WO1995015101A1

WO1995015101A1 - Upholstered seat for an office chair

Info

Publication number: WO1995015101A1
Application number: PCT/EP1994/004008
Authority: WO
Inventors: Burkhard Vogtherr
Original assignee: Fritz Hansen A/S
Priority date: 1993-12-02
Filing date: 1994-12-02
Publication date: 1995-06-08
Also published as: DE4341070A1

Abstract

A tiltable seat (12) of an office chair has a cushion (30) in which is embedded a contoured seating piece (28) which, viewed from below, has a convex midseat. Parts of the cushion (30) situated between the underside of the seating piece (28) and the upper side of the seat base (18) form block springs (38, 42) which prestress the seating piece (28) at rest and enable the load-carrying seat to tilt with restoring force dependent on the weight of the user.

Description

Upholstered seat for an office chair

The invention relates to an upholstered seat for an office chair according to the preamble of claim 1.

For some applications it is advantageous if such a seat can automatically adapt to the user's sitting posture. Adjusting the inclination of the seat of an office chair is known per se for expensive functional chairs, but this requires complex mechanical bearings and guides.

The present invention is therefore intended to develop a seat in accordance with the preamble of claim 1 in such a way that the seat inclination can be adapted to the current needs of the user with little construction effort.

This object is achieved according to the invention by a ge padded seat with the features specified in claim 1.

Advantageous developments of the invention are specified in the subclaims.

Are known seats with relatively smooth coverings, e.g. If a leather cover is used in office chairs, in which the backrest can be pushed back against spring force, and if the user leans back heavily on this chair, there is a risk of it sliding forward on the seat.

In the case of a seat according to claim 2, it is not only the seat part itself that constitutes an obstacle to sliding forward represents, the convexly curved section of the seat part also represents a weir, in front of which the elastically deformable soft material of the cushion body jams when the user slides forward, thereby providing additional, very effective protection against such slipping forward .

Another advantage of a seat according to claim 2 is that the molded cushion body and resilient material volumes, which are arranged between the underside of the seat part and the top of the base part, can be produced as a single molded part. This is advantageous not only in terms of manufacturing costs but also in terms of simple and quick assembly of the seat.

The development of the invention according to claim 3 is advantageous in terms of a simple setting of different hardness of the seat over its different areas. In this way it is possible to achieve a relatively hard sitting without unpleasant pressure.

With the development of the invention according to claim 5, the deformation of the seat part can be adjusted particularly well depending on the load on the seat.

According to claim 6, elastic springs for prestressing the seat part into a horizontal rest position can be realized in a very simple manner. The corresponding rubber springs are also captively connected to the molded cushion body by injection molding or foaming, which facilitates handling and assembly. With regard to keeping the number of manufacturing steps small and the use of the same materials throughout, it is particularly advantageous according to claim 7 if the same material is used for the elastic filler material as for the molded cushion body.

If necessary, the spring force can be locally reduced by providing recesses or cavities in the corresponding foam areas.

The development of the invention according to claim 9 is advantageous in terms of simple and inexpensive manufacture of the seat.

According to claim 10, one obtains a low-cost, easy-to-assemble load-bearing tilting bearing of the seat part on the seat base.

The further development of the invention according to claim 11 gives a substantially smooth underside of the seat, so that the user's fingers cannot get caught between the seat parts that are moving against each other. In addition, positioning of the seat surface part over the seat base part is also obtained in this way.

According to claim 12, the spring behavior of the seat surface can be varied.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawing. In this show:

Figure 1: a lateral, partially in the longitudinal center flat sectioned view of an office chair;

FIG. 2 shows a section through a molded cushion body of the office chair according to FIG. 1 on an enlarged scale;

Figure 3: a side view of a modified seat part for the seat of the office chair shown in Figure 1;

FIG. 4: a vertical section through a again modified molded cushion body for an office chair similar to that shown in FIG. 1; and

Figures 5 and 6: similar sectional views as Figure

1, in which modified office chairs are reproduced.

The office chair shown in FIG. 1 has a foot section, designated overall by 10, a seat designated overall by 12, a backrest designated overall by 14, and a seat height adjustment device designated overall by 16.

