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:
Sep. 11, 1990
Filed:
Oct. 26, 1989
Applicant:
Inventor:
Elmer V Carlson, Prospect Heights, IL (US);
Assignee:
Industrial Research Products, Inc., Elk Grove Village, IL (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R / ;
U.S. Cl.
CPC ...
381189 ; 381199 ;
Abstract
An electromagnetic transducer including a diaphragm mechanically connected to an armature, a coil wound tranversely around the armature, a permanent magnet adjacent the armature, and one or more additional magnetic members completing a magnetic circuit having a plane of symmetry longitudinally bisecting the armature, has a magnetic shield formed by two high-permeability casing halves joined together along a joint plane substantially concident with the plane of symmetry.