US2703196A - Converging stile platform ladder - Google Patents

Description

2 Sheets-Sheet l C. F. HANSEN CONVERGING STILE PLATFORM LADDER o 2 HT.

Mmh 1, 1955 Filed May 1, 1952 INVENTOR. Cc/ff mww C. F. HANSEN CONVERGING STILE PLATFORM LADDER March 1, 1955 Filed May 1, 1952 2 Sheets-Sheet 2 I INVENTOR.

Cad/f United States Patent 2,703,196 CONVERGING S TILE PLATFORM LADDER Cecil F. Hansen, La Grange, Ill., assignor to Craft-Bilt Company, Detroit, Mich., a corporation of Michigan Application May 1, 1952, Serial No. 285,355

4 Claims. (Cl. 228-29) The present invention relates to improvements in platform type stepladders and concerns itself more particularly with ladders of this class utilizing front and rear stiles which are wider spread at the bottom than at the top for affording improved stability.

This invention is an improvement upon copending application Serial No. 132,298, filed December 10, 1949, now Patent No. 2,652,967 issued September 22, 1953, and teaches a construction of stepladder utilizing foldable wide tread or platform type rungs in conjunction with front and rear vertical rails or stiles disposed angularly to each other for the purpose of achieving added stability by an increase of spread or footing at the lower extremity.

Stepladders of the type with which the present invention concerns itself customarily range in height from about four to about twelve feet and are used for domestic as well as industrial purposes. In connection with various classes of services which require long periods of standing by the user and considerable stability against swaying, it is important that ladders of this class possess adequate support to assure the users of secure balance and stability even when the user is required to reach or shift weight in side to side respect.

Under such conditions and uses, wide tread platform ladders afford abundant footing support and yet permit the user to vary his position without rendering his security precarious. The wide angular spread affords the necessary lateral displacement to safeguard against overbalancing in the event that the work requires the user to lean or range sidewise beyond the normal facilities of this class of stepladders.

Spreading of the side rails for the purpose of achieving a wide footing base with a narrower top section is a practice manifestly inconsistent with the use of platform treads for reasons which will shortly be explained. Accordingly, it is a principal object of this invention to design a foldable stepladder of the type suitable for household or industrial utility work characterized by its adaptation of foldable platform treads with side rails which possess a definite degree of spread or digelrgence downwardly and outwardly for affording staiity.

Another object of the present invention is to achieve a foldable stepladder having inclined or spreading side rails or stiles connected together by means of foldable transversely extending supporting beams or connectors on which are adapted to rest retractile laterally extending platform treads.

Another object of the present invention is to provide a foldable rail stepladder having inclined side rail or stile elements as well as a plurality of transversely connecting beams at different levels for supporting platform treads, and which permits. of the folding of the transverse or connector beams simultaneously with the folding together of the stiles while said beams are rotated into a vertical position, without encountering obstruction on account of the convergence of the side. rails.

These and other objects of the present invention are achieved by a novel and original foldable stepladder construction in-which a pair of front or tread rails are foldable in respect to a corresponding pair of rear or brace rails so as to assume alternative positions between utility or wide spread spanning condition and non utilityor folded together position. erably regularly spaced levels the two sets of rails are connected together on both sides of the ladder At ditferent and pref-' ice by means of foldable angle metal support brackets or beams the lengths of which increase progressively in a downward direction as the span between the front and rear rail components increases when the ladder is in its utility condition. These pairs of transversely extending brackets each serve the purpose of supporting a platform tread preferably secured to the brackets as by bolting or riveting in such a manner as to permit the platforms to be selectively swung in a rectractile manner so that when a lowermost tread is disposed for service or utility, other brackets above the one may be folded out of the way and thereby afford additional leg room for movement and maneuverability.

Attention is now directed to the accompanying drawings and to the hereinafter following detailed description wherein similar reference characters designate corresponding parts throughout in which:

Fig. l is a front elevational view of a spread stile stepladder in folded condition having embodied therein various features of the present invention,

Fig. 2 is a transverse sectional view on an enlarged scale taken approximately on the line 2-2 of Fig. 1 showing the detail of construction and with portions broken away,

Fig. 3 is a fragmentary plan view of a stepladder constzructed in accordance with the features of Figs. l and Fig. 4 is an enlarged sectional detail view taken approximately on line 4-4 of Fig. 2,

Fig: 5 is an enlarged sectional detail view taken approximately on line 55 of Fig. 2,

Fig. 6 is an enlarged fragmentary sectional view taken approximately on line 66 of Fig. 5 and,

Fig. 7 is a sectional view similar to Fig. 4 but featuring a modified pivot bracket construction.

