Patent US4700100A successfully refreshed from Google Patents.
US4700100A
Expired / Lapsed
US
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Flexural disk resonant cavity transducer
Assignee: Magnavox Electronic Systems Co
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Filing: 1986-09-02
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Granted: 1987-10-13
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Expires: 2006-09-02
Abstract
Abstract Omnidirectional sonic transducers suitable for underwater operation as either hydrophones (listening devices) or projectors (sonic sources) are disclosed. The transducing device has a hollow resonant cavity with at least one flexural disk mounted therein in acoustic communication with both the interior and exterior of the cavity. The cavity also has at least one aperture providing acoustic coupling between the cavity interior and exterior, and a pliant lining covering substantially the entire cavity inner surface except for flexural disk surfaces and the aperture to detune the natural cavity resonance by reducing the rigidity of the cavity inner surface, thereby improving the overall frequency response characteristics of the transducing device.
Inventors
- 👤 John C. Congdon
- 👤 Thomas A. Whitmore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:16
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0603
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
120 words
A sonic transducer for immersion and operation in a liquid medium over a range of sonic wavelengths the shortest of which exceeds the greatest dimension of the transducer comprising: a hollow generally cylindrical cavity defining sidewall; a pair of generally circular end walls disposed at opposite extremities of the sidewall to form in conjunction therewith a generally cylindrical cavity; an electromechanical transducer element centrally located in one of the end walls; a sidewall aperture for admitting liquid to the cavity and for providing sonic communication between liquid within the cavity and the surrounding liquid medium; and a pliant interface between the liquid medium within the cavity and at least a portion of the sidewall and end walls defining the cavity.
Claim 2
Dependent Claim
120 words
A sonic transducer for immersion and operation in a liquid medium over a range of sonic wavelengths the shortest of which exceeds the greatest dimension of the transducer comprising: a hollow generally cylindrical cavity defining sidewall; a pair of generally circular end walls disposed at opposite extremities of the sidewall to form in conjunction therewith a generally cylindrical cavity; an electromechanical transducer element centrally located in one of the end walls; a sidewall aperture for admitting liquid to the cavity and for providing sonic communication between liquid within the cavity and the surrounding liquid medium; and a pliant interface between the liquid medium within the cavity and at least a portion of the sidewall and end walls defining the cavity.
Claim 3
Dependent Claim
36 words
The transducer of claim 1 further comprising a second electromechanical transducer element centrally located in the other of the end walls and electrically interconnected with said electromechanical transducer to move in opposition thereto when electrically energized.
Claim 4
Dependent Claim
26 words
The transducer of claim 2 wherein both electromechanical transducer elements are acoustically coupled to both the liquid medium within the cavity and the surrounding liquid medium.
Claim 5
Dependent Claim
25 words
The transducer of claim 3 wherein the pliant interface lines substantially the entire cavity with the exception of the electromechanical transducer elements and sidewall aperture.
Claim 6
Dependent Claim
26 words
The transducer of claim 4 wherein the pliant interface comprises a layer of compressible material adhered to the inner surfaces of the sidewall and end walls.
Claim 7
Dependent Claim
36 words
The transducer of claim 5 wherein the layer of compression material has a low surface tension surface exposed to the liquid within the cavity to ensure good surface contact between the pliant interface and the liquid.
Claim 8
Dependent Claim
24 words
The transducer of claim 6 wherein the low surface tension surface comprises a metallic foil coating one side of the layer of compressible material.
Claim 9
Dependent Claim
20 words
The transducer of claim 5 wherein the layer of compressible material is a composition of cork and a rubber-like material.
Claim 10
Dependent Claim
16 words
The transducer of claim 1 further comprising a second sidewall aperture diametrically opposite said sidewall aperture.
Claim 11
Dependent Claim
17 words
The transducer of claim 1 wherein said electromechanical transducer element is a ceramic piezoelectric eletroacoustic transducer element.
Claim 12
Dependent Claim
26 words
The transducer of claim 10 wherein said electromechanical transducer element is a trilaminate structure with a metallic plate sandwiched between a pair of ceramic piezoelectric slabs.
Claim 13
Dependent Claim
20 words
The transducer of claim 11 wherein the piezoelectric slabs are poled to respond to applied voltage in a flexural mode.
Claim 14
Dependent Claim
19 words
The transducer of claim 1 wherein the cavity defining sidewall is formed of a lightweight rigid graphite composite material.
