Patent US3371901A successfully refreshed from Google Patents.
US3371901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Support
Assignee: Individual
•
Filing: 1964-08-25
•
Granted: 1968-03-05
•
Expires: 1984-08-25
Abstract
No abstract record available.
Inventors
- 👤 Karl M Groetschel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:38
CPC Classifications
E; E21; E21D; E21D15/00; E21D15/58; E21D15/585; E21D15/586; E21D23/00; E21D23/0047; E21D23/0052; E21D23/006; E21D23/0069
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
A SUPPORT DEVICE FOR SUPPORTING THE ROOF OF A MINE IN UNDERGROUND MINING OPERATION AND OF THE TYPE WHICH CAN BE USED BY ITSELF OR AS A COMPONENT OF A SUPPORT ASSEMBLY, SAID DEVICE COMPRISING, IN COMBINATION: AN EXTERNAL PROP INCLUDING A CYLINDER AND A HOLLOW PISTON DISPOSED THEREIN WHICH IS OPEN AT THE TOP; AN INNER PROPER CARRIED WITHIN SAID HOLLOW PISTON AND BEING TELESCOPICALLY MOVABLE INDEPENDENTLY OF THE HOLLOW PISTON THEREBY TO DEFINE A COAXIAL SUPPORT, SAID PROPS BEING OF APPROXIMATELY THE SAME LENGTH; INDEPENDENT CAP MEANS PROVIDED ON EACH OF SAID PROPS AND ARRANGED TO BE EFFECTIVE UPON DIFFERENT REGIONS OF THE ROOF OF A MINE; AND MEANS FOR PLACING THE PROPS UNDER THE SAME PRESSURE BY A PRESSURE MEDIUM AND IN A SEQUENCE WHICH IS SELECTABLE.
Claim 2
Dependent Claim
130 words
A SUPPORT DEVICE FOR SUPPORTING THE ROOF OF A MINE IN UNDERGROUND MINING OPERATION AND OF THE TYPE WHICH CAN BE USED BY ITSELF OR AS A COMPONENT OF A SUPPORT ASSEMBLY, SAID DEVICE COMPRISING, IN COMBINATION: AN EXTERNAL PROP INCLUDING A CYLINDER AND A HOLLOW PISTON DISPOSED THEREIN WHICH IS OPEN AT THE TOP; AN INNER PROPER CARRIED WITHIN SAID HOLLOW PISTON AND BEING TELESCOPICALLY MOVABLE INDEPENDENTLY OF THE HOLLOW PISTON THEREBY TO DEFINE A COAXIAL SUPPORT, SAID PROPS BEING OF APPROXIMATELY THE SAME LENGTH; INDEPENDENT CAP MEANS PROVIDED ON EACH OF SAID PROPS AND ARRANGED TO BE EFFECTIVE UPON DIFFERENT REGIONS OF THE ROOF OF A MINE; AND MEANS FOR PLACING THE PROPS UNDER THE SAME PRESSURE BY A PRESSURE MEDIUM AND IN A SEQUENCE WHICH IS SELECTABLE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-03-05 | 1971-09-04 | 1972-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-03-05 | 1975-09-04 | 1976-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-03-05 | 1979-09-04 | 1980-03-05 | $7700.00 | Window Closed / Lapsed |