Patent US5366919A successfully refreshed from Google Patents.
Patent US3564790A successfully refreshed from Google Patents.
US3564790A
Expired / Lapsed
US
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Collapsibly portable step and support apparatus
Assignee: E Z FOLD MOBILE STEPS Inc
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Filing: 1969-11-03
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Granted: 1971-02-23
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Expires: 1989-11-03
Abstract
Abstract COLLAPSIBLE STEPS WHICH WHEN ASSEMBLED FORM A VERY RIGID SUPPORT DUE TO A TONGUE AND RECEIVER INTERLOCKING TECHNIQUE USED TO ATTACH THE PARTS. SEVERAL EMBODIMENTS ARE SHOWN. IN ALL OF THEM, TONGUE AND RECEIVER LOCKING MEANS COMBINATIONS ARE UNIQUELY CONSTRUCTED ADJACENT THE BASE OF THE STEPS SUCH THAT THE WEIGHT OF THE STEPS KEEPS THE PIECES IN PLACE AND TOGETHER. FURTHER, A LOCKING MEANS IN THE FORM OF A RAIL PROVIDES ADDITIONAL SUPPORT TO KEEP THE PIECES IN PLACE.
Inventors
- 👤 Aldin L Rehfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:24
CPC Classifications
E; E04; E04F; E04F11/00; E04F11/18; E04F11/02; E04F11/04; E04F11/06; E04F11/1865
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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |