Patent US3526820A successfully refreshed from Google Patents.
US3526820A
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US
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Quarterline stop position control circuit for power driven revolving doors utilizing two speeds
Assignee: International Steel Co
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Filing: 1968-06-14
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Granted: 1970-09-01
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Expires: 1988-06-14
Abstract
No abstract record available.
Inventors
- 👤 Amuel E Sheckells
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:51
CPC Classifications
E; E05; E05F; E05F15/00; E05F15/60; E05F15/603; E05F15/608; H; H01; H01H; H01H3/00; H01H3/02; H01H3/16; H02; H02P; H02P7/00; H02P7/03; E05Y; E05Y2900/00; E05Y2900/10; E05Y2900/13; E05Y2900/132
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2954971A
Cited
US3041480A
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US3307660A
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US3364620A
Cited
US3308912A
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US3349876A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-08-31 | 1974-03-02 | 1974-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-08-31 | 1978-03-02 | 1978-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-08-31 | 1982-03-02 | 1982-09-01 | $7700.00 | Window Closed / Lapsed |