US3208553A

US3208553A - Folding ladder

Info

Publication number: US3208553A
Application number: US316246A
Authority: US
Inventors: Gray Lanier
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-10-15
Filing date: 1963-10-15
Publication date: 1965-09-28
Anticipated expiration: 1982-09-28

Description

S e'pt. 28,1965 L. GRAY FOLDING LADDER 2 Sheets-Sheet 1 Filed 001;. 15, 1963 L. GRAY FOLDING LADDER I Sept 28, 1965 2 Sheets-Sheet 2 Filed Oct. 15, 1963 INVENTOR GRAY ATTORNEY United States Patent 3,208,553 FOLDING LADDER Lanier Gray, 214 N. Pitt St., Alexandria, Va. Filed Oct. 15, 1963, Ser. No. 316,246 11 Claims. (Cl. 182-24) The present invention relates to an improved ladder, and more particularly to a light weight, tubular ladder which is foldable to occupy a minimum of space for storage and unfoldable to provide either an extension or step ladder, the construction being such that the ladder is also divisible into individual step ladders usable as supports for a platform.

It is an important object of the invention to provide a light weight, sectionalized, step ladder foldable into a compact package for storage and wherein the sections are hinged together and when folded lie contiguously one over another.

Another object of the invention is to provide a ladder, of the above described characteristics, which may be quickly and readily unfolded and the sections aligned to form an extension ladder.

A further object of the invention is to provide an improved ladder, of the above described characteristics, which may be unfolded to form a step ladder in which adjacent sections are locked together at an acute angle.

It is still another object of the invention to provide a ladder, of the above described characteristics, wherein is additionally provided a separable extension section which may be readily assembled, to the remaining sections, or as readily disassembled therefrom.

Yet another object of the invention is to provide an improved ladder, of the above described characteristics, wherein the individual sections comprise stiles having tubular cross sections formed of a lightweight material so as to provide sturdiness as well as lightness, the reduced weight permitting ready folding and unfolding manipulations by one person.

A still further object of the invention is to provide an improved ladder, having the above described characteristics, wherein tubular lock means is provided within at least some of the sections, said means being easily slideable longitudinally into telescopic engagement with an adjacent section for locking said sections together, the tubular construction of the lock means being such as to provide a rigid and sturdy connection between sections when unfolded and locked together.

Yet a further object of the invention is to provide an improved ladder, having the above described characteristics, wherein hinges are provided between adjacent sections, each hinge having resilient, releasable latch means for locking adjacent sections together at a preselected angle.

Still another object of the invention is to provide an improved ladder, having the above described characteristics, which is of simple construction, easy and economical to fabricate, and easy to fold and unfold.

The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein like reference characters indicate like parts throughout the several figures and in which:

FIG. 1 is a side elevation of a ladder according to the invention which has been unfolded to form a step ladder;

FIG. 2 is an end elevation of the step ladder of FIG. 1;

FIG. 3 is a side elevation of the same ladder unfolded to form an extension ladder;

FIG. 4 is an enlarged, perspective view of portions of two adjacent ladder sections, partially broken away to reveal inner details, and indicating by arrow the mode of unfolding said sections;

FIG. 5 is a perspective view similar to FIG. 4 but showing the sections turned into alignment and locked together;

FIG. 6 is a fragmentary, enlarged, vertical sectional view of the upper end of the step ladder of FIG. 1, with the upper support exploded to a position ready for assembly with the unfolded and angled, upper sections;

FIG. 7 is an enlarged section taken on line 7- 7 of FIG. 1 and looking in the direction of the arrows;

FIG. 8 is an elevation showing the ladder folded for storage;

FIG. 9 is an elevation showing the ladder separated into two short step ladders for support of a platform;

FIG. 10 is a fragmentary, enlarged, sectional elevation of portions of the ladder sections as shown in FIG. 9, illustrating the bracing pivot arms which hold the sections at an angle to each other, and

FIG. 11 is a side elevation of an extension for the ladder of FIG. 3 assembled to a fragment of the upper section.

