US423989A

US423989A - Scaffold

Info

Publication number: US423989A
Authority: US
Publication date: 1890-03-25
Anticipated expiration: 1907-03-25

Description

(No Model.)

B. J. O RUMP. SOAPPOLD.

No. 423,989. Patented Mar. 25, 1890.

iiiiorne UNITED STATES lATENT OFFIcn.

ROBERT J. CRUMP, OF OWENSBOROUGH, KENTUCKY.

SCAFFOLD.

SPECIFICATION forming part of Letters Patent No. 423,989, dated March 25, 1890.

Application filed December 16, 1889. fierial No. 333,918. (No model.)

To all whom it may concern:

Be it known that I, ROBERT J. CRUMP, a citizen of the United States, residing at Owensborough, in the county of Daviess and State of Kentucky, have invented certain new and useful Improvements in Scafiolds; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention has relation to certain new and useful improvements in scaffolds for the use of painters, brick-layers, and others; and it has for its object among others to provide an improved device of this character which shall be simple, easily operated, and durable.

The novelty in the present instance resides in the peculiarities of construction and the combinations, arrangement, and adaptation of parts, all as more fully hereinafter described, shown in the drawings, and then particularly pointed out in the appended claim.

The invention is clearly illustrated in the accompanying drawings, which, with the letters of reference marked thereon, form a part of this specification, and in which Figure 1 is aperspective View of a scaffold constructed in accordance with my invention.

Fig. 2 is a detail which will be more particularly hereinafter referred to.

Like letters of reference indicate like parts throughout the several views.

Referring now to the details of the drawings by letter, A designates suitable uprights suitably braced or supported at their lower ends, and also by means of the longitudinal pieces A, which are adjustably held to the uprights by means of the thumb-bolts a, passing through the elongated slots in the ends of the said longitudinal pieces. The upper ends of each set of uprights is preferably braced by a cross piece or cap A Near the upper ends of these uprights beneath these caps are journaled the rollers or drums B, provided near each end with a circumferen tial groove 1), in which the hoisting ropes or chains are designed to work. These rollers or drums taper slightly from the inner wall of the grooves toward the center of the roller or drum, as shown clearly in Fig. 1, for a purpose hereinafter made apparent. Near the lower ends of the uprights are journaled the larger drums 0, each having an extended end provided with a crank and handle 0, by means of which the said drums maybe caused to revolve when it is desired to elevate the platform.

The platform D consists of the transverse timbers D, having their ends cut away to embrace the uprights, and are thus guided in their vertical movement, and the longitudinal timbers D connecting said transverse timbers and attached thereto in any suitable manner. This platform is designed to receive the material and the laborers, and is elevated in the following manner: E are ropes or chains, two at each end of the scaffold, one end of each rope or chain being attached to the lower drums, and after passing over the upper drums are secured to the transverse end tim bers of the platform. The turning of the cranks on the extended ends of the journals of the lower drums causes the platform to rise. In order to prevent retrograde movement of the platform, I provide upon one end of each of the lower drums a ratchet-wheel F, with which is designed to engagea gravity pawl or dog G, pivoted to the inner face of the uprights at that side of the scaffold. As the platform rises the dogs automatically engage the teeth of the ratchet-wheel and prevent retrograde movement of the platform and drums. These dogs are upon the inner faces of the uprights, where they are not liable to injury. The taper of the upper drums or rollers from each end toward the center is deemed of special importance, as it serves to draw the ropes or chains toward the ends of the rollers into the grooves therefor, and thus prevent overrunning or interfering of the two ropes or chains which travel or work on each upper drum or roller. If the cords or chains should get out of their grooves in the lowering of the platform, as is liable sometimes to occur, they will be automatically drawn outward away from each other as the platform is elevated.

What is claimed as new is- The combination, with the uprights and the each end of the platform, substantially as IO vertica1ly-1n0vable platform, of the lower shown and described, and for the purpose drums jonrnaled in said uprights and prospecified. vicled with cranks upon their extended ends, In testimony whereof I aifix my signaturein 5 the cords or chains attached at one end to presence of two witnesses.

said platform and at the other to the lower ROBERT J. CRUMP. drums, and the upper drums j onrnaled in said Witnesses: uprights and tapered from their ends toward J. D. ATCHISON,

the center, and over which pass two cords at THOS. R. HIGGINS.