The seat 12 has a seat base part 18 made of sheet metal, to which a backrest base part 22 is pivotably attached via a link 20.

On the seat base part 18, a hard seat part, designated overall by 28, is attached by means of a shaft 24 and lateral support legs 26, which is embedded in a foamed upholstery body 30 and is made, for example, of plywood or plastic sheet material. The seat surface part 28 is bent as shown and has a front plate section 32 which is convexly curved from above and spaced from the seat base part when the seat is not under load, a central plate section 34 which is concave from above and convexly curved from below and a rear, again obliquely rising and when the seat is unloaded from the seat base 18 spaced plate section 36.

As can be seen from the drawing, the material of the molded cushion body 30 completely surrounds the seat part 28 so that between the underside of the seat part 28 and the upper side of the seat base part 18 three material volumes 38, 40 consisting of the resilient material of the molded cushion body 30 42 receives, which lie under the plate sections 32, 34, 36. Of these, the material volumes 38 and 42 form roughly wedge-shaped rubber block springs.

Possibly. For example, recesses or cavities can be provided in the material volumes 38, 42, as shown by way of example at 44, in order to reduce the spring constant of the block spring under consideration for a given plastic foam material.

When the seat is under load, these rubber block springs are under a pretension that is proportional to the weight of the user. The restoring force on the seat, which counteracts a counter-clockwise and clockwise rotation, is also dependent on the weight of the user. By changing the sitting posture or by shifting weight on the seat 12, the seat 12 is tilted out of the horizontal by compressing the material volume 38 or the material volume 42, this being the case for light people only low forces, larger forces are necessary for heavier people.

In FIG. 1, the maximum tilt that can be obtained when the front seat section is loaded is shown in dashed lines at 12v (approximately 10 degrees), which is predetermined by striking the seat part 28 on the seat base.

At 12h, a maximum tilted backward position (approximately 3 degrees) of the seat 12 that is reached in practice when the rear seat section is loaded is indicated by dashed lines.

In the drawing, 46 denotes a recess in the underside of the molded cushion body 30, in which the seat base 18 is received.

If a user leans back on the office chair described above, the material of the molded cushion body 30 in FIG. 1 is also pushed to the left and jams in front of the convex plate section 32. In this way, the user is prevented from sliding forward. In the event of very strong reclining, the plate section 36 also springs in against the seat base 18, as indicated by further dashed lines.

In the modified seat surface part 28 according to FIG. 3, leaf springs 48 are formed in the rear plate section 36, which are formed laterally and extend downward to the seat surface base part 18 and support there, which modify the spring characteristic for the additional deflection of the plate section 36 indicated by the broken line in FIG. In the seat shown in FIG. 4, the molded cushion body 30 is made from relatively hard foam material. The contour of its underside essentially corresponds to the contour of the seat surface part 28 according to FIG. 1. The gaps between the underside of the hard molded cushion body 30 and the top of the seat base part 18 are filled by a spring body 50, which is made of a soft foam material and which is the material volume 38, 40, 42 forms. In the simplified exemplary embodiment according to FIG. 4, the deepest point of the convex underside of the hard molded molded body 30 also forms a tilting bearing for the seat 12, so that the support legs 26 and the shaft 24 can be omitted.

In the office chair shown in FIG. 5, the seat part 28 is a one-piece molded part. In the front area, it is provided with an upward-running end rib 52, which lies in or just behind the surface of the cushion molded body, and has four closely adjacent downward-running bearing ribs 54 approximately in the middle between the axis of the adjusting device 16 and the front edge of the seat. The front and back of these have a slightly shortened height. The bearing ribs 54 lie above an upper wall 56 of the seat base part 18 produced as an aluminum casting. The bearing ribs 54 together with the upper wall 56 thus form a tilting bearing for the seat surface part 28.

