EP1659902A1 - Chair or stool comprising mobile, elastic legs, permitting a dynamic sitting position - Google Patents

Abstract

The invention relates to a chair comprising a seat part (2), at least one leg part (3), at least one foot part (5) that consists of a predetermined plurality of foot elements (4) and at least one spring assembly (6). According to the invention, at least one designated foot element (4) and/or a sub-section (4') of said element is configured to be mobile and is subjected to a restoring moment under the action of a load.

Description

Chair or stool with flexible, elastic legs to allow dynamic sitting

The invention relates to chairs with a foot part with at least three movable, resilient foot elements which are connected to a leg part of the chair.

The priority of German patent application DE 10338549.1, which was filed on August 19, 2003 and is entitled "Pendulum Chair", is claimed.

Office chairs are often provided with a star-shaped foot part, at the ends of which a roller is provided. The mobility of an office chair is essentially limited to a height adjustment using a gas spring and the suspension of the backrest or seat. In addition, there are complex, mechanical systems that are expensive to manufacture and sometimes complex and only allow so-called dynamic sitting to a limited extent.

A pendulum stool that is suitable for dynamic sitting can be found in European patent application EP 0 808 116. With this pendulum stool, the pendulum movement is made possible by a rubber element arranged between the foot part and the leg part. This well-known pendulum stool works well and fulfills the task of actively dynamic sitting.

From WO 01/91615 AI a chair is known, which with soft springs

Chair feet and a weight-centered seat mechanism. The document discloses a five-star base, which is equipped at its free ends with rollers which are resiliently mounted on a rubber ring. As a further suspension with soft feet, a circular disk made of spring steel is described instead of a five-pointed star, which enables a lateral pivoting or wobbling movement. The present invention has for its object to propose a stool or a chair that enables dynamic sitting and is preferably easy to move.

The present invention has for its object to propose a stool or a chair in which the inherent favorable properties of the known pendulum stool are retained in a cost-effective manner, but which is cheaper and easier to manufacture.

Finally, the present invention has for its object to design with simple means rollable or slidable chairs so that significantly more movements of the user are possible without compromising safety and thus posture damage that arise when sitting rigidly are avoided ,

In addition, the aim is to provide a chair that makes it possible to sit safely and comfortably at a higher level. Above all, it should be avoided that such a chair can suddenly tip over in exposed positions.

The problems are solved by the teachings disclosed in independent claims 1 and 2.

According to the invention, a ^" chair is provided with a preferred embodiment, which has several support elements in the area of the foot elements, which are arranged on a spring-elastic foot part of the chair. When the chair is loaded, a lowering movement of the chair and at least one of the support elements results yourself in relation to a stand area.

In order to achieve this, foot elements of the chair can either be spring-loaded or they can be springy in terms of material and / or structure. A combination of a resilient bearing with inherently resilient foot elements is also possible.

Advantageously, a desired restoring force can be set over partial areas of the 360-degree rotation range of the foot part by a special embodiment, so that, for example, an unintentionally strong swinging backwards can be reduced by a larger restoring force.

[0014] A chair according to the invention makes it possible to move up and down when seated by using a spring-elastic foot part, which dynamically see relief of the spine. In addition, a chair according to the invention has a supporting effect when standing up and sitting down. This, for example, dampens blows to the spine when sitting down. Moving up and down is achieved without the need for a special vertically arranged spring element, for example in the form of a spiral spring, in the foot part of the chair, solely through the resilient mounting or the elasticity of the foot elements

Since new ergonomic findings place significantly higher demands on the variability and flexibility of chairs, the present invention offers solutions for dynamic sitting on chairs. In particular, the present invention is suitable for use in chairs which have support elements (rollers, gliders or the like).

It is an advantage of the invention that the corresponding chairs enable an active rocking / tilting movement that is healthy.

It is a further advantage of the invention that the corresponding chairs can be used flexibly, are movable and yet are safe.

The invention is, depending on the embodiment, suitable for simple retrofitting of existing office chairs.

An embodiment with star-shaped base elements in which the base elements and / or a partial element thereof can be pivoted up and down is advantageous, which makes it possible to specify the direction loaded by the pendulum movement by appropriate spring strengths.

A favorable embodiment is one in which at least one receiving area is formed in the lower area of at least one leg part, on which at least one of the foot elements is received. This receiving part can advantageously be designed in such a way that a foot element can be hung on it, with a counterpart holding this foot element in position.

An embodiment is favorable in which at least one spring arrangement is formed on a counterpart, which, however, can alternatively also be formed on the receptacle. In this case, the spring arrangement can advantageously consist of a piece of elastomer against which a region of the foot element or of the partial element rests.

[0022] As a further embodiment, a spring arrangement can be provided which comprises a tension or a compression spring which is attached to a leg part or to a nem receiving part is arranged and acts between at least one foot element and the leg part or the receiving part.

To adjust the spring force, an adjusting device is advantageously provided on the spring arrangement.

It may be favorable that an abutment is arranged on the two-sided end of the foot element, on which engages at least one spring element of the spring arrangement.

It can be advantageous that at least one of the foot elements at the end on both sides is designed as at least one slot that is essentially open at the bottom. In this way, it is advantageously achieved that the foot element can be simply hung in, and it can advantageously be provided that the foot element can be pivoted downwards and can be mounted at least in the position pivoted downwards by simple attachment.

It may be expedient to provide means which prevent the chair from moving in an uncontrolled translatory manner during a pendulum movement.

An embodiment is particularly advantageous in which the foot part comprises foot elements which are suspended mechanically with respect to the foot part in such a way that a resilient force is applied to them by a spring element. This restoring force counteracts an expansion swiveling movement which results when the chair is loaded and tries to pull the radially apart foot elements towards a central axis of the chair. The restoring force can preferably be made adjustable or specifiable.

In a preferred embodiment, the chair has a plurality of foot elements, at the foot end of which a role serving as a support element is attached via an inclined guide axis.

It can be favorable to provide means which prevent an uncontrolled translatory movement of the pendulum stool during the pendulum movement.

For this purpose, a means in the form of a stopper can be provided, which comes into contact with the floor at a predetermined inclination of the leg part and prevents a translational movement of the pendulum stool due to the friction with the floor.

[0029] This stopper can be connected to the leg part via an articulated connection. coupled, but it can also be rigidly attached to the leg part and come into contact with the ground at a predetermined inclination of the leg part.

However, in another embodiment, the stopper can also be arranged rigidly at the outer end of the foot and, in relation to a circumference on which all contact surfaces of the foot with the ground lie, are located radially outside of this common circumference.

Further details and advantages of the invention are described below with reference to exemplary embodiments and with reference to the drawing. Show it:

1A-1C are schematic sectional views of part of a conventional office chair;

2A-2B are schematic sectional views of a variant of an office chair;

Figure 3 is a schematic sectional view of the foot of a chair in an extreme position.

4A-4B are schematic side views of part of a first office chair according to the invention;

4C-4D are schematic top views of the first office chair under centric loading, according to the invention;

5A-5B are schematic side views of part of a second office chair, according to the invention;

6A-6B are schematic side views of part of a third office chair according to the invention;

7A-7B are schematic side views of part of a fourth office chair, according to the invention; 8A-8B are schematic side views of part of a fifth office chair, according to the invention; 9 is a perspective view of a sixth office chair according to the invention; 10A-10B are schematic side and sectional views of part of a seventh office chair according to the invention; 11A is a perspective view of part of an eighth office chair according to the invention;

11B-11E are schematic side, top and sectional views of the eighth office chair according to the invention; 12A-12B are schematic side and sectional views of a ninth office chair according to the invention;

13 shows a schematic side view of a tenth office chair according to the invention;

14 shows a schematic sectional view of an eleventh office chair according to the invention;

15 shows a schematic side view of part of a twelfth office chair according to the invention;

16 shows a perspective view of a foot part obliquely from above of a further embodiment according to the invention; 17 shows a schematic illustration of a next embodiment of an office chair, according to the invention;

18 shows a schematic illustration of a next embodiment of an office chair according to the invention;

19 shows a schematic illustration of a next embodiment of an office chair, according to the invention;

20 shows an illustration of an alternative detail of the embodiment according to FIG. 19;

21 shows a schematic illustration of a next embodiment of an office chair according to the invention;

22 shows a schematic illustration of a next embodiment of an office chair according to the invention;

23 shows a schematic illustration of an axial section through a pendulum stool according to the invention,

24 is a perspective view of a view obliquely from below onto the foot part of the pendulum stool,

25 shows an alternative embodiment of the foot part with a first embodiment variant of the spring arrangement, 26 shows a next embodiment of the foot part with an embodiment variant of the spring arrangement in which foot elements bear against elastomeric material,

27 is a perspective view of the holding arrangement with elastomer spring viewed obliquely from below,

28 is a view of an axial section through the leg tube and the holding arrangement,

29 is a perspective view of a foot part obliquely from above with a further embodiment of the return spring,

30 is a sectional view of a detail of the embodiment according to FIG. 7,

31 is a view of the section A - A in Fig. 8,

32 shows a schematic illustration of a next embodiment of the spring arrangement,

33 shows a schematic illustration of a further embodiment of the spring arrangement,

34 is a schematic illustration of a next embodiment of the spring arrangement,

35a shows an illustration of an alternative detail of the embodiment according to FIG. 11,

36 shows a schematic illustration of a next embodiment of the foot part and spring arrangement,

37 shows a schematic illustration of a next embodiment of the spring arrangement,

38 shows a schematic illustration of a further embodiment of the spring arrangement,

39 shows a schematic illustration of a further embodiment of the spring arrangement, 40a is a schematic representation of a further embodiment of the spring arrangement,

41b is a perspective view of the embodiment according to FIG. 16a,

42 shows a schematic illustration in section of a further embodiment of the spring arrangement,

43 shows a perspective view of the embodiment according to FIG. 17,

44 shows a schematic illustration in section of a further embodiment of the spring arrangement with a spring washer,

45 shows a perspective view of a spring washer according to FIG. 19,

46 shows a schematic illustration of a further embodiment of the spring arrangement with stopper,

47 shows a schematic illustration of a further embodiment of the spring arrangement with stopper,

48 shows a schematic illustration of the embodiment according to FIG. 22 with the stopper in the functional position,

49 shows a schematic illustration of a further embodiment of the spring arrangement with stopper,

50 shows a schematic illustration of a further embodiment of the spring arrangement with stopper on the leg tube,

51 shows a schematic illustration of a further embodiment of the spring arrangement with stopper and erecting mechanism, and

52 shows a schematic illustration of a next embodiment in which a partial element of a foot element is arranged pivotably.

Detailed description :

In the figures, the same reference numerals are used for the same elements used unless expressly stated otherwise.

Advantageous embodiments of the invention are described below, which are exemplary embodiments. These include various forms of the overall invention, as well as assemblies and individual parts of the invention. In principle, the assemblies and individual parts of the various embodiments described can be combined with one another, or the assemblies and individual parts of individual embodiments can be replaced by the assemblies and individual parts of other embodiments. The combinations formed here may require minor adaptations which are familiar to a person skilled in the art and are therefore not described further, for example in order to enable the assemblies and individual parts to interact or interlock.

In the following, the so-called spring-soft, elastic foot elements are mentioned several times. According to the invention, these are spring-elastic, elastically mounted foot elements with a restoring element and / or foot elements that have a resilient and restoring effect due to their own elasticity. The elasticity of the foot elements can be achieved by a suitable choice of material, the combination of different materials and / or by the shape.

[0035] In the following, so-called support elements are mentioned several times. ^"" In the present context, these are elements that can be attached to the foot of a chair and that can be easily moved or moved along a base. Sliding feet or other sliding elements and rollers are particularly suitable as support elements. Preferably elements are used as sliding elements, the sliding surface of which is adapted to the nature of the standing surface. If the chair is to be used on a carpet, for example, the sliding surface is provided with an appropriate layer that allows it to slide on the carpet. A Teflon or nylon coating is particularly suitable. In the case of a smooth standing surface (parquet, stone floor, or the like), another sliding surface is preferably used, for example plastic or felt.

In the following, instead of support elements, various roles are specifically mentioned. In this context, the term roller is understood to mean a wheel or a roller that can rotate about a wheel axis. Rolls that are rounded are particularly advantageous. Twin roles are also called roles. Before different embodiments of the invention are described, the various movement sequences that can arise in conventional chairs are first discussed. This lays the foundation for understanding the complex dynamic relationships that are used in a targeted manner in some of the chairs according to the invention, whereby according to the invention - as will be described - various effects and movements overlap in a complex manner and only with appropriate dimensioning, respectively configuration occur at all. The various effects and movements interact positively, as will be explained in connection with the various embodiments.

The behavior of a conventional office chair is shown in FIGS. 1A to IC. The detail of a foot element 4 of a star-shaped base (foot part) is shown. At the free end of the foot element 4, a wheel suspension 6 is arranged which carries a roller 8. In the simple example shown, the wheel suspension 6 comprises a fork 6.1 with a receptacle 6.3 (for example a borehole) for a guide pin 6.2. The guide pin 6.2 is in turn seated in a receptacle 6.4 which is provided in the foot element 4. A sleeve is typically inserted into the receptacle 6.4. However, this sleeve is not shown in the figures for the sake of simplicity. The guide pin 6.2 defines a guide axis 6.5, which in the example shown runs perpendicular to a standing surface 9. There is a small offset between the guide axis .6.5 and the wheel axis 8.1, which is referred to here as eccentric bearing.

If the chair is now pulled in the positive X direction, the roller 8 runs behind the foot element 4, as shown in FIG. 1A. The roller turns clockwise as shown by arrow 8.2. If the chair is moved in the opposite direction, i.e. parallel to the negative X-axis, the state shown in FIG. 1B, in which the roller 8 runs ahead of the foot element 4, results briefly. The roller rotates counterclockwise as shown by arrow 8.2. However, this condition is unstable. The roller 8 has the tendency to reverse immediately as soon as a small “disturbing” force acts on the roller from the side. The roller then swings out of the pushed state (FIG. 1B) into a position that is indicated in FIG. IC. This effect can be observed in conventional office chairs. In principle, this behavior is similar to the behavior of a truck, in which a trailer is pushed backwards by a towing vehicle.

Another conceivable variant of a chair is shown in Figures 2A and 2B. The variant of the chair shown differs essentially from the chair of FIGS. 1A to IC that the guide axis 6.5 is inclined. If the chair is now pulled in the positive X direction, the roller 8 follows the foot element 4, as shown in FIG. 2A. The roller rotates clockwise as shown by arrow 8.2. This position is relatively stable since the virtual starting point AI is closer to the stand area 9 than in the arrangement in FIGS. 1A to IC. If the chair is now moved in the opposite direction, ie parallel to the negative X-axis, the state shown in FIG. 2B results, where the roller 8 runs behind the foot element 4. In order to assume this state, however, resistance to gravity must be overcome, since the distance A between foot element 4 and

Stand area 9 must enlarge. In order to move from the position shown in FIG. 2A to the position shown in FIG. 2B, the roller 8 must rotate 180 degrees around the guide axis 6.5. The virtual approach point AI is shifting upwards. This effect is exaggerated in Fig. 1B. If the inclination of the guide axis 6.5 with respect to the vertical position is slight, a small disturbance (for example an unevenness of the standing surface 9 or an asymmetrical load) is sufficient to trigger a rapid movement into the position shown in FIG. 2A. An increasing inclination of the guide axis 6.5 with respect to the vertical position leads to a continuous deterioration of the all-round rotatability (rotation about the guide axis 6.5) of the roller 8, since the resistance to gravity has to be overcome. Depending on the type of rollers and depending on the inclination and the offset between the guide axis 6.5 and the wheel axis 8.1, there are two eccentric effects which can be more or less pronounced. As described, the first eccentric effect is shown as an enlargement of the distance A. The second eccentric effect occurs because the rollers “tip” over the edge when they snap around. The second eccentric effect occurs the more the angularly the rollers are designed Twin roles show this effect less strongly.

As shown in a highly schematic manner in FIG. 3, in the extreme case shown (the guide axis 6.5 runs parallel to the ground 9 and intersects the wheel axis 8.1), the roller 8 can no longer snap around. The flatter the guide axis 6.5 is, the closer one approaches this extreme case.

Another extreme case is that in which the guide axis 6.5 is arranged vertically above the wheel axis 8.1 and the two axes intersect. The change of direction is only possible continuously because the rollers do not adjust in the direction of travel. This case is not shown in the drawing. The chairs previously described in connection with Figures 1A to IC and 2A, 2B have arrangements of the roles, in which the inclination of the guide axes is rigid with respect to the footprint.

In order to provide a chair that responds to the situation, the foot part of the chair is designed according to the invention such that it acts resiliently when loaded. This effect can be achieved either by resilient, elastic mounting of the foot elements, or by the fact that the foot elements themselves have a resilient effect. A combination of both effects is also possible.

In other words, it is important that a foot part according to the invention is at least partially movable and / or feather-soft. For this purpose, such a chair can have, for example, movably mounted foot elements (chair legs), spring-elastic foot elements (chair legs) or a combination of such foot elements.

Support elements are provided on the foot part, which can shift relative to the base when the foot elements move and / or deform. For this purpose, such a chair can have, for example, gliders or rollers on movably mounted foot elements (chair legs), on resilient foot elements (chair legs) or on a combination of such foot elements.

In the following, embodiments of the invention are primarily described in which roles serve as support elements, this focus on role-based embodiments not to be interpreted restrictively.

In order to provide a chair that reacts to the situation, the position (inclination) of the guide axes of the rollers is made changeable in preferred embodiments of the invention. The change in the position (inclination) of the guide axes of the rollers is achieved by the resilient, elastic mounting of the foot elements (chair legs), or by the elasticity of the legs themselves, or by the movable, elastic mounting of the guide pins of the rollers in the foot element. The chair is designed so that it assumes or strives for the following conditions:

(1) in the unloaded state, the guide axes of the individual roles of the chair are steep, preferably almost perpendicular to the standing surface or slightly inclined to cause an initial blockage; (2) In the loaded state, the guide axes of the individual roles of the chair are flat (in the sense of positively inclined), ie the angle of inclination is greater than in the unloaded state.

This situation-dependent inclination of the guide axes 5 reduces the degrees of freedom of the roller system, which has the consequence that coordinated running of all roles of such a chair according to the invention is impossible. When the chair is loaded, the otherwise coordinated running direction of the individual rollers is released and the interplay of at least two rollers results in a braking effect. This braking effect occurs without the need for a braking medium that brakes the rollers individually. As a result of this braking effect, the chair is braked as a whole and can no longer be moved in relation to the footprint.

However, the individual roles 8 of the chair 1 are still movable - that is, unchecked - and can roll radially to a central axis 11 of the chair 1 15 to enable a (resilient) up and down movement of the chair 1, as in the Figures 4A to 4D indicated schematically. Dynamic sitting is thus still possible according to the invention, even if the braking effect occurs, as described.

If sliding elements made of support elements are used, these can also be aligned radially to a central axis of the chair.

According to the invention, the guide axis and the wheel axis of a roller suspension are related to one another in such a way that the roller changes from a so-called unstable position to a so-called stable position when the chair is loaded. This transition is referred to herein as the plunge movement. This immersion

25 gung can be clearly felt on the chair, depending on the design, and includes a rolling and swiveling movement of the castors (double eccentric effect). A roller performs a small rolling movement around the wheel axis during the immersion movement and the roller swivels about 180 degrees around the guide axis. When swiveling around the guide axis, the roller tilts over one of its edges, making the transition

Define 30 of the tread in the side wall of the roller. These effects have already been described in connection with FIG. 2B.

The effects mentioned, which occur when the rollers move from one position to another, more stable position, are influenced by various parameters, which, however, essentially either support or reduce the effects. weaknesses. One example is the shape of the rolls. If cylindrical rollers or twin rollers are used, the cylinder axis of which corresponds to the wheel axis, reversing the rollers is more difficult depending on the dimensions. Thinner rollers or spherical rollers, on the other hand, can be pivoted more easily around the guide axis, since their running surface has a smaller extent parallel to the wheel axis. Another parameter is the eccentricity (initially referred to as offset), ie the distance between the guide axis 6.5 and the wheel axis 8.1. Another way to influence the effects mentioned is by storing the rollers. Smooth-running castors follow the movements of the chair faster and you can give the chair agility in its behavior. The behavior can be dampened by slightly braking the rollers. The chair behaves less aggressively.

The same applies to sliding elements with good sliding properties that they follow the movements of the chair faster and more easily. Sliding elements that slide less well lead to a chair that behaves less aggressively.

It results - depending on the arrangement and depending on the choice of the individual parameters of the support elements and their suspension / storage (such as eccentricity, roller size, frictional resistance, geometry and nature of the surfaces and the footprint, etc.) - a distorting effect the movement behavior described.

It is regarded as a further essential element of the invention that the support points of the support elements of the chair shift radially outwards when viewed from a central axis of the chair and thereby increase the radius of the support surface. This automatically leads to an increase in the stability of the chair.

This outward displacement is counteracted by a restoring force, which can come about in various ways. In the case of rigid foot elements 4 (legs) which are movably attached to a central column 3 of the chair 1, a restoring force can be generated by attaching spring elements. Tension, leaf, torsion or compression springs can be used to

Apply resetting force. But it is also conceivable that the foot elements 4 are mounted elastically. An elastic mounting leads to a restoring force when the chair 1 is loaded, which acts on the respective foot element 4.

However, the restoring force can also result from the fact that the foot elements 4 themselves, or partial elements thereof, are resilient. A foot element can have a resilient effect due to its shape and / or the materials used. Typically, the foot elements 4 or partial elements thereof deform when the chair 1 is loaded. With increasing deformation there is a force (restoring force) which counteracts the deformation.

The restoring force can also result from a combination of several of the effects mentioned.

Details of a first embodiment are described in connection with FIGS. 4A to 4D. 4C shows a schematic plan view of a chair 1 which has only four rollers 8 which are arranged in a star shape with respect to a vertical axis 11 of the chair 1. The chair 1 is shown in an unloaded state in FIG. 4C. The chair 1 defines by the support points of the rollers 8 with the base 9 a support surface, which is indicated by a circle with the diameter AI. Figures 4A and 4B show a sectional view that intersects two of the four rollers 8, which lie in the plane of the drawing. The two rollers 8 each have a fork 6.1 with a guide pin 6.2. The pin 6.2 defines the guide axis 6.5. The guide axes 6.5 of all rollers 8 intersect in the vertical axis 11 when the load is centric. The guide axes 6.5 are set relatively steep in the state shown in FIGS. 4A and 4C. In this state, the angle of inclination β is typically between 0 and 30 degrees and preferably between 0 and 10 degrees. Depending on the embodiment, however, it is also conceivable for the guide axis 6.5 to have a negative angle β in the unloaded state. With vertical pressure in the direction of the axis 11 from top to bottom, the elastic foot elements change the negative angle β via a zero position into a positive angle β. Due to the elastic legs, the guide axes 6.5 move away from the vertical axis 11 with increasing vertical pressure on the base 9. The negative angle β can be between -5 degrees and 0 degrees. If the angle β is set negatively in the unloaded state, there is a braking effect (called initial blocking) of the chair 1. In addition, the negative surface of the rollers 8 reduces the contact area, since all the rollers 8 are directed in a star shape inwards. If the eccentricity, ie the offset between the guide axis 6.5 and the axis of rotation 8.1, is increased, the angle β of the wheel 8 also increases. If the chair 1 is now loaded centrally, as indicated by the arrow 10 in FIG. 4B indicated, the rollers 8 move radially outwards, as can be seen from the enlarged circle in FIG. 4D. Such a lowering movement of the chair 1 combined with a spreading movement of the foot part of the chair 1 is possible without any problems, since the four rollers 8 can run outwards independently of one another on radially directed tracks. As a result, the contact area is enlarged (A2 is larger than AI), which results in increased stability of the chair 1. The enlargement of the contact surface is an important characteristic of the chairs according to the invention. It should be noted that when the chair 1 is loaded asymmetrically, an oval or different shape of the support surface A2 results.

Due to the spreading movement described, load surges can be absorbed by rolling the rollers 8 apart and an up and down movement is possible. Such a spreading movement occurs analogously when sliding elements are used.

Prerequisite for the inclination of the guide axis (s) of the rollers are resilient, elastic mounted legs with restoring force, or resilient legs.

According to the invention, there are the following approaches to achieve a situation-dependent inclination of the guide axis (s) of the rollers:

(1) The rollers 8 are suspended on the foot elements 4 in such a way that the guide axis 6.5 of each individual roller 8 can incline in relation to the foot element 4 depending on the load (see FIGS. 5A and 5B);

(2) The suspension of the rollers 8 on the foot elements 4 is rigid, but the foot elements 4 are movably attached to the chair 1 in such a way that a movement of a foot element 4 changes the inclination of the guide axis 6.5 with respect to the base 9 ( see Figures 6A and 6B);

(3) The suspension of the rollers 8 on the foot elements 4 is rigid, but the foot elements 4 are flexible and in such a way that a deformation of the foot elements 4 changes the inclination of the guide axes 6.5 with respect to the base 9 (see FIG. 7A and 7B);

(4) A combination of one or more of the above approaches.

Details of a second embodiment are described in connection with FIGS. 5A and 5B. A schematic side view of a chair 1 is shown. The chair 1 is constructed essentially mirror-symmetrically. The For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat (not shown) and a central column 3 which is rigidly connected to the foot elements 4. For example, a rigid base with three, four or five base elements 4 can be provided. However, a disk, ring or cup-shaped foot element can also be used, in the center of which the column 3 is fastened. The column 3 can have a cone at the lower end, which sits, for example, in a central hole of such a base or foot element. The roller 8 is carried by a suspension which comprises a fork 6.1. At the upper end of the fork 6.1, a guide pin 6.2 is arranged, which is tiltably mounted in the foot element 4. If the chair 1 is loaded, it lowers and the rollers 8 execute an immersion movement, as shown in FIG. 5B, in which the guide axis 6.5 inclines by an angle of inclination β. Depending on the load, the guide axes 6.5 tilt to different degrees when the chair 1 lowers. The contact area increases. The inclination of the guide axes 6.5 results in a resilient behavior of the foot part of the chair 1.

Details of a third embodiment are described in connection with FIGS. 6A and 6B. A schematic side view of a chair 1 is shown. The chair 1 is constructed essentially mirror-symmetrically. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat 2 and a central column 3. The height of the seat can be adjusted, for example, as in conventional chairs, by a lifting spindle 13 being mounted in a thread of the column 3. The suspension of the rollers 8 on the foot elements 4 is rigid. However, the foot elements 4 are movably attached to the chair 1 in such a way that a movement of a foot element 4 changes the inclination of the guide axis 6.5 with respect to the base 9. In the embodiment shown, the foot element 4 is pivotally connected to the column 3 at its upper end via a horizontal axis 3.4. This articulation on the column 3 is shown purely schematically. In the unloaded state (Fig. 6A), the guide axis 6.5 of the roller 8 is slightly inclined. The angle of inclination β is preferably between -5 and 10 degrees in the idle state. If the chair 1 is loaded centrally, as shown in FIG. 6B, the rollers 8 move radially outwards. The foot element 4 is deflected, the angle of inclination β becoming larger. This also causes the guide axis 6.5 of the rollers to incline, as can be seen in FIG. 6B. The angle of inclination β can assume an inclination of up to 60 degrees.

In order for this spreading movement of the foot elements 4 to take place in a controlled manner, a reset element is preferably used or an arrangement is selected, which counteracts the spreading movement with a restoring torque. A greatly simplified reset element 12 is indicated in FIG. 6B. It applies a restoring force R to the foot element 4, which is directed radially towards the axis 11. The return element 12 can be used to influence the characteristic of the pivoting movement and it can be prevented that the foot elements 4 are spread completely and the lower end of the column 3 of the chair 1 is placed on the standing surface 9. The movement behavior of the foot elements 4, which is predetermined by the type of suspension and the provision of restoring elements, is referred to as resilient.

6A, 6B, the foot part of the chair 1 has at least three foot elements 4 and a central column 3, each of the foot elements 4 being suspended mechanically with respect to the column 3 in such a way that the foot elements 4 when the chair is loaded 1, as described in connection with FIGS. 6A and 6B, execute a pivoting movement and move radially apart. The base elements 4 are preferably subjected to a restoring force R.

In such an embodiment, preference is given to a rigid suspension of the rollers 8 on the foot elements 4, in which they can rotate about the guide axis 6.5, but their inclination with respect to the foot elements 4 does not change. Such an embodiment, as shown in FIGS. 6A, 6B, can be modified in that the guide axis 6.5 is also tiltably mounted, which leads to a superposition of two tilting movements when the chair 1 is loaded. This also changes the resilient effect.

Details of a fourth embodiment are described in connection with FIGS. 7A and 7B. A schematic side view of a chair 1 is shown. The chair 1 is constructed essentially mirror-symmetrically. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat (not shown) and a central column 3. Foot elements 4 are provided which are rigidly connected to the column 3. The suspension of the rollers 8 on the foot elements 4 is rigid. If the chair 1 is loaded centrally, as shown in FIG. 7B, the rollers 8 move radially outward, since the foot elements 4 are subject to deformation. Depending on the rigidity of the foot elements 4, this deformation can be more or less pronounced. Instead of providing several individual foot elements 4, a disk-shaped, ring-shaped or cup-shaped foot element 4 can also be used, this element 4 being designed to be elastic. In this embodiment, the resilient effect essentially results from the elastic deformability of the foot elements 4. In FIG. 7A, the angle of inclination β was approximately 0 degrees. When loaded, the angle of inclination β increases, as indicated in FIG. 7B. With elastically deformable foot elements 4, changes in the angle of inclination β between -5 and 30 degrees can be generated. The angle of inclination is preferably between -5 and 10 degrees.

Another embodiment is shown in FIGS. 8A and 8B. A schematic side view of a chair 1 is shown. The chair 1 is constructed essentially mirror-symmetrically. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat (not shown) and a central column 3. A disk-shaped elastic foot element 4 is provided, which is rigidly connected to the column 3. The column 3 is in the example shown with its lower end, which is preferably conical, in the foot element 4, as indicated schematically by a dashed line. The suspension of the rollers 8 on the foot element 4 is rigid. If the chair 1 is loaded centrally, the rollers 8 move radially outwards, since the foot element 4 is subject to deformation. Depending on the rigidity of the foot element 4, this deformation can be more or less pronounced. The foot element 4 can also be made ring-shaped or pot-shaped.

[0074] The chair! asymmetrically loaded, the foot element 4 deforms and the guide axis 6.5 of the roller 8 tilts with respect to the standing surface 9, as shown in detail in FIG. 8B. The angle of inclination ß is between 0 and 30 degrees when chair 1 is loaded. The angle of inclination is preferably between 0 and 10 degrees. The spring-elastic effect in this embodiment results essentially from the elastic deformability of the foot element 4.

Another embodiment is shown in FIG. 9. A chair 1 is shown which comprises a foot part which comprises a vertical column 3 and a foot element with six legs 4. A roller 8 is attached to each of the six legs 4, each of the rollers 8 being mounted such that it can roll about a wheel axis 8.1 of a suspension and is freely rotatably connected to the respective leg 4 via a guide axis 6.5. The suspension of the rollers 8 is rigidly connected to the legs 4, ie the rollers 8 and their suspension can rotate about the guide axis 6.5, but the inclination of the guide axis 6.5 with respect to the legs 4 cannot be changed. The embodiment shown is characterized in that the Legs 4 are suspended mechanically in relation to the column 3 in such a way that when the chair 1 is loaded they execute a pivoting movement and move radially apart. The bearing comprises an elastic ring element 4.1, which is arranged at the lower end of the column 3. The legs 4 extend radially through the ring element 4.1. The mechanical suspension of the legs 4 is protected by the ring element 4.1 and the ring element 4.1 brings about a restoring force on the legs 4. When the chair 1 is loaded, at least one of the rollers 8 automatically executes an immersion movement in which the guide axis 6.5 of this one roller 8 their inclination ß changes with respect to a footprint. As a result, at least one contact point of the chair 1 is shifted outwards.

The chair 1 according to FIG. 9 is shown in an unloaded state and the rollers 8 assume a position in which the guide axes 6.5 are substantially vertical or, if an initial blocking is desired, are inclined slightly negatively. Due to the vertical or slightly negative inclination, the degrees of freedom of the rollers 8 are not significantly restricted and the rollers 8 easily follow every movement of the chair 1.

In this embodiment, the resilient effect essentially results from the special elastic mounting of the legs 4.

Preferably, the legs 4 are made of a plastic, ideally from - a fiber-reinforced plastic, - or from die-cast aluminum. However, production from other materials, such as wood, is also possible. An elastic effect can also be achieved by a suitable combination of materials or by a suitable shaping.

In a preferred embodiment, a seat 2 and a backrest 2.2 are provided, which is attached with a holder 2.1 below the seat 2.

In addition or as an alternative, the legs 4 themselves can be designed to be elastically deformable. The deformability can be achieved, for example, by a lateral torsion of the axes of the legs 4. Preferably, the restoring force can be adjusted via a spring element (for example a spring), which is attached to the column 3, which acts on the legs 4 of the chair 1. Such a spring 14 is shown in FIG. 9. This spring 14 is optional. By means of such a spring, the degrees of freedom of the movement can be influenced by influencing an elastic element in the area of the column 3 is ordered to be checked.

Details of a further embodiment are shown in FIGS. 10A and 10B. Fig. 10A is a side view of the foot part of a chair and Fig. 10B is a section along the line AA. The chair has a central column 3, which in the example shown comprises a gas pressure spring of conventional design. The gas pressure spring consists of elements 3.1, 3.2 and 3.3. The height of the seat of the chair can be adjusted using the gas pressure spring. A total of five curved legs 4 are provided. A roller 8 is attached to each of the five legs 4, each of the rollers 8 being mounted such that it can roll about a wheel axis 8.1 of a suspension 6.1 and is connected to the respective leg 4 in a freely rotatable manner via a guide axis 6.5. The suspension 6.1 of the rollers 8 is rigidly connected to the legs 4, ie the rollers 8 together with their suspension 6.1 can rotate about the guide axis 6.5, but the inclination of the guide axis 6.5 with respect to the legs 4 cannot be changed. The embodiment shown is characterized in that the legs 4 are suspended mechanically with respect to the column 3 in such a way that they carry out a pivoting movement when the chair is loaded and move radially apart. The bearing comprises a ring element 4.1, which is arranged at the lower end of the column 3. Each of the legs 4 is seated in a sleeve 4.2, as can be seen in FIG. 10B. A separate pivot axis 4.3 is provided for each of the legs 4. These pivot axes 4.3 are preferably arranged tangentially to the cylindrical circumference of the column 3 and run perpendicular to the central axis 11 of the chair. In the embodiment shown, the ring element 4.1 has an upper ring 4.4 and a lower ring 4.5. An elastic ring element 4.6 is arranged between these two rings, which exerts a restoring force on the ends of the legs 4 if the legs 4 are pivoted about the pivot axes 4.3. The restoring force arises from the fact that when a leg 4 is pivoted, part of the elastic ring element 4.6 is compressed (deformed). Optionally, the degrees of freedom of the movement can be controlled by influencing the elastic ring element 4.6 by means of a spring or disk. Such influencing can be implemented, for example, in such a way that the elastic ring element 4.6 cannot deform or can only deform upwards to a limited extent when loaded by one of the legs 4. The rollers 8 are seated in a suspension which is fork-shaped, as can be seen in Fig. 10B. The bearings of the rollers 8 are also eccentric here, ie the guide axes 6.5 and the wheel axes 8.1 do not intersect. In this embodiment, the resilient effect essentially results from the special mounting / suspension of the legs 4. Another embodiment of movably mounted chair legs 4, which can be used advantageously in connection with the present invention, is shown in different views in FIGS. 11A-11E. The rollers are not shown in Figures 11A-11E. 11A is a perspective view of the foot part of a chair. The chair has a foot part with five legs 4 and a central column 3. 11B shows a partial section through a lower region of the chair. 11C shows a top view of the foot, in which the radial arrangement of the legs 4 can be seen. Each leg 4 is individually connected to an annular element 4.1 via a mechanical suspension 4.7. FIG. HD is a section along line AA and FIG. HE is a section along line CC. Details of the mechanical suspension 4.7 can be seen in these sectional representations. Each of the legs 4 is articulated to the ring-shaped element 4.1 via a tensioning element 4.7, for example in the form of a steel cable. The tensioning element 4.7 is seated in an elastic sleeve, which is shown in dark gray in the figures. Depending on the tension of the clamping element 4.7, the "elasticity" of the suspension can be adjusted.

Due to the ring element 4.1 and the special design of the tensioning elements 4.7, a restoring force acts on the legs 4. In this embodiment, the resilient effect essentially results from the special positioning / suspension of the legs 4.

The legs 4 are preferably made of a plastic, ideally of a fiber-reinforced plastic, or of die-cast aluminum, or of wood.

A section through a further chair 1 according to the invention is shown in FIG. 12A. A schematic side view can be seen in FIG. 12B. The chair 1 has several legs 4 which are mechanically suspended with respect to a central column 3. At the upper end of the column 3, a seat 2 is arranged. The column 3 comprises a spring mechanism, the individual elements of which are not described further here. It should only be noted that by adjusting the hood 14.1, the spring 14.2 can be acted on in such a way that the degrees of freedom of the movement are controlled by influencing an elastic ring element 4.11. Such influencing can be implemented, for example, in such a way that the elastic ring element 4.11 cannot deform or can only deform upwards to a limited extent when loaded by one of the legs 4. The mechanical suspension of the chair legs is carried out as follows. There are elastic elements / segments 4.8 and 4.11 between a lower annular element 4.10 and an upper annular shaped element 4.9 clamped. The annular element 4.9 is preferably designed in such a way that it yields when one of the legs 4 moves upward, as can be seen to some extent in FIG. 12B. The restoring force which acts on the legs 4 can be adjusted by the pressure of the spring 14.2, which acts on the elastic ring element 4.11. The legs 4 are pivotally connected to a supporting part of the column 3. During assembly, the legs 4 can simply be suspended before the lower annular element 4.10 and the upper annular element 4.9 are inserted. Such a connection of the legs 4 to the column 3 can take place, for example, by means of a thru axle or the like. As shown in FIG. 12B, the elastic elements / segments 4.8 and 4.11 form receiving pockets for the legs 4. If a leg 4 is now pressed upwards in relation to the column 3, for example when the chair 1 is loaded by a User, the chair leg 4 presses the element / segment 4.11 together and a restoring force is established. In the example shown, the element / segment 4.11 is provided with an inclined surface 4.12 which points obliquely away from the central axis 11 of the column 3. Depending on the inclination of this surface 4.12, the material of the elastic element / segment 4.11, its thickness and the action of the spring 14.2, the restoring force can be influenced. An elastomer ring 4.11 is preferably used, which is cylindrical in the lower region and conical in the upper region, the conical part defining the surface 4.12. In this embodiment, the resilient effect essentially results from the special mounting / suspension of the chair legs 4.

Further details of such a chair can be found in the aforementioned German patent application DE 10338549.1, which was filed on August 19, 2003 and bears the title "Pendulum Chair".

Another preferred embodiment is shown in FIG. The foot of a chair is shown, which has a central column 3. The chair has six legs 4, four of which can be seen in the view. Each of the legs 4 has an L shape, the L lying and the short leg 4.16 of the L running parallel to the central axis 11 of the column 3. The long leg 4.15 of the L runs essentially parallel to a standing area 9. A plurality of recesses 4.13 spaced apart from one another are provided on the short leg 4.16. The legs 4 are arranged around the column 3 such that an elastic, ring-shaped element 4.14 can encompass the six legs 4 and come to rest in the recesses 4.13. In the embodiment shown, the annular element lies

4.14 seen from above in the second recess. Up and / or down can the legs 4 be clamped by discs 3.4, 3.5 or the like. Depending on the position of, or the number of ring-shaped elements 4.14, one changes the lever arm and thereby the hardness of the setting. The legs 4 can move radially in planes that are perpendicular to the central axis 11. These planes form an angle of 60 degrees with one another if six legs 4 are provided. Optionally, an elastic ring or another elastic body can be positioned between the legs 4 from below. An initial spread of the legs 4 can be predetermined by such an element. In this embodiment, the resilient effect essentially results from the special mounting of the legs 4 and the spring element 4.14.

Alternatively, or in addition, the legs 4 themselves can be elastic and bend under load. In this case, the ring 4.14 can be made inelastic and causes a change in the length of the elastic legs 4 (lever length).

In a further embodiment, the legs 4 are designed so that their length can be changed. The legs 4 can, for example, be telescopically extendable.

Another embodiment is shown in the detailed view of FIG. 14. A central column 3 has a cylindrical extension 3.7 at the lower end, which is arranged concentrically to the central axis 11. Arranged around this cylindrical extension 3.7 is an elastic, bulbous element 3.6, which in the example shown forms a cavity 3.9. The legs are connected to the elastic, bulbous element 3.6, as shown by means of a single leg 4. At the free end of the leg 4, a recess 6.4 is provided for receiving the guide pin of a roller suspension. When the chair is loaded, the element 3.6 deforms and thereby gives the leg 4 the required mobility. Moving the leg 4 changes the angle of inclination of the guide axis 6.5. The element 3.6 can be provided with a valve 3.8, which allows the pressure in the cavity 3.9 to be changed and thereby to influence the spring characteristic of the element 3.6. Instead of a bulbous element 3.6, for example, a cylindrical or another shaped element can also be used. In this embodiment, the resilient effect essentially results from the special suspension of the legs 4.

[0092] In a preferred embodiment, the chair is designed with rollers serving as support elements in such a way that (1) it is braked when not in use so that it does not roll away when the chair is touched or hit. This is achieved in that the guide axis has a slight negative inclination (-5 <ß <0 degrees);

(2) it can roll freely when sitting in a centered position (symmetrical load);

(3) it exerts a braking effect under one-sided loading (asymmetrical loading).

It is common to all of the embodiments that dynamic sitting can be ensured by the resilient effect of the foot part. The movement of sitting in all three dimensions (dynamic sitting) is achieved by the movement of the legs and possibly in combination with the sliding / rolling of the support elements of the chair.

It is common to all roller-based embodiments that the guide axis and the wheel axis of a roller suspension are related to one another in such a way that the rollers change from a so-called unstable position to a so-called stable position when the chair is loaded asymmetrically. Through this

Transition (immersion), the degrees of freedom of the musculoskeletal system of the chair are reduced. This results in the braking effect that distinguishes the chairs according to the invention.

In the case of asymmetrical loading of a chair 1 according to the invention with rollers 8, the rollers 8 automatically assume a position due to the immersion movement, in which at least two of the rollers 8 point in different directions and thereby brake the entire chair 1 with respect to the standing area 9 ,

The effects which the present invention makes use of can be observed particularly clearly if the castors of the chair are not braked per se, since the castors then run freely when the chair is immersed before moving from an unstable to a stable one Reverse position (immersion movement). In addition, the unrestrained roles allow a particularly pronounced dynamic up and down movement.

[0097] To produce the braking effect according to the invention, no silent rubbers, brake pads or brake bells partially encompassing the roller are required. On the contrary, the use of such brake media can possibly suppress the effects according to the invention.

The immersion movement occurs when the angle of inclination, ie the Angle of the guide axis 6.5 with respect to the vertical chair axis 11, changed depending on the load on the chair 1.

Preferably, the angle of inclination β of the guide axes 6.5 of the rollers 8 with respect to the vertical axis 11 is between -5 and 30 degrees. An angle of inclination β between -5 and 10 degrees is particularly advantageous. With rounded rollers 8 (as shown, for example, in FIG. 12A), the angle of inclination β can be smaller than with rollers 8 or rollers, the edge regions of which are less rounded.

Chairs with any number of legs can be realized. Typically between three and six legs are used.

In a further embodiment, which is not shown in one of the figures, since it can be a variant of the different embodiments, the chair is designed so that it is assigned a defined seating direction. This can be, for example, achieved in that the seat surface ge ^¬ genüber the base of the chair, of the elements 3, 4, 6 and 8 comprises, can not be rotated. For this purpose, for example, the seat 2 can be guided with a vertical groove in the column 3, which allows a vertical up and down movement but no rotation about the vertical axis 11. If the seat direction is determined, the resilient effect of the foot elements 4 can be set differently at the front than at the rear. This makes it easier to rock the chair forward than backward, for example.

A further embodiment is characterized in that an adjusting means 15 is arranged between the vertical column 3 and the legs 4, the starting points of which can be moved vertically along the column 3 and / or horizontally along the legs 4, as in FIG. 15 schematically indicated by double arrows. Depending on the position of the starting points, this allows the initial spread to be set and / or the strength of the tension to be set. The length of the adjustment can preferably be changed by means of 15 or the hardness / elasticity thereof and slots 15.1, 15.2 are provided for displacement. In the area of the attachment points, the adjustment means 15 can be fixed by means of screws or the like, for example, after being moved. Such an adjustment means 15 can also be integrated into the column 3 in order to reduce the risk of injury by pinching.

Another embodiment is shown in FIG. 16. You can see one Perspective view of a foot part 5. An embodiment of a spring arrangement for the foot elements 4 is shown. In this embodiment, the foot elements 4 engage a spring steel ring 20 by means of slots or the like. The spring steel ring 20 is placed over an annular extension of an elastomer spring 17 which has a disk-shaped element 18 towards the top. In this embodiment, a washer can be provided which covers the elastomer spring 17 and the spring steel ring 20 from below. The washer can be secured, for example, by means of a screw connection to the leg tube 15, which is part of a column 3, or to a leg tube. In this embodiment, the resilient effect essentially results from the special suspension of the legs 4. The legs 4 per se can be rigid or inherently resilient.

17 shows a further embodiment of a spring arrangement for the foot part 5. In this embodiment, the spring arrangement 17 is designed as a leaf spring arrangement in which one or more leaf springs 19 are arranged in the foot elements 4. 17, four leaf springs 19 of different lengths are schematically assigned to a foot element 4. The design, shape and number of leaf springs 19 are at the discretion of the person skilled in the art, since these are adapted to the corresponding needs. The construction shown can be provided for fastening from a bolt plate 24 with a tensioning disk 25. Here, the bolt plate 24 clamps together with its upper flange 24 'and the lower clamping disk 25 the inner end of the leaf springs 19. At the free end of the bolt 24 "there is a thread onto which a nut is screwed in order to apply the necessary holding force. The entire package can have a foot element 4 in a hollow configuration. This makes it possible to make the leaf spring arrangement 19 in plastic or In this embodiment, the resilient effect essentially results from the special embodiment of the legs 4, which act in a resilient manner.

Fig. 18 shows an arrangement in which a conical leaf spring 19 is completely cast in a foot element 4 of plastic material with elastic properties. In this embodiment, the resilient effect essentially results from the special embodiment of the legs 4, which act in a resilient manner.

Fig. 19 shows a next embodiment in which the foot element 4 is held by means of a joint 26 on a joint bearing element 27 at the lower end of the leg part 3. In this embodiment, a slit 16 of the Fus ^¬ selements 4 engage over a resilient ring, which for simplicity is not shown. In this embodiment, the resilient effect essentially results from the special suspension of the legs 4. The legs 4 per se can be rigid or inherently resilient.

[00107] A next embodiment is shown in FIG. 20, in which the articulated struts 26 are replaced by one or more springs 26 '. In this variant, the foot element 4 can overlap a bearing with a slot, for example, as shown in FIG. 12A, an axle bolt 14 'which can be held stationary or movable by means of a suspension 14 ". The cover cap 17 can prevent jamming. The spring-elastic effect in this embodiment results essentially from the special suspension of the legs 4. The legs 4 per se can be rigid or inherently spring-elastic.

A next embodiment is shown in Fig. 21. Here, a restoring force is generated by compression springs 19 which are arranged between a vertical leg of a foot element 4 and a leg tube 3. During a pivoting movement, the compression spring 19 is compressed and thus generates a restoring force. In this embodiment, an elastomeric material can also be used instead of a compression spring. In this embodiment, the resilient effect essentially results from the special suspension of the legs 4. The legs 4 per se can be rigid or inherently resilient.

22 shows a further embodiment of the invention: In this embodiment, the foot element 4 is divided into a movable part 4 'and a rigid part 4 ". The movable part 4' is articulated on the rigid part 4" arranged. A spring arrangement 19 is formed between the two tiles 4 'and 4 ". In the example shown, a joint 44 is provided on the underside of the foot element 4, which serves as a hinge between the movable part 4' and the rigid part 4". The mutually opposite surfaces of the parts 4 'and 4 "together form a V-shaped cutout in which the compression spring 19 is inserted. When the chair 1 is loaded, the movable part 4' pivots against the spring force of the compression spring 19 and experiences it The resilient effect in this embodiment results essentially from the special embodiment of the legs 4, which act in a resilient manner.

According to the invention, the offset between the guide axis 6.5 and the wheel axis 8.1, which is referred to here as eccentric bearing, is typically between 0.5 cm and 5 cm. An offset between between 1 cm and 3 cm. The choice of the appropriate offset is important since the inventive effects of the braking effect do not occur if the offset is too small or too large. If the offset is too large, safety problems can occur, in particular if the guide axes have a negative inclination β which is too large, since in this case the rollers are too close to one another in the unloaded state. Rolls with a diameter between 1 and 8 cm are particularly suitable. Rolls with a diameter between 2 and 5 cm are particularly advantageous.

Depending on the embodiment and choice of the various parameters, a synergistic effect results from the positive interaction of the individual components of the chair. The individual components of the chair are the springy legs, for example caused by the effect described in connection with the drawings 5A, 5B, 6A, 6B, or 7A, 7B.

In addition, a chair according to the invention can have support elements (for example rollers) which only show the braking effect described by the spring-elastic legs.

[00113] A chair according to the invention not only exhibits the braking effect described if rollers are used, but it generally increases its contact surface when loaded and it enables almost frictionless and secured movement up and down due to the running ability of the rollers or the sliding ability of the sliding elements parallel to the vertical axis 11. Through the combination and interaction of these effects, a chair can be provided that meets all requirements in terms of safety, dynamism, health and comfort.

Fig. 23 shows in an axial sectional view a further embodiment of a pendulum stool 1 with a seat part 2, a leg part 3 and with foot elements 4, which protrude radially from a foot part 5. Three such foot elements 4 can be seen in the illustration. In implemented embodiments, any number of such foot elements can be arranged on a foot part, between four and six are usual. A spring arrangement 6 is attached to the leg part 3, which enables the seat part 2 to swing up and down on the foot part 5. In the embodiment shown, the foot elements are provided with rollers 8 at their free ends. However, this is a variant that is not mandatory is because there are also pendulum stools that stand on sliding buttons. The foot part 5 arranged in the lower region of the leg part 3 has a holding arrangement 10, on which the foot elements 4 are essentially suspended individually and are mounted so that they can be swiveled up and down.

In the foot part 5, a second spring arrangement 9 is provided, which cooperates with the holding arrangement 10. In the exemplary embodiment shown, the holding arrangement 10 has holding segments 10 ′ distributed over a circumference of 360 °, which define a free cross section and are at a distance from one another. The spring arrangement 9 consists in the illustrated embodiment of an elastomer ring inserted into the free cross section, which is in the lower

The area is cylindrical and the upper area is flared outwards. For this purpose, the holding segments 10 'have a corresponding conical flattening. An axle bolt 14 is installed in the space between the segments 10 ', on which, as will be explained in more detail later, the foot elements 4 can be hooked on. The lower part of the leg part 3 is inserted into the free opening cross section of the elastomer ring in the foot part 5 and is connected to the foot part by a closure piece 13 on its side facing the floor.

In the embodiment shown in FIG. 23, the leg part has an abutment plate 11 on which the first spring arrangement 6 can be supported. This abutment plate is fixed to the tube 10 of the leg part 3.

The spring force of the spring arrangement 6 can be adapted to a user by means of the adjusting device 7. In the spring arrangement used in connection with the exemplary embodiment according to FIGS. 26 and 28, this adjusting device 7 also serves to adapt the restoring force to the extent of the desired pendulum movement.

24 shows a pendulum stool in a perspective view obliquely from below. One thus looks at the foot part 5 with the closure piece 13 from below.

25 shows a schematic representation of the arrangement of foot elements 4. In the foot elements 4, slots 16 are formed at the ends on both sides, which open downwards. With this slot 16, the foot elements 4 are suspended on the axle pin 14. The inner end faces of the foot elements 4 are provided with a bevel 4 'with which they bear against the conical outer surface 9' of the molded cone of the spring element 9. At a predetermined distance above the back of the foot elements 4, a cover cap 17 made of resilient material is arranged material. Rollers 38 are provided under the cap, against which the backs of the foot elements 4 rest and roll along during their pivoting movement. Since the cover cap 17 is essentially translationally fixed in the axial direction of the leg part, it exerts a restoring moment on the respective foot elements 4 when they perform an upward pivoting movement.

Fig. 26 shows a further embodiment of a spring arrangement 9. In this arrangement, the spring arrangement 6, which is mainly responsible for the up and down movement of the stool, also provides the spring forces for the restoring moments that act on the foot elements 4 act. For this purpose, the spring 6 is supported via the plate 11 on a transmission plate 6 'on the ring of holding segments 10'. When a foot element 4 swivels upwards, its inclined surface 4 'presses against the conical spring mass of the ring 9 and urges this material upwards, and the material wants to expand and in turn presses against the transfer plate 6', which is against the abutment plate 11 supports. However, since this abutment plate 11 is spring-loaded, both the restoring force of the spring arrangement made of the material 9 and the force of the spring 6 act on a spring element 4 which is pivoted upward, in order to thus push back the spring element 4 in the original direction. In this embodiment, the abutment plate 11 is axially displaceable along the tube 15 of the leg part 3. The abutment force previously provided by the axial fixed plate 11 is provided by the holding segment assembly 10 in this embodiment.

27 shows a perspective view of the holding arrangement 10 with six holding segments 10 'and an inserted annular elastomeric spring arrangement 9.

The holding arrangement consists, as already explained in connection with FIG. 23, in the illustrated embodiment of ring-shaped holding segments 10 ', each having a predetermined distance, measured in degrees, from each other. A holding arrangement is formed between the individual holding segments, in the exemplary embodiment shown an axle bolt 14. These axle bolts 14, each inserted into the spacing areas, join the holding segments 10 'together to form a retaining ring. At the inner edge, this retaining ring has an inclined surface 10 ″ on the retaining segments 10 ′, which, viewed as a whole, forms a conical bearing surface for the conical upper region 9 ″ of the elastomeric spring ring 9 when viewed as a whole. Accordingly, the egg-elastomeric spring ring 9 in the illustrated embodiment is a single lumpy elastomeric ring formed, which is enclosed in its lower region by the cylindrical sections of the holding segments 10 ', that is to say it bears against the cylindrical section of the holding elements 10' and has a conical extension in the upper region which rests on the conical surfaces 9 '.

In the embodiment shown in Fig. 26, the plate 6 'is essentially designed in diameter so that it rests in the region of the upper inner edges of the holding segments 10'.

On the other hand, in the embodiment shown in FIG. 28, in which the tube arrangement of the leg part 3 and the foot part 5 are shown in sectional detail, the support surface of the spring 6 is on the rubber-elastic material of FIG

Spring arrangement 9 much lower. The diameter of the transmission plate 6 'is slightly smaller than a recess in the abutment plate 11 located above it. In the abutment plate 11 there is a bore, the clear width of which is dimensioned such that the tube 15 of the leg part 3 can pass through and enter with a corresponding load Sitting on the transfer plate 6 'is possible. As a result, the leg part experiences a spring-soft stop position with maximum compression of the spring.

In the case of a pendulum movement, ie a lifting of a foot part (not shown in this example), the elastic material 9 presses upwards and consequently the transmission plate 6 'into the recess in the abutment plate 11. Between the transmission plate 6' and the abutment plate 11 an elasti ^¬ specific intermediate layer may be disposed. This embodiment enables a cardanic mounting of the leg tube, which leads through the elastic ring 9 with a tube extension 15 ′ and is fixed to the mounting on the lower side of the holding arrangement 10 by means of a screw connection 19. Here, a screw connection, not shown, is supported by a washer construction on the holding arrangement 10.

Fig. 29 shows a next embodiment of a spring arrangement for the foot elements 4. In this embodiment, the foot elements engage by means of the slots 16 on a spring steel ring 20. The spring steel ring 20, as can be seen from FIG. 30, is put over the annular extension of the elastomer spring 9 and is flush with the lower edge thereof. In this embodiment, a washer 21 is provided, which covers the elastomer spring 9 and the spring steel ring 20 from below. The washer is secured by a screw on the leg tube 15 or on a leg tube 15 '. On the leg tube 15 'one Locking disc 11 "fixed, which offers an abutment for the alternative elastomeric material 9.

The foot element 4 preferably has a bevel 22 on its lower edge lying between the slot 16 and the end on both sides, which allows the foot element 4 to be pivoted upwards without the washer 21 counteracting it.

In one embodiment, not shown, a radially protruding projection formed on the leg end 4 can be formed on the base element 4, which exerts a substantially vertically downward pivoting force on the elastomer ring 9 instead of with inclined surfaces with a downward-facing surface. In such an embodiment, the elastomer ring 9 can be designed as a simple elastic tubular sleeve with a correspondingly thick wall, which absorbs the pivoting force by means of its upwardly directed end wall.

At the points at which a foot element 4 overlaps the steel spring ring 16, a corresponding recess 23 is provided on the elastomer ring in order to allow the steel spring ring 20 to overlap through the slot 16.

31 shows a further exemplary embodiment of a spring arrangement for the foot part 5. In this embodiment, the second spring assembly 9 is as one. Leaf spring arrangement _. in which one or more leaf springs 9 "are arranged in the foot elements. In FIG. 31, four leaf springs 9" of different lengths are schematically assigned to a foot element 4. The design shape and the number of the leaf springs 9 "is at the discretion of the practitioner, since they are adapted to the respective needs. For mounting, the Darge ^¬ presented construction of a stud plate 24 with clamping plate 25 be provided. Here, clamps the pin plate 24 upper with its Flange 24 'and the lower clamping disk 25 together the inner end of the leaf springs 9 ". A thread is provided on the free end of the bolt 24 ″ onto which a nut is screwed in order to apply the necessary holding force. The entire package can be arranged in a hollow shape of a foot element 4. This makes it possible to make the leaf spring arrangement 9 in plastic or in a Embed elastomer.

Fig. 32 shows an arrangement in which a conical leaf spring 9 is completely cast in a foot element of plastic material with elastic properties. Fig. 33 shows a next embodiment in which the foot element 4 is held by means of a joint 26 on a joint bearing element 27 at the lower end of the leg part 3. In this embodiment, the slot 16 of the foot element 4 can overlap a resilient ring; , which is not shown for the sake of simplicity.

A next embodiment is shown in Fig. 33a, in which the hinge struts 26 are replaced by one or more springs 26 '. In this variant, the foot element 4 can overlap a bearing with the slot 16, for example, as shown in FIG. 23, an axle bolt 14 which can be held in a stationary manner or movable by means of a suspension 14 '.

Fig. 34 shows a next embodiment of a spring arrangement 9 on the foot part 5. In this embodiment, the foot elements 4 have essentially the shape of an L with a bottom leg 29 and a vertical leg 29 ', the horizontal bottom leg 29 being longer is as the vertical leg 29 '. In the angular region of the foot element, a spring arrangement 9 is provided, which acts on the one hand on a corresponding holding projection 30 under the horizontal leg of the foot element 4 and on the other hand on the leg part 3. Furthermore, each of the foot elements 4 is pivotally held in this angular range via a suspension 28. During a swiveling movement, the foot element 4 is pressed upwards and rotates around the suspension 28. At the same time, the restoring force exerted by the spring arrangement 9 acts, which causes a moment against the swiveling or oscillating movement of the chair.

All upward legs are covered by the cap 17 and secured against accidental jamming of objects.

In Fig. 35 a variant of the embodiment from Fig. 12 is shown. Here, the restoring moment is not generated by tension springs arranged under the foot elements 4, but rather by compression springs 9, which are arranged between the vertical leg of a foot element 4 and the leg tube 3. With a swivel movement, the tension spring is compressed and thus generates a restoring torque. In this embodiment, an elastomeric material can also be used instead of a compression spring.

36 shows a next embodiment variant of the exemplary embodiment according to FIG. Fig. 34. In this variant, the upstanding legs of the foot elements 4 held at their upper end by means of a suspension 28 '. The restoring spring force is provided by a resilient pull ring 9 '', which is inserted into bearing grooves 31 arranged there on the outwardly directed back of the vertical leg 29 'of the foot element 4. In order to change the strength of the restoring moment, the ring 9'"can be arranged on different levels. The larger or smaller distance from the suspension 28 'results in a larger or smaller restoring torque. The closer the ring is to the suspension 28 ', the lower the restoring torque; conversely, the distance to this suspension increases.

In addition to the elastic ring 9 '", as shown in FIG. 34, a cap 17 made of an elastic material can bring about a resilient restoring moment if, in the exemplary embodiment according to FIG. 36, it extends over the legs 29 projecting upwards the foot elements 4 are screwed in. When a foot element 4 is deflected, it abuts the edge of the cap 17 and, as the pendulum movement continues, must overcome the restoring moment caused by this elastic cap.

Fig. 37 shows a next embodiment, in which the upstanding legs of the L-shaped foot elements 4 rest on their inwardly directed edges against a central wedge 32. This central wedge is axially displaceable along the leg part and enables a precise initial angular position of the rollers on the foot parts 4. A suitable suspension holds the foot elements in position.

A further embodiment with L-shaped foot elements 4 is shown in FIGS. 38a and 38b. In this embodiment, the spring force for the restoring moment of the foot elements 4 is provided by a spring ring 9 ^I , which is essentially designed as a foot ring on the back of the horizontal

Leg 29 is arranged. The diameter of this spring ring 9 ^IV is selected so that it comes to rest essentially on the outer regions of the foot elements 4.

The cross section of the foot ring 9 ^I can be designed in a special way to provide a desired restoring force. In the embodiment according to Fig. 38a has the spring ring 9 ^I in cross section a z. B. approximately egg-shaped shape, which provides a high return torque in relation to the cross section of the ring itself. However, a flat-lying ring can also be used, which has a softer resetting characteristic. A next embodiment is shown in Figs. 39 and 40. In this embodiment variant, the foot part 5 is formed by an elastic hollow body 33, on the outer sides of which the foot elements 4 are fixed essentially rigidly. In this embodiment, the hollow body 33 preferably has a spherical shape. The cavity 34 of the hollow body 33 is pressurized via a valve 35, and the outer wall of the hollow body 33 is elastically deformable, as a result of which a foot element 4 fastened thereon is able to perform a substantially spatial pivoting movement.

Fig. 41 shows a next embodiment of a foot part 5. In this embodiment, the holding arrangement is directly attached to a tubular extension 15 'of the leg part 3. The tube extension 15 'has a retaining washer 36, on the underside of which retaining webs 37 are provided, between which the axle bolt 14 is fastened. In the area of the outer circumference, a disk-shaped spring arrangement 9 is fastened under the holding disk 36, against which the back 4 ′ of a foot element 4 bears. At a distance above the axle pin 14, a stop 38 is provided under the retaining washer 36, by means of which it is ensured that the foot element 4 cannot unhook from the axle pin 14 during dynamic rocking movements.

The spring assembly 9 consists in the illustrated embodiment of a spring ring 9, which has a three-layer structure. These three layers can be any combination of differently hard or soft elastomers, for example the bottom layer can consist of a non-elastomeric material, and, as shown in FIG. 20, a certain geometry of the contact surfaces of at least two can Layers are provided which allow a different spring characteristic to be set by rotating the two layers concerned by a predetermined angle.

In the setting shown in Fig. 42, the elastomer ring 9 ^V , which consists of an elastic material, has the greatest spring strength. If the top layer is rotated by so many degrees that the two layers are opposite each other by half a ramp length; this allows the elastomeric material of one layer, or, if both layers are such an elastomeric material, also of the other layer to partially escape into the free space created, which results in a softer spring constant of the overall ring.

[00146] In a special embodiment, these can be particularly designed contact surfaces, which have a coarse sawtooth pattern in FIG. 42, are additionally equipped with a very fine sawtooth pattern, cf. detail, which prevents a spring washer rotated into a predetermined position from rotating back due to the dynamic movement.

An alternative embodiment to such an elastomer ring 9, as used in the exemplary embodiments according to FIGS. 41 and 42, can consist in that a rubber hose is used, the hardness of which can be regulated by higher or lower air pressure.

Fig. 43 shows a next embodiment of the invention. In this embodiment variant, the holding arrangement 10 is also formed on a sleeve on the tube part 15 ′ of the leg tube 3. The foot elements 4 are arranged on the sleeve so as to be pivotable about the axle pin 14. A pressure plate 39 is arranged on the end face of the foot element 4 on both sides. When the foot element 4 swivels upwards, this pressure plate 39 pivots in the direction of the pipe section 15. At the level of the working area of the pressure plate 39, an elastomer ring is placed around the pipe part 15, so that the pressure plate 39, depending on the extent of the swiveling movement, this ring 9 compresses more or less. The elastic deformation exerts a restoring moment on the pressure plate and thus on the foot element 4.

In the exemplary embodiments shown in FIGS. 43-45, stoppers 40 are arranged on the radially outer ends of the foot elements 4, which are located radially outside the contact surfaces between the base and the roller 8.

While the stopper 40 is rigidly arranged on the foot element 4 in the embodiment shown in FIG. 43, the stopper 40 is an integral part of the embodiment shown in FIGS. 44 and 45

Roller suspension, ie the stopper 40 forms an extension of the axis of rotation 42 about which the roller 8 can be pivoted. This changes the relative position of the stopper 40 to the roller, ie when the roller is pivoted radially outward, the stopper is located between the contact point 43 roller / floor and center of the stool; If the roller is pivoted inwards, the stopper 40 is outside this dimension. The end region of the foot element 4 or the roller holder can be designed so softly or to a certain extent that it is articulated to such an extent that when the pendulum is loaded, the rollers 8 "turn out" and the stoppers 40 can thus come into contact with the ground. This creates a braking effect and the chair cannot roll away. F 915 SP / SP - 38 -

In the embodiment shown in Fig. 46, the stopper 40 is always rigid within the stool center / role distance. As a result, the stopper 40 with its rubber knob 41 can always come into contact with the ground when the pendulum tendency in the direction of the foot element 4 exceeds a certain number of degrees. The reason for this is that when swiveling forward the pivot point of the suspension of the foot element 4 on the holding arrangement 10 approaches the floor, a relative upward pivoting movement of a foot element 4 takes place, but the angle between the foot element 4 and the floor becomes smaller. Also in Fig. 47 illustrated embodiment, the stopper 40 is within the distance between the stool center and the roller, namely in the immediate vicinity of the leg part tube 15. The stopper 40 here has the shape of an apron, the outer edge of which is supported on the floor with a corresponding inclination of the leg part (3) ,

This special stopper arrangement represents a safety device that prevents the stool from rolling under the user in the opposite direction to the pendulum deflection during excessive pendulum movement. In contrast, the stopper arrangement, which lies radially outside of the contact point 43, causes a larger angle between the foot element 4 and the floor, so that due to this inclination, the outside stopper 40 comes into contact with the floor and thus holds the stool in place. This effect also occurs with the foot elements which are opposite to the one in the direction of which the pendulum movement is carried out. These foot elements, which face away, also assume a steeper angle of the floor surface, as a result of which the outside stopper 40 comes into contact with the floor.

It is expressly pointed out that any combinations of the exemplary embodiments shown in the description are possible and, therefore, the scope of protection of the patent is not left when implementation combinations not described are implemented. For example, it is possible for the stopper device to interact with any construction of a spring arrangement, and is therefore not limited to the exemplary embodiment from FIG. 43.

In Fig. 48 an embodiment is shown in which the stopper 40 is pivoted forward by means of an actuating structure 44 during the pendulum and makes contact with the ground. For this purpose, the stopper 40 is pivotally mounted.

