Patent US1073134A successfully refreshed from Google Patents.
US4428993A
Expired / Lapsed
US
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Structural laminate with expanded wood core
Assignee: Baltek Inc
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Filing: 1982-05-11
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Granted: 1984-01-31
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Expires: 2002-05-11
Abstract
Abstract A structural sandwich laminate constituted by thin skins, such as aluminum or fiber-reinforced plastic sheets bonded to the faces of a core formed by an array of wood strips having a periodic wave formation. The wavy strips in the array are out of phase with each other and are bonded together at their contiguous troughs and peaks to define an open-celled expanded wood structure whereby the laminate, though light-weight, has high strength.
Inventors
- 👤 Henri A. Kohn
- 👤 Hugo Spahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:53
CPC Classifications
B; B32; B32B; B32B3/00; B32B3/10; B32B3/12; B32B21/00; B32B21/14; B32B3/26; B32B3/28; E; E04; E04C; E04C2/00; E04C2/30; E04C2/34; E04C2/36; B32B2311/00; B32B2311/24; B32B2311/30; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149; Y10T428/24157; Y10T428/31504; Y10T428/31678; Y10T428/31703
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
109 words
A structural sandwich constituted by a core of expanded wood whose faces have skins laminated thereto, said core comprising an array of wood strips die cut from a block of end grain balsa wood and having a periodic wave formation, the upper and lower edges of the strips being bonded to the skins whereby the substantially parallel fibers of the balsa wood are normal to the skins to resist compressive forces, the wavy strips in the array being out of phase with each other and being bonded together at their abutting troughs and peaks to define open-ended cells, whereby the laminate is light in weight and of high strength.
Claim 2
Dependent Claim
109 words
A structural sandwich constituted by a core of expanded wood whose faces have skins laminated thereto, said core comprising an array of wood strips die cut from a block of end grain balsa wood and having a periodic wave formation, the upper and lower edges of the strips being bonded to the skins whereby the substantially parallel fibers of the balsa wood are normal to the skins to resist compressive forces, the wavy strips in the array being out of phase with each other and being bonded together at their abutting troughs and peaks to define open-ended cells, whereby the laminate is light in weight and of high strength.
Claim 3
Dependent Claim
17 words
A structure as set forth in claim 1 wherein said skins are formed of fiber-reinforced plastic sheets.
Claim 4
Dependent Claim
19 words
A structure as set forth in claim 1 wherein said periodic wave formation is sinusoidal to produce eye-shaped cells.
Claim 5
Dependent Claim
17 words
A structure as set forth in claim 1 wherein said cells are filled with foam plastic material.
Claim 6
Dependent Claim
22 words
A structure as set forth in claim 1, wherein said wave formation is such as to create cells having a polygonal shape.
Claim 7
Dependent Claim
14 words
A structure as set forth in claim 1, wherein said skins are of steel.
Claim 8
Dependent Claim
14 words
A structure as set forth in claim 1, wherein said skins are of aluminum.
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) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |