US 12,215,483 B2
Construction machine
Kazuyuki Ito, Kobe (JP)
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
Appl. No. 17/908,985
Filed by HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
PCT Filed Sep. 16, 2021, PCT No. PCT/JP2021/034126
§ 371(c)(1), (2) Date Sep. 2, 2022,
PCT Pub. No. WO2022/070954, PCT Pub. Date Apr. 7, 2022.
Claims priority of application No. 2020-165708 (JP), filed on Sep. 30, 2020.
Prior Publication US 2023/0098211 A1, Mar. 30, 2023
Int. Cl. E02F 9/22 (2006.01); E02F 3/32 (2006.01); E02F 3/43 (2006.01); E02F 9/26 (2006.01); G01G 19/10 (2006.01)
CPC E02F 9/2221 (2013.01) [E02F 3/32 (2013.01); E02F 3/43 (2013.01); E02F 9/26 (2013.01); G01G 19/10 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A construction machine, comprising:
a hydraulic pump driven by an engine;
a hydraulic cylinder operated by pressure oil discharged from the hydraulic pump;
a working device operated in a vertical direction by the hydraulic cylinder;
a directional control valve provided between the hydraulic pump and the hydraulic cylinder, the directional control valve being configured to control a direction and flow rate of the pressure oil to be supplied from the hydraulic pump to the hydraulic cylinder;
a pilot hydraulic pump for supplying pilot pressure oil to the directional control valve;
a solenoid valve configured to control pressure of the pilot pressure oil to be supplied from the pilot hydraulic pump to the directional control valve;
an operation lever for outputting a signal for controlling the directional control valve via the solenoid valve;
a pressure sensor configured to detect pressure of the hydraulic cylinder;
an attitude sensor configured to detect an attitude of the working device; and
a controller configured to measure a weight of a load loaded on the working device based on the pressure of the hydraulic cylinder detected by the pressure sensor and the attitude of the working device detected by the attitude sensor,
wherein
the construction machine comprises a switching device for switching whether to measure the weight of the load, and
the controller is configured to, in a case where the attitude of the working device detected by the attitude sensor satisfies a predetermined load measurement condition, the switching device is valid, and a piston of the hydraulic cylinder is positioned in a first area provided in a predetermined area at a side of a first end which is one end of the hydraulic cylinder, or in a second area provided in a predetermined area at a side of a second end which is another end of the hydraulic cylinder, limit a command current to be output to the solenoid valve to reduce magnitude thereof as the piston approaches the first end or the second end.