US2608336A - Adjustable ladder stilt - Google Patents

Description

Aug. 26, 1952 DOLE 2,608,336

ADJUSTABLE LADDER STILT Filed March 11, 1950 INVENTOR. LESL IE c. 001.5

HIS ATTORNEYS.

Patented Aug. 26, 1952 IZIUNITED STATES PATENT OFFICE.-

. i l l 2,608,336

ADJUSTABLE LADDER STILT Leslie 0. Dole, Hopatcong, N. J. Application March 11, 1950, Serial No. 149,177 l 2 Claims.

,I'I'his invention relates ,to improvements in extensions for the Regent ladders to facilitate their use on uneven ground or other sup-ports.

Several different types of ladder leg extensions have been devised heretofore for use either with conventional ladders or with step ladders. These prior ladder leg extensions have not been universally usable, that is, an extension constructed for one ladder cannot be used readily with another. type of ladder having legs of different cross-sectional dimensions. Moreover, the prior ladder leg extensions have not had adequate clamping means to assure the rigidity of the extension so that with most of the prior extensions, some tilting or slipping of the extension can take place upon the application of vertical or lateral loads to the ladder. For that reason, the prior devices have given a feeling of instability to the ladder and generally have not been all that might be-desired. I r

The present invention comprises an extension provided with a clamping member of such nature that the extension can be used with substantially any kind of ladder or step ladder having leg thicknesses varying from an inch to an inch and three-eighths or even thicker and of varying widths. Also, the new ladder extension has a novel clamping arrangement which can be seated tightly against the ladder leg to clamp the extension in position and which clamps more strongly as weight is applied to the ladder so that slippage of the extension is effectively prevented under all conditions.

For a better understanding of the present invention, reference may be had to the accompanying drawings, in which:

Fig, l is a perspective view of a portion of the ladder showing the extension embodying the present invention connected to one leg thereof;

Fig. 2 is a view in side elevation of the new ladder leg extension shown attached to a portion of a leg of a ladder;

Fig. 3 is a view in cross-section taken on line 3-3 of Fig. 2; and

Fig. 4 is a view taken on line 4-4 of Fig. 3.

A typical form of ladder leg extension embodying the invention consists of an elongated barlike member or shank I0 adapted to fit against the edge or back of the leg I! of the ladder l2 to permit the ladder to be used on uneven ground or floors. The shank I0 is provided with a rightangularly related foot portion l3 of sufiicient length and width to afford an adequate footing on the ground.

The shank I0 is provided with apalr or semimeans of a suitable fastening device such as a nib 8 at the outer end of the arm 16% to slip through slots Ma and 15a in bearings I41 and 15 thus insuring that the clamp member carrbe easily changed from one bearing to the other or from one side of the shank to the other so that the shank orbar can be used oneitherleg of the ladder. The slots Ma and [5a, as shown in Fig. 4, are arranged so that'when themember l! is. in clamping position, the nib' or tooth lfi is out of alignment with the slots to prevent accidental release cf the member I"! irom'the shank.

The base 19 of the U-shaped member ll extends generally perpendicular to the extensionfor shank l0 andits outer ai'm fiilextendsgenerally parallelto the "arm 16. The arm 20] is pro vided with an enlargement 2| which is internally threaded to receive a clamping screw 22 having a head 23 on its outer end to facilitate its rotationn The inner end of the screw 22 carries a rigid, concavo-convex plate 24 which is rotatably mounted on the end of the screw 22 in any desired way, as for example, by swaging over the end of the screw. The plate 24 has a pair of extensions 24a and 23b to engage opposite sides of the base 19 of the member I! to prevent the plate from rotating with the screw 22.

The opposing face 25 of the shank in also has a concave curvature of about the same radius as the curvature of the opposing face of the clamping member 24. By providing such curved surfaces or faces on the clamping plate 24 and the shank ll], these elements will suitably engage ladder legs of varying thickness as shown in full and in dotted lines in Fig. 3 and prevent twisting of the extension as a whole relative to the ladder leg I i.

In use, the U-shaped member I"! can be connected to the shank [B by inserting the arm 16 in either of the bearing bosses it or l5, bearing l5 being commonly used. The bearing M is used for the utmost extension of the stilt. With the ladder adjusted so the rungs are horizontal, the shank :0 may be adjusted to bring its foot [3 into contact with the ground or other supporting surface and the clamping screw 22 is then tight.- ened to clamp the leg I i firmly between the surface 25 and the clamping member 24. Ordinarily, the clamping pressure will be suficient to retain exten ion. V

the extension in fixed relation to the ladder leg ll. However, if the ladder is formed of hard, smooth wood or metal or the clamping screw only slightly tightened, the ladder leg may have some tendency to slip. Such slippage is prevented by the pivotal movement of the clamping member l1. This pivoting movement draws the clamping plate 24 toward the shank It) so that any tendency of the leg to slip down relative to the shank I!) can result only in an increase in the resistance to slippage.

It will be understood that the clamp base l9 should be placed on the outer side of the ladder leg so that the ladder rungs will not interfere With vertical adjustment of the stilt.

The extension described above is useful with and fits many different types of ladders. It also is convenient to transport and store because the V U-shaped member I! or members can be removed readily or folded down against the shank I0 thereby reducing the space occupied by the It will be understood that while one size with aniextencsion shank 24 inches long will serve practically every purpose, the extension may be made .invarious sizes and of various types of materials, for example, either wrought or malleable steel, fluetile'iron, aluminum, magnesium or alloys of aluminum or magnesium, etc. and it may be made in larger size for especially heavy ladders. There- Iore; the form of extension disclosed herein should be considered as illustrative and not as limiting thefscfope of the following claims;

bl-aim? fICAnTextension leg attachment for a ladder comprising an elongated extension member having a from side" engageable with a ladder le'g, a substantially U'-shaped bracket havi'ngone arm extending transversely through said member and another"substantially parallel arm in .fro'nt of sa dmemb r, means on said member'r'o'tatably receiving said one arm to permit swinging movement of said bracket around the axis of said one arm, a clamping screw adjustably mounted in said another arm for movement toward and away from said member, and means on the inner end of said screw to engage said ladder leg and clamp it against said front side of said member.

2. An extension leg attachment for a ladder comprising an elongated extension member having a transversely concave front surface engageable with a ladder leg, said extensionmember having at least" one hole extending transversely therethrough behind said front surface, a rigid, substantially U-shaped bracket having one arm rotatably mounted in said hole and another substantially parallel arm in front of said front surface, means detachably retaining said one arm in said hole to enable said bracket to be secured to and detachedfrom said member and said one arm to be inserted into said hole from either end cream hole, and a clamping screw adjustably mounted in said other arm for movement t ward and away from said member to clampfsadmem; ber to and release itfrom a ladder leg.

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