US2471024A - Chair with tilting back and automatically shiftable seat - Google Patents

Description

May 24, 1949. R. A. CRAMER 2,471,024 CHAIR WITH TILTING BACK AND AUTOMATICALLY SHIFTABLE SEAT I Filed 001;. 4, 1946 5 Sheets-Sheet 1 I E I INVENTOR. J figz rAL [NAME/Q y 4, 1949. R. A. CRAMER T 2,471,024

7 CHAIR WITH TILTING BACK AND AUTOMATICALLY SHIFTABLE SEAT Filed Oct. 4, 1946 I 5 Sheets-Sheet 2 mmvrm RMYA. [RAM ER May 24, 1949.

R. A. CRAMER CHAIR WITH TILTI NG BACK AND AUTOMATICALLY SHIFTABLE SEAT Filed Oct. 4, 1946 3 Sheets-Sheet 3 will/Ill.-

INVENTOR.

Patented May 24, 1949 CHAIR WITH TILTIN G BACK AND AUTO- MATICALLY SHIFTABLE SEAT Roy A. Cramer, Kansas City, Mo.

Application October 4, 1946, Serial No. 701,320

19 Claims.

This invention relates to chairs and more particularly to improvements in posture chairs of the general type having automatically tiltable backs.

One of the objects of the present invention is to provide a novel posture chair construction which combines an automatically tiltable back and shiftable seat in such a manner that an exceedingly comfortable action is achieved when the chair is in use.

A further object of the invention is to provide a chair of the above type wherein, as the back is tilted rearwardly, the seat automatically moves forwardly, thus securing an easy and natural pivotal action of the upper and lower portions of the users body substantially about the hip joints.

Another object reside in th provision of a chair having a novel construction which insures that during tilting of the back, the seat will automatically shift forwardly and the chair back will automatically follow the movements of the users back, in order to eliminate all tendency toward objectionable back-rub.

A further object includes the novel feature of maintaining the correct balance of the chair and its occupant with respect to the chair base during all angles of tilt of the chair back.

Still another object resides in providing a chair of the foregoing character which includes in addition to the automatically tiltable back and shiftable seat, a construction which enables the seat to be initially adjusted forwardly or rearwardly with respect to the chair support or pedestal and independently of the back, this arrangement providing a ready adjustment to accommodate the chair to different size persons.

A still further object comprehends a novel chair construction including relatively few parts which are relatively simple in construction and which may be economically manufactured and assembled.

Other objects and features of the invention will appear more fully hereinafter from a consideration of the following detailed description when taken in connection with the accompanyin drawings wherein a preferred embodiment of the invention is illustrated. It is to be expressly understood however that the drawings are employed for purposes of illustration only, and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein similar reference characters refer to similar parts throughout the several views;

Fig. 1 is a'side view, partly in section, of a chair constructed in accordance with the present invention, and illustrating the normal position of the back and seat;

Fig. 2 is a view similar to Fig. 1, showing the position of the parts when the back is tilted and the seat shifted forwardly;

Fig. 3 is a plan view, Partly in section of the bottom of the seat and adjusting members associated therewith;

Fig. 4 is a partial sectional; view taken substantially along line 4--4 of Fig.3;

Fig. 5 is a plan view of the bottom of the chair plate;

Fig. 6 is a transverse sectional view taken substantially along line 5-6 of Fig. 5, and

Fig. 7 is a transverse sectional view taken substantially along line 1-1 of Fig. 5.

Referring more particularly to Figs. 1 and 2, a chair constructed in accordance with the principles of the present invention is illustrated therein as comprising a'base orsupporting pedestal I0 having a seat spider I 2 secured to the upper end thereof, the said spider being formed to support a cushioned seat It and a back I6, in a novel manner which will appear more fully hereinafter. It will be understood that the pedestal I0 is adapted to be supported by any suitable type of base, the arrangement being such that the pedestal and hence the height of the seat, may be adjusted vertically, in a conventional manner.

One of the dominant features of the present invention, as illustrated in Figs. 1 and 2 resides in the novel construction and cooperation of the seat spider 12, the seat I 4 and the chair back I6, the arrangement being such that as the back It automatically tilts from the position shown in Fig. 1 to the solid line position shown in Fig. 2, the seat It automatically shifts forwardly as illustratedin this latter figure. In addition to such forward shifting of the seat, it will be seen from Fig. 2, that the rear portion of the seat shifts downwardly a slight distance, this action being clear from an inspection of the normal position of the seat and back, shown in dotted lines, and the automatically adjusted position, shown in full lines, whichthe parts assume as the back is tilted rearwardly.

In use, the automatic movement of the parts, above referred .to, is achieved as the occupant presses the back 16 rearwardly with a predetermined efiort, the operation resulting is an exceedingly comfortable action accompanied by the entire elimination of back rub. If desired, the chair may be equipped with a pair of arm rests, one of which is shown at l9, and preferably the arm rests are carried by portions 2! and Zia, Fig. 3, of the tiltable back Hi, this arrangement further increasing the comfortable action when the chair iisin use. .It is'ialso preferred that the back 16 be prcvi'ded'wlth a cushioned back rest l8 which may automatically tilt about a horizontal axis in any suitable manner, such as for example, as showniinfmyaapplication Serial Number 690,498, filed August 1451946, for Chair back. The back rest may .also be adjustable vertically as by means of a'handwheel 20, in order that it may readily. be accommodated to the most comfortable position with relation to the back of the occupant.

In order to secure thesabove highly desirable results;-zandvreferring tbF-Eiis-fil and "4, "-the'-:back i6 is formed with an upstanding post :-l 1: for receiving thebacl-r rests, and allpair of: arms Y 22 and 24 which are spositioned beneath :the seat l4 .and' extend forwardlynon either side-of the pedestal Ill. As showni -the forwardextremities of 'the arms 22 and 24,- are :pivotally connected, as byr-means of aeshaft 2.6470 8. pair of forwardly extending arms 28 andr 3ll==-iomied*integrally with the-spider J2.- WithJsuch an arrangement, it will beaneadilysperceivedmthatltheback IB- may be tilted in the manner illustrated in Fig- 2, the arms 22 -and ztpivotingmpon the: shaft 26 and with respect .toethe' s'tationary. ( arms 28 and 30 of the'spiderl 2.

Novel means are provided by the invention for slidably mounting the :seat L4 .uponthe seatsupport including the' spider l2, and .one iofLthe important features "resides in associating the seat with'th'e' tilting "were 3l6iine'such manner as to secure the automatic forward 'sl'iiftin'g'of the seat as the back :16 tiltsitotheposition illustrated in full llnes..inFig."-'2l A'sfsh'o'wn', such means includes 'a'.,'.chann'el shaped adjusting member 32 havinga'paii' 'of spaced apartplates' 34 and 36 connected bya base'fportior'ii38, the .said plates beingfipivotal'ly"connected to'rearwardly' extending arm's ljll -an'd "l2 ofith'e Spider 1'2, as by. means of a "shaft "44. :Irr'a manner to. be'mcre'particularly referred to% hereinafter, the seat 'l l'is'supportedupon a plate 18* havinghpair 'ofde'pending brackets beans *fifl'secure'd -thereto, thelatter being'pivotally connected tothe' plates 34 and "36 as by'meansof' aw-rod 52 positioned above-and in substantial vertical alignment with-theshaft '44. The-"forwardportions"of"each"of the plates '34 and 36-a're respectively 'p'rbvidewwith cam'slots 54;'-one of which is""shown'- Fig: '4, 'and" within these slotsycam rdilfsbfi and are positioned, the latter being'carried by arrhs' H-and "24 of the back- -l6=in'-'any suitable mannergsuch'as by means ofstdb shafts'60: From' thisarrangement, it will ice-readily '-seen'= that 'a'sthe"back I 6-is' tilted; and the arms 22 ar'id -24"pivot*downwardly about the shaft 2'6',*the cooperatiori' betweenthe cam rollers 56 and "58'and' theslot ilwill cause'the adjusting member 32 to pivot inaclookwise direction "about the-shaft M2 -Su'chpiviotal' action 'of'member 32 causes the brackets 48"an-d 50;?plaite and seat [4 to *shiitdownwardly*andforwardly as "heretofore pointed-out in-connectionwith Fig. 2. such'shifting o'f-"the"se'at;"relative tathespider I 2; isreadily enabled by-providing the plate 46 with 'a' pair ofidepending "guide" channels 62, 64 which are positioned 'to'receive and guide rollers 4 66 and 68 respectively, carried by the ends of shaft 26.

In order to maintain the parts in the position shown in Figs. 1, 3 and 4, and to yieldingly resist the back-tilting and seat-shifting movements, the present invention provides a pair of expanding springs and 12 which are interposed between the base 33 of the adjusting member 32 and a crossehead I4 oper atively connected with the seat spider I2. More particularly, each of the springs in and 12 is provided with an internal support including a rod and sleeve construction 16,- While an'a'djustment of the tension of springs ill and 1.2 is secured by an adjusting wheel 13 having a part 80 threadedly engaging a brace 82 formed integrally with the arms 28 and of the spider. As th'ehand wheel i8 is adjusted to move the cross-head 14 toward the brace 82, the tension oi the springs 10 and I2 is increased and hence the force required to tilt the back l6 and shift the seat Ml is likewisedncreased Thus, desirablevariations in-"spri'ngtension may :becreadily secured bya simple adjustment, readilyaccessible at the forward part of the chair.

Means are provided to limit-the return-movement of the seat, when the back 'I G returns to the normal uprightposition, 1 and preferably such means -is so arranged as to be shock absorbing in character; As shown,:suchmeansiincludes stop flanges 84 and 8B, respectivelyz tormed' on the guide channels Bland 64, at-bl'ock :of'rubber 38 being preferably secured to the rearr'faces 'of'the flanges to engage the forward trends of the'asarms 22 "and '24 lastheseattisamoved rearwardly and-returned tonorm'alposition.

In addition to the foregoing novel features, the present invention also provides arconstruction whereby the horizontal position 'of't-he'seatwith respect to its 'supportingz-basean-d the'zback, may

be varied in' order to iwiden 'orrnarrowithe seat depth tosuitthezpa-rticular-zuserzi In the form of the inventionillustrated; seerFigs; 5; -6 and 7., such construction-includes an adjustable hand screw 90, which when adjusted-is-capableof-moving the seat 14 forwardly or rearwardlywith-v respect to the plate 46.

-Moi'-e-particularly, theseat 14 includes a-seat plate 92*havingapair of spaced apart guide rails 94 and 96 secured theretoandengagin-gthe'top adjacent opposite edges 'of the-plate 46. Spacer strips 98 and [00 are: secured tozthe rails '94 and 96 respectively, and asshown in Figs.- Band 7, additional guide rails li-fll-and I04 are respectively secured to the-strips 98 .andl-00.-over .a substantial part oi'the-rear portions of the strips to form enclosed guides fQrM sIidablyHsecuring "the. seat p1ate.92 to the plate '46. .A. bracket 1-06 is secured to the plate 46 many SuitabIeMmanner'and is provided With-a-depending par-tel threadedly engaging the hand .screw 90. .I-n.order tolshift the seat plate. 92,. as theshand screw isthreaded in or out with respect to the part "18, the hand screw carries suitable abutments or. stops which engage alug H0 secured .toithe. seat plate 92 as by screws I I2. In the, formishown, such stops include washers H4 andl [6 together withcotter pins H8 and I20, although it will be understood that any suitable type of stop may be used for the purpose of sliding the seat plate 92 with respect to the. plate 46 as the hand screw 90 is adjusted.

.From. the foregoing, it will be understoodthat to adapt the chair tozanyparticular .person, it is only necessary that the .person sit in the chair whereupon the depth ofthe seat and the vertical position of the back rest may be readily adjusted to the most comfortable positions. For example the first named adjustment may be secured by rotating the hand screw 98 in order to shift the seat plate 92 forwardly or rearwardly with respect to the plate 46 to correspondingly increase or decrease the depth of the seat. During such operation, the hand screw 6% is threaded into or out of the bracket 5&5 and the seat plate 92 is shifted through the cooperation between the stop washers H4 and H6 and the lug Hi3. When the seat shifts, the enclosed guides formed by the parts 94, 8'6 and 32 on the one hand and parts 85, 33 and 1M on the other slide along the opposite edges of the plate 58.

Following these initial adjustments, it is only necessary to adjust the tension of springs ill and 52 by operation of the hand wheel 18 in order to obtain the desired resistance to tilting of the back. It is here noted that due to the shape of the cam slots 54 with which the cam rollers 56 and 58 cooperate, the back lfi is normally maintained in an upright or posture position with a predetermined force which must be overcome by a predetermined pressure against the back rest before tilting of the back occurs. This will be clear when it is seen that the contour of the slot 54 at I22 is extended toward the left beneath the cam roller, see Fig. l, and hence an appreciable force must be exerted before the cam rollers 56 and 58 may be moved from the upper ends of the cam slots l, during forward pivoting of the adjusting member 32. If desired the contour at I22 may be so shaped as to provide an increased resistance before tilting action of the back may be secured, it being only necessary to curve the cam slots further to the left beneath the cam rollers at I22 as seen in Fig. 4.

In operation, the parts occupy the normal, upright or posture position illustrated in Figs. 1, 3 and l. Should the occupant exert the predetermined pressure sufficient to overcome the tension of springs 79 and E2, the back it may be tilted to the full line position shown in Fig. 2 whereupon the seat i l will be shifted forwardly as heretofore pointed out, such action being secured through the association of the adjusting member 32 with the cam rollers 58 and 55 carried by arms 22 and 2-4 of the hack and through the connection with the seat It by means of the brackets 4-8 and 5G and the shaft 52. Due to the concurrent movements of the back and seat, it will be understood that an exceedingly comfortable action is secured. In particular, it will be seen that as the back is tilted and the upper portion of the occupants body moves rearwardly of the pedestal iii, the forward shifting of the seat, carries the lower portion of the occupants body forwardly. Thus the center of weight will be maintained over the pedestal of the chair and any tendency toward unbalance, by reason of tilting of the back, is eliminated.

There has thus been provided by the present invention, a novel posture chair construction embodying a variety of advantageous features, all of which cooperate to increase the comfort of the occupant. For example, the tiltable back is so arranged with respect to the seat, as to automatically shift the latter forwardly as the back tilts rearwardly, thereby resulting in an easy, natural action on the part of the occupant. Such operation moreover increases the stability of the chair, since the center of weight is maintained over the pedestal at all times. A further desirable feature insures the elimination of all back rub during the tilting action, this being secured by the combined movements of the back and seat and the pivotal movement of the back rest.

While the invention has been shown and described herein with considerable particularity, it will be understood by those skilled in the art, that various changes and modifications thereof may be resorted to without departing from the spirit of the invention. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A chair comprising a support, a seat slidably mounted on said support, a back pivotally connected with the support beneath the seat so as to be capable of tilting movement, and means interconnecting the back and seat for moving the latter forwardly with respect to the support as the back is tilted rearwardly.

2. A chair comprising a supporting pedestal, a seat spider carried by the upper end of the pedestal and provided with a pair of forwardly extending arms, a seat slidably mounted on the spider, a back, means for pivotally connecting the back to said arms so as to be capable of tilting movement, and means interconnecting the back and seat for moving the latter forwardly with respect to the spider as the back is tilted rearwardly.

3. A chair comprising a support, a seat slidably mounted on said support, a back pivotally connected with the support beneath the seat so as to be capable of tilting movement, an operative connection between the back and seat for moving the latter forwardly with respect to the supportas the back is tilted rearwardly, and resilient means beneath the seat for normally maintaining the back in normal upright position and yieldingly resisting the tilting movement thereof.

4. A chair comprising a supporting pedestal, a seat spider carried by the upper end of the pedestal and provided with a pair of forwardly extending arms, a seat slidably mounted on the spider, a back, means for pivotally connecting the back to said arms at the forward ends thereof so as to be capable of tilting movement, means operatively connecting said spider, back and seat for moving the latter forwardly with respect to the spider as the back is tilted rearwardly, and resilient means beneath the seat for normally maintaining the back in normal upright position and yieldingly resisting the tilting movement thereof.

5. A chair comprising a support, a seat slidably mounted on said support, a back pivotally connected with the support beneath the seat so as to be capable of tilting movement, and means including an adjusting member pivotally connected with the support and the seat and operatively connected with the back for movingthe seat forwardly with respect to the support as the back is tilted rearwardly.

6. A chair comprising a supporting pedestal, a seat spider carried by the upper end of the pedestal and provided with a pair of forwardly extending arms, and a pair of rearwardly extending arms, a seat slidably mounted on the spider, a back, means for pivotally connecting the back to the forwardly extending arms so as to be capable of tilting movement, and means including an adjusting member pivotally connected with said rearwardly extending arms and the seat and operatively connected with the back for moving the seat forwardly with respect to the support as the back is tilted rearwardly.

'l. A chair comprising a supporting pedestal, a sea'tspider carried by the upper end of the pedesannual taland provided. with a pair of forwardlyextending arms,v and a. pair of rearwardly-extending arms, a seatslidably mounted 'onthespider, a back having a substantially upright part at the rear of the seat and a pair of arms positioned be.- neath the seat, means for pivotally connecting the back to the forwardly extending arms so that the back'is capable of tilting movement, an adjusting member pivotally connected with said rearwardly extending arms, means for pivotally connectingsaid adjusting member and seat, and means-carried by said back arms and operatively connected with said adjusting member for moving the latter about the first named pivotal connection tolmove the seat forwardly as the back is tilted rearwardlv;

8. A chair as defined in claim 7 including in addition, resilient means interposed between the adjusting member and said forwardly extending arms for normally maintaining the back in normovement, a seat positioned above said spider,

means including a pair of rollers carried by opposite ends of said shaft for supporting the seat for slidable movement with respect to the spider, and .means pivotally connected with said .spider and operatively connected with theseat andthe' arms of the back formoving the seat forwardly with respect to the spider as the back istilted rearwardly. v

10. A chair. comprising a supporting. pedestal, a seat spider carried by the upper end of the pedestal and provided. with apair of forwardly extending arms, a back having anuprightpart and a pair of arms arranged substantially parallel to the first named arms, means including a shaft pivotally connecting the forward ends ofall of said arms so that the back is capable-10f tilting movement, a seat positioned above said spider, means including a pair of rollers carried'by opposite ends of said shaft for supportingtheseat for slidable movement with respect to the spider; means for sliding the seat forwardly with respect to the spider upon rearward tilting movement-of the back, and resilient means beneath the seat for normally maintaining the back in normal upright .position and yieldingly resisting the tiltingmovement thereof. 2

11. .A chair comprising a supporting pedestal, a 'seat spider carried by the upper :end of the pedestal and provided with a pair of forwardly extending arms, a back having an. upright part and a pair of armsarranged substantiallyxparallel to the first named arms, means-including a. shaft pivotally connecting the forward ends of allrof said-arms so that the .back is capable of. tilting movement, a seat positioned abovesaid spider, means including a pair of rollers carried by-opposite ends of said shaft for supporting-the seat for slidable movement with respect tothe spider, an adjusting member pivotally connectedlwith said spider, means for pivotally connecting said adjusting member and seat,-and means carried by the arms of the back and operatively connected with said adjusting member for. moving the'latter about the first named pivotal connectionto. move the seatforwardly as theback istilted rearwardly;

12. A.:chair comprising a supporting pedestal, alseat spider carried by the upper end of the pedestal =and provided with a pair of forwardly extendingarms, a seat slidably mounted on the spider, aback, means for pivotally connecting the back-tosaid arms so as to be capable of tilting movement, .and means for moving the seat forwardly with respect to the spider as the back is tilted, rearwardly, said means including a plate pivotally connected with said spider, means pivotally connecting said plate to the seat, and means interconnecting the back and plate to move theplate about the first pivotal connection.

13. A chair comprising a supporting pedestal, a seat spider carried by the upper end of the pedestal and providedwith a pair of forwardly extending arms, a. seat slidably mounted on the spidena back, means for pivotally connecting the back to said arms so as to be capable of tilting movement, and means for moving the seat forwardly with respect to the spider as the back is tilted 'rearwardly, said means including an adjusting. member having a pair of spaced-apart paralleLplateseach formed with a cam slot, meansxfor pivotallyconnecting said plates with said; spider and seat at spaced apart points, and a-pair of cam rollers carried by said back and positioned withinsaid cam slots.

14. Archair comprising a support, a substantially horizontalplate slidably mounted on the support, a seatnslidably mounted on the plate, a backzzpivotally connected with the support beneath"the-,plate so-as to be capable of tilting movement,ymeans interconnecting the back, supportzandxplate for-moving the plate and seat mountedzthereon forwardly with respect to the support -asfithelback istilted rearwardly, and means for initially slidably adjusting. the position of: the-"seat with respectto the plate.

l5. Azo'hair; comprising asupport, a substantially. horizontalrplate slidablymounted on the support, a :seat slidably mounted on the plate, a back pivotally connected with the support beneath'the plate-so as to be capable of tilting movement, means interconnecting, the back, support and plate'for moving the, plate and seat mounted thereoniforwardly. with respect to the support as the:.back isi tilted rearwardly, and means comprisingzcooperating threaded members carried by said "seat andv plate respectively for initially adjusting. the position of the seat with respect to the plate.

. l6...A:; chair. comprising a supporting pedestal, a..zseat..'spider :carried by the upper end of the pedestaland provided with a pair of forwardly exten'd'mgrarms, a seatxslidably mounted on the spitier, a: :back', :means' for pivotally connecting the back to said .arms so as .to be capable of tilting movemenhandmeans for moving the seat forwardly/withrespect to the spider as the back is tiltedyrearwardly, saidv means including an adjusting member having a substantially vertically arranged :curved. cam slot, and a cam member carried by the back and cooperating with said slot.

- .17 A-Echair comprising a support having a seat mounted. thereon for sliding movement with respect;thereto,,a back for the chair, means for pivotallyuconnecting the back with the support so thattjhe back may tilt rearwardly with respect to theseat, resilient means normally acting to maintainlthe/rback in an upright position. and yieldinglyn-jresisting tilting movement thereof, a part pivotally-connected-with the support and the seat, andimeans including-a connection between said 9 10 back and said part for moving the latter about REFER]; E D the pivotal connection with the support to slide No S CITE the seat forwardly with respect to the support as The f01 1W1ng references are of Taco! d in the the back tilts rearwardly. me of thls patent? 18. A chair as set forth in claim 17 wherein 5 UNITED STATES PATENTS said connection includes a cam slot formed in said part and a member carried by the back and re- Number Name Date ceived in the slot June 19. A chair as set forth in claim 18 wherein the 798032 Gllson 1905 2,257,583 Wood Sept. 30 1941 reslllent means is positioned between the support 10 I and said part 2,420,745 Harmon May 20, 1947 ROY A. CRAMER.

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