US623476A

US623476A - Extension-ladder

Info

Publication number: US623476A
Authority: US
Publication date: 1899-04-18
Anticipated expiration: 1916-04-18

Description

(No Moder.)

lfv i.

Ms E 7 Q a" I w TNESSI J. R. JONES. EXTENSION LADDER.

(Application filed June 6, 1898.)

THE Norms PETERS co. moraumo. WASH\NGTQN. u. c.

Patented Apr. l8, I899.-

ihvrrap STATES PATENT @rricn.

JOHN R. JONES, OF OSI-IKOSH, WISCONSIN.

EXTENSION=LADDER.

SPECIFICATION forming part Of Letters Patent NO. 623,476, dated April 18, 1899.

Application filed June 6, 1898. Serial No. 682,749. (N0 model.)

T0 to w/wm it may concern: I

Be it known that I, JOHN R. JONES, a citizen of the United States, residing at Oshkosh, in the county of IVinnebago and State of Wisconsin, have invented new and useful Improvements in Extension-Ladders, of which the following is a specification.

My invention relates to improvements in extension-ladders; and it consists in certain construction and arrangement of parts,which will be more fully hereinafter set forth.

The objects of my invention are, first, to provide a simple and safe means of operating an extension-ladder and of holding the extensible portion firmly at any desired altitude, and, second, to provide a safe and efficient means of attaching the hoisting-rope to either or any of the ladder-rungs and of detaching the same therefrom.

Inthe accompanying drawings, Figure l is a rear View of the ladder. Fig. 2 is a vertical section across the ladder. Fig. 3 is a detail view of the latching device. Fig. 4 isa crosssection showing one of the yokes, and Fig. 5 is a representation of my device for fastening the hoisting-rope to the ladder-rung.

- Similar letters refer to similar parts in each vlew.

A represents the lower section of the ladder, and B represents the upper extensible section, which slides within the lower section between the rungs a a, &c and the yokes C C. It will be observed from the drawings that both ladders A and B are rung-ladders. In ladders a distinction is made between run gladders where the rungs or rounds are attached to the side rails centrally and cleatladders where the cleats are nailed to the edges of said rails, the rung-ladders being considered superior to the cleat-ladders and more durable.

My invention provides a means of extension, so that both the main ladder and the extensible portion may be rung-ladders.

An important feature of my inventionis the latches D D, which are mounted upon the revoluble rung Ct, one latch at each side of the ladder, Fig. 1, rigidly attached to said rung a and revolving therewith, said latches being similar in construct-ion,except that one of them, D, is provided with an upwardly and outwardly extending arm E, to which the trip-rope F is attached, which trip-rope operates by pulling downwardly to revolve the latch D and raise the opposite end cl to open the latch. The latch is closed by the action of the coil-spring G, which is rigidly attached to the rung a, being coiled around the said rung, and the opposite end bears on one of the cross-bar supports H H, as at a. The opening of the latch D serves to compress the coil-spring Gr, and when the triprope is released the pressure of the spring revolves the rung a and forces the latch D downwardly to the position shown in Fig. 3 and retains it in said position.

I do not regard the use of the spring G as essential, as the latch will drop to close it by gravity alone. A lug may be provided to prevent its revolution beyond the perpendicular when opened by the trip-rope, so that gravity alone will operate it; but the use of the spring insures its downward return to close the latch and is advisable for that purpose and to render the operation of the latch absolutely certain.

The latch when closed at the position shown in Fig. 3 may support either or any of the rungs b I) b of the extension portion of the ladder, and thereby retain that portion of the ladder at any desired extension.

I am aware that extension-ladders have heretofore been supported by different forms of hooks and dogs engaging the rungs of the ladder; but they have been unreliable and not as durable or as strong as the latch pro vided in my invention. An essential feature of an extension-ladder should be its absolute safety in latching and strength in support. For this purpose I provide below each latch a supporting block or post I, securely attached to the cross-bars 1-1 H, extending across the main ladder and rigidly attached to the rail. The blocks or ports I thus furnish an absolutely safe and secure support for each latch D D when closed, as shown in Fig. 3. The latch rests directly upon the blocks or posts I and supports at its outer end the rung b. The outer end of each of the latches D D is curved upwardly, so that the latch opens and closes automatically as the rungs b b, 850., pass by it in raising the extension. The

extensible portion is raised by means of the continuous hoisting-rope J, which passes over the pulley K, hung from the upper yoke C. It is necessary that the continuous rope J be attached to the extensible ladder and is preferably attached to one of the rungs. For this purpose I provide a worm fastener M, as shown in Fig. 5, which consists of a wire coiled at each end m m and the central portion m curved in semicircular form corresponding with the size and shape of the ladder-rung, so as to partly surround it in the adjustment of the fastener. In adjusting the fastener the rope is first rapidly wound in the lower coiled end 772/, then passed around the rung on the side opposite to the wire, and rapidly wound in the upper coiled end m This provides a hug of the rope around and against the ladder-rung and against the wire in both the upper and lower coiled ends. The greater the pull upon the rope the stronger becomes the tension against the ladder-rung and the upper and lower coils of the fastener. By means of this portion of my invention the rope may be rapidly and securely attached to or detached from any rung of the ladder.

In operating the ladder I pull downwardly upon the hoisting-rope J, and thus raise it, the extensible portion sliding upwardly within the main portion B and resting upon the rungs a a c, the. As each rung b l) strikes against the curved end of the latch d it raises it slightly, sufficient for the passage of the rung, and the latch then immediately is returned to its position by the spring G, so that at any time when the hoisting-rope is released the extensible part of the ladder will descend until the nearest rung b above rests upon the latches D D, thus supporting the upper ladder, the inner edges of the rails resting upon the rungs a a a, &c., and the outer edges of the rails bearing against the double yoke C (J. In order to lower the extensible portion, it is first necessary to raise it slightly by pulling upon the rope J sulficiently so that the latches D D will clear the rung I). Then I pull downwardly upon the trip-rope F, revolving the latches to the dotted position shown in Fig. 3, when by releasing the hoisting-rope J the extensible portion of the ladder is permitted to drop (lownwardly to the bottom or until the triprope is released to close the latch. The upward-curved end of the latch is important, further, in that it serves to bind the two parts of the ladder together, and thereby make it more rigid and prevent side swaying. The weight of the extensible portion presses downwardly upon the curved end cl toward the rungs a a (L, &c., of the main ladder and causes the rails of the extensible portion to bear tightly against said rungs and bind the two sections together, as stated. The use of the double yoke O C upon the front of the ladder provides a simple way for the sliding of the upper portion and a double support for the ladder when extended, also enabling the use of rung-ladders for both the main and the extensible portions. The yokes consist of slats c c, resting upon the knees c c and secured to the rails of the main ladder A by means of clips it, which pass over and around the yoke and knees and through the said rails of the ladder and are secured beneath, as shown in Fig. 4.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an extension-ladder, the combination of a stationary section, and a movable section, a revoluble rung inthe stationary section, having arms forming latches, means for returning the latches to their normal positions, a rope for operating the said rung and latches, and an endless hoisting-rope connected to the sections of the ladder for raising the movable section, substantially as described.

2. In an extension-ladder, the combination of a stationary section, and a movable section, a revoluble rung in the stationary section, having arms projecting therefrom and forming latches, a spring for returning the latches to their normal positions, another arm on one of said latches, a rope connected therewith for operating the rung and latches, and an endless hoisting-rope connected to the sec tions of the ladder for raising the movable section, substantially as described.

3. In an extension-ladder, the combination of a stationarysection, and a movable section, a revoluble rung in the stationary section, having arms projecting therefrom and forming latches, a spring upon the said revoluble rung for automatically returning the latches when in adisengaged position, the said spring bearing at one end upon a cleat on the ladder, a rope for operating the rung and latches, and a hoisting-rope connected to the sections of the ladder for raising the movable section, substantially as described.

4. In an extension-ladder, the combination of a stationary section, and a movable section, a continuous hoisting-rope connected to' the sections of the ladderand means for connecting said hoisting-rope to one of the rungs of the movable section, said means comprising a worm-fastener made in the form of a coiled wire with a central curved portion to receive the said rung, the hoisting-rope being wound in the coiled portions of the wire and passing on one side of the rung of the ladder, substantially as described.

5. In an extension-ladder, the combination of a stationarysection, and a movable section, an endless hoisting-rope attached to the movable seetion for raising the same, and a wormfastener for attaching the said rope at any point on its length to any rung and comprising a rung-hugging portion and spirals adapted to extend upon each side of the rung whereby the rope may be quickly wound or unwound so as tobe firmly secured to or easily to their normal positions, a hoisting-rope for removable from the said rung", substantially operating the movable section, substantially as described. as described.

(3. In an extension-ladder, the combination I In testimony whereof I have hereunto set 15 5 of a stationary section and a movable section, my hand in the presence of two subscribing latches pivoted on the stationary section and Witnesses. having their outer ends turned upwardly, blocks or posts secured to the ladder and arranged longitudinally thereof for supporting WVitnesses: lo the latches, a rope for operating said latches, HENRY HENKEL, ineansfor automatically returning the latches l F. J. MCKENNEY.

JOHN R. JONES.