US1148350A - Ladder-scaffold. - Google Patents

Description

D. E. BROWN.

LADDER SCAFFOLD.

APPLICATION HLED JAN. 19, 1915.

' Patented July 27, 1915.

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DAVID E. BROWN, OF SYRACUSE, NEW YORK.

LADDER-SCAFFOLD.

Application filed January 19, 1915.

To all 10/2. out it may concern Be it known that I, DAVID E. BROWN, a citizen of the United States, and resident of Syracuse, in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Ladder-scaffolds, of which the following, taken in connection with the accompanying drawings, is'a full, clear, and exact description.

This invention relates to certain improvements in ladder scaffolds adapted to be used by painters and other craftsmen in work upon the interior or exterior of buildings where such work is required to be carried on at different elevations and over more or less extended areas.

I am aware that it is common practice to hook the tackle blocks of swingingscafiolds directly upon the rungs of ladders and that it :has been proposed to use certain more or less complicated forms of braces adjustably attached directly to the rails of the ladder for receiving and supporting the same tackle blocks. Usually two or more workmen are working upon the same scaffold at the same time and when the upper tackle blocks are attached directly to the rungs of the ladders, the combined load frequently results in the breaking of the rungs and consequent precipitation of the entire load of scaffold and workmen thereon to the ground with attendant loss of life or serious injury. Furthermore, in all of the scaffold-sopporting brackets with which I am familiar, the supporting member for the tackle blocks stands at a considerable distance from the ladder upon which the brackets are mounted so that the load of the scaffold with the workmen thereon produces excessive strains not only upon the bracket, but also upon the rails of the ladder, thus increasing the danger of accident through the breakage of either the bracket or ladder rails, or if the bracket is sufliciently heavy to withstand the load, it is too cumbersome for'convenience in handling or adjustment upon the ladder.

The main object, therefore, of my inven tion is to transmit the load of the scaffold with the workmen thereon directly upon and in close proximity to the rails of the ladder independently of the rungs for the purpose of increasing the safety of the scaffold and reducing'the liability of accident.

Another object is to make the ladder attachment iight, strong and durable so'that it may be conveniently handled and adjusted Specification of Letters Patent.

Patented July 27, 1915.

Serial No. 3,042.

along the rails of the ladder with the assurance that when once clamped in place it will support any load for which the scaflold is intended.

Another object is to provide simple and efficient means for adjusting the platform toward and from the building and for holding it in its adjusted position against swaying movement.

Other objects and uses will be brought out in the following description.

In the drawings Figure l is a perspective view of a portion of a ladder and adjacent end of the scaffolding mounted thereon. Figs. 2 and 3 are enlarged outer and inner face views of one of the rail clamps, shown as clamped to the adjacent portion of one of the ladder rails, the supporting rod for the scaffold being shown in cross section. Fig. 4 is a horizontal sectional view through the ladder and rail-clamping device taken in the plane of line 4-4:, Fig. 2. Fig. 5 is an enlarged side elevation partly in section of one of the adjustable brace-bars and supports for the platform. Fig. 6 is a longitudinal sectional view of the same brace-bar, taken on line 66, Fig. 5.

The scaffold forming the subjectanatter of my invention is adapted to be supported upon two or more ladders A- resting upon the ground or other support and leaning against the wall or portion of the building upon which the painting or other work is to be performed, the spacing of the ladders depending upon the length of the platform, as B, preferably one ladder at each end of said platform, and in view of the fact that the same device applies to both ladders and that they are duplicates of each other, I have shown only one of these supports and the corresponding ladder and adjacent end of the platform.

This scaffold comprises a pair of U-shape clamping plates 1-, each having a relatively short arm 2- and a relatively long arm 3 united at one end and spaced a sufiieient distance apart to receive between them one of the rails as a of the ladder A. These clamping plates -(i are, therefore, adjustable by slidii'ig up and down upon their respective rails and when adjusted for use are directly opposite each other'with their lower edges resting upon one of the rungs, as -a, of said ladder and their closed sides at the front engaged with the corresponding edges of the rail a, and their shorter arms preferably at the outside of said rails. The longer arms 3 of the clamping plates extend rearward beyond the corresponding edges of the rails and are provided with a plurality of sufiicient length to allow the clamping device to be placed in any position throughout the length of the ladder, which in most instances varies in width from end to end. One end of the bolt is provided with a head 6 and the other end with a nut 7 to hold it against accidental displacement from the clamping plates 1, and at the same time permitting it to be removed by simply unscrewing the nut 7' and withdrawing the bolt endwise from the plates, as for example in placing the clamping device upon and removing it from the rails of the ladder.

A pair of cam levers 8 are pivotally mounted upon opposite ends of the bolt just at the outside of and in close proximity to the longer arms 3 of the clamping plates 1-, so as to register with and frictionally engage the adjacent rear edges of the rails 1- for firmly clamping the plates in operative position upon said rails in adjusting the device for use. The plates 1, rod 5 and cam levers 8 are preferably made of wrought-iron or other strong and durable metal capable of withstanding the strains to which they may be subjected, but at the same time are of sufiicient light weight to enable the entire clamping device to be carried in the hand from place to place or assembled and adjusted upon the ladder to the desired position. In some instances, the lower and upper edges ofthe arms 3- at the inner side of the ladder rails may be provided with recesses 3f for engaging the rungs of the ladder, as shown in Fig. 3 to afford additional support for the clamping plates against forward and rearward movement, and at the same time permitting the clamps at different sides of the rails to be interchanged.

It will be seen from the foregoing description that therod 5 which is adapted to carry the entire load of the scaffold with the workmen thereon is supported in close proximity to the rails -a: of the ladder, leaving just sufficient space between the rod and rear edges of the rails a. to receive the cam levers 8, so that nearly the entire strain produced by the load is transmitted to the rails of the ladder in the direction of their length and downwardly, thus reducing the transverse strains upon the rails to a minimum which materially increases the safety of the entire apparatus.

When the main supporting rod 5 is securely attached to the ladder in the manner described, suitable tackle blocks are hooked thereon at any point between the plates 1, said tackle blocks being connected by a cable l() to another tackle block -11 which is attached to a bail l2 carrying a platform supporting-bar 13 of sufficient length to receive the adjacent end of the platform B between the ends of-the bail -12.

The bar 13- is preferably made of angle iron disposed with one of its sides in a horizontal position at the top to form a flat bearing face for the platform B, said top portion being provided with eye-bolts 14l to which the ends of the bail 12 are attached. This bar 13 is provided with a longitudinally adjustable extension 15 having its lower edge provided with a series of recesses 1(3 for engaging the rungs of the ladder which may be nearest in the horizontal plane of the platform, as shown in Fig. 1, the bar 13 and its extension 15 being provided with registering lengthwise slots 17 for receiving suitable bolts -l8 by which they may be held in their adjusted position, thereby constituting a brace connection between the platform B and ladder for holding the platform against swinging or swaying movement, thus further reducing the liability of accident. It is, of course, understood that when the platform B is brought to the desired height by manipulation of the cable 10, the free end of said cable may be tied in the usual manner to hold the platform in its adjusted position. It is also evident that as the platform is shifted vertically relatively to the ladder, the extension 17 may be adjusted. to bring any one of its notches -16 into engagement with the rung which may be in approximately the same horizontal plane as the platform, the object in providing the several notches to compensate for the limitations of adjustment of the extension --17- upon the bar 13.

Another feature of advantage of this particular form of ladder clamp is that the ladder may be brought closer to the building and the platform brought closer to the clamping device than would be possible if the rod 5 were not close to the rails of the ladder, or if it were necessary to use braces extending downwardly from the inner ends of the clamping Jlates l to the lower portions of the lad er rails.

The operation of my invention will now be readily understood upon reference to the foregoing description and the accompanying drawings, and it is evident that certain minor changes may be made in the details of construction of the various parts Without departing from the spirit of this invention.

What I claim is:

In a ladder scafiold, U-shape clamping plates hooked around one edge of the opposite rails of the ladder and having their inner arms extended beyond the opposite edges of the rails and provided With registering apertures, a rod having its ends supported in W said apertures, cam levers on the adjacent ends of the rod for engaging the corresponding edges of the ladder rails, a platform, and supporting means therefor attached to said rod.

In Witness whereof I have hereunto set my hand this 9th day of January, 1915.

' DAVID E. BROIVN. Witnesses:

H. E. CHASE, ALICE M. CANNON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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