WO2005117652A1

WO2005117652A1 - A self-adjusting chair back

Info

Publication number: WO2005117652A1
Application number: PCT/YU2005/000016
Authority: WO
Inventors: Radmilo Eric
Original assignee: Radmilo Eric
Priority date: 2004-05-17
Filing date: 2005-05-16
Publication date: 2005-12-15
Also published as: EP1786293A1

Abstract

The present invention relates to a self-adjusting chair back consisting of two vertical sides VS. The two sides are forming a chair back with an anatomical profile in the way that the horizontal cross-section is concave in the complete height of the chair back, while the vertical cross-section is convex in the lumbal zone, and concave above this zone. Dependent on the sitting position (straight up or backward), and on the body dimensions of the user, the vertical sides VS of the chair back are bended backward and move apart, thus changing the vertical and horizontal profile of the chair back. The lumbal support remains in all sitting positions in a fixed position in respect to the chair construction. The sides VS are connected to the sit S or to the' chair construction with their rigid parts 1. Each of the vertical sides VS has a middle part 2 with inclined bending zones of decreased cross section in respect to parts 1, and with the height corresponding to the lumbal support. Above the parts 2 of each of the vertical side VS, there are parts 3 which are concave and rigid. In the variant I the parts 3 of the vertical sides VS are connected one to the other with the elastic bond 4. In the variant 11the parts 3 of the vertical sides VS are not connected, but there is an arch-shaped bended part of the arm-rest behind them.

Description

A self-adjusting chair back

Technical Field

The present invention is related to the field of furniture design and it concerns furniture with improved construction as regards enabling anatomical adjustment in sitting position. According to the International Patent classification, it may be grouped to classes A 47 C7/00, A 47 C7/40, or A 47 C7/46.

Technical Problem

This invention solves the problem of adjusting the chair back shape, or specifically its horizontal and vertical profile, to users of different body dimensions and in different sitting positions.

Background Art

To the best knowledge of the author, there is no patent or non-patent literature with similar solution of the self-adjusting chair back with adjustment of both horizontal and vertical profile.

Disclosure of the invention

The technical problem is solved with a self-adjusting chair back, which is the subject of this patent application.

The essence of the invention is that the chair back is fabricated consisting of two sides separated along the vertical line in the backbone zone. The vertical sides of the cantilever chair back have a fixed connection to the sit or the construction of the chair. The upper free ends of vertical sides are connected one to the other by an elastic bond, which is limiting the distance between the sides. The cross-section of the vertical sides change along their length which enables the change of the position of the upper parts of the sides (superior to the lumbal zone) and their adjustment to the sitting position. Such a chair back has a concave horizontal cross section along the whole its height, and the vertical cross section is convex in the lumbal zone, and concave above the lumbal zone. For the correct anatomical support of the back, it is necessary to provide a support in the lumbal zone and some part above it. In the upright sitting position, around 75% of the body weight is supported by the sit, and the chair back is bears a minimal weight. There are two reasons for a change in the sitting position: 1. Longer sitting in a same position makes tired certain muscles groups that are engaged in keeping the body in equilibrium. In the changing the sitting position, a user unconsciously engages another group of muscles. 2. The compression of the gluteus muscle in the upright sitting position lead to decreased blood circulation and a feeling of uncomfort, and the user is eliminating this feeling by moving a part of the weight to the chair back, and decreasing the weight supported by the sit. This need of a user for a time-to-time change of the sitting positions (upright - backward) leads to a need for a correct anatomical supports in each position of the different parts of the back - the lumbal zone and the zones above it. The described chair back enables the self-adjustment in these changes.

The described chair back is applicable both in chairs with fixed or adjustable sit height. In chairs with a fixed sit, when the user wants to move in the backward position, he/she would raise the shoulders zone or the body and moves it backwards, and the upper parts of the chair back sides bend backwards and apart, so the user rests in the new position between the sides. The result is increased weight (pressure) on the chair back and decreased pressure on the sit.

In chairs with adjustable sit height and the described chair back, the user changes the sitting position in the way that he/she moves the weight (pressure) from the sit to the chair back (in moving to the backward position) or vice versa (in moving to the upright position), balancing around the lumbar support, which maintains the same position in respect to the chair construction.

In majority of people, the lumbal support (center of the lumbal zone) is located in the zone of 22.9-25.4 cm above the sitting plane.

From the previous description it is clear that the self-adjusting chair back changes its shape under pressure, thus adjusting it to the users back anatomy, and moves back to the previous position when the pressure is removed.

The material for fabrication of the self-adjusting chair back could be any panel material with elastic properties, like plywood, plastics, metal, or a combination of such materials.

Brief description of the Drawings

The invention is described in detail in the following drawings:

Fig. 1 - is an axonometric view of the self-adjusting chair back, variant I; Fig. 2 - is an axonometric view of the self-adjusting chair back, variant II; Fig. 3 - is a side view of the self-adjusting chair back bended in the lumbal zone; Fig. 4 - is an axonometric view of the self-adjusting chair back, variant HI;

Detailed description of Invention

According to the presented drawings, the self-adjusting chair back is presented in the embodiment with two vertical sides VS that are attached with their fixed and rigid part 1 to the construction of the chair. Each of the sides VS has a middle part 2 (with the height corresponding to the lumbal support) having inclined bending zones. The decreased cross-section in the middle part 2 enables the bending of the sides in this zone and secures the fixed position of the lumbal support in respect to the chair construction. Above the middle part 2, each of the vertical sides VS has the part 3 which is concave and rigid.

In the variant I, the parts 3 of the vertical sides VS are connected one to the other by an elastic bond 4. In the variant U., the parts 3 of the vertical sides VS are not connected, but there is an arch shaped bended part of the chair construction or a part of the arm-rest 5 that restricts the exaggerated movement of the sides VS backwards.

The function of the elastic bond 4 and armrest 5 is to limit the exaggerated bending backwards of the vertical sides VS and their exaggerated distancing apart. According to the variant HI, vertical sides VS have only the parts 2, attached to the chair construction 6, and parts 3, as in variants I and π. The self-adjusting chair back functions in the following way:

In the fig. 3 a person is depicted (in dashed lines) sitting in the upright position. The chair is with adjustable sit height In this sitting position, the largest part of the persons weight is applied to the sit S, while there is minimal pressure (weight) applied on the chair back, and the vertical sides VS are minimally moved from their original (non pressed) position. When the user moves backward on the chair (changing the angle between the sitting and back plains), and increases the pressure on the parts 3 of the sides VS, the sides VS change their position by bending the parts 2 (drawn with a solid line). The upper zones of the parts 3 are moved backwards (around the horizontal axis) and their inner edges move apart (around the vertical axes), in the way that the user's back are embraced with parts 3 which are supporting now a larger weight force, thus decreasing the weight on the sit S. After relaxing the user places his back between the parts 3 in a new sitting position. The larger the weight (pressure) on the vertical sides VS, the parts 3 move further back and apart, adjusting themselves to the shape of the user's back and to the increased pressure. The same user will cause different bending of parts 3, depending on more or less backward position, while users of different body dimensions, in the same sitting position, will also cause different bending of parts 3. The limiters 4, 5 are used to restrict the exaggerated bending of parts 3. When the pressure on parts 3 stops, they move to the initial position.

The use of the described self-adjusting chair back is not limited to the described use, but can be applied to various uses where it is necessary to provide longer comfortable sitting.

Claims

Claims A self-adjusting chair back, according to variant L wherein the said chair back has two vertical sides VS of the chair back with their rigid parts 1 fixed as a cantilever to the sit S or the construction of the chair, the middle parts 2 have inclined bending zones of decreased cross section with the height corresponding to the lumbal support, and the parts 3 are rigid and connected one to the other by an elastic bond 4. A self-adjusting chair back, according to claim 1 and variant π, wherein the said chair back has an arch shaped bended part of the chair construction or a part of the arm-rest 5. A self-adjusting chair back, according to claims 1 and 2 and variant HI, wherein the middle parts 2 of the vertical sides VS are fixed directly to the construction of the chair 6.