US2234944A - Collapsible ladder - Google Patents

Description

March 11, 1941. H. B. RICH ET AL 7 2,234,944

GOLLAPSIBLE LADDER Filed July 5, 1959 2 Sheets-Sheet 1 jfiwnflafl K10 lberi firflmef l INVENTORS March 11, 1941. H. B. RICH ET AL COLLAPSIBLE LADDER 2 Sheets-Sheet 2 36 H ly" Filed July 5, 1939 award f /barf $41976 lNVE TORS Any N Patented Mar. 11, 1941 COLLAPSIBLE LADDER Howard B. Rich and Albert Kramer, Cincinnati, Ohio Application July 3, 1939, Serial No. 282,731

2 Claims.

The present invention relates to a collapsible ladder, and especially toone of the platform type.

An object of the invention is to provide a collapsible platform type of ladder characterized by a high degree of stability and safety when in use.

Another object of the invention is to provide a ladder of the character stated, having a minimum number of movable parts, whereby the extending and collapsing action is greatly simplified, while at the same time manufacturing and selling costs may be materially reduced.

A further object of the invention is to provide in a collapsible platform type of ladder, a simple and durable means for preventing accidental collapse of the structure, said means being designed particularly for simplicity, rigidity and dependability. V

Another object is to provide a platform type of ladder, with an improved platform structure made in such manner as to incorporate, at a negligible cost, a compartment for the storage of tools, implements, and supplies.

The foregoing and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. lis a perspective view of the improved platform type of collapsible ladder embodying the invention.

Fig. 2 is a rear view of the device of Fig. 1, showing the structure in the collapsed condition.

Fig. 3 is a side elevational View of the ladder, showing the relationship of the parts when the ladder is collapsed or folded for storage.

Fig. 4 is a perspective view of a bucket holder which forms a detail of the invention.

The platform type of collapsible ladder is not a broadly novel piece of equipment, and no claim accordingly is made thereto in the broad sense. However, the present invention recognizes the existence of various faults and insufiiciencies in the known structures, and presents a solution thereto, especially as concerns the foldabilit'y characteristic of the platform and its means of suspension relative to the foldable legs of the structure. With this objective in view, reference is had to the accompanying drawings showing the various improvements set forth in the appended claims.

The ladder structure comprises generally a head piece 5 having opposite ends to which are secured the leg supporting brackets or depending aprons 6. At the forward-ends of the brackets or depending aprons; the front legs I and B may be fixed, by means of rivets or other fastening devices 9, with the legs disposed forwardly at an angleto the mean plane of the head piece. The legs preferably are slightly divergent, and

'at intervals along their length, a suitable number of steps if! may be supported between them. 5

At the rear ends of the brackets 63, pivots I2 10 may be provided for pivotally mounting upon the bracket the rear leg structure which comprises the pair of spaced legs l3 and M, which may also be slightly divergent from the region of the head piece toward the feet of the legs. rear legs may be suitably braced in the interest of strength and stability, there being illustrated for the purpose, a pair of cross braces or bars l5. An additional brace It, which may be in the form of a rung or connecting shaft It, may be furnished if necessary or desirable. The pivots I2 enable movement ofthe rear legs from the operative or extended position of Fig. 1, to the inoperative or collapsed position of Figs. 2 and will be disposed in substantial parallelism.

Attention is now directed to the platform I! and the supporting means therefor about to be described. The platform may be constructed of any suitabale material capable of furnishing a slab or panel, and by preference the opposite edges 18 and [9 thereof are reinforced With ver-- The .1

s, so that in the latter position, all of the legs 25 at its opposite ends to the legs I and 8 as indi- 40 catedat 22. Referring to Fig. 2, it will be noted that the side pieces 20 of the platform are drilled or otherwise apertured at 23 for reception of the pivot rung 2|, so that the platform may be swung from the position of Fig. l to the position of Fig. 2, at which latter position the platform is disposed between the legs 1 and 8 with its mean plane in substantial parallelismtherewith. The platform preferably tapers in Width, from front to rear so as to coincide with the space existing between the slightly divergent legs 1 and 8.

