US2971602A - Ladder leg levelling device - Google Patents

Description

Feb- 14, 1961 c. A. WES T 7 LADDER LEG LEVELLING DEVICE Filed Oct. 6, 1958 llll JNVEN TOR.

BVWVM United States Patent Ofiice 2,971,602 Patented Feb. 14, 1961 2 Claims. (Cl. 182-200) This invention relates to devices for automatically leveling a ladder relative to an uneven support base.

Leveling devices have been employed heretofore to facilitate the leveling of ladders relative to an uneven support, however, several devices of the prior art have not proved entirely satisfactory inasmuch as they are complicated in design and construction, expensive to manufacture, and difficult to use.

With the foregoing in view, the primary object of the invention is to provide a leveling device for ladders which is simple in design and construction, inexpensive to manufacture and easy to use.

An object of the invention is to provide substantially concentric arch and bridge members having a brake pad disposed therebetween at a high shear cam angle to lock the bridge member in the adjusted relationship upon the weight of the ladder and the load being placed thereon.

An object of the invention is to provide means for adjustably holding the bridge member relative to the arch member so that the bridge member can move automatically relative to the unevenness of the ground.

An object of the invention is to provide a frame having a transverse cross member equipped with a half round longitudinal socket groove for receiving the bottom rung of the ladder in supporting relationship.

An object of the invention is to provide quick-acting mounting and dismounting means for the device relative to the ladder.

These and other objects of the invention will become apparent by reference to the following description of an automatic ladder leveling device embodying the invention taken in connection with accompanying drawing in which:

Fig. 1 is a elevational view of the device mounted on a ladder.

Fig. 2 is an enlarged cross-sectional view of Fig. 1 taken on line 22 thereof showing the construction in more detail.

Fig. 3 is an enlarged cross-sectional view of Fig. 1 taken on line 33 thereof showing the brake pad between the arch and bridge members.

Fig. 4 is an enlarged cross-sectional view of Fig. 1 taken on line 44 thereof showing the construction of the arcuate feet; and

Fig. 5 is a cross-sectional view of optional connecting means of between the side members of the device and the ladder rails.

Referring now to the drawing wherein like numerals refer to like and corresponding parts throughout the several views, the ladder leveling device disclosed therein to illustrate the invention comprises a frame adapted to fit between the ladder rails 11 and 12 and below the bottom rung 13 in supporting relationship thereto with the frame being secured to the ladder rails as by bolts 14. The arcuate bridge member 15 is slidably movable relative to the arch member 16 on the frame 10 and friction pads 17 are disposed at either side of the high shear camming angle to lock the bridge member in its adjusted relationship relative to the arch member when the weight of the ladder and load is placed thereon.

More particularly, the frame comprises a cross member 20 having a longitudinal half round groove 21 formed therein for receiving the bottom rung 13 in a socketed relationship so as to provide support for the ladder via the bottom rung and to prevent the device from moving or pivoting on the bolts 14; side members 23 and 24 depend from the cross member 20 and lie adjacent the ladder rail 11 and 12 respectively and at the lower ends connect to the arch member 16 which is connected to the cross member 20 via the strut 22.

The arch members are provided with paired flanges 25 and 26 at either end thereof adjacent the side memthe slot is wider than the diameter of the pin 29 to permit the bridge member 15 moving radially relative to the arch member 16. The bridge member 15 is provided with feet 31 and 32 at either end thereof having an arcuate conformation so that in the angular adjustment of the bridge member 15 relative to the vertical plain of the ladder that the feet 31 and 32 will contact 'the ground 33 on radii substantially parallel to the axis of the rails 11 and 12. p

The bolts 14 of Fig. 1 may be replaced by the spring pressed device of Fig. 5 wherein the clip 40 is welded to the sides 23 and 24 and has an apcrtured head 41 for receiving the shank 42 of the dowel 43 it is to be noted that the spring 44 resiliently urges the dowel 43 to the left into the area of the ladder rail of 11 with further movement being prevented by the cap 45 contacting the head 41 of. the clip 40; the dowel 43 may be extracted by using a nail on the outside of the ladder to move the dowel 43 against the spring 44 out of the rail 11 area to remove the device from the ladder.

In operation the frame 10 is inserted between the rails 11 and 12, and in the event the spring pressed dowel 43 is employed, the dowels are pressed backwardly against the spring as by the users fingers and then the frame 10 adjusted until the dowels enter the rail apertures 50 and the device is then fixedly mounted with the cross member 20 receiving the rung 13 via the longitudinal groove 21 so that the device is secured and locked on the ladder in fixed relationship thereto.

Upon the user lifting the ladder by the side rails 11 and 12, the bridge member 15 drops downwardly due to the space in the slot surrounding the connecting pin 29 so that the bridge member 15 drops out of contact with the brake pad 17 so that when the user vertically adjusts the ladder relative to the ground and contacts the feet 31 and 32 thereon, the bridge member 15 initially will move angularly relative to the arch member 16 to position both feet 31 and 32 on the support regardless of the unevenness thereof whereupon by further downward movement of the ladder and arch member 16 relative to the bridge member 15, the brake pads 17 are brought into contact with the bridge member 15 and the ladder weight and load thereon drives the brake pads 17 downwardly at a high shear cam angle relative to the bridge member 15 locking the movement of the ladder and the bridge member against relative angular movement thereby positioning the ladder fixedly as adjusted to its vertical condition. 7

Obviously, the ladder can be picked up and moved to other positions where the ground has, difierent contours and the bridge member 15 will automatically move to its proper angular relationship and when the ladder is vertically correctly positioned and allowed to rest upon the bridge member via the arch member 16, the device will automatically lock as adjusted.

The inventive leveling device with these features con-1 stitutes a compact, durable, and neat appearing mechanism easily placed on a ladder and easily used to a vertically positioned ladder and locking it in position automatically.

Although the single embodiment of the invention has been shown and described in detail, it is obvious many 'changes'rnay be made in size, shape, detail, and arrange ment of the'various elements of the invention within the scope of the appended claims.

I claim: I 1; The combination of a ladder and a supporting base at the center thereof and at either end thereof forming a channel with said arch member for receiving an arcuate bridge member, an arcuate bridge member disposed con- I arch and bridge members when the ladder and load bears leveling device compressing a' ladder having side rails and interconnecting rungs between the rails including a bottom rung spaced above the bottom ends of said rails and bolt apertures in said rails below said bottom rung and a leveling device having a frame including a crossmember disposed below said bottom rung having a longitudinal socket half round in cross-section receiving and contacting said bottom rung in supporting relationship,

7 side members at their upperends connected to said cross a said bridge member via said pads; said bridge member dropping out of engagement with said pads when said ladder and load are lifted upwardly to permit relative angular movement of said bridge, member to said arch member said bridge member arcuate slot being larger in width than said bolt diameter to permit radial inward movement to lock in position and outward movement of said bridge member relative to said arch member to unlock for adjusting movement. a

2. In a device as set forth in claim 1, arcuate bottoms on said feet for contacting the ground on radii parallel to said ladder rails.

References Cited in the file of this patent UNITED STATES PATENTS 952,836 McCombie Mar; 22, 1910 973,509 lson Oct. 25, 1910 "1,088,167 Osterhoudt Feb. 24, 1914 1,424,934 Paterson Aug. 8, 1922 1,780,386 Harrison Nov. 4,1930 2,639,853 Pierce May 26, 1953

Images