US675744A - Extension, step, and scaffold ladder. - Google Patents

Description

No. 675,744. Patented lune 4, I901. M. J. LEWIS. EXTENSION,STEP,AND SCAFFOLD LADDER.

(Application filed May 31, 1900.) (No Model.) 2 Sheets-Sheet I.

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No. 675,744. Patented June 4, MN. M. J. LEWIS. EXTENSIUN,STEP,AND SGAFFOLD LADDER.

(Application Med May 31, 1900.) (No Model.) 4 2 Sheets-Sheet 2.

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. EXTENS ION," TEP;l-tN bisAF o DDE SPECIFICATION rmin at is Letters rat -15x6. 675.744, dated J'nne 4, 1901.1 I

Application filed m 31,1909.

To all whom, it mayconcern; v v Be it known that .I, MELVIN J. LEWIS, a citizen of the United States',.residing atj;Ypsi-' lanti, county of Washtenaw, State-.ofj -Michigan, have invented a certain new and useful Improvement in Extension, Step, andSca'f fold Ladders; and'I declare, the following tobe a full, clear, andexact description of, the invention, such as will enable others skilled in the art to which it pertains to makef and' use the same, reference being had to the ,ac companying drawings, whichform a part of this specification. l

This invention relates to ladders, and has for its object an improved formof-ladder which may be used as anextensiou-l'adder," step-ladder, or scafiold-ladder.

In the drawings, Figure 1- shows the'ladde'rf spread as a step-ladder or a scaffold ladder. Fig. 2 is a front elevation showing the ladder. as an extension ladder. Fig. 3 is a "front elevation showing the ladder closed in com-' pact form. Fig. 4 is an inside view'of-the; side rail of the larger oneof the two partso'f the ladder. There isalso in Fig. Q a small' cross-sectional view at one of the mortis'es. Fig. 5 is an enlarged detail showing the'oou'pling-irons at the tops of the two parts of the ladder. Fig. '6 is an enlarged detail of the coupling-iron at the upper end'of the inner or smaller one of the two ladders. Fig. 7 is a detail of the holding-dog.

The ladder is made in two parts which are at times separable,- but which in-certain po= sitions of the ladder are so interlocked as to be securely held together until the position is changed, and when spread in' the position shown in Fig. 1 the ladder may be used safely for either a scaifold-ladder or a step-ladder. When the bottoms are brought together, the two parts are still engaged together and can slide longitudinally the one to the other, so that the two parts now become an extensionladder and cannot be disengaged unless one slides entirely out endwise from its engagement with the other. In this condition the extension-ladder is held by dogs which are pinned to the inner ladder and-engage in mor- 1 tises in the outer ladder and which securely hold the extension-ladder in its extended condition. The two dogs are, however, easily and simultaneously disengaged from the mor- I Serial n. 113,481. on; ini.

" tises,'-;and (the. two parts can. then be slid to= getherinto the conditionshown in Fig. 3. v .The outer ladder has two side rails 2 and and eachfoute'r rail is provided with a number ofmortises2fijthe purpose ofjwhich is to hold theends of the dogs hereinafter mentioned. The two side rails 2 and 2 are parallel. The

gether and spaced by-the"rungs4,;and at the the pin ofwhich passes through holes .near

and '5 arelarranged to engage in the. mortises 2. The free-:ends-5 and 5 maybecon sideredas weights that normally tendto drop and throw the engaging ends .into the mortises. .To each of these weight ends issecured a cord 6, that passes upover a sheave .7, which hangs from the upper rung of the larger section of the ladder." The dogs are actuated to disengage them by pulling this cold They automatically engage in the mortises.

, The lower rung 4 of the inner ladder ex tends to 'the outside of each side rail, and the overlapping strip 2 isprovided near its bottom end with notches, through which these projecting ends may pass and the ladder be spread to the form shown in Fig. 1.

In all other positions of the ladder than the one shown in Fig. 3 and the one shown in Fig. 1 the ends of the rung 4* hold the inner ladder from escaping beyondthe side pieces 2, while they permit the two parts to be extended longitudinally.

The junction-irons at the top are shown in Figs. 5 and 6. The iron on the outer or larger section is a plate 8, that extends toward the middle. line of the ladder. The projection 8 lies approximately flush with the front face of the side rail of the ladder. The projection 8 lies about in the line of the rungs and is spaced from the projection 8* the width of the side rail of the inner ladder. Its upper edge is below the lower edge of the projec tion 8 to allow for the desired spread of the lower ends of the two parts of the ladder.-

bottom-of each ,innerrail'is pinned a dog.5 5, Swhichhas-the'form or shape of, a bent lever;

. 2; Each side is provided with an overhang-1 strip" 2 the overhanging edge of which :ex-* .tendstoward'the middle line of the'ljadder,

innerbrl smaller section of the, ladder isalso icomposed'of twoside rails 3 and 3, heldtd the-celbow of the lever. The inn'erends 5 The projection 8 is continued diagonally upward and backward to the back of the plate 8 and there joins the projection 8, which continues in an arched form upward and forward to a point directly over the upper edge of the projection 8 Alug S extends from the plate 8, forming a branch from the diagonal part of the extension 8", and this lug 8 is somewhat below the meeting-line of the diagonal part and the arched part of the extension. The coupling-iron on the innersection of the ladder is a plate 9, provided with a recess 9 near its upper part and opening into it from the back. It is provided also with alug or hook 9 at its front upper edge, and its upper edge is curved to correspond with the arched projection 8. The two coupling-irons thus described interlock, so that the upper edge 9 rests against the curved face 8, with the recess 9 engaging overthe lug 8. The front face of the inner ladder engages against the under side of the projection S. The rear face engages against the oblique extension between 8 and 8, and the parts are securely locked together. They cannot be drawn apart until the bottom ends have been closed together sufficiently to disengage the recess 9 and the lug 8 \Vhen this disengagement has been effected and the lug 9" has come into engagement over the extension 8, the two parts cannot be disen-' gaged by drawing the inner ladder downward. The inner ladder can be pushed upward and the entire ladder extended, and the inner ladder can be drawn out from the outer ladder by pushing it upward or in the direction of extension; but the two parts cannot be disengaged in the other direction. Whenever the ladder is in an upright position and the one part is extended above the other, the holding- dogs 5 and 5 constantly tend, because of their weighted ends, to engage in the notches and to lock the parts. The dogs must be forcibly disengaged by lifting the weighted ends of the lovers either with the cord or in some other way.

What I claim is- 1. A folding and extension ladder, comprising a coupling-iron on the one part provided with parallel guide projections, an arched abutment projection, and a diagonal bearing projection joining the arched projection and one of the guide projections, substantially as described.

2. A folding and extension ladder comprising a coupling-iron on the one part provided with parallel guide projections, an abutment projection lying in a slanting direction with reference to the ladder, a diagonal bearing projection joining the slanting projection and one of the guide projections, and a lug upon one part adapted to extend into a cavity on the other part when the two parts are spread, substantially as described.

In testimony whereof I sign this specification in the presence of two witnesses.

MELVIN .T. LEWIS.

Witnesses:

ZINA RUCK, DARWIN C. GRIFFEN.

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