Patent US4086449A successfully refreshed from Google Patents.
US4086449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loudspeaker with burning resistant diaphragm
Assignee: Panasonic Holdings Corp
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Filing: 1976-11-05
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Granted: 1978-04-25
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Expires: 1996-11-05
Abstract
Abstract The invention discloses a loudspeaker with a diaphragm made of pulp fibers treated with a chemical condensation product of an ammonium salt of a polyphosphoric acid having a high degree of condensation with polyethyleneimine. The diaphragm has burning resistance, and the deterioration of acoustic characteristics may be prevented.
Inventors
- 👤 Kazuro Takano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:33
CPC Classifications
H; H04; H04R; H04R7/00; H04R7/02; H04R7/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
87 words
In a loudspeaker with a diaphragm made of pulp fibers, the improvement comprising using as said pulp fibers, pulp fibers that have been deposited with about 30 to about 40% by weight of a mixture consisting of highly condensed water-insoluble ammonium polyphosphate having been chemically condensed by the addition of about 2 to about 3% by weight of polyethyleneimine and having been further mixed with about 5 to about 6% by weight of a neoprene series rubber latex, all percentages by weight based on said pulp fibers.
Claim 2
Dependent Claim
87 words
In a loudspeaker with a diaphragm made of pulp fibers, the improvement comprising using as said pulp fibers, pulp fibers that have been deposited with about 30 to about 40% by weight of a mixture consisting of highly condensed water-insoluble ammonium polyphosphate having been chemically condensed by the addition of about 2 to about 3% by weight of polyethyleneimine and having been further mixed with about 5 to about 6% by weight of a neoprene series rubber latex, all percentages by weight based on said pulp fibers.
References Cited (Backward Citations)
US1759387A
Cited
GB1184878A
Cited
US3565679A
Cited
US3723074A
Cited
US3989531A
Cited
US3907063A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-24 | 1981-10-24 | 1982-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-24 | 1985-10-24 | 1986-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-24 | 1989-10-24 | 1990-04-25 | $7700.00 | Window Closed / Lapsed |