EP1659902B1 - Chair comprising mobile, elastic legs, permitting a dynamic sitting position - Google Patents

Description

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

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

From the US-A-1930021 is known a chair whose foot consists of star-shaped leaf springs. The leaf springs are essentially S-shaped and have rollers at their lower end. At its upper end, they are suitably fixed to a receiving part which carries a column on which the seat is tiltably held. When the chair is loaded, the star-shaped arms spring outward and create a resilient restoring moment.

From the Japanese patent JP11318627A For example, a chair is known which has a central pillar with a base on the floor and three feet spaced around this central pillar and designed to be spring-loaded. This design allows the user to perform a pendulum motion.

A pendulum stool, which is suitable for dynamic sitting, is the European patent application EP 0 808 116 refer to. In 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 the WO 01/91615 A1 is a chair known, which is equipped with feather-soft chair feet and a weight-centered seat mechanism. In the document, a five-star foot is disclosed, which is equipped at its free ends with rollers which are resiliently mounted on a rubber ring. As a further suspension with soft feet, instead of a five-star, a circular disc made of spring steel is described, which allows a lateral pivoting or tumbling motion.

The present invention has for its object to propose a pendulum chair or a chair that allows dynamic sitting and is preferably easy to move.

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

Finally, the object of the present invention is to design rolling or sliding chairs with simple means in such a way that significantly more movements of the user are possible without impairing safety and thus avoiding postural injuries that arise when sitting rigidly.

Furthermore, the aim is to provide a chair that allows safe and comfortable to sit on a higher level. Above all, it should be avoided that such a chair can suddenly tip over in exposed positions.

The objects are achieved by the teachings disclosed in the independent claims 1 and 2.

According to the invention, a chair is provided with a preferred embodiment, which has a plurality of support elements in the region of the foot elements, which are arranged on a resiliently acting foot part of the chair. When the chair is loaded, a lowering movement of the chair results and at least one of the support elements displaces in relation to a standing surface.

To achieve this, foot elements of the chair can either be resiliently mounted or they can be designed resiliently from the material and / or structure. It is also possible a combination of a resilient mounting with resiliently executed foot elements.

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

A chair according to the invention makes it possible to move up and down while sitting, thanks to the use of a springy-action foot part, which enables dynamic relief of the spine. In addition, a chair according to the invention has a supporting effect when getting up and sitting down. As a result, when sitting down, for example, beats on the spine are damped. The up and down is achieved without a special vertically arranged spring element, for example in the form of a coil spring, is required in the foot part of the chair, solely by the resilient mounting, or the elasticity of the foot elements

Since new ergonomic findings make significantly higher demands on the variability and flexibility of chairs, the present invention provides solutions for dynamic sitting on chairs. In particular, the present invention is suitable for use in chairs having support elements (rollers, sliders or the like).

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

It is a further advantage of the invention that the corresponding chairs are flexible, mobile and yet safe.

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

Conveniently, an embodiment with star-shaped foot elements in which the foot elements and / or a sub-element thereof is spring-loaded up and down pivotally, whereby it is possible to specify the respective loaded by the pendulum movement direction by corresponding spring strengths.

An embodiment in which at least one receiving portion is formed in the lower region of at least one leg part, on which at least one of the foot elements is received, is favorable. This receiving part may conveniently be designed so that a foot element can be suspended thereon, wherein a counterpart of this foot element holds in position.

It is advantageous embodiment in which at least one spring arrangement is formed on a counterpart, which may alternatively be formed on the receptacle. In this case, the spring arrangement can favorably consist of a piece of elastomer, against which a region of the foot element or of the partial element rests resiliently.

As a further embodiment, a spring arrangement may be provided which comprises a pull or a compression spring which is arranged on a leg part or on a receiving part and acts between at least one foot element and the leg part or the receiving part.

To adjust the spring force advantageously an adjustment is provided on the spring assembly.

It may be favorable that an abutment is arranged on the leg end of the foot element, on which acts at least one spring element of the spring arrangement. According to the invention, a leg-side end of at least one of the foot elements is formed as at least one substantially downwardly open slot.
This advantageously achieves that one can simply hang the foot element, and it can be conveniently provided that the foot member is pivotable downwards and at least in the downwardly pivoted position by simple placement can be mounted.
It may be beneficial to provide means to prevent uncontrolled translational movement of the chair during a pendulum motion.

Particularly advantageous is an embodiment in which the foot part comprises foot elements which are suspended so mechanically with respect to the foot part, that they are acted upon by a spring element with a restoring force. This restoring force counteracts a Spreizschwenkbewegung that results when the load on the chair and tries the radially moving foot elements to a central axis of the chair to draw zoom. Preferably, you can make the restoring force adjustable or specifiable.

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

It may be convenient to provide means that prevent uncontrolled translational movement of the pendulum stool during the pendulum motion.

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

This stopper may be coupled via a hinge connection with the leg part, but it may also be rigidly fixed to the leg part and come in contact with the ground at a predetermined inclination of the leg part.

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

Fig. 1A-1C

schematische Schnittansichten eines Teils eines konventionellen Bürostuhls;

Fig. 2A-2B

schematische Schnittansichten einer Variante eines Bürostuhls;

Fig. 3

eine schematische Schnittansicht des Fusses eines Stuhls in einer extremen Lage;

Fig. 4A-4B

schematische Seitenansichten eines Teils eines ersten Bürostuhls;

Fig. 4C-4D

schematische Draufsichten des ersten Bürostuhls bei zentrischer Belastung;

Fig. 5A-5B

schematische Seitenansichten eines Teils eines zweiten Bürostuhls;

Fig. 6A-6B

schematische Seitenansichten eines Teils eines dritten Bürostuhls;

Fig. 7A-7B

schematische Seitenansichten eines Teils eines vierten Bürostuhls;

Fig. 8A-8B

schematische Seitenansichten eines Teils eines fünften Bürostuhls, gemäss Erfindung;

Fig. 9

eine perspektivische Ansicht eines sechsten Bürostuhls;

Fig. 10A-10B

schematische Seiten- und Schnittansichten eines Teils eines siebten Bürostuhls;

Fig. 11A

eine perspektivische Ansicht eines Teils eines achten Bürostuhls;

Fig. 118-11E

schematische Seiten-, Drauf- und Schnittansichten des achten Bürostuhls;

Fig. 12A-12B

schematische Seiten- und Schnittansichten eines neunten Bürostuhls, gemäss Erfindung;

Fig. 13

eine schematische Seitenansicht eines zehnten Bürostuhls;

Fig. 14

eine schematische Schnittansicht eines elften Bürostuhls;

Fig. 15

eine schematische Seitenansicht eines Teils eines zwölften Bürostuhls;

Fig. 16

eine perspektivische Ansicht auf ein Fussteil von schräg oben einer weiteren Ausführungsform gemäss Erfindung;

Fig. 17

eine schematische Darstellung einer nächsten Ausführungsform eines Bürostuhls;

Fig. 18

eine schematische Darstellung einer nächsten Ausführungsform eines Bürostuhls;

Fig. 19

eine schematische Darstellung einer nächsten Ausführungsform eines Bürostuhls, gemäss Erfindung;

Fig. 20

eine Darstellung eines alternativen Details der Ausführungsform gemäss Fig. 19;

Fig. 21

eine schematische Darstellung einer nächsten Ausführungsform eines Bürostuhls;

Fig. 22

eine schematische Darstellung einer nächsten Ausführungsform eines Bürostuhls;

Fig. 23

eine schematische Darstellung eines Axialschnitts durch einen erfindungsgemäßen Pendelhocker,

Fig. 24

eine perspektivische Ansicht einer Darstellung von schräg unten auf das Fußteil des Pendelhockers,

Fig. 25

eine alternative Ausführungsform des Fußteils mit einer ersten Ausführungsvariante der Federanordnung,

Fig. 26

eine nächste Ausführungsform des Fußteils mit einer Ausführungsvariante der Federanordnung, bei die Fußelemente gegen elastomeres Material anliegen,

Fig. 27

eine perspektivische Ansicht der Halteanordnung mit Elastomerfeder gesehen von schräg unten,

Fig. 28

ein Ansicht eines Axialschnitts durch das Beinrohr und die Halteanordnung,

Fig. 29

eine perpektivische Ansicht auf ein Fußteil von schräg oben mit einer weiteren Ausführungsform der Rückstellfeder,

Fig. 30

eine Schnittansicht auf ein Detail der Ausführungsform gemäß Fig. 7,

Fig. 31

eine Ansicht auf den Schnitt A - A in Fig. 8,

Fig. 32

eine schematische Darstellung einer Federanordnung,

Fig. 33

eine schematische Darstellung einer weiteren Ausführungsform der Federanordnung,

Fig. 34

eine schematische Darstellung einer Federanordnung,

Fig. 35a

eine Darstellung eines alternativen Details des Beispiels gemäß Fig. 11,

Fig. 36

eine schematische Darstellung einer Fußteil- und Federanordnung,

Fig. 37

eine schematische Darstellung einer Federanordnung,

Fig. 38

eine schematische Darstellung einer Federanordnung,

Fig. 39

eine schematische Darstellung einer Federanordnung,

Fig. 40a

eine schematische Darstellung einer Federanordnung,

Fig. 41b

eine perspektivische Ansicht der Ausführungsform nach Fig.16a,

Fig. 42

eine schematische Darstellung im Schnitt einer weiteren Ausführungsform der Federanordnung,

Fig. 43

eine perspektivische Ansicht des Beispiels nach Fig. 17,

Fig. 44

eine schematische Darstellung im Schnitt einer Federanordnung mit Federscheibe,

Fig. 45

eine perspektivische Ansicht einer Federscheibe gemäß Fig. 19,

Fig. 46

eine schematische Darstellung einer Federanordnung mit Stopper,

Fig. 47

eine schematische Darstellung einer Federanordnung mit Stopper,

Fig. 48

eine schematische Darstellung des Beispiels nach Fig. 22 mit dem Stopper in Funktionsstellung,

Fig. 49

eine schematische Darstellung einer Federanordnung mit Stopper,

Further details and advantages of the invention will be described below with reference to embodiments and with reference to the drawings. Drawings 1-11, 13-15, 17, 18, 21-22, 31, 32, 34-40, 43-49 show a basis for the clear understanding of those in the drawings 12, 16, 19, 20, 23-30, 33, 41, 42 chairs shown and form no part of the present invention. Show it:

Fig. 1A-1C

schematic sectional views of a part of a conventional office chair;

Fig. 2A-2B

schematic sectional views of a variant of an office chair;

Fig. 3

a schematic sectional view of the foot of a chair in an extreme situation;

Fig. 4A-4B

schematic side views of a portion of a first office chair;

Fig. 4C-4D

schematic plan views of the first office chair with centric load;

Fig. 5A-5B

schematic side views of a portion of a second office chair;

Figs. 6A-6B

schematic side views of a portion of a third office chair;

Figs. 7A-7B

schematic side views of a portion of a fourth office chair;

Figs. 8A-8B

schematic side views of a portion of a fifth office chair, according to the invention;

Fig. 9

a perspective view of a sixth office chair;

10A-10B

schematic side and sectional views of a portion of a seventh office chair;

Fig. 11A

a perspective view of part of an eighth office chair;

Fig. 118-11E

schematic side, top and sectional views of the eighth office chair;

Figs. 12A-12B

schematic side and sectional views of a ninth office chair, according to the invention;

Fig. 13

a schematic side view of a tenth office chair;

Fig. 14

a schematic sectional view of an eleventh office chair;

Fig. 15

a schematic side view of part of a twelfth office chair;

Fig. 16

a perspective view of a foot part obliquely from above another embodiment according to the invention;

Fig. 17

a schematic representation of a next embodiment of an office chair;

Fig. 18

a schematic representation of a next embodiment of an office chair;

Fig. 19

a schematic representation of a next embodiment of an office chair, according to the invention;

Fig. 20

a representation of an alternative detail of the embodiment according to Fig. 19 ;

Fig. 21

a schematic representation of a next embodiment of an office chair;

