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:
Jan. 23, 2001
Filed:
May. 27, 1999
Yasutaka Tsuruga, Ryugasaki, JP;
Kenichiro Nakatani, Tsuchiura, JP;
Junya Kawamoto, Tsuchiura, JP;
Takashi Kanai, Chiba-ken, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
An engine speed control system for a construction machine is arranged in association with its hydraulic circuit, which has main pumps, a communication line through which input ports of travel-controlling directional control valves are connected with each other, and a travel-controlling communication valve arranged in the communication line. The engine speed control system is provided with pilot valves arranged in a pilot line to control traveling, pilot valves arranged in a pilot line to control booms and the like, pilot valves arranged in a pilot line to control revolving, earth moving and the like, a pressure sensor for detecting pressures in the pilot lines, another pressure sensor for detecting a pressure in the pilot line, an engine controller for performing automatic idling control or its cancellation in accordance with signals from the pressure sensors, and a signal line for changing over the travel-controlling communication line into a communicating position in response to a pressure in the pilot valve.