US1031818A - Extensible ladder. - Google Patents

Description

L. S. PUTMAN.

EXTENSIBLB LADDER.

APPLIOATION FILED 11110. '1, 1911.

Patented. July 9, 1912.

2 SHEETS-SHEET 1.

I Patented July 9, 1912.

MI. W m /w m a l li I w M m l ll w members of U-shaped bars, the.br-idges of LEWI SfS PUTMAN, 0F STACY, TEXAS5'ASSIGNQR OF ONE-THIRD TO M. JISTAGY AND i ONE-THIRD TO E. TROTT, BOTH 0F STACY, TEXAS.

Ex'rEnsIBLE LADDER.

To allwk-om it may concern:

Be it known that I, LEWIS S. PUTMAN, a citizen of the United States, residing at Stacy, in the county of .McCulIoch, State of Texas, have invented certain new land useful Improvements in Extensible Ladders; and; I do hereby declare the following tofv be a i full, clear, and exact description of the in-- vention, such as will enable others skilled; in the art to which it appertainszto make and 7 nected to a'slide bar 16 which extends transuse the same.

This invention relates. tofexteiision ladders f of lazy-tong structure and has for an object;

to provide a ladder on each side of the structure, this being accomplished by forming the the bars serving as ladder steps.

'A further object of the invention is to provideja platform which when-the struc ture ise'xtended will drop downbetween the 'bridges of the uppermost bars of the structure so that the bridges form guard rails for the platform. V

A still further object of the invention is to so secure the'platforni that it will at 'all times rest upon the common pivot of the uppermost U-shaped bars so thatthe pivot forms a support for the platform;

With the above objects in view the invention consists of certain novel details of construction and combination of parts herein after described and claimed, it being understood that various modifications may be made in the minor details of construction within the scope of the appended claims.

In the accompanying drawings forming part of this speeificat1on:Figure 1 is a perspective view of the extensible ladder in operative position. Fig. 2' is a side elevation of the ladder in collapsed position.

Referring now to the drawings in which like characters of reference designate similar parts, the ladder is shown to comprise a lazy-tong strpcture formed of substantially U-shaped bars 10 the legs of each bar being terminally connected to the legs of the next adjacent bar in close proximity to the:

bridge thereof by pivot pins 11, and the centrally intersecting portions of the legs of the bars being connected by common pivot pins 12. When the lazy-tong structure is extended, the bridges of the U-shaped bars form ladder .steps on each side of the structure, and furthermore the extending movement of the structure is limited bycon Specification offLetters Patent.

tact of-the arenas of each'bar legs with Patented J my 9, 1912. Application filed December 1, 1911. SerialNo. 664,383.

3 the bridge of the adjacent bar sothat chains v and similar devicescommonly used to ati in this end are entirely dispensed with.

The terminals of one of the. lowermost by-pivot pins 13 to the spaced sides 14 of a skeleton .truckwhich is designated in gen- 1 the other lowermost bar are pivotally; conversely across the truck'and issec'ured to the ,sides thereof through theinstrumentality of strap guides 17 disposedupon the top edges of the truck sides. Upstanding ears 18 are formed. on the slide bar and between these ears the terminals of the last named lowermost bar are passed and pivotally connected to the ears through the instrumentality of pivot pins 19. r r j A Windlass for actuating the slide baris .disposed upon the truck and'comprises a shaft 20 'the. 'opposite ends of which are 'journaled in suitable bearings 21 mounted upon the top edges of the truck sides, one

end of the shaft being equipped with a crankhandle 22. A pair of chains .23 or' similar flexible connectors are connected to the shaft and to the slide bar and upon rotation of the shaft these chains are wound eral by the numeral 15. Theterminals 'of- 6'5 6f! ars of the structure are pivotally connected so V tion of theshaft thus extending the lazy- Y the shaft and a pawl 25 is pivotally attached to the outer face of the adjacent disk and facilitate gradual collapse of the I lazy-tong structure after the pawl has been disengaged from the ratchet wheel.

-A platform 30 is suspended from the legs of the uppermost bars ofj the structure through the instrumentality of short lmks 31 which are pivotally oposite ends to the sides of the platform and the legs of.the bars near the bridges truck side and operatively engages the connected at their thereof. The links are of such length. as to permit of ,the platform permanently resting upon the common pivot 12 of the uppermost bars so that this pivot cooperates with the links in supporting the platform. 'It

will be noted that by virtue of this arrangement; the bridges of the uppermost bars ex tend above the platform when the lazy-tong structure is extended and form guard rails for the platform. A handrail 32 is secured to the platform through the instrumentality of posts 33. It will be noted that by virtue of the platform being supported by the common pivot of the uppermost bars, swinging of the platform Whena person steps upon it I is positively prevented.

What is claimed, is v v 1. A ladder of lazy-tong structure comprising U-shaped bars, the legs of each bar being, terminally pivotally connected to the legs of the next adjacent bar near the bridge thereof,. whereby said bridges form ladder short links pivotally connected at t steps and further contact with the terminals of the next adjacent bar legs and limit ex-' tending movement of the lazy-tong structure. i 2. The combination of a ladder of lazytong structure comprising crossed bars operatively connected together, both pairs of the uppermost crossed bars of the structure Intestimony whereof, I afiix my signature, in presence of two witnesses.

LEWIS S. PUTMAN.

Witnesses:

FRANK LACY, CLARENCE TROTT.

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