The seat part 28 also has a circumferential wall 58, which is adjoined by a lower end wall 60 with a short wall section 62 which is curved back upwards. The wall section 62 lies with little play in front of a circumferential wall 64 which runs upwards at the edge of the seat base 18. In this way, the seat flat part 28 positioned over the seat base part and the underside of the seat base part together with the underside of the seat surface part 28 forms a substantially smooth, continuous surface. Similarly, the seat base 18 in the vicinity of the handlebar 20 has a peripheral wall 66 and the handlebar 20 has an opposite peripheral wall 68. Furthermore, a bottom wall 70 of the seat base 18 and a bottom wall 72 of the handlebar 20 are aligned, so that the underside of the seat is smooth and the user's fingers cannot get anywhere between moving parts of the office chair.

As can also be seen from FIG. 5, the handlebar 20 has stop ribs 74 which stand upwards in the rear section and cooperate with aligned stop ribs 76 which are cast onto the seat base part 18. In this way, the steep end position of the backrest 14, which is set by spring preload, is predetermined.

In addition, armrests 78 are shown in FIG. 5, which are attached to the handlebars 20 in a height-adjustable manner via an elongated hole connection 80.

In the exemplary embodiment according to FIG. 5, foam is only on the upper side of the seat part 28. If desired, the seat part can be elastically pretensioned into the horizontal basic position by one or more rubber block springs 82, which are located between the upper side of the floor - Wall 70 and the underside of the seat part 28 are provided in the front third.

The exemplary embodiment according to FIG. 6 shows a modified seat surface part 28, which is also provided with hanging bearing ribs 54. This seat This part is now also elastically deformable, whereby it is given again by solid lines in the unloaded state and hatched in the state deformed by the weight of a user when the backrest 14 has been pushed back under the weight of the user (solid lines; unloaded chair shown in broken lines).

It is understood that the molded cushion bodies of the seats described above are normally provided with a cover made of fabric or leather in practice. This can have a simple geometry due to the design of the upholstered molded body, which is interesting both in terms of manufacture and for aesthetic reasons.

Claims

claims

1. Padded seat for an office chair, with one

Seat base (18) and a molded cushion body (28, 30; 30) carried by it, characterized in that the underside of the molded cushion body (28, 30; 30) is convex when viewed from below at the center of the seat and a front (32) and / or the rear (36) section of the upholstered molded body (28, 30; 30) is spaced from the seat base (18) and that the upholstered molded body (28, 30; 30) is supported by the seat base (18) so that it can be tilted or pivoted (24, 26) is.

2. Upholstered seat according to claim 1, characterized gekenn¬ characterized in that the underside of the molded cushion body

(28, 30) has a contoured hard seat part (28).

3. Upholstered seat according to claim 2, characterized gekenn¬ characterized in that the seat part (28) is made of resilient material.

4. Upholstered seat according to claim 3, characterized gekenn¬ characterized in that the seat part (28) made of plate-shaped material, e.g. Laminated wood is made.

5. Upholstered seat according to claim 4, characterized in that the seat part (28) in a rear portion (36) has leaf springs (48) which run down to the seat base (18) and are supported thereon.

6. Upholstered seat according to one of claims 2 to 5, characterized in that the gaps between the underside of the seat part (28) and the top of the seat part (18) are at least partially filled with elastic spring material (38, 42; 82).

7. Upholstered seat according to claim 6, characterized gekenn¬ characterized in that the elastic spring material (38, 42) is formed by molded portions of the cushion body (30).

8. Upholstered seat according to claim 7, characterized gekenn¬ characterized in that the elastic spring material (38, 42)

Contains recesses (44) or cavities.

9. Upholstered seat according to claim 1, characterized gekenn¬ characterized in that the cushion molded body (30) made of hard

There is foam material and the gaps between the underside of the molded cushion body (30) and the upper side of the seat base (18) are at least partially filled with elastic spring material (38, 42).

10. Upholstered seat according to one of claims 2 to 9, characterized in that the underside of the seat part (28) carries a rib arrangement (54) which rests tiltably on an upper wall (56) of the seat base (18).

11. Upholstered seat according to claim 10, characterized in that the seat part (28) has a downward peripheral wall (28 to 62) which overlaps a peripheral wall (64) of the seat base (18) with little play.

12. Upholstered seat according to claim 10 or 11, characterized in that the front section (32) and / or the rear section (36) of the seat part (28) is elastically bendable.