Fire escape – ladder – or scaffold – Unitary foldable – rigid scaffold or ladder – Collapsible ladder
Reexamination Certificate
2002-01-17
2002-10-01
Lev, Bruce A. (Department: 3634)
Fire escape, ladder, or scaffold
Unitary foldable, rigid scaffold or ladder
Collapsible ladder
C182S096000, C182S160000
Reexamination Certificate
active
06457559
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates in general to a foldable ladder, and in particular to a foldable ladder with sliding latches to maintain the ladder in an open position.
DESCRIPTION OF THE PRIOR ART
Ladders that fold or collapse are known in the prior art. By folding the ladder the user is able to more easily transport and store the collapsible structure than when in an opened position. At the same time this type of ladder must be safe to use when in an opened position to insure users will not be injured when ascending or descending the rungs.
Folding ladder and associated components are known in the art. For example, U.S. Pat. No. 1,314,201 to Moore discloses a folding ladder in which the vertical rungs fold on themselves.
U.S. Pat. No. 1,606,445 to Pirsch discloses a folding ladder that has cross rungs which pivot to allow the ladder to fold at one or more cross braces.
U.S. Pat. No. 4,842,099 to Collet et al discloses a folding ladder that has cross rungs which pivot to allow the ladder to fold and a pair of pivoting cross braces.
U.S. Pat. No. 5,170,862 to Chang discloses a locking device for a step ladder.
U.S. Pat. No. 5,685,394 to Simson discloses a folding ladder with a pair of cross braces to hold the ladder in an open position.
In the present invention at least two cross rungs having sliding stops which prevent the otherwise foldable rungs from folding when in an opened position. As an added option, a removable pair of wheels with a connecting axle can be attached to the ladder, when in an opened position, to permit the ladder to carry cargo, all as will be detailed in the specification that follows hereafter.
SUMMARY OF THE INVENTION
This invention relates to a foldable ladder having locking brackets on the rungs to maintain the ladder in an opened position.
It is the primary object of the present invention to provide for an improved foldable ladder that can safely support a user while in the opened position.
Another object is to provide for such a ladder in which slidable stops on at least two rungs prevent the ladder from folding when in an opened position.
An additional further object to provide such a ladder having a pair of detachable wheels and supports for carrying cargo when the ladder is in an opened position.
These and other objects and advantages of the present invention will become apparent to readers from a consideration of the ensuing description and the accompanying drawings.
REFERENCES:
patent: 1314201 (1919-08-01), Moore
patent: 3370865 (1968-02-01), Baldwin
patent: 4612848 (1986-09-01), Pollack
patent: 4934485 (1990-06-01), Purkapile
patent: 5170862 (1992-12-01), Chang
patent: 5868222 (1999-02-01), Charbonneau
patent: 5944141 (1999-08-01), Kochan et al.
patent: 5967257 (1999-10-01), Begin et al.
patent: 6119811 (2000-09-01), Tsung-Ping
patent: 6145621 (2000-11-01), Nye
patent: 6318498 (2001-11-01), Warner
Schlueter Mark R.
Schlueter Tami Lee
Lev Bruce A.
McGlynn Joseph H.
Patent & Trademark Services
Zack Thomas
LandOfFree
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