Fire escape – ladder – or scaffold – Ladder – Supporting surface compensating means
Reexamination Certificate
2001-04-10
2003-04-15
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Ladder
Supporting surface compensating means
Reexamination Certificate
active
06547036
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to ladder leveling devices and, more particularly, to an apparatus for supporting the leg of a ladder and for stabilizing the supporting member on a stairway.
Workers who use ladders are frequently faced with placing a ladder on uneven ground or even on stairs. When the legs of a ladder are uneven, workers sometimes resort to the use of bricks, boards, cement blocks, or whatever else is handy to augment the length of one of the legs. Obviously, this type of adjustment leads to an unstable and unsafe work environment which could, and sometimes does, result in serious injury.
Various devices have been proposed for leveling the legs of a ladder in the context of an uneven ground or support surface. Although assumably effective for their intended purposes, existing devices often require a ladder to be permanently modified to accommodate the device and often do not provide assurance that the ladder is level following adjustment.
Therefore, it is desirable to have an apparatus which adjustably supports a leg of a ladder a selectable distance above a support surface. Further, it is desirable to have an apparatus which includes a platform for stabilizing the ladder leg support member upon the stairs of a stairway. Finally, it is desirable to have an apparatus which includes a sight level for verifying that the stabilizing platform itself is level.
SUMMARY OF THE INVENTION
A ladder leg support apparatus according to this invention includes a support member having a truncated tetrahedral configuration with a base plate, upstanding inner side and back walls, and inclined outer side and back walls. The inner side and back walls define an interior space and an open front and open top. A plurality of opposed support flanges along the inner side walls allow a support plate to be selectably positioned a selected distance above the base plate. In turn, the support plate is adapted to support a ladder leg thereon. The support member further includes at least one auxiliary side panel pivotally coupled to an outer side wall. The auxiliary side panel includes a plurality of threaded apertures in which a support leg may be positioned when the auxiliary side panel is pivoted to a configuration coextensive with the base plate. The support leg is threadably adjustable such that the support leg may contact the surface of a stair downwardly adjacent a stair on which the support member is placed. This configuration provides stability when a ladder leg is supported atop the support plate.
The apparatus further includes a platform having a support surface which may be positioned upon a selected stair of a staircase and is adapted for supporting the support member thereon. The platform includes a pair of leg assemblies having support legs that are threadably adjustable to contact the surface of a downwardly adjacent stair and thus to stabilize the platform support surface and support member on the selected stair. At least one sight level is mounted to a frame of the platform so that a user may verify that the platform is level following an adjustment of the support legs.
Therefore, a general object of this invention is to provide a ladder leg support apparatus which supports and stabilizes a ladder leg positioned on an uneven support surface.
Another object of this invention is to provide an apparatus, as aforesaid, which distributes the weight load of a ladder and a worker thereon over a broad base assembly.
Still another object of this invention is to provide an apparatus, as aforesaid, that is easily adjustable to support a ladder leg at selectable heights above a support surface.
Yet another object of this invention is to provide an apparatus, as aforesaid, which minimizes the risk of ladder leg slippage.
A further object of this invention is to provide an apparatus, as aforesaid, that is universally usable with two-rail ladders.
A still further object of this invention is to provide an apparatus, as aforesaid, that is constructed of durable materials that are economical to manufacture.
Another object of this invention is to provide an apparatus, as aforesaid, having a sight level for verifying that the platform is level.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.
REFERENCES:
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patent: 4304318 (1981-12-01), Webb
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patent: 5615752 (1997-04-01), Wassil
patent: 5791438 (1998-08-01), Kempton
patent: 5975471 (1999-11-01), Dishman
patent: 6044929 (2000-04-01), Wishner
patent: 6053284 (2000-04-01), Fountain
patent: 2663075 (1991-12-01), None
patent: 2057040 (1981-03-01), None
patent: 2244506 (1991-12-01), None
Carter Boyce N.
Chin-Shue Alvin
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