Fire escape – ladder – or scaffold – Ladder – Supporting surface compensating means
Reexamination Certificate
1999-12-17
2001-05-22
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Ladder
Supporting surface compensating means
C182S201000
Reexamination Certificate
active
06234273
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to adjustable ladders and more particularly pertains to a new adjustable ladder for leveling a ladder on an uneven surface.
2. Description of the Prior Art
The use of adjustable ladders is known in the prior art. More specifically, adjustable ladders heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. Nos. 5,273,133; 4,128,139; 2,451,113; 2,894,670; 3,878,918; and U.S. Pat. Des. No. 359,365.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new adjustable ladder. The inventive device includes a ladder and leveling system. The ladder has a first leg, a second leg, and a plurality of rungs extending between the legs. A bottom end of the first leg is hollow and defines a cavity therein. An extension leg extends the length of the first leg. The extension leg comprises a housing which is slidably received in the cavity of the first leg and is adapted to selectively move inward and outward of the cavity for increasing and decreasing an effective length of the first leg. A plurality of bores are located in the first wall of the housing. Each of the bores in the first wall has a diametrically opposed and axially aligned bore in a second wall of the housing. A pin for selectively locking the housing in position with respect to the first leg is insertable through a pair of diametrically opposed bores in the first leg. The opposing bores in the housing and the opposing bores in the first leg are aligned for inserting the pin therethrough for locking the housing.
In these respects, the adjustable ladder according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of leveling a ladder on an uneven surface.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of adjustable ladders now present in the prior art, the present invention provides a new adjustable ladder construction wherein the same can be utilized for leveling a ladder on an uneven surface.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new adjustable ladder apparatus and method which has many of the advantages of the adjustable ladders mentioned heretofore and many novel features that result in a new adjustable ladder which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art adjustable ladders, either alone or in any combination thereof.
To attain this, the present invention generally comprises a ladder and leveling system. The ladder has a first leg, a second leg, and a plurality of rungs extending between the legs. A bottom end of the first leg is hollow and defines a cavity therein. An extension leg extends the length of the first leg. The extension leg comprises a housing which is slidably received in the cavity of the first leg and is adapted to selectively move inward and outward of the cavity for increasing and decreasing an effective length of the first leg. A plurality of bores are located in the first wall of the housing. Each of the bores in the first wall has a diametrically opposed and axially aligned bore in a second wall of the housing. A pin for selectively locking the housing in position with respect to the first leg is insertable through a pair of diametrically opposed bores in the first leg. The opposing bores in the housing and the opposing bores in the first leg are aligned for inserting the pin therethrough for locking the housing.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
It is therefore an object of the present invention to provide a new adjustable ladder apparatus and method which has many of the advantages of the adjustable ladders mentioned heretofore and many novel features that result in a new adjustable ladder which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art adjustable ladders, either alone or in any combination thereof.
It is another object of the present invention to provide a new adjustable ladder which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new adjustable ladder which is of a durable and reliable construction.
An even further object of the present invention is to provide a new adjustable ladder which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such adjustable ladder economically available to the buying public.
Still yet another object of the present invention is to provide a new adjustable ladder which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new adjustable ladder for leveling a ladder on an uneven surface.
Yet another object of the present invention is to provide a new adjustable ladder which includes a ladder and leveling system. The ladder has a first leg, a second leg, and a plurality of rungs extending between the legs. A bottom end of the first leg is hollow and defines a cavity therein. An extension leg extends the length of the first leg. The extension leg comprises a housing which is slidably received in the cavity of the first leg and is adapted to selectively move inward and outward of the cavity for increasing and decreasing an effective length of the first leg. A plurality of bores are located in the first wall of the housing. Each of the bores in the first wall has a diametrically opposed and axially aligned bore in a second wall of the housing. A pin for selectively locking the housing in position with respect to the first leg is insertable through a pair of diametrically opposed bores in the first leg. The opposing bores in the housing and the opposing bores in the first leg are aligned for inserting the pin therethrough for locking the housing.
Still yet another object of the present invention is to provide a new adjustable ladder that contains a level for determining exactly when the rungs of the ladder are level.
Even still another object of the present inventio
Stodola Daniel P.
Thompson Hugh B.
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