A pair of frontal or tread stiles 11 and 12 are secured as by bolting or riveting to platform brackets 13 as at 15, so as to have an identical forward slope as best revealed by the illustration in Fig. 2, and so as to flare downwardly and outwardly to a slight angular extent as best illustrated in Fig. l where the stiles 11 and 12 are shown terminating as at 15 with foot extremities.

The two brackets 13, Fig. 3 may be simple channel elements having secured upon them as by rivets 16, the top platform boards 17 and 18 of which board 17 is shown cut away as at 19, to afford a degree of vertical clearance to the use of the second tread.

Near the rear end of the brackets 13 there are carried pivot'elements 21 from which are hung the rear or brace stiles 22 and 23. These members are likewise spread after the manner of the frontal stiles 11 and the rear or brace stiles are usually somewhat lighter cross sectionally than the tread stiles.

The angular inclination which is embodied into the frontal and rear stiles viewable in Fig. 1 will be referred to hereinafter as the spread. It is considered desirable and advantageous to provide ladders of this class with a substantial degree of spread because it is recognized that this factor improves the stability of the ladder, and consequently improves the safety to the operator using such ladders in various types of work.

In narrow rung stepladders of the type which are permanently anchored between the front stiles, no particular problem is encountered because of the spread factor other than requiring that the several rungs in an ascending order be progressively shorter in conformity with the angular disposition of the two frontal stiles one with regard to the other.

' definite problem is encountered because of the lateral In platform tread stepladders, however, av

this would overcome the difliculty. However, since these platforms, to be retractile, require to be supported on side rails as disclosed and explained in the above referred to copending application, the factor of the lateral d1s placement may not be so'easily reconciled. It is feasible, of course, that the several spaced horizontal support brackets or beams may be bent or so shaped" that upon being folded together after the manner'shown in Fig. 1 their uppermost extremities will be closer together and in this way avoid interfering with the slope of the stiles. This is not a practical nor desirable solution from several viewpoints, and for this reason the present invention proposes a novel type of bracket mounting from which the foldable brackets may be pivotally supported in such a manner that without bending or other misalignment of their longitudinal portions, they may still constitute n'o' conflict with the convergence characteristics of the stiles by reason of the described spread.

Referring now more particularly to the ShOWlllg in Figs. 1 and 2, attention is directed to the three levels of support brackets or beams generally designated 25, 26 and 27. These support brackets are provided in pairs at each level, one for each side of the ladder, and each bracket is comprised of two angle members of which at level 26 the foremost one is designated 28 and the rearmost one, 29.

characteristically, the foremost bracket, such as the one designated 28 is constructed significantly longer than its related rearmost brackets so that there is a length of overhang 31 which serves the purpose of rigidifying the bracket when it is in its extended position. Thus it will constitute a sturdy support member or beam for its platform tread comprised, in this case, of the stationary tread board 32 and the swingable or retractile tread boards 33 and 34 when the latter are disposed in their utility or solid outline position, Fig. 2. g Y

The two beam elements 28 and 29 are pivoted together as at 35 so that when the rear stiles are swung toward the frontal stiles as for folding the ladder into its storage condition the two bracket elements 28 and 29 will move upwardly, each pivoting on its respective pivotal extremity 36 and 37. When these pivots, 36 and 37, are disposed in the known manner, close to their related rails 11 and 22, respectively, this movement into a folded condition is not feasible beyond a point at which the bracket elements conflict with the convergence of the side rails due to the slope characteristic of their spread. For the purpose of avoiding this obstruction, the extremities of the brackets 28 and 29 are pivoted instead as at 38 and 39, Figs. 4 and S, in offset portions of discrepancy correcting pivotal bracket members formed of strap stock material and shaped after the manner shown in Figs. 4 and or after that shown in Fig. 7. Each hinge bracket is formed with a perpendicular strut element 39 and an angularly disposed strut element 41 which connects the offset portion 38 with the flush lug extremities 42 and 43 that are bolted as at 44 to their respective side rails.

The distance of offset respecting the pivotal projections 38 from their respective rails is sufficient that upon folding of the brace elements 28 and 29 into their dormant positions, Fig. l, the uppermost extremities thereof will clear the converging sections of the respective frontal and rear rails without requiring them to be bent or in any way distorted for this purpose.

In order that the folding of the several connector brackets 25 and 26 and 27 may be accomplished with utmost facility, each pivotal junction 35 is preferably equipped with a tensioning washer or disk 45, Fig. 6, so that the disposition of the beam components 28 and 29 1n any angular position will be self-retaining and frictionally withheld against inadvertent gravitational or other effects toward returning, until all of the beams have been folded and the frontal and rear rails brought together into their folded condition. The pivotal elements are shown to be rivets with semi-spherical heads and swag'ed rivet extremities although it is to be understoodthat where preferred, bolts or other types of securing elements may be used instead.

While the present invention has been explained and described with reference to specifically contemplated em bodiments, it will be understood,nevertheless, that numerous modifications and variations are susceptible of being incorporated without departing from the essential spirit or scope thereof. Accordingly, it is not intended that an understanding of this invention be restricted to the particular illustrations in the accompanying drawings nor to the language employed in the foregoing description except as indicated in the hereunto appended claims.

I claim:

1, A foldable ladder comprised of front and rear sidewardly flaring stiles foldable toward and away from each other, a plurality of pairs of foldable span brackets connecting said front and rear stiles at different levels, and means for pivotally supporting the extremities of said span brackets at their connections with said stiles so that when folded, their intermediate portions will not conflict with said stiles because of said sideward flare which comprises pivot brackets formed of strap stock with portions intermediate securing ends inwardly off-set with a horizontally jutting section connecting one side of said portions with one of its ends and a diagonally extending section connecting the other side of said off-set portion with its other end.

2. In a foldable platform stepladder, a pair of tread stiles comprising the frontal section of a foldable ladder, a top platform across the upper extremity of said tread stiles, a bottom tread secured between said stiles at a lower level and being longer than said top platform whereby to dispose said stiles in a downwardly diverging spread, a pair of prop stiles similarly spread and pivoted at said top platform so as to be foldable toward and away from said tread stiles and comprising the rear section of said ladder, a plurality of pairs of span brackets at spaced levels connected at their ends with said tread and prop stiles for assuming folded and extended positions in accordance with the folded and extended relationship of said tread with prop stiles, and pivot elements for the ends of said span brackets secured to said stiles comprising bent strap metal formations having at their ends apertured securement ears and at intermediate portions thereof inwardly offset sections for disposing said span bracket pivots in vertical alignment to clear the inwardly converging portions of said foldable stiles.

3. In a stepladder, a pair of frontal stiles converging from a relatively narrow uppermost tread width to a correspondingly wider lowermost tread width, a pair of rear stiles having corresponding convergence, a plurality of platforms foldably positionable at different levels inter mediate said front and rear stiles, a pair of brace rails for supporting said platforms at different levels, pivots at the extremities of said rails, and pivot brackets comprising integral strap metal formations having inwardly disposed offset portions for supporting the pivotal extremities of said rails so that upon folding of said brace rails their intermediate sections will clear the inwardly converging stiles above the pivoted levels.

4. In a foldable platform-tread ladder, a pair of front stiles having a predetermined downwardly divergent spread, a pair of rear stiles having a corresponding spread, pivot means about which the rear stiles are movable toward and away from the front stiles, a series of pairs of parallel brace rails pivoted at the interior surfaces of said front and rear stiles, rectangular platform treads associated with corresponding rails of each pair, and inwardly offset pivotal support brackets secured to the inner surfaces of said stiles and having an offset dimenslon substantially equal to the horizontal component of spread angle of each stile for carrying the pivotal articulation of its related brace rail so that when said front and rear stiles are folded together and said brace rails become extended upwardly, the uppermost extremities of the latter members together with their associated rectangular platform treads will lie between the interior surfaces of the folded stiles without conflicting therewith on account of the reduced horizontal clearance therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 1,154,147 Warren Sept. 21, 1915 1,801,211 Schulzke Apr. 14, 1931 1,980,004 Schramm Nov. 6, 1934 2,108,295 Prucha Feb. 15, 1938 2,191,755 Dearing Feb. 27, 1940

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