Patent US2168531A successfully refreshed from Google Patents.
US2168531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low density cellulose materials
Assignee: Illinois Powder Manufacturing Co
•
Filing: 1937-10-25
•
Granted: 1939-08-08
•
Expires: 1957-10-25
Abstract
No abstract record available.
Inventors
- 👤 Bruce W Manning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:06
CPC Classifications
C; C06; C06B; C06B31/00; C06B31/28; C06B31/32; C06B31/44; C06B31/46
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) | 1942-08-07 | 1943-02-06 | 1943-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-08-07 | 1947-02-06 | 1947-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-08-07 | 1951-02-06 | 1951-08-08 | $7700.00 | Window Closed / Lapsed |