US2956636A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loudspeaker
Assignee: Individual
•
Filing: 1956-06-11
•
Granted: 1960-10-18
•
Expires: 1976-06-11
Abstract
No abstract record available.
Inventors
- 👤 Sipko L Boersma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:12
CPC Classifications
H; H04; H04R; H04R7/00; H04R7/02; H04R7/12; H04R1/00; H04R1/20; H04R1/22; H04R1/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1624357A
Cited
US1608845A
Cited
US1759556A
Cited
US1756838A
Cited
US1821529A
Cited
DE539993C
Cited
US1844605A
Cited
GB382868A
Cited
GB451754A
Cited
US2269284A
Cited
US2717047A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-10-18 | 1964-04-18 | 1964-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-10-18 | 1968-04-18 | 1968-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-10-18 | 1972-04-18 | 1972-10-18 | $7700.00 | Window Closed / Lapsed |