Claim 15
Dependent Claim
77 words
An omnidirectional transducer for immersion and operation in a liquid medium comprising: a hollow rigid cavity defining enclosure; an electromechanical transducer element acoustically coupled to both the exterior and the interior cavity of the enclosure; an orifice in the enclosure for admitting liquid thereto and for providing acoustic coupling between the admitted liquid in the cavity and liquid surrounding the enclosure; and a pliant lining within the enclosure for reducing the natural resonant frequency of the enclosure.
Claim 16
Dependent Claim
77 words
An omnidirectional transducer for immersion and operation in a liquid medium comprising: a hollow rigid cavity defining enclosure; an electromechanical transducer element acoustically coupled to both the exterior and the interior cavity of the enclosure; an orifice in the enclosure for admitting liquid thereto and for providing acoustic coupling between the admitted liquid in the cavity and liquid surrounding the enclosure; and a pliant lining within the enclosure for reducing the natural resonant frequency of the enclosure.
Claim 17
Dependent Claim
40 words
The transducer of claim 14 further comprising a second electromechanical transducer element acoustically coupled to both the exterior and the interior cavity of the enclosure, and electrically interconnected with said electromechanical transducer to move in opposition thereto when electrically energized.
Claim 18
Dependent Claim
24 words
The transducer of claim 15 wherein the pliant lining lines substantially the entire cavity with the exception of the electromechanical transducer elements and orifice.
Claim 19
Dependent Claim
23 words
The transducer of claim 16 wherein the pliant lining comprises a layer of compressible material adhered to the inner surfaces of the enclosure.
Claim 20
Dependent Claim
36 words
The transducer of claim 17 wherein the layer of compressible material has a low surface tension surface exposed to the liquid within the cavity to reduce the retention of air bubbles and consequent erratic transducer operation.
Claim 21
Dependent Claim
24 words
The transducer of claim 18 wherein the low surface tension surface comprises a metallic foil coating one side of the layer of compressible material.
Claim 22
Dependent Claim
20 words
The transducer of claim 17 wherein the layer of compressible material is a composition of cork and a rubber-like material.
Claim 23
Dependent Claim
17 words
The transducer of claim 14 wherein said electromechanical transducer element is a ceramic piezoelectric electroacoustic transducer element.
Claim 24
Dependent Claim
26 words
The transducer of claim 21 wherein said electromechanical transducer element is a tilaminate structure with a metallic plate sandwiched between a pair of ceramic piezoelectric slabs.
Claim 25
Dependent Claim
20 words
The transducer of claim 22 wherein the piezoelectric slabs are poled to respond to applied voltage in a flexural mode.
Claim 26
Dependent Claim
38 words
The transducer of claim 14 operable over a range of sonic wavelengths the shortest of which exceeds the greatest dimension of the transducer and is on the order of one-tenth the greatest dimension of the electromechanical transducer element.
Claim 27
Dependent Claim
56 words
An underwater electroacoustical transducing device of the Helmholtz type having a hollow resonant cavity, a transducing flexural disk in acoustic communication with both the interior and exterior of the cavity, a cavity aperture acoustically coupling the interior and exterior of the cavity, and a pliant surface extending over a substantial portion of the cavity inner surface.
Claim 28
Dependent Claim
56 words
An underwater electroacoustical transducing device of the Helmholtz type having a hollow resonant cavity, a transducing flexural disk in acoustic communication with both the interior and exterior of the cavity, a cavity aperture acoustically coupling the interior and exterior of the cavity, and a pliant surface extending over a substantial portion of the cavity inner surface.
Claim 29
Dependent Claim
28 words
The transducing device of claim 25 wherein the pliant surface lines substantially the entire inner surface of cavity with the exception of the electromechanical transducer elements and aperture.
Claim 30
Dependent Claim
24 words
The transducing device of claim 26 wherein the pliant surface comprises a layer of compressible material adhered to the inner surface of the cavity.
Claim 31
Dependent Claim
37 words
The transducing device of claim 27 wherein the layer of compressible material has a low surface tension surface exposed to the liquid within the cavity to reduce the retention of air bubbles and consequent erratic transducer operation.
Claim 32
Dependent Claim
25 words
The transducing device of claim 28 wherein the low surface tension surface comprises a metallic foil coating one side of the layer of compressible material.
Claim 33
Dependent Claim
21 words
The transducing device of claim 27 wherein the layer of compressible material is a composition of cork and a rubber-like material.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |