US382871A - Extension-ladder - Google Patents

Description

Patented Maly 15, 1888.

JAMES C. GARDNER, OF CHICAGO, ILLINOIS.

EXTENSIONeLADDER.

sPnerrrcATIoN forming part of Letters Parent No. 382,871, dated May 15,1888.

Application nien May 12, resi. serial No. 237,972. (no masi.)

To all whom t may concern.-

Beit known that I, .latins C. GARDNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in EXtensionLadders; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art t-o which it appertains to make and use the same, reference being had to the accompanying drawings, and. to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to portable extension-ladders in which a movable section overlies the section standing on the ground, and is adapted to be moved upwardly through varying distances over the lower section, thus increasing the length ofthe ladder.`

The object ot' my invention is to provide for an easy action of the movable section. The manner ofaecomplishing this will appear from the following description.

In the accompanying drawings, Figure l is a perspective view of my improved ladder. Fig. 2 is a vertical section. Fig. 3 is a transverse section.

A is the lower section of the ladder. It is composed of the side rails,AA,aud rungs A2.

B is the upper and movable section, composed of the side rails, B B', and rungs B2. Said section B is sutciently narrow to lie loosely between the side rails and upon the rungs ofthe section A.l

C C are swinging stirrups attached to the outer sides of the side rails ot' the section B, and constructed to engage the rungs A2 from above, thus retaining the section B in its elevated position.

D is an iron yoke extending transversely over the section B and fixed by its ends upon the side rails, A A.

The parts thus far mentioned have been heretofore used and are not my invention. The yoke D has been placed near enough to the section B to serve as a guide and stay for the latter. As the section Bis pushed upward by a man standing upon the section A,the upper end of section B resting meanwhile against a wall or other object, the yoke D binds upon the front 'sides of the rails B B so tightly that in many cases it is impossible for the man to raise the section. To obviate this difficulty I lengthen the arms D D' of the yoke D sufficiently to make room for the roller E between the yoke and the front faces ofthe rails BB. Said roller is preferably long enough to reach from onev arm D to the other, and is hollow through its axis to receive and be supported by the bolt or shaft F, the latter having its ends secured in the arms D' D. In pushing upward on the section B the roller Eturns readily and allows the section to be moved with ease. It has been heretofore attempted to attain this result bythe use of a roller located over each rail B B and supported by a bracket attached to the side rails, A A', but this construction has been defective and unsatisfactory, for the reason that under strain the brackets would yield laterally and allow the upper section ot' the ladder to become displaced. This would result from the weakness of the brackets themselves and their attachment to the side rails and from the itlexibility of the rails. By combining the yoke, rails, shaft, and roller as I have described, the roller is so rmly supported that it will not yield under any strains to which it is subjected in use.

I claim as my invention- The combination of the sections A and B, the latter lying upon the rungs and between the side rails oll the former, a yoke, D, extending transversely across said section Bi, and h aving its arms D D passing along the side rails of said section, and secured to the side rails ofthe section A,and joined above such section B by a shaft, F, extending from one to the other, a roller loosely surrounding said shaft, and stirrups C C, to engage the rung-s A2, substantially as shown and described.

In testimony whereof I aftix my signature in presence of two witnesses.

JAMES C. GARDNER. Vitnesses:

Giras. Fllwnns, @nannies H. Renners.

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