US3579709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Door return and check mechanism
Assignee: Individual
•
Filing: 1969-12-24
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Granted: 1971-05-25
•
Expires: 1989-12-24
Abstract
Abstract A DOOR RETURN MECHANISM INCLUDING DOOR CHECKING MEANS FOR SLOWING THE RATE OF RETURN AS THE DOOR APPROACHES ITS CLOSED POSITION. THE RETURN MECHANISM INCLUDES A COIL SPRING WHICH, IN ADDITION TO ITS DOOR RETURN FUNCTION, SERVES TO HOLD THE DOOR OPEN WHEN THE LINKAGE IS MOVED TO AN OVER-CENTER POSITION. THE CHECKING MEANS COMPRISES A DISC-TYPE BRAKE, THE BRAKE SURFACES OF WHICH ARE MAINTAINED IN FRICTIONAL ENGAGEMENT BY AN ADJUSTABLE SPRING FORCE. THE BRAKE IS MOUNTED ACROSS A PARALLEL LINKAGE WHICH IS ARRANGED TO PROVIDE A GREATER ANGULAR MOVEMENT OF THE BRAKE SURFACES AND HENCE A GREATER BRAKING EFFECT AS THE DOOR APPROACHES THE DOOR FRAME.
Inventors
- 👤 Charles G Pierie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:46
CPC Classifications
E; E05; E05F; E05F3/00; E05F3/16; E05Y; E05Y2900/00; E05Y2900/10; E05Y2900/13; E05Y2900/132
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) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |