Hitachi Construction Machinery Co., Ltd.

Hiroshi Onoue

Hiroshi Watanabe

Toichi Hirata

Genroku Sugiyama

Eiki Izumi

Shigetaka Nakamura

Yasuo Tanaka

Osamu Tomikawa

Hiroyuki Adachi

Hideaki Tanaka

Kazuhiro Ichimura

Yusuke Kajita

Koichi Shibata

Hideo Karasawa

Kiyoshi Ono

Hidetoshi Satake

Kazunori Nakamura

Masakazu Haga

Yukio Aoyagi

Akira Tatsumi

Seiji Tamura

Gen Yasuda

Mitsuo Kihara

Hiroshi Tsukui

Hitoshi Kagiwada

Tomohiko Yasuoka

Tomohiko Yasudi

Yasushi Tanaka

Assessment information needed to calculate a used vehicle assessment value of a hydraulic excavatoris input to a portable telephoneand is then transmitted from the portable telephone. The transmitted assessment information is received at a manufacturer's base stationat a remote location. The used vehicle assessment value of the hydraulic excavatoris calculated based upon the received assessment information, and history information and operation information on the hydraulic excavatorread out from an operation information databaseand a history databasein correspondence to an ID number assigned to the hydraulic excavator which is included in the assessment information.

Construction machine management apparatus and construction machines management system

A hydraulic circuit includes a control valve that controls flow of pressure oil from a hydraulic source to work hydraulic cylinders, an operating device that issues a command for drive of the control valve, valve devices each comprising a check valve, each provided in correspondence to one of the plurality of work hydraulic cylinders to allow and prohibit outflow of pressure oil from a work hydraulic cylinder, a commanding device that outputs a command allowing or a command prohibiting extension/contraction for each of the work hydraulic cylinders and a control device that controls each of the valve devices to allow outflow of pressure oil from the work hydraulic cylinder by invalidating a check valve function in response to the command for allowing extension/contraction and to prohibit outflow of pressure oil from the work hydraulic cylinder with the check valve in response to the command for prohibiting extension/contraction.

Growing community of inventors

Ibaraki, Japan

Hiroshi Onoue