Patent US3685609A successfully refreshed from Google Patents.
US3685609A
Expired / Lapsed
US
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Loudspeaker
Assignee: US Philips Corp
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Filing: 1970-09-03
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Granted: 1972-08-22
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Expires: 1990-09-03
Abstract
Abstract A loudspeaker, formed by two dish-shaped parts provided with concentric grooves and arranged opposite one another with a vibrating system at the center. The sound channel is annular and of tapered section. The greatest geometric dimension of the channel is smaller than the corresponding acoustic length.
Inventors
- 👤 Nico Valentinus Franssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:26
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
146 words
A device for converting acoustic vibrations into electrical oscillations and conversely comprising a pair of opposed dishshaped parts forming a sound channel therebetween at least one vibrating system having a diaphragm connected to said channel and located substantially centrally thereof, the largest geometrical dimension of said channel being smaller than the corresponding acoustic length, said channel having a throat located closest to said vibrating system and a mouth located most remote therefrom, the cross-sectional area of said channel increasing exponentially with axial distance from said throat to said mouth, a sequential arrangement of transverse grooves increasing in depth from said mouth toward said throat formed on the wall of at least one of said dish-shaped parts of said channel forming a sequential arrangement of acoustic sections, each of said sections having a portion substantially acting as a mass and a portion substantially acting as a compliance.
Claim 2
Independent Claim
146 words
A device for converting acoustic vibrations into electrical oscillations and conversely comprising a pair of opposed dishshaped parts forming a sound channel therebetween at least one vibrating system having a diaphragm connected to said channel and located substantially centrally thereof, the largest geometrical dimension of said channel being smaller than the corresponding acoustic length, said channel having a throat located closest to said vibrating system and a mouth located most remote therefrom, the cross-sectional area of said channel increasing exponentially with axial distance from said throat to said mouth, a sequential arrangement of transverse grooves increasing in depth from said mouth toward said throat formed on the wall of at least one of said dish-shaped parts of said channel forming a sequential arrangement of acoustic sections, each of said sections having a portion substantially acting as a mass and a portion substantially acting as a compliance.
Claim 3
Dependent Claim
46 words
The device according to claim 1 wherein both of said dish-shaped parts have a sequential arrangement of transverse grooves formed in the wall thereof, the grooved wall of one of said dish-shaped parts being a mirror image of the grooved wall of the other dish-shaped part.
Claim 4
Dependent Claim
18 words
The device according to claim 2 wherein said throat is connected to said diaphragm by an acoustic transformer.
Claim 5
Dependent Claim
43 words
The device according to claim 3 wherein the acoustic impedance at the mouth of said channel is substantially real for the larger part of the frequency range to be transmitted, and wherein the acoustic input impedance of said throat matches the vibrating system.
Claim 6
Dependent Claim
34 words
The device according to claim 3 wherein the distance between said dish-shaped parts at the mouth of said channel is substantially equal to one-half of the wavelength of the highest frequency to be transmitted.
Claim 7
Dependent Claim
29 words
The device according to claim 5 wherein the outer circumference of each of said dish-shaped parts is approximately equal to the wavelength of the lowest frequency to be transmitted.
Claim 8
Dependent Claim
17 words
The device according to claim 3 further comprising a reflector attached to one of said dish-shaped parts.
Claim 9
Dependent Claim
35 words
The device according to claim 7 wherein said reflector forms a truncated horn for obtAining satisfactory directional pattern of the sound, and further comprising a dome-shaped portion connected to the other of said dish-shaped parts.
References Cited (Backward Citations)
US1810708A
Cited
US2956636A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |