Abstract: Assessment information needed to calculate a used vehicle assessment value of a hydraulic excavator 10 is input to a portable telephone 20 and is then transmitted from the portable telephone 20. The transmitted assessment information is received at a manufacturer's base station 40 at a remote location. The used vehicle assessment value of the hydraulic excavator 10 is calculated based upon the received assessment information, and history information and operation information on the hydraulic excavator 10 read out from an operation information database 43 and a history database 42 in correspondence to an ID number assigned to the hydraulic excavator which is included in the assessment information.

Abstract: Assessment information needed to calculate a used vehicle assessment value of a hydraulic excavator 10 is input to a portable telephone 20 and is then transmitted from the portable telephone 20. The transmitted assessment information is received at a manufacturer's base station 40 at a remote location. The used vehicle assessment value of the hydraulic excavator 10 is calculated based upon the received assessment information, and history information and operation information on the hydraulic excavator 10 read out from an operation information database 43 and a history database 42 in correspondence to an ID number assigned to the hydraulic excavator which is included in the assessment information.

Abstract: Assessment information needed to calculate a used vehicle assessment value of a hydraulic excavator 10 is input to a portable telephone 20 and is then transmitted from the portable telephone 20. The transmitted assessment information is received at a manufacturer's base station 40 at a remote location. The used vehicle assessment value of the hydraulic excavator 10 is calculated based upon the received assessment information, and history information and operation information on the hydraulic excavator 10 read out from an operation information database 43 and a history database 42 in correspondence to an ID number assigned to the hydraulic excavator which is included in the assessment information.

Abstract: A working machine failure diagnosis method for performing a failure diagnosis by transmitting and receiving signals through communication devices provided at a working machine and at an information management center, according to the present invention, includes: a first step in which a first signal related to a failure of the working machine is generated at the working machine and the first signal is transmitted to the information management center from the working machine via the communication devices; a second step in which, after the first signal is transmitted, the information management center generates a second signal for identifying a location of the failure based upon the first signal and the second signal is then transmitted from the information management center to the working machine via the communication devices; and a third step in which failure information corresponding to the first signal and the second signal is provided to an operator.

Abstract: A security system for a construction machine including a construction machine equipped with a body controller for storing a first password, management apparatus arranged in a location apart from the construction machine and a portable communications unit for storing a second password provided communicably with the management apparatus and the body controller. The portable communications unit, receiving the first password from the management apparatus, replaces the second password with the first password. The body controller determines whether the second password output from the portable communications unit coincides with the first password. In case these passwords coincide with each other, an engine drive signal is output. Otherwise the engine is kept inoperable. This prevents possible theft of a construction machine.

Abstract: A working machine failure diagnosis method for performing a failure diagnosis by transmitting and receiving signals through communication devices provided at a working machine and at an information management center, according to the present invention, includes: a first step in which a first signal related to a failure of the working machine is generated at the working machine and the first signal is transmitted to the information management center from the working machine via the communication devices; a second step in which, after the first signal is transmitted, the information management center generates a second signal for identifying a location of the failure based upon the first signal and the second signal is then transmitted from the information management center to the working machine via the communication devices; and a third step in which failure information corresponding to the first signal and the second signal is provided to an operator.

Abstract: Assessment information needed to calculate a used vehicle assessment value of a hydraulic excavator 10 is input to a portable telephone 20 and is then transmitted from the portable telephone 20. The transmitted assessment information is received at a manufacturer's base station 40 at a remote location. The used vehicle assessment value of the hydraulic excavator 10 is calculated based upon the received assessment information, and history information and operation information on the hydraulic excavator 10 read out from an operation information database 43 and a history database 42 in correspondence to an ID number assigned to the hydraulic excavator which is included in the assessment information.

Abstract: A security system for a construction machine including a construction machine equipped with a body controller for storing a first password, management apparatus arranged in a location apart from the construction machine and a portable communications unit for storing a second password provided communicably with the management apparatus and the body controller. The portable communications unit, receiving the first password from the management apparatus, replaces the second password with the first password. The body controller determines whether the second password output from the portable communications unit coincides with the first password. In case these passwords coincide with each other, an engine drive signal is output. Otherwise the engine is kept inoperable. This prevents possible theft of a construction machine.

Abstract: To provide a burglarproof device for a hydraulic machine which has a high degree of security against burglary, ensures high safety, and can be simply installed in a location where the device is hard to find for burglars, a solenoid valve 23 of a burglarproof device 20 is installed in a pilot primary pressure line 3 between a pilot hydraulic pump 1 and a pilot valve device 4. Unless ten numeral keys 21a of a key input device 21 are depressed in the order of the password, an unlocking electronic circuit 22K does not generate an unlock signal and the solenoid valve 23 keeps the pilot primary pressure line 3 cut off. Therefore, a pilot primary pressure from the pilot hydraulic pump 1 is shut off and, even with a manual lever 4c of the pilot valve device 4 operated, no pilot secondary pressure is produced and a main control valve 6 is kept standstill. As a result, a hydraulic cylinder 8 is not operated and the hydraulic machine is unable to move.

Abstract: In a controller (229) of a hydraulic control system for construction machines, a valve control signal calculating function (301) works such that when an operation pattern signal (A-I) for actuators (201, 202 . . . ) is outputted, it selects corresponding one of plural output patterns for an auxiliary valve control pressure stored, as a function of a differential pressure signal between a pump delivery pressure and a maximum load pressure, in relation to the operation pattern signals, followed by calculating an auxiliary valve control pressure (Pc) dependent upon the differential pressure signal based on the selected output pattern, and also selects corresponding one of plural sets of rates of change (K . . . , K . . . ) for the auxiliary valve control pressure stored in relation to the operation pattern signals, followed by combining the calculated auxiliary valve control amount with the selected set of speed changes to calculate each of valve control signals (S21-S26).

Abstract: A rotational speed control system for controlling the number of revolutions of an engine through remote control of rotation of a governor lever. This rotational speed control system includes a stepping motor for rotating the governor lever, lever position sensor switches for detecting abutment of the governor lever against stoppers, respectively, a pulse counter, and a controller. The controller is adapted to store a count value of the pulse counter as a renewable reference value when the position sensor switches are turned on, to carry out the rotational speed control of the engine and necessary preadjustments according the reference value.

Abstract: A working machine such as a hydraulic excavator is provided with a working apparatus including a boom pivotally mounted on the body of the working apparatus and a boom-cylinder hydraulic system for the working apparatus. The hydraulic system includes an actuator for moving the boom up and down and a directional selecting valve. The directional selecting valve is arranged to effect selective switching of the feed of a pressurized working fluid to and the discharge of the working fluid from with respect to the rod-side and the bottom-side hydraulic chamber. The hydraulic system further includes a device for relieving the pressure of the bottom-side hydraulic chamber of the actuator. This relieving device is connected to the bottom-side hydraulic chamber of the actuator via a hydraulic circuit. When the pressure in the bottom-side hydraulic chamber changes from rise to fall, the pressure is released to a low-pressure side of the hydraulic circuit, thereby suppressing oscillation of the boom.

Abstract: Disclosed is a remote control system which produces electric signals to be sent to a governor driving device from an operator's cabin for remote control of the governor mechanism. This remote control system essentially includes a detector for detecting the amount of control effected to the governor mechanism, and a control device which operates on detection signals from the detector and operation signals from an operating device in the operator's cabin. The control device is adapted to produce a stop signal to the driving device when the difference in control amount between two cyclic time points becomes smaller than a predetermined value, which is regarded as a limit of operation of the governor mechanism, thereby preventing impairment or damages of the governor mechanism and operating device.

Abstract: A controller having an up/down switch for changing the rotational speed of a prime mover such as an engine, an actuator such as an electric motor for driving a governor on the basis of the operation of the up/down switch so as to control the rotational speed of the prime mover. A target speed is calculated on the basis of the operation of the up/down switch, and the prime mover speed is controlled by using the calculated value. Another switch is provided to immediately shift the prime mover speed to a speed previously set as desired. This shift switch is used to control the prime mover so that the prime mover rotates at the set speed, and this speed is adjusted by operating the up/down switch.