Referring now more particularly to the drawings, the foldable, combined extension and step ladder may be composed of two or more sections and preferably comprises at least four

separate sections

10, 12, 14 and 16, respectively. These four sections, as shown in FIGS. 1 and 2 have laterally spaced side bars, or stiles 18, and vertically spaced transverse connecting rungs 20. The stiles 18 are preferably formed as hollow tubes of rectangular cross section and the rungs 20 as cylindrical tubes welded, or otherwise secured at their ends, to the stiles, however, these elements may obviously have other cross-sectional shapes. Both the upper and lower ends of all stiles 18 are preferably rounded as shown at 22. The completed sections and their components are desirably identical in dimensions, having the same overall widths and lengths. For lightness, the described elements may be formed of a lightweight metal such as magnesium, or aluminum. If desired they may be formed of a sturdy plastic or other suitable material.

Connecting adjacent ones of

sections

10, 12, 14 and 16, preferably at both side faces of each stile, are the hinges generally indicated by the reference numeral 24. Each hinge, as best shown in FIGS. 4, 5 and 7, comprises a metal strap 26 having openings at its

opposite ends

28 and 30 in which are respectively received the

pivot studs

32 and 34. Pivot 32 may be formed as a rivet having heads on each end, one of which is soldered, or welded, to the associated stile and countersunk so that it is flush with the inner surface thereof. The outer head overlies the wall of opening 28 and retains the strap 26 pivotally secured to the stile. The pivot stud 34 desirably is headed only at its inner end, and countersunk in and secured to its associated stile. The outer head is preferably omitted so that strap 26 may be removed from stud 34 by pulling the end of the strap outwardly. An opening is formed through pivot stud 34 to receive a cotter pin 37, or other suitable fastening element as shown in FIG. 7. The

pivot studs

32 and 34 are positioned on both outer and inner faces of opposed side walls of adjacent stiles and at the centers of their curved ends 22 so that the hinge means 24 permits the adjacent sections to turn through an angle of 360 with the curved edges 22 in rolling contact. Such turning enables the adjacent sections of the ladder to be folded so as to lie contiguously, one over the other, as shown in FIG. 8, or to be unfolded in the manner indicated by arrow A of FIG. 4 so that the adjacent sections form an acute angle as illustrated in FIG. 1, or to be unfolded into alignment as illustrated in FIGS. 3 and 5.

Referring again to FIGS. 4 and 7 at least the outer hinges 24 are provided with a resilient latch formed by a spring metal strap 36, secured near one end by rivet 38 to the strap 26, and having its other end 40 outwardly bent and curled. A pin 42 is fixed to the strap near end 40 and passes inwardly through aligned

openings

44 and 46 in the strap 26 and stile 18 respectively. Opening 46, as best shown in FIG. 4 is positioned in the stile so that when the adjacent sections are turned to form an acute angle, as shown in FIG. 1, the hinge strap 26 will overlie opening 46, and the opening 44 in strap 26 will align therewith to permit entrance through both openings of pin 42. When thus positioned, the pin 42 prevents angular movements, separation or closing, of the

sections

12 and 14 until the latch end 40 is lifted away from the strap 26 to remove the pin 42 from the opening 46.

Sections

12 and 14 are each provided with a tubular locking member 50 for locking said sections to

sections

10 and 16 respectively. Section 12 is provided with a similar, second locking member 50 for locking section 12 to section 14 when the ladder is unfolded to form an extension ladder. Each locking member 50 is preferably formed of the same lightweight metal as the stile of the ladder and has a similar cross-sectional shape, but slightly smaller, so as to telescope within the stile from a fully inward position to a position protruding out of the stile and into the adjacent stile. This action is best illustrated in FIGS. 4 and 5, wherein FIG. 4 shows the locking member 50 fully seated within section 12, whereas in FIG. the locking member has been slid longitudinally to protrude into section 14 firmly securing the

sections

12 and 14 together as if they were one piece. For movement and locking of member 50, a stud 52 is provided, said stud having enlarged inner and outer ends 54 and 56 and being slideable in a transverse slot 58 in member 50. The heads 54 and 56 form shoulders which retain the stud, or latching detent 52, assembled to member 50 and the stile 18. A longitudinal slot 60 is formed in the stile 18 of the associated section to receive the stud 52 when it is positioned toward one end of the slot 58. Thus the head 56 may be grasped in the fingers and pulled along slot 60 to move member 50 longitudinally into the adjacent stile. Slot 60 communicates at one end with a transverse slot 62 having opposed longitudinal notches 64. Thus the stud 52 is movable longitudinally along slot 60, transversely into slot 62, and longitudinally into one of the notches 64, thereby locking the stud 52 with the connected lock member 50 in its locking position protruding into the adjacent ladder section.

It will be noted that in certain positions of the ladder sections the locking members 50 are retained in their locking positions by force of gravity without the need for the transverse slots 62 and

notches

62, 64. However, in other positions of the sections, as for example when the

sections

14 and 16 are turned upwardly as in FIG. 3, the locking members must be moved upwardly into locking positions and the transverse slot 62, therefor, is necessary to provide detents which will ensure that the sections will not become unlocked by gravity.

Assuming that the ladder is folded in compact form as shown in FIG. 8, for storage or transportation, and that it is desired to unfold the device to form an extension ladder, such as is shown in FIG. 3, it is then only necessary to turn the sections with respect to each other in the direction of arrow A, FIG. 4 until adjacent sections are aligned as in FIG. 5. The locking members 50 are then moved longitudinally by grasping and moving the heads 56 of the detents 52 first along the slots 60, and then transversely to move the detents 52 into the slots 62. Finally the detents are locked by another longitudinal movement into one of the notches 64. When this has been done, adjacent sections are firmly locked to one another, without danger of accidentally unlocking.

If a longer extension ladder is required, any additional number of sections may be provided, as for

example sections

66 and 68 similar to

sections

10, 12, 14 and 16 and having hinge means 24 and a locking element 50, see FIG. 11. Desirably one of the extension sections, see 66, may include a fixed locking tube 70 soldered, welded or otherwise firmly secured within and protruding from the lower. end thereof. The protruding end of tube 70 may be pushed into the open, upper end of section 16 when the ladder of FIG. 3 is to be extended. If desired, the tubes 70 may be integrally formed as reduced portions of the corresponding stiles of section 66.

Should it be desired to form a large step ladder, the folded device of FIG. 8 may be unfolded so that

sections

10 and 14 are respectively locked in alignment with

sections

12 and 16, and

sections

12 and 14 are at an angle to each other as shown in FIGS. 1 and 2. The

sections

12 and 14 are fixedly retained in this angle by the pin 42 on the latching bars 36 falling into opening 46 of the section 14 as previously explained. The sides of the step ladder thus formed are thus firmly locked by the upper hinge assemblies 24 and are thus prevented from spreading under the weight of the user.

Additional means are provided to assist in holding the sides of the step ladder at the desired angle. One such means includes a shelf 72 having support arms 74 extended parallel to the shelf, each such support arm being spaced to fit between a pair of stiles 18. Each arm 74 is provided with an inverted, U-shaped spring clip 76 whose downwardly directed, open end spreads and contracts to admit and grasp the top of a lower rung of section 12. Another spring clip 78, also of U-shape but opening upwardly, has one of its legs secured to the end of arm 74. Clip 78 admits and clamps the same rung of section 14. It is apparent that, when both spring clips 76 and 78 of each arm 74 are thus engaged about the rungs of the angled ladder sections, the shelf will be firmly secured to the ladder and the ladder sections will be held from spreading or contracting. When it is desired to fold the step ladder, the shelf 72, is merely lifted counterclockwise, as seen in FIG. 6, to release

clips

76 and 78 from the ladder rungs.

A somewhat similarly constructed top support is provided having the horizontal upper platform 80 with two pairs of dependent legs 82 which also fit between the stiles of a section, as best seen in FIGS. 2 and 6. Each leg 82 is provided with an inverted U-shaped spring clip 84 secured at its bight to the bottom of the leg and adapted to resiliently clamp the upper rungs 20 of the

ladder sections

12 and 14 between the stiles and the

clips

76, 78. Referring to FIG. 6, the arrow C indicates the direction in which the platform is moved to clamp the platform to the step ladder. When it is desired to remove the top support for purposes of folding the step ladder, or to form an extension ladder, the platform 80 is merely lifted in the opposite direction to spread the arms of the spring clips 84 and release the ladder rungs 20.

When it is desired to fold the step or extension ladder, this may be easily done by grasping the heads 56 and moving the appropriate locking studs 52 from notches 64, through slots 62 and along slots 60 to withdraw the locking members 50 so that they no longer fit within a stile of an adjacent section but are positioned completely within the stile of the next section.

The unlocked sections may then be turned about the pivots of the hinges 24. However, if the adjacent sections are locked in their angular relation, as for

example sections

12, 14 in FIG. 1, these sections must first be unlocked by lifting the ends 40 of the latch bars 36 to remove the pins 42 from the openings 46 in the stiles. The sections may then be turned and folded or unfolded, the pins 42 riding on the outer walls of the stiles as the hinges 24 turn with respect to the stiles pivoted thereto.

