US5377546A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-degree linear liner impedance testing device
Assignee: Grumman Corp
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Filing: 1992-01-29
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Granted: 1995-01-03
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Expires: 2012-01-29
Abstract
Abstract A device for permitting evaluation of the acoustic impedance of liner designs used to attenuate noise in engine aircraft inlet and exhaust ducts, and in particular multiple degree of freedom designs of the type which include a porous facesheet followed by a backing depth followed by successive facesheet/backing depth combinations, includes a plurality of spacers of different thicknesses for varying the backing depths, and a movable plunger with a threaded adjustment mechanism for establishing the final backing depth. Gaskets and seals are installed at various interfaces to eliminate noise leakage paths. Two attachment bolts are used to hold the plunger assembly, face sheets, and spacers together, and an alignment disc positioned on the first facesheet is used to properly align an impedance tube waveguide on facesheet.
Inventors
- 👤 Noe Arcas
- 👤 Shepard G. Kay
- 👤 Charles A. Parente
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:37
CPC Classifications
G; G01; G01H; G01H15/00; G01N; G01N29/00; G01N29/04; G01N29/11; G01N29/22; G01N29/223; G01N2291/00; G01N2291/02; G01N2291/024; G01N2291/02441; G01N2291/04; G01N2291/045
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
61 words
Apparatus for evaluation of the acoustic impedance of structural members, comprising: spacer means for separating at least two of said structural members by a predetermined distance; alignment means for aligning an impedance tube with respect to said structural members; means for acoustically sealing said apparatus device such that acoustic signals generated within said impedance tube are directed onto said structural members.
Claim 2
Dependent Claim
61 words
Apparatus for evaluation of the acoustic impedance of structural members, comprising: spacer means for separating at least two of said structural members by a predetermined distance; alignment means for aligning an impedance tube with respect to said structural members; means for acoustically sealing said apparatus device such that acoustic signals generated within said impedance tube are directed onto said structural members.
Claim 3
Dependent Claim
45 words
Apparatus as claimed in claim 1, further comprising a plunger situated a predetermined distance from said structural members on a side of said structural members opposite said impedance tube, and plunger adjustment means for adjusting the distance between said plunger member and said structural members.
Claim 4
Dependent Claim
16 words
Apparatus as claimed in claim 2, wherein said plunger adjustment means comprises a threaded adjustment member.
Claim 5
Dependent Claim
32 words
Apparatus as claimed in claim 3, wherein said plunger is constructed of an acoustically non-porous material and said structural members are acoustic liner facesheets, whereby said plunger simulates an acoustic liner backface.
Claim 6
Dependent Claim
36 words
Apparatus as claimed in claim 1 wherein said spacer means comprises a plurality of spacer members positioned between said structural members, the number and width of said spacer members determining the distance between said structural members.
Claim 7
Dependent Claim
12 words
Apparatus as claimed in claim 5, wherein said spacer members are annular.
Claim 8
Dependent Claim
22 words
Apparatus as claimed in claim 5, wherein said acoustic sealing means comprises gaskets positioned between said structural members and said spacer members.
Claim 9
Dependent Claim
26 words
Apparatus as claimed in claim 1, wherein said alignment means comprises an impedance tube alignment disc having a central aperture dimensioned to fit said impedance tube.
Claim 10
Dependent Claim
30 words
Apparatus as claimed in claim 8, further comprising a clamping member and clamping means for releasably clamping together said clamping member, structural members, spacer members, and impedance tube alignment disc.
Claim 11
Dependent Claim
16 words
Apparatus as claimed in claim 9, wherein said clamping means comprises a clamping bolt and nut.
Claim 12
Dependent Claim
20 words
Apparatus as claimed in claim 9, wherein said acoustic sealing means comprises gasket seals sandwiching each of said structural members.
Claim 13
Dependent Claim
14 words
Apparatus as claimed in claim 1, wherein said structural members are acoustic liner facesheets.
Claim 14
Dependent Claim
76 words
Apparatus for evaluation of the acoustic impedance of structural members, comprising: spacer means for separating at least two of said structural members by a predetermined distance; alignment means for aligning an impedance tube with respect to said structural members; a plunger situated a predetermined distance from said structural members on a side of said structural members opposite said impedance tube, and plunger adjustment means for adjusting the distance between said plunger member and said structural members.
Claim 15
Dependent Claim
76 words
Apparatus for evaluation of the acoustic impedance of structural members, comprising: spacer means for separating at least two of said structural members by a predetermined distance; alignment means for aligning an impedance tube with respect to said structural members; a plunger situated a predetermined distance from said structural members on a side of said structural members opposite said impedance tube, and plunger adjustment means for adjusting the distance between said plunger member and said structural members.
Claim 16
Dependent Claim
16 words
Apparatus as claimed in claim 13, wherein said plunger adjustment means comprises a threaded adjustment member.
Claim 17
Dependent Claim
33 words
Apparatus as claimed in claim 13, wherein said plunger is constructed of an acoustically non-porous material and said structural members are acoustic liner face sheets, whereby said plunger simulates an acoustic liner backface.
Claim 18
Dependent Claim
36 words
Apparatus as claimed in claim 13, wherein said spacer means comprises a plurality of spacer members positioned between said structural members, the number and width of said spacer members determining the distance between said structural members.
Claim 19
Dependent Claim
12 words
Apparatus as claimed in claim 13, wherein said spacer members are annular.
Claim 20
Dependent Claim
19 words
Apparatus as claimed in claim 13, further comprising gasket seals positioned between said structural members and said spacer members.
Claim 21
Dependent Claim
26 words
Apparatus as claimed in claim 13, wherein said alignment means comprises an impedance tube alignment disc having a central aperture dimensioned to fit said impedance tube.
Claim 22
Dependent Claim
30 words
Apparatus as claimed in claim 13, further comprising a clamping member and clamping means for releasably clamping together said clamping member, structural members, spacer members, and impedance tube alignment disc.
Claim 23
Dependent Claim
16 words
Apparatus as claimed in claim 13, wherein said clamping means comprises a clamping bolt and nut.
Claim 24
Dependent Claim
16 words
Apparatus as claimed in claim 13, further comprising gasket seals sandwiching each of said structural members.
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) | 1998-01-02 | 1998-07-04 | 1999-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-02 | 2002-07-04 | 2003-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-02 | 2006-07-04 | 2007-01-03 | $7700.00 | Window Closed / Lapsed |