Hitachi Construction Machinery Co., Ltd.

Hideaki Itou

Hidefumi Ishimoto

Teppei Saitoh

Ryu Narikawa

Akihiko Yamamoto

Kouji Fujita

Tadashi Nishizawa

Mitsuhiro Yoshimoto

Sakurako Hirano

Masaki Takao

Yousuke Inatsu

Provided is a work machine that allows assisting a loading work without giving uncomfortable feeling to an operator. The control deviceof the work machineincludes an allowable range calculation sectionthat calculates an allowable range indicating a range in which the front work deviceis movable in a height direction allowed in a swing operation; an operation determining sectionthat determines whether the work machineis under a convey operation; and an operation control sectionthat controls a turn operation of a boomsuch that the position of the front work devicein the height direction remains within the allowable range when the work machineis determined to be under the convey operation.

Work machine

A work machine includes a second pilot line that introduces a hydraulic fluid from a pilot hydraulic fluid source to a pilot valve bypassing a first gate lock valve, a second gate lock valve that is disposed on the second pilot line and that is configured to be switched to an open position for allowing the supply of the hydraulic fluid to the pilot valve or a closed position for interrupting the supply of the hydraulic fluid, and a controller that controls the second gate lock valve on the basis of a second remote operation signal transmitted from a remote operation apparatus and that controls the pilot valve according to a first remote operation signal transmitted from the remote operation apparatus. In a state where the first gate lock valve is at a closed position, the second gate lock valve is allowed to be controlled by the controller when stairs are in a retracted state, and is kept at the closed position irrespective of the second remote operation signal when the stairs are in an extended state.

A pilot valve assembly comprised of a pilot valve proper employing a spool to be displaced in a valve casing to bring a hydraulic pressure port and an output port into and out of communication with each other, an operation means having an operating lever with a cam member attached thereto, a pivoting shaft erected on an end plate of the pilot valve proper and connected with the manual operating lever through a universal joint, and a boot of a resilient material hermetically connected between the operation means and the end plate in such a way as to completely enshroud said universal joint, cam member and pusher, the end plate being detachably fixed to the mount member, and the boot having one end thereof connected to the operation means and having the other end hermetically gripped between the end plate and the mount member.

Pilot valve assembly

Growing community of inventors

Ibaraki, Japan

Hideaki Itou