|Publication number||US1789821 A|
|Publication date||Jan 20, 1931|
|Filing date||Nov 10, 1927|
|Priority date||Nov 10, 1927|
|Publication number||US 1789821 A, US 1789821A, US-A-1789821, US1789821 A, US1789821A|
|Inventors||Leffingwell William H|
|Original Assignee||Leffingwell William H|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (9), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Jan. 20, 1931. w. HJLEFFINGWELL 1,789,331
CHAIR Filed Nov. 10. 1927 2 Sheets-Sheet l gvwmwoz 6 y @513 Gb tomwiy Jan. 20, 1931. w. H. LEFFINGWELL C HA IR Filed Nov 10. 1927 2 Sheets-Sheet 2 awueutoz @Mowww Patented Jan. 20, 1931 I r r unrrsn rs ATENT new; i
WILLIAM-n. L'nrrmewnnt, or WEST-FIELD, New JERSEY oHAIR Application filed November 10,1927. Serial No. 232,215.
This invention relates to. an improved detweenthe buttocks and'thighs thus avoiding signin the art of chair buildin and parany pressure on the under side of the knees. ticularly those types of chairsadapted for the in the ordinary chair the seat is madefiof use in schools, oliices and factories, etc, such a depth thatthe user, in endeavoring to whereinsedentary occupations are required. sit with his back against the back of the 'It has long been known that incorrect seat chair, creates a pressure on the nerves and ingpositions cause numerous internal ailblood vesselsinthe popliteal region. Asthe ments, such as indigestion, constipation, imveins and nerves in this region (under the proper circulation of the blood and certain knee) are very near the surface any pressure 10 nerve diseases caused by undue pressure on oi whatever degree makes for a retarded ac- 6O '1 hours.
the nerves. Also improper breathing action tion, sometimes causing sciatica, neuritis and may be caused by acramped position of the a slowing up of the circulation. lungs,together with the usual fatigue one eX- Another object of my invention is to properiences after remaining seated tor a few vide a chair with a seat of just'sufiicient depth 9 to enable the user to sit comfortably without Here'tofore anumber of attempts have been producing a binding efiect under-the knee. made to correct this trouble by shaping chairs One of the causes of the body fatigue exto conform to the anatomy of the body; none perien'ced by those in sedentary occupations of which was entirely successful, due to the is that either no back rest is provided at all or fact that no two people or groups of people the one providedis practically useless, doing are exactly alike, and consequently a. chair more harm than good. In cases where there' made to fit one or a group of persons will not is a back rest it is oftentimes too high or too be anatomically correct for another person of low and no means is provided for adjusta different build. ing it to suit the back of'the user. Attempts I 95 One of the chief causes of internal body have been made, usually by inexperienced" ailments is the fact that the ordinary straight workers, to provide back rest of a shape back chair is uncomfortable to siton and, in to fit't'li'e body without first making a scienorder toease his position somewhat, the user 'tific studyto ascertain the sliape,position and unwittingly slides forward, thus casting the requirements of the human body. weight of his body on the' lower partof the These attempts have been successful only spine instead of onthe lower part otthe pelin a small degree for the reasons heretofore vis. In this position, the spine, instead of stated. Another object of my invention is being erect and straight, assumes a. curved to construct a'chair with scientificallydeposition cramping the organs of the abdosigned and positioned back support andone v men, and the lungs, and eventually resulting thatmay be readily and conveniently adjust- 35 in the body ailments hereinbefore mentioned. ed by the user while seated.
Also thesc in'correct sitting postures inter- A deeply curved shoulder rest also has the ferc with proper circulation'of the blood, and disadvantage of crouuling the shoulders forthereby induce a fatigue, which in no reward, causing a collapsed condition oi. the spect due to-the work done, whether its charchest aud thereifore another object of my inacter be mental or manual. vcution is to provide a shoulder support for A bje t. f m i ti n is to providea a ch air which will tend to'iiaitten the scapuchair for the offic worker, typisg-t l ph lac on. the back and provide the necessary operator, etc., that will preventthe body room for the proper functioning of the from slipping forward and hold it in erect 1;},6- I I upright position, thereby allowing the organs From the foregoing it will .be apparent that ofthe body to functionin their normal mannearly all, it not entirely all, of the nude ner. Another object of my invention is 'to sirable features of the ordinary chair have so shape the seat ofthe chair that the weight, been eliminated in my design for a chair disof the trunk is more evenly distributed beclosed herein. 'As a further object of my involition, I propose to make a chair in which the user may relax completely without falling into a slumped or other improper detrimental position.
To accomplish these and other objects of my invention, 1 provide a chair with a shorter seat than is customarily provided and one that is shaped to comfortably fit the body in the seated position. The front edge of the seat is recessed the proper amount required to give freedom to the movement of the legs and without interfering with the circulatory or nervous s terms. The rear portion of the seat is sufficiently recessed to give the correct posture position and also to maintain the body in a nm'inalhealthy erect position. To support the back and shoulders, I provide cross pieces mounted on upright supports located at the rear part of the seat; each upright support being so designed as to offer no obstruction to the arms or body. The shoulder support is curved slightly to fit the bony, without crowding or cramping the lungs; while the back support for the houbar region is curved slightly in two directions to more accurately conform to the contour of the occupants back. One of the important features of this invention is the mountin and functions of this back support. '10 overcome the disadvantages of prior devices having a fixed support for the lumbarregion I propose to mountthe sup port in a vertically adjustable manner and allow it to swing slightly about a horizontal axis. Thus, it will be seen that a chair incorporating this adjustable feature may be readily adapted to fit the back of any. person using it.
Other objects and advantages will be in part indicated in the follmving descriptions and in part rendered apparent therefrom in connection with the annexed drawings.
To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as a part of this disclosure and, in such drawings, like characters of reference denote corresponding parts throughout all the views, of which Figure 1 is-a front elevational view of a chair embodyingmy invention. Fig. 2 is a side elevation thereof showing, in dotted lines. a central vertical. section through the shoulder and back support to more clearly rate their shape and relative positions. G3 is a plan view of the chair seat and back supporting members showing their relative positions. one above the other and their curves. Figs. at, 5. 6.1", 8, and 9 are sectional views along es blit, 55, 66, 7*]: 8S, and 99. r ectively of Fig. 3 showing more clearly the degree of recessing given to the seat member. Fig. 10 is a fragmentary vertical sectional view through the back supporting members showing the shapes of their respective forward faces and the vertically adjustable swiveled mounting for the back support. Fig. 11 is a fragmentary front view of the chair back with parts thereof broken away to show more clearly the mounting of the lumbar rest. Fig. 12 is a. section through line 12-12 of Fig. 11, showing the notched plate for retaining the lumbar rest in position.
7 Referring more particularly to Figs. 1 and 2 this invention is disclosed as incorporated in a chair having a well known type of standard and, as this invention relates only to that part of a chair from the seat up, it is to be understood that any type or style of standard maybe used; the type shown in the drawings is for convenience of illustration only. The posture chair proper combines a deeply recessed seatmember 1, with two upright supports 2, which are scientifically shaped to more closely conform to the body and designed so as to be free of any obstructions to the arms or lmttocks.
Referring to Figs. 2 to 9 inclusive, it will be not-ed that the design of the seat member 1 presents a radical departure from the usual type of chair seat. The depth of the seat is preferably made considerably shorter than it is usually constructed to enable the occupant to sit comfortably thereon without sliding forward to gain thenecessary room for the bending of the leg at the knee joint. The front edge of the seat I propose to shape, as shown in Fig. 9, with a large downward curve removing that part of the seat which ordinarily creates a pressure on the underside of the knee of the occupant.
The rear portion of the'scat member 1 is formed with a deep bowl-shaped recess a as indicated in the sectional Fi s. 7, S and 9; the forward portion of which cooperates with the forwardly disposed longitudinal hump 71. to form the relatively steep incline'c. The incline 6 extends forwardly on either side of'the hump 72 and forms two shallow channels 8 properly contoured to fit the thighs of the user. It, therefore, becomes apparent that by reason of the contour of the surfaces 7', e, h and s on the seat member 1, a proper, accurate, form-fitting support is formed for the gluteofemora-l muscles of the user. I
The upright supports are preferably two in number for the reason to'be hereinafter stated, but it will be understood that any number of supports may be employed without departing from the spirit of this invention. As shown in Fig. 2, the upright supporting members are shown in a fixed position with relation to the floor member 1 of the chair and extend upwardly with a gradual inclination toward the rear. As is customary in the design of many office chairs,
the back supportis either pivoted, at a point near the seat member or the seat itself mounted on a pivot so as to permit the user to rock backward whenever he wishes. This feature of the usual office chair has the disadvantage of shifting the weight of the trunk of the body from the lower part of the pelvis to the spinal column and thus an incorrect habit of sitting posture results. The above notet faults are corrected in the invention disclosed herein; the proper angle of inclination of the back support with respect to the chair seat remains always the The supports 2 are separated as shown in Fig. 1, to allow ample room for the buttocks gluteal muscles, and thus it will be seen any person, w tether of large or small build, may comfortably sit all the way back in this type of chair and by so doing get the full benefit of the contour of the seat member and also of the back and shoulder rests.
At the upper end of the upright support ing' member 2, it has been found desirable to securely fix thereto a shoulder support 3 having the proper curves and shape, as indicated at a and b. The curve a is so designed as to afford a restful support for the shoulders of the user while working without cramping or interfering with the normal movements of the scapulm or arms.
Betweenthe shoulder support 3 and seat.
member 1, and within the plane of the up rightsupports 3, I mount a back supporting member 4 to support that part of the users back known as the lumbar region. A critical point in the design of posture chairs is the providing of an anatomically accurate support for this part of the back as it is in this region the worker tires first. As hereinbefore stated, supports have been made for this part of the back but have proved unsuccessful in that they were not adjustable to suit the back of the user and did not cooperate with the form of seat to bring about the desired result.
The support t in this improved posture chair is mounted as at 5 so as to permit vertical adjustment thereof and also pivoted as at- 6 so as to move with the body and afford a resting support in all positions. As shown in the drawings, the adjustable feature consists of the notched plates 7 attached to the upright supports and pivots 8 fixed to the member A. A recess 7* is formed in each of the upright members 2 to provide clearance for the pivots 8 when moved into any of the notches 7" formed in the plates 7. Obviously other suitable means for mounting the cross member 4.- so as to have a pivotal and vertical adjustment may be employed and therefore I do not limit myself to the precise construction shown in the drawings. An 1mportant feature is that the seat is formed of the back "tothe pos tion of the occupant brought about to overcome any'tendency of the body to-slip forward, while the support a braces that part especially needing support due area. The curve a in the verticalplane, more accurately fits the contour of the spinal col- 'umn and due to its pivotal movement the member 4 readily adaptsltself to fit the 0011-,
tour of the l acks of a larger number of-nsers The dotted line 'POSlijlOllS'Sl'lOWl'l'lll Fig. 10
serve to illustrate the pivotal mmen'ieint of the back 'rest member l, while the vertical adjustment thereof may be attained by moving the rest a forwardly out of one of the notches 7 of the plates 7 and raising or lowering as desired, all of which may be quickly and easily done by the person wl'iile seated.
It therefore becomes apparent that all the nnportant features of this type of chair cooperate together to bring about a eorrectposture sitting position and that the omission of one' or more creates a deleterious effect onthe 'user.
back ant shoulders, and conversely, produces an in urious result, or the lack of ample room for the buttocks tends to cause a forward movement of the body and consequently the.
user sits in anincorrect and harmful position.
Vithout further analysis, the foregoing will so fully reveal the gistof this in vention that others can, by applying current knowledge, readily adapt it for various i utilizations by retaining one or more of the features that, from the standpoint of the prior art, fairly constituteessential characteristics of either the generic or specific aspects of this invention and, therefor, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of. the following claims 2- Having thus revealed. this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States i l. A posture chair comprising a saddle For example, a recessed seat. member without the proper support forthe' the said lumbar rest being of a shape and size to form a support for the lower part of the back of said occupant, whereby the lumbar rest will be tilted to different positions by contact of the occupants back, the two contacting surfaces of the lumbar rest and shoulder rest with the back of the occupant being capable of being projected into different relative inclinations, one to the other, to enable the occupants back to be supported in erect position at both the shoulders and at a point adjacent the base of the spine, while permitting the occupant to flex the portion adjacent the base of the spine into different postures in order to overcome the normal tendency to shift the buttocks, thereby maintaining the buttocks in proper position on the seat.
2.111 a chair of the character described the combination of a seat with uprights projecting therefrom and spaced a substantial distance apart, said seat having a depression extending between the uprights, a hump formed on the forward part of said seat adjacent said depression, said hump being adapted to maintain the normal position of the buttocks within said depression, a fixed shoulder rest on said uprights, a lumbar rest pivot-ally mounted at a point adjacent the base of the spine and of a size and shape to afford a satisfactory support to the lower portion of the back of the occupant capable of being tilted by the occupants back while the shoulders are pressed against the shoulder rest to change the inclination of the surfaces of the lumbar rest and the shoulder rest in their relation, one to the other, whereby the occupants back will be properly supported both at the shoulders and near the base of the spine, said lumbar rest being automatically oscillated by any movement of the lower portion of the body, thereby permitting the occupant to flex the said portion of the bod into different positions counteracting any tendency to shift the buttocks out of correct position within said depression.
In witness whereof, I have hereunto subscribed my name.
lVILLIAM H. LEFFINGWELL-
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3102756 *||Jun 6, 1960||Sep 3, 1963||Strasser Georg||Multi-purpose furniture|
|US3463544 *||Apr 22, 1968||Aug 26, 1969||Edward Froelich||Orthopedic seat back|
|US4222607 *||Aug 23, 1978||Sep 16, 1980||The Dimmock Furniture Company Limited||Seating|
|US4634178 *||Dec 10, 1984||Jan 6, 1987||Carney Steven H||Adaptable seating device|
|US5297849 *||Oct 7, 1991||Mar 29, 1994||Chancellor Charles W||Vertically adjustable swivel support with lock for use with seating|
|US7393054 *||Nov 17, 2005||Jul 1, 2008||Lear Corporation||Self adjusting seatback system|
|US7857388||Jun 1, 2007||Dec 28, 2010||Steelcase Inc.||Seating unit with adjustable lumbar device|
|US20070108816 *||Nov 17, 2005||May 17, 2007||Lear Corporation||Self adjusting seatback system|
|US20080296945 *||Jun 1, 2007||Dec 4, 2008||Bedford Adam C||Seating unit with adjustable lumbar device|
|U.S. Classification||297/284.7, 297/353, 5/59.1|