US2636659A

US2636659A - Extension ladder

Info

Publication number: US2636659A
Application number: US87716A
Authority: US
Inventors: Raymond R Salisbury
Original assignee: HELEN SALISBURY NIXON
Current assignee: HELEN SALISBURY NIXON
Priority date: 1949-04-15
Filing date: 1949-04-15
Publication date: 1953-04-28
Anticipated expiration: 1970-04-28

Description

Apnl 28, 1953 R. R. SALISBURY 2,636,659

EXTENSION LADDER Filed April 15, 1949 2 SHEETS-SHEET 1 AZ INVENTORQ 25' M 4 '7 1 7.7: ZRgR5aZi$$zry Patented Apr. 28, 1953 EXTENSION LADDER Raymond R. Salisbury, Ann Arbor, Mich., as signor of one-half to Helen Salisbury Nixon,

Ann Arbor, Mich.

Application April 15, 1949, Serial No. 87,716

1 Claim.

lihis invention relates toladders.

An object of this invention is to provide an improved extensible ladder construction wherein the side rails of the ladder are formed of channel members with the rails of one ladder section oppositely disposed with respect to the rails of the other ladder section, and with an improved. locking means for locking the ladder sections together.

Another object of this invention is to provide an extensible ladder formed of channelled rails and channelled rungs, with the rungs substantially narrower than the rails so as to provide a guide space within which one flange of another ladder section is adapted to slidably engage.

A further object of this invention is to provide a. ladderstructure which can be easily and quickly formed into an inverted V-shaped support for a platform, and where two pairs of ladder sections are coupled together the platform may be disposed at any selected height.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claim.

In the drawings,

Figure 1 is a detail side elevation of an extensible ladder constructed according to an embodiment of this invention,

Figure 2 is a sectional view taken on the line 2-2 of Figure 1,

Figure 3 is a sectional view taken on the line 3-3 of Figure 1,

Figure 4 is a fragmentary sectional view taken on the line 4-4 of Figure 3,

Figure 5 is a fragmentary sectional view taken on the line 5-5 of Figure 6,

Figure 6 is a fragmentary sectional view taken on the line S6 of Figure 5,

Figure 7 is a fragmentary sectional view taken on the line 11 of Figure 1,

Figure 8 is a fragmentary sectional view taken on the line B-8 of Figure 2,

Figure 9 is a detail front elevation, partly broken away, of the ladder with a pair of sections detachably connected together.

Referring to the drawings, the numeral [0 designates generally an elongated ladder section and the numerals II and i2 designate generally a pair of ladder sections which are adjustably connected together. In the present instance the ladder sections are connected together to form a step ladder with the two adjustable sections H and I2 forming the legs of the ladder section [0.

The ladder section It is formed of a pair of The rungs or steps [9 are formed of channel members and these channel members at each end have extending upwardly therefrom end flanges 20 which are adapted to be secured by fastening means 2 I to the inner side of the rails ii and I8. 'lhe channel members l9 forming the rungs or steps are substantially narrower than the distance between the flanges of the channel members I1 and it! so as to thereby form spaces 22 at each side of the rungs or steps I9 so that the channel-shaped rails 23 and 2c of the ladder section 12 may SllQing'ly engage in the spaces 22 and between the rungs or steps l9 and the ad acent flanges of the inwardly facing channel members.

lne

channel members

25 and 24 face outwardly and the rungs or steps 25 which are secured to the inner sides of the

channel members

23 and 24 are provided at each end thereof with flanges 26 secured by fastening means 21 to the web 26 of the

side rails

23 or 24.

in order to provide a means whereby the ladder sections II and 12 may be adiustably locked together with the ladder section II adjusted endwise or the ladder section H, I have provided a pair of pivoted pawls 29 which are secured in the channels of the

rails

23 and 24 adjacent one end thereof. The pawl 29 is pivotally mounted on a pivot 30 extending through a U-shaped. housing 3!, and the pawl 29 includes a bill 32 which is adapted to engage through a keeper opening 33 formed in the nange 34 of the ladder section H or 18.

The flange 35 of the

rail

23 or 24 is also formed with a keeper opening 36 adapted to register with a keeper opening The pawl or looking member 29 includes an elongated handle or lever 31 which is adapted to be yieldably held in either latched or released position by means of a bowed spring 38.

l'he ladder section II is adapted to be secured at its upper end to the ladder section It by means of a bolt or rod 39 which is carried by a paineof supporting lugs 40 which are secured to the chan-i nel members 14 and [5. The upper ends of the rails I1 and I8 are formed with upwardlyopcn- 3 ing slots M through which the rod 39 is adapted to loosely engage, and the rod 39 is firmly secured in the slots 4| by means of a nut 42 which is threaded onto the rod 39.

The ladder sections when used as a step ladder, as shown in Figure 1 are held against spreading relative to each other by means of a chain 43 which is connected at one end to an eye 44 carried by the ladder section I I and is formed with a hook 45 engaging through a step or rung 16 of ladder section 10.

Where it is desired to form an extensible ladder the two ladder sections H and [2 are used and may be adjustably secured together by the pawls or dogs 29. Where the ladder sections" H and I2 are used as an extensible ladder, as shown in Figure 9, they are separated from the ladder section 19. The rails of the ladder section which engage a floor or other surface may have rubber feet 49 mounted thereon so as to prevent scratching cf the floor or slipping onthe floor.

This ladder structure is adapted to be made out of relatively lightweight metal and will provide an improved ladder structure which will permit the formation of either a step ladder or an extensible ladder from the three ladder sections herein disclosed.

I do not mean to confine myself tothe exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claim.

What I claim is:

An extensible ladder comprising a pair of ladder sections, each section being formed of channel shaped rails, rungs fixed between said rails, the channels of one section being oppositely dis, posed with respect to the channels of the other section, said rungs carried by said one section being narrower than the distance between the flanges of the rails thereof whereby to provide guide spaces between the mugs and flanges, the

channels of the other of said sections facing outwardly whereby the flanges of the rails of said other section may slidingly engage in said spaces, and means comprising aligned apertures in the adjacent flanges of'one channel shaped rail of each of said pair of sections and a locking dog, V- shaped bracket in the upper end of the other of said channels, a pivot mounting said dog for swingabl e movement in said bracket, said dog having an operating lever extending above the top of said other channel, said dog also having aprojection including a flat upper surface and an inclined lower surface engageable through said apertures carried by one of said sections for locking said sections together in endwise adjusted position, said flat upper surface locking said sections against movement toward each other, and said inclined surface acting as a pawl to permit extension of said sections relative to each other .1 l.

RAYMOND a, SALISBURY.

References Cited in the file of this patent UNITED STATES PATENTS 593,874 Great Britain .11. Oct.- 28, 1947