US3878918A

US3878918A - Adjustable ladder

Info

Publication number: US3878918A
Application number: US387730A
Authority: US
Inventors: Anthony G Basile
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-08-13
Filing date: 1973-08-13
Publication date: 1975-04-22
Anticipated expiration: 1992-04-22

Abstract

A ladder having adjustable extensions secured to the lower ends of the ladder legs so that the ladder can seat upon an inclined surface or steps on different elevations; each extension having a row of openings slong its length, a selective one of the openings being engaged by a transverse bolt extending through the ladder leg.

Description

United States Patent Basile Apr. 22, 1975 1 ADJUSTABLE LADDER l.()l6.l77 1/1912 Rogers l82/200 1.246. ll B .1 I8 204 [76] Inventor: Amhmy Bague- Georg? 2.115.322 1821204 Specmr 36l5 Woolworth Bulldmg 3.051431 10/1962 George l82/l63 233 Broadway, Brooklyn, NY.

PHIHGI') b.\'am1ner-Remaldo P. Machado [22] Filed: Aug. 13, 1973 [2]] Appl. No.: 387.730 [57 ABSTRACT A ladder having adjustable extensions secured to the [52] US. Cl. 182/202 hwer ends of the l d legs so that he ladder can [51] llll. Cl. E06c 7/44 Seat upon an inclined Surface Steps on diffsrem ele' [58] held of Search 182/200, 204, 202; vafions; each extension having a row of openings Slong 248/1882 188-3 its length, a selective one of the openings being engaged by a transverse bolt extending through the lad- [56] References Cited der UNITED STATES PATENTS 934.540 9/1909 Kovacs 248/1882 2 Claims 3 D'awmg F'gum ADJUSTABLE LADDER This invention relates generally to ladders. More specifically it relates to ladder accessories.

A principle object of the present invention is to provide a pair of extensions which are adjustably secured to the lower end of a ladder so that the ladder can stand upright upon an uneven or inclined ground, or which can rest with each leg on a different step of a staircase.

Another object is to provide an adjustable ladder wherein the extensions can be extended on either a right or left leg of the ladder.

Yet another object is to provide an adjustable ladder which may comprise either a step ladder with extensions or either or both legs. or which may comprise a safety ladder with the extensions mounted on both front or both rear legs, so that the front legs are on rested upon a different step than the rear legs so the safety ladder can face the steps.

Other objects are to provide adjustable ladder which is simple in design, inexpensive to manufacture, rugged in construction, easy to use and efficient in operation.

These and other objects will be readily apparent upon a study of the following specification and the accompanying drawings wherein;

FIG. 1 is a perspective view of one form of the invention wherein separate removal extensions are adjustably attached to a ladder.

FIG. 2 is a fragmentary front view of a modified design of the invention.

FIG. 3 is a cross sectional view taken on line 33 of FIG. 2.

Referring now to the drawing in detail, and more particularly to FIG. 1 at this time, the reference numeral I represents an adjustable ladder according to the present invention wherein there is a step ladder ll which has an adjustable extension I2 attached to a lower end of each leg 13.

Each extension 12 is shown to consist of a sleeve made by formed metal plate, the sleeve accordingly having an open slot 14 that extends the length thereof. The sleeve has a central opening 15 into which the leg [3 is receivable. and the slot 14 forms a clearance for allowing the sleeve to slide upwardly past the lowermost rungs 16 of the ladder. The extension has a row of openings along its length for selectively receiving a bolt 17 mounted transversely through the leg, and which is secured by a wing nut 18. Thus a person can adjust the ladder so it can stand on any uneven ground or on different steps 19 of a staircase.

Alternately instead of being made of metal, the extensions may be made of channeled wood blocks so to include the above features.

While the drawing shows the extensions applied to a step ladder, the invention is suitable also to a safety ladder front or rear legs so the ladder can face the steps of a staircase.

In FIGS. 2 and 3 ofthe drawing, a modified design of improved adjustable ladder 20 is shown in which extensions 21 on each leg 22 of the ladder is integral with a toothed rack 23; the racks toothingly engaging a rotatable gear 24 therebetween. The gear has a square central opening so to be slidable along a square shaft 25, the shaft being integral with a knob 26 which is rotatable so to rotate the shaft and gear. A stationary panel 27 is secured between ladder legs 22, and a clearance opening through the center of the panel freely receives the shaft to rotate therein. The knob is on one side of the panel. and the gear is on the opposite side thereof. It is now evident that when the knob is turned, one extension 21 slides downward while the other ex tension slides upward, so they can be adjusted to standing on a stairway or on an inclined ground.

In order to stationarily secure an adjusted position of the extensions. the knob 26 is rendered non-rotatable by having a pair of projections 28 on its rear which are selectively engagable in openings 29 of the panel 27. In order to allow rotation of the knob, (when adjustment of the extensions is desired), the knob can be forwardly pulled against the action of a compression coil spring 30 around the shaft 25 and which is located between the gear 24 and an enlarged head 31 on a rear end of the shaft. When the knob is released after adjustment the spring causes the projections 28 to hold in the openings 29, thus insuring the device to be safely locked against slipping. No bolts 18 are needed.

Thus a modified design has been provided wherein extension adjustment is simply accomplished by pulling out the knob and then let it push itself back automatically in a proper opening while the ladder is being adjusted to best upright standing position.

While various changes may be made in the detail construction. it is understood that such changes will be within the spirit and scope of the present invention.

1 claim as follows:

1. A ladder having lower spaced legs mounted adjustably on the lower end of said ladder for longitudinal movement relative to each other and said ladder whereby said legs can be positioned at different longitudinal positions relative to the lower end of said ladder. in combination with a rotary gear rotatably mounted at the lower end of the ladder between said legs. including teeth extending from each leg to engage said gear whereby rotation of said gear causes relative longitudinal motion of the legs, including means for selectively locking the gear to the ladder thereby preventing rotary motion and movement of the legs when posi tioned at desired locations wherein the lower end of the ladder includes parallel rails and said legs are mounted on rails members for parallel relative extending motion thereto. including a fixed panel transversely connected to said rails. said gear having a shaft rotatable mounted transversely on said panel. said gear being spaced from and parallel to said panel. said shaft being mounted axially slidable relative to both panel and gear, said means comprising coacting portions on said shaft and panel which interlock when the said shaft is slid axially to predetermined first position and wherein said portions are free of each other when the shaft is moved to a second position permitting rotation of the gear.

2. A ladder as in claim I, wherein said means further includes a knob on said shaft for moving the shaft axially and prongs extending from said knob. said panel having holes to receive said prongs further including a spring normally biasing the shaft to the first position whereby the prongs are received in the holes thereby locking the shaft and the gear against rotary motion. said shaft being axially movable to said second position wherein the prongs are received in the holes thereby locking the shaft and the gear against rotary motion. said shaft being axially movable to said second position wherein the prongs are clear of the holes whereby the shaft and gear can be rotated to effect relative motion of the legs.

Claims

1. A ladder having lower spaced legs mounted adjustably on the lower end of said ladder for longitudinal movement relative to each other and said ladder whereby said legs can be positioned at different longitudinal positions relative to the lower end of said ladder, in combination with a rotary gear rotatably mounted at the lower end of the ladder between said legs, including teeth extending from each leg to engage said gear whereby rotation of said gear causes relative longitudinal motion of the legs, including means for selectively locking the gear to the ladder thereby preventing rotary motion and movement of the legs when positioned at desired locations wherein the lower end of the ladder includes parallel rails and said legs are mounted on rails members for parallel relative extending motion thereto, including a fixed panel transversely connected to said rails, said gear having a shaft rotatable mounted transversely on said panel, said gear being spaced from and parallel to said panel, said shaft being mounted axially slidable relative to both panel and gear, said means comprising coacting portions on said shaft and panel which interlock when the said shaft is slid axially to predetermined first position and wherein said portions are free of each other when the shaft is moved to a second position permitting rotation of the gear.