US3527321A - Ladder leveling device - Google Patents

Description

\NVENTOR THOMAS J. BROWN DEAN LAURENCE ATTORNEY Sept; 8, 1970 T. J. BROWN LADDER LEVELING DEVICE Filed March 17, 1969 United States Patent Oflice 3,527,321 Patented Sept. 8, 1970 3,527,321 LADDER LEVELING DEVICE Thomas J. Brown, Rte. 3, Ridge Road, Box 114, Yazoo City, Miss. 39194 Filed Mar. 17, 1969, Ser. No. 807,518 Int. Cl. E06c 7/44 U.S. Cl. 182-205 4 Claims ABSTRACT OF THE DISCLOSURE A device which allows ladders to be quickly leveled and firmly placed on uneven ground. The device has a ratchet mechanism contained in a telescoping sleeve attached to the bottom of the ladder rail. A spring attached to the outer sleeve allows for the automatic extension and positioning of the leg and easy shorting of the leg.

BACKGROUND OF THE INVENTION The present invention relates to a ladder leveling device. More particularly it relates to a device which allows for the leveling of a ladder standing on an uneven base by extending one or more of the ladder rails.

Painters and other workmen who use ladders in their trade often have to erect the ladders on an uneven surface such as hillsides, stairs, ramps, and such. Many methods have been devised for dealing with the problem including wedging rocks or blocks under the short leg, which is dangerous, and various forms of ladder rail extenders.

Many of the extender devices of the prior art such as Bratt 1,718,891 and Kimes 2,350,116 use a knurled knob, wedge or claw to directly engage the ladder rail. These systems suffer from two serious deficiencies; they depend on frictional engagement to maintain the adjustment and the device makes direct and destructive contact with the material of the ladder rail resulting in a chewing up of the rail and a shortened useful life for the ladder.

The prior art has also used a ratchet type device.

Curran in U.S. Pat. 970,425 shows a ratchet device wherein t-wo toothed racks must be manually engaged and disengaged. This device would be difficult to adjust because it necessitates manually engaging and disengaging the teeth of the ratchet while supporting the ladder.

De Stefano in U.S. Pat. 2,517,771 discloses another device which necessitates the manual disengagement of the ratchet before adjustment can be made in either direction.

SUMMARY OF THE INVENTION It is the general object of the invention to avoid and overcome the foregoing and other difficulties and objections to prior art devices by providing a safe, simple, inexpensive and easily operable leveling device.

Another object of the invention is to provide a ladder with a leveling device which will attach to and adjust the length of one or more ladder side rails.

A further object is to provide a device which will protect and not damage the ladder side rails.

Still a further object is to provide a leveling device for a ladder which automatically provides a positive lock when extended.

Another object of the invention is to provide a ladder extending device which can be extended by the force derived from the foot of the operator.

An additional object of the invention is to provide a ladder leveling device constructed with the minimum number of operating components.

The aforesaid objects of the invention and other objects will become apparent on reading the description. These objects are achieved by providing a device attached to the base of a ladder rail which as inner and outer telescoping members. The inner member or sleeve is attached to the lower end of a ladder rail by any means known in the art such as nails, screws, crimp, rivets, etc. Most preferably the inner sleeve would be screwed on to a wooden ladder rail and riveted or welded to a metal ladder rail.

The inner sleeve covers and protects the four faces of the ladder rail. On one face of the inner sleeve is a ratchet rack. This ratchet rack may be integrally formed on the surface of the inner sleeve or permanently attached thereto by welding, bolting or any other such means known to the art. Preferably the ratchet rack is welded to the face of the inner sleeve which faces toward the ground when the ladder is in place. The teeth of the ratchet rack are inclined downwardly and outwardly so the flat surface of a tooth of the rack is toward the base of the ladder.

The inner sleeve is made of metal. Preferably the sleeve is made of a strong resistant metal which will provide strong structural support for th ratchet of the device. Most preferably the sleeve and ratchet rack are made of steel.

The outer member or sleeve is slidably mounted over said inner sleeve. The outer sleeve completely covers the inner sleeve when the device is in the retracted position. The outer sleeve is provided with a foot either integrally formed thereon or attached to the outer sleeve to improve the foundation and support afforded the ladder. The foot can be of a type ordinarily available for attachment to ladder rails and may be permanently or temporarily attached.

On an inner face of the outer sleeve there is provided a tension means so positioned that it will act as a pawl in conjunction with a ratchet on the inner sleeve allowing for the adjustment of the leveling device.

Preferably the pawl is a flat spring which extends upward and outward from the inner face of the outer sleeve at an angle substantially similar to the inclination of the teeth of the ratchet. The tension force in the pawl is directed away from the face of the outer sleeve to which the pawl is attached. The pawl is attached to the outer sleeve by means well known in the art. Most preferably the pawl is welded to the outer sleeve. The pawl is a fiat spring made of any material commonly used to provide a resilient structurally strong spring, preferably the pawl is made of metal and most preferably of steel.

Attached to said pawl is a disengagement means for removing the pawl from contact with a tooth of the ratchet and thereby allowing the retraction of the outer sleeve. An opening is provided in the outer sleeve to allow access to the retraction means. Preferably the retraction means is a projection permanently attached to said pawl, and most preferably the retraction means is a knob attached to a post welded to the fiat spring pawl.

The outer sleeve is made of metal. Preferably the sleeve is made of a strong resistant metal most preferably the outer sleeve is made of steel.

Both the inner and outer sleeve may be made more resistant to weathering and also be made self lubricating by coating and bonding to the surfaces thereof a plastic material such as polyethylene or polyfuronated hydrocarbons such as Teflon by means known in the art.

The flat spring pawl of the device provides sufficient tension against the inner sleeve to frictionally maintain the outer sleeve of the leveling device in engagement with the inner sleeve of the device so the ladder may be moved about without the outer sleeve falling off, yet when the ladder is being positioned a very slight pressure by the operator on the outer sleeve will extend the outer sleeve to the desired length and the flat spring pawl will automatically and positively engage the ratchet therefore pro viding a firm and steady ladder base.

3 BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view of a stepladder, on a level surface, having the leveling device secured at each side rail thereof.

FIG. 2 is a front elevation view of a ladder, on an uneven surface, having the leveling device secured to each rail thereof.

FIG. 3 is a' sectional view of the apparatus.

FIG. 4 is a horizontal sectional view of the device taken along line 4-4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown a ladder having vertically extending side rails 11 interconnected by laterally spaced horizontal rungs 12. A ladder leveling device 13 is positioned on the lower portion of the side rail 11.

In the retracted position as seen in FIG. 1, all that is visible of the leveling device 13 is an outer sleeve 20 with a shaft 24 terminating in a knob 25 protruding therefrom.

'In FIG. 2 the device is shown in an extended position with the inner sleeve 30 emerging from the outer sleeve 20 as it is lowered to compensate for the sloping land.

As shown in FIG. 4 the ladder leveling device 13 has an outer sleeve 20 terminating in a foot 27. A channel 21 is provided in the outer sleeve 20 to slidably receive inner sleeve 30 including the ratchet rack 31. The outer sleeve 20 has a flat spring 22 afiixed to it in a channel 23 provided therefor. The tension in the flat spring 22 forces the spring into engagement with a tooth 32 of the ratchet rack 31 thereby preventing the downward movement of the inner sleeve 30. As can be seen in FIGS. 2 and 4 the inner sleeve 30 is afiixed to the rail 11! of ladder 10.

Again referring to FIGS. 3 and 4 a shaft 24 projecting through opening 26 in outer sleeve 20, and terminating in knob 25 is provided for disengaging flat spring 22 from tooth 32, and retracting spring 22 into groove 23 to allow inner sleeve 30 to telescope along channel 21 into outer sleeve 20.

Although the device is shown on a stepladder it will work equally as well on a pole ladder and the device is not limited by the material from which the ladder is made.

It should be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and modifications and changes may be made in the shape, size and material without departing from the spirit and scope of the invention as claimed.

What I claim is:

1. A ladder leveling device in combination with ladder rails which comprises an inner and outer member, said inner member being attached to the base of said ladder rails and having on one face thereof a ratchet rack, said outer member being slidably mounted over said inner member and having an opening positioned in one face of said outer member; a tension means positioned on the interior side of said face of said outer member containing said opening wherein: the tension force in said tension means is directed away from said outer member toward said inner member for positivelyengaging the toothed rack of said inner member, disengagement means affixed to said tension means and passing through said opening in said outer member for disengaging said tension means from said rack.

2. A device according to claim 1 wherein said tension means is a flat springpawl.

3. A device according to claim 1 wherein said outer member is a rectangular sleeve having an opening positioned in one face of said sleeve, a tension pawl attached to said inner faceof said outer sleeve, said pawl under a tension force directed away from the face of said outer sleeve to which said pawl is attached, disengagement means affixed to said pawl and passing through said opening.

4. A device according to claim 3 wherein said inner member is a rectangular sleeve having a ratchet rack afiixed thereto with the teeth of said rack inclined downwardly and outwardly and said pawl affixed to said outer sleeve is a flat spring which extends upwardly at an angle substantially similar to the inclination of the teeth of said ratchet rack.

- References Cited UNITED STATES PATENTS 898,973 9/1908 Curran 182205 REINALDO P. MACHADO, Primary Examiner

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