Abstract: It is an object of the present invention to provide a construction machine having a good engine starting property in a low temperature environment. The construction machine of the present invention includes: an electric pump having a delivery port connected to a line part of a pilot line, the line part connecting a pilot pump with a pilot control valve; a motor that drives the electric pump; and a temperature sensor that measures a temperature of a hydraulic working fluid delivered from the pilot pump. A controller starts driving of the motor in the case where a key switch is operated from a key OFF state to a key ON state and where the temperature of the hydraulic working fluid measured by the temperature sensor is lower than a predetermined temperature.

Abstract: It is an object of the present invention to provide a construction machine having a good engine starting property in a low temperature environment. The construction machine of the present invention includes: an electric pump having a delivery port connected to a line part of a pilot line, the line part connecting a pilot pump with a pilot control valve; a motor that drives the electric pump; and a temperature sensor that measures a temperature of a hydraulic working fluid delivered from the pilot pump. A controller starts driving of the motor in the case where a key switch is operated from a key OFF state to a key ON state and where the temperature of the hydraulic working fluid measured by the temperature sensor is lower than a predetermined temperature.

Abstract: The maintenance management device 3 includes an error status diagnosis unit 11, a grace period estimation unit 14, a maintenance cost estimation unit 15, and a screen display unit 17. When the error status diagnosis unit 11 has diagnosed the occurrence of an anomaly, the grace period estimation unit 14 estimates a first grace period leading up to the occurrence of a failure. The maintenance cost estimation unit 15 estimates the cost of corrective maintenance incurred when the failure occurs after the elapse of the first grace period. The screen display unit 17 displays a combination of the first grace period and the cost of corrective maintenance. Alternatively, the grace period estimation unit 14 estimates a second grace period over which preventive maintenance may be postponed without a failure.

Abstract: The operation data collection device for work machines includes a plurality of sensors attached to a work machine to receive measurement data as operation data and record the operation data in an operation data storage section. The operation data collection device further includes: a communication processing section that transmits the operation data stored in the operation data storage section to an external server in response to a download request from the external server; an access history management section that manages a download status of the operation data recorded in the operation data storage section, through the download request from the external server and the transmission of the operation data to the external server; and a recorded data change processing section that changes a condition for recording the operation data in the operation data storage section in accordance with the download status of the operation data.

Abstract: The operation data collection device for work machines includes a plurality of sensors attached to a work machine to receive measurement data as operation data and record the operation data in an operation data storage section. The operation data collection device further includes: a communication processing section that transmits the operation data stored in the operation data storage section to an external server in response to a download request from the external server; an access history management section that manages a download status of the operation data recorded in the operation data storage section, through the download request from the external server and the transmission of the operation data to the external server; and a recorded data change processing section that changes a condition for recording the operation data in the operation data storage section in accordance with the download status of the operation data.

Abstract: The maintenance management device 3 includes an error status diagnosis unit 11, a grace period estimation unit 14, a maintenance cost estimation unit 15, and a screen display unit 17. When the error status diagnosis unit 11 has diagnosed the occurrence of an anomaly, the grace period estimation unit 14 estimates a first grace period leading up to the occurrence of a failure. The maintenance cost estimation unit 15 estimates the cost of corrective maintenance incurred when the failure occurs after the elapse of the first grace period. The screen display unit 17 displays a combination of the first grace period and the cost of corrective maintenance. Alternatively, the grace period estimation unit 14 estimates a second grace period over which preventive maintenance may be postponed without a failure.

Abstract: A hydraulic drive system comprises directional flow control valves (10a-f) for selectively supplying a hydraulic fluid from a first hydraulic pump (1a, 1b), inflow control valves (201-203) disposed respectively in branch lines (150A-C) branched from a supply line (100) for supplying a hydraulic fluid delivered from a second hydraulic pump (3a, 3b) to rod pushing-side chambers (5aA, 5bA, 6A, 7A) of hydraulic cylinders, a bypass flow control valve (204) disposed in a line (104) connecting the supply line (100) and a reservoir (2), and a controller (31) for computing control variables corresponding to operation command signals from control levers (32, 33) and controlling the inflow control valves (201-203) and the bypass flow control valve (204) in accordance with the computed control variables. Thus, the number of flow control valves and the length of piping required for their connection can be reduced, and a total pressure loss can be further reduced.

Abstract: The control valve apparatus holds a seat valve member in a position seated on a valve seat to thereby prevent a backward flow even if the pressure in the inlet chamber side becomes lower than the pressure in the outlet chamber side. With a pilot control valve member is in a closed state, when the pressure in the inlet chamber is higher, a pressurized medium is introduced to the control pressure chamber via a first valve unit and is cut off from the outlet chamber by a second valve unit. When the pressure in the outlet chamber is higher, the pressurized medium is introduced to the control pressure chamber via the second valve unit and is cut off from the outlet chamber by the first valve unit.

Abstract: The control valve apparatus holds a seat valve member in a position seated on a valve seat to thereby prevent a backward flow even if the pressure in the inlet chamber side becomes lower than the pressure in the outlet chamber side. With a pilot control valve member is in a closed state, when the pressure in the inlet chamber is higher, a pressurized medium is introduced to the control pressure chamber via a first valve unit and is cut off from the outlet chamber by a second valve unit. When the pressure in the outlet chamber is higher, the pressurized medium is introduced to the control pressure chamber via the second valve unit and is cut off from the outlet chamber by the first valve unit.

Abstract: A hydraulic drive system has directional flow control valves (10a-f) for selectively supplying a hydraulic fluid, inflow control valves (201-203) disposed respectively in branch lines (150A-C) branched from a supply line (100) for supplying a hydraulic fluid to rod pushing-side chambers (5aA, 5bA, 6A, 7A) of hydraulic cylinders. A bypass flow control valve (204) is disposed in a line (104) connecting the supply line (100) and a reservoir (2). A controller (31) is provided for computing control variables corresponding to operation command signals from control levers (32, 33) and controlling the inflow control valves (201-203) and the bypass flow control valve (204) in accordance with the computed control variables. As a result, the number of flow control valves and the length of piping required for connection of the flow control valves can be further cut, and a total pressure loss can be further reduced.

Abstract: An IC device wherein a source of IC device type-distinguishing data is provided on an IC chip, and a section for drawing out the IC device type-distinguishing data is connected to said source of IC device type-distinguishing data formed on said IC chip.

Abstract: An electronic timepiece comprises an oscillator, a frequency divider for frequency dividing the output signal of the oscillator to generate 100 Hz output pulse signals, time count circuits having a plurality of counters cascade-connected to count the output pulse signals of the frequency divider, a decoder circuit for decoding the output signal of the time count circuits to generate a display signal and a display device for displaying data corresponding to the output display signal of the decoder circuit, in which a stopwatch display mode and a normal time display mode may be selected by the operation of a switch. The electronic timepiece further includes a control circuit connected between the decoder circuit and display device and adapted to inhibit normal time display data from being supplied to the display device in response to the operation of the switch which sets the electronic timepiece into the stopwatch display mode.

Abstract: An integrated driver circuit comprises a signal-generating circuit for sending forth output signals when a power source voltage is impressed thereto; a level converting means for changing the level of one of the output signals into a control signal having a voltage n-fold (n>1) larger than the power source voltage; and at least one field effect transistor arranged to be rendered conducting or non-conducting according to said control signal for selective actuation of external display means provided outside of the integrated driver circuit.

Abstract: An electronic calculator using a very small number of operative keys which comprises only four operative keys in all, that is, key for presetting a digit (0 to 9) of any order in a display section, the key for shifting the digit, the key for designating a specified mode from among a plurality of modes of calculating operation and the equal key for providing the result of calculating operation, wherein combination of these keys attains any desired type of function.

Abstract: A clock pulse generating apparatus comprises a pulse generator for generating a pulse signal of a predetermined cycle, a frequency divider including a plurality of frequency division stages for frequency dividing an output pulse from the pulse generator, a circuit for subtracting at a predetermined ratio the number of clock pulses passing through a given frequency division stage in the frequency divider, a pulse control circuit including an external operation terminal for variably adding the number of pulses passing through another frequency division stage in the frequency divider, and a timing setting circuit for imparting a pulse subtracting timing and pulse adding timing to the pulse subtracting circuit and pulse control circuit, respectively.

Abstract: This negative resistance network includes a first predetermined channel insulated gate enhancement type field effect transistor having a drain-source path connected to positive and negative input terminals on which a predetermined input voltage is impressed.