US3143185A - Multi-purpose folding ladder - Google Patents

Description

Aug. 4, 1964 G. WENGER 8 MULTI-PURPOSE FOLDING LADDER Filed April 30, 1952 v 2 Sheets-Sheet 1 i I I a I 5 1 I I 5 a 5 1 :i I I I v -.DVVE/VTOR GERHARD WENGER BY w/ y A TTO/P/VE Y 4,1954 QWENGER 3,143,185

MULTI-PURPOSE FOLDING LADDER 1 I Filed April 30, 1962 vZSheeigs-Shet; 2

INVENTOE ATTORNEY GERHARD WENGER United States Patent 3,143,185 MULTl-PURPQSE FOLDENG LADDER Gerhard Wenger, Hehhelstrasse 5, Murrhardt, Wnrttemherg, Germany Fiied Apr. 30, 1962, Ser. No. 191,118 Claims priority, application Germany May 3, 1961 3 Claims. (Cl. 182-24) This invention relates broadly to ladders and more particularly to a very expedient and Versatile multi-purpose folding ladder.

It is known, from the prior art, to join two ladders or ladder sections by means of hinges at one end to form a double ladder which can be used from both ends. It is also customary in prior art teachings to join several ladder sections, end to end, to temporarily obtain a step ladder having greater reach. But the known ladder constructions of the prior art can only be used for a limited purpose, and in most cases their transportation is rather difiicult, requiring sometimes even specially equipped cars or trucks to transport the same. It is therefore one of the objects of the invention to provide a construction of multi-purpose folding ladder in which these disadvantages are eliminated.

Another object of the invention is to provide a construction of relatively long reach, multi-purpose ladder which can be adjustably positioned into a variety of configurations and which can be folded into a small volumetric space for efficient transportation in the ordinary automobile.

Still another object of the invention is to provide a construction of joint hinge for a multi-purpose ladder which is rugged and simple in construction and provides means for automatically locking adjacent hinge sections together when moved into axial alignment.

A further object of the invention is to provide a construction of multi-purpose folding ladder having simple fail-safe locking means intermediate adjacent folding ladder sections.

Other and further objects of the invention reside in the joining hinge structure of the ladder, the manner in which duplicate hinge structures can be utilized throughout the length of the ladder construction, and in the means for securing adjacent ladder sections in the unlocked position; and still further objects and advantages of the invention are set forth more fully in the specification hereinafter following and which will become apparent by reference thereto with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view through an open hinge portion of the ladder structure according to the invention, the view being taken substantially along line II of FIG. 2 and showing the hinge portion removed from the ladder for greater clarity;

FIG. 2 is a top plan view of the ladder hinge joint in the open position as shown in FIG. 1;

FIGS. 3-6 are schematic views showing several possible uses and adjusted positions of a ladder according to the invention with the ladder, according to FIGS. 3 and 4, being shown as seen from one side; and the ladder, according to FIGS. 5 and 6, being shown as seen from the opposite side; and

FIG. 7 is a vertical transverse sectional view through the rungs of a ladder according to the invention, showing the manner in which adjacent hinge members are positioned with respect to each other.

The invention is characterized by several pairs of ladder sections, joined with each other by hinge members which can be locked in axially extending position, which is the preferred operating position, and which can be pivoted at each end of a ladder section by 180 degrees about the longitudinal axis of the ladder sidepiece. This 3,143,185 Patented Aug. 4, 1964 has the result that the ladder can be folded accordion-like and stored conveniently in the luggage compartment of an ordinary passenger car. If all hinges of the ladder according to the invention are extended in axial alignment, a step ladder having a relatively long reach is ob tained, as shown in FIG. 3. If the central pair of ladder hinges is bent or pivoted relatively back upon themselves,

a double ladder structure is obtained, similar to that shown in FIG. 4, which can have rigid or moving legs, depend ing upon whether both halves of the ladder are held in their extreme position by rigid pairs of struts or by pairs of chains. If the center hinges are left in locked, extended position so that the central ladder sections are disposed in axial alignment, and the adjacent hinges on either side are bent oif by approximately degrees, a high working platform, such as shown in FIG. 5, is obtained. If the center hinges are released in addition to the hinges on either side thereof, two articulated roof-ladder halves are obtained, on or between whose rungs can be placed boards to form a working surface at a selected level, depending upon which ladder rungs are utilized. If only the hinges adjacent the upper end of the ladder are turned or pivoted by approximately 110 degrees, a wall ladder is obtained having a certain distance from the wall, as shown in FIG. 6.

Preferably, the hinges arranged at opposite ends of the same ladder section sidepieces are disposed degrees relative to each other so that the hinge axes lie on opposite sides of sidepieces. This way it is possible to use only one universally fitting hinge joint and, nevertheless, have the hingelock release handle 21 always disposed on the outside of the ladder, thus rendering it easily accessible for actuating thehinge release bolt 16. This objective is enhanced by the fact that acontrol button 21 is provided, having apin extension 2t), which extends into therelease bolt 16 transverse to its axis, and which protrudes therethrough and to the outside of the hinge assembly on either side thereof through slots provided in the side walls oflink box 2 parallel to therelease bolt 16. This way the same movement perpendicular to the sidepiece toward its center will unlock the ladder hinge joint independent of the accidental position of the joint with regard to its ladder parts, although the perpendicular movement for oppositely disposed joints will be in opposite directions.

Referring to the drawings in greaterdetail reference characters 1 and 2 represent boxes of sheet metal or the like, each having a pair of tongues orear pieces 3 and 4, respectively, extending from the innernarrow sides 5 and 6, and positioned in superimposed relation. The ear pieces are provided with apertures in registration and are rotatably or pivotally connected with each other by a hinge pin 7, such as a machine screw having ahexagonal head 8 and a cooperating fastening nut 9, extending through the apertures. A spacer member orsleeve 10, disposed on hinge pin 7 intermediate opposite pairs of superimposed ears, provides a firm connection betweenboxes 1 and 2 at their upper ends when nut 9 is tightened on screw 7, but enables the hinge box sections to freely pivot with respect to each other. The spacer sleeve and removable pivot pin assembly enables individual ladder sections to be easily replaced by other ladder sections, such as sections of greater length, or with different rung spacing, etc., or sections constructed of different material such as insulation material for working around electrical power lines and the like.

Theinner end portion 11 of the box 1 is widened or expanded as indicated and can be folded or pivoted over theinner end portion 12 of thebox 2, to thus overlap and encompass the same when thebox members 1 and 2 are positioned in axial alignment, to further increase the strength of the joint between adjacent ladder sections.

latch bar 16, whose rear end portion is supported in slid- 'ing relation in an aperture in asmall crossplate 17. Areturn spring 18, having one end in abutting engagement withplate 17, is disposed to press against acotter key 19, or the like, inserted through thelatch bar 16, to thus normally urge the bar outwardly through the aperture '15. Alock release pin 29 is disposed to move trans -versely in a passage through thelatch bar 16 and extends into sliding contact with slots in either side wall ofbox 2, the slots being disposed parallel to and extending longitudinally with the axis of thelatch 16, and being of a length to allow the latch to be retracted into aperture 15. Thelock release pin 20 is provided with a lock control orrelease button 21 on one outer end thereof and the opposite end protrudes somewhat outwardly from the opposite sidewall ofbox 2 to form a locking member to be described. Acotter key 22 or the like is provided throughrelease pin 20 inwardly of the box sidewalls and aspring 23 is disposed intermediate the key and latch bar to normally urgerelease button 21 toward the box wall and the opposite end ofpin 20 to an extended position as shown in FIG. 2. When the two hinge sections orboxes 1 and 2 are pivoted to their axially aligned position, the front end or extended terminating end ofpin 20 is first forced flush with the box sidewall against the pressure ofspring 23 by abevel portion 24a on the enlargedinner end portion 11, which bevel portion tapers downwardly in a direction and in alignment with angular slot 2s. Then the front end oflatch bar 16 contacts the outwardlyinclined bevel portion 24b on the widenedend portion 11 of box 1, and the latch is moved inwardly against the tension ofreturn spring 18, temporarily into its release position until the boxes reach their axially aligned positions at which time the front end oflatch 16 and the terminating end ofpin 20 snap intoapertures 25b and 25a, respectively, in the sidewalls of box 1. Anangular slot 26 is provided in the widenedendportion 11 of box 1,opposite bevel portion 24a, as particularly shown in FIG. 1, to allow a passage for the end ofrelease pin 21 carryingrelease button 21 as the boxes are pivoted to their locked positions. The slot 29 'is provided with a sloping edge since thepin 20 moves inwardly with the latch as the sections are moved together. When the boxes snapinto locked position the button end ofpin 20 moves forward in the short transverse portion ofslot 26. The slot provides for unhindered movement of the release button.

In the locked position of the hinge, neither pressure on therelease buttonalonanor a force exerted only on the latch bar in the direction of the release movement, can effect the unlocking of the ladder hinge joint. Only the positive accident-proof combined movement of therelease button 21 away from the link box, by pulling outwardly on the same, and then simultaneously moving thebutton 21 and itspin extension 20 toward the inside of the ladder, can the'unlockingof the hinge joint be efiected. The first movement removes the end of pin 24) from locked engagement withaperture 25a and the second movement removeslatch'bar 16 from'locked engagement with'aperture 25b, thus leaving the boxes free to rotate with respect to each other. Thus it can be seen that this arrangement provides a fail-safe locking hinge which cannot become unlocked by any accidental movement.

FIGS. 3 to 6 show some of the various adjusting possibilities-of a ladder according to the invention, and also show pairs ofbracing struts 27, 28, for maintaining the ladder in the selected adjusted position, which are arranged on both sides of the ladder and which are articulated at 29 and 30, respectively, onside pieces 33 and 34 by bolts or the like'in the vicinity of thecommon hinge joints 31 and 32. The free ends of the bracing struts are provided with slots to slidably engage fixed pins on the adjacent ladder sections and be tightened thereagainst with wing nuts or the like on said fixed pins. When used as a step ladder according to FIG. 3, the pairs ofbracing struts 27 and 28 are not needed. When in use they are held in the represented position, for example, by Wing nuts or the like (not represented). When used as a rigid double ladder according to FIG. 4, only thestruts 27 are used, and by inserting a bolt (not represented) into the slot at the free end of each strut, which bolts are rigidly connected on the outside of the sidepieces of theadjoining ladder section 35 and are provided with a cooperating wing nut for holding the struts in this position for rigidly bracing the double ladder structure. When the multi-purpose ladder according to the invention is used as a scaffold ladder, according to FIG. 5, both pairs ofstruts 27 and 28 are utilized. When used as a wall ladder with wall distance according to FIG. 6, only thebracing struts 28 are used, while thestruts 27 remain in rest position pivoted back upon thesidepiece 33.

In another embodiment of the invention, accordingto FIG. 7, in lieu of bracing struts, pairs'ofguide rods 42, 43 are arranged on the inside of thesidepieces 34 and 36, at 33 to 41. The guide rods are somewhat spaced from the sidepieces and are provided on their lower or outer ends, as seen from thecentral hinge 37, with a sharplyrecessed part 44, 45 into which fit theterminal links 46, 47 of theholding chains 43, in such a way that theterminal links 46 and 47 cannot slide up along theguide rods 42 and 43, even under maximum tension of thechains 48, since therecessed parts 44, 45 extend toward the center of the chain, thus preventing collapse of the ladder.

If the ladder, according to FIG. 7, is to be used, for example, as a regular long reach ladder as shown in PEG. 3, theladder sections 34, 35 and 33, '36, respectively are moved closer together to render the chains slack, and thechains 48 are lifted and slid upwards on the rods so that their ends-46 and 47 no longer lie in therecessed parts 44 and 45 of theguide rods 42 and 43. Thehinge 37 is then pivoted to its axially aligned locked position and in this position theends 46 and 47 of thechains 48 are then held according to the invention in stretched or taut position by the outer oropposite ends 49 and 50 of theguide rods 42 and 43, so that thechains 48 in no way interfere with the general use of the ladder, in case it is used for any other purpose.

Thus it can be seen that it is possible to use the multipurpose ladder according to the invention, with this modified holding means, not only as a rigid double ladder, as shown in FIG. 7, but also as a painters ladder or the like, which-can be moved in known manner on the floor by the person standing on the ladder, without the necessary and prescribedholding chains 48 hindering the locked-position of the central ladder hinge joint.

FIG. 7 also clearly shows that thehinge 37 is arranged turned by degrees about the hinge axis with regard to the'hinge 3310f thesame sidepiece 36 and with regard to thehinge 32 respectively of thesame sidepiece 34. In addition, FIGS. 3 and 4, which show the same side of the ladder, which is opposite from the side shown in FIG. 7, also show that the handles orrelease buttons 21 are arranged oneach outer side, so that the hinges at the ends of the same ladder section are turned by 180 degrees about the-hinge axis. This then enablesthe same hinge structure to be used throughout the ladder with the ladder sections being connected to the hinge boxes by means of bolts, pins, 'rivets, or the like, passing throughthe holes in the boxes shown in FIG. 1 and through the ends of the ladder sections.

The multi-purpose ladder according to the invention can be made of any material. Particularly advisable, however, for working under live wires, is a ladder of polyester with glass fiber addition, which is characterized 'not only by its low weight, but also by its excellent insulating properties. This material also has the advantage that the hinge boxes can be attached right away to the side pieces or made integral with them.

While I have described my invention in its preferred embodiments, I realize that modifications may be made, and I desire that it be understood that no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A folding multi-purpose ladder comprising a plurality of ladder sections, pairs of hinge means pivotally connecting the ends of adjacent ladder sections of said plurality of ladder sections, the pivots of said hinge means connected to opposite ends of each ladder section positioned on opposite sides of the ladder plane to allow zigzag folding of said plurality of ladder sections, each of said hinge means including a pair of link boxes connected to the ends of adjacent ladder sections and pivotally connected adjacent their inner ends with the inner ends disposed in overlapping relation when said boxes are pivoted in axial alignment, a latch bar connected interior of one of said link boxes for movement transverse to the axis of the pivot and extending through registered apertures in said overlapping inner ends to lock said link boxes and ladder sections in axial alignment, a return spring connected to said latch bar to normally urge it to the locked position, said one link box having slots in the sidewalls thereof extending parallel to said latch bar, a latch release pin extending transversely through said latch bar in sliding relation and projecting through said slots, a pair of beveled surface portions carried by the other link box sloping inwardly from the inner end and terminating in apertures through the walls thereof, one of said beveled surface portions positioned to engage the end of said latch release pin and the other beveled surface portion positioned to engage the projecting end of said latch bar as said link boxes and ladder sections are pivoted into axial alignment to move said latch release pin relative to said latch bar and retract said latch bar and release pin against the force of said return spring to a release position and release the same into engagement with the apertures at the ends of said beveled portions to automatically lock said link boxes and ladder sections in end to end axial alignment.

2. A folding multi-purpose ladder as set forth in claim 1, including a release knob connected to the opposite end of said latch release pin exterior of said link boxes, and the hinge means of each pair of hinge means being identical and connected intermediate adjacent ladder sections such that all the release knobs are directed outwardly of the sides of the ladder.

3. A folding multi-purpose ladder as set forth in claim 1 in which said plurality of ladder sections include hingedly connected central ladder sections having sidepieces, guide rods rigidly connected at opposite ends to the sidepieces of the adjacent central ladder sections and extending longitudinally and substantially coextensive therewith, a bracing chain connected for sliding movement at opposite ends on the guide rods of adjacent central ladder sections and bridging the same, said guide rods terminating adjacent the hinge means joining said adjacent central ladder sections such that said chain is held taut intermediate said rods and in longitudinal alignment therewith when said central ladder sections are disposed in axial alignment, and bent portions provided on said guide rods at the opposite ends for engaging the chain and holding it taut at an angle to said guide rods when the central ladder sections are pivoted out of alignment.

References Cited in the file of this patent UNITED STATES PATENTS 70,933 Abbott Nov. 19, 1867 1,508,029 Segal Sept. 9, 1924 2,012,592 Skiba Aug. 27, 1935 2,108,774 Lipert Feb. 15, 1938 2,885,132 Campbell May 5, 1959 FOREIGN PATENTS 6,884 Great Britain Apr. 21, 1891 6,223 Great Britain Mar. 25, 1901 404,248 France June 21, 1909 534,068 Canada Dec. 4, 1956

Claims (1)

1. A FOLDING MULTI-PURPOSE LADDER COMPRISING A PLURALITY OF LADDER SECTIONS, PAIRS OF HINGE MEANS PIVOTALLY CONNECTING THE ENDS OF ADJACENT LADDER SECTIONS OF SAID PLURALITY OF LADDER SECTIONS, THE PIVOTS OF SAID HINGE MEANS CONNECTED TO OPPOSITE ENDS OF EACH LADDER SECTION POSITIONED ON OPPOSITE SIDES OF THE LADDER PLANE TO ALLOW ZIGZAG FOLDING OF SAID PLURALITY OF LADDER SECTIONS, EACH OF SAID HINGE MEANS INCLUDING A PAIR OF LINK BOXES CONNECTED TO THE ENDS OF ADJACENT LADDER SECTIONS AND PIVOTALLY CONNECTED ADJACENT THEIR INNER ENDS WITH THE INNER ENDS DISPOSED IN OVERLAPPING RELATION WHEN SAID BOXES ARE PIVOTED IN AXIAL ALIGNMENT, A LATCH BAR CONNECTED INTERIOR OF ONE OF SAID LINK BOXES FOR MOVEMENT TRANSVERSE TO THE AXIS OF THE PIVOT AND EXTENDING THROUGH REGISTERED APERTURES IN SAID OVERLAPPING INNER ENDS TO LOCK SAID LINK BOXES AND LADDER SECTIONS IN AXIAL ALIGNMENT, A RETURN SPRING CONNECTED TO SAID LATCH BAR TO NORMALLY URGE IT TO THE LOCKED POSITION, SAID ONE LINK BOX HAVING SLOTS IN THE SIDEWALLS THEREOF EXTENDING PARALLEL TO SAID LATCH BAR, A LATCH RELEASE PIN EXTENDING TRANSVERSELY THROUGH SAID LATCH BAR IN SLIDING RELATION AND PROJECTING THROUGH SAID SLOTS, A PAIR OF BEVELED SURFACE PORTIONS CARRIED BY THE OTHER LINK BOX SLOPING INWARDLY FROM THE INNER END AND TERMINATING IN APERTURES THROUGH THE WALLS THEREOF, ONE OF SAID BEVELED SURFACE PORTIONS POSITIONED TO ENGAGE THE END OF SAID LATCH RELEASE PIN AND THE OTHER BEVELED SURFACE PORTION POSITIONED TO ENGAGE THE PROJECTING END OF SAID LATCH BAR AS SAID LINK BOXES AND LADDER SECTIONS ARE PIVOTED INTO AXIAL ALIGNMENT TO MOVE SAID LATCH RELEASE PIN RELATIVE TO SAID LATCH BAR AND RETRACT SAID LATCH BAR AND RELEASE PIN AGAINST THE FORCE OF SAID RETURN SPRING TO A RELEASE POSITION AND RELEASE THE SAME INTO ENGAGEMENT WITH THE APERTURES AT THE ENDS OF SAID BEVELED PORTIONS TO AUTOMATICALLY LOCK SAID LINK BOXES AND LADDER SECTIONS IN END TO END AXIAL ALIGNMENT.

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