Patent US3131521A successfully refreshed from Google Patents.
US3131521A
Expired / Lapsed
US
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Heat sealing thermoplastic packages
Assignee: Phillips Petroleum Co
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Filing: 1961-03-23
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Granted: 1964-05-05
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Expires: 1981-03-23
Abstract
No abstract record available.
Inventors
- 👤 Doyle D Buttolph
- 👤 Jr Elmer C Beason
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:47
CPC Classifications
B; B65; B65B; B65B51/00; B65B51/10; B65B51/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2738631A
Cited
US2877121A
Cited
US2896387A
Cited
US3001348A
Cited
US2916864A
Cited
US3018594A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-05-05 | 1967-11-04 | 1968-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-05-05 | 1971-11-04 | 1972-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-05-05 | 1975-11-04 | 1976-05-05 | $7700.00 | Window Closed / Lapsed |