[00155] FIG. 49 shows a further embodiment variation of the invention. In this embodiment, the foot element is divided into a movable Chen part 4 'and a rigid part 4 ". The movable part 4' is articulated on the rigid part 4". The second spring arrangement 9 is formed between the two parts. In the exemplary embodiment shown, a hinge 44 is provided on the underside of the foot element 4, which serves as a hinge between the movable part 4 'and the fixed part 4 ". The mutually opposite separating surfaces of the parts 4' and 4" together form one V-shaped cutout in which a compression spring 9 "is inserted. In the event of a pendulum load, the movable part 4 'gives against the resistance of the compression spring 9" and thus experiences a restoring moment.

It goes without saying that this embodiment is not limited to the compression spring 9 ″ arranged in the V cutout. A leaf spring can be provided instead of a compression spring. In such a case, the V cutout enables the unhindered relative rotation of the two parts 4 'and 4 "against each other.

Basically, any other spring construction can be chosen, which - allows to exert a restoring torque between the parts 4 'and 4 "when the movable part 4' performs a relative pivoting movement due to the pendulum movement with respect to the fixed part 4".

$$: £ £

Claims

claims:

1. Pendulum chair with a seat part (2), at least one leg part (3), at least one foot portion (5) having a predetermined plurality of foot elements (4), and with at least one spring arrangement (6), characterized in that at least one of the Base elements (4) and / or a sub-element (4 ') of which is designed to be movable and is subjected to a resilient restoring torque when loaded.

2. Chair (1) with at least one leg part (3) and at least one foot part (5) having a predetermined plurality of foot elements (4), at least one support element (8) being connected to each of the foot elements (4), characterized in that that at least one of the foot elements (4) and / or a partial element thereof is designed such that when the chair (1) is loaded, it executes a spring-soft lowering movement in which at least one support element (8) moves with respect to a standing surface (9) and thereby a support point of the chair (1), which is defined by the position of the at least one support element (8) with respect to a central axis (11) of the chair (1), is shifted to the outside.

3. Chair (1) according to claim 1 or 2, wherein the foot elements (4) are resiliently mounted or suspended.

4. Chair (1) according to claim 1, 2 or 3, wherein the foot elements (4) act resiliently in themselves, the foot elements (4) preferably comprising an elastic material for this purpose.

5. Chair (1) according to one of the preceding claims, wherein the foot elements (4) are arranged essentially in a star shape, characterized in that the foot elements (4) and / or partial elements can be pivoted up and down substantially individually and in that a Spring arrangement (4.11) engages at least one specific foot element (4) or partial element.

6. The chair (1) according to any one of claims 2 to 5, characterized in that the support elements (8) are sliding elements which preferably have a sliding surface in order to have a sliding / sliding movement along the standing surface (9). permit.

7. The chair (1) according to any one of claims 2 to 5, characterized in that the support elements are rollers (8) which at the ends of the foot elements (4) are arranged.

8. Chair (1) according to one of claims 1 to 7, characterized in that in the lower region of the at least one leg part (3) on the foot part (5) at least one holding arrangement (4.10 - 4.12) is formed on the at least one of the foot elements (4) is included.

9. Chair (1) according to claim 8, characterized in that at least one foot element (4) is suspended on the holding arrangement (4.10 - 4.12) and is held in position with at least one counterpart.

10. Chair (1) according to claim 8 in combination with claim 4, characterized in that the at least one spring arrangement is formed on the holding arrangement.

11. Chair (1) according to one of claims 1 to 10, characterized in that the at least one spring arrangement is a piece of elastomer against which a region of the foot element (4) or the partial element rests resiliently.

12. Chair (1) according to any one of claims 1 to 10, characterized in that the at least one spring arrangement has at least one tension / compression spring which is formed on the leg part (3) or on the holding arrangement (4.10 - 4.12) and between at least a foot element (4) and the leg part (3) or the holding arrangement (4.10 - 4.12) acts.

13. Chair (1) according to any one of claims 1 to 12, characterized in that for the at least one spring arrangement with a setting means for switching ^~ stelleτrdes spring force formed str ^~

14. Chair (1) according to one of claims 1 to 13, characterized in that an abutment is formed on one end of the foot element (4) on which at least one spring element of the spring arrangement acts.

15. The chair (1) according to any one of claims 1 to 13, characterized in that at least one of the foot elements (4) has at least one slot that is essentially open at the bottom on one end.

16. Chair (1) according to any one of claims 1 to 15, characterized in that the foot element (4) can be pivoted downwards and can be mounted at least in the position pivoted downwards by simple attachment.

17. Chair (1) according to any one of the preceding claims, characterized by means which prevent an uncontrolled translational movement of the pendulum chair.

18. The chair (1) according to claim 9 in combination with claim 5, characterized in that the at least one spring arrangement is formed on the counterpart.

19. The chair (1) according to claim 1, characterized in that the support elements are unbraked rollers (8) which are connected to the foot elements (4), each of the rollers (8) about a wheel axis (8.1 ) of a suspension (6) is mounted on a roll and is connected to the foot element (4) so that it can rotate freely via a guide axis (6.5) in such a way that during the lowering movement at least one of the rollers (8) automatically performs an immersion movement in which the guide axis (6.5) the at least one roller (8) changes its inclination (β) with respect to the standing surface (9) and the seating point of the chair (1) is thereby shifted outwards.

20. The chair (1) according to claim 19, characterized in that when the chair (1) is loaded, the rollers (8) automatically assume a position due to the lowering and immersion movement, in which at least two of the rollers (8) have different positions Show directions and thereby brake the entire chair (1) in relation to ^" the standing surface (9).

21. The chair (1) according to any one of claims 1 to 3, characterized in that the foot part (4) comprises at least three foot elements (4) and the leg part (3) has a central column which is substantially parallel to the central axis (11), each of the foot elements (4) being suspended mechanically with respect to the column (3) in such a way that the foot elements (4) perform a pivoting movement during the lowering movement and move radially apart, the foot elements (4) having a Restoring force are applied.

22. The chair (1) according to claim 19, characterized in that the suspensions (6) are so rigidly connected to the foot elements (4) that the suspensions (6) can rotate about the guide axes (6.5) their inclination (ß) with respect to the foot elements (4) does not change.

23. The chair (1) according to claim 19, characterized in that the suspension (6) is connected to the foot part (5) in such a way that it can rotate about the guide axis (6.5) and the inclination (β) of the guide axis (6.5) in relation changes on the foot part (5) during the lowering movement of the chair (1).

24. The chair (1) according to one of claims 1 to 4, characterized in that the foot part (5) comprises a foot element (4) which is deformable.

25. The chair (1) according to claim 19, characterized in that the immersion movement is a movement which results from a rolling and swiveling movement of at least one of the rollers (8).

26. The chair (1) according to any one of the preceding claims, characterized in that reset means (3.6, 4.1, 4.7, 4.8, 4.9, 4.10, 4.11, 4.12, 4.13, 4.14, 12, 14; 15) are provided to a Apply resetting force.

27. The chair (1) according to any one of claims 19 to 26, characterized in that the rollers (8) are per se unrestrained in any position.

28. The chair (1) according to any one of claims 19 to 27, characterized in that when the chair (1) is weight-centered, all the rollers (8) automatically follow one another in a coordinated manner when the chair (1) as a whole with respect to the standing area (9) is moved.

29. Chair (1) according to any one of claims 19 to 28, characterized in that the suspension (6) of the rollers (8) is designed so that there is an eccentric bearing of the rollers (8), in which the guide axis (6.5 ) is aligned so that it does not intersect the wheel axis (8.1).

30. Chair (1) according to any one of claims 19 to 29, characterized in that the wheel axis (8.1) and the guide axis (6.5) in a plane which is perpendicular to the wheel axis (8.1) have a distance (A) which is at least 0.5 cm and preferably between 1 cm and 3 cm.

31. Chair (1) according to one of claims 1 to 30, characterized in that the chair (1) has an enlarged footprint due to the lowering movement under load.

32. Chair (1) according to any one of claims 2 to 31, characterized in that the rollers (8) including the suspension (6) change from an unstable to a stable position when the chair (1) is loaded.

33. The chair (1) according to any one of claims 1 to 32, characterized in that it allows an active rocking / tilting movement.

34. The chair (1) according to any one of claims 2 to 33, characterized in that the foot part (3, 4) and / or the support elements (8) are arranged mechanically in such a way that the support elements (8) automatically close in the unloaded state the foot part (3, 4) are pulled together and as a result of this contraction, the support points of the chair (1) are shifted closer to the central axis (11).

35. Chair (1) according to any one of claims 2 to 34, characterized in that in the unloaded state, at least two of the rollers (8) automatically align radially, point inwards and the entire chair (8) thereby in relation to the standing area (9) brake.

36. Chair (1) according to one of claims 7 to 35, characterized in that the rollers (8) have a cross-section comprising the wheel axis (8.1), which is essentially U-shaped or O-shaped.

37. Chair (1) according to claim 7, characterized in that each of the foot elements (4) is suspended from a central column (3) in such a way that the foot element (4) can rotate about its longitudinal axis and thereby the guide axis ( 6.5) is also rotated, as a result of which the position of the rollers (8) changes and a braking effect occurs.

38. Pendulum chair according to claim 17, characterized in that the means have a stopper (40) which comes into contact with the floor at a predetermined inclination of the leg part (3) and due to the friction with the floor a translational movement of the pendulum chair (1 ) prevented.

39. Pendulum chair according to claim 38, characterized in that the stopper (40) is coupled to the roller (8) or the leg part (3) via an actuation / articulation (42; 44) and at a predetermined inclination of the leg part (3) is pressed to the ground.

40. Pendulum chair according to claim 38 or 29, characterized in that the stopper (40) is rigidly arranged at the outer end of the foot and is located radially outside of the circumference in relation to a circumference on which all the rollers (8) are arranged.