US2183251A - Metallic ladder - Google Patents

Description

R. PIBEGGS 2,183,251 METALLIC LADDER Dec. 12, 1939;

Filed Jan. 23, .1939

Patented Dec. 12, 1939 UNITED STATBS METALLIG LADDER Ray P. Beggs, Oklahoma City,'0kla., assignor to George W. Hassell, Oklahoma City, Okla.

Application January 23, 1939, Serial No. 252,460

3 Claims.

This invention relates to foldable metallic ladders. The development of the airplane has brought upon the market, and made available for use, tubing which, while being very light, is also exceedingly strong. It is the primary object of the present invention to use this tubular material in connection with the construction of foldable metallic ladders, and to employ in conjunction therewith a novel means for rendering the hinged joints between the ladder sections very strong and rigid when the ladder is extended for use.

In the accompanying drawing:

Figure 1 is a fragmentary side elevation of a portion of the ladder showing the manner in which a number of sections may be hinged together in such fashion that they may be folded into very small compass when not in use;

Fig. 2 is a front elevation of a portion of the ladder showing one of the joints hereinafter described;

Fig. 3 is a fragmentary vertical section upon line 3-3 of Fig. 2;

Fig. 4 is a detail view of a brace plug, hereinafter described, and

Fig. 5 is a horizontal sectional view upon line 55 of Fig. 3.

Like numerals designate corresponding parts throughout the several figures of the drawing.

In the drawing, A, B and C represent ladder sections hingedly connected to each other, as indicated at 5, to adapt them to be folded in the directions indicated by the arrows. The several sections consist of side rails 6 and cross rungs l. The sections 6 consist of tubes, and the rungs 1 may consist of rods or tubes, welded into place between the rails 6 to constitute steps in the manner common in ladders.

The elements 6 and 1 may be made of any of the well known, light, and exceedingly strong alloys which have recently found such wide favor in those places where great strength coupled with light weight is essential. Duralumin, for example, is a material which I may employ in the manufacture of these ladders.

Plugs 8, which may be either solid or of tubular formation, are slidably disposed within the tubular rails and in a position to span the joints between the meeting ends of the rails. These plugs are made to fit so snugly that while they may be easily slid into overlapping relation with respect to the joints, they prevent any wobbling at the joints.

A slidable rung l associated with each of the meeting ends of a pair of sections, serves the double function of a rung and of an actuating means for the associated plugs 8. This slidable rung has its end engaged in the transverse slots 8 of the respective plugs, and said slidable rung travels in slots 9, of inverted J-shape, formed in the inner faces of the rails 6 of the section B, for example.

When it is desired to collapse the ladder, the slidable rung is moved downwardly in the slot 9 until said rung lies adjacent the next lower fixed rung, indicated at l in Fig. 3. This lowering of the slidable rung lowers the plugs 8 until said plugs no longer overlap the joint, or, in other words, no longer project upinto the next uppermost ladder section A. The ladder sections may then be folded together as described.

When it is desired to extend the ladder sections for use, they are swung into alignment with each other, and the slidable rungs are moved upwardly in slots 9 to bring the plugs 8 to the position illustrated in Fig. 3, at which time said plugs overlap the joint and lie partly in the section A and partly in the section B. This rigidly aligns the ladder sections and prevents any wobbling at the joint.

To hold the plugs in the elevated position described, the slidable rung is slipped laterally in the slots 8 of the plugs to lie in the downwardly curved portion 9 of said slots. Thus, it requires a-positive upward and then a lateral movement of the rung to bring said rung into position to descend and move the plugs to ladder section releasing position. Consequently, there is no possibility of an accidental disengagement of the plugs, with possible consequent injury to the person using the ladder.

While the construction shown and described is an exceedingly simple, strong and economical one, it will be apparent that other ways may be resorted to for accomplishing the same general result. Consequently, it is to be understood that the invention is not limited to the particular means shown and described for actuating theplugs or for supporting them in elevated position. Upon the contrary, the invention includes within its purview any equivalent way of accomplishing this result falling within either the terms or the spirit of the appended claims.

Having described my invention, what I claim is:

1. In combination, hinged ladder sections comprising tubular, metallic rails and metallic rungs, means for hingedly connecting the abutting rails of adjacent ladder sections, members slidably mounted within the tubular rails and movable to and from overlapping position with respect to the joint between the said rails, and means for holding said members in such overlapping position, said last-named means comprising a slidable rung engaged with said members and means for supporting said rung in position to hold said members in joint-overlapping position as described.

2. The combination with a pair of tubular ladder sections, each comprising a pair of tubular side rails and integral metallic rails, the rails of one ladder section being provided with slots upon its inner face, of a pair of plugs slidably mounted in the side rails of one ladder section and adapted to be projected into overlapping engagement with the side rails of the next adjacent section, and means movable in said slots for actuating said plugs, the means movable in the slots comprising a transverse bar constituting a slidable rung.

3. The combination with a pair of ladder sections, each comprising a pair of tubular metallic side rails and a plurality of transverse, integral rungs, of means for hingedly connecting the meeting ends of the side rails of one ladder section with the ends of the side rails of an adjacent ladder section, the side rails of one section being provided upon their inner faces adjacent their hinged ends with vertical slots, said slots being curved over at their upper ends to form offset recesses, plugs slidably mounted in the side rails for movement to overlapping position with respect to the joint between the rails of the adjacent sections, a slidable rung vertically movable in said slots, and means for connecting the ends of said rung to the plugs in such manner as to permit lateral movement of the rung with respect to the plugs, such lateral movement permitting the lateral shifting of the rung with respect to the plugs to cause said rung to lie in the off-set recesses of the slots and to thereby hold the plugs in elevated position and in overlapping relation to the joints between the ladder sections, as and for the purposes described.

RAY P. BEGGS.

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