Fire escape – ladder – or scaffold – Means maintaining step lever on horizontally pivoted ladder
Reexamination Certificate
2001-05-30
2003-03-04
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Means maintaining step lever on horizontally pivoted ladder
C052S183000
Reexamination Certificate
active
06527081
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an embankment stairway and particularly to a portable embankment stairway so designed that it can be secured to the ground and its steps fixed in an adjusted position appropriate for the inclination of the part of the embankment on which the stairway is installed.
BACKGROUND OF THE INVENTION
During the construction and repair of throughways, i.e. railways and automotive roads, it is often necessary to build or repair bridges having a lattice work of supporting trestles. These bridges and trestles span valleys, gorges and the like and may rise to considerable heights, depending on the height of the associated embankment. As such, the construction and upkeep of these structures often places workers in precarious and/or treacherous situations as they attempt to scale or remain safely footed upon the various associated embankments. These embankments often have sections of different pitches or inclinations. There exists a great need for a safe temporary stairway for embankments and other inclines, such as are often associated with bridges and trestles, which can be quickly installed with steps adjusted for the slope of the inclination.
An ideal stairway must not only be safe, but also easily portable. For example, as additional supporting trestles are completed during construction, an ideal platform must be moved to facilitate new work, such as for the further expansion of the trestle system. Thus, as construction and/or repair moves to different sites along an embankment, so must the embankment stairway. The embankments involved in railway bridges and trestle construction may be hundreds of feet in length with variations in slope. This creates the need for a considerable number of stairway sections with steps that can be adjusted for the slope on which each section is installed so as to provide level step treads.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a portable embankment stairway that provides level footing over a wide range of stairway angles.
It is another object of the present invention to provide a portable embankment stairway whose steps can be adjusted so that the treads of the steps are coplanar to form a walkway or work platform.
It is another object of the present invention to provide a portable embankment stairway having pivotably adjusted steps permitting a series of such stairways to be advantageously installed on an embankment with an irregular slope.
It is another object of the present invention to provide a portable embankment stairway that is compact for easy storage and transportation.
It is another object of the present invention to provide a portable stairway that is lightweight for easy assembly and movement.
These and other objects are obtainable by providing a portable embankment stairway adapted to be staked to the ground, which includes a frame having a pair of parallel side rails and a plurality of steps pivotally connected to and transversely disposed between the side rails, the steps being adjustable to provide level step treads for a wide range of embankment slopes.
REFERENCES:
patent: 501694 (1893-07-01), Richards
patent: 1167893 (1916-01-01), Fickinger
patent: 2245825 (1941-06-01), Ross
patent: 3299590 (1967-01-01), Carter
patent: 3470664 (1969-10-01), Whitehead
patent: 4421206 (1983-12-01), Kummerlin
patent: 4959935 (1990-10-01), Stob
patent: 5329871 (1994-07-01), Gibbs
patent: 117 582 (1946-11-01), None
Bennett Ronald W.
Tyner Sandy W.
Aluminum Ladder Company
Chin-Shue Alvin
Nexsen Pruet Jacobs & Pollard LLC
Schwab Charles L.
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