Fire escape – ladder – or scaffold – Ladder – Supporting surface compensating means
Reexamination Certificate
2000-12-29
2002-06-11
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Ladder
Supporting surface compensating means
C182S205000
Reexamination Certificate
active
06401866
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the field of leveling attachments, and more particularly to a machine for leveling a ladder on a uneven surface.
Extension Ladders are useful tools on flat surfaces, but can be quite dangerous on uneven surfaces. This device will make it easier to level a ladder on such surfaces. Ladder leveling attachments in the past were time consuming to set up with pins, locks, bolts, and extra brackets. Plus a lot of extra weight was added to the ladder to drag around. Workmen would attempt to avoid all this extra work and use blocking instead. This would again increase the chance of injury. This machine or device is compact, no loose parts, easy to lock and unlock with just one lever on each side. This device would be lightweight and a permanent part of the ladder making it unnecessary for other attachments or blocks.
Beck
Ladder Leveling Device
U.S. Pat. No.
5,845,744
The Beck device has two housings that bolt to and extend out side each ladder leg. Both housings have a telescoping member with a lever inside attached to the ground end. This lever has a locking pin attached that extends through the telescopic member and engages one of the apertures in the housing, locking the telescoping member to the housing. Moving the lever to the unlock position, disengages the locking pin from the aperture, allowing the telescoping member to move to another position.
Macyszyn
Ladder Level Adjusting Attachment
U.S. Pat. No.
5,542,497
The Macyszyn device works in a similar fashion, but uses a cam self-locking mechanism to apply pressure against the telescoping inner channel member causing it to lock in a set position. A set of safety pins is provided for each inner channel member and is engaged in case of a cam self-locking mechanism failure. This device also mounts on the outside of each leg of the ladder.
Cordell
Leveler attachment for ladders
U.S. Pat. No.
4,802,471
The Cordell device bolts to the out side of each ladder leg with an outer rail. An inner rail telescopes within the outer rail, and is held in place by a gripping mechanism feeding threw an aperture with a sharp edge against the inner rail smooth surface. This gripping mechanism locks the inner rail to the outer rail. Moving the gripping mechanism to the unlock position allowing the inner rail to telescope another position.
There is extensive patent literature relating to ladder leveling devices. Most all of these devices attach to the outside of each ladder leg threw bolts, pins, or some sort of bracket. This tends to make these devices heavy, complicated, and awkward to use. This also increases the width of the ladder limiting the use in fight areas. All the weight on the ladder takes a zigzag path threw the leg, to the mounting bolt, then over to the leveling device, this makes for a weak support. Some of these devices attempt to lock the telescoping member in place by using a locking or gripping mechanism against a smooth surface. These tend to fail after the sharp edge on the locking device has worn. It is not believed that any of these devices have met with considerable commercial success.
SUMMARY OF THE INVENTION
The primary object of the invention is to make a much more compact, lighter, and user-friendlier Ladder Leveling device than any other on the market.
Another object of the invention is a device that supports the weight of the ladder in a straight line, directly under the load and does not increase the width of the ladder that it's installed on.
Another object of the invention is to provide a device that locks with no slip gear type teeth.
A further object of the invention is to provide a device that locks in place with more than one tooth for a strong grip.
Still yet another object of the invention is a device that has fewer parts than most Ladder Level attachments.
Another object of the invention is a device that adds very little weight to the Ladder it's attached to.
Another object of the invention is a locking Mechanism that locks tighter as the weight on the ladder increases.
A further object of the invention is a Release & Lock Lever that cannot be released with weight on the ladder for safety.
Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.
A machine for leveling a ladder on a uneven surface, comprising: A support housing attached to one or both ladder legs, having an interior cavity for a telescoping leg, two outer cavities that allow said ladder to mesh with said support housing, two inner drilled lugs that support a release and lock lever, two outer drilled lugs that overlap said ladder legs, A release and lock lever attached to said support housing, that automatically locks into a telescoping leg by spring action when released, A release and lock lever, rotating on a rotation shaft ,with a positive gear tooth lock that engage into said telescoping leg, A telescoping leg with a large number of machined or molded gear teeth that telescopes out of the interior cavity of said support housing, A telescoping leg that telescopes freely into said support housing when the release and lock lever is released, A release and lock lever that rotates on a shaft and wedges into the telescoping leg according to the weight applied to the ladder, A shoe with a rubber pad with traction material for better gripping attached to said telescoping leg, A shoe that can rotate 180 degrees on said telescoping leg, A spring fixed between said release and lock lever and said support housing to hold the mechanism in the lock position until actuated, A rotation shaft fix between two support housing lugs held in place by lock rings, and.
The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.
REFERENCES:
patent: 970425 (1910-09-01), Curran
patent: 971997 (1910-10-01), Henning
patent: 1419748 (1922-06-01), Miller
patent: 1887495 (1932-11-01), Carter, Jr.
patent: 2152895 (1939-04-01), Longtin
patent: 3016103 (1962-01-01), Studer
patent: 3406785 (1968-10-01), Pilcher
patent: 3527321 (1970-09-01), Brown
patent: 3882966 (1975-05-01), Fasano
patent: 4802471 (1989-02-01), Cordell
patent: 5476153 (1995-12-01), Dickerson et al.
patent: 5497850 (1996-03-01), Patterson
patent: 5542497 (1996-08-01), Macyszyn
patent: 5551529 (1996-09-01), Molitor
patent: 5609222 (1997-03-01), Horbacewicz
patent: 5678656 (1997-10-01), Lanzafame
patent: 5845744 (1998-12-01), Beck
Ladder Man Inc., The Ladder Book Catolog # 002B, p. 62, Part # 09015 and 07019 3025 Silver Drive, Columbus, OH 43224-3962 (www.ladder.com).
Sears Industrial Sales, Catalog. 2000-2001 year, p. 361 p
F9-WN802 Phone 1-800-776-8666, No month available.
Roy Daniel J.
Stodola Daniel P.
Thompson Hugh B.
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