The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 27, 1999
Filed:
Jan. 26, 1998
Seigo Arai, Hiroshima, JP;
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Abstract
A hydraulic pump is driven by a first prime mover. An actuator, which is controlled by a control valve, is operated by a pressure oil fed from the hydraulic pump. A second prime mover, which is an electric motor, is provided separately from the first prime mover. A pilot pump is driven by the motor. Hydraulic oil is conducted from the pilot pump to a pilot port of the control valve through a pilot oil pipe. A remote control valve is provided in the pilot oil pipe, and change-over operation of the control valve is controlled by the remote control valve. In an on-load state, a command value for controlling the motor is set at a target current value corresponding to a normal pressure, while in an off-load state the command value is set at a target current value which is lower. By so doing, there does not occur any unnecessary power loss even in an off-load state.