US2864544A - Self-supporting folding ladder - Google Patents

Description

u M w m m w l 4% 41% F 1 M A W a B m y S Q l v WW FLQKNR I R H 4. m 7M 0 3.0m. A l I F W Y B Dec. 16, 1958 w. SCHEIDEGGER SELF-SUPPORTING FOLDING LADDER Filed Nov. 18, 1957 I plates.

2,844,544 Patented Dec. 16, 1958 2,864,544 a a i SELF-SUPPORTING FOLDING LADDER Walter Scheidegger, Montague, N, J.

Application November 18, 1957, Serial 0. 697,090

2 Claims. (01. 228-47 i The present invention relatesto ladders and more particularly to combination ladders which may be used as a self supporting ladder-or an extension ladder which rests against a building or the like for support.

Heretofore ladders have been known that are self supporting as well as extensible, but such ladders have required complicated construction which has been expensive to manufacture and has required special tools for manufacture. The repair and maintenance of such previously known ladders has been a problem and therefore such ladders have frequently become unsafe, resulting in injury to the users thereof.

An object of the present invention is to provide a combination ladder which overcomes the disadvantages of prior structures and which can be inexpensively manufactured without requiring specialized equipment.

Another object is to provide a ladder which is useful in open spaces such as orchards or the like without requiring a structure against which the ladder must be supported, and which can readily be converted to an extension ladder where greater heights are encountered and where the ladder can be supported by leaning against an existing structure.

A further object is to provide a connecting joint for ladder sections which will positively connect ladder sections and prevent the bases of the ladder sections from separating even though the surface supporting the ladder is smooth.

Other and further objects will be apparent as the description proceeds and upon reference to the accompanying drawing in which:

Fig. 1 is a perspective view of the combination ladder with the sections connected as used for a step ladder in which both sections may be climbed at the same time.

Fig. 2 is an elevation of the combination ladder set up as an extension ladder and leaning against a vertical wall.

Fig. 3 is a fragmentary side elevation of the upper ends of the ladder sections showing the connection structure which provides for use as either a self supporting ladder or an extension ladder.

Fig. 4 is a fragmentary section taken on line 4-4 of Fig. 3 showing one means of connecting the plates to the lower ladder section.

Fig. 5 is a fragmentary section similar to Fig. 4 showing another means for securing the plates in position.

Briefly, the combination ladder of the present invention includes a first section having side rails and rungs and a narrower second section adapted to have its rails received between the rails of the first section. At the upper end of the first section metal plates positioned on the inner faces of the rails project from one edge of such rails and carry a rod connecting the projecting portions of the The rod is located outwardly from the rails a sufficient distance so that the rails of the second section may slide between the rod and the rungs of the first fsection to'permit extension of the second section beyond the first section. The projecting portion of the plates are provided with L-shaped slots extending from the top edge of the plates and toward the rails of the first section. A rod extends through the top ends of the rails of the second section U and projects therethrough being adapted to engage with said L-shaped slots and also to engage grooves in the rails of the first section, the parts interengaging to positively limit angular opening of said first and second sections to a predetermined safe value, the parts being designed and made to support a workman in safety. The second section is provided with hooks forming detents for engaging with the rings of the first section which provide for maintaining the ladder sections in adjusted position when the ladder is used as an extension ladder. The rod connecting said plates in cooperation with the hooks serving to maintain the ladder sections when extended in safe assembled condition.

Upon more detailed reference to the drawing a first ladder section 10 has spaced rails 11, 11' with rungs 12 extending therebetween and supported thereby. A second section 13 of substantially the same length has rails 14, 14' spaced closer together than the rails 11, 11 of said first section with rungs 15 extending between said rails of said section and supported thereby whereby said second section may be received between the rails of said first section.

Metal plates 16, 16 mounted on the inner faces of rails 11, 11 are secured by means of a plurality of bolts 17 passing therethrough and having nuts 18 for maintaining them infixed position. An alternate manner of securing the plates in position is shown in Fig. 5 Where bolts 19 extend through rail 11 and plate 16 being threaded into plate 16 providing smooth inner and exterior surfaces. It will be evident that rivets may be used in lieu of bolts.

Each plate is provided with an L-shaped slot having a stem portion 20 and foot portion 21 extending from the top edge of the plate 16 and 16' toward the rails 11, 11' of the first section 10. A rod 22 is mounted on the projecting upper and outer end portion of the projecting plates and is adapted to engage the one edge of the rails 14, 14' of the second section away from the first section, the rod being secured by any suitable positive means such as by riveting the ends, welding or the like, suitable grooves 23 being provided on the said one edge of the rails of the second section 13 for positive engage ment with the rod 22.

A rod 24 extends through the rails 14, 14' of the second section with its ends projecting outwardly and adapted for positioning in the L-shaped slots for positive connection of the two sections when assembled in an inverted V arrangement for use as a step ladder without external support. The rails 11, 11 may have grooves 25 registering with foot portions 21 of the L-shaped slots for receiving the ends of the rod 24.

It will be observed that the connection formed by plates 16, 16 with the L-shaped slots and rods 22 and 24 with grooves 23 and 25 positively maintain the ladder in a definite angular relation so that the ladder as shown in Figure 1 may be used on a smooth surface with no danger of the bases of the ladder sections spreading beyond the position shown.

The ladder section 13 is provided with detent hook means 26, 26 adjacent the bottom rung which may engage with any rung 12 of the ladder section 10 and rod 22 is adapted to engage the one edge of the rails of the second section whereby the total length of the ladder may be adjusted as shown in Fig. 2, the rod 22 being spaced from the rails a sufiicient amount to permit sliding of the second ladder section 13 relative to the first ladder section 10. It will be apparent that other types of detent means may be used such as pivoted lever detents in lieu 3 of fixed hooks 26 so that the ladder may be extended or retracted without requiring outward movement of the bottom of the second section 13.

The present invention provides a combination ladder having numerous uses wherein both sections may be used to support persons or the ladder may be used as an extension ladder.

It will be apparent that various changes may be made within the spirit of the invention and within the scope of claims.

What is claimed is:

1. A ladder for alternate use as an extension ladder or a step ladder comprising a first section having spaced side rails with rungs extending between the side rails and supported thereby, a second section of substantially the same length as said first section and having its rails spaced closer together than the rails of said first section with rungs extending between said rails of said second ection and supported thereby, whereby said rails of said second section may be received between said rails of said first section, a plate mounted on the inner face of each rail of said first section at one extremity thereof, each plate having a portion projecting outwardly from one edge of its rail, each plate being provided with an L-shaped slot with the stem extending from the edge of the plate adjacent the one end of the first section and the foot extending toward the associated rail, a rod mounted on the outer projecting portion of said plates spaced from said L-shaped slots and adapted to engage one edge of the rails of said second section away from such first section, a second rod extending through the rails of said second section, said second rod being continuous from one end to the other thereof and the ends of said second rod projecting outwardly beyond the outer surface of the rails of said second section a distance appreciably greater than the difierence in width between the outside surfaces of the rails of said second section and between the inside surfaces of the rails of said first section, and to substantially overlap the rails of said first section, said outwardly projecting ends of said second rod being adapted for positioning in said L-shaped slots for positive connection of said one ends of said first and second sections.

2. The invention according to claim 1 in which the said edges of the rails of said second section away from said first section are provided with notches to receive said first rod to additionally positively maintain said ladderzsections inan inverted V-shape relation whereby both ladder sections maybe climbed.

References Cited in the file of this patent UNITED STATES PATENTS 1,351,146 Zerlini Aug. 31, 1920 FOREIGN PATENTS 447,498 Italy Apr. l2, 1949

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