US1171793A - Extension-ladder. - Google Patents

Description

G. J. KRBAVAC.

EXTENSION LADDER.

APPLICATION HLED JULY 30,1915.

Patented m. 15,1916.

l m-zl Witmoow g UNITED strArEs PATENT FFICE.

' GABRIEL J. KRBAVAC, 0F MELGHER, IOWA. v

EXTENSION-LADDER. j

Application filed. July 30, 1915., Serial No. 42,842.

To all whom it may concern: a I 7 Be it known that I, GAB IEL J. KRBAVAG, a citizen of the United States, residing at Melcher, in the county of Marion, State of Iowa, have invented certain new and. useful Improvements in Extension-Ladders; and I do hereby declare the following to. bee 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.

This invention relates to improvements in ladders, and particularly to extension ladders.

One object of the present invention is to provide an extension ladder which is simple and cheap in construction, and which is durable and efiective in use.

Another object of the invention is to provide an extension ladder which can be quickly and easily extended and collapsed, and which will occupy a minimum amount of space when so collapsed.

Another object of the invention resides in the novel means for extending and collapsing the ladder.

Other objects and advantages will be apparent from the following description when taken in connection with the accompanying drawing.

In the drawing: Figure 1 is'a front elevation of my improved ladder in extended position. Fig. 2 is a side elevation of' the same in the position of Fig. 1. Fig. 3 is a side elevation of the ladder in collapsed or folded position. Fig. 1 is a horizontal sectional view on the line 41 of Fig. 2. Fig. 5 is a longitudinal sectional view on the line 55 of Fig. 4. Fig. 6 is a transverse sectional view on the line 66 of Fig. &.

Referring particularly to the accompanying drawing, 10 represents a box or casing which is adapted to be mounted on a horse or motor-drawn vehicle. Mounted in the casing, and extending longitudinallythereon, is an oppositely threaded screw shaft 11, one end of which is provided with a crank handle 12 for rotating the shaft. A pair of blocks 13 and 14: are disposed in the ends of the casing, and are provided with interiorly threaded openings which the oppositely threaded portions of the screw shaft passes. Thus, by turning the crank handle the shaft will be rotated to move the blocks toward. and away fronr 15 through Specification of Letters Patent. 7 Patented Feb. 15 1916.

each other. Each of the blockscarriesa 2 pair of vertically extending apertured ears 16, andpivotally connected to each of these ears is the lower end of one of the links 17 of a lazy tongs 18. From an inspection of the drawing, it will be seen that there are two of thesela-zy tongs 18, thesame being arranged in parallel relation. Extending through the inner jointsof the links of the lazy tongs, and forming the pivots thereof, are the ends of the steps orrungs 19.

Connected to the upper ends of the lazy V tongs is a box 21, in which theperson, or

a persons, mountingthe ladder can seat or stand themselves, while manipulating any mechanism or apparatus, such as fire hose,

or tools used in repairing trolley or other overhead wires.

Carried by the block13 isa pair of brackets 22 which extend inwardly toward the block 14, and upwardly toward the ladder. On the free ends ofv these brackets 22 are mounted the pivotally arranged rock levers 23. At corresponding points on the block 14: are inwardly extending notched members 24, adapted to engage with the lower ends of the rock levers 23, when the blocks are moved into close proximity. Pivotally connected to the upper ends of the rock levers are the lower ends of the lowermost of the central vertical links 25,

which are pivotally connected together, as at 26 and centrally to the middle joints of the lazy tongs where they are provided with the rungs 20.

It will be seen that when the screw shaft is turned in one direction, that is to move the blocks toward each other, the lower,

ends of the rock levers will strike the members 2 1 and be rocked on their pivotsso that the links 25 will also be rocked on their pivots communicating this movement to all of the similar links 25 to the top of the ladder. It will of course,rbe understood that the links of the lazy tongs are rocked on their pivots to extend the same up into the air, in front of a high building or to an elevated suspended wire.

Attention is called to the fact that when. the ladder is in extended position, the rock' levers will engage with the members 24, and

positively hold the ladder against 001- lapsing. It will also be noted that when the blocks are moved away from each other, 7

the links 25 will be moved to break their joints'all the way up the latter, by reason of the fact that the rock levers are carried by the block 13, and move with it.

WVhat is claimed. is:

An extension ladder comprising a pair of. lazytongs, rungs connecting the oints of;

Copies 0: this patent may he obtained for carriedby'one of the sliding blocks, rock arms pivotally mounted on the brackets and each connected. at one end tothe lower end of each of the last-named links, and means carried by the other block for engagementzo with the other ends of the rock arms imparting an initial pivotal movement to the said links when the blocks are moved toward or away from each other.

In testimony whereof, Iafiix my signa- 25 ture, in the presence of two witnesses;

GABRIEL J KRBAVAG: Vvitnessesr AUGUST THOMAS," D. L. LECCOY.

fiife cents each-{115 aa'ares'sin the "commissioner or Pate-fits. Washington, D. C.

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