EP1998648A1

EP1998648A1 - Chair with adjustable back support

Info

Publication number: EP1998648A1
Application number: EP07747565A
Authority: EP
Inventors: Jurek Buchacz
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-03-15
Filing date: 2007-03-14
Publication date: 2008-12-10
Also published as: WO2007105959A1; NO327509B1; NO20061211L; EP1998648A4

Abstract

A chair, particularly an office chair, comprising a seat part (2) and a back part (3) which can be adjusted in relation to the seat part, where the back part is equipped with a back support in the form of a fluid containing cushion device (4) where fluid by exerting pressure against an upper part of the cushion device is transferred to a lower part of same so that the lower part expands and provides support for the lower spine of a person (8) leaning backwards on the chair (1). The cushion device (4) comprises one only, upper air cushion (5) and at least one lower air cushion (6) where the upper and lower air cushions are connected via a channel (7) equipped with a valve device (9) for control regulation of the air transfer between the cushions (5, 6).

Description

Chair with adjustable back support

The invention relates to a chair particularly an office chair, comprising a seat part and a back part which can be tilted in relation to the seat part, in which the back part comprises a back support in the form of a fluid containing cushion device, where fluid by exerting pressure against an upper part of the cushion device is transferred to a lower part of the same, so that the lower part is expended and provides support for the lower part of the back to a person leaning backwards on the chair.

By using of office chairs having a back part which can be tilted in relation to the seat part, is often a problem that the back part, even if this is equipped with a lumbar support for the lower back, does not give the wished support for the lower back for use of the chair in that it will be a gap between the back support and the lower back when the user is leaning backwards in the chair beyond a certain tilting angle of the back part in relation to the seat part. Even if the lower back part port will provide a satisfactory support for some users, there will also be a problem in that it does not give the desired support for users of different heights.

A chair equipped with a cushion device of the initially mentioned type, is known from US 2005/0146195 Al . This known device comprises only one fluid containing cushion provided on the back part of a chair, where fluid by using pressure against an upper part of the cushion is shifted in the cushion from the upper to the lower region by lesser induced pressure and thus provides a passive, automatic adjusted support of the lumbar/lower back region of a user by tilting the back part.

A similar support device is known from FR 2 557 441.

The above mentioned known support devices provide a variable support similar to the support provided of a water bed, in that the form of the fluid containing cushion all the time will vary and adapt to the back position of a user. The support will thus be experienced as somewhat unstable and therefore less stable and well defined as desirable.

An object of the present invention is to provide a chair with a lower back support which in a simple and a confidential way can be adjusted to a desired, fixed size of a person sitting on the chair and where the lower back support at the same time can be adjusted suitable for the height of the person sitting on the chair.

In order to obtain the object the chair has been provided of the initially mentioned type which according to the present invention is characterised by the cushion device comprising an upper air cushion and at least one lower air cushion where the upper and lower cushions are mutually corrected via a chair equipped with a valve device for a controlled adjustment of the air transfer between the cushions. The present invention is further described in the following by means of exemplary embodiments and drawings, where

Fig. 1 shows a schematically a side view of a chair equipped with a first embodiment of support according to the invention,

Fig. 2 shows a similar view as Fig. 1, where the support device is adjusted for providing support of the lower back region of a person sitting on a chair,

Fig. 3 shows schematically a side view of a chair equipped with a second embodiment of a support device according to the invention,

Fig. 4 shows a similar view as Fig. 3, where the support device is adjusted for a suitable support of the lower back region of a relatively short person sitting on the chair, and

Fig. 5 shows a similar view as Fig. 4, where the support device is adapted to a relatively large person.

In Fig. 1 and 2 a chair 1 is schematically shown comprising the seat part 2 and a back part 3 where the back part can be tilted relative to the seat part. The chair is equipped with a lower back support consisting of cushion device 4 comprising an upper cushion 5 and lower cushion 6 where the upper and lower cushions are connected via a channel or conduit 7, such as a rubber hose, for air transfer between the cushions in accordance with the pressure load against the cushions. The upper cushion 5 has a somewhat larger volume than the lower cushion 6 and flatter and wider form than the latter. When a person 8 is sitting on the chair, leans backwards against the back part 3 and thus exert a pressure against the upper cushion 5, air will be transferred from the upper to the lower cushion so that this will expand much in the direction against lumber regions that the gap between the back part and the lower spine is filled and the lower spine gets comfortable support.

