US3129785A

US3129785A - Collapsible ladder

Info

Publication number: US3129785A
Application number: US257612A
Authority: US
Inventors: Herbert A Keith
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-02-11
Filing date: 1963-02-11
Publication date: 1964-04-21
Anticipated expiration: 1981-04-21

Description

April 21, 1964 H. A. KEITH COLLAPSIBLE LADDER Filed Feb. 11, 1963 INVENTOR United States Patent 3,129,785 COLLAPSIBLE LADDER Herbert A. Keith, 64 Broolrdaie Ave, Toronto, Gntario, Canada Filed Feb. 11, 1963, Ser. No. 257,612 3 tilaims. (Cl. 18224) This invention relates to improvements in collapsible ladders and more particularly to improvements in a collapsible ladder which quickly adapts to suit different applications.

A survey of the prior art reveals numerous structures generally designed to act either as a triangularly formed step ladder or as an extended wall ladder. While certain of these devices achieve their several intended objects with varying degrees of effectiveness, many still leave much to be desired both operationally and from a safety point of view.

It is therefore, a main object of the instant invention to provide a collapsible ladder which may be used as a triangularly formed step ladder or as an extended wall ladder.

It is another object of this invention to provide a collapsible ladder which, upon being used as a tri-angularly formed step ladder, presents a working platform, such a platform being capable of positioning at the apex of the step ladder or at a lower elevation thereon according to requirements.

Still another object of this invention is to provide a collapsible ladder having a bracing section which acts as a rigid stabilizer in the triangular step ladder and, in addition to bracing the ladder in its extended form, acting as a runged section of the complete ladder.

Yet another object of the instant invention seeks to provide a collapsible ladder which is exceptionally safe in use.

A further object of the invention is to provide a collapsible ladder which is light, relatively inexpensive to manufacture, readily portable and rigidly braced during use thereof.

These and various other pertinent objects and features of my invention will become more readily apparent from the following detailed description and when taken in conjunction with the accompanying drawings, in which:

-FIG. 1 is a perspective view of a collapsible ladder embodying this invention mounted in the step ladder attitude and having its Working platform positioned at the apex thereof.

FIG. 1a is a plan view of the underside of the working platforms.

FIG. 2 is a perspective view of a collapsible ladder mounted in a similar attitude to that illustrated in FIG. ,1 but having the work platform in a lower position.

FIG. 3 is a perspective view of a collapsible ladder in its fully extended attitude for use against a wall or the like.

Referring to FIGS. 1 and 2, a collapsible ladder indicated generally by the arrow includes a first section 11 and a second section 12. First section 11 includes two

side rails

11a and 11b held in a parallel spaced apart relationship by a plurality of rungs 11c and elongate rectangular steps 11d, rungs 11c and steps 11d extending perpendicularly therebetween and in parallel spaced apart relationship to each other.

It will readily be understood that steps 11d are included so that a user, having to stand on collapsible ladder 10 for any length of time, may do so with more support and comfort to his feet than would be the case if section 11 comprised the conventional circular sectioned rungs only.

Second section 12 of collapsible ladder 10 includes Patented Apr. 21, 1964 two

side rails

12a and 12b held in a parallel spaced apart relationship by a plurality of rungs 12c, rungs 12c extending perpendicularly therebetween and in parallel spaced apart relationship to each other. A top rung 12d is ofiset from the rest of rungs 12c and has its respective ends housed Within two outwardly projecting sections 13 formed on the edges of

side rails

12a and 12b respectively, and a cross piece 14 of rectangular section is pivotally retained at the top of side rail 12a by a pivot pin -15 at one end thereof, its opposite end being received within a U hook 16 rigidly afiixed at the top of side rail 12b.

Sections

11 and 12 of collapsible ladder 11) are hingedly joined at their upper ends by conventional hinge plates 17, hinge plates 17 being mounted in such a manner as to permit

sections

11 and 12 to be angularly located through 180 degrees.

Referring now to FIGS; 1, la and 2, two

rectangular work platforms

18 and 19 are hingedly attached at adjacent edges by conventional hinge means 18a, platform 18 having its opposite edge pivotally retained upon the uppermost run-g11c of section 11. Platform 19 has two parallel spaced apart lugs "19a rigidly affixed upon its underside and substantially toward its unhinged end;

Lugs 19a, which are adapted to project perpendicularly outwardly from the underside of platform 19, each have a rectangular cut out section 1% formed therein.

Referring now particularly to FIG. ;1

platforms

18 and 19 may be so adjusted to present platform 19 as a horizontally disposed work platform, cut out sections 1% of lugs 1% receiving cross piece 14 and platform 18 acting as a substantially vertical brace.

