US2889099A - Ladder construction - Google Patents

Description

June 2, 1959 w, PULKIN 7 2,889,099

LADDER CONSTRUCTION Filed April 1, 1955 ATTORNEY United States Patent Ofilice Patented June 2, 1 959 LADDER 'C ONSTRUCTION Application April 1, 1955, Serial No. 498,614

1 Claim. c1. 228-31) This invention is a ladder construction, the primary object of which is to provide means whereby the ladder, whether an ordinary scaling ladder, a scaifolding ladder or a step ladder, may be so constructed as to provide automatic leveling means in order that the ladder may be solidly or firmly erected and maintained on uneven surfaces.

A further object of the invention is to provide means of simple construction for attachment either to a scaling ladder or a step ladder and which involves a simplified supporting leg capable of swinging movements laterally of the ladder in order to compensate for unevenness in the ground or supporting surface.

A still further object of the invention is to provide an attachment seeking these improved functions which is of extremely simple construction, which may be readily applied to ladders of standard construction and now in use, which automatically adjusts itself to uneven or undulating surfaces, which enables the ladder to be readily stored away or shipped in a minimum of space, which is simple and yet positive in its operations, which may be manufactured and marketed at extremely low cost, and which will adequately accomplish the objects set forth.

With the foregoing objects in view, together with others which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts, all as will be more fully described hereinafter, illustrated in the drawings, and particularly pointed out in the claim.

In the drawing:

Fig. l is a rear elevation of a step ladder equipped with the leveling means constructed in accordance with the invention,

Fig. 2 is a side elevation of the device as shown in Fig. 1,

Fig. 3 is a fragmentary detail view showing means whereby the spread of the ladder may be controlled,

Fig. 4 is a perspective view of an attachment involving my invention as constructed for use in connection with scale or extension ladders,

Fig. 5 is a rear elevation of the lower end of a scaling ladder and illustrating the device as in Fig. 4 applied thereto, and

Fig. 6 is a fragmentary sectional view, on a slightly enlarged scale, taken upon line 6-6 of Fig. 4.

The attachment of my invention, as heretofore stated, is constructed for attachment either to the well known step ladder or the standard scale or scaffolding ladder, the structure of the attachment being precisely the same with either type of ladder, the only difference being the manher in which the attachment is applied.

The step ladder as shown in Figs. 1 and 2 comprises the usual spaced stiles 10 connected at the top by the platform 11 and having spaced rungs or steps 12. It will be understood that these stiles constitute the supporting legs for the structure. The step ladder brace comprises a pair of spaced leg members or struts 13 pivoted as at 14 in any suitable manner to the upper ends of the stiles i from their lower converging ends.

10. These struts are straight and extend downwardly in converging relationship from their pivotal connections 14 with the stiles, being rigidly secured together in any suitable manner at their lower ends. It will be observed that the meeting ends of the depending struts lie in. the longi tudinal center of the ladder structure.

The leveling attachment comprises a frame including legs 15 of equal length secured together in converging relationship at one end and pivoted at such end as at 16 to a plate or other support 17 connecting the struts inwardly This pivot 16 is disposed in the longitudinal center of the brace. The legs 15 are connected by a transverse stirrup 18 having therein an arcuate slot 19 concentric with the pivot 16. This stirrup 18 is disposed in substantially the same plane with the meeting lower ends of the struts 13, and a bolt or stud 20 secured at one end to the said meeting ends of the struts 13 extends through the arcuate slot 19. A threaded nut 21 is engaged with the opposite end of the bolt or stud 20. It will be understood that when the nut 21 is loosened, the auxiliary unit or frame is capable of freely swinging laterally of the ladder on its pivot 16, while when the nut 21 is tightened the frame of the auxiliary legs will be held securely against such swinging movement. It will be observed that the legs 15 diverge from their pivotal connection 16 to provide spaced apart feet which lie within the lateral edges of the ladder itself.

In order tohold the ladder brace with the attachment applied thereto in any desired angular relationship with the stiles 10, a chain 22 may be secured at one end as at 23 to the lower end of the struts 13 and passes through a keyhole opening 24 in an angular plate 25 .secured to one of the steps of the ladder.

In the modified construction of the attachment as shown in Figs. 4 to 6 inclusive, the auxiliary legs are pivotally connected as at 26 to a plate 27 having spaced openings 28 near its outer ends to receive the legs of U bolts 29 to receive the stiles 30 of the ordinary scaling or extension ladder. A similar plate 31 is arranged in spaced parallelism with the plate 27 and is also provided at its outer ends with the openings 28 to receive the legs of the U bolts 29. The legs 15 of the attachment are connected by the stirrup 18 which is equipped with the arcuate slot 19 concentric with the pivot 26 and receiving the threaded stud 20 equipped with a wing nut indicated at 32.

In operating the auxiliary support for the step ladder, the nut 21 will be loosened to permit free swinging movement of the auxiliary leg, and it will be understood that the lower ends of the feet of these legs lie ordinarily in the same plane with the lower ends of the stiles 10. When unevenness in the ground is encountered, the attachment will automatically adjust itself to such undulations as shown by the dotted lines in Fig. 1. In most circumstances, it will be unnecessary to tighten the nut 21, as the weight of the ladder as well as any occupant thereof, will tend to maintain the attachment in firm position with its legs seated upon the undulating surface. However, should it be desired to fix the attachment against any accidental side movement, tightening of the nut 21 will bring about this result. It will be observed that the weight of the ladder, augmented by the weight of an occupant, will be directed down the converging stiles 13 in the longitudinal center of the ladder, from which this weight will be transmitted through the pivot 16 as well as the stud 20 to the auxiliary leg structure or frame. By constructing the auxiliary frame with its legs within the lateral lines of the ladder stiles, it will be apparent that the ladder may be folded either for shipment or for storage purposes without offering any obstacle or cumbersome structure, much the same as may the ordinary step ladder now in use.

In the modified form shown in Figs. 4 to 6 inclusive,

the bars 27 and 31 are attached to the ladder stiles 30 by threadedends of: the. U bolts and tightened. The, spaced. bars; 2,7 31 are thus rigidly secured, to the ladder-stiles,

and, itis; preferred that in making this attachment the U, bolts either of the upper or lower cross barsv be engaged immediately below one of the ladder rungs, as. In,

indicated at 33 to additionally stabilize the structure. applying this attachment to the ladder, the lower ends or feet of the diverging legs; 15'Wlll be disposed beyond the lower end; of the ladder so, as to constitute the support In all other respects, the construction is,

for the same. the same as; that described in connection withv the step ladder. In this instance, it will be observed, the-pivotal connection 26 ofthe legs 15 will be disposed in the longitudinal center. of the ladder so that the weight will be equally delivered to both of the spaced legs 15.

It will be observed, particularly with reference to Fig. 1, that the arcuate slot 19 is of such length that when the attachment is swung upon its pivot 16 to the limit of its movement either to the right or the left, neither of the legs 15 will pass beyondv a longitudinal center through the pivots 16 and 20, it is obvious, therefore, that this limitation of swinging movement overcomes the possibility of the ladder being defectively erected or adjusted.

The material of which the ladder and the attachment is made is of little importance, as it is obvious that the inventive idea may be readily carried out with ladders made of wood, metal or a combination of both. It may be necessary, in, some instances, to redesign or make minor alterations in the construction and assemblage of the parts inorder to adapt the inventive idea to ladders formed of different materials, but it is apparent that such variations can well be carried out without departing from the spirit of the invention.

I claim:

An attachment for a ladder having spaced substantially parallel stiles, comprising a pair of plates, means to secure said plates at' their ends to the stiles of said ladder in spaced parallelism transversely thereof, an auxiliary leg comprising a pair of bars united at one endand arranged in diverging relationship, a pivot pin securing the meeting ends'of said: bars to one of said plates midway between said stiles, a stirrup connecting said diverging legs in the same planewith the other of said plates and overlying the latter, said stirrup having an arcuate slot therein concentric with said pivot pin, an anchoring pin secured to said other plate and extending through said 7 slot, and a nut threaded upon the opposite end of said pin.

ReferencesCited'in the file of this patent UNITED STATES PATENTS 32,569 Knox June 18, 1861 455,973 Parr et al. July 14, 1891 1,471,290 Stevens Oct. 16, 1923 1,982,172 Myers Nov. 27, 1934 2,397,468 Cail Apr. 2, 1946 FOREIGN PATENTS 124,419 Australia June 12,1947

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