Patent US4646521A successfully refreshed from Google Patents.
US3589972A
Expired / Lapsed
US
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Hollow structure
Assignee: Woodall Industries Inc
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Filing: 1969-06-16
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Granted: 1971-06-29
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Expires: 1989-06-16
Abstract
Abstract A HOLLOW STRUCTURE HAVING AN INTEGRAL HOLLOW PLASTIC SKIN ENCLOSING A CORE MEMBER. THE PLASTIC SKIN HAS AN INTEGRAL PERIPHERAL FLANGE FREE OF MECHANICAL STRESSES, AND THE CORE MEMBER HAS A PERIPHERAL EDGE RECEIVED WITHIN THE FLANGE OF THE SKIN. THE CORE MEMBER IN ONE EMBODIMENT IS PLASTIC, FORMING AN INTEGRAL FLANGE, AND PORTIONS OF THE CORE ARE DISPLACED AND FUSED TO THE SKIN BETWEEN THE FLANGES.
Inventors
- 👤 James W Greig
- 👤 David P Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:04
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/30; E04C2/34; E04C2/3405; E04C2002/3444; E04C2002/3455; E04C2002/3472; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |