Patent US26171A successfully refreshed from Google Patents.
US3664540A
Expired / Lapsed
US
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Variable clearance thread closure
Assignee: National Forge Co
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Filing: 1970-06-11
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Granted: 1972-05-23
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Expires: 1990-06-11
Abstract
Abstract A THREAD SYSTEM FOR USE ON SCREW TYPE CLOSURE STRUCTURES FOR HIGH PRESSURE VESSELS WHEREIN THE THREAD FORM OF EITHER THE CLOSURE PLUG OR THE PRESSURE VESSEL IS MACHINED SUCH THAT WHEN THE VESSEL IS UPRESSURIZED THE LOAD BEARING SURFACES OF THE VESSEL AND PLUG THREADS ARE SPACED APART BY DISTANCES WHICH VARY FROM A PREDETERMINED MAXIMUM BETWEEN THE INNERMOST THREADS. THE PREDETERMINED MINIMUM AT THE OUTMOST THREADS. THE VARIABLE CLEARANCE BETWEEN THE THREADS IS CALCULATED SO AS TO ENABLE THE OUTER THREADS TO DEFLECT AS LEVERS IN ORDER THAT ALL OF THE THREADS ARE UNIFORMLY STRESSED WHEN THE VESSEL IS PRESSURIZED.
Inventors
- 👤 Donald E Witkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:10
CPC Classifications
F; F16; F16B; F16B33/00; F16B33/02; B; B65; B65D; B65D39/00; B65D39/08; F16J; F16J13/00; F16J13/02; F16J13/12; Y; Y10; Y10S; Y10S411/00; Y10S411/917
Claims Analysis
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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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |