US2656087A - Ladder construction - Google Patents

Description

Oct. 20, 1953 w, SHARRQCK 2,656,087

LADDER CONSTRUCTION Filed April 4, 1952 2 Sheets-Sheet l INVENTOR.

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Oct. 20, 1953 w. SHARROCK 2,656,087

LADDER CONSTRUCTION Filed April 4, 1952 2 Sheets-Sheet 2 IN V EN TOR.

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Patented Oct. 20, 1953 UNITED TES TENT OFFIQE LADDER CONSTRUCTION William Sharrock, Beverly, Mass.

Application April 4. 1952, Serial No. 280,543

2 Claims. 1

The present invention relates to ladder constructions and more particularly to an improved rung assembly therefor.

Among the objects of the present invention is to provide an improved rung for ladders which is characterized by its increased strength, economical cost, ease of installation and its ability to strengthen and reinforce the ladder to an extent which permits its use in supporting heavy staging without danger of failure.

Another object of the present invention is to provide an improved rung of such a construction that ladders may be sold in knock-down condition and readily assembled by the purchaser.

The present invention contemplates a novel rung assembly for ladders which is in the form of a replacement unit for use in substitution of old rungs of ladders which have become worn to the point of being unsafe or completely unusable because of structural failure.

More particularly the invention comprehends a rung assembly as immediately hereinabove described which may be readily and easily substituted as a replacement rung for the rungs of the conventional type ladder without disassembling the same.

Still another object of the present invention is to provide an improved rung assembly of multipart construction in which the parts are formed in such a manner as to assure proper resistance to heavy loads and in which the same are interlocked with the side rails of the ladder to prevent the side rails from spreading apart and to greatly reduce lateral swaying of the ladder.

Other objects, features, capabilities and advantages are comprehended by the invention as will later app-ear and as are inherently possessed thereby.

The present application is a continuation in part of application Serial No. 100,347, filed June 21, 1949, now abandoned.

Referring to the drawings:

Figure l is a plan view of a ladder embodying the present invention;

Figure 2 is an enlarged fragmentary view in elevation of a section of a ladder embodying an improved rung assembly made in accordance with the present invention, parts thereof being shown in section to disclose the structure more in detail;

Figure 3 is an enlarged fragmentary view in end elevation of the structure shown in Figure 2 of the drawings;

Figure 4 is an enlarged view partly in section and partly in elevation of the end flange for the rung positioning member;

Figure 5' is an enlarged fragmentary view in section disclosin an alternative form of construction for the rung assembly made in accordance with the present invention;

Figure 6 is an enlarged fragmentary view in end elevation of the structure shown in Figure 5 of the drawings;

Figure 7 is a cross-sectional view taken in the plane represented by line l'? of Figure 5 of the drawings;

Figure 8 is an enlarged sectional view of the rung assembly shown in Figure 2 of the drawings and disclosing more particularly a step in assembling the same with the side rails of a ladder;

Figure 9 is a view similar to Figure 8 of the drawings disclosing the relation of the parts of the rung as the assembly thereof progresses;

Figure 10 is an enlarged fragmentary front view of a ladder showing a further modified rung constructicn therefor;

Figure 11 is an enlarged fragmentary vertical cross-sectional view showing the rung construction for the ladder shown in Figure 10 of the drawings;

Figure 12 is an enlarged fragmentary end view of the ladder shown in Figure 10 of the drawings; and

Figure 13 is a viewin cross section taken in the plane represented by line [3-43 of Figure 11 of the drawings.

Referring now more in detail to the drawings, one form of rung assembly made in accordance with the present invention and particularly adapted for use as a replacement part for a ladder as shown in Figure 1 of the drawings is disclosed as comprising an outer sheath 2 of a length defined by the distance between the inner faces of the side rails 4 and 6, a core 8, and a rail securing member iii. The core 8 is of a length corresponding to the distance between the outer faces of the rails t and 6 and the same is mounted adjacent its ends in the openings l2 and M of the rails i and 6, respectively. The rail securing member is in the form of a metal tie rod, non-circular in cross-section and having laterally extending flanges I6 and i=8 at the ends thereof adapted to engage the outer faces of the rails 4 and 6, respectively, for positioning these rails and interlocking the rung assembly therewith.- The flanges I6 and I8 have their inner faces spaced apart a distance for proper alignment of the rails 4 and 6 and are formed with teeth 2!! thereon adapted to imbed themselves in the rails 4 and 8 to prevent the tie member Hi from turning relative to the rails. The tie member Ill throughout its length is received Within the radial groove 22 formed in the periphery of the core 8 which positions the core 8 and prevents rotation thereof relative to the member ID and the rails 4 and 6. The outer sheath 2 is disposed in substantial end abutting relation with the inner face of each of the rails 4 and 6, thus serving as a spacing element for the rails. This outer sheath completely embraces and encloses the core 8 and the tie member ID to provide a complete rung assembly for the ladder.

During the assembling of the rung in a ladder an adhesive or cementitious material may be applied to the periphery of the core 8 and/or the. inner surface of the outer sheath 2 which is. adapted to harden or set for holding the outer sheath against rotation relative to. the core 8 and to hold the core 8 against lateral displace.- ment with respect to the rails 4 and 6. Any other suitable securing means may be provided for effectin this unitary type of structure whereby the parts of the rung assembly are positioned with respect to the rails.

The present invention contemplates an im proved type of rung assembly which lends itself to the production of ladders for sale in knockdown condition, which may be readily assembled by the purchaser. The embodiment of the invention disclosed in Figures 2, 3 and 4 may be used in this type of ladder construction, but in a new ladder, the embodiments of the invention disclosed in Figures 5-7 and -13 are preferably used. The rung assembly disclosed in Figures 5-7 and identified generally by the reference character 24 is of substantially the same construction as the rung assembly shown in Figures 2, 3 and 4 of the drawings. In constructing a new ladder, however, it is relatively simple procedure to form the rails 4 and 6 with recesses 26 extending laterally of the openings I2 and I4 and adapted to receive the laterally extending flange 28 at the ends of the rod 39. These recesses are of a depth conformin to the thickness of the flanges 28 so that when the ladder is completed in its final form, the said flanges are flush with the outer surface of the rails 4 and 6.

The rung construction shown in Figures 10 to 13, inclusive, conforms in a good many respects to the embodiment shown in Figures 5, 6 and '7, and comprises the rails 4 and 6, having the longitudinal securing member ID extending through the openings I2 and I4 therein and formed with the flanges 32 and 34 received in recesses, such as 36, provided in the outer faces of the rails '4 and 6. A core 38 is provided having a groove 48' adapted to embrace the longitudinal securing member ID and which is enclosed by the sheath 42 having end abutting relation with the inner faces of the rails 4 and 6. The sheath 42 is provided with a groove 44 adapted to embrace the elongated securing or positioning member ID. It will thus be seen that when the elements of this modification are assembled in the manner hereinafter more fully described, the elements are held in their assembled relation by virtue of the flanges 32 and 34 which prevent outward bowing of the rail members 4 and '6, and by the sheath 42 which prevents inward movement of the rails with respect to one another. By providing the sheath 42' with the groove 44 which embraces the elongated .positioning member ID, the sheath is prevented from rotating. Thus it will be seen that the use of adhesive which is preferably used in the first two embodiments between the sheath and core is eliminated.

The present invention contemplates the use of at least one of the rail assemblies herein disclosed adjacent each end of the ladder of the knockdown type, it being understood that the remaining rungs may be of the conventional type. The present improved rung assemblies are used to tie the entire ladder assembly together as a unitary structure, although the invention is of such scope as to comprehend the use of rungs of the type herein disclosed throughout the length of the ladder.

The ease and facility with which these rung assemblies may be inserted in place as, for example, a substitute for a worn or broken rung in a conventional type ladder, reference may be made to- Figures 8 and 9 which show a rung assembly of the type shown in Figures 2, 3 and 4 of the drawings, although the manner of assembling the form shown in Figures 5, 6 and 7, and 10-13 is identical. In assembling the rung, the, outer sheath 2- is first positioned between the rails 4 and 6, after which the tie rod II] is inserted through one of the openings I2 or I4 of the rails through the outer sheath 2 and through the oppositely disposed opening of the opposite rail. The end flanges I6 and I 8 are then positioned with respect to the rails 4 and 6 with the tie member II] in engagement with the walls forming the openings I2 and I4, as more particularly shown in Figure 8 of the drawings. The'core 8 is then inserted into one of the openings I2 or I4 of the side rails as illustrated in Figure 8 so that the recess 22 is in alignment with the rod [0 after which, the sheath 2 is properly aligned with the openings I2 and I4 as the core 8 is moved transversely with respect to the rails. This introduction of the core 8 within the outer shaft 2 is illustrated in Figure 9 of the drawings which shows the core in its intermediate position. The core 8 is then moved laterally or transversely with respect to the railsuntil such time as the ends are in alignment with the outer faces of said rails. In the assembly of the ladder rung shown in Figures 10-13, it is of course understood that the grooves of both the core and outer sheath must be properly aligned with respect to the member. As indicated above, a permanent unitary structure may be formed by applying adhesive or cementitious material between the core 8 and the outer sheath of the embodiments shown in Figures 2, 3 and 4 and Figures 5, 6 and '7 whereby the assembly is fixed in position with respect, to the side rails 4 and 6. In the embodiment shown in Figures 10 to 13, however, the groove in the sheath prevents rotation thereof and, accordingly, no adhesive is necessary.

It will be apparent that the improved rung as herein disclosed may be readily and easily assembled with respect to the side rails as a replacement for worn or broken rungs of the conventional type. Such rung assembly is of such a construction as to withstand the loads imposed thereon by heavy staging and the same is securely interlocked with the side rails to prevent excessive swaying of the'ladder and to prevent outward spreading of the rails 4 and 6, thus lending itself admirably to such use as a substitute or replacement part, although as hereinabove set forth, the invention contemplates the use of such assembly in manufacturing ladders of the knock-down type.

While I have herein described and upon the drawings shown illustrative embodiments of the invention, it is to be understood that the invention is not limited thereto but may comprehend other constructions, arrangements of parts, details and features without departing from the spirit thereof.

It is claimed:

1. In a ladder, the combination of opposed side rails provided with transversely disposed substantially aligned openings, a rung, said rung comprising an outer sheath disposed between said Side rails with its ends abuttin the inner faces of the rails, an elongated member insertable into assembled relation with said side rails through at least one of said openings and said outer sheath and having laterally extending flanges at the ends thereof having shouldered engagement with said side rails at the outside face to hold the same in proper spaced aligned relation and holding said member against rotation relative thereto, and a core having an elongated groove insertable into assembled relation with said side rails through at least one of said openings and said outer sheath when said groove is aligned with said elongated member, the ends of the core extending into the openings in both rails.

2. In a ladder, the combination of opposed side rails provided with transversely disposed substantially aligned openings, a rung, said rung comprising an outer sheath disposed between said side rails with its ends abutting the inner faces of the rails, said sheath having an internal lon- 30 gated member fitting into the internal groove of the sheath member, and a core having an elongated groove insertable into assembled relation with said side rails through at least one of said openings and said outer sheath when said groove is aligned with said elongated member, the ends of the core extending into the openings in both rails.

WILLIAM SHARROCK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 640,645 Fall Jan. 2, 1900 1,051,275 Schreiner Jan. 21, 1913 1,461,952 Walchi July 17, 1923 FOREIGN PATENTS Number Country Date 336,888 Great Britain Oct. 23, 1930 501,557 Great Britain Mar. 1, 1939

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