Automatic door operator
Abstract
Abstract AN AUTOMATIC DOOR OPERATOR FOR A DOOR MOUNTED UPON A DOOR FRAME FOR SLIDING MOVEMENT IN A CERTICAL PLANE BETWEEN OPEN AND CLOSED POSITIONS INCLUDES A DRIVE CYLINDER TO OPEN AND CLOSE THE DOOR BY MEANS OF A DRIVE PISTON SLIDABLY MOVABLE WITHIN THE DRIVE CYLINDER BETWEEN AIR INLETS LOCATED AT EACH END OF THE CYLINDER. IN RESPONSSE TO THEE MOVEMENT OR ABSENCE OF TRAFFIC ADJACENT THE DOOR, A CONTROL VALVE SUPPLIES COMPRESSED AIR TO ONE OF THE AIR INLETS AND EXHAUST THE OTHER AIR INLET SO THAT THE DRIVE PISTON IS MOVED TOWARD THE OTHER AIR INLET, AND THE DOOR IS ADVANCED TOWARD ITS OPEN OR CLOSED POSITION. AS THE DOOR NEARS EITHER OF ITS POSITIONS, A CUSHION ASSIST SWITCH IS MAINTAINED IN AN OPERATIVE CONDITION FOR A SHORT PERIOD OF TIME, DURING WHICH TIME THE CONTROL VALVE REVERSES THE AIR FLOW IN THE DRIVE CYLINDER TO ASSIST IN BRINGING THE DOOR TO A GENTLE STOP AT ITS OPEN OR CLOSED POSITION.
Inventors
- 👤 Thomas H Crocker
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |