Patent US3173512A successfully refreshed from Google Patents.
US3173512A
Expired / Lapsed
US
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Ladder levelling device
Assignee: Individual
•
Filing: 1962-11-19
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Granted: 1965-03-16
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Expires: 1982-11-19
Abstract
No abstract record available.
Inventors
- 👤 Sturdy Leonard Frederick
- 👤 Sturdy Hubert Thomas
- 👤 Scott Kenneth Grant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:54
CPC Classifications
E; E06; E06C; E06C7/00; E06C7/42; E06C7/44
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
139 words
A LADDER LEVELLING DEVICE COMPRISING A PAIR OF EXTENSION LEGS ADAPTED SLIDABLY TO ENGAGE OPPOSITE SIDE RAILS OF A LADDER, MANUALLY OPERABLE CLAMPING MEANS DIRECTLY AND FIXEDLY SECURABLE TO SAID LADDER, SAID CLAMPING MEANS INCLUDING A PAIR OF PLATES, A PORTION OF EACH SAID PLATE BEING SHAPED SO THAT SAID PLATES CO-OPERATE TO EMBRACE A LADDER RUNG THEREBETWEEN, A CAM MEMBER PIVOTALLY SECURED BETWEEN SAID PLATES, A FIRST FLEXIBLE MEMBER INTERCONNECTING THE UPPER PORTIONS OF SAID EXTENSION LEGS, A SECOND FLEXIBLE MEMBER INTERCONNECTING THE LOWER PORTIONS OF SAID EXTENSION LEGS, SAID FIRST AND SECOND FLEXIBLE MEMBERS PASSING THROUGH SAID CLAMPING MEANS, AND SAID CAM MEMBER IN SAID CLAMPING MEANS BEING ADAPTED TO ENGAGE SAID FLEXIBLE MEMBERS AND PREVENT MOVEMENT OF SAID FLEXIBLE MEMBERS RELATIVE TO ONE ANOTHER AND TO SAID CLAMPING MEANS UNLESS SAID CLAMPING MEANS IS MANUALLY RELEASED.
Claim 2
Dependent Claim
139 words
A LADDER LEVELLING DEVICE COMPRISING A PAIR OF EXTENSION LEGS ADAPTED SLIDABLY TO ENGAGE OPPOSITE SIDE RAILS OF A LADDER, MANUALLY OPERABLE CLAMPING MEANS DIRECTLY AND FIXEDLY SECURABLE TO SAID LADDER, SAID CLAMPING MEANS INCLUDING A PAIR OF PLATES, A PORTION OF EACH SAID PLATE BEING SHAPED SO THAT SAID PLATES CO-OPERATE TO EMBRACE A LADDER RUNG THEREBETWEEN, A CAM MEMBER PIVOTALLY SECURED BETWEEN SAID PLATES, A FIRST FLEXIBLE MEMBER INTERCONNECTING THE UPPER PORTIONS OF SAID EXTENSION LEGS, A SECOND FLEXIBLE MEMBER INTERCONNECTING THE LOWER PORTIONS OF SAID EXTENSION LEGS, SAID FIRST AND SECOND FLEXIBLE MEMBERS PASSING THROUGH SAID CLAMPING MEANS, AND SAID CAM MEMBER IN SAID CLAMPING MEANS BEING ADAPTED TO ENGAGE SAID FLEXIBLE MEMBERS AND PREVENT MOVEMENT OF SAID FLEXIBLE MEMBERS RELATIVE TO ONE ANOTHER AND TO SAID CLAMPING MEANS UNLESS SAID CLAMPING MEANS IS MANUALLY RELEASED.
References Cited (Backward Citations)
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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) | 1968-03-15 | 1968-09-14 | 1969-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-15 | 1972-09-14 | 1973-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-15 | 1976-09-14 | 1977-03-16 | $7700.00 | Window Closed / Lapsed |