Fire escape – ladder – or scaffold – Ladder and platform
Reexamination Certificate
2002-03-18
2004-11-02
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Ladder and platform
C182S151000, C182S113000, C052S182000
Reexamination Certificate
active
06810995
ABSTRACT:
TECHNICAL FIELD
This invention is directed to the field of portable stairs. More particularly, the invention is directed to improved stairs for use with mobile construction trailers and modular or pre-fab building structures, such as are commonly utilized on construction projects.
BACKGROUND
Various platforms have long been utilized for placing adjacent exit and entry ports, normally conventional doors, found in construction trailers and other similar portable structures. A wide variety of such structures have been known and utilized as appropriate for various applications. And, although most such stairs and accompanying platforms have historically been constructed with fixed, non-adjustable platform heights, a few alternate structures have been developed which, in some limited fashion or another, enable the user to accommodate or provide some adjustment in the platform height.
However, a common problem encountered in locating such structures which are known to me is that, when operating on uneven ground, such structures are often not uniformly adjusted (often are not even variably adjustable) to provide a level platform. Thus, those structures inevitably leave a gap of a few inches between the required or desirable platform height, and the actual platform height. Additionally, a certain amount of tilt often occurs if the stair and platform combination is not carefully set up or assembled, as the case may be. Also, it is often rather difficult to achieve a quick adjustment of the available adjustable designs, so, workmen often found to be simply too lazy or too pressed for time to properly make available adjustments. Often, the result is a job-site trailer with an entrance/exit stairs/platform which does not comply with applicable regulatory requirements, such as the Occupational Safety and Health Act (OSHA), or equivalent state acts, when the projects are in the United States.
Thus, there remains a continuing unmet need for a combination stairs/platform for portable structures which are adjustable in height, and which, even though the platform height is adjustable, can utilize a single stair design, and wherein both the stairs and the platform are fully compliant with applicable regulatory standards.
SOME OF THE OBJECTS, ADVANTAGES, AND NOVEL FEATURES
Accordingly, one objective of my invention is to provide a design for portable stairs which have an adjustable platform height.
Another objective of my invention is to provide a design for portable stairs in which the platform height is adjustable while the same set of stairs is utilized.
Another important objective is to provide a platform structure which is rapidly adjustable in height, yet retains the high strength necessary to support the design load with adequate safety factor.
A related and important objective is to provide a structure in which the platform legs are quickly adjustable, yet of high strength.
Another important objective is to provide a structure and design in a portable stair unit in which the stairs may be conventionally installed, yet can be installed in different heights attached to the same platform, rather than having the requirement for a new set of stairs when the platform height is adjusted.
Finally, another important objective is to provide a high strength portable stair structure which can be conveniently and easily built with conventional manufacturing processes, so that manufacturing costs are minimized.
BRIEF SUMMARY
I have now invented a portable platform and stairs for portable office buildings, where the platform is of adjustable height. This is important since it enables the platform to be reused at different sites, although uneven ground, or building setups of differing heights, is encountered.
My portable stair system has four major components. These components are a platform, a stair assembly, a stair handrail, and a platform handrail.
Importantly, my novel platform has individually adjustable legs, preferably at least four in number. I prefer to use a slidably adjustable mechanism that is securable with friction fit fasteners at any desired length, preferably from more than zero up to at least as much as fourteen inches in height. In this manner, the platform can be adjusted to fit any of the various portable office building types currently available.
Moreover, my platform stair system needs no extra bolts for assembly, and resultantly, it is one of the easiest to assemble stair systems available.
REFERENCES:
patent: 2531778 (1950-11-01), Merner
patent: 3462170 (1969-08-01), Smith et al.
patent: 3693754 (1972-09-01), Butler
patent: 3698511 (1972-10-01), Dohan
patent: 3750351 (1973-08-01), Greenburg
patent: 3796456 (1974-03-01), Bergeson et al.
patent: 3808757 (1974-05-01), Greenwood
patent: 3912298 (1975-10-01), Humphrey
patent: 4042064 (1977-08-01), Lobb
patent: 4347638 (1982-09-01), Weaver
patent: 4418792 (1983-12-01), Cerone
patent: 4747243 (1988-05-01), Anstead
patent: 4759162 (1988-07-01), Wyse
patent: 4909700 (1990-03-01), Fontecchio et al.
patent: 5653459 (1997-08-01), Murphy
patent: 6085867 (2000-07-01), Daniel, III et al.
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