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:
Oct. 13, 1981
Filed:
Sep. 11, 1979
Applicant:
Inventor:
Dana B Hathaway, Amesbury, MA (US);
Assignee:
Epicure Products Inc., Newburyport, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04R / ;
U.S. Cl.
CPC ...
1791 / ; 1791 / ; 181167 ;
Abstract
A loudspeaker has a focused magnetic field and a specialized voice-coil structure, which provides constant inductance at the voice coil over the entire extent of voice coil excursion. The magnetic field is focused to a thin disc and the winding of the voice coil is of a height so that it is always in view of the thin disc of the magnetic field. The voice coil winding is not more than two layers. An extended base cross-section center pole is employed having an undercut portion forming a crown at the top. The edges of the crown are chamfered to cooperate with chamfered edges on a top plate to form the thin disc of the focused magnetic field.