US4492827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Horn speaker with reduced magnetic flux leakage
Assignee: Ibuki Kogyo Co Ltd
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Filing: 1983-06-27
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Granted: 1985-01-08
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Expires: 2003-06-27
Abstract
Abstract By adding a secondary magnetic piece with a partially open magnetic circuit to the front surface of a yoke connected to a primary magnetic piece, the magnetic flux leakage from the main magnetic piece is reduced on one hand and the magnetic flux extending across a magnetic gap is intensified through formation of a favorable magnetic field. This horn speaker is particularly useful in a ship where a horn speaker as an alarm is often required to be placed near magnetically sensitive equipment such as a compass.
Inventors
- 👤 Yoshishige Shintaku
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:19
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/30; H04R9/00; H04R9/02; H04R9/025; H04R2209/00; H04R2209/022
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
175 words
A horn speaker with reduced magnetic flux leakage, comprising: a diaphragm having a voice coil wound around a tubular portion formed on the proximal end thereof; a primary magnetic piece of an annular shape; a primary yoke of an annular shape securely fixed on the front surface of the primary magnetic piece concentrically thereto; a secondary yoke of a discoidal shape securely fixed on the rear surface of the primary magnetic piece concentrically thereto; and a central pole piece extending from the front surface of the secondary yoke, defining a gap between the inner periphery of the primary yoke and the periphery of the free end of the pole piece; further comprising: a secondary magnetic piece securely fixed on the front surface of the primary yoke concentrically thereto; the primary and the secondary magnetic pieces opposing one another with the ends of a same polarity; whereby magnetic flux leakage from the primary magnetic piece is reduced and the magnetic flux extending through the gap is mutually intensified by the primary and the secondary magnetic pieces.
Claim 2
Dependent Claim
175 words
A horn speaker with reduced magnetic flux leakage, comprising: a diaphragm having a voice coil wound around a tubular portion formed on the proximal end thereof; a primary magnetic piece of an annular shape; a primary yoke of an annular shape securely fixed on the front surface of the primary magnetic piece concentrically thereto; a secondary yoke of a discoidal shape securely fixed on the rear surface of the primary magnetic piece concentrically thereto; and a central pole piece extending from the front surface of the secondary yoke, defining a gap between the inner periphery of the primary yoke and the periphery of the free end of the pole piece; further comprising: a secondary magnetic piece securely fixed on the front surface of the primary yoke concentrically thereto; the primary and the secondary magnetic pieces opposing one another with the ends of a same polarity; whereby magnetic flux leakage from the primary magnetic piece is reduced and the magnetic flux extending through the gap is mutually intensified by the primary and the secondary magnetic pieces.
Claim 3
Dependent Claim
40 words
A horn speaker according to claim 1, wherein the primary and the secondary magnetic pieces are substantially of the same material both physically and magnetically and the secondary magnetic piece is approximately half as thick as the primary magnetic piece.
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) | 1988-01-08 | 1988-07-09 | 1989-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-08 | 1992-07-09 | 1993-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-08 | 1996-07-09 | 1997-01-08 | $7700.00 | Window Closed / Lapsed |