US3500444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical heating unit with an insulating refractory support
Assignee: Johns Manville Corp
•
Filing: 1968-01-16
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Granted: 1970-03-10
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Expires: 1988-01-16
Abstract
No abstract record available.
Inventors
- 👤 Walter Kasper Hesse
- 👤 Wilbur Charles Brower
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:05
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/688; B; B28; B28B; B28B23/00; F; F28; F28F; F28F21/00; F28F21/04; F28F21/045; H05B3/20; H05B3/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1831889A
Cited
US1481113A
Cited
US3047702A
Cited
US2915475A
Cited
US3155814A
Cited
US3349224A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-03-09 | 1973-09-08 | 1974-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-03-09 | 1977-09-08 | 1978-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-03-09 | 1981-09-08 | 1982-03-10 | $7700.00 | Window Closed / Lapsed |