US3005513A - Stepladders and structural components thereof - Google Patents

Description

Oct. 24, 1961 c. E. LARSON 3,005,513 STEPLADDERS AND STRUCTURAL COMPONENTS THEREOF Filed March 25. 1959 2 Sheets-Sheet 1 INVENTOR. CLAYTON E LARSON M e/41m,

A TTORNE Y Oct. 24, 1961 c. E. LARSON 3,005,513

STEPLADDERS AND STRUCTURAL COMPONENTS THEREOF Filed March 25. 1959 2 Sheets-Sheet 2 INVENTOR. CLAYTON LARSON MM/QM,

ATTORNEY United States Patent 3,005,513 STEPLADDERS AND STRUtITURAL COIVHO- NENTS THEREQF Clayton E. Larson, Weston, COHXL, as'signor to White Metal Rolling 8; Stamping Corporation, Brooklyn,

N.Y., a corporation of New York Filed Mar. 25, 1959, Ser. No. 801,751 2 Claims. (Cl. 182-165) This invention relates to stepladders and structural components of ladders and is more particularly concerned with stepladders possessing the characteristics of structural and mechanical simplicity, light-weight, economy of manufacture and compactness for storage.

Field of invention There exists a real consumer demand for a stepladder providing structural simplicity, stability, minimal weight and compactness for storage and which does not include spreaders because of the attendant hazard of malfunction of spreader elements or collapse of a spreader retained ladder structure. Use of spreaders in ladders are also a problem because they contribute to increased bulk, multiplicity of manufactured units and difficulty in converting the ladder from a folded to an open position. Further, ladder spreaders present various problems of design and economy in the manufacture of stepladders.

A solution to this situation is provided by the present invention which offers a stepladder without the necessity for spreader means.

Another problem attendant upon the manufacture and use of ladders in general, lies in achieving an attachment between the steps and side rails of ladders which will resist both torsional and direct forces. This problem is pronounced in the fabrication of ladders from extruded light metals wherein the side rails and steps are commonly formed from light weight channel members. A remedy for this situation is offered by the present invention in which at novel tread and uniting arrangement provides a stronger connection and more stable structure.

Still another difficulty encountered in the fabrication of stepladders is that of uniting the front and rear sections by means which will allow pivotal movement between these sections while enduring considerable amounts of strain and wear. A novel lug member provided by the present invention provides a solution for this problem.

Objects A principal object of this invention is to provide new improvements in ladders. Further objects include: the decrease of material requirements for manufacture; provision for a ladder of structural simplicity; increased ease of manufacture as the result of the curtailment of the number of necessary structural units and assembly opera,- tions required; economic benefits resulting from the diminishing of assembly and material requirements; elimination of the possibility of mechanical malfunction present in stepladders utilizing spreader means; enhancement of stepladder storage characteristics; elimination of the difliculties presented by the setting up and folding of stepladders equipped with spreaders; provision of a strong and stable union between the steps and side rails of ladders in general and between the front and rear sections of stepladders, and enhancement of the tractive and cushioning support of ladders.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereafter. 'It should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

General description These objects are accomplished according to the pres-,

ent invention by forming a stepladder comprising a front section, a rear propping section and uniting means which serves to pivotally attach the front and rear sectionsqin.

provides a stepladder structure which may assume a com-.

pact or folded position in which the side rails of the two sections are parallel, or the sections may be spread apart to form an acute angle. When the sections are spread in order to place the ladder in a} stable, independent posi tion for use, the upper ends of the rear section side rails, which are angular, abut upon the rear edges of the upper ends of the front section side rails, thereby acting as a stop means to limit the rotation of the front and rear sections about the point of pivotal attachment andeliminating the necessity for manipulation or adjustment of spreader means.

The uniting member by which the front and rear sections are connected is fashioned in the form of a lug with a projecting lateral flange which may be attached to the rear edge of the front section side rails. The upper ends of the rear section side rails are pivotally attached to the lug member which extends rearwardly of the front sec-.

tion side rails and the forward portion of the lug plate is fixed to the lateral surface of the front section side rail.- I Brace means are provided for the front and rear sec! tions. In the preferred form the front section is braced by means of elongate elements connecting the front edge.

of the front section side rails with the front, edge of the steps and the rear section is also reinforced by means Detailed description A more complete understanding of the'new devices of this invention may be had by reference to the accompanying drawings in which:

. FIGURE 1 is a perspective view of a preferred form of stepladder which is set up on position for use;

FIGURE 2 is a side View of the same ladder in a folded position; v

FIGURE 3 is a fragmentary, enlarged perspective view of an end portion of a step of the ladder;

, FIGURE 4 is an enlarged sectionalview of thelug 7 member and side rails taken along line URE 2;

FIGURE 5 is an enlarged, view of the step. and side'rail;

of FIG- fragmentary perspective FIGURE 6 is an end view ofa lug member of theladder; y v FIGURE 7 is a fragmentary side view ofthe foot member and side rail, and i FIGURE 8 is a fragmentary, sectional, end view of,

the bottom of a side rail and the attached foot member; Referring in detail. to the 'drawings, th eistepladder basically comprises afront section 2. which includes two Patented Oct. 24, 1961 In thisside rails 4 with a plurality of space apartsteps 6 and a top tread orplatform 8 fixed between theside rails 4. 7 Attached to the upper ends of thefront side rails 4 arelugmembers 10, described in more detail hereinafter, which are in turn pivotally attached at 1.2 to theside rails 14 of the rear propping section. The rearsection side rails 14 are provided with angular upper ends 16 which abut upon the rear edge of the upper ends of the front section side rails when the ladder structure is in aspread or open position as illustrated in FIGURE 1.

- The rearsection side rails 14 are also provided with two "or more bracernembers 1-8 which serve to hold theside rails 14 in a spaced-apart relation. In a preferred form wherein theside rails 14 are channel members comprising a central web and two spaced-apart laterally projecting flanges, one of the brace members 18- is attached at one end to the front flange of the left rearsection side rail 14 near the top thereof and at the other end to the from flange of the right rearsection side rail 14 near the bottom thereof. Thesecond brace member 18 is attached at one end to the front flange of the night rearsection side rail 14 near the top thereof and at the other end to the front flange of the left rear section side rail near thebot'tom thereof. The two brace elements are then attached, such as by rivets, to one another at their point of intersection. As shown in FIGURE 1, a second pair of brace members '19 may then be similarly attached to the rear flanges of the right and left rearsection side rails 14.

Additional brace elements may also be provided in order to enhance the stability of thefront section 2. Thebrace elements 20 may be attached at one end to the front edge of theside rail 4 at a point below the juncture of the side rail '4 and thebottom step 6, and at the other end to the front edge of thestep 6 equal to the distance from this juncture to the point of attachment of the other end of the brace element to theside rail 4.

'- The stepladder may be converted to a compact folded form for'storage in which the front and rear sections are parallel as shown in FIGURE '2, by rotating the rearsection side rails 14 about their point ofpivotal attachment 12,'toward the frontsection side rails 4.

"A preferred form of step for use in the invention and in ladders in general is illustrated by FIGURES 3 and 5. The step comprises a channel member including a central web 2.2mm spaced-apartlateral projections 24 which are formed integrally with theweb 6 and extend at an angle thereto. If desiredportions of theweb 22 may be made to project beyond theflanges 24 as shown at 26 in FIGURE 5, by setting in the point of juncture of theflanges 24 with thecentral web 6. The end portions of the web 22- are provided withrecesses 25 as shown in FIGURE 3, whereby the side rails, as shown by phantom lines in FIGURE 3, may be inserted in therecesses 25 and attached to thelateral flanges 24 of the step by rivets 3'2 which'extend throughholes 30.

To enhance the tractive qualities ofsteps 6, their upper surfaces are provided with serrations 38' at the front and 7 rear edges.

The lug member used for pivotally uniting the front and rear ladder sections is illustrated by FIGURES 4 and 6, and comprises a flat plate and a laterally projectingflange 44 formed integrally therewith. In a preferred form the lug member is provided with agroove 42 along the point of juncture of theflange 44 and theplate 10 on the side of the flange which engages thefront side rail 4. As shown in FIGURE 4, 'the'front side rail 4 is'attached to theplate 10 and the flange 44by means such as bolts or rivets. 34 and 36. The rear end of plate It) is attached torear side rail 14 bypivotal means 12.

To prevent marring and provide a tractive support surfgce for the ladder structure, foot elements illustrated by FIGURES 7 and 8 are provided. For descriptive purposes the foot element is depicted in conjunction withfront side rail 4. The foot elements comprise an L- shapedmember 46 which is attached to theside rail 4 byrivet 52 and to secure a stronger attachment agroove 54 is provided adjacent to the vertical projection of thefoot element 46 to receive the bottom of theside rail 4.

In the bottom surface of the horizontal projection ofmember 46, aresilient element 48 made of rubber or a similar substance, is inserted in therecess 56 and secured there by a rivet orsimilar means 50.

Having provided a complete description of the invention in such manner as to distinguish it from other inventions and from what is old, and having provided a description of the best mode contemplated of carrying out the invention, the scope of patent protection to be granted the invention is defined by the following claims.

I claim:

1. A stepladder comprising a front section including two side rails each comprising a central web, two spacedapart lateral projections formed integrally with said web which parallel the longitudinal axis of the Web and are normal to the web, means for connecting said two side rails in spaced-apart relation comprising a step including a central web, two spaced apart lateral projections formed integrally with said web which parallel the longitudinal axis of the web and project at an angle to the web, said central web being provided at each end with recesses spaced-apart a distance equal to the distance between said spaced-apart lateral projections of said side rails so that the lateral projections of the side rails may be inserted within the recesses provided in the central web of the step and attached to the lateral projections of the step, additional steps similarly fixed in a spaced-apart relation between said two side rails, a rear propping section comprising two side rails with angular upper ends, brace means for holding said rear section side rails in spaced-apart relation, means for pivotally attaching said rear section is said front section comprising a lug member carried near the top of one of the side rails of the front section and extending rearwardly of the rear edge of the side rail with one of the side rails of the rear section being pivotally connected thereto, a second lug member similarly attached to the other side rail of the front section and pivotally connected to the second side rail of the rear section, said lug members being spaced from the top of the front and rear section side rails so that the rear section side rails may be moved about the point of pivotal attachment to engage the angular upper ends of the rear section side rails with the rear edges of the front section side rails throughout a substantial extent of the angular surface and actingas the sole stop means for the rear propping section.

2. In a ladder having side rails comprising a central web and spaced-apart lateral projections formed integrally with the 'web, a step comprising a central web, two spaced-apart lateral projections formed integrally with said web which parallel the longitudinal axis of the web and project at an angle to the web, said central web being provided at each end with recesses spaced-apart a distance equal to the distance between said spaced-apart lateral projections of said side rail so that the lateral projections of the side rail may be inserted within the recesses provided in the end of the central web of the step and attached to the lateral projections of the step.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATION OFCORRECTION Patent N05 3,,OO5,,513 October 24 1961 Clayton E. Larson It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4line 36 for "is" read to Signed and sealed this 24th day of April 1962 (SEAL) Attest:

ESTON G. OHNSON DAVID La LADD Attesting Officer Commissioner of Patents

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