Patent US3538944A successfully refreshed from Google Patents.
US3538944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pilot-actuated shut-off valve
Assignee: Dresser Industries Inc
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Filing: 1968-02-28
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Granted: 1970-11-10
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Expires: 1988-02-28
Abstract
No abstract record available.
Inventors
- 👤 Robert Michael Riordan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:46
CPC Classifications
F; F16; F16K; F16K17/00; F16K17/02; F16K17/168; F16K17/04; F16K17/0446; F16K17/0453; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7781; Y10T137/7783
Claims Analysis
Total Claims: 0
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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) | 1973-11-09 | 1974-05-11 | 1974-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-09 | 1978-05-11 | 1978-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-09 | 1982-05-11 | 1982-11-10 | $7700.00 | Window Closed / Lapsed |