At a location near the pivotal mounting 2|, the ends of the side pieces have applied thereto a transverse board or strip 24 for closing the space between said side pieces 2i), while'a transverse 55 panel 25 extending from said closed ends and rearwardly toward the opposite ends of the side pieces, furnishes a compartment or chamber for tools, implements, supplies and the like such as are ordinarily used concurrently in the use of the ladder. The open mouth 26 of the compartment or chamber is directed toward the rear legs of the ladder structure, whereas the closed end 24 of the compartment is disposed adjacent to the forward edge 21 of the platform. From the foregoing it should readily be understood that in the upright position of the platform, the mouth 26 of the compartment will be uppermost, thereby to provide a quite suitable storage space for the articles previously mentioned. The mouth of the compartment is freely accessible when the ladder is collapsed and standing on end as illustrated in Fig. 2.

The rear or right hand end of the platform is adapted to be supported primarily upon a stop 28, which may be in the form of a rung or spacer shaft that spans the rear legs l3 and I4. A secondary means of support for the rear end of the platform, is a pair of platform lock and suspension links indicated by the character 29. It should be noted particularly that the links 29 actually suspend the platform, and would assume the full responsibility for supporting the rear end of the platform in the event of breakage or removal of the stop means 28. A double safety feature is thereby incorporated into the structure at that end of the platform, which is not pivotally mounted. The upper end of each link is pivoted to a rear leg at 30, While the lower end thereof is pivoted to the side of the platform at 3|. The pivot 30 is at a higher elevation than the pivot 3|, in the extended or operative condition of the ladder structure. In addition to the suspending function of the links, there is evident also the fact that the links cooperate with the sides of the platform to form a toggle structure, which must pass a dead center relationship of the pivots 2|, 3| and 30 in order to dispose the platform to the operative horizontal position of Fig. 1. It is accordingly impossible for the structure to collapse accidentally, since to effect the collapsing or folding action, it is necessary to first elevate the rear end of the platform beyond the position at which the pivots 2|, 3| and 30 are in alignment. Once the platform end is elevated beyond the dead center position, the rear legs may be moved toward the front legs, and the links 29 will serve to automatically guide the platform to the upright position of Figs. 2 and 3. The length of link required for thusly guiding the platform will be dependent upon the elevation of pivots 3|] upon the rear legs, and the location of pivots 3| with respect to their distance from the forward pivots 2| of the platform. It will accordingly be appreciated that the linkage means above described will preclude accidental collapse of the leg structors, while at the same time forming a means of guiding the platform toward and from the operative position. The links, by reason of the particular arrangement or relationship to the legs and platform sides as herein disclosed, may be made short and rigid for the purpose of enhancing the strength and stability of the ladder as a whole.

Referring to the illustration of Fig. 1, it will at once be evident that a weight imposed upon the platform will be supported primarily by the stop means 28, and secondarily by the suspension links 29. Moreover, should a person using the ladder stand upon the forward edge of the platform to the left of pivot 2|, the inclined links 23 will effectively preclude rotation of the platform about pivot means 2| in the counter-clockwise direction, due to inability of the rear legs to shift under the applied weight. It should be noted particularly that none of the parts of the platform supporting structure normally will be required to oppose a compressive force, and for this reason the parts may be made of light material without sacrificing strength and rigidity. The platform and the head piece of the ladder may be furnished with any suitable type of means for supporting a bucket or other container that might frequently be used in connection with the ladder. For this purpose, a bucket holder 32 may be furnished, in the form of a resilient wire loop having opposite ends bent downwardly and outwardly as at 33 and 34, respectively. The bent portions 33 and 34 preferably are disposed in a plane which is substantially at right angles to the plane of the loop. A pair of elongated apertures 35 and 36 may be provided in the head piece, for reception of the sections 33 and 34 of the bucket holder, which sections may be inserted into the apertures by slightly contracting the loop, and after insertion of the sections, permitting the loop to again expand for disposing the outwardly turned ends 34 against the adjacent solid portion of the head piece. Similar elongated openings may be provided in the rear portion of the platform, as indicated at 31, to accommodate the bucket holder 32. It is considered desirable and advantageous to cut away a portion of the material between the elongated apertures, at the locations 38 and 39, to fit the curvature of a bucket or container held within the loop. As indicated in Fig. 2, the elongated perforations 31 extend through the platform and may therefore be used for holding the loop in storage against the bottom or under face 40 of the platform when not in use. The forward portion of the head piece may be cut away at 4| if desired, in order to enable the user of the ladder to utilize a substantial area of the platform when standing thereon.

It is believed that the advantage of extreme simplification and elimination of parts is readily evident from the disclosure of the invention herein rendered, and that the advantages specified in the objects at the introduction to the specification will be found inherent in the structure disclosed.

It is to be understood that various modifications and changes in the structural details of the de vice may be made, within the scope of the ap pended claims, without departing from the spirit of the invention.

What is claimed is:

1. In a collapsible ladder of the platform type, the combination of a head piece and a pair of spaced straight front legs secured thereto at an inclination to the plane of the head piece, steps supported upon said front legs, pivot means on the legs at an elevation above the steps, a platform having a forward end attached to said pivot means whereby said platform may be swung from a position in substantial parallelism with the front legs, to a horizontal position transversely thereof, a pair of rear legs pivoted to the head piece and movable in unison toward and into substantial coplanar parallelism with the front legs, at each side of the ladder, in the collapsed condition of the ladder, an abutment adjacent to each rear leg located at an elevation thereon to limit the pivotal movement of the platform to the operative horizontal position, a pair of short auxiliary suspension links for suspending a portion of the weight of the platform each having an end pivoted to a rear leg, and an opposite end pivoted to the platform, the first mentioned pivot end of each link being, in the fully extended condition of the ladder, disposed at such a higher elevation than the pivot end at the platform that the included angle formed between the link and the plane of the platform, is greater than the included angle formed between the link and the rear leg, whereby each link is caused to perform as an auxiliary support for the platform additional to the abutment aforesaid, and to provide a toggle action of the link movable past a dead center aligned relationship of the link with the mean plane of the platform, precluding accidental collapse of the ladder.

2. In a collapsible ladder of the platform type, the combination of a head piece, a pair of de-- pending aprons thereon, and a pair of spaced front legs having straight inclined upper portions secured one to each apron at an inclination to the plane of the head piece, in the extended condition of the ladder, steps supported upon said front legs, pivot means on the legs at an elevation above the steps, a platform having a forward end attached to said pivot means and between the legs whereby said platform may be swung from a position in substantial parallelism with and between the front legs, to a horizontal position transversely thereof, a pair of rear legs pivoted one to each apron, in the planes of the front legs, and movable in unison toward and into substantial coplanar parallelism with the front legs in the collapsed condition of the ladder, an abutment adjacent to each rear leg located at an elevation thereon to limit the pivotal movement of the platform to the operative horizontal position, a pair of short platform suspension links each having an end pivoted to a rear leg, and an opposite end pivoted to the platform, the first mentioned pivot end of each link being, in the fully extended condition of the ladder, disposed at such a higher elevation than the pivot end at the platform that each link, in. the extended condition of the ladder, makes a greater acute angle with the plane of the platformv than it makes with its associated rear leg, thereby to assume part of the platform weight and to provide a toggle action of the link movable past a dead center aligned relationship of the link with the mean plane of the platform, precluding accidental collapse of the ladder,the length of each link being such as to guide the pivoted platform to a position of complete repose between the front legs, in substantial parallelism with the front legs when the ladder is fully collapsed.

I HOWARD B. RICH. ALBERT KRAMER.

, I CERTIFICATE OF CORRECTION, v Patent No. 2351591114.. v v I March 11, l9lil.

HOWARD B. RICH and ALBERT KRAMER.

It is hereby certified that the. above numbered patent was erroneously issued to the inventors, said "HOWARD B. RICH and ALBERT KRAMER" whereas said patent should have been issued to The Rich Ladder and Manufacturing Company, of Cincinnati, Ohio, a corporation of Ohio, as assignee of the entire interest therein, as shownby the record of assignments in this office; page 2, first column, line 62, for "structorsfl read -s tructures--; andthat the said Letters Patent should be read with this correction therein that "the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of April, A. D d; 1911.1.

Henry Van Arsdale, 7 (Seal) Acting Commissioner of Patents.

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