Fig. 22

a schematic representation of a next embodiment of an office chair;

Fig. 23

a schematic representation of an axial section through a pendulum stool according to the invention,

Fig. 24

a perspective view of a representation obliquely from below on the foot of the pendulum stool,

Fig. 25

an alternative embodiment of the foot part with a first embodiment of the spring arrangement,

Fig. 26

a next embodiment of the foot part with an embodiment variant of the spring arrangement, wherein the foot elements abut against elastomeric material,

Fig. 27

a perspective view of the holding arrangement with elastomer spring seen obliquely from below,

Fig. 28

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

Fig. 29

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

Fig. 30

a sectional view of a detail of the embodiment according to Fig. 7 .

Fig. 31

a view of the section A - A in Fig. 8 .

Fig. 32

a schematic representation of a spring arrangement,

Fig. 33

a schematic representation of another embodiment of the spring arrangement,

Fig. 34

a schematic representation of a spring arrangement,

Fig. 35a

a representation of an alternative detail of the example according to Fig. 11 .

Fig. 36

a schematic representation of a Fußteil- and spring assembly,

Fig. 37

a schematic representation of a spring arrangement,

Fig. 38

a schematic representation of a spring arrangement,

Fig. 39

a schematic representation of a spring arrangement,

Fig. 40a

a schematic representation of a spring arrangement,

Fig. 41b

a perspective view of the embodiment according to Figures 16A .

Fig. 42

a schematic representation in section of another embodiment of the spring arrangement,

Fig. 43

a perspective view of the example Fig. 17 .

Fig. 44

a schematic representation in section of a spring arrangement with spring washer,

Fig. 45

a perspective view of a spring washer according to Fig. 19 .

Fig. 46

a schematic representation of a spring arrangement with stoppers,

Fig. 47

a schematic representation of a spring arrangement with stoppers,

Fig. 48

a schematic representation of the example according to Fig. 22 with the stopper in functional position,

Fig. 49

a schematic representation of a spring arrangement with stoppers,

Detailed description:

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

In the following, advantageous embodiments of the invention are described, which are exemplary embodiments. These include both various embodiments of the overall invention, as well as assemblies and components 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 in this case can cause smaller, familiar to any person skilled and therefore not further described adjustments, for example, to allow interaction or interlocking of the modules and items.

In the following, several so-called feather soft, elastic foot elements the speech, It is according to the invention to feather soft elastically mounted foot elements with a return element and / or foot elements that act resilient and resilient by their own elasticity. The elasticity of the foot elements can be achieved by suitable choice of material, the combination of different materials and / or by the shaping.

The following is several times of so-called support elements talk. In the present context, these are elements which can be fastened to a foot part of a chair and which can simply be moved or moved along a standing surface. Particularly suitable as support elements are sliding feet, or other sliding elements, and rollers, as sliding elements are preferably elements are used, the sliding surface are adapted to the nature of the base. For example, if the chair is to be used on a carpet, the sliding surface is provided with a corresponding layer which allows it to slide on the carpet. Particularly suitable is a Teflon or nylon coating. In a smooth floor space (parquet, stone floor, or the like) preferably another sliding surface is used, for example plastic or felt.

In the following, instead of supporting elements various specifically talked about roles. The term roll is to be understood in this context as a wheel or a roller which can rotate about a wheel axle. Particularly advantageous are rollers that are rounded. Twin roles are referred to as roles.

Before describing various embodiments of the invention, first of all the various movements which may result in conventional chairs will be discussed. Thus, the basis is laid for understanding the complex dynamic relationships which are used in a targeted manner for a part of the chairs according to the invention, whereby according to the invention, as will be described, different effects and movements are superimposed in a complex manner and only with appropriate dimensioning, respectively configuration ever occur. The various effects and movements interact positively, as explained in connection with the various embodiments.

In the FIGS. 1A to 1C is the behavior of a conventional office chair shown. The section of a foot element 4 of a star-shaped foot cross (foot part) is shown. At the free end of the foot member 4, a suspension 6 is arranged, which carries a roller 8. In the simple example shown, the 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 sits in turn in a receptacle 6.4, which is provided in the foot element 4. Typically, a sleeve is 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 is perpendicular to a base 9 in the example shown. Between the guide shaft 6.5 and the wheel axle 8.1 there is a small offset, which is referred to here as eccentric bearing.

If the chair is now pulled in the positive X direction, then the roller 8 follows the foot element 4, as in FIG Fig. 1A shown. The roller rotates clockwise, as shown by the arrow 8.2. If the chair is moved in the opposite direction, ie parallel to the negative X-axis, then the in Fig. 1B shown state in which the roller 8 precedes the foot element 4. The roller rotates counterclockwise, as shown by the arrow 8.2. This condition is unstable. The roller 8 has the tendency immediately reverse as soon as a small "disturbing" force acts laterally on the roll. The role jumps from the pushed state ( Fig. 1B ) into a position around in Fig. 1C is indicated. 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 train carriage.

Another conceivable variant of a chair is in the FIGS. 2A and 2B shown. The variant of the chair shown differs essentially thereby from the chair of FIGS. 1A to 1C in that the guide shaft 6.5 is inclined. If the chair is now pulled in the positive X direction, then the roller 8 follows the foot element 4, as in FIG Fig. 2A shown. The roller rotates clockwise, as shown by the arrow 8.2. This position is relatively stable, since the virtual starting point A1 is closer to the base 9 than in the arrangement in the FIGS. 1A to 1C , If the chair is now moved in the opposite direction, ie parallel to the negative X-axis, then the results in Fig. 2B shown state where the roller 8 runs behind the foot element 4. In order to assume this state, however, a resistance to gravity must be overcome, since the distance A between the foot element 4 and base 9 must increase during the transition to this state. Order from the in Fig. 2A shown location in the Fig. 2B To reach the position shown, the roller 8 must make a 180 degree rotation about the guide axis 6.5. The virtual starting point A1 shifts upwards. This effect is in Fig. 1B exaggerated. If the inclination of the guide axis 6.5 with respect to the vertical position is low, then a small disturbance (for example a unevenness of the standing surface 9 or an unbalanced load) is sufficient to cause it to snap into the in Fig. 2A to trigger shown position. An increasing inclination of the guide shaft 6.5 with respect to the vertical position leads to a continuous deterioration of the all-round rotation capability (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 shaft 6.5 and the wheel axle 8.1, there are two eccentric effects that can be more or less pronounced. The first eccentric effect, as described, is shown as an increase in the distance A. The second eccentric effect occurs because the rollers "tip over" over their edge when they jump around. This second eccentric effect occurs all the more, the more edged the rollers are executed. For twin rolls, this effect is less pronounced.

As in Fig. 3 shown highly schematically, the roller 8 in the extreme case shown (the guide shaft 6.5 is parallel to the ground 9 and cuts the wheel axis 8.1) no longer fast-moving. The flatter the guide axis 6.5 is, the more one approaches this extreme case.

Another extreme case is that in which the guide axis 6.5 is arranged vertically above the wheel axle 8.1 and the two axes intersect. The direction change is only possible continuously because the rollers do not adjust in the direction of travel. This case is not shown graphically.

The previously related to the FIGS. 1A to 1C and 2A, 2B described chairs have arrangements of the rollers, in which the inclination of the guide axes is rigid with respect to the footprint.

In order to provide a chair that reacts situationally, according to the invention, the foot part of the chair is designed so that it acts resilient under load. This effect can be achieved either by resilient, elastic mounting of the foot elements, or by the fact that the Fusselememente themselves act resilient. It is also possible to combine both effects

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

There are support elements provided on the foot part, which can move relative to the base surface when the foot elements move and / or deform. For this purpose, such a chair may, for example, have glides or castors 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 rollers serve as support elements, wherein this focus is not intended to be restrictive to roller-based embodiments.

1. (1) im unbelasteten Zustand stehen die Führungsachsen der einzelnen Rollen des Stuhles steil, vorzugsweise nahezu senkrecht zur Standfläche oder leicht negativ geneigt, um eine Anfangsblockierung zu bewirken;
2. (2) im belasteten Zustand stehen die Führungsachsen der einzelnen Rollen des Stuhles flach (im Sinne von positiv geneigt), d.h. der Neigungswinkel ist grösser als im unbelasteten Zustand.

In order to provide a chair that reacts situationally, in preferred embodiments of the invention, the position (inclination) of the guide axes of the rollers is made variable. 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 flexible, elastic bearing of the guide pins of the rollers in the foot element. The chair is designed to occupy or seek the following conditions:

1. (1) in the unloaded state, the guide axes of the individual roles of the chair are steep, preferably almost perpendicular to the base or slightly inclined negative to cause a beginning blocking;
2. (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 inclination angle is greater than in the unloaded state.

By this situation-dependent tilting of the guide axes, the degrees of freedom of the roller system are reduced, which has the consequence that a coordinated running 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 a braking effect results from the interplay of at least two rollers. This braking effect is created without the need for a braking medium that brakes the rollers individually. By this braking effect slows down the chair as a whole and can no longer be moved with respect to the footprint.

However, the individual rollers 8 of the chair 1 are still movable - speak unbraked - and can roll radially to a central axis 11 of the chair 1, to allow a (resilient) up and down of the chair 1, as in the FIGS. 4A to 4D indicated schematically. A dynamic sitting is thus still possible according to the invention, even if the braking effect, as described, occurs.

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

According to the invention, the guide axle and the wheel axle of a roller suspension are related to one another in such a way that, when the chair is loaded, the roller changes from a so-called unstable position to a so-called stable position. This transition is referred to herein as a dip. This immersion movement is clearly noticeable on the chair, depending on the embodiment, and includes a rolling and pivoting movement of the rollers (double eccentric action). A roller performs a small rolling motion around the wheel axle during the dipping movement and the roller pivots about 180 degrees about the guide axle. When pivoting about the guide axis, the roller tilts over one of its edges which define the transition of the tread into the side wall of the roller. These effects have already been linked with Fig. 2B described.

The aforementioned effects that occur when the rollers move from one position to another, more stable position are influenced by various parameters, but essentially either support or mitigate the effects. An example is the shape of the roles. If cylindrical rolls or twin rolls are used whose cylinder axis corresponds to the wheel axis, it is more difficult to reverse the rolls depending on the dimensions. On the other hand, thinner rollers or spherical rollers are easier to pivot around the guide axis because their running surface has a smaller extent parallel to the wheel axis. Another parameter is the eccentricity (initially referred to as offset), i. the distance of the guide axis 6.5 with respect to the wheel axle 8.1. Another possibility to influence the mentioned effects results from the storage of the rolls. Smooth-running rollers follow the movements of the chair faster and you can give the chair agility in its behavior. By a slightly braked storage of roles, the behavior can be damped. The chair behaves less aggressively.

Analogously, sliding elements with good slipperiness are faster and easier to follow the movements of the chair. Less well sliding glides lead to a chair that behaves less aggressively.

It follows - 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 base, etc.) - a distorting effect of the described movement behavior ,

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

This outward displacement counteracts a restoring force, which can come about in various ways. In the case of rigid foot elements 4 (legs) which are movably fastened to a central pillar 3 of the chair 1, a restoring force can be generated by the attachment of spring elements. It can train, leaf, torsion or compression springs are used to apply the restoring force. But it is also conceivable that the foot elements 4 are mounted elastically. An elastic bearing 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 sub-elements thereof, are designed to be resilient. Thus, a foot element due to its shape and / or the materials used to show a resilient effect. Typically, the foot elements 4, or sub-elements thereof deform when the chair 1 is loaded. With increasing deformation, a force sets in (restoring force), which counteracts the deformation.

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

Details of a first embodiment will be described in connection with FIGS FIGS. 4A to 4D described. In Fig. 4C 1 is a schematic top view of a chair 1 having only four rollers 8 arranged in a star shape with respect to a vertical axis 11 of the chair 1. The chair 1 is in Fig. 4C shown in an unloaded condition. The chair 1 defines by the support points of the rollers 8 with the base 9 a bearing surface, which is indicated by a circle with the diameter A1.

