US242114A - Extension-ladder - Google Patents

Description

(No Model.) a sheets-sheet 1.

J. L. CRAFTS. Extension Ladder.

No. 242,114. Patented May 31, I881.

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(N 0 Model.) 8 Sheets-Sheet 2.

J. L. CRAFTS. Extension Ladder. Ng. 242,114. Patented May 31, 1881..

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Extension- Ladder.

No. 242,114. Patented May 31, I881.

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PATENT ()FFIcE.

JOHN L. CRAFTS, on S'oMnnVILLE, MAssAonUSETTS.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 242,114, dated May 31, 1881.

Application filed June 10,1880. (N6 model.)

To all whom it may concern: y Be it known that I, JOHN L. CRAFTS, a citizen of the United States, residing at Somerf ville, in the county of Middlesex, State of Mas-.1 sachusetts, haveiuvented certain new Improvements in Extension-Ladders; and I hereby de-; clare the following to be a full, clear, and exactl description of the invention, such as will enable others skilled in the art to which it apper-f This invention relates to extension lad-g ders, so called-that is, ladders capable of expansion and contraction in the direction of f their length, and adapted for firemens use in extinguishing fires or for other purposes.

Minor details of my improvements will bej duly explained hereinafter.

The drawings accompanying this specifica-l tion represent, in Figure 1, a central vertical! longitudinal section of my ladder Figs. 2 andi 3, central vertical longitudinal sections of rearf and front ends respectively, while Figs. 4 and? 5 are plans of the front and rear ends of thej same ladder. Fig. 6 is a side elevation of ladder in erect position and ready for use. p

In the above-named drawings, A represents a truck of a size and form to adapt it to they purpose of supporting a heavy ladder, such" truck being composed of a rectangular framej B, mounted upon axles and wheels 0 G and} D D D D, and provided with a pole for attachment of the draft-horses, a brake, E, being combined with the hind wheels, D D, to prevent movement of the truck while the lad der is erected.

Upon the rear part of the truck-frame I erect a standard or frame, E, composed of two triangular-shaped housings, F F, connected with? the truck by a transverse horizontal pivot, (if in such manner that the standard may be turned upon such pivot and lowered into a horizontal position, in which event its free end overhangs the rear ends of the truck, and,'in conjunction with a horizontal cross bar or roller, 11, mounted in standards 0 c erected upon the front end of the truck,constitutes a long and efficient bearing for the ladder when the latter is folded and lowered into the position it occupies when not in use. When in its lowered position the rear or longer side, 01, of the standard E rests upon the rear end of the truck, and, in conjunction with this bearing and its own pivot, serves to i uphold the greater part of the weight of the ladder, the forward end of the ladder at such time resting upon the roller b, before named. When the standard E is in an upright position its shorter side or base 0 rests upon the top of the truck and serves to support the weight of the ladder as it is being raised or lowered in a contracted state, or while being extended or contracted in length after being raised.

The main portion or section of the ladder is shown at G as composed of two pairs of rails, H H H H, all united by the rungs or rounds ff, 860., the inner rails, H H, serving not only to greatly stiffen and strengthen the main section of the ladder, but as a support, each for i a metallic plate or bar, I I, which is secured to its outer face, each plate I overhanging the inner edge of the rail, as shown at 9, while beneath or inside each of these plates is a lug, h,

extending laterally from the lower end of the sliding or extension section J of the ladder. As the section J is raised or lowered the lugs h h slide beneath the plate or guides I, and

i serve to insure connection of the two sections of the ladder. The main section of the ladder is provided with suitable side trusses, L L, and it is pivoted at about one-third its length from its lower end, by a horizontal rod or pivot, i, to the upper part of the standard E ,in such manner as to be capable of swinging upon the latter.

The rails of the sliding or extension section of the ladder areshown at N N, and its rounds at K K, &c;, and its said rails N N are provided with trusses l I, after the manner of the main section.

