US3560950A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Warning signal for swinging doors
Assignee: Individual
•
Filing: 1967-03-02
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Granted: 1971-02-02
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Expires: 1987-03-02
Abstract
Abstract A WARNING SIGNAL PROVIDED ON ONE SIDE OF A SWINGABLE DOOR IS OPERABLE BY AUTOMATIC MEANS PROVIDED ON THE OTHER SIDE OF THE DOOR, TO WARN A PERSON ON THE SIGNAL SIDE OF THE PRESENCE OF A PERSON NEAR ENOUGH TO THE OTHER SIDE FOR OPENING THE SAME EVEN BEFORE THE DOOR IS ACTUALLY BEING OPENED, WHEREBY TO PREVENT ACCIDENTAL FOCIBLE CONTACT WITH THE DOOR, OPERATION OF THE SIGNAL BEING EITHER BY CASTING A SHADOW ON A LIGHT SENSITIVE PHOTO-ELECTRIC CELL OR BY A THERMAL RESPONSIVE SWITCH ON A DOOR KNOB OR DOOR PLATE.
Inventors
- 👤 Duane Peters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:54
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19
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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |