Fire escape – ladder – or scaffold – Ladder with land vehicle
Reexamination Certificate
2000-06-28
2001-11-13
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Ladder with land vehicle
C182S039000
Reexamination Certificate
active
06315078
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a tightening knob which serves as a securing device for a multi-position ladder and the support therefor, and, more particularly, a device that secures the ladder in place while in use or storage.
BACKGROUND OF THE INVENTION
Prior art ladders used in industry and construction are often specifically designed to gain quick access to materials on the roof of a vehicle or on a shelf in a warehouse. In the case of a vehicle, for example, a construction van or truck, the ladder is typically vertically mounted relatively parallel to the side or rear of the vehicle in a single fixedly attached position. In this regard, a worker must maneuver the vehicle prior to loading or unloading materials to orientate the ladder to an accessible position relative to the desired material's site. This, oftentimes, is inconvenient, for example, in tight work zones or storage places.
In the case of a warehouse, typically the ladder must be removed from a storage site, carried to the desired material's location, raised to the desired height for loading or unloading of materials, lowered and then returned to the storage site. This can be burdensome and inconvenient, especially in crowded work zones or if frequent loading and unloading is required.
What is needed is a ladder that may be conveniently moved to an out-of-the-way yet accessible position, conveniently positioned for access to the roof of a vehicle or a shelf of a warehouse, and also readily and conveniently returned to its storage position.
SUMMARY OF THE INVENTION
The present invention provides a tightening knob with threaded posts therein to serve as a security device against lateral shifting of the multi-position ladder while in use and to serve as an additional security measure against involuntary or accidental separation of the ladder from its support member while in storage.
According to one aspect of the invention, the tightening knob includes a knob attached to a threaded post which extends in a generally perpendicular manner against the support member, a second, wider threaded post through which the first threaded post may be threaded, and a lock nut securing the wider threaded post, and having the entire device coupled with the ladder pivot arm. The knob may be twisted manually in either a clockwise or counter-clockwise rotation in order to engage the inner threaded post with the outer threaded post, thus securing the inner threaded post against the support member. This engagement between the inner threaded post and the support member in turn creates a frictional engagement between the threaded post and the support member preventing the ladder from shifting in a lateral direction.
Alternatively, the tightening knob can then be manually rotated in an opposite direction in order to lessen the frictional engagement between the inner threaded post and the support member, thus allowing for lateral movement of the multi-position ladder as needed.
Although the invention is shown and described with respect to one or more preferred embodiments, it is to be understood that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the claims.
REFERENCES:
patent: 6073725 (2000-06-01), Kumher et al.
patent: 6105720 (2000-08-01), Kumher et al.
Kumher Boyd S.
Kumher Don A.
Eschweiler & Associates LLC
Kumher Don A.
Stodola Daniel P.
Thompson Hugh B.
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