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:
Apr. 28, 1987
Filed:
Dec. 03, 1984
Shunichi Takahashi, Saitama, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A speaker of a type having a voice coil wound to a greater length than the length of a magnetic gap into which it extends formed between a pole of a yoke and an annular plate. A magnetic flux density setting structure is provided for establishing a constant value of Bl, where B represents the density of the magnetic flux capable of linking the voice coil and l represents the effective length of the voice coil. The magnetic flux density setting structure may be formed as a tapered surface or surfaces on the pole of the yoke or by a separate tapered plate or plates attached to the annular plate. Further, a metal cap is mounted on the pole covering an upwardly facing cup-shaped body of magnetic material.