Should it be desired to form one, or two, small step ladders, the cotter pins 36 are removed from the upper hinges of the ladder illustrated in FIG. 1, and the hinge straps 26 are flexed to remove the studs 34 from the openings 30 in the straps. This enables complete separation of sections and 12 from

ladder sections

14 and 16. Each of the separated parts of the ladder may then be formed into a small step ladder, as illustrated in FIG. 9. The hinges and latch pins 42 lock the section 10 at the desired angle to section 12 and similarly section 14 to section 16 in the manner as previously described with respect to

sections

12 and 14. The sections are desirably provided with additional anti-spreading means in the form of pivoted bars 86 each having a hook end 88 and swingable to engage the hook ends over rungs 20 of an adjacent spread section. Once the two small step ladders have been formed and placed in spaced alignment, a platform 90 comprising a loose panel may be placed between the stiles and seated on the top rungs of both step ladders as illustrated in FIG. 9. It Will be obvious that the platform 90 may be provided with the spring clips such as 76 and 84 to more firmly retain the assembly together.

Although certain specific embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

1. A combination folding step ladder and extension straight ladder, comprising a plurality of sections each having spaced longitudinal stiles connected by transverse rungs, the contiguous ends of the stiles of adjacent sec tions being curved to permit relative turning of the sections, hinge means located along the longitudinal center lines of said stiles and continuously securing adjacent sections to each other for relative turning movements in either direction from a folded condition in which the sections lie contiguously in adjacent planes to a first unfolded position in which the sections are in alignment to form a straight extension ladder and to a second unfolded position in which the sections are at an angle to form a step ladder, said hinge means having latch means cooperable with a stile of one of said adjacent sections to secure said sections in said second unfolded position, and lock means mounted on a stile of at least one section and movable longitudinally of the stile to engage an aligned stile of an adjacent section for securing the sections in said first unfolded position.

2. A ladder according to claim 1 wherein said curved, contiguous ends of the stiles of adjacent sections are in abutting relation when the adjacent sections are in alignment.

3. A ladder according to claim 1 wherein said stiles are tubular and said lock means comprises a tubular member slideably housed within a tubular stile of at least One section and movable longitudinally of the stile to protrude into an aligned stile of an adjacent section for securing the sections in said first unfolded position, and manually manipulative means for moving said lock means.

4. A ladder according to claim 3 wherein said manually manipulative means includes a lateral detent member projecting outwardly of the ladder from the tubular member through its associated stile, said lock means housing stile having a longitudinal slot in a laterally outside wall through which said detent member passes.

5. A ladder according to claim 4 wherein said tubular member is provided with a transverse slot in which said detent member is slideable and said longitudinal slot of the stile is also provided with a communicating transverse slot for reception of said detent member.

6. A ladder according to claim 5 wherein said transverse slot of the stile is provided with longitudinal notches at one end to receive and latch said detent member.

7. A ladder according to claim 1 wherein said hinge means comprises studs projecting from stiles of adjacent sections and a strap freely pivoted on said studs, said strap being readily removable from at least one of said studs to enable separation of the associated pair of sections, said associated pair of sections when separated being still connected to other sections and being unfoldable to provide separate step ladders for support of a platform therebetween.

8. A ladder according to claim 7 wherein said latch means on the hinge means for locking the sections in said second unfolded position comprising a resilient strip having a locking pin mounted on said hinge strap and detent means formed on one of the stiles to which the strap is pivoted, said locking pin being releasably engageable under resilient pressure of said strap with said detent means to lock the associated sections together at a preselected angle.

9. A ladder according to claim 3- in combination with at least one additional section having tubular stiles connected by rungs to form an extension section, each tubular stile of said extension section having a tubular projection of smaller cross section projecting from one end thereof for removable insertion into a tubular stile of the uppermost section of said plurality of sections when unfolded and secured in alignment.

