EP2210528B1 - Work chair with air-cushioned support areas - Google Patents

Abstract

The work chair has air-padded support surfaces, in which a self-inflating air pad (3,9) is arranged within a backrest (1). A changeable dynamic sitting position of the user, derived on the backrest or a seat surface, directly leads a change of inflating condition depending on the position of the user on the work chair.

Description

The invention relates to a work chair with air-cushioned support surfaces according to the preamble of patent claim 1.

Such a work chair is, for example, with the subject of DE 198 27 683 C1 known. In this known arrangement, a self-inflating air cushion is arranged in the backrest part of a work chair, which is divided into two separate sections.

The upper portion, which faces the back, has no self-inflating function, while the lower portion, which is located in the lordosis and iliac crest region of the human body, has a valve-controllable, self-inflating function. By this is meant that at rest, the inflatable cushion is fully filled with air. A user who wants to use the work chair in an ergonomic way now proceeds as follows:

He sits down on the work chair and leans against the backrest with his back. Thus, it creates a pressure on the inflatable cushion in the lordosis and iliac crest area and by opening the valve, so much air is now vented that the inflatable air cushion rests in a particularly favorable manner on the back in the lumbar and iliac crest area.

This creates effective support in this area, which is maintained as long as it does not move.

This is a major disadvantage of a self-inflating cushion with a supporting effect in the lordosis and iliac crest area, because no dynamic sitting is possible. Namely, the cushion maintains its volume of air unchanged as long as the valve is not operated, regardless of whether the user moves on the seat or the backrest or not.

Thus, the inflatable back element always has the same hardness, regardless of whether the user pushes his back now obliquely into the seat or moves his back down more on the seat and occupies a different sitting position. Thus, with such an arrangement no dynamic sitting with a simultaneous support of the back in the lumbar and iliac crest region depending on the sitting position of the user is possible.

Another disadvantage is that an adjustable support is given only in the lower part of the backrest, but not in the upper part.

A complete adaptation to the contour of the back of a user, d. H. So even at the shoulder area is not provided in this document, because only the lower portion of this inflatable cushion is changeable.

With the subject of DE 201 20 023 U1 a cushion arrangement is described consisting of a plurality of inflatable pads, wherein the pads are arranged both in the back region and in the lumbar region and additionally in the seating area more pads are arranged. The said pads can be inflated separately by an air pump and their degree of filling can be adjusted by a respective valve associated with the pad.

Disadvantage of such an air cushioning system is that no dynamic sitting is possible, d. H. the degree of filling of the individual pads is not dependent on a dynamic sitting of the user on the various support and seating surfaces. It is always set only a certain degree of filling and only based on a specific seating position, with a different degree of filling must be set when changing the seating position.

It also follows from this document that the air chambers arranged in the back region and in the lordosis region are connected to one another in an air-tight manner and are connected via a hose arrangement which is provided with a controllable valve.

Disadvantage of this arrangement is that the arranged in the backrest upholstery are not directly connected to each other airtight, but over relative thin, long tubes that cause a large pressure drop. These hoses are interconnected in the seating area with a valve and air manifold assembly.

Therefore, it requires a relatively large force on the arranged in the shoulder area, upper cushion to displace the air there by a significant amount and possibly hineinzufördern in the middle area (lordosis) arranged cushion. Due to the large hose lengths, a significant pressure drop is to be feared, so that the cushion arranged in the lordosis area in the backrest is inflated only with a great time delay.

The basic principle of this air cushion system is therefore that with a pump separate air cushions are inflated and the degree of filling of the individual air cushion is maintained. Due to the arrangement of the connecting hoses, the system is sluggish, because only a sluggish system is possible through the individual connecting hoses, whose total length adds up to a length of 2 meters. In addition, due to the thin connecting hoses, flow noise is to be feared. A dynamic sitting, d. H. an air distribution in the backrest depending on the seat and upper body position of the user is not provided in this system.

With the subject of CH 412 594 A a vehicle seat is described with arranged in the backrest air cushions, which are inflatable separately.

Again, a dynamic sitting is not possible because the individual arranged in the backrest upholstery do not have an air-tight connection with each other, but are separately inflatable.

The invention is therefore based on the DE 198 27 683 C1 the task of forming a work chair of the aforementioned type so that a dynamic sitting position of the user in the work chair (based on the backrest and the seat) directly to a change in the Inflation condition depending on the sitting position of the user on the work chair leads.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

An essential feature of the invention is that in the backrest region of the work chair at least one filled with foam air cushion is arranged, which has a lockable volume of air and that the air cushion has at least one vertical slot whose slot end extends into the lumbar region and the slot opening is arranged in the iliac crest region.

For ease of description, only a single inflatable foam-filled air bag will be described because the air cushions in the seat back and seat are identically constructed and exert the same effects. It is therefore sufficient to describe the effect and the structure of a single air cushion in order to describe the structure and the effect of the other, complementary air cushion.

For reasons of simplicity, therefore, only the air cushion in the backrest and its effects are described because the air cushion in the seat has exactly the same effects and the same structure.

According to the invention, the air cushion in the backrest is filled with foam. This feature has the advantage that can be largely dispensed with on the surrounding foam in which this air cushion is embedded, d. H. it is a relatively thin foam layer of a backrest foam, which is directed against the user's back, used because the inflatable air cushion according to the invention itself carries a foam layer.

Namely, filling an inflatable air cushion with a foam results in a much more homogeneous pressure distribution in the cushion and also no peak pressures, and no undesirable bloat in certain areas, d. h., there is a homogeneous expansion of the air cushion when changing the pressure.

It is also possible to manage with lower pressures in the interior of the air cushion, if this is filled from the outset with a foam.

The invention also relates to two different embodiments for the inflatability of the air bag. In a first embodiment, it is provided that the air cushion itself is inflatable. Such a self-inflatable cushion is for example in the DE 198 27 683 C1 described. This means that in the interior of the air cushion, an open-cell foam is arranged, which has such a compressive capacity that the foam always absorbs a certain amount of air in the expanded state of rest. To vent air upon pressure on this self-inflatable air bag, a valve is provided which is opened to release a certain amount of air from the air bag and the open foam pores in the air bag.

Thus, an adaptation to the back contour of the user is possible if this leans against the air cushion.

In another embodiment of the invention, it is provided that the air cushion is not filled with a self-inflatable foam, but works only with a (closed-cell or open-cellular) foam and with an attached air pump. By operating the pump thus the degree of filling of air in the air cushion can be more or less influenced.

Preferably, a vertical (that is, a vertically extending with its longitudinal extension) slot in the lower region of the air cushion is arranged and the air cushion extends in the backrest approximately from the shoulder region down to the iliac crest region. The plane of the vertical slot is approximately parallel to the plane of the back shell.

Further, the vertical slot extends approximately from the middle of the lumbar region (where the slit end extends horizontally about the entire width of the back) down to the iliac crest region where the expandable slit opening is located.

Thus, the air cushion in the lower area, d. H. formed spreadable in the lumbar region and in the iliac crest region. D. h., It consists of at least two opposing wing-like expansion parts, which are separated by the vertical slot from each other and support each other in the inflation of the air cushion from each other and thus spread.

Now pushes a user with the weight of his back against the upper part of the inflatable air cushion, then a displacement force is exerted on the air cushion and the pressure in the air cushion increases by. As a result, the volume of air from the upper region of the air cushion, which faces the back of the user, displaced downwards and the two wing-like expansion parts (spreading) of the air cushion, which are arranged in the lordosis and iliac crest area, spread by the air volume flowing there , which was displaced from the upper area.

This results in a Abspreizwirkung of the air cushion in the direction of the lordosis and iliac crest region (that is, ie in the lower region of the back shell) and thus a favorable support force is achieved on the lumbar and iliac crest region of the user.

It is therefore important that when the user leans against the upper region of the self-inflatable air cushion with his back that this air cushion initially optimally adapts to the user's back contour and the displaced from the upper area, excess air volume is down in the Lordosis and the iliac crest area. The local expansion part spreads now due to the vertical slot specified there and it thus takes place a counterforce on the lordosis and iliac crest area, d. h., a high pressure force is exerted on this area of the user's back. This is ergonomically sensible and desired.

It is important that the Abspreizweg - that is, the blowing effect of the expansion part - is much stronger than comparatively the Blähweg an unslotted pad, because preferably the two wing-like expansion parts abut against each other, supported against each other and so the Abspreizweg - in comparison to an unslit air cushion - enlarge and strengthen.

The air cushion allows a backrest shape adapted to the individual back contour. This mode of operation allows, in principle, a quasi-automatic adaptation to the altitude and protrusion depth of the individual spine contour, without the need for mechanical adjustment mechanisms for backrest contouring.

In particular, with increasing Lehnenrückneigung an intensification of the supporting effect in the lordosis is to be expected, which in turn means a positive, functional load interaction for the intervertebral discs with the support of the diffusion processes.

Also for the backrest surface is that their hardness can be adjusted individually using the air cushion - an aspect that is also at least to adapt to the subjective sense of comfort after softer or harder upholstery of interest.

When sitting in the area of the front half of the seat, the effect of the air cushion is comparable to that of a seat wedge - thus requiring an intensification of the Sitzflächenvorneigung coupled with increased support in the rear pelvic area. Both of these effects are to be considered positive insofar as this counteracts an unwanted total laryngeal laryngeal affection. The air cushion enables increased movement possibilities on the seat surface in the lateral direction, which are to be regarded positively under the aspect of "seat dynamics".

The hardness of the seat cushion can be adjusted individually. This is important for adapting to individual physical conditions (avoidance of "sitting through") as well as for adapting to the subjective sense of comfort - ie the desire for softer or harder upholstery. This makes it clear that there is a dynamic support in the back and in the seating area, which depends on the sitting posture of the user and changes with the sitting posture of the user.

The support force in the lumbar and iliac crest area is thus dependent on the force with which the user presses with his upper back on the self-inflatable air cushion.

The same applies to the seating area. There, the support force and the spreading force of the seat cushion arranged there are dependent on the extent to which the user shifts his weight on the seat forward or backward.

When the pressure from the thigh becomes large, the seat cushion should inflate and spread in the region of the ischial tuberosity in order to support the ischial tuberosity ergonomically.

Thus, the particular advantage of the invention is that at least one continuous air cushion filling the backrest region of the backrest is arranged so that the air can flow from the upper part of the air cushion into the lower part of the air cushion in order to spread off the lower part.

The arrangement of at least one vertical slot thus provides the advantage that a large spreading effect is achieved with a relatively small displaced air volume. This is because the two wing-like expansion parts support each other and thus the spreading effect - compared to an unslit air cushion - increased (multiplied).

This was not known before. The same applies to the seat cushion area, where a small spreading of air in the region of the seat cushion can achieve a large spreading effect in the area of the ischial tuberosities.

Of course, the present invention is not limited to the arrangement of a single vertical slot. It can also be several parallel juxtaposed vertical slots exist or it can There may also be lateral slots which divide the seat in the vertical direction.

Furthermore, in a third embodiment, it is possible to arrange a central slot which is delimited by outer connecting webs.

It is important in the present invention that, based on the backrest area, the back contour of the user is supported irrespective of the height of the user.

In the prior art, this was not possible. In the DE 201 20 023 U1 There were two separate airbags, with the upper airbag being associated with the top of the back. The same applies to the DE 198 27 683 C1 , in which only in the lower part of the back, a corresponding pad is arranged, while in the upper part of the back no adaptation to the back contour of the user takes place, because there is no luftverdrängendes cushion.

The invention thus relates to the fact that the entire back contour of the user effectively by - a single, continuous air cushion is supported, so when pressure in the upper shoulder area on this air cushion, the air displaced there to achieve a spreading effect in the lordosis and pelvic area is used ,

Because the back cushion extends over the entire length of the back, so is the support effect regardless of the size of the user. Thus, not only certain areas are supported, as in the prior art, but a large area of the entire back shell of the work chair.

With regard to the spreading effect in the seating area, it is emphasized that dynamic seating is likewise possible there because, in accordance with the load of the air cushion arranged there, a dynamic seat wedge in the seat is provided Ischial tuberosity area is generated. This results in a Sitzvorneigung (negative seat tilt), when a thigh pressure of the user displaces the corresponding air from the front of the air cushion in the rear area and there brings the expansion for spreading.

Due to the fact that both the air cushion in the backrest area as well as the air cushion in the seating area is filled with air, there is an avoidance of slipping through there arranged in the surrounding area foam. The air can not escape from the seat cushion due to the closed system, and a foam located in the surrounding area of the airbag could also be sloshed without adversely affecting the seating comfort. It can therefore be used thinner foam thicknesses and overall, thus lower production costs can be achieved.

In addition, an attractive design, because with good cushioning effect, a thin foam layer can be used.

Figur 1:

Schematisiert eine Darstellung eines Arbeitsstuhles mit Luftkissen im Lehnen- und im Sitzbereich im nicht gespreizten Zustand.

Figur 2:

Die gleiche Darstellung wie Figur 1, für den Fall, dass sich der Benutzer an die Lehne anlehnt und das lehnenseitige Luftkissen sich aufspreizt.

Figur 3:

Eine Draufsicht auf die Anordnung nach Figur 1 mit Schnitt durch die Sitzfläche.

Figur 4:

Die Schnittansicht (Stirnansicht) des Luftkissens im nichtgespreizten Zustand.

Figur 5:

Eine perspektivische Ansicht des Luftkissens nach Figur 4 im gespreizten Zustand.

Figur 6:

Schematisiert die Bewegungsrichtungen des Luftkissens nach den Figuren 4 und 5 beim Aufspreizen.

Figur 7:

Eine gegenüber den vorherigen Figuren abgewandelte Ausführungsform eines Luftkissens mit zwei zueinander parallelen Schlitzen.

Figur 8:

Eine weitere Abwandlung des Luftkissens nach Figur 7 mit zwei seitlichen Luftschlitzen.

Figur 9:

Eine weitere Abwandlung eines Luftkissens mit einem zentralen Schlitz.

Show it:

FIG. 1:

Schematisiert a representation of a work chair with air cushion in the backrest and in the sitting area in the non-spread state.

FIG. 2:

The same representation as FIG. 1 in the event that the user leans against the backrest and the reclining air cushion spreads.

FIG. 3:

A plan view of the arrangement according to FIG. 1 with cut through the seat.

FIG. 4:

The sectional view (front view) of the air cushion in the non-expanded state.

FIG. 5:

A perspective view of the air cushion after FIG. 4 in the spread state.

FIG. 6:

Schematisiert the directions of movement of the air cushion after the FIGS. 4 and 5 when spreading.

FIG. 7:

An opposite to the previous figures modified embodiment of an air cushion with two parallel slots.

FIG. 8:

Another variation of the air cushion after FIG. 7 with two side louvers.

FIG. 9:

Another variation of an air cushion with a central slot.

In FIG. 1 is a functional position shown in which a user does not lean on the work chair and the backrest shell 1 there. The work chair consists essentially of the backrest shell 1 and the seat shell 7. On the backrest shell 1, the self-inflatable air cushion 3 according to the invention is on the inside arranged in front of - in the direction of the back of the user a backrest foam 2 is arranged.

The same applies to the seat cushion, wherein the self-inflatable air cushion 9 according to the invention is arranged directly on the seat shell 7, which is covered at the top by a seat foam 8.

Gem. FIG. 3 The backrest foam 2 and the seat foam 8 also extend beyond the lateral boundaries of the respective air cushion 3, 9 arranged there.

It is now important that at least one vertical slot in the air cushion 4 is arranged in the lower region of the air cushion 3 arranged on the back side.

The same applies to the seating area, wherein in the local air cushion 9 a rearwardly directed slot 10 is arranged, the expansion part extends in the rear region of the seat cushion.

The effect of the reclining-side airbag 3 is in FIG. 2 explained.

Leaning the user in the direction of arrow 17 with the force F1 against the back shell 1, he displaces the air from the shoulder region 14 from the air cushion 3 down so that this air in the lower region, namely the lumbar region 15 and the iliac crest region 16 of the Air cushion 3 flows.

This spreads the two wing-like expansion parts 11, 12 (see FIG. 5 ) against each other, so that thus results in a spreading effect in the direction of arrow 18 on the lumbar region and the iliac crest region 15, 16 with a force F2 for the user.

With the valve 5, the basic filling of the air bag 3 can be adjusted, which is preferably self-inflatable.

The same applies to the valve 6, which adjusts the basic filling of the air bag 9 in the seating area.

The FIG. 3 shows that the lean-side air cushion 3 extends in its upper limit in the shoulder region 14 of the back and covers the lordosis region 15 and the iliac crest region 16.

Accordingly, if the force F1 is generated in the arrow direction 17 in the shoulder region 14, the air flows down into the region of the slot 4 and brings the lower region (ie the expansion parts 11, 12) for mutual lifting, so that thus a force F2 in the direction of arrow 18th is created on the lower back of the user.

Accordingly, the air cushion 3, 9 according to the invention has in each case one compression region 13 and two expansion parts 11, 12 separated from one another by at least one single slot 4, 10.

In FIG. 4 Such a cushion 3, 9 is shown in the unexpanded state. It can be seen that it is surrounded by a sheath 20 which is closed by Verbindungsfalze 21 and is airtight.

In the region of the slot thus results in a minimum distance 19 gem. FIG. 4 ,

If, however, gem. FIG. 5 generates a force F1 on the air cushion 3, 9 in the compression region 13, then there is a spreading of the two expansion parts 11, 12 generated by mutual support in the region of the vertical slot 4, 10, as in FIG. 5 is shown.

The mutual distance 19 of the two expansion parts 11, 12 thus increases to the distance 19 '.

When referring to a vertical slot 4, 10, this refers to the reclining side slot 4. However, the horizontal slot 10 disposed in the seat cushion is meant to be analogous.

The FIG. 6 shows again the operating principle of the present invention, where it can be seen that the force F1 in the compression region 13, 14 on the cushion 3, 9th In this case, it can be seen that the inflation of the reclining expansion part 12 does not lead to a spreading, because the force F2 is derived in the back shell 1 and is forwarded as a counterforce to the increased spreading to the back-side expansion part 11. Therefore, the Abspreizwirkung the back-side expansion part 11 is substantially larger, because the spread is supported by the reclining side expansion member 12.

The FIG. 7 shows a modified embodiment in which two mutually parallel vertical slots 4a, 4b are present. This results in a spread around the distance 19 ', so that this distance is double.

Otherwise, the same explanations apply to the same parts.

The FIG. 8 shows a further modified embodiment, in which lateral slots are present, which are interconnected by a central connecting web 22.

These lateral slots lead to an arcuate spreading of the two expansion parts 11, 12, which may be advantageous in terms of adaptation to a rounded back contour.

The FIG. 9 in contrast shows a central central slot 4, 10, so that only results in a central spreading. The local expansion part will therefore bulge convexly, while the part after FIG. 8 concave bulges.

All embodiments are claimed essential to the invention in isolation or in combination with each other.

The slot length 23 of the slot 4, 10 is preferably selected so that the slot end 25 extends in the lean-side air cushion 3 to approximately in the lumbar region 15 or in the near thigh area at the seat-side air bag 9 ( Fig. 3 ).

The spreadable at a distance 19, 19 'slot opening 24 thus describes the Aufspreizwirkung the air cushion 3, 9 (FIG. Figure 5 ).

In the drawings it is shown that the air cushions 3, 9 have a rectangular shape substantially in cross section. Accordingly, the mutually parallel and abutting expansion parts 11, 12 have such a rectangular shape. However, the invention is not limited thereto. In a modified embodiment, it can be provided that the air cushion has in section an oval or another shape deviating from the rectangular profile. Accordingly, the expansion parts have an oval or another, adapted profile.

Furthermore, it is shown in the drawings that the air cushions 3, 9 have a rectangular shape in plan view. However, this is not to be understood as limiting the invention. It can be provided that the air cushion in plan view have a tapered shape. Likewise, other shapes are possible.

Important in the present invention is that a delay-free dynamic sitting with a corresponding seating position with a dynamically resulting support force on the lumbar and iliac crest region or the ischial tuberosity area results. This up or Abspreizkraft is independent of the height of the user and does not need to be adjusted to the height. Due to the fact that the air is enclosed in the two air cushions 3, 9, there are no disturbing flow noises, as were the case in the prior art, because in the prior art air-connecting hoses were arranged between air cushions.

Because of the delay-free adaptation to the back contour and the pelvic contour of the user, there are no pressure peaks when changing the sitting position. Next there is the advantage that a height-adjustable backrest can be omitted, because the adaptation to different heights back contours automatically. A height adjustment mechanism of the backrest can thus be omitted.

drawing Legend

1.

backrest shell

Second

sit foam

Third

Air cushion (backrest)

4th

Slit air cushion backrest

5th

Valve air cushion backrest

6th

Valve Seat Cushion Backrest

7th

seat

8th.

seat foam

9th

Air cushion (seat)

10th

Slit air cushion seat

11th

expansion part

12th

expansion part

13th

compressing region

14th

shoulders

15th

lordosis

16th

Iliac crest area

17th

arrow

18th

arrow

19th

distance

19 '.

Distance spread

20th

Wrapping (airtight)

21st

Verbindungsfalz

22nd

connecting web

23rd

slot length

24th

slot opening

25th

Slashing

Claims (21)

1. Work chair with air-padded support faces, in which a preferably self-inflating air pad, which has a closable air volume and which is directed against the back of the user, is arranged at least in the backrest (1, 2), at least one air cushion (3) filled with foam being arranged at least in the backrest region (1, 2) of the work chair, characterised in that the air cushion (3) has at least one vertical slot (4), the slot end (25) of which extends into the lumbar region (15) and the slot opening (24) of which is arranged in the iliac crest region.
2. Work chair according to claim 1, characterised in that the work chair has at least two different air cushions (3, 9), working separately from one another and filled with foam, one air cushion (3) being arranged at least in the backrest and the other air cushion (3) being arranged at least in the seat face.
3. Work chair according to either of claims 1 or 2, characterised in that an open-cell foam, which has a compression capacity such that the foam in the expanded rest state absorbs a specific quantity of air and emits it on compression, is arranged in the interior of the air cushion.
4. Work chair according to any one of claims 1 to 3, characterised in that, in relation to the backrest (1, 2), a vertical slot (4), in other words a slot extending with its longitudinal extent in the vertical direction, is arranged in the lower region of the air cushion (3).
5. Work chair according to claim 4, characterised in that the air cushion (3) in the backrest extends approximately from the shoulder region downward into the iliac crest region.
6. Work chair according to either of claims 4 or 5, characterised in that the vertical slot (4) extends approximately from the centre of the lumbar region (15) downwardly into the iliac crest region (16), where the expandable slot opening (24) is located.
7. Work chair according to any one of claims 4 to 6, characterised in that the slot end (25) extends horizontally approximately over the entire width of the backrest.
8. Work chair according to claim 7, characterised in that the air cushion (3) is spreadable in the lower region, i.e. in the lumbar region and in the iliac crest region.
9. Work chair according to claim 8, characterised in that the air cushion (3, 9) consists of at least two mutually opposing, wing-like expansion parts (11, 12), which are separated from one another by the slot (4, 10) and are mutually supported by one another and therefore spread apart when the air cushion (3, 9) is inflated.
10. Work chair according to claim 9, characterised in that the air cushion (3) optimally adapts to the back contour of the user and the excess air volume displaced from the upper region is guided downwardly into the lumbar and the iliac crest region, and in that the expansion part (11, 12) spreads apart because of the vertical slot (4).
11. Work chair according to claim 10, characterised in that a plurality of vertical slots (4) arranged in parallel next to one another are present.
12. Work chair according to claim 11, characterised in that lateral slots are also present and divide the seat face in the vertical direction.
13. Work chair according to claim 12, characterised in that a central slot is present, which is limited by outer edge connection webs.
14. Work chair according to claim 13, characterised in that the back cushion extends over the entire length of the back and in that the support effect is therefore independent of the body size of the user.
15. Work chair according to claim 14, characterised in that in relation to the air cushion (9), a slot (10) directed rearward, the spreading part of which extends into the rear region of the seat cushion, is arranged in the seat region.
16. Work chair according to claim 15, characterised in that the air cushion is surrounded by a cover (20), which is closed by connection folds (21) and is air-tight.
17. Work chair according to claim 16, characterised in that two mutually parallel slots (4a, 4b) are present in the backrest-side and/or seat-side air cushion.
18. Work chair according to claim 17, characterised in that lateral slots are present in the backrest-side and/or seat-side air cushion and are connected to one another by a central connection web (22).
19. Work chair according to claim 18, characterised in that at least one central mid slot (4, 10) is arranged in the backrest-side and/or seat-side air cushion.
20. Work chair according to claim 19, characterised in that in the backrest-side air cushion (3), the slot length (23) of the slot (4, 10) is selected such that the slot end (25) extends approximately into the lumbar region (15).
21. Work chair according to claim 20, characterised in that in the seat face-side air cushion (9) the slot length (23) of the slot (4, 10) is selected such that the slot end (25) extends into the close thigh region.

Images