US3390739A

US3390739A - Ladder leveling device

Info

Publication number: US3390739A
Application number: US639939A
Authority: US
Inventors: Frederick A Hastings
Original assignee: Frederick A. Hastings
Current assignee: FREDERICK A HASTINGS
Priority date: 1967-05-15
Filing date: 1967-05-15
Publication date: 1968-07-02
Anticipated expiration: 1985-07-02

Description

y 2, 1968v F. A. H ASTINS 3,390,739

LADDER LEVELING DEVICE Filed May 15, 1967 BY g I fir Mir-9 United States Patent 3,390,739 LADDER LEVELING DEVICE Frederick A. Hastings, RR. 4, Rome, N.Y. 13440 Filed May 15, 1967, Ser. No. 639,939 2 Claims. (Cl. 182108) ABSTRACT OF THE DISCLOSURE A ladder leveling device consisting of a crescent-shaped wedge for insertion between a ladder base and the ground or base plane, the wedge surfaces (upper and lower) being developed on different radii of curvature for optimum locking action.

This invention in general relates to ladders and more particularly to a novel device for facilitating the engagement and support of the ladder with uneven surfaces.

In the past in order to compensate for uneven ground when leveling or supporting a ladder, one leg of the ladder was placed on a block of wood. This proved to be only partially effective since in many instances the block was unstable and therefore dangerous.

In order to overcome the above shortcomings, complicated, cumbersome structures such as that described in Patent No. 2,552,941 were devised.

One of the primary objects of my invention is to provide a simple ladder leveling device which is both a fast and safe means of supporting a ladder on unlevel ground surfaces.

Another object of my invention is to provide a completely adjustable ladder leveling device which will be light, durable and efficient in use, one that will be simple and easy to manufacture and one which can be placed upon the market at a low cost.

A further object of my invention is to provide a ladder leveling device which can be used to level and/or support any leg of a ladder.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevation of the device supporting an ordinary ladder leg; and

FIGURE 2 is a plan view taken along line 2-2 of FIGURE 1.

The leg of a ladder can be of any type now found in the open market.

My device 12 is comprised of hard rubber or similar material shaped like one-half of a quarter moon. It has an inner curved surface 14 which is circular having an equal radius of curvature about point 26. It has an outer curved surface 16 which has continually increasing radii of curvature about point 26 starting at 18 and terminating at 20. Either the inner curved surface or the outer curved surface or both may be ribbed or corrugated partially or in whole to prevent slippage. The device should be positioned such that the force along the leg 10 extends directly through a center line 22 to a resting surface 24. For optimum stability the width of the device W must equal the maximum height H and must be greater than twice the leg width LW.

In use my device 12 is installed by curling it under either leg, whichever is suspended above the ground until the ladder becomes secure, the most secure position being when the force exerted by the leg 10 extends directly through a center line 22 to the resting surface 24.

While a preferred embodiment of the invention has been shown and described, a skilled artisan may make minor changes without departing from the spirit of the invention and the scope of the appended claims.

I claim:

1. In combination, a ladder having at least one leg of predetermined width and a ladder leveling device comprising a crescent-shaped wedge having inner and outer curved surfaces to be inserted between said leg and a base plane, said inner curved surface being circular and having an equal radius of curvature about a fixed point, said outer curved surface having a continually increasing of radii of curvature about said fixed point, the width of said device being equal to the height of said device and being greater than twice the ladder leg width whereby the ladder can be supported in a level position.

2. The combination as defined in claim 1 wherein said device is made of hard rubber.

References Cited UNITED STATES PATENTS 1,915,320 6/1933 Jones 248-1882 3,030,730 4/ 1962 Costar 248-1882 3,338,539 8/ 1967 Foster 248-188.2

FOREIGN PATENTS 128,449 6/ 1919 Great Britain.

REINALDO P. MACHADO, Primary Examiner.