US2612939A - Tilting chair back - Google Patents

Description

DCL 7, 1952 J. s. BURDixcK 2,612,939

TILTING CHAIR BACK Filed May 15, 195o I?? vena/f' Oct. 7, 1952 J. S. BURDICK TILTING CHAIR' BACK 2 SHEETS-SHEET 2' Filed May 15, 1950 Patented Oct. 7, 1952 y :TII'ITING CHAIRQBACK Jahn' Smetana-North Muskgbh;'M1h.,xass`ignnr to The -Shawlvtfalkex' Company, 'Muskegom `Mich., a'corporation' of Michigan Applicationz yMay-.115, 1950,' SerittIxNo.y 162,025

l LThis `inventionrelates :,.to improvements in iopclaims. (cuss- 4156i however, it will bevconsidered thattthebackr thebacks of the greater number of its` or:cupa-nts` d regardless of its shape, form or dimensions.

N...The,principal object .ofthe invention isto pro,

vide ar simple form. `of tilting back unitrnounted Within they stationary chair back frame lso Qasto automatically tilt `or adjust itself. to `the proper angular position tontthe occupantsback. d d

Atturther object is togprovide'a `tilting .back

unit l which is ,capableA of `limited vertical adjust-.

ment ...relative to the lsiderails l of .a1stationary.

Y backV support,V to racconirnodate :persons of fdifferf ent,sizes,with `the `object. of making it possible iortheplaceinent of the convexity .'ofthefback unit .in `the correct ,tilt and vertical position, `for theiproperssupport of therlumbar 4:region of lthe occupants back.

@While the lnwentiodis particularly adapted f foruse .with oillcechairs, itcan be.` applied Vto any .design of ,chair .having `a stationary back traine` and .wherein the l tilting back `and its surroundingframe may be of simpleslattedfframe j construction `or 'of` luxuriously upholstered' con-` struction, y .1- Y l.. -A TheY invention. may. best, be understoodby lref-` erence to the accompanying d'rawings,.inwhich:`

Figure `14 is `a `View in side.d elevation .of la. chair made, inaccordance with4 my invention;

Figure 1; v

Figure ',3is anu enlarged :detailed `section `taken online ,3 3 of Figure f2; s 1

Figure 1-4 is enlarged detailed section taken vliandside of theftiltingback unitas shownlin Figureibut drawnto a larger scalefthantthe latter gure; d d d d l Figure 6 is a I partial .view similar: to .Figure 4,

Withparts in diierentjpositions Y "Referring now `to the `embodiment i, of` .my inv vention` illustrated in ,the drawings, .the same i is shown as-appliedato an ordinary straightfbackl chair; including .afseat I 0, front llegs t I I, I I reary dicated generally 'at l5;

In the formfshown her-emana ,back framemcludes .a top ran Is and upright l side rails i I 'I which extend downwardly to the `seat I 0. As shown herein, the

sidegrailsvll farellcontinuous with therear legs;

.A tilting bak'unit, indicated generally at la, is arranged to t `Within the open `area formed:

bythe top Irail I6 Vand-side rails .Iloftheback frame I5. Said tilting unit consistsof eaksecond frame having top andbottom frame members I8` and 20 4and side frame "members 2I.2I. vThe area `between said frame membersxis filled bya suitable supporting rweb, indicated l, `generally @at 22,- herein formed byfaplurality ,of uprightt slats 23 23. It will be understood,ihowevei-that the supportingweb 22 of themtilting` unit may 4beof various forms; as ,for instanceiitfmayiconsist of a vsolid backing. .or upholsteredrmaterial. `In any'case, the frontA of the supporting web .(22. of the` tilting unit is preferablyformedlslightlyconvexiin yverticalsectionifromftop to bottomtand slightly i concave in `,horizontal section,l so fas( to present an approximateform-iitting surfacezior` 'the `backof-the average. user- Y v i 'The tilting backpunit s I 8 is arranged? iorftilting as rawhole f about sa'transverse axis-intermediate its'topwand bottom framemembers I gaand 20,'` said 24,124. :each mounted ony one end of; an adjusting arm adjacentv theiinner sides of` thesidel rails ITtof-.Lthe lopen bacial frame i I 5. The oppositeeend of @they two adjustingfarxns25, 25,are mounted on bolts 26,26 whicnjlhewe4 threaded engagement in :trunnions 21, 2.1 :suitably "fixed to ithevinnen facesfof the uprightsiderails IT. `'I'heendsy of the. adjusting arms" Aditiwengage :the proximate faces of `the :'trunnons 21 withfsuitable 4friction lock 'devices 1 for holding each'arxn 15 randttrun.- nion 2l Aagainst'*relative movement inivarious' adl- .iusted positions. 'In the form 'shown herein.. said friction lock devices 4consist offserrated,'finl-` tertting teeth'28 Vand' 29 on'the `arms 25"a'nd trun'nion 21, respectively. Sai'dlteeth holdfeach vadjusting arm; infamy desired angular relation to the adjacent trunnion 2l when tlieboltZIi` is tightened. l l d In the` form shown herein, a pair fof jL`-shape`d brackets 3U, 30 connect the Vouter ends of .the pivot pins.24,.24.to the, rearfaee ofthesiciejfratxie` membersll, 2| ofthe tilting'back-unitI"B.,Fricf tionwashers 3I, v3| may be interposedlhetween the adjacent. `faces of the L-shape'd brackets 13D andthe adjusting yarm v2li, .andspring .v'vasherfs'` 32, ,32- may be. interposed between the outer heads l the l.-shaped 1 .brackets 24a of `pivot pins `2.4- and 30 (see Fgurez), i

EAs-'will be seen in` Figures 1 andzfthe 21, 21 and the adjusting arms 25, 25 connected thereto are preferably disposed nearer the bottom than the top of the tilting unit I8, so that a relatively free tilting movement of the unit I8 is permitted about the axis defined by the pivot pins 24, 24approximately atthe level of., the small of the back oftheavera'ge'occupant when seated in the chair in upright position. The

arms 25, 25, however, can be adjusted to various angles with respect to the trunnions 21, 21 soA as to shift the relatively free pivotal movement of the tilting unit into a slightlyhigher.orlower position, as desired, to accommodate theunitf v to persons of different lengths of torso.' L It will be observed further that the adjustment accommodated to the back of the occupant as f the arms 25, 25 relative to vthe trunnions 21,

21 will cause a rearward movement of the axis of when the arms 25 are swung either upwardly or downwardly with respect toa forward, generally horizontal position of saidf arms. This vtype of adjustment affordsA a stillgreater latitude of adjusting movement of the back unit with respect to the chair as a whole, tosatisfy the preference of the'per'so'n who usually occupies the chair.

` The trunnions 21, 21are provided with inward-'- ly. 'extending stop members 21a, 21d in position to: Vlimitthe angular and vertical adjustment of fthe lposition' ofA the -latter may be changed from ltimev to time. 15.

l Moreover, the axis of tilting movement of the back unit I8`ca`n be raised or lowered within cer- A tainlimits by readjusting the arms 25, 25 into relatively free tilting movement of the back unitv the arms 25 with respect to'sai'd trunnions so that the axis of relatively f ree pivoting movement of the tilting yback unit defined by pivot pins`V 24 is' maintained in advance of the axis about which the arms 25`r'are adjusted relative to the trunnions 21. Accordingly, `in all permissible positions'bf vertical'adjustment of the tilting back unit 18, the upright side frame members 2| of said v'tiltingback' unit are normally maintained in position well forwardly of and along the front aGesCf-the proximatestationary side rails I1 of the chairadjacent the'trunnions 21, as indicated in Figures l, 3 and 4'.

Rearward movement ofthe top 'of the 'tilting unit I8 -is limited in all positions of vertical adjustment of arm 25by engagement with a vertically disposed stop member33, herein consisting' of a' Slat-34 connected and extended between the rear lface of the upper rail I6' of the stationary back frame and a horizontal r'ail 35 connecting `tl'ieside rails I1,` I1 of the stationary chair frame,

frame includes a top yrail I6, the upper end of the vertical back stop member is preferably arranged sothat the front face of theupper frame meinber I9 of the tilting unit cannot swing rearwardly beyond the front face of said top rail I6, re-

gardless of the vertical position of adjustment of the tilting unit as a whole.

The use and operation of the device above described is as follows:

The tilting back unit Iuis free to accon'imodateV itself automatically. to the backs of occupants of i varying builds by tilting on the axis defined by the pivot pins 24, 24, merely by the pressure nor-v mally exerted against the chair back,` in whatever, seating position the occupant happens to assume in the chair. Since the back unit extends above and below its intermediate tilting axis with its major portion'above said axis, it will be tilted different angular positions where they will Ibe maintained by tightening the bolts 26. In all positionsl of :such vertical adjustment, the side frame members `2l of the tilting unit will be( disposed well forwardly Aof the 'adjacent side rails I1 o f the stationary back frame sov that the o ccupants back does not come intocontact' with the stationary side rails I1jat any time., Furthermore, the front' face ofthe topframe member I9'of the tilting unit cannot swingrearwardly'of the'front face of the adjacent topfrail I6-of the'stationary back frame. This arrangement eliminates any possibility of discomfort to the occupant during relatively freej tilting movements of the back unit I8, which otherwise might cause a portion of the occupants `back or head to bel brought suddenly into contact withftlienside y top rails of the stationary `back'frax'ne.

. When the axis of tilting'movement 'of the y'bac'lc' unit is properly adjustedverticallyjso'as to bel substantially atthe' level of the smallof `the back of the user, the 'unit can bev tilted automatically and relatively freely in either direction against slight frictional resistance, to' readjust itself to the most comfortable positionffor vvtl'ieoccupant'.'A The improved back structure is extremely simple in form and, in particular; retains the gen-l eral appearance of a 'conventional chair, since the trunnions and vertical adjusting arms are disposedbetween the upright side` railsOf the back frame, so las to be practically invisible from front andsides of the chair.' f i Although I havev shown and' described [certain embodiments of my invention, it will 4be understood that I'do not wish to be limited to theexact construction shown and de scribed, but thatvvarious changes and modifications may bemade withoutdepartment from the spiritand scope of the invention as denedin the' appended claimsl'V wenn: i .p j r i l. In a chair having a seat vand a substantially open back frame dened by'continuous top and side; rails, avv backunit pivotally mountedin said` open back frame for tilting movement on a transverse axis intermediate the top and bottom'of said unit and approximately at the level 0f the small of the back of the average adult occupant, said back unit substantially filling said open back frame'to form thebackrestvof said-chair, the major portion 'of said unit being disposed above said axis to permit 'reverselyv tiltable adjustment bypressure of the .occupants back above or below said axis,` the pivotal supportforsaid backunit comprising a pair of trunnions fixed to the'side' rails of said open back frame `and between which trunnions the back unit has limited relatively free tilting adjustment. said trunnions including arms", each having one of their ends adjustable'on horizontal axes to varying fixedV angular positions relative to said back frame, and the other end of each of said arms having the adjacent side of said back unit pivotally mounted thereon for tilting movement relative to said arms, and for vertical bodily adjustment relative to said back frame.

2. A chair structure in accordance with claim l,

'wherein stop means are provided on the back frame for limiting the tilting movement of said back unit with the side margins of said unit disposed in the front of the side rails of said open back frame in all permissible positions of tilting movement and vertical adjustment of said back unit. i

3. A chair structure in accordance with claim 2, wherein the stop means also limits the tilting movement of the upper margin of said back unit so that it does not pass rearwardly of the front surface of the adjacent top rail of the back frame in all permissible positions of tilting and vertical adjustment of said back unit.

4. A chair structure in accordance with claim 3, wherein the trunnions and adjustable arms are mounted on the inner faces of the side rails of said back frame and rearwardly of the lateral margins of said back unit.

5. In a chair having a seat and a substantially open back rest support including stationary upright side rails, a pair of rearwardly projecting trunnions mounted on said side rails substantially at the level of the small of the back of an average adult occupant, said trunnions havinggenerally forwardly extending arms pivotally adjustable on horizontal axes to varying fixed angular positions relative to said trunnions and forwardly thereof, a back unit pivotally mounted intermediate its top and bottom for relatively free tilting movement on the ends of said arms to form the back rest of said chair, said back unit being vertically adjustable within said open back rest support by varying the angular positions of said arms relative to said trunnions.

6. A chair structure in accordance with claim 5, wherein stop means are provided for limiting the angular adjustment of said arms relative to said trunnions so as to maintain the front face of said back unit along the side margins thereof in front of the side rails of said back rest in all permissible positions of tilting movement and vertical adjustment of said back unit relative to said back frame.

7. A chair structure in accordance with claim 6, wherein the stop means are fixed on said trunnions and extend into position to be engaged by said arms at the limit of angular adjustment of the latter relative to said trunnions.

8. In a chair having a seat and a substantially open back frame defined by continuous top and side rails, a pair of rearwardly extending trunnions mounted on said side rails having armsv pivotally adjustable on horizontal axes to varying fixed angular positions relative to said trunnions, a back unit pivotally mounted intermediate its top and bottom and approximately at the level of the small of the back of an average adult occupant for relatively free tilting movement on the ends of said arms, said back unit being vertically adjustable within said open back frame by varying the angular positions of said arms relative tosaid trunnions, said arms normally extending forwardly of their axes on said trunnions and being pivoted to the lateral margins of said back unit rearwardly of the latter.

9. A chair structure in accordance with claim 8,

v wherein stop means are provided for limiting the angular adjustment of said arms relative to said trunnions so as to prevent the front face of said back unit along the upper and side margins thereof, from passing rearwardly of the vtop and side rails, respectively, of said open back frame, in all permissible positions of tilting movement of said back unit relative to said arms.

10. In a chair having a seat and a back rest support including stationary upright side rails, a

pair of rearwardly extending trunnions mounted on said side rails having forwardly projecting arms pivotally adjustable on horizontal axes disposed approximately at the level of the small of the back of an average adult occupant to vary the forward angle of said arms relative to said trunnions, a back unit pivotally mounted for relatively free tilting movement on the ends; of said arms to form the back rest of said chair between said upright side rails, and said back unit being bodily adjustable vertically between said side rails by the angular adjustment of said arms.

JOHN S. BURDICK.

REFERENCES CITED The following references are of record in the

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