Patent US2190596A successfully refreshed from Google Patents.
US3791487A
Expired / Lapsed
US
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Rail extension device for ladders
Assignee: Individual
•
Filing: 1973-04-20
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Granted: 1974-02-12
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Expires: 1993-04-20
Abstract
Abstract An extension device attachable to the side rails of ladders that is adjustable to maintain the ladders in vertical positions upon uneven supporting surfaces, said device being readily manipulated to the desired rail extended condition and adapted to retain that condition when the ladder is set up or when the ladder is moved from one place to another.
Inventors
- 👤 A Baumann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:08
CPC Classifications
E; E06; E06C; E06C7/00; E06C7/42; E06C7/44
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
143 words
An extension device for attachment to a ladder rail consisting of a U-shaped rail mounted bracket, an upstanding tubular extension member mounted for axial, sliding movement in the bracket, said member having a square configuration in lateral section, a screw thread segment formed in each of the longitudinally extending corners of the extension member, said thread being interrupted by the flat exterior sides of the member between said adjacent corners, a nut bearing against the bottom edge of the bracket and cooperable with the thread segments in the extension member, a foot on the lower end portion of the extension member, and a spring means interposed between the bracket and the extension member in frictional engagement with a flat exterior side of the member between the adjacent threaded corners thereof, and biased to preclude undesirable axial movements of the member in the bracket.
Claim 2
Dependent Claim
143 words
An extension device for attachment to a ladder rail consisting of a U-shaped rail mounted bracket, an upstanding tubular extension member mounted for axial, sliding movement in the bracket, said member having a square configuration in lateral section, a screw thread segment formed in each of the longitudinally extending corners of the extension member, said thread being interrupted by the flat exterior sides of the member between said adjacent corners, a nut bearing against the bottom edge of the bracket and cooperable with the thread segments in the extension member, a foot on the lower end portion of the extension member, and a spring means interposed between the bracket and the extension member in frictional engagement with a flat exterior side of the member between the adjacent threaded corners thereof, and biased to preclude undesirable axial movements of the member in the bracket.
Claim 3
Dependent Claim
28 words
An extension device for attachment to a ladder rail as set forth in claim 1 wherein the spring means is a leaf spring having a preformed, bowed configuration.
Claim 4
Dependent Claim
38 words
An extension device for attachment to a ladder rail as set forth in claim 2 wherein the spring has integral lugs formed at the ends thereof, and the bracket has longitudinally spaced holes therein for receiving said lugs.
Claim 5
Dependent Claim
32 words
An extension Device for attachment to a ladder rail as set forth in claim 1 wherein a standard fine screw thread is chased in the longitudinally extending corners of the extension member.
Claim 6
Dependent Claim
58 words
An extension device for attachment to a ladder rail as set forth in claim 1 wherein the lower portion of the tubular extension member has a pair of opposed longitudinally extending slots formed therein, and the foot member has a pair of spaced ears, and a pin is fixed in the ears and freely extends through the slots.
References Cited (Backward Citations)
US758743A
Cited
US2318017A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |