US3910374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low frequency structural acoustic attenuator
Assignee: Rohr Inc
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Filing: 1974-03-18
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Granted: 1975-10-07
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Expires: 1994-03-18
Abstract
Abstract A sound attenuation honeycomb sandwich wherein each cell of a first layer acts as the neck of the resonator and each cell of the second layer acts as the cavity. The purpose of the first layer is to reduce the natural frequency of the resonator by increasing the length of the neck without using a solid, thick, sheet. The skins connected to the faying edges of the first layer are perforated to provide the necessary openings for the neck to function as the stiffness element in the resonator.
Inventors
- 👤 Ian Holehouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:06
CPC Classifications
B; B32; B32B; B32B3/00; B32B3/10; B32B3/12; G; G10; G10K; G10K11/00; G10K11/16; G10K11/172; B32B3/26; B32B3/266; B32B2305/00; B32B2305/02; B32B2305/024; B32B2307/00; B32B2307/10; B32B2307/102; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
Acoustic cellular honeycomb sandwich which comprises a first sandwich layer of spaced cell honeycomb faced on the faying edges by foraminous skins, the orifices in each of said skins juxtaposed externally with respect to each of said honeycomb cells, a second layer of cellular honeycomb material the faying edges of one side thereof connected to one of said foraminous skins with the orifices of said one of said skins juxtaposed centrally with respect to said cells of said second layer, and said cells of said second layer being of greater width than the cells of said first layer.
Claim 2
Dependent Claim
98 words
Acoustic cellular honeycomb sandwich which comprises a first sandwich layer of spaced cell honeycomb faced on the faying edges by foraminous skins, the orifices in each of said skins juxtaposed externally with respect to each of said honeycomb cells, a second layer of cellular honeycomb material the faying edges of one side thereof connected to one of said foraminous skins with the orifices of said one of said skins juxtaposed centrally with respect to said cells of said second layer, and said cells of said second layer being of greater width than the cells of said first layer.
Claim 3
Dependent Claim
46 words
The sandwich as recited in claim 1 wherein the effective acoustical neck length thereof is equal to the distance between the outer faces of said skins of said first layer plus the equivalent of 16 times the radius of said orifices divided by three times pi.
Claim 4
Dependent Claim
19 words
The sandwich of claim 1 wherein said second layer other faying edges are connected to a solid, continuous skin.
Claim 5
Dependent Claim
52 words
The sandwich of claim 2 wherein the resonant frequency of said acoustical sandwich is a function of the speed of sound times the square root of pi times the radius of the orifices squared divided by the effective length of the neck times the volume of a cell of the second layer.
References Cited (Backward Citations)
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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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |