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. 21, 1989
Filed:
Sep. 10, 1987
Applicant:
Inventors:
Junichi Kimizuka, Yokohama, JP;
Yukihide Ushio, Tokyo, JP;
Kaoru Seto, Chigasaki, JP;
Kenjiro Hori, Yokohama, JP;
Toshihiko Inuyama, Fujisawa, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361100 ; 361 94 ; 361104 ; 361 89 ; 219492 ; 219501 ;
Abstract
A safety apparatus for an AC control circuit has a bidirectional thyristor, a photocoupler for detecting a load current, a transistor and a self-hold circuit for checking if a detection output from the photocoupler indicates a failure of the thyristor to commutate or lack of a trigger signal and another transistor which is turned on to blow a fuse and to cut off the load current when a failure of the thyristor to commutate or lack of the trigger signal is detected.