Patent US4905931A successfully refreshed from Google Patents.
US4905931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arc suppression around fasteners
Assignee: Boeing Co
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Filing: 1988-02-18
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Granted: 1990-03-06
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Expires: 2008-02-18
Abstract
Abstract A volume of gas is enclosed by a cap around a fastener that is through a composite structure on an aircraft. The gas provides spark suppression for arcing that may occur between the composite structure and the metal fastener during a lightning strike. The volume of gas is sufficiently large to absorb the energy of small, very hot particles of graphite, epoxy, etc., that may be present resulting from arcing. High-pressure gas regions between the fastener and composite member vent to the larger volume of gas and are absorbed. This provides effective spark suppression for particular areas in an aircraft, such as a fuel tank, etc.
Inventors
- 👤 James H. Covey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:55
CPC Classifications
B; B64; B64D; B64D45/00; B64D45/02; F; F16; F16B; F16B33/00; F16B33/004
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
105 words
A spark containment apparatus comprising: a first member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000° F.; a second member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000° F.; a fastener extending through said first member and into said second member for connecting said first and second members together, said fastener being electrically conductive; and an electrically insulating enclosure attached to said first member in an airtight, sealed relationship and spaced from said fastener to provide a gas-filled void between said fastener and said enclosure.
Claim 2
Dependent Claim
105 words
A spark containment apparatus comprising: a first member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000° F.; a second member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000° F.; a fastener extending through said first member and into said second member for connecting said first and second members together, said fastener being electrically conductive; and an electrically insulating enclosure attached to said first member in an airtight, sealed relationship and spaced from said fastener to provide a gas-filled void between said fastener and said enclosure.
Claim 3
Dependent Claim
27 words
The apparatus according to claim 1 wherein said gas in said void has a volume in the range of 0.15 in 3 to 0.3 in 3 .
Claim 4
Dependent Claim
16 words
The apparatus according to claim 2 wherein said gas is air at standard temperature and pressure.
Claim 5
Dependent Claim
37 words
The apparatus according to claim 1 wherein said gas in said void includes a volume such that a temperature rise of less than 2° F. will occur due to electrical arcing and according to the formula: ΔT=Q/ρVCp.
Claim 6
Dependent Claim
37 words
The apparatus according to claim 1, further including an electrically insulating enclosure attached to said second member in an airtight, sealed relationship and spaced from said fastener, providing a gas-filled void between said fastener and said enclosure.
Claim 7
Dependent Claim
21 words
The apparatus according to claim 1, further including a rubber sealant surrounding said enclosure to protect said enclosure from corrosive materials.
Claim 8
Dependent Claim
102 words
In an aircraft structure having a composite member attached to a second member with a metal fastener, a portion of said fastener extending through said composite member and projecting from a surface of said composite member, the improvement comprising: attaching an electrically insulating enclosure to said surface with an airtight seal to enclose a volume of gas surrounding said portion of said fastener to suppress electrical arcing between said composite member and said fastener, and said composite member including a material which changes phase from solid to gas at temperatures below those possibly present on an aircraft structure during a lightning strike.
Claim 9
Dependent Claim
102 words
In an aircraft structure having a composite member attached to a second member with a metal fastener, a portion of said fastener extending through said composite member and projecting from a surface of said composite member, the improvement comprising: attaching an electrically insulating enclosure to said surface with an airtight seal to enclose a volume of gas surrounding said portion of said fastener to suppress electrical arcing between said composite member and said fastener, and said composite member including a material which changes phase from solid to gas at temperatures below those possibly present on an aircraft structure during a lightning strike.
Claim 10
Dependent Claim
11 words
The apparatus according to claim 7 wherein said fastener is plastic.
Claim 11
Dependent Claim
14 words
The apparatus according to claim 7 wherein said composite member includes graphite and epoxy.
Claim 12
Dependent Claim
12 words
The apparatus according to claim 7 wherein said composite member includes fiberglass
Claim 13
Dependent Claim
14 words
The apparatus according to claim 7, further including a rubber sealant surrounding said enclosure.
Claim 14
Dependent Claim
14 words
The apparatus according to claim 7 wherein said second member is a metal member.
Claim 15
Dependent Claim
17 words
The apparatus according to claim 7 wherein said surface is inside a fuel tank of an aircraft.
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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) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |