US3438209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Roof support assembly of the type used on the longwall face of a coal seam
Assignee: Individual
•
Filing: 1965-05-27
•
Granted: 1969-04-15
•
Expires: 1985-05-27
Abstract
No abstract record available.
Inventors
- 👤 Konrad Grebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:17
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/04; E21D23/0409; E21D23/0481
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1594921A
Cited
DE970540C
Cited
FR1091525A
Cited
US3197966A
Cited
US3169377A
Cited
US3241323A
Cited
DE1159884B
Cited
US3197965A
Cited
DE1156037B
Cited
DE1166127B
Cited
GB968117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-04-14 | 1972-10-14 | 1973-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-14 | 1976-10-14 | 1977-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-14 | 1980-10-14 | 1981-04-15 | $7700.00 | Window Closed / Lapsed |