WO1990009126A1

WO1990009126A1 - A chair with a back support

Info

Publication number: WO1990009126A1
Application number: PCT/DK1990/000035
Authority: WO
Inventors: Patrick Raymond
Original assignee: Labofa A/S
Priority date: 1989-02-15
Filing date: 1990-02-12
Publication date: 1990-08-23
Also published as: DK69089A; DK69089D0

Abstract

A chair comprising a seat (1) and a back support (2) accommodating supporting members for a person seated in the chair, the supporting effect of said members being variable, the right and the left halves of the seat as well as of the back support having individually at least one supporting member (8, 9, 10, 11), the element (8, 9) or the elements in either half of the seat (1) communicating effectively with the member (10, 11) or the members in the opposite half of the back support (2), and the members in the two halves of the seat and the back support, respectively, are effectively separated from each other.

Description

A chair with a back support.

The invention relates to a chair of the type stated in the preamble of claim 1.

Many forms of upholstery and the like are known, intended for distributing the pressure from a chair or another sitdown furniture in such a manner that, on one hand, it appears to be uniform and, on the other hand, it offers support to the contact surface exactly where needed between the chair and the seated person. With the view of obtaining a uniform pressure, use is made of springs, resilient material, such as foam rubber or foam plastic, bodies or bags filled more or less, with fluid or jelly. As base or backing frames, preferably having a suitable shape are used and for instance suspended so as to pivot about horizontal axes, such as known, in particular from office chair seats and backs.

In order to offer the intended support to a sitting person chairs designed and equipped according to the above mentioned technique require, however, that the person assumes a position symmetrical about the longitudinal median plane of the chair and the person proper.

As regards persons who are much seated, e.g. office staff, drivers of automobiles, trains, trucks and cranes, counter cashier staff and wheel chair users it is, however, tiring or inconvenient always to take up such a comparatively steady position.

It is therefore an object of the invention to provide a chair which by a given turning of the sitting person still offers the intended support.

This is obtained according to the invention by a chair of the above mentioned type characterized by the characteristic features stated in claim 1.

It is hereby obtained that if one half of the seat is weighed down in relation to its other half then the diagonally opposite half of the back support will be pushed forwards in relation to the back support half diagonally opposite to the other seat half, and vice versa.

According to a preferred embodiment the supporting members are constituted by flexible, gas-filled, baglike members, such as plastic bellows and the connections are of a flow-type, such as hose connections allowing gas to flow from the member or members in one half of the seat to the member or members in the other half of the back support, and vice versa. In such a chair the back support will turn about an axis located in the median plane of the chair and mainly parallel to the general plane of the back support proper in correspondence with the turning of the seat about a second axis located in the median plane of the chair and substantially parallel to the general plane of the seat proper. The degree of the turning of the back support in relation to the seat may be proportioned through the choice of the size and filling of the members.

According to a second embodiment of the invention the connection is of a mechanical or electromechanical type. In these cases the members consist e.g. of firm members movable perpendicular to the general plane of the back support and seat, respectively. The connections may for instance be provided by means of cables or push/pull rods and lever arms and the connections may be controlled electronically, thereby allowing the mutual movements of the seat and the back support to be controlled in a widely varying range of possibilities. Such a solution implies, however, that an electric energy source be accessible.

The invention will now be explained in detail by means of an example of implementation with reference to the schematical drawing the sole figure of which illustrates parts of an office chair according to the invention.

The chair illustrated in the drawing comprises a seat 1 and a back support 2. Moreover, the chair includes an undercarriage 3 with wheels.

Seat 1 as well as back support 2 have firm bottoms 4 and 5, resp., in the form of frames with appropriate, substantially plane shapes, as generally known in connection with office chairs. Above said firm bottoms there is an upholstery, not shown, beneath which supporting plates 6 and 7, resp., are mounted, made from a rigid or resilient material and shaped like the bottoms.

The supporting plates are shown transparent in the drawing, thereby also making the gas-filled plastic bellows 8, 9, 10, 11, 12 and 13 visible. With the end faces said bellows abut on the firm bottom 4 or 5 and the supporting plate 6 or 7, resp. The bellows are, moreover, pairwise associated by means of flexible plastic hoses 14, 15 and 16 so that one bellows 8 in the right half of seat 1 through hose 14 is flowingly connected with bellows 10 in the left half of back support 2, while the one bellows 9 in the left half of seat 1 through hose 15 is flowingly connected with bellows 11 in the right half of the back support 2, and the second bellows 12 in the right half of the seat through hose 16 is flowingly connected with the second bellows 13 in the left half of the seat.

The pairwise associated bellows 8, 10 and 9, 11, respectively, establish the above mentioned effective connection between seat 1 and back support 2, the effect consisting in that the back support "follows" the lateral tilting of the seat. Imagine thus a person sitting in or on the chair and leaning to the right from his symmetrical or central position, the right and the left side of supporting plate 6 of the seat will tilt downwards and upwards, respectively. This causes the gas pressure to increase in bellows 8 and to decrease in bellows 9, following which gas flows to bellows 10 and from bellows 11, respectively, in the back support, thereby tilting its supporting plate 7 on its substantially vertical centre axis so that its left side is being forced forwards while its right side is moving backwards. In the illustrated embodiment the tilting axis of supporting plate 7 extends through a hinge 18 between a projection 17 on said plate and bottom plate 5 of the back support.

Supporting plate 6 of the seat is further carried by two interconnected bellows 12 and 13 in the right and left seat halves, respectively. Said bellows 12 and 13 ensure a positive lifting of one side of the seat when the other side is pressed down by an asymmetrically sitting person.

By virtue of the above described arrangement a person sitting on the chair will experience that if he reaches out his hands for something to the left of him and thus leans a little in that direction, then the seat is tilted somewhat to the left. At the same time the back support follows the movement of the seat to a degree that is dependent on the mutual ratio of area between the end faces of the bellows in the back support and in the seat. This "follow"-action of the back support corresponds to the twisting the sitting person is spontaneously effecting of the upper part of his body upon his reaching out for something.

It will appear that the chair in this manner offers a better support upon reaching out in comparison with a general office chair.

Another case in which the mobility of the chair according to the invention is of benefit to the sitting person is, if he/she assumes a leaning-back, crosslegged position, thereby weighing more heavily down on one half of the seat, the upper part of the body being somewhat turned to the same side. Also in this case the chair will follow the somewhat slantingly seated person and offer an optimum support.

The effect of the above described chair is dependent on the "height" of the bellows in the seat and the back support. Due to the fact that a heavy per- son will compress the bellows more than a light person, two persons of different weight will not have the same advantage from the chair. This may, however, be compensated for by correcting the filling of gas into the bellows. This may be achieved in several ways, inter alia by mounting bellows, not shown, below the bottom of the seat which are flowingly communicating by hose connections with a respective one of the insulated pairs of bellows 8, 10; 9, 11; 12, 13 of seat 1 and back support 2 of the chair. Said supplementary bellows will be compressed when a person sits down on the chair and force more or less gas into the insulated pairs of bellows in dependence of the weight of the person.

Claims

P A T E N T C L A I M S

1. A chair comprising a seat (1) and a back support (2) accommodating supporting members for a person sitting in the chair, the supporting effect of said members being variable, characterized in that the right and the left halves of the seat as well as of the back support individually include at least one supporting member (8, 9, 10, 11), that the member (8, 9) or the members in either half of the seat (1) is/are in effective communication with the member (10, 11) or the members in the opposite half of the back support (2), and that the members in the two halves of the seat and back support, respectively, are effectively separated from each other.

2. A chair as claimed in claim 1, characterized in that the supporting members are constituted by flexible, gas-filled, baglike members (8, 9, 10, 11) and that the effective connection is constituted by conduits (14, 15) through which gas may flow from the member (8, 9) or the members in one half of the seat (1) to the member (10, 11) or the members in the other half of the back support (2), and vice versa.

3. A chair as claimed in claim 1, characterized in that the effective connection is of the mechanical or electro-mechanical type.

4. A chair as claimed in claim 2, characterized in one or more supplementary flexible, gas-filled, baglike members (12, 13) in the right half and left half of the seat (1), said supplementary members being flowingly interconnected and symmetrically disposed with respect to the longitudinal median plane of the chair.