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:
Aug. 18, 1992
Filed:
Apr. 18, 1991
Applicant:
Inventor:
Youji Nakamura, Fukuoka, JP;
Assignee:
Mitsubishi Denki K.K., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B66C / ;
U.S. Cl.
CPC ...
212149 ; 254362 ; 318261 ;
Abstract
A variable speed electric hoist includes an invertor unit for frequency-controlling the speed of rotation of a lifting motor, a brake on/off section for turning off a brake according to a command produced from the invertor unit while the invertor unit is supplying a three-phase AC current to the lifting motor. The electric hoist also includes an emergency brake turn-on section for detecting a condition that a command produced from the invertor unit is not stopped after a lifting/lowering command is stopped to thereby turn on the brake upon detection of the condition.