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. 11, 1989
Filed:
Jul. 07, 1987
Applicant:
Inventor:
Bruce S Howard, Mercer Island, WA (US);
Assignee:
The Boeing Company, Seattle, WA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01V / ;
U.S. Cl.
CPC ...
324 67 ; 324327 ; 324236 ;
Abstract
A metal body located below a metal surface layer is detected by energizing inductance coils in a bridge circuit at a frequency below 10 KHz to avoid skin effect as one of the coils is placed proximate said body. A threshold circuit determines when bridge unbalance is caused by other than the surface layer and provides positive identification of the metal body.