US559626A - Extension-ladder - Google Patents

Description

(No Model.) 2 Sheets-Sheet l D. SNELL. EXTENSION LADDER.

No. 559,626. Patente ay 5, 1896.

2 Sheets-Sheet 2.

(No Model.)

D. SNELL. EXTENSION LADDER.

Patented May 5, 1896.

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OTO-UTHO. WASHINGTON D r UNITED STATES PATENT Orrrcn.

DAVID SNELL, OF MIDDLEPORT, NEXV YORK.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 559,626, dated May 5, 1896- Application filed A il 22,1895. $erial No. 5%,749, (No model.)

To aZZ whmn it ntay concern:

Be it known that 1, DAVID SNELL, a citizen of the United States, residing at Middleport, in the county of Niagara and State of New York, have invented a new and useful EX- tension-Ladder, of-which the following is a specification.

This invention aims to provide an extension-ladder capable of general use which will be light, easily manipulated, and susceptible of beinglengthened and shortened with the greatest ease, and which can be used in orchards to enable any part of a fruit-tree to become readily accessible, and by builders, painters, firemen, and those whose occupation requires climbing to elevated points.

The object of the improvement is the provision of an improved structure and the combin ation therewith of a novel system of locking devices whereby the ladder-sections will be held at the extreme limits of their move ment, and which willbe automatically tripped to permit the folding and the ext-ending of the said ladder-sections when required, all as will more fully appear hereinafter.

For a full understanding of the invention reference is to be had to the following description. and the drawings hereto attached, in which-- Figure 1 is a perspective view showing the ladder extended. Fig. 2 is a longitudinalsection of the ladder, showing it folded and mounted upon a truck. Fig. 3 is a detail view of the locking mechanism for the laddersections and the releasing mechanism therefor. Fi g. 4 is a detail view of the lower catch. Fig. 5 is an enlarged detail view of an extensible brace.

In providing a ladder in accordance with the principle of the present invention any desired number of sections will be en'iployed, the number depending upon the capacity of the ladder and the required size of the same when reduced to a compact form. For the sake of clearness in illustration only three sections are shown in the present instance, numbered, respectively, 1, 2, and 3, said sections being of diminished width, so that the side pieces of the middle section 2 will come within the side pieces of the section 3 and the side pieces of sect-ion 1 within the side pieces of section 3. The several sections will be held in operative relation with one another by means of hooks at, which will be provided in sufficient number and properly disposed, so as to admit of the sections sliding the one upon the other and be retained in any position of their movements. The length and size of the sections are immaterial so far as the spirit of the invention is concerned. A Windlass 5 is located at the lower end of the section 3, which in practice is the lowermost section, and is designed to sustain the other sections when the ladder is suspended. The Windlass 5 is journaled in the side pieces of the section 3, and a sprocket-wheel G is mounted upon the projecting end of one of the journals to receive a sprocket-chain '7, which passes around the sprocket-wheel (5 and a corresponding sprocket-wheel S on a shaft 9, located a proper distance above the Windlass 5 and journaled in the side pieces of the section 3. The shaft 9 is rotated in any desired manner, preferably by means of cranks 10, one applied to each end, thereby rotating the sproclzetavheel 8, chain 7, and the Windlass 5. A rope or chain 11 is provided as a convenient means for extending or lowering the ladder-sections, one end being attached to the lower portion of the section 1 and passing over a sheave or pulley 12 at the upper end of the section 2, thence around a pulley or sheave 13 at the bottom of the said section 2 and over a come sponding pulley or sheave 1d at the top of the section 3, thence around the windlass 5, and having its opposite end attached to the upper portion of the section 1. In order to secure firm attachment between the Windlass 5 and the rope 11, the latter is passed around a drum on the Windlass 5 a sufficient number of times, so that when rotating the Windlass 5 in the manner set forth the rope 11 will be positively actuated and will move the ladd er-sections in the desired direction either to project them or bring the said sections into closed relation. In the event of a sprocketchain being used in place of the rope 11 the Windlass 5 will have a sprocket-wheel instead of the drum, and there will be no necessity for passing the sprocket-chain completely around the said Windlass to make positive engagement therewith, as the sprocket-wheel will have its spurs engage with the sprocket-chain and move the latter in a positive manner, as will be readily understood. The form of pulleys or sheaves for the rope or chain 11 to pass through is immaterial so long as they will subserve the purpose of reducing friction and admit of an easy and free movement of the said rope or chain at the turns or bights. A catch 15 is located near the upper end of the section 2 and is in the form of a bar, which has pivotal connection with one of the rungs by means of a clip embracing the said rung and having attachment with the sides of the said bar. A stop 16 is located opposite the catch 15,and a spring 17 is interposed between the catch 15 and the stop 16 and serves to project the free end of the catch outward, so as to engage with the lower end of the section 1 and support the latter when it reaches the limit of its upward movement. A plate 18, pivotedbetween its ends to the side piece of the section 2, bearing the stop and catch 16 and 15, has one end pivotally connected with the catch 15 and has a rod 19 attached to its opposite end and made fast at its lower end to a trip-lever 20. A catch 21 is located near the lower end of the section 2 on the same side piece with the catch 15 and consists of a strip of spring metal made fast at one end and having its upper portion bent approximately at right angles, as shown at 22, and operating through a slot 23 in the side piece of the section and having its inner end bent up, as shown at 23. This catch is adapted to engage with a notch 24, provided in the contiguous side piece of the section 3, so as to hold the section 2 in place until section 1 is fully extended. A bell-crank lever 25 is pivoted within the slot 23 and has one end connected with the trip-lever 20 by means of a rod 26, the opposite end being bent to engage with the bent end 23 of the catch 21, so as to disengage the catch 21 from the notch 24 prior to the upward movement of the section 2. A block 27 is made fast to the section 3 opposite the trip-lever 20 and is provided with a trip 28 to engage with the triplever 20 and operate the latter at the proper time to actuate the catches 15 and 21..

