US5371806A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loudspeaker
Assignee: Foster Electric Co Ltd
•
Filing: 1993-05-28
•
Granted: 1994-12-06
•
Expires: 2013-05-28
Abstract
Abstract A loudspeaker has two magnets disposed directly with respect to voice coils for generating a repulsion magnetic field at the voice coils, without interposition of yoke but with mutually repulsing magnetic polarities of the magnets, and a diaphragm directly coupled at inner peripheral edge substantially to the center of outer periphery of the voice coils. Driving force is transmitted highly efficiently from the voice coils to the diaphragm, and the loudspeaker can be sufficiently minimized in the thickness and weight.
Inventors
- 👤 Rintaro Kohara
- 👤 Takeshi Yoshimura
- 👤 Hidetoshi Shirakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:03
CPC Classifications
H; H04; H04R; H04R9/00; H04R9/02; H04R9/025; H04R9/04; H04R9/046; H04R9/06; H04R2209/00; H04R2209/022
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
175 words
A loudspeaker comprising a frame, a pair of magnets disposed in the center of said frame to be mutually repulsive in the magnetic polarity for forming a repulsion magnetic field in a yoke-less manner, a coil bobbin disposed closely about an outer periphery of said pair of magnets to be within said repulsion magnetic field, voice coils would on an outer periphery of said coil bobbin, means for supporting said voice coils with respect to said frame, and a diaphragm coupled directly at an inner peripheral edge substantially to the center of the outer periphery of said voice coils within the repulsion magnetic filed, wherein said voice coils comprise three coil portions, first and second portions of which correspond respectively to divided magnetic field portions of said pair of magnets and a third portion of which corresponds to a magnetic field portion between the pair of magnets, said third coil portion corresponding to the magnetic field portion between the magnets being would in a direction reverse to that of said first and second coil portions.
Claim 2
Dependent Claim
175 words
A loudspeaker comprising a frame, a pair of magnets disposed in the center of said frame to be mutually repulsive in the magnetic polarity for forming a repulsion magnetic field in a yoke-less manner, a coil bobbin disposed closely about an outer periphery of said pair of magnets to be within said repulsion magnetic field, voice coils would on an outer periphery of said coil bobbin, means for supporting said voice coils with respect to said frame, and a diaphragm coupled directly at an inner peripheral edge substantially to the center of the outer periphery of said voice coils within the repulsion magnetic filed, wherein said voice coils comprise three coil portions, first and second portions of which correspond respectively to divided magnetic field portions of said pair of magnets and a third portion of which corresponds to a magnetic field portion between the pair of magnets, said third coil portion corresponding to the magnetic field portion between the magnets being would in a direction reverse to that of said first and second coil portions.
References Cited (Backward Citations)
US3201529A
Cited
US4783824A
Cited
US4817165A
Cited
US4868882A
Cited
US5062140A
Cited
US5214710A
Cited
US5123053A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-05 | 1998-06-06 | 1998-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-05 | 2002-06-06 | 2002-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-05 | 2006-06-06 | 2006-12-06 | $7700.00 | Window Closed / Lapsed |