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:
Jul. 12, 1988
Filed:
Jul. 09, 1987
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66C / ;
U.S. Cl.
CPC ...
212132 ; 212147 ; 212161 ;
Abstract
A crane control method in which the parcels suspended from a rope is transversely carried by a trolley, the control being performed in an accelerating, a constant velocity travel, and a decelerating period separately, wherein the control is performed during said accelerating and decelerating only by turning on and off a predetermined accelerating and decelerating forces. More particularly, the control is performed by turning on and off the limit current value of the armature current through the motor. The present invention eliminates the necessity for feedback control by which a velocity pattern is followed.