US3794141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for adapting the lengths of a pair of legs, such as those of a ladder, to unevenness of a supporting surface
Assignee: Individual
•
Filing: 1972-10-24
•
Granted: 1974-02-26
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Expires: 1992-10-24
Abstract
Abstract A device is provided which can be mounted at the lower end of a ladder for adapting the legs of the ladder to the unevenness of the ground. The device comprises two extension legs which are mounted for telescoping movement into and out of the respective ends of a U-shaped tubular member which is fastened to the ladder. The extension legs are interconnected through the tubular member by means of a longitudinal flexible member having a series of longitudinally spaced recesses on its outer surface. The Ushaped tubular member has an expanded portion midway between its legs so that the longitudinal flexible member will bulge into the expanded portion when pressure is applied to both extension legs. A number of mutually spaced projections are provided inside the expanded portion for fitting into the recesses on the flexible member when it bulges into the expanded portion to lock the flexible member in position relative to the tubular member.
Inventors
- 👤 W Sturm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:38
CPC Classifications
E; E06; E06C; E06C7/00; E06C7/42; E06C7/44
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
252 words
An apparatus for aDjusting the lengths of a pair of legs, particularly of a ladder, to match irregularities in the ground, including two extension legs mounted at a distance from each other, an upper part which can be attached to the pair of legs, the two extension legs being attached to be displaceable up and down on the upper part, the upper part having a tubular structure which begins in the extension of one extension leg, extends across to the other extension leg, and ends in the extension of another extension leg, a chain-like connecting element mounted in the tubular structure to be displaceable in the direction of its longitudinal extension, the connecting member being connected at one of its two ends to one of the two extension legs, having on the outer side recesses provided in series in the direction of its longitudinal extension and consisting of a continuous core and links threaded thereon, projections which are mounted in series at a distance from the chain-like connecting member in the direction of the longitudinal extension of the connecting member fitting into the recesses of the chain-like connecting member, the improvement being that said tubular structure, in its transverse section, defines an expansion directed towards only one side and in which the projections are mounted and opposite the expansion forms a curvature aligned with the expansion in which the chain-like connecting member in the tubular structure, apart from the expansion, is not movable transversely to the center axis of the tubular structure.
Claim 2
Independent Claim
252 words
An apparatus for aDjusting the lengths of a pair of legs, particularly of a ladder, to match irregularities in the ground, including two extension legs mounted at a distance from each other, an upper part which can be attached to the pair of legs, the two extension legs being attached to be displaceable up and down on the upper part, the upper part having a tubular structure which begins in the extension of one extension leg, extends across to the other extension leg, and ends in the extension of another extension leg, a chain-like connecting element mounted in the tubular structure to be displaceable in the direction of its longitudinal extension, the connecting member being connected at one of its two ends to one of the two extension legs, having on the outer side recesses provided in series in the direction of its longitudinal extension and consisting of a continuous core and links threaded thereon, projections which are mounted in series at a distance from the chain-like connecting member in the direction of the longitudinal extension of the connecting member fitting into the recesses of the chain-like connecting member, the improvement being that said tubular structure, in its transverse section, defines an expansion directed towards only one side and in which the projections are mounted and opposite the expansion forms a curvature aligned with the expansion in which the chain-like connecting member in the tubular structure, apart from the expansion, is not movable transversely to the center axis of the tubular structure.
Claim 3
Dependent Claim
23 words
The apparatus as claimed in claim 1 in which the tubular structure is flexible on either side of the zone having the expansion.
Claim 4
Dependent Claim
72 words
The apparatus as claimed in claim 1, in which the chain-like connecting element has a core of steel wires attached at each end to the extension legs, balls threaded on said steel wires, an insert mounted on the core between each two balls, and a spherical recess facing each of the two balls with the ball housed therein and whose outer diameter across the core is smaller than that of the ball.
Claim 5
Dependent Claim
53 words
The apparatus as claimed in claim 1, in which each extension leg is mounted in a correspondingly shaped bore of a tubular guide and tapers in diameter upwardly above a shoulder and the tapered section of the extension leg as well as the chain-like connecting member being adapted to each other in diameter.
Claim 6
Dependent Claim
27 words
The apparatus as claimed in claim 3, in which the spacing between two adjacent projections corresponds to half the spacing between the centers of two adjacent balls.
References Cited (Backward Citations)
US3102606A
Cited
US3090466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |