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:
Mar. 30, 2004
Filed:
Apr. 14, 2000
Applicant:
Inventor:
C. Ronald Coffin, Topsfield, MA (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R 2/500 ;
U.S. Cl.
CPC ...
H04R 2/500 ;
Abstract
A loudspeaker having an annular speaker cone with a central orifice, a voice coil bobbin attached to the annular speaker cone and a permanent magnet for producing a magnetic field in an air gap. A dust barrier blocks the transfer of material, such as magnetically attracted dust, through the central orifice into the air gap.