The lower end of the extension J is confined to the main portion of the ladder by the lugs and plates I I and h h, before explained, while to provide at the upper end of the main sec tion a device to prevent separation of the two sections, and to' guide the extension as it is being raised or lowered, I secure to the upper end of the said main section cars at m, which overlap the outer surfaces of the rails N N. These ears permit of passage of the trusses 0f the extension as the latter is being raised or lowered, which would not be the case if a bar uniting the two rails of the section was employed. The trusses at the lower end of the extension J of the ladder pass over or are socured to the outer ends of braces or arms a 12, secured to the lower end of said extension, while the trusses at the upper end of the main section of the ladder are secured to like arms, 0 0, aiiixed to said main section, the two pairs of arms being so arranged with respect to each other that as 'the extension reaches its highest position the arms interlock and the trusses of the two sections of the ladder virtually become one, to stiffen the whole.

To one of the lower rounds of the extension J, I pivot a dog, a, composed of two side cars, 1111, united by a cross-bar, q, the width of the cars at their lower ends being such as to intercept the rounds of the main section of the ladder, and by resting upon some one of such rounds support the extension as it is raised. As the extension is raised the dog passes over each rung in succession of the main ladder and drops between the one last passed and the one above next succeeding, thereby arresting descent of the extension. To hold the dog out of engagement with the rounds of the main section, when the extension is to be lowered, I pivot to the adjacent part of one of the rails N of said extension a latch, r, in the form of a bell-crank lever. 1y pushing one arm of the latch r beneath one of the ears of the dog the latter is restrained from engaging the rounds of the main ladder.

The hoisting apparatus, for elevating the extension J upon the main portion of the ladder,

consists of an endless chain or rope disposed at each side of the main section and between its side rails, such endless chain or rope being secured at some suitable point to the extension, and passing about driving-pulleys s s, secured to a shaft, I, mounted in the lower part of the main ladder, and also about idle-pulleys u u, pivoted to the upper part of the main sec tion, the shaft 1 being provided with a crank, c, for rotating it. Rotating the shaft t in one direction effects the elevation of the extension upon the main section, while a reverse movement of the shaft allows the extension to lower by its own gravity or, in case of necessity, the shaft and rope may be used to pull the extension part down.

The main windlass, before alluded to, is shown in the drawings as composed of a hori zontal drum, 1e,journaled to the upper part of the truck, and carrying at one end a spur-gear, x, which engages apinion, y, fixed to the adjacent end of a horizontal shaft, 2, also journ aled to the top of the truck and disposed alongside of and parallel with the drum, the said shaft carrying at its opposite end a ratchet-wheel, a, which operates with a pawl, I), pivoted to the adjacent part of the truck-frame to preventfallingof the ladder while it is being raised by and with the swinging standard, or being elevated into a vertical position after the latter has been brought to an erect position. Ropes c d extend from each end of the drum outward to and are connected with the lower end of the ladder, preferably passing over a horizontal beam, 0, which spans the base of the standard E, and which constitutes one of the points of support of the ladder while the latter is in a recumbent position.

The secondary windlass, before alluded to, is shown as composed of a horizontal drum, journaled, as shown at g g, to the upright standards 0 0, before mentioned as erected upon the front part of the truck, a rope or chain, It, being secured at one end to the drum, and partially coiled about the latter, and thence extending to and being connected with the extreme outer or upper end of the extension J, onejournal of thedrumf beingprovidcd with a crank.

