Ladder Scaffold

Abstract

A scaffold is provided which employs as its platform portion a conventional straight-type ladder. The invention includes a pair of end leg assemblies each having a channel-shaped upper head portion for receiving end portions of the ladder therein and for connecting the leg assemblies to the ladder. The leg assemblies have a reinforcing crosspiece from which a strut angularly extends. Such struts have clamps at their free end for releasably engaging rungs of the ladder for holding the leg assemblies in fixed position relative to the ladder.

Description

BACKGROUND OF THE INVENTION

There is a great need for small portable scaffolds such as the type which are necessary in painting homes, repairing siding, and other similar uses. Various contraptions have heretofore been employed such as adjustable sawhorses, as shown in U.S. Pat. No. 970,508, and other complex structures some of which use ladder sections, as in U.S. Pat. No. 372,133, but in no one of the patents mentioned is there an extremely simplified arrangement which uses a straight-type ladder as the platform structure.

SUMMARY OF THE INVENTION

Accordingly, it is an important objective of the present invention to provide novel end support assemblies capable of ready attachment to the ends of a conventional straight-type ladder whereby the ladder can serve as the platform portion of the scaffold.

A more particular object of the present invention is to provide a ladder scaffold of the type described wherein the end support assemblies have a novel structure comprising a pair of legs integrated at their upper ends with a U-shaped head and also including a reinforcing crosspiece extending between the legs to which is connected one end of a strut the other end of which is adapted for releasable connection to a rung of the ladder for providing a rigid connection between the ladder and the leg assemblies.

The invention will be better understood and additional objects and advantages will become apparent from the following description which illustrates a preferred form of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the ladder scaffold of the instant invention;

FIG. 2 is an enlarged, fragmentary cross-sectional view taken on the line 2--2 of FIG. 1; and

FIG. 3 is an enlarged fragmentary sectional view taken on the line 3--3 of FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring in particular to the drawings, the numeral 10 designates a conventional straight-type ladder having a pair of side rails 12 and rungs 14. The ladder shown comprises a conventional steel or aluminum ladder wherein the side rails are generally channel-shaped or the like and the rungs are hollow and open through the outer sides of the rails. The present invention is adaptable to wooden ladders also even though rungs of wooden ladders are not hollow, as will be described in greater detail hereinafter.

For the formation of a scaffold structure of the invention, there is provided a pair of end support assemblies 16 of identical structure, each having a pair of divergent legs 18 integrated at their upper ends with a crosshead 20. Head 20 is channel-shaped, having a substantially rigid body portion 22 and end upright tabs or walls 24 spaced apart a distance at least as wide as the width of a ladder so that the latter is adapted to lie in the head as illustrated in FIGS. 1 and 2. Legs 18 may comprise telescoping sections 18a and 18b, with the section 18b having apertures 25 and the section 18a having a cross pin 26 engageable with a selected one of said apertures for adjusting the length of the legs and therefore the height of the scaffold.

The ladder is secured to the heads 20 by bolts 27 which extend through suitable apertures 28 in the upper portion of the walls 24 and which are adapted to receive end nuts 30. As stated hereinbefore, the rungs 14 of conventional steel ladders are hollow and open through the outer sides of the ladder rails 12. In such case, the bolts 27 can extend through the rungs and no alteration of the ladder is necessary. If wooden ladders or other ladders which may not have the open-ended rungs are used, it is necessary to drill cross holes in the side rails of the ladder offset from the rungs to receive the bolts 27.

Each of the end support assemblies has a cross brace 32 secured to the legs 18 in parallel relation to the head 20 and spaced down therefrom. Rotatably supported on the cross brace 32 is a mounting sleeve 34 from which integrally extends a strut member 36 adapted to be connected at its free end to a rung of the ladder inward from the end rung for holding the leg assembly in a fixed downwardly angled position with relation to the ladder. For the purpose of connection to a rung of a ladder, the strut member 36 has a clamp 38 on its free end. As shown in FIG. 3 such clamp may comprise a pair of fingers 40 secured to the end of the strut member 46 by a bolt 42 and having end recesses 48 formed therein for gripping a rung.

Thus, to form a scaffold of the invention, the two-end support assemblies 16 are secured to opposite ends of the ladder, or at least in spaced relation of the latter, by inserting the connecting bolts 27 through the upturned walls 24 of the heads 20 and through the ladder. In the case of metal ladders the bolts 27 usually can extend through the rungs and in the case of wooden ladders holes have to be drilled in the side rails in a position offset longitudinally of the rungs. After the end support assemblies are connected to the ladder by the bolts 27, the struts 36 are secured to a selected rung of the ladder to rigidly hold the support assemblies in a fixed downwardly extending supporting position. Struts 36 may be adjustable in length as by telescoping sections 36a and 36b, connected by a plurality of apertures 50 in the section 36b and a pin 52 in the section 36a in order that the struts may be lengthened or shortened as desired to position the leg assemblies at the desired angular relation to the ladder.

According to the present invention a conventional ladder is adapted readily to be converted into a scaffold by merely installing the leg assemblies 16 thereon. Such ladders are usually light in weight and thus are very useful as an element of the present combination in order that the scaffold can be readily moved from place to place. A narrow strip of plywood or any type of board, not shown, may be laid on the ladder to form a supporting surface on which the worker can stand.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention.

Claims

Having thus described my invention, I claim:

1. A scaffold construction arranged to employ a straight-type ladder having side rails and a plurality of rungs, comprising

a. a pair of leg assemblies one for each end of a ladder,

b. each of said leg assemblies having a pair of legs integrated at its upper ends to a crosshead on which one end of the straight-type ladder is arranged to be supported and form the platform portion of the scaffold,

c. said crossheads having upturned walls adjacent each of their ends to form U-shaped housings to receive the ladder,

d. fastening means extending through said upturned walls arranged to project through the rails of said ladder for releasably securing said crossheads to the ladder,

e. a cross brace in each leg assembly secured between each of said respective pairs of legs in a position below said crossheads,

f. and a strut member in each of said leg assemblies having opposite ends,

g. one of the ends of said strut members being secured to a respective cross brace and the other end of said strut members being arranged to be secured to an intermediate portion of the ladder to form an angled reinforcing member.

2. The scaffold construction of claim 1 wherein said fastening means comprises a bolt.

3. The scaffold construction of claim 1 including releasable clamp means on said other ends of said strut members for releasably securing said strut members to intermediate rungs of the ladder.