US2559992A

US2559992A - Extension ladder

Info

Publication number: US2559992A
Application number: US665177A
Authority: US
Inventors: Jr John L Painter
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-04-26
Filing date: 1946-04-26
Publication date: 1951-07-10
Anticipated expiration: 1968-07-10

Description

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July 10, 1951 Flled Aprll 26 1946 July 10, 1951 J. 1.. PAINTER, JR 2,559,992

EXTENSION LADDER Filed April 26, 1946 2 Sheets-Sheet 2 I I! new tar .2 John Z. Pa'z'rzz egdiz' a5 By Patented July 10, 1951 UNITED STATES PATENT OFFICE 2,559,992 EXTENSION LADDER John L. Painter, Jr., West Newton, Pa.

Application April 26, 1946, Serial No. 665,177

My invention relates to improvements in extension ladders, the primary object in view being to provide an extension ladder of all metal construction, to conserve wood, and which is light in weight, yet strong, inexpensive to manufacture, and equipped with easily operative pull means for extending the ladder adapted for locking the same extended or contracted when relieved of pull thereon.

Other and subordinate objects, also comprehended by my invention, together with the precise nature of my improvements and the manifold advantages thereof will be readily understood when the succeeding description and claims are read with reference to the drawings accompanying and forming part of this specification.

In said drawings:

Figure 1 is a view in front elevation of my improved extension ladder, in a preferred embodiment thereof, showing the same extended,

Figure 2 is a view in side elevation, partly broken away,

Figure 3 is a fragmentary view in perspective of the extension section,

Figure 4 is a fragmentary view in longitudinal section taken on the line 44 of Figure 1,

Figure 5 is a view in longitudinal section taken on the line 5-5 of Figure 2 and drawn to an en larged scale,

Figure 6 is a fragmentary view in perspective of the main or base section,

Figure '7 is a fragmentary view in horizontal section taken on the line 'I'I of Figure 5, and

Figure 8 is a fragmentary view in vertical section taken on the line 8-8 of Figure 5.

Reference being had to the drawings by numerals, my improved extension ladder, as shown, comprises a main, or base, section I including laterally spaced, parallel, side members 2 of channel iron form, and any suitable light strong metal. The side members 2 on the confronting, or inner side faces thereof are formed with front and rear right

angled edge flanges

3, 4 confronting to form therebetween longitudinal slots 5 in the inner side faces of the members extending centrally thereof from end to end of the same. The side members 2 function as guides for an extension section 6, to be described.

Rungs I of T-iron form are welded, or otherwise secured. as at 8, at their ends'zto the rear flanges 4, and are spaced apart vertically with the usual spacing therebetween and with flat sides uppermost so that said rungs are of step-like form. As will be seen, the rungs I are arranged in the rear of the longitudinal center of the main 2 Claims. (01. 228-65) section 2 and in the rear of the slots 5. The purpose of this arrangement will presently be" clear. As best shown in Figure 8, the rungs I are arranged so that the uppermost fiat sides thereof incline toward the front of the mainsection I so that when said section is inclined upwardly and rearwardly, the uppermost flat sides of the rungs will be positioned substantially horizontally to provide approximately level steps, with the main section I arranged at the necessary inclination.

The extension section 6 includes side members 9 vertically slidable in the side members 2 of the base section I and constructed in the same manner as said members 2 with the exception that the outer side faces of said members 9 are formed with the longitudinal central slots I0 corresponding to the slots 5 of said members 2. The rungs II of the extension section 6 are constructed and arranged in the same manner as the rungs I of the main section I with the exception that said rungs I I are secured to'the side members 9 in the longitudinal centers of said members so that said rungs I I may pass into and out of the slots 5 in the side members 2, and slightly for-' wardly of the rungs 1.

For sliding the extension section 6 outwardly and inwardly relative to the base section I to extend and contract the ladder, respectively, the following meansis provided.

A pull line, preferably in the form of a flat tape I2 is extended slidably through a ring I3 swivellcd, as at I4 on the top rung I of the base section I in the transverse center of said rung and so that said tape provides a pendent free handgrip portion I5 and an attaching end I6 both, preferably, in front of the rungs I and II. The attaching end I6 is secured, as at H, to the center portion of a flexible wire pull member I8 slidably extended upon opposite sides of its center downwardly through a tubular guide I9 of inverted V-shape suitably secured by a flange 20 to a rung II of the extension section .6 in the transverse center of said section. From the guide I9, the member I8 inclines downwardly to a pair of tubular upwardly curved guides 2| suitably fixed on top of the rung I I immediately below the rung I I to which said guide I9 is fixed, said guides 2I being arranged to extend into the slots 5 of the side member 2 at opposite ends of the rung II on which the same are fixed. At the terminals thereof, said member I8 is suitably attached, as represented,'for instance, at 22 to the inner ends of a pair of latch bolts 23 slidably extended through the inner side faces of the side members 9 and spring loaded, as at 24 to be projected outwardly into vertically spaced apertures 25 provided in the outer side faces of the side members 2 of the base section I. Collars 26 on the latch bolts 23 slidably fitted in suitable guide bushings 21 on the side members 9 guide said latch bolts in projection and retraction thereof and by engagement with the outer side faces of the side members 2 limit projectin movement of said latch bolts. The bushings 21, as will be un'-' derstood, are arranged to play vertically in the slots of the side member 2. The apertures 25 are vertically spaced in correspondence with the spacing of the rungs l, and H but slightly above rungs .1 of the base section I so that when the said means comprising a pair of opposite bushlatch bolts 23 enter said apertures 25, the rungs" ll of the extension section 6 which are positioned between the side members 2 of the base section I will be slightly higher than the rungs I of said base section. This is to provide for spacing the instep portion of the feet on top of such rungs l i without interference by the adjacent rungs l. v

I'he manner in which the described ladder is extended and contracted will be readily understood. By pulling on the hand-grip portion 15 of the tape l2, with the ladder in proper position, a pull may be exerted on the member Hi to retract the latch bolts 23, in opposition to the springs 24:, out of apertures 25 into which the may have been projected. Thus the extension section 6 is unlocked, or unlatched, from the main section i for sliding inwardly Or outwardly of said main section. By continuin the pull on the hand-grip section IS, the latch bolts 23 will be st pped. in fully retracted positions as the collars 26 fully compress the springs 24, at which point, the extension section 9 will be pulled outwardly of the base section I. When the extension section 9 has been extended to the desired position, the. handgrip portion l5 of the tape 12 may be released and theextension section held by hand until the latch bolts 23 are projected by the springs 24. into the appropriate apertures 25 to lock the extension section 9 in selected extended position. By easing upon the pull on the hand-grip portion l5 of the tape I2 sufliciently to permit the xtension section 9 to move inwardly of the base section i- (under the influence of gravity), the ladder may be contracted to a desired extent and the extension section 6 locked, or latched, to the main section I in the same manner as describedwith ings fixed in the channels of the inner side members in hidden position, spring loaded latch bolts slidably retractile in said bushings and extending out of. said bottoms, a pair of upwardly curved tubular guides on one rung opposite said latch bolts, a flexible pull member of inverted V-shape REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 229,472 Rood June 29, 1880 356,088 Barnes Jan. 18, 1887 428,995 Adley May 27, 1890 657,982 Gardner Sept. 18, 1900 675,744 Lewis June 4, 1901 873,110 Williamson Dec. 10, 1907 194 1 382 Wecker Jan. 23, 1934 2,016,196 Handfield Oct, 1, 1935 2,186,181 Steinlein Jan. 9, 1940 2,298,367 Nelson Sept. 22, 1942 2,542,398 Crumpton Feb. 20, 1951 FOREIGN PATENTS Number Country Date 8,599 Great Britain 1840 7 144,733 Germany Sept. 26, 1903