A third section 20 of collapsible ladder 10 includes two side rails 20a and 2% held in a parallel spaced apart relationship to each other.

Section 20 of collapsible ladder 10 has the upper end of side rails 20a and 20b pivotally retained upon that rung 12c of section 12 immediately below offset rung 12d, side rails 20a and 29b being so spaced apart as to fit within the inner limits of

side rails

12a and 12b and 11a and 11b of collapsible ladder 10, the opposite ends of side rails 20a and 20b terminating in hooked sections 20d and 20:2 respectively, hooks 20d and 20a projecting longitudinally outwardly therefrom.

Still referring to FIG. 1, section 24) of collapsible ladder 10 has its two hooks 20d and 2lle located about the lower rung 11a of section 11 thereby acting as a rigid stay between sections :11 and 12 and preventing the two sections from further outward movement.

Referring now to FIG. 2,

platforms

18 and 19 may be so adjusted as to present platform 18 as a horizontally disposed work platform located substantially two thirds of the way up collapsible ladder 1b in the triangularly formed attitude, the hinged end of platform 18 resting on that rung immediately beneath offset rung 12d, platform 19 being located diagonally between said rung 12c and the rung 12c immediately below.

It will be readily apparent that platform 19 will, in this position, also pass diagonally between two of rungs 200 of third section 20 which is located in longitudinal alignment within section 12, the hooked ends of side rails 20a and 20b being retained by spring loaded dowels 21 similar to the type shown by U.S. Patent No. 2,901,054 at 46, located substantially toward the lower ends of

side rails

12a and 12b and projecting inwardly therefrom.

As section 11 has no further rungs above that rung 11c upon which platform 18 is pivoted, a user may stand or kneel Within

sections

11 and 12 of collapsible ladder 10. Also cross piece 14 may be swung clear if so required.

Referring to FIGS. 2 and 3, upon collapsible ladder 10 having its two

sections

11 and 12 opened outwardly to the full extent, the upper ends of their

respective side rails

11a and 11b and 12a and 12b will abut,

sections

11 and 12 forming one longitudinally disposed ladder for use against a wall or the like. Section has its hooked sections 2ild and 20a of side rails 20a and 2012 respectively affixed on top rung 11c of section 11 thereby providing rungs for the upper portion of section 11 and completing the step sequence of extended collapsible ladder 10.

It will be appreciated that in order to affix hooks 20d and 202 in location about the top rung 200, said hook sections will have to be positioned slightly below the rung, this being achieved with

sections

11 and 12 just short of longitudinal alignment, complete alignment lifting hooks 20d and Zfie into position about the rung.

A small outwardly projecting stop member 22 located at the top of side rail 11a and on its outward edge prevents cross piece 14 from swinging downwardly about pivot pin 15.

Referring to FIGS. 1a and 3, in the extended position of collapsible ladder 10,

platforms

18 and 19 are folded inwardly about hinge 18a, lugs 19a affecting a friction fit upon two retainer dowels 18b, dowels 181) being located within recessed housing 180 of platform 18 and substantially toward the pivotal edge thereof, dowels 18b being frictionally received by cut out sections 1% of lugs 19a thereby allowing platforms l8 and 19 to achieve a face to face contact.

It will readily be seen that platform 18 may if required be detachably hinged to top rung 11c of section 11, thereby allowing for removal upon collapsible ladder 10 being assembled in the extended attitude, this being a matter of individual preference.

The general design of the individual parts of the invention as explained above may be varied according to requirements in regards to manufacture and production thereof, while still remaining within the spirit and principle of the invention, without prejudicing the novelty thereof.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows:

1. A collapsible ladder comprising a first section, a second section, a third section, a first platform member and a second platform member; said first section and said second section being hingedly joined at their upper ends; said first section includes two side rails held in parallel spaced apart relationship by a plurality of rungs and rectangular steps, said rungs and said steps extending transversely therebetween and in parallel spaced apart relationship to each other; said side rails terminating in an upper section having neither rungs nor steps; said second section including two side rails held in parallel spaced apart relationship by a plurality of rungs, said rungs extending transversely therebetween and in parallel spaced apart relationship to each other; a cross piece pivotally retained at one end thereof to the upper end edge of one of said side rails of said second section, the opposite end of said cross piece being located within a U hook, said U hook being rigidly affixed on the upper end edge of the other of said side rails of said second section, said cross piece being parallel with said plurality of rungs; said third section including two side rails held in parallel spaced apart relationship by a plurality of rungs, said rungs extending transversely therebetween and in parellel spaced apart relationship to each other, said third section being substantially shorter than each of said first and second sections; said third section being pivotally retained at the upper ends of its said side rails upon an upper rung of said second section, the lower ends of said side rails terminating in hooked sections, said hooked sections projecting longitudinally outwardly therefrom, said side rails of said third section being so spaced apart as to fit within the inner limits of said side rails of said first and said second sections; said hooked sections of said side rails of said third section being located about said lower rung of said first section said first platform member and said second platform member hingedly joined at adjacent edges; said second platform having at least one lug, said lug being located on the underside thereof and projecting perpendicularly downwardly therefrom, said lug having a cut out section formed therein, said cut out section receiving said cross piece said first platform member having the edge opposite the hinged edge pivotally attached to an upper rung of said first section; said first platform depending angularly downwardly between said second platform and said upper rung of said first section; and said second platform being horizontally disposed.

