US2538507A

US2538507A - Adjustable chair

Info

Publication number: US2538507A
Application number: US658270A
Authority: US
Inventors: Roy A Cramer
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-03-29
Filing date: 1946-03-29
Publication date: 1951-01-16
Anticipated expiration: 1968-01-16

Description

Jan. 16, 1951 R. A. CRAMER ADJUSTABLE CHAIR 3 Sheets-Sheet 1 Filed March 29, 1946 G i-torrlegs Jan. 16, 1951 R. A. CRAMER ADJUSTABLE CHAIR Filed March 29, 1946 5 Sheets-Sheet 2 f c 76 IT 12; I6- I 'Juvelzfol' Roy A.Cra11zer.

Jan. 16, 1951 R. A. CRAMER ADJUSTABLE CHAIR 5 Sheets-Sheet 5 Filed March 29, 1946 h N\\. wm .Q Q Q: 00w. $9 a Q nlu....

Grier-megs Patented Jan. 16,- 1951 umreo ;;srA"rEs PATENT OFFICE Roy A. 'Cramer, Kansas City, Mo.

Application March 29, 1946, s heme. 653,270

This invention relates to chairs and more par-' ticularly to improvements in chairs of the posture type adapted for oifice use, although it will be understood that improvements may be advantageously employed in chairs adapted for other uses.

Posture chairs of the general type to which this invention .relates have heretofore been provided with various types of adjustments in order that the positions ofthe seat and back rest may be readily varied tosecure a comfortable and proper posture position for the particular user of the chair. For example, the back rest has. been so arranged as "to be tiltable as well as adjustable vertically and horizontally with respect to the seat in an effort to arrange the back rest in a proper position. In making such adjustments in the prior chairs, the back rest support was first adjusted horizontally and vertically with respect to the seats after which the support 'for the back rest was locked in position. With such an arrangement, it has been round'that even with the back rest arranged for tilting movement about a horizontal pivot, the users back was subjected to a considerable amount of back rub as he leaned back in the chairs; repeated number of times. This o eration caused the 'users "garment, which was in contact with the back rest, to be stretched upwardly and subjected his back to an uncomfortable rubbing action.

In the prior chairs, it was also determined that when the back rest support was adjusted to move the back rest rearwardly or the :seat, the weight distribution of the user'of the chair was such that the 'chair" was'unstable with respect to its supportl For example, in'such' case, the center of gravity of the user oi the chair would be shifted torthe rear of the center of suppcrt'of the chair seatand the'chair would have a tendency to tilt baokwardly. This resulted in an undesirable unstable condition.

It is accordingly one of the objects of the pres ent invention to provide a posture chair which constituted as to avoid the disadvantages and objectionable features now present in chairs of this type.

Another object is to provide a novel posture chair construction which is provided with a back restso constructed as to entirely eliminate back rub? when the chair is in use.

:StiIl another object is" to provide a novel back restcons truction in'achair of the above type, whichisso arranged as to be automatically tilt able about a horizontal axis above the seat, and also arranged to be automatically adjustable vrthe seat, regardless of 11 Claims. (01. 155-115) tically of :the seat, these combined adjustments being automatically effected by the back or theuser and resulting in the complete elimination of back Tub.

A further object includes the provision of a floating back rest fora chair of the above character which automatically accommodates itself to the user's back, thus securing an exceedingly comfortable back support without back rub.

Still another object comprehends a posture chair construction wherein, with the chair in a proper weight distribution is maintained at all times, regardless of the adjustment of the backv rest and support therefor, toward or away from the seat, such an arrangement maintaining a high degree of stability of the chair under all condi-i tions of adjustment. Another object resides in the provision of a novel arrangement for 'ihtercormecting the back rest support, seat and seat support, in such a manner that as the back rest support is adjusted toward the seat, the latter automatically moves rearwardly with respect to the seat support andv toward the back rest support, and as the back rest support is adjusted away from the seat to accommodate a person of larger size, the seat automatically'moves forwardly with respect to the seat sup ort and awa from the back support, this construction being such as to automatically position the center of gravity of the user of the chair substantially over the center or support for the chair.

A further object includes a novel chair ctinstruction embodying the foregoing highly desirable and advantageous results which includes the adjustments h'eretofore's'tated and which rune tion to fully and comfortably compensate the chair to persons "of various sizes, the structure embodying relatively few parts and thus bein capable of being economically manufactured.

Other objects and novel features-ofgthe in vention will appear more fully hereinafter, from a consideration ofthe following detailed describ tion'whentaken in connection with the 'accompanying drawings wherein the invention is illustrated. It is to be expressly understood, however, that the drawingsare utilized for pur oses of illustration 01113 and are not designed as a den nition of the limits of the invention, reference being had for this latter purpose to the a ended claims I In the drawings, wherein similar reference charaotersrefer 'to'simila'r parts throughout the severaiviews:

the size of the person using.

Fig. 1 is a side view of a chair constructed in accordance with the principles of the present invention and illustrating in dotted lines, the various adjustments of the back rest, the back rest support and the seat;

Fig. 2 is a plan view of the under side of the seat of the chair shown in Fig. 1;

Fig. 3 is a partial sectional view taken along line 3'3 of Fig. 2;

Fig. 4 is a fragmentary perspective view of a part of the seat spider and bracket forthe back rest support;

Fig. 5 is a vertical sectional view of the back H rest and illustrates the construction for securing the combined automatic tilting and the vertical movement of the back rest; Fig. 6 is a front view of theback rest construction with the back rest cushion and supporting able in the base in any suitable manner in order to-adjustthe height of the seat. A back rest I6.

is adjustably secured to the upperportionof a back rest support I8, the latter being preferably formed of metal having someyieldability and being bent into an L-shaped form having an arm which is adjustably carried beneath'the seat I2 in a manner which will. appear more fully hereinafter; As shown, the seat I2 and the back rest I6 are provided with cushions, preferably of the latex foam type, and these are provided with suitable covers. which are maintained in position by any convenient arrangement.

One of the'features of the present invention resides in the provision of a novel construction for maintaining the stability of the chair, irrespective of the adjustment of the back rest support I 8 to accommodate the chair to different size persons. In the form of the invention illustrated, such feature comprises an arrangement which is operative to automatically shift the position of the seat I2 with respect to the pedestal I4, as the back rest support I8 is moved in a directiontoward and away from the seat. More particularly, and referring to Fig. 1, the full line position of the support I8 :and the seat I2 is such that the former is closelyadjacent the rear edge of the latter, and the center of the seat I2 as shown at 22, is slightly to the rear, of the center line 24 of the pedestal I4. It has been determined, that in the majority of cases whenthe parts are arranged in this manner, the center of gravity of the user of the chair, will substantially coincide with the center line 24 of the pedestal, in-

found to be desirable, and the support I8 is movedrearwardly toward the dotted line position, the present invention includes an'arrangement formoving the seat I2 forwardly with respect to the pedestal I4 toward the dotted line position shown, .in Fig. 1. It will thus be clear thatin such position, while the center 22 of the seat I2 is positioned forwardly of the center line 24 of the pedestal, as

shown in dotted lines, still the center of gravity of the user, will substantially coincide with the center 24 of the pedestal I4. In this manner, it will be appreciated that the stability of the chair under various positions of adjustment, will be materially increased.

Referring now to Fig. 2, in addition to Fig. 1, the foregoing novel construction includes an arrangement for interconnecting the arm 26 of the support I8, the seat I2 and thepedestal I4 in order to secure the advantageous results referred to above. More particularly, a seat spider 26 is secured to the upper end of the pedestal I4, and is provided with a plurality of outwardly extending arms .28, 30, 32 and 34, all of which may be arranged in a substantially horizontal plane. The seat I4 includes a metal seat plate 36 which is providedon its under side with a pair of

ribs

38 and 46 which are parallel to each other and which are capped with

flat plates

42 and 44. This construction thus provides a pair of guides or tracks for receiving the endsof the

arms

28, 30, 32 and 34 so that the seat plate 36 and the seat I4 are capable of substantially horizontal movement, fore and aft of the spider 26. In order to support the arm 26 of the back rest support I8, the seat plate is provided with a block 46 which includes a pair of

ways

48, 50 on which the arm 29 is adapted to slide. A suitable set screw 52, provided with a hand wheel 54 is threadedly received by a-portion of the spider 26 in order to secure the arm 20 in any desired position of adjustment along the

ways

48, 50.

In order to provide the above-mentioned .combined adjustment of the back rest support and seat, the spider 26 includes a projecting arm 56 Which carries a pivot pin 56 adapted to engage a lever 60 intermediate the ends of the latter. As shown, the outer end of the lever 60 is slotted at 62 and receives a stud or screw 64 which is secured to the seat plate 36. The inner end of the lever 66 on the other hand, may be slotted at 66 for the reception of a-stud or screw 68 carried by the armZIl. Preferably, the spider 26 is slotted at 16 to accommodate the inner end of the lever 66 which is positioned between the spider and the block 46. With such an arrangement it will be understood that in the full line position of the back rest support as'shown at I8a., and the full line position of the seat, as indicated at I2a,

rest support I8 be moved toward the seat I2, as

viewed in Fig. 2 to the position I8b, the lever 60 will rotate in a counter-clockwise direction about the fixed pivot 58 to a position indicated by the arrow 2 and cause the seat to be moved rearwardly to the position I2b. Also, :should the support! be moved away from the seat to the posi tion I80, the lever 60 will pivot to a position indicated by the arrow 3 while theseat will move forwardly and finally reach the position shown at I2c. Thus with such a construction, it will be seen that the-back rest support I8 and the seat I2 .are moved in opposite directions when it is desired to adiust the chair for different size persons. The adjustments are such, however, that the center of gravity of the user of the chair will, at all times, substantially coincide with the center line of the pedestal I4 and hence the stability of the chair will be maintained under all conditions. A further feature of the invention resides in a floating back rest: construction which is soarrang ed as to eliminatetback rub when the chair is in use. Referring more particularly to Figs. 1,

' 2. A chair comprising a base, a seat, means for adjustably supporting the seat on the base for substantially horizontal movement with respect thereto, a back rest, a support for the back rest, means for adjustably mounting, said support'on the seat, and means connecting the support, the seat and the base, for moving the seat in a direction opposite to the movement of the support when the latter is, moved to adjust the position of the back rest. v

. 3. A chair comprising a base, a seat, means for adjustablysupporting the seat on the base for substantially horizontal movement with respect thereto, a back rest, an L-shaped angle iron having one part supporting the back rest and the other part slidably mounted beneath theseat so that the back rest may be adjusted toward and away from the seat, and means interconnecting said other part, the seat and the base for movingthe seat in a direction opposite to the direction of movement of said other part.

4. In a chair having a base, a seat and aback rest, means for slidably mounting the seat on the base,-means for slidably mounting the back rest on theseat, and means interconnecting the sec-f ond means, the base and the seat for moving the latterin a direction opposite to the movement of the second means. I

5.- In a chair having. a base, rest, means for slidably -mounting the seat on the base-means for slidably mounting the back rest and the second means for moving the seat in a direction opposite to the movement of the second means. r

7. A chair comprising a base, a seat spider carried by the base, a seat, means for slidablymounting the seat on said spider so that the seat may move forwardly and rearwardly with respect to the base and spider, a back rest, a support having one part connected to the back rest and a second part slidably carried by the seat so that the support and back rest may move in and out with respect to the base, and means intercon: necting the second part, the seat and the spider for moving the seat forwardly as the second part is moved rearwardly, and for moving the seat rearwardly as the second part is moved for-v wardly. l

8. A chair as definedinclaim Twherein the interconnecting means comprises a lever pivotally mounted betweenits ends to the spider and having its opposite ends pivotally connected with the second part and the seat respectively.

a seat and aback 9.'A chair comprising a base, a pedestaLaseat:

spider carried by the pedestal, said spider being provided with a plurality of outwardly extending arms, a seat, means comprising a plurality of tracks carried by the seat for slidably mounting theseat on said arms, so that the seat may be moved forwardly and rearwardly with respect to the spider to adjust the center of the seat with respect to the pedestal, a back rest, means sup porting the back rest and slidably mounted beneath the seat, and means interconnecting the supporting means, the spider and the seat for moving the latter in opposite directions with respect to the direction of movement of the supporting means.

- 10. A chair comprising a base, a pedestal, a,

seat spider carried by the pedestal, said spider; be ng provided with a plurality of outwardly exr,

tending arms, a seat, means comprising a plura'L-j ityjof tracks carried by the seat for slidably mounting the'seat on said arms, so that theseat. maybe moved forwardly and rearwardly with respect to the spider, to adjust the center of the seat with respect to the pedestal, a back rest, an

L-shaped bracket supportingthe back rest and having a part slidably carried by the base so that, the back rest may be adjusted with respect to the" seat, and a lever connection between said part,- theseat and the spider for movingtheseat for-.

wardly when said part is moved rearwardly, and, for moving the seat rearwardly when said part is moved forwardly.

11". A chair comprising a base, a seat adjust ably mounted on the base for forward and rearward movement with respect thereto, a back rest, a support for said back rest, means for adjust ablyLi-fmounting said support on said base so that the support may be moved toward and away from.

the seat, and means interconnecting the support,-

seat-and base for moving the seat forwardly of. the base upon movement of the support'away from the seat and for moving the seat rearwardly I the support toward the seat. i ROY A. CRAMER REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Wood et a1. Dec; 3, 1946-