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:
Nov. 03, 1992
Filed:
Dec. 05, 1990
Hideaki Yoshimatsu, Akashi, JP;
Koichi Fukushima, Kobe, JP;
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Abstract
A slewing control device for a hydraulic slewing crane adapted to supply a discharge oil from a hydraulic pump through a slewing control valve to a slewing motor and control a rotational direction and a rotational speed of the slewing motor. The slewing control device includes a brake pressure control valve for variably controlling a discharge pressure of the slewing motor, an acceleration pressure control valve for variably controlling a suction pressure of the slewing motor, and a controller for outputting to both pressure control valves a pressure control signal to be determined according to an operational condition of the crane upon braking of a slewing body and controlling both the discharge pressure and the suction pressure of the slewing motor to control a pressure differential therebetween. Accordingly, even when a braking torque is small, the slewing body can be smoothly braked to be stopped at a target position accurately with no oscillation of a suspended load remaining.