2. A collapsible ladder as defined in claim 1 in which said first and said second sections form one longitudinally disposed ladder, their said hinged upper ends abutting, said third section extending longitudinally between said upper rung of said second section and said upper rung of said first section, said hooked sections of said third ladder section engaging with said upper rung of said first section; and said third section thereby providing rungs for said upper portion of said first section and completing the step sequence.

3. A collapsible ladder as defined in claim 1 in which said first platform is horizontally disposed between said first and said second ladder sections, said first platform extending from said upper rung of said first section to said upper rung of said second section, said platform resting on said upper rung of said second section, said second platform depending angularly downwardly between said upper rung of said second section and the rung immediately below, thereby acting as a brace and maintaining said first and said second ladder sections at a predetermined angle; said third ladder section lying in longitudinal alignment within said second section; and two spring loaded dowels, located substantially toward the lower ends of said side rails of said second section and projecting inwardly therefrom, said dowels retaining said hooked sections of said third ladder section thereby maintaining said section in longitudinal alignment within said second section.

References Cited in the file of this patent

Claims

1. A COLLAPSIBLE LADDER COMPRISING A FIRST SECTION, A SECOND SECTION, A THIRD SECTION, A FIRST PLATFORM MEMBER AND A SECOND PLATFORM MEMBER; SAID FIRST SECTION AND SAID SECOND SECTION BEING HINGEDLY JOINED AT THEIR UPPER ENDS; SAID FIRST SECTION INCLUDES TWO SIDE RAILS HELD IN PARALLEL SPACED APART RELATIONSHIP BY A PLURALITY OF RUNGS AND RECTANGULAR STEPS, SAID RUNGS AND SAID STEPS EXTENDING TRANSVERSELY THEREBETWEEN AND IN PARALLEL SPACED APART RELATIONSHIP TO EACH OTHER; SAID SIDE RAILS TERMINATING IN AN UPPER SECTION HAVING NEITHER RUNGS NOR STEPS; SAID SECOND SECTION INCLUDING TWO SIDE RAILS HELD IN PARALLEL SPACED APART RELATIONSHIP BY A PLURALITY OF RUNGS, SAID RUNGS EXTENDING TRANSVERSELY THEREBETWEEN AND IN PARALLEL SPACED APART RELATIONSHIP TO EACH OTHER; A CROSS PIECE PIVOTALLY RETAINED AT ONE END THEREOF TO THE UPPER END EDGE OF ONE OF SAID SIDE RAILS OF SAID SECOND SECTION, THE OPPOSITE END OF SAID CROSS PIECE BEING LOCATED WITHIN A U HOOK, SAID U HOOK BEING RIGIDLY AFFIXED ON THE UPPER END EDGE OF THE OTHER OF SAID SIDE RAILS OFF SAID SECOND SECTION, SAID CROSS PIECE BEING PARALLEL WITH SAID PLURALITY OF RUNGS; SAID THIRD SECTION INCLUDING TWO SIDE RAILS HELD IN PARALLEL SPACED APART RELATIONSHIP BY A PLURALITY OF RUNGS, SAID RUNGS EXTENDING TRANSVERSELY THEREBETWEEN AND IN PARELLEL SPACED APART RELATIONSHIP TO EACH OTHER, SAID THIRD SECTION BEING SUBSTANTIALLY SHORTER THAN EACH OF SAID FIRST AND SECOND SECTIONS; SAID THIRD SECTION BEING PIVOTALLY RETAINED AT THE UPPER ENDS OF ITS SAID SIDE RAILS UPON AN UPPER RUNG OF SAID SECOND SECTION, THE LOWER ENDS OF SAID SIDE RAILS TERMINATING IN HOOKED SECTIONS, SAID HOOKED SECTIONS PROJECTING LONGITUDINALLY OUTWARDLY THEREFROM, SAID SIDE RAILS