10. A combination folding step ladder and extension straight ladder adapted to be unfolded from a compact package to form either a self supporting step ladder or a straight extension ladder, comprising a plurality of sections of substantially identical size and dimension, each section having tubular stiles connected by fixed rungs, hinge means connecting adjacent sections for relative turning movements from a folded condition in which the sections lie contiguously in adjacent planes to a first unfolded position in which the sections are in alignment and to a second unfolded position in which the sections form an angle, said hinge means including latch means for securing said sections in said second unfolded position for use as a step ladder, lock means slideably housed within a tubular stile of at least one section and movable longitudinally of the stile to protrude into an aligned stile of an adjacent sectionfor securing the sections in said first unfolded position, and manually manipulative means other than said rungs for moving said lock means, said hinge means comprising studs projecting from stiles of adjacent sections and a strap freely pivoted on said studs, said latch means on the hinge means for locking sections in said second unfolded position comprising a spring bar fastened at one end to said strap of the hinge means, said spring bar having a pin near the other end, an opening in said strap, a second opening in one of the stiles to which the strap is pivoted and so arranged as to align with the first opening when the associated sections are unfolded to form a step ladder angle, and said pin of the spring bar being enterable into said aligned openings to lock the sections in said angle.

11. A combination folding step ladder and extension straight ladder adapted to be unfolded from a compact package to form either a self supporting step ladder or a straight extension ladder, comprising a plurality of sections of substantially identical size and dimension, each section having tubular stiles connected by fixed rungs, hinge means connecting adjacent sections for relative turning movements from a folded condition in which the sections lie contiguously in adjacent planes to a first unfolded position in which the sections are in alignment and to a second unfolded position in which the sections form an angle, said hinge means including latch means for securing said sections in said second unfolded position for use as a step ladder, lock means slideably housed within a tubular stile of at least one section and movable longitudinally of the stile to protrude into an aligned stile of an adjacent section for securing the sections in said first unfolded position, and manually manipulative means other than said rungs for moving said lock means, said hinge means comprising studs projecting from stiles 7 8 of adjacent sections and a strap freely pivoted on said 445,453 1/91 Nowland 1822'7 studs, said latch means on the hinge means for locking 467,685 1/92 Hammon 182-l16 the sections in said second unfolded position comprising 570,469 11/96 Furgason 182119 a resilient strap having a locking pin mounted on said 2,183,251 12/39 Beggs 182163 hinge strap and detent means formed on one of the stiles 5 2,963,761 12/60 Haydock 297-153 to which the strap is pivoted, said locking pin being re- 3,078,953 2/63 Silen 182-163 leasably engageable under resilient pressure of said strap with said detent means to lock the associated sections FOREIGN PATENTS together at a preselected angle. 1,194,813 5/ 59 France- 10 343,539 11/21 Germany.

References Cited by the Examiner UNITED STATES PATENTS 96,495 11/69 Smith 182-416 HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner.

Claims

1. A COMBINATION FOLDING STEP LADDER AND EXTENSION STRAIGHT LADDER, COMPRISING A PLURALITY OF SECTIONS EACH HAVING SPACED LONGITUDINAL STILES CONNECTED BY TRANSVERSE RUNGS, THE CONTIGUOUS ENDS OF THE STILES OF ADJACENT SECTIONS BEING CURVED TO PERMIT RELATIVE TURNING OF THE SECTIONS, HINGE MEANS LOCATED ALONG THE LONGITUDINAL CENTER LINES OF SAID STILES AND CONTINUOUSLY SECURING ADJACENT SECTIONS TO EACH OTHER FOR RELATIVE TURNING MOVEMENTS IN EITHER DIRECTION FROM A FOLDED CONDITION IN WHICH THE SECTIONS LIE CONTINGUOUSLY IN ADJACENT PLANES TO A FIRST UNFOLDED POSITION IN WHICH THE SECTIONS ARE IN ALIGNMENT TO FORM A STRAIGHT EXTENSION LADDER AND TO A SECOND UNFOLDED POSITION IN WHICH THE SECTIONS ARE AT AN ANGLE TO FORM A STEP LADDER, SAID HINGE MEANS HAVING LATCH MEANS COOPERABLE WITH A STILE OF ONE OF SAID ADJACENT SECTIONS TO SECURE SAID SECTIONS IN SAID SECOND UNFOLDED POSITION, AND LOCK MEANS MOUNTED ON A STILE OF AT LEAST ONE SECTION AND MOVABLE LONGITUDINALLY OF THE STILE TO ENGAGE AN ALIGNED STILE OF AN ADJACENT SECTION FOR SECURING THE SECTIONS IN SAID FIRST UNFOLDED POSITION.