting the boom relative to the vehicle, the arm relative to the boom, and the bucket relative to the arm. During each cutting operation the actual bucket speed relative to the arm and the actual arm speed relative to the boom are sensed and referred to a set of fuzzy control rules for obtaining command values for controlling the boom, arm and bucket jacks. The fuzzy control rules are so determined and utilized as to enable the machine to automatically take a cut in a manner suiting the hardness or other characteristics of the soil.

Abstract: An apparatus for controlling the lifting operation comprising an operation mode selection switch which is selectively set to an ordinary operation mode or to a lifting operation mode and a hydraulic circuit isolating means. The hydraulic circuit isolating means isolates the hydraulic circuit into a running drive hydraulic circuit which feeds the pressurized fluid of one of the variable-capacity hydraulic pumps to the actuators of the running apparatuses when the operation mode selection switch is set to the lifting operation mode and a hydraulic circuit for driving the apparatus on the side of the turning body, which feeds the pressurized fluid of the other variable-capacity hydraulic pump to the actuators other than those of the running apparatuses.

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: An operation prohibiting apparatus for construction equipment of improved controllability. A cutoff bar is positioned is a first position in which the cutoff bar protrudes across the entryway to an operator cab of the construction equipment. The cutoff bar is operationally linked with a locking mechanism for a hydraulic valve system of the construction equipment so that an operating mechanism for the system is unlocked when the cutoff bar is positioned in the first protruding position. A displacement enlarging mechanism is provided between an operating knob and the cutoff bar to facilitate manual positioning of the cutoff bar. Further, the cutoff bar is provided with flexibility to prevent possible damage to the cutoff bar.

Abstract: To allow data from the joy stick type operation levers to be output to the main control section side using a minimum number of output wires, a joy stick type operating lever is provided with a sub-control section which receives signals from the joy stick and other related sources, digitizes and arranges the signals according to a present order and outputs the signals to a main control circuit.