On the conduit 7 a valve 9 is connected for controlled regulation of the air transferred between the cushions. When the desired adjustment of the air cushions has been achieved and the valve 9 then will be closed, the cushions will obtain a term and well-designed size which is maintained in which a person in the chair moves relative to the cushions. The valve is connected to a suitable operating device (not shown), so that the valve easily can be opened and closed by a person sitting on the chair.

The cushions 5, 6 can be made of an elastic or non-elastic material. The cushion device 4 can entirely be positioned for instance low padded foam plate on the back part 3 and thus become an integrated part of the chair or it can be a separate unit releasable provided on the front side or the back part in a height above that is suitable for a person using the chair. Also the integrated embodiment cushion device is preferably mounted adjustable in height in relation to the seat part.

In Fig. 3-5 a second embodiment of a support device is shown schematically according to the invention. Fig. 3 shows a chair 11 comprising the seat part 12 and the back part 13 and which is equipped with a support device 14. The support device comprises an upper air cushion 15 which in the shown embodiment is connected to three lower air cushions 16, 17, 18 which, provided vertically by each other on the back part 13 below the upper air cushion. Each of the lower air cushions 16, 17, 18 is connected to the upper air cushion 15 via a main channel 19 and respective branch channels 20, 21, 22. On each of the branch channels it is a respective valve device 23, 24, 25 is connected for controlled adjustment of the air transfer between the cushions, in principle similar to the first embodiment. Said channels can comprise suitable conduits or rubber hoses.

The valves 23, 24, 25 are connected to a common operating device (not shown), so that the valves easily can be opened and closed by a person sitting on the chair. In a preferred embodiment the valve device is multi-valve for simultaneously opening and closing of all the channels between the lower cushion and the upper cushion.

As in the first embodiment the cushions 15, 16, 17, 18 can be made of an elastic or a non-elastic material. Contrary to the first embodiment the support device 14 in this embodiment is mounted on the back part 13 in a fixed height in relation to the seat part and will normally be mounted as an integrated part of the chair. As the lower part of the supported device consists several cushions (two or more), these will adapt to a correspondingly extended area of the back, including the lower spine region of a person sitting on the chair. This is illustrated in Fig. 4 and 5 where Fig. 4 shows a relatively small person 26 sitting on a chair 11 while Fig. 5 shows a relatively large person 27 sitting on the same or a similar chair. As would appear the lower cushions 16, 17, 18 in the adjustment phase will adapt a form that adapt to the lower spine area of the person sitting on the chair and thus provides the desired support without a necessary cited adjustment of the support device.

Claims

P a t e n t c l a i m s

1. A chair, particularly an office chair, comprising a seat part (2) and a back part (3) which can be tilted relative to the seat part, where the back part comprises a back support in the form of a fluid containing cushion device (4) where fluid by exerting pressure against an upper part (5) of the cushion device is transferred to lower part (6) of the same so that the lower part expands and provides support for the back spine of a person (8) leaning backwards on the chair, characterised in that the cushion device (4) comprising an upper air cushion (5) and at least one lower air cushion (6) where the upper and lower air cushions are connected via a channel (7) equipped with a valve device (9) for control regulation of the air transfer between the cushions (5, 6).

2. Chair according to claim 1, characterised in that the upper air cushion (5) is connected to a lower air cushion (6) via a channel (7) with associated valve (9), in that the cushion device (4) is adjustable in height relative to the seat part (2).

3. Chair according to claim 1, characterised in that the upper air cushion (15) is connected to several lower air cushions (16, 17, 18) provided vertically above each other on the back part (13), each lower cushion (16, 17, 18) are connected to the upper cushion (15) via a channel (19, 22) with associated valve device (20, 21, 22).

4. Chair according to claim 3, characterised in that the valve device is a multi- valve for simultaneously opening and closing of all channels (19-22) between the lower cushions (16-18) and the upper cushion (15).

5. Chair according to claim 3 or 4, characterised in that the cushion device (14) is mounted on the back part (13) with a fixed height in relation to the seat part (12).

6. Chair according to one of the preceding claims, characterised in that the cushion device (4, 14) is provided on the inside of a resilient back cushion on the back part (3, 13).

7. Chair according to one of the claims 1-5, characterised in that the cushion device (4) is provided at a separate unit releasable provided on a back cushion of the back part (3).