US1556620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for alternating-current motors
Assignee: Otis Elevator Co
•
Filing: 1923-11-30
•
Granted: 1925-10-13
•
Expires: 1943-11-30
Abstract
No abstract record available.
Inventors
- 👤 David L Lindquist
- 👤 Jacob D Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:51
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/16; H02P25/18; H02P25/20
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1928-10-12 | 1929-04-13 | 1929-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-10-12 | 1933-04-13 | 1933-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-10-12 | 1937-04-13 | 1937-10-13 | $7700.00 | Window Closed / Lapsed |