US3798391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Movable magnet loudspeaker
Assignee: General Electric Co
•
Filing: 1972-06-22
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Granted: 1974-03-19
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Expires: 1992-06-22
Abstract
Abstract A transducer device such as a loudspeaker or microphone has the electrical coil stationary with respect to the acoustic diaphragm. The diaphragm is actuated by a movable permanent magnet which interacts with the field of the stationary electrical coil. The preferred permanent magnet is one having a high torque-to-weight ratio with respect to an external field. The cobalt-rare earth magnets are examples of such permanent magnets.
Inventors
- 👤 R Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:46
CPC Classifications
H; H04; H04R; H04R11/00; H04R11/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
94 words
A device for converting an electrical signal into an acoustical sound output comprising a U-shaped core of magnetically permeable material, a stationary electrical coil around said core for the creation of an electromagnetic field, a pole piece mounted on each protruding end of said core, the pole pieces defining a gap between the protruding ends of said core, a resilient nonmetallic pad bridging said gap, and a movable permanent magnet positioned on said pad to interact with said electromagnetic field and move in response to the electrical field impressed upon said stationary electrical coil.
Claim 2
Independent Claim
94 words
A device for converting an electrical signal into an acoustical sound output comprising a U-shaped core of magnetically permeable material, a stationary electrical coil around said core for the creation of an electromagnetic field, a pole piece mounted on each protruding end of said core, the pole pieces defining a gap between the protruding ends of said core, a resilient nonmetallic pad bridging said gap, and a movable permanent magnet positioned on said pad to interact with said electromagnetic field and move in response to the electrical field impressed upon said stationary electrical coil.
Claim 3
Dependent Claim
16 words
A device as claimed in claim 1 wherein the permanent magnet is a cobalt-rare earth magnet.
Claim 4
Dependent Claim
15 words
A device as claimed in claim 1 wherein the permanent magnet is a cobalt-samarium magnet.
References Cited (Backward Citations)
US2110153A
Cited
US2492255A
Cited
DE1037510B
Cited
US3076062A
Cited
US3651283A
Cited
US3682715A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |