Patent US3557512A successfully refreshed from Google Patents.
US3557512A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Structural unit with x-shaped inserts
Assignee: Dow Chemical Co
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Filing: 1968-07-22
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Granted: 1971-01-26
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Expires: 1988-07-22
Abstract
Abstract AN IMPROVED INTEGRAL STRUCTURAL UNIT HAVING TOP AND BOTTOM SURFACE MEMBERS, SPACED APART BY LONGITUDINALLY EXTENDING, WEB MEMBERS FORMING HOLLOW SPACES DEFINED BY THE TOP, BOTTOM AND ADJACENT WEB MEMBERS, SAID SPACES CONTAINING A MULTIPLICITY OF SPACED-APART STRENGTHENING RIGID INSERTS. THE IMPROVED UNIT MAY BE DETACHABLY INTERLOCKED WITH OTHER SIMILAR UNITS TO FORM A RELATIVELY FLAT STRUCTURAL SURFACE PARTICULARY SUITABLE FOR HIGH IMPACT USES SUCH AS TEMPORARY AIRCRAFT LANDING STRIPS AND AERIAL DELIVERY PLATFORMS.
Inventors
- 👤 Karl F Braeuninger
- 👤 Gordon K Glaza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:08
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/30; E04C2/34; E04C2/36
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) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |