Patent US3553392A successfully refreshed from Google Patents.
US3553392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrodynamic sound radiator
Assignee: Electronics Inc of Pennsylvania
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Filing: 1968-03-07
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Granted: 1971-01-05
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Expires: 1988-03-07
Abstract
Abstract A sound radiator which includes a coil driven at audible frequencies and a magnet structure having an air gap within which the coil is moveable. The coil and magnet structure are attached to a body of stabilized foam plastic, such as polystyrene, polyurethane or bonded fibrous materials which may be in block, panel or other shape.
Inventors
- 👤 Arthur Liebscher
- 👤 Nils Harry Ljungman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:56
CPC Classifications
H; H04; H04R; H04R9/00; H04R9/06; H04R9/066; H04R5/00; H04R5/02; H04R7/00; H04R7/02; H04R7/04; H04R2205/00; H04R2205/022
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
69 words
A sound radiator comprising: a wall of stabilized rigid foam of plastic material; a driver having a relatively movable driving and driven members; said wall having a continuous uninterrupted face portion with which both of said members are in secured engagement; and one of said members comprising a helical coil and the other of said members comprising magnetic members having an air gap within which said coil is movable.
Claim 2
Dependent Claim
69 words
A sound radiator comprising: a wall of stabilized rigid foam of plastic material; a driver having a relatively movable driving and driven members; said wall having a continuous uninterrupted face portion with which both of said members are in secured engagement; and one of said members comprising a helical coil and the other of said members comprising magnetic members having an air gap within which said coil is movable.
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) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |