US2567302A - Foldable ladder - Google Patents

Description

Sept. 11, 1951 51p 2,567,302

FOLDABLE LADDER Filed June 19, 1948 a W e 3;

' INVENTOR.

Attorney Kcr l' SIP MA MM Patented Sept. 11, 1951 ATEN .QF CE' FOLDABLE? LADDER j Karel Sip, S lany, Czechoslovakia Application June-l9, 1948, Serial No; 34,035

In'Cfzechoslovakia August 18, 194'7 a The; invention is concerned with foldable-ladtiers of the type which compriseswa pair of side structures each in the form of lazy tongs; y r More specifically, theinvention. is concerned with a development-of this type of ladders which makesthem particularly useful for various pure poses qingthe building art's, such. as for painting and decorating rooms; installation and maintenance -work,' or the *likem- It .is a primary object of the prevention to reduce still "further the space; which ithe -conventional-{ladders of this lazytongs' typeoccupy when folded to-, gether and furthermore :to reduce the weight of suchladders and simplify their constructionwhile enhancing the. facility 'of foldingthose ladders together and setting them. up rapidly without the necessity oi-taking oiforjoining parts; v i.

.It is thusan object of the invention .to mak the ladder foldable together to such dimensions that it may be handled as'any. gportablepiece of luggage and may thus be placed, 1asa .piece of luggage opener in a properly'dimensioned suitcase or as a package, into the luggage compartment or: may be taken'into-the interior of: an automobile or into any public transportation means; a possibility of great importancefor painters, varnishers, decorators, upholsterers, electricians; plumbers, or othe1;- mechanics,- especially where it is necessary that-vthe mechanie orj other crafts man; quickly. reaches. the working place for -care rying out an urgent repair orother work l The side structures of. the foldable ladderof the invention are composed of arm and links-ing terconnecting the arms; by means of. pivots dis: posed: onthe arms and links at -points equidis tantly spaced apart from on another. By means of these pivots the links are pivotally connected at one oftheir. ends with one end of one of said arms, at a median, point with a median pointof the subsequent arm, and at the other end with the other end of the next succeeding arm; The arms and links with their pivotsthus constitute the side-structures of the ladder,in the'form of c015 lapsible and vexpansible rhomb mechanisms. In these ladders of the invention equally dis-Q posed. arms ofboth side structuresare integrally shaped asopen U-shaped stirrups. The bases oi the U -shaped stirrups-interconnect' the side struc-j tures and form the steps of the ladder. These bases orsteps arethe sole interconnection be-j tween the sidestructures. I r I The ladder when folded together thus forms aframe of U-shape, the inner space of which, when the ladder is'packed as a piece of luggage or in a suitcase or otherwise, may be utilized for cc mmoda n he too m t r als or t like. Thus considerable space may be saved-in the luggage compartment of acar orinatru ckt- Locking devices may be provided. for con-nect ing two adjacent elements of .the rhomb mechanisms in, fixed angular relationship for thus locking the ladder against inadvertent collapsing andexpanding. 4, I The ladder'ofthe invention is constructedas a double ladder comprising ;two ladders as de-. scribed, and pivotally. joined together by means of hinges provided at the, sidestructures, In addition to the locking devices for holding. elements of therhomb mechanisms in fixed angular relationship, braces may be provided which con= nect two elements, one at each ladder, and adjacent to the hinges, in .fixed angular relation-r.

ship and thus lock both ladders in extended straight position, one ladder in extension of the other, when itis desired to employ the double ladder as a ladder of double the length of an in;

- dividual of the ladders.

- are of a width andthe appertainingarms of a ings are intendedto b ill length greaterthan those of .the otherof the lad; ders thus suilicient, when the stirrups andlinks are folded together, to accommodate in the space confined at three sides by the juxtaposed stirrups of the first named-ladden-the stirrups and-links of the second ladder. when-likewise folded ,to-.

gether. 3 v;

Other objects and features of the invention will become apparent as the specification proceeds, The nature :of my inventionwill now be more fully described withreference to the accompanying drawings which form. part of this specificae tion. and which by; way of example illustrate, an embodiment of -:myinvention I It will be readily understood that the draw; trative of theinvem tion and not limitativeo fits scope; and that the invention maybe embodied in other forms without departing from theprinciple underlyingmy invention and from the-ambit of my appended claim. y In-thedrawingsz: -Fig. l is aside elevati n'. of a double ladder;. in accordance with theinvention;

wise'lon ia 3 scale 'of the double ladder when extended into straightened-out position, one ladder in extension of the other; and,

Fig. 6 is a, perspective, on the same scale as Figs. 1 to 3, of the double ladder in folded position.

In the vdrawings, ,the .two members .or,.legs of the doubleil'afdiier.areedcsignated 'by =ll :and F2. The two members ll, l2 are joined'togetherby hinges l3, l4. Each member or ladder comprises a series of U-shaped st-irrups l5 and I6, respectively, each of the stirrups l5 constituted'zbyra step I! as a base and two lateral ,arms [9,

and each of the stirrups I 6. by a'step "it and two lateral arms 2|, 22. Arms rtil,s20me:inter connected by links 24, and armsi'2l, 12y

links 26, 21, respectively, and thus form side structures of the ladder members.

The U-shaped stirrups and the links may be of *any 'suitable vmaterial, such as =sheetsmaterial, strips of iron, steel, "brass, alum'inum, or sothzer metal, or wood -'or :any other appropriate, =also synthetic =material. Reinforcement :ribs ma he provided such 'zas shown amt on the surfacessof the links.

Pivots in the form of screw bolts, rivets, or :izhe like, *two =on each end *meniber 'and three on :all others, are #provided on the =arms and links .and disposed-equidistantiy spacerl apartifrom onesanother f or connecting ithe arms :and -links #to sidestructures rat "both -sides of the ladder. More specifically, the-links :and 26 2:1 :are pivotally connected by -means -of pivots :31 :at one of *thir ends, -the-1mper end, with one end, Ithe step en'd or' front-endxof the arm of one of the U shaped stirrups; %by means or 'pivots 32 at a media point with a median *point of the arm of' thesubsequenvstirrup,andhby meanso'f pivots 33 at *the other, the lower=end with -the upper -or rear end of the arm of the next succeeding :U

shaped stirrup. and links thus cons'titute with their fpiVOtS, fthe *sitie structures of :the ia'd'rierin rthe *formof-"coliapsible andexpansible rhomb mechanisms.

,Each'sirle struetirreofthe double' ladder isgprovided vat 'its root end, rat the end links 34 ifor in staneeywith agprojection fl, constitutinga -broad supporting base =for the "respective =sides'trueturezofthe laiider.

Iif'theenibodimerit 'illustratedthere is'arrange'd between *the lowermost links M and the appertaming arms 36 a locking device oonsistingin'the example show 'of an arched proiection *3! of the links 14 "with locking means, such -as holes andmegsxscreW- bolts ypins; assgeneraily indicated at "38, engaging the elements -34. *By means of such-orother locking devices, -tWo adjacent elements of the 'rhombqnechan-ism-may' be connected in fixed angular' relationship and*the-sidestructures, whememctcrlp thus be locked against undeSired-cllapSing andexpanding.

{Hyuneans 'of theselocking-devices, adapted to be "set in-various loekingmositions and by -selecat various lengths. on anincline'd-or uneven'floor or on a staircase, or the'like. *Ihedo'cking devices 31, 38, of one member (l2) are so set that this member is shorter than the other (I I) and the different heights of the bearing surfaces are compensated. The lengths of the two members will be so set that the members generally include the same angle with the vertical.

.The .two.memhers l i, J2 ..of the double ladder raremreierablyhinged together by :means of detachable bolts, generally indicated at l3, I. When this joint is disconnected, each member may be employed by itself as an independent unit randeserve as a foldable simple ladder. On the other hand, the two members with their hinges "joined maybe fully extended into straight posiltiomzonelladderttlz) in extension of the other (I I) Arsingiedeader of double extension or length is thus obtained, as Fig. 5 illustrates. The two 'members H and I2 will then be locked individually by locking devices such as described with reference to elements 131, "3'8, rand,.-simiiarly, =in their position :one against lthe other-byfiocking means such as Ebraces 2A0 'kWhiQh connect fby "means oi.- detachable elements, i such as screw bolts, thumb screws, :or others, itWO elements :such iasflinks M; 42, 'iFig. 76, 50118 -at r-each ladder, an'd a'djacent -to the v hinges -l 3, :M, -ain fixed :angular rre'lation'ship so zthat both ladders 5H, I2 :are locked-iin extended zstraight position, :one :ladder inextension-o1 theother. t-If ithe iladder isi'to iol de'd together i into the position shown on Big. 36, thelocking devices '31, '38 are unlocked, .all members of the ladder are released rand may now collapse, the arms 19, 10 end-4| 22 --;and.- 1inks 24, "-25 rand- 263 21 being piv' oted about "their =-piv0ts 6| 32, until the r U- shaped stir-raps and thel-inkswlie close together, as Fig. #6 illustra'tes. in order to =reduce as ier "as possible the dimensions of -the #fol'ded ladder, in accordance with the invention, the steps I or the SU shapeid stirrups or one the ladders ('H) areef a-=-width and -the appertaining arms H3, 20 :01. a ieng-th greater athan those of the steps I8 and the--a=rms 2'l 22=of+the other ladder t.2,- thus suflicientpwhen the -stirrups i l5 andlinks 2 4, 25 are folded *together, aaecommoclate in the :space confined :on '-three *sides by the posedstim'ups, -15, -of one -ladder, H, the links '25, -21 and stiPrups MS "of the 'other ladder, 42, when *likewise fielded together. Conveniently, the ladders are so joine'd by '-'h-inges -13, 'M that the steps of at least 'the *wider ladder are directed to the outside. -Otherwise, the =la'd'rlers' when to be ielded *together, are to be turned one-over the other at their eommon hinges I -3 H.

1 claim:

7 A double ladder consisting :of a pair of foldable ladders 3each of the type "which comprises a pair ;of side structures each composed of arms and links: and with ,pivots *dispose'dron said arms. and "link for connecting 'said ar-ms "and links at points "e quidistantly spaced apart ,from one another, said links; being pivotaliy 'connectefi b means .gof sai'd pivots, atone of their ends with one end of one of said arms, at amedian point W hm dian p n o h jsu se uent m and at the other .end with j the other end "of i the ,next succeed n Jarm, arm andi1ink.;secti n "be ween and with their gpivot -t us or s .c llap ibl and expansible rhomb mechanisms; equally disposed arms of both. id t uctur -beflne nt rall Shaped .as een U-shapes ls i uns. :the bases ,of'ithe U :shap .stirrup nterc nn ct ns the side. structures. an i'iormine hestem .O the ladders; each of sai s d stru ture h vin hinge for pivotally joining sai'd ladders, the steps of the U-shaped stirrups of one of said ladders being of a width and the appertaining arms of a length greater than those of the other of said ladders. thus sufiicient, when said stirrups and said links are folded together, to accommodate in the space confined at three sides by the juntaposed stirrups and links of the first of said ladders, the juxtaposed stirrups and links of the second of said ladders.

KAREL SIP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number 4 1, 130

Name Date Philips Nov. 3, 1863 Wood 1 1 Jan. 24, 1865 Lane s -s- Oct. 30, 1877 Reiffenstein Aug. 13, 1895 FOREIGN PATENTS Country Date Austria .-s -'Feb. 25, 1910

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