WVhen it is required to extend the laddersections, the Windlass 5 is rotated in the manner set forth, and the rope or chain 11 being set in motion causes an upward movement of the section 1 until the point of attachment of one end of the said rope or chain with its lower end comes opposite the pulley 0r sheave 12, when the catch 15 will move outward and come beneath the lower end of the section 1 and support the same. By reason of the connections between the catch 15 and the catch 21. the latter will be withdrawn from engagement with the section 3, and a continued movement of the rope or chain 11 will move the second section 2 to the required elevation. Any suitable means may be provided to hold the section 2 at any point of its upward movement. The spring 17 for operating the catch 15 is much stronger than the spring of the catch 21 and serves to project the catch 15 under the end of the section 1 after the latter has been extended, and also to overcome the tension of the spring-catch 21 and withdraw the latter from an operative position; but should the catch 2]. fail to be entirely disengaged from the notch 24: the subsequent action of the trip 28 on the trip-lever 20 will effect a release of the catch 21, so as to admit of the extension of the section 2. hen it is required to fold the ladder-sections after the latter has been extended, the rope or chain 11 is operated in a reverse manner from the movement required to extend the ladder.

The section 2, descending or folding first, 3

tion 1 will be permitted to hang loose, so as g to be drawn upon to extend the ladder-sections without requiring the application of the Windlass, as herein provided.

In order to sustain the ladder in an upright position, braces 29 are provided and suitably 4 connected at one end to the upper portion of the section 3 and are prevented from spreading too for apart at their lower ends by means of braces 30, which are formed of cord or rope. These braces 30 are attached at one end to the upper portion of the braces 29 and extend diagonally to the lower portion of the opposite braces 29 and pass through openings in the latter, thence upward and again through transverse openings formed in the said braces 29, the free end portions of the braces 30 being wrapped around the braces 29 and secured in any convenient manner. By lengthening or shortening the ropes or cords 30 the lower ends of the braces 29 can be spread a greater or less distance apart. Each of the braces 29 will be extensible to admit of its lengthening and shortening to suit the nature of the ground upon which the ladder may be used. For this purpose each brace will comprise sliding parts 31 and 32, the part 31 having a metal strip 33, provided at intervals in its length with openings 34, and the part 32 having spring-actuated bolt 35 to engage with one of the series of openings 34: and secure the parts 31 and 32 in the located position. A bell-crank lever 36 is pivoted in a mortise in the part 32 and is apertured at one end for the passage of the spring-actuated bolt 35 and is adapted to engage with lateral extensions 37 on the said bolt, so as to withdraw the latter from engagement with the part 31 when it is required to move the part 32 on the part 31. A hand-latch 38 is located on the part 32 and is connected by means of a wire 39 r with the spring-bolt 35, so as to operate the latter when required. The parts 31 and 32 are held together in any convenient manner, preferably by means of keepers 40, which are IIO secured to one part and are adapted to have the other part slide therethrough.

For general use the ladder can be handled in any convenient manner, but for special application, especially when designed for firemens use, it will be mounted upon a suitable truck in any convenient manner, as shown in Fig. 2, in which the numeral all indicates the rear wheels, 42 the front wheels, and 43 the pole or tongue by means of which the team is hitched to the truck for purposes of drawing the latter.

In constructing a ladder embodying the essence of the present invention to meet the various demands to which it is susceptible of application it will be readily understood that changes in the form, proportion, and the minor details of construction may be resorted to without departing from the principle or sacrificing any of the advantages of this invention.

IIavin g thus described the invention, what is claimed as new is- 1. In a ladder comprising sections which are adapted to slide the one upon the other,

the combination of upper and lower catches, a spring to move the upper catch in engagement with the upper section of the ladder when the latter is extended and at the same time release the lower catch so as to permit the release of the next ladder-section in the series, and a trip mechanism to withdraw the upper catch from engagement with the upper ladder-section when the ladder-section immediately below the said upper section reaches the limit of its downward movement, substantially as set forth.

In a ladder comprising extensible sections, the combination of means for extending the said sections, an upper catch to pro ject across the path of the top section and support the latter, a lower spring-actuated catch to hold the section immediately below the top section until the latter reaches the limit of its upward movement, a spring for 45 acting upon the upper catch to move the same across the path of the top section and at the same time overcome the force of the lower catch and release the latter to admit of the second section of the series moving upward, a trip '-lever having connection with both of the catches, and a trip to engage with the trip-lever and actuate the catches, substantially as described for the purpose set forth.

3. In a ladder comprising extensible sections, the combination of means for raising and lowering the said sections, an upper catch comprising a bar having pivotal connection to a rung of the ladder, a stop opposite the said catch, a spring interposed between the stop and catch, a pivoted plate connected at one end with the said catch, a trip-lever having connection with the opposite end of the said plate, a lower springactuated catch 6 5 adapted to hold the ladder-section until the section immediately above the same is fully extended, a bell-crank lever adapted to engage with the said spring-actnated catch, and having its opposite end connected with the said trip-lever, and a trip adapted to engage with the trip-lever when the ladder-section carried thereby has nearly reached the limit of its downward movement, whereby the said upper catch is withdrawn from an operative position to permit the lowering of the top section, substantially as set forth.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature in the presence of two witnesses.

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