Patent US4699242A successfully refreshed from Google Patents.
US4699242A
Expired / Lapsed
US
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Magnetic speaker
Assignee: Daikin Industries Ltd
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Filing: 1985-12-27
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Granted: 1987-10-13
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Expires: 2005-12-27
Abstract
Abstract A magnetic speaker equipped with a flat diaphragm comprising a straight-grain wood plate or a cross-grain wood plate, for instance, made of Sitka spruce having the specific gravity range from 0.25 to 0.8, presenting excellent acoustic properties, especially, suitable for low to medium frequency speakers. The flat diaphragm is treated to chemically modify hydroxyl groups contained in the wooden component. Modification may be by esterification, etherification, acetilation, formalinization, or the like to enhance acoustical characteristics.
Inventors
- 👤 Teruaki Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:05
CPC Classifications
H; H04; H04R; H04R7/00; H04R7/02; H04R7/04; H04R7/06; H04R2307/00; H04R2307/021
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
98 words
A magnetic speaker comprising: a flat diaphragm including a plurality of wood plates made of coniferous trees, including Sitka spruce, said plurality of wood plates being adhered together such that grains of said wood plates cross each other; and a ring magnet and a voice coil connected to said flat diaphragm through a coil winding bobbin and an armature, said voice coil being inserted in a small gap within said magnet for preventing vibration of said voice coil against said magnet; said wood plates being chemically modified to prevent moisture absorption thereby maintaining constant dimensions of said plates.
Claim 2
Dependent Claim
98 words
A magnetic speaker comprising: a flat diaphragm including a plurality of wood plates made of coniferous trees, including Sitka spruce, said plurality of wood plates being adhered together such that grains of said wood plates cross each other; and a ring magnet and a voice coil connected to said flat diaphragm through a coil winding bobbin and an armature, said voice coil being inserted in a small gap within said magnet for preventing vibration of said voice coil against said magnet; said wood plates being chemically modified to prevent moisture absorption thereby maintaining constant dimensions of said plates.
Claim 3
Dependent Claim
19 words
The magnetic speaker according to claim 1, wherein said flat diaphragm is covered with paint on the surface thereof.
Claim 4
Dependent Claim
77 words
A magnetic speaker comprising: a flat diaphragm including a plurality of thin wood plates, wherein each of said plurality of thin wood plates is formed with a straight-grain or a cross-grain, and has a specific gravity of 0.25 to 0.8, said plurality of wood plates being adhered together such that grains of said wood plates cross each other; said plurality of thin wood plates being chemically modified to maintain said specific gravity of 0.25 to 0.8 therein.
Claim 5
Dependent Claim
77 words
A magnetic speaker comprising: a flat diaphragm including a plurality of thin wood plates, wherein each of said plurality of thin wood plates is formed with a straight-grain or a cross-grain, and has a specific gravity of 0.25 to 0.8, said plurality of wood plates being adhered together such that grains of said wood plates cross each other; said plurality of thin wood plates being chemically modified to maintain said specific gravity of 0.25 to 0.8 therein.
Claim 6
Dependent Claim
27 words
The magnetic speaker according to claim 3, wherein said plurality of thin wood plates are comprised of coniferous trees, including Sitka spruce, or broad-leafed trees, including Zelkova.
Claim 7
Dependent Claim
23 words
The magnetic speaker according to claim 3, wherein said wood plates are chemically modified with hydroxyl groups having a wooden component contained therein.
Claim 8
Dependent Claim
14 words
The magnetic speaker according to claim 5, wherein said modification is performed by acetilation.
Claim 9
Dependent Claim
14 words
The magnetic speaker according to claim 5, wherein said modification is performed by formalinization.
Claim 10
Dependent Claim
14 words
The magnetic speaker according to claim 3, wherein said modification is performed by esterification.
Claim 11
Dependent Claim
14 words
The magnetic speaker according to claim 3, wherein said modification is performed by etherification.
Claim 12
Dependent Claim
19 words
The magnetic speaker according to claim 3, wherein said flat diagram is covered with paint on the surface thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |