US 3512835 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
iMay19, 1970 Ffpwf'ono 3,512 835 Filed April '22, 1968 CHAIR I: 2 SheetS Sfiet 1 Fig; 1
H Inventor- FI' F2 0 t 0 t t o GLLJuJoLg rromwess United States Patent 01 hoe 3,512,835 Patented May 19, 1970 3,512,835 CHAIR Fritz Fltitotto, Friedrichsdorf, Germany, assignor to Fritz Fliitotto Friedrichsdorfer Schulmobelfabrik und Sagewerk, Westphalia, Germany, a firm of Germany Filed Apr. 22, 1968, Ser. No. 723,336 Int. Cl. A47e 7/16 U.S. Cl. 297-458 1 Claim ABSTRACT OF THE DISCLOSURE A chair, preferably a school chair, with a single piece made of a pressed material and forming the seat and the back, having an outwardly curving lower back portion connected 'with a central portion, the chair being characterized by an elongated seat surface with a slightly projecting central section and a curved recessed portion, the seat surface being followed by a strongly outwardly bent lower back portion the top of which is inclined and extends toward the lower portion which is V-shaped when viewed from the front and curved when viewed from the top with a slight recess in the middle, while the curved upper back portion has considerably wider sides and is curved for supporting the lumbar section of the spine in its upper section and the breast section of the spine in its lower section.
This invention relates to a piece of furniture and refers more particularly to a chair preferably intended for use by pupils in schools. Various types of chair seats are known or have been suggested the shape of which has the purpose to provide a support for the seated person, namely, to fix and to support in the seated position his spine and his pelvis which is in an unstable balance. The correct support of the body of a seated person depends upon the fact as to whether that person bends forwardly, sits straight or bends excessively rearwardly while sitting on the chair. These different sitting positions require different supports to elfec' tively hold the body in the seating position and avoid inuries.
The present invention is based in part on the consideration that a pupil in school usually assumes two different seating positions. The first position, wherein the pelvis is shifted rearwardly and the upper part of the body is slightly bent forwardly while the arms are supported, in which the pupil reads or writes is hereinafter described as the writing position. The second position, in which the pelvis is slightly shifted forwardly and the back leans against the back of the chair and is usually straight but is inclined slightly rearwardly, is hereinafter described as the listening position.
An object of the present invention is the provision of a chair the seat of which will supply an effective support in the listening as well as the writing positions, whereby it is necessary that the chair should not constitute a corset but should retain its supporting and holding functions even when the pupil, for example, sits sidewise on the chair.
Other objects of the present invention will become apparent in the course of the following specification.
In the accomplishment of the objectives of the present invention it was found advantageous to provide a chair, preferably a school chair, having a one piece section of pressed material constituting the seat and the back with a lower back portion which is strongly bent rearwardly and which is a continuation of a long seat area with a slightly forwardly extending central area and a curved extension. The lower portion of the back part has an upper section inclined corresponding to the position of the s sacrum of a pupil in the writing position and extending to a central section which is V-shaped when seen from above and is curved when seen from the top with a small recess in the middle. From this part extends a curved upper back part which also extends widely to the sides for supporting the upper part of the lumbar section of the spine as well as the lower part of the breast section of the spine in the listening position.
A chair seat constructed in accordance with the combination of the above-stated features, which constitutes the present invention, provides a most efiective support for the various parts of the human body both in the listening and in the writing positions.
It is well known that in the listening position the pelvis is moved forwardly and tips rearwardly upon its slide portion. A part of the rear bending of the lumbar section is then balanced. In this position human muscles must perform a great deal of work to prevent the body from falling rearwardly unless the body is provided with a support at the best possible location, which is in the range of the lumbar section as well as in the lower part of the breast section of the spine.
In accordance with the present invention, the central section is V-shaped and extends deeply downwardly to support the os sacrum. The end of the V is consequently located, for example, about 18 cm. above the seat surface if a school chair having size No. 4 is to be considered. The distance is proportionally smaller for chairs of smaller sizes. From there on the upper part of the back extends upwardly with corresponding inclination for the support of the breast section and the lumbar section of the spine in the listening position. The edges of the upper section of the back extend sidewise to a great extent to provide a truly all inclusive support. A long seat surface permits the forward movement of the pelvis, whereby the slightly upstanding central curvature provides a certain support.
The V-shaped central section has the V-shaped when seen from the front as well as when seen from the top, whereby the legs of the V are curved and a recess opposed to the curves is located at the juncture of the V.
As is known, the pelvis is shifted rearwardly in the writing position. Then it tips upon its slide portion from its rearwardly inclined position to a middle position. The entire spine is then moved forwardly and the lumbar section is straightened at the same time. To provide the best possible support for the human body in this position as well, the lower back portion is strongly curved rearwardly, so that the pelvis can be shifted rearwardly. This makes it possible to support the 0s sacrum of the seated person by the central portion, particularly by the deeply curved middle thereof.
As opposed to the buckling of the back of prior art constructions, the V-shaped central portion of the present invention, which is provided with a downwardly extending support within the range of 0s sacrum, makes it possible to hold the pelvis, thereby relieving the holding muscles. Furthermore, this construction avoids edge pressure which is most uncomfortable and which is caused by the prior art buckling.
The present invention provides in this manner a most effective freeing of muscles serving to 'hold the pelvis. It is important, however, that the lower back portion should have sulficient seat depth to make possible a subsequent rear shifting of the pelvis or of the posterior.
The curved part of the seat surface serves to fix the pelvis, particularly in the writing position, taking into consideration the anatomic form of the pelvis and of the ischium and the unstable balance.
Practical experience has demonstrated already that school chairs of the type of the present invention prevent early tiredness and protect their users from improper posture.
-In order to enable a chair of the present invention to be fully effective, it is necessary to make it in different sizes to correspond to the sizes of the human body.
The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example, a preferred embodiment of the inventive idea.
In the drawings:
FIG. 1 is the front view of a seat of a chair constructed in accordance with the principles of the present invention. FIG. 2 is a perspective view of the seat of FIG. 1.
FIG. 3 is a top view of the seat of FIG. 1.
FIG. 4 is a diagrammatic side view illustrating the supporting action of the chain of the present invention in the writing position.
FIG. 5 is similar to FIG. 4 but illustrates the supporting action of the chair in the listening position.
In FIG. 1 the line is used to illustrate the V-shape of the central section in conformity with the present invention. Supplementary thereto the line 21 of the top view of FIG. 3 shows that the central section 5 has a V-shape when viewed from the top as well, and that there is a recess 22 at the connection of the legs of the V.
As best shown in FIG. 2, further features of the chair of the present invention include a substantially long seat to provide for the sitting person a sufficient supporting surface for the posterior and the upper parts of the thighs in the listening position with the forwardly moved pelvis. 'In this position, a slightly upwardly extending central part 2 provides a certain hold at the front seat end, to prevent the sitting person from shifting too far forwardly while changing from a writing position to a listening position. A downwardly extending curved section 23 provides an additional fixing of the pelvis, particularly in the writing position, while taking into consideration the anatomic shape of the pelvis and of the ischium and the unstable balance.
The seat 1 passes over an extensive curve 3 into the back 4 which is divided into an upper seat portion 6 and a lower seat section 7 by means of the above described deeply bent section 5. As already stated, the distance between the deeply lying seat surface and the crest of the section 5 should amount, for example, to about 18 cm. for a school chair size 4. This distance is proportionately diminshed for school chairs of smaller sizes.
The lower back portion 7 has side recesses 8 which extend in the shape of curves from the seat surface 1 to the section 5.
As is best illustrated in the diagrammatic representation of the chair of the present invention for the listening position shown in FIG. 5, the upper back part 6 is then used for supporting the back. The back part 6 is curved at the edges 10 to provide a side support as well.
Furthermore, the part 6 is inclined rearwardly with slight inner curvature to support the lumber spine section and the lower breast section of the seated person in the listening position. The line 13 indicates the outline of the contacting surface of the sitting person in the listening position. There can be no edge pressure since the upper edge 14 of the back 4 as well as the edge 15 of the seat surface 1 are bent inwardly.
The line 16 indicates the outline of the contacting surface of a sitting person in the writing position in FIG. 4. A comparison with the listening position shows that the posterior was shifted into the strong outer curvature 3 of the lower back portion 7. This makes it possible to bring the 05 sacrum into its supporting range. The supporting range is formed by the V-shape of the section, as seen from the front, with a deeply located crest.
These features of the chair seat of the present invention provide for the two positions which a pupil usually as sumes while learning, namely, for the writing position and the listening position, an effective support for his body by the seat surface and the back of the chair. This greatly relieves the muscles holding the human body. The attention of the sitting pupil is thus not disturbed and damages to his posture are avoided.
It is apparent that the example described above has been given solely by way of illustration and is capable of many variations and modifications within the scope of the present invention.
What is claimed is:
1. A chair, particularly for schools, comprising a single member constituting a seat, a back and a central portion, said seat consisting of an elongated forwardly extending portion, said central portion consisting of a part which is sharply curved inwardly and is rising toward the back, said back being V-shaped when viewed from the front, said V-shaped portion being also spaced from the top of said back and having its deepest point at the os sacrum of a user and rising toward his pelvis curves, said back being curved when viewed from the top and having a curvature adapted to the os sacrum of the user in the middle of the deepest point of the V.
References Cited UNITED STATES PATENTS CASMIR A. NUNBERG, Primary Examiner U.S. Cl. X.R. 297457