The operation of my ladder is as follows, it being supposed that it is in traveling condition, as shown in the drawings: If it is to be used at a burning building, the truck is driven up to the burning building, the horsrs are removed, and the brake applied to the hind wheels, after which the ladder is set in motion. Two men or more are essential to properly operate the ladder, and one seizes the crank of the main windlass and the other that of the secondary windlass, and the pawl b is dropped into engagement with the teeth of the ratchet-w heel a. By means ofshaftz the drum w is now turned to the left and the standard E raised to an erect position, the rear end of the ladder being raised with it, while the front end of the ladder rests upon the roller 11. The guy rope orehain It, being kept constantly taut by the other man, prevents the tendencyof the ladder to slide forward from elevating the standard too suddenly. The drum to is now turned in the same direction until the ladder is rotated upon its pivot i and brought from a recumbent to an upright position, the guy-rope being kept taut during this movement by a pawl and ratchet, with which it is provided. The ladder is now available for an ordinary height-say fifty feet; but if a greater height is to be attained, the shaft t is to be rotated in the right direction, which hoists the extension J upon the main section to the desired height; and to alter the an gle of the main ladder the main drum is released from the restraint of its pawl, to permit of a less elevation of the main section, and returned to place when said section is to be elevated or raised nearer the perpendicular. The guy-ropes, as before stated, serve to prevent swaying of the upper portion of the ladder.

To contract the ladder preparatory to removing it from the place it occupied, the extension is lowered upon the main section by the rotation of the shaft 25, and the crank of the drum w is again seized, its pawl removed from ratchet-wheel, and the ladder is allowed to lower by its own gravity to and upon the roller I), the slack of the guy-rope It being taken up by rotating the drum f in the proper direc tion, it being observed that the said guy-rope passes from its drum upward over the roller 0, thence horizontally outward to the end of the ladder. The drum f is now rotated to the right or toward the rear of the truck, and the tension upon its rope forces the ladder rearward until the pointof equilibrium of the standard E is passed, when the standard and ladder drop together by their combined gravity to a seat upon the rear end of the truck, the drum to being restrained from turning rapidly, in order to prevent too sudden descent of the ladder.

It will be seen that by pivoting the ladder to the swinging standard, as explained, I am enabled, when the standard is raised, to obtain a very firm bearing for the ladder, from the reason that the pivot which constitutes the hearing is situated at a considerable distance from the bottom of the ladder, and for the same reason I obtain a long leverage or purchase, by which I am enabled to raise my ladder into an erect position with little power. At the same time I am enabled by pivoting the standard to the truck to lower the ladder to the top of such truck when it is to be transported.

By the employment of hoisting chains or ropes on both sides the ladder to elevate the extension, in lieu of a single one in the center, as has heretofore been the case, I am enabled toobtain great, and insure smooth and steady, movement of such extension.

In preparing to erect the ladder I raise and advance the foot of the ladder first, which is a considerable. advantage.

By hoisting the extension round by round upon the main section I am enabled to increase the length or height of the ladder to a small extent, as may be desired, in lieu of increasing its length by the addition of a whole section.

Although I have described my invention as a ladder, it is evident that its principle of operation will be applicable to derricks with equal advantage, and do not restrict myself to a lad der so long as the invention is applicable to either.

. Having thus explained the naturc,purposes,

and advantages of my invention, I claim and desire to secure by Letters Patent of theUnited States as follows:

1. The combination of the ladder, the truck, and an intervening ladder-supporting standard hinged or pivoted to the truck, such standard carrying the pivotal point of the ladder, and being adapted to raise and lower said ladder with respect. to the truck and before it is elevated to an erect position, substantially as stated.

2. The combination of the truck, the standard hinged or pivoted to the truck, the extension-ladder hinged or pivoted to the standard, and the main and secondary windlasses.

3. The two sections of the ladder with their respective trusses adapted to interlock when the ladder is fully extended and constitute practically a continuous truss, substantially as stated.

4. The standard hinged to the truck, adapted while in an erect position to provide a bearing for the ladder at a considerable elevation above the truck and the ground, and while in a lowered position to bring the ladder as closely as possible to the truck for ease and safety in traveling, substantially as stated.

5. In combination, the hinged standard, the two sections of the ladder, the truck with its elevated roller or bar I), and the secondary Windlass, substantially as described.

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

I JOHN L. CRAFTS.

Witnesses:

H. E. LODGE, F. CURTIS.

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