Fire escape – ladder – or scaffold – Ladder and platform – Platform with ladder as support
Reexamination Certificate
2003-02-20
2004-09-07
Lev, Bruce A. (Department: 3634)
Fire escape, ladder, or scaffold
Ladder and platform
Platform with ladder as support
C182S121000, C182S122000, C248S236000
Reexamination Certificate
active
06786300
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to ladder steps, and more particularly to a unitary step attachment adapted to be releasably mounted on the step of a conventional ladder for increasing the width of the existing step.
2. Brief Description of the Prior Art
Steps on a conventional ladder are narrow and do not provide a very satisfactory foot support, especially when prolonged standing on a single step is required. Various step attachments are known in the prior art which are adapted to be mounted on a conventional ladder for increasing the width of the existing step. Most of these prior art devices are complex and require fasteners to secure them to the side rails, rung, or step of the ladder, and are not easily installed and removed.
Some prior art patents have a fault wherein the platform upon which the user may place his feet, extends either in front of the rung, or immediately over it, presenting a potential hazard by which the user may trip. For example, Miller, U.S. Pat. No. 1,820,315 discloses a step attachment for ladders with a platform that hangs off of the rung, and in front thereof.
Hartman et al, U.S. Pat. No. 2,486,783 discloses a platform attachment for rung type ladders that is disposed upon the front side of the ladder and over the rung. Also, the platform itself raises the tread for the user above the rung. This could be dangerous in as much as the user might inadvertently miss that spot.
Roberts, U.S. Pat. No. 3,115,214 discloses a portable step attachment for extension ladders which hangs out in front of the ladder and is secured to a rung. The platform has a central portion that is pivotal up and out of the way to permit the user some access around the platform. Roberts thereby acknowledges the difficulty with getting over a platform on a ladder, however he fails to deal with the inherent problem of having the platform in front of the ladder rung.
Skaggs, U.S. Pat. No. 4,911,265 discloses a work-step platform attachment for an extension ladder that has a hooking element which engages a rung of the ladder and a locking element to lock the platform in a first position in which it is aligned with the rung, and a second position in which it is substantially aligned in the plane of the parallel side frames of the ladder.
Canals, U.S. Pat. No. 4,586,586 discloses a work step for an extension ladder having a platform that engages a lower rung of the ladder and brackets for securing it to an upper rung of the ladder. The platform is pivotal about a rung adjacent to the platform, and has a complicated locking mechanism whereby the platform may be held parallel to the side frame of the ladder. The platform extends onto the rung of the ladder and extends slightly forward of it.
Zumwalt et al, U.S. Pat. No. 5,056,620 discloses a stepladder platform that is particularly adapted for use with channel-type step ladders which provides an enlarged foot-resting platform and has engagement means which prevent lateral (inward or outward) movement and tilting movement in one or both possible tilt directions. In the deployed position, the platform extends inward and outward on both sides of the step and forward of the ladder.
Spalt et al, U.S. Pat. No. 5,337,857 discloses a platform for an aluminum extension ladder that is adjustable upwardly and downwardly, and is pivotally connected between a pair of side frame members slidably mounted on the side rails of the ladder.
The present invention is distinguished over the prior art in general, and these patents in particular by a unitary step unit having a generally rectangular main body portion with opposed transverse ends and laterally opposed sides. One end is bent downward and angularly outward with respect to the main body portion and terminates in a short upturned lip that extends angularly upward and inward. The step unit is removably installed on the existing step of a conventional ladder having channel-shaped steps by engaging the upturned lip against the bottom edge of the down-turned longitudinal side of the step and then pivoting the unit downwardly such that the upturned lip of the unit is captured on the bottom edge of the down-turned longitudinal side of the step and its main body portion is supported on top of the step and extends a distance rearwardly beyond the width of the step in cantilever fashion to provide a relatively wide flat foot-supporting surface.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a portable step unit that is easily and quickly installed on and removed from the step of a conventional ladder to increase the width of the existing step.
It is another object of this invention to provide a portable step unit that is easily and quickly installed on and removed from the step of a conventional ladder to provide a relatively wide flat foot-supporting surface.
Another object of this invention is to provide a portable step unit that is easily and quickly installed on and removed from the step of a conventional ladder to provide a rigid safe foot-supporting surface.
A further object of this invention is to provide a portable step unit that is easily and quickly installed on and removed from the step of a conventional ladder that is simple in construction, inexpensive to manufacture, and rugged and reliable in operation.
Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related.
The above noted objects and other objects of the invention are accomplished by a unitary step unit having a generally rectangular main body portion with opposed transverse ends and laterally opposed sides. One end is bent downward and angularly outward with respect to the main body portion and terminates in a short upturned lip that extends angularly upward and inward. The step unit is removably installed on the existing step of a conventional ladder having channel-shaped steps by engaging the upturned lip against the bottom edge of the down-turned longitudinal side of the step and then pivoting the unit downwardly such that the upturned lip of the unit is captured on the bottom edge of the down-turned longitudinal side of the step and its main body portion is supported on top of the step and extends a distance rearwardly beyond the width of the step in cantilever fashion to provide a relatively wide flat foot-supporting surface.
REFERENCES:
patent: 335051 (1886-01-01), Ayres
patent: 1820315 (1931-08-01), Miller
patent: 2066108 (1936-12-01), Hedges
patent: 2418597 (1947-04-01), Neff
patent: 2444096 (1948-06-01), Faust
patent: 2486783 (1949-11-01), Hartman et al.
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patent: 3115214 (1963-12-01), Roberts
patent: 3294197 (1966-12-01), Kwiatkowski
patent: 3422923 (1969-01-01), Lund
patent: 4437544 (1984-03-01), Anderson et al.
patent: 4586586 (1986-05-01), Canals
patent: 4911265 (1990-03-01), Skaggs
patent: 5056620 (1991-10-01), Zumwalt et al.
patent: 5158023 (1992-10-01), Allen
patent: 5337857 (1994-08-01), Spalt et al.
patent: 5460241 (1995-10-01), LaBelle
patent: 5975240 (1999-11-01), O'Brien
patent: 6467577 (2002-10-01), Charlebois, Jr.
patent: 6637548 (2003-10-01), Pass
Lev Bruce A.
Roddy Kenneth A.
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