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:
Jun. 16, 1998
Filed:
Feb. 22, 1995
Applicant:
Inventor:
Armond D Cosman, Austin, TX (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01Q / ;
U.S. Cl.
CPC ...
343788 ; 343719 ; 343787 ;
Abstract
A passive electronic marker uses a plurality of ferrite cores to increase locating range, and the cores are attached in such a manner that a slight bend of the marker at a junction between the cores does not significantly affect the markers performance. Stable locating range and tuned frequency are achieved by controlling the air gap between the cores, using specially shaped ends or a sphere which is positioned between the cores. By selecting the appropriate geometry for the core ends and winding interconnections, the first order permeability across the air gap is held constant during bending of the marker.