US3336431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric furnace
Assignee: US Borax Inc
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Filing: 1965-03-22
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Granted: 1967-08-15
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Expires: 1985-03-22
Abstract
No abstract record available.
Inventors
- 👤 Biddulph Richard Hampton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:07
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/145; H05B3/62; H05B3/64
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
99 words
A FURNACE COMPRISING AN ELECTRIC-RESISTANCE HEATING ELEMENT OF SUBSTANTIALLY TUBULAR SHAPE, THE WALL OF SAID ELEMENT BEING PROVIDED WITH AT LEAST TWO LONGITUDINAL SLOTS IN AT LEAST ONE END OF SAID ELEMENT EXTENDING INWARDLY ABOUT ONE-THIRD THE LENGTH OF SAID ELEMENT, THE INTERMEDIATE SECTION OF THE WALL BEING THINNED, A NON-SLOTTED END OF SAID ELEMENT AND EACH LIMB OF SAID SLOTTED END BEING PROVIDED WITH ELECTRICAL CONTACTS, THE RESISTANCE OF SAID ELEMENT BETWEEN ELECTRICAL CONTACTS ON DIFFERENT LIMBS OF THE SAME END OF SAID ELEMENT BEING LOWER THAN THE RESISTANCE BETWEEN ELECTRICAL CONTACTS AT OPPOSITE ENDS OF SAID ELEMENT.
Claim 2
Dependent Claim
99 words
A FURNACE COMPRISING AN ELECTRIC-RESISTANCE HEATING ELEMENT OF SUBSTANTIALLY TUBULAR SHAPE, THE WALL OF SAID ELEMENT BEING PROVIDED WITH AT LEAST TWO LONGITUDINAL SLOTS IN AT LEAST ONE END OF SAID ELEMENT EXTENDING INWARDLY ABOUT ONE-THIRD THE LENGTH OF SAID ELEMENT, THE INTERMEDIATE SECTION OF THE WALL BEING THINNED, A NON-SLOTTED END OF SAID ELEMENT AND EACH LIMB OF SAID SLOTTED END BEING PROVIDED WITH ELECTRICAL CONTACTS, THE RESISTANCE OF SAID ELEMENT BETWEEN ELECTRICAL CONTACTS ON DIFFERENT LIMBS OF THE SAME END OF SAID ELEMENT BEING LOWER THAN THE RESISTANCE BETWEEN ELECTRICAL CONTACTS AT OPPOSITE ENDS OF SAID ELEMENT.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-08-14 | 1971-02-13 | 1971-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-08-14 | 1975-02-13 | 1975-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-08-14 | 1979-02-13 | 1979-08-15 | $7700.00 | Window Closed / Lapsed |