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Title:
CONSTRUCTION MACHINE
Document Type and Number:
WIPO Patent Application WO/2023/188593
Kind Code:
A1
Abstract:
Provided is a construction machine equipped with a front working device to which an attachment is attached via a quick hitch, a directional control valve that controls the pressure oil discharged from a hydraulic pump and drives the actuator of the front working device, and an operating lever for operating the directional control valve, the construction machine comprising: a lock port connected to the lock-side oil chamber of the lock cylinder of the quick hitch; an unlock port connected to the unlock-side oil chamber of the lock cylinder; a switching valve that switches the connection destination of the lock port and the unlock port to either the hydraulic pump or a tank; a switch for operating the switching valve; a pilot-driven relief valve installed in an oil passage that connects the hydraulic pump and the switching valve; and a relief pilot pipe that connects a hydraulic pipe, which is pressurized in accordance with the operation of the operating lever, to the pressure-receiving chamber of the relief valve.

Inventors:
OKA DAISUKE (JP)
TAKAHASHI KIWAMU (JP)
TAKEBAYASHI YOSHIFUMI (JP)
Application Number:
PCT/JP2022/046416
Publication Date:
October 05, 2023
Filing Date:
December 16, 2022
Export Citation:
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Assignee:
HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD (JP)
International Classes:
E02F3/40; E02F9/24
Domestic Patent References:
WO2018158797A12018-09-07
Foreign References:
JP2007009606A2007-01-18
JP2015200104A2015-11-12
JPH11181819A1999-07-06
JP2021147757A2021-09-27
JP2018091091A2018-06-14
JP2013148175A2013-08-01
JP2015200104A2015-11-12
Attorney, Agent or Firm:
KAICHI IP (JP)
Download PDF:
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