The FIGS. 4A and 4B show a sectional view that intersects two of the four rollers 8 that 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 at centric load in the vertical axis 11. The guide shafts 6.5 are in the in Figs. 4A and 4C State shown relatively steep. The inclination angle β is typically in this state between 0 and 30 degrees and preferably between 0 and 10 degrees. Depending on the embodiment, however, it is also conceivable that the guide axis 6.5 have a negative angle β in the unloaded state. At vertical pressure in the direction of the axis 11 from top to bottom changes through the elastically acting foot elements of the negative angle β via a zero position in a positive angle β. As a result of the elastically acting legs, the guide axes 6.5 move away from the vertical axis 11 with increasing vertical pressure on the standing surface 9. The negative angle β can lie between -5 degrees and 0 degrees. If the angle β set negative in the unloaded state, then there is a braking effect (called initial blocking) of the chair 1. In addition, the support surface is reduced by the negative employment of the rollers 8, since all Rolls 8 are star-shaped inward. 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 centrically, as indicated by the arrow 10 in FIG Fig. 4B indicated, so move the rollers 8 radially outwards, as in Fig. 4D can recognize by the enlarged circle. Such a lowering movement of the chair 1 combined with a spreading movement of the foot part of the chair 1 is easily possible because the four rollers 8 can run independently on radially directed tracks to the outside. As a result, an increase in the contact surface takes place (A2 is greater than A1), which has an increased stability of the chair 1 result. The increase in the contact surface is an important characteristic of the chairs according to the invention. It should be noted that an asymmetrical loading of the chair 1 results in an oval or different shape of the support surface A2.

By the described spreading load shocks can be absorbed by a rolling apart of the rollers 8 and it is possible to move up and down. Such a spreading occurs when using sliding analogously.

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

1. (1) Die Aufhängung der Rollen 8 an den Fusselementen 4 erfolgt so, dass sich die Führungsachse 6.5 jeder einzelnen Rolle 8 in Bezug auf das Fusselement 4 je nach Belastung neigen kann (siehe Fig. 5A und 5B);
2. (2) Die Aufhängung der Rollen 8 an den Fusselementen 4 ist starr, aber die Fusselemente 4 sind beweglich am Stuhl 1 befestigt und zwar so, dass sich durch eine Bewegung eines Fusselements 4 die Neigung der Führungsachse 6.5 in Bezug auf die Standfläche 9 ändert (siehe Fig. 6A und 6B);
3. (3) Die Aufhängung der Rollen 8 an den Fusselementen 4 ist starr, aber die Fusselemente 4 sind flexibel und zwar so, dass sich durch eine Verformung des Fusselemente 4 die Neigung der Führungsachsen 6.5 in Bezug auf die Standfläche 9 ändert (siehe Fig. 7A und 7B);
4. (4) Eine Kombination einer oder mehrere der obigen Ansätze.

There are according to the invention, the following approaches to achieve a situation-dependent inclination of the leadership axis (s) of the roles;

1. (1) The suspension of the rollers 8 on the foot elements 4 takes place so that the guide axis 6.5 of each individual roller 8 can tilt with respect to the foot element 4 depending on the load (see Figs. 5A and 5B );
2. (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 the inclination of the guide shaft 6.5 changes with respect to the base 9 by movement of a foot element 4 ( please refer FIGS. 6A and 6B );
3. (3) The suspension of the rollers 8 on the foot elements 4 is rigid, but the foot elements 4 are flexible in such a way that by a deformation of the foot elements 4, the inclination of the guide axes 6.5 with respect to the base 9 changes (see Figs. 7A and 7B );
4. (4) A combination of one or more of the above approaches.

Details of a second embodiment will be described in connection with FIGS FIGS. 5A and 5B described. Shown is a schematic side view of a chair 1. The chair 1 is constructed essentially mirror-symmetrical. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat surface (not shown) and a central pillar 3, which is rigidly connected to the foot elements 4. For example, a rigid base with three, four or five foot elements 4 may be provided. But it can also be a disc, ring or cup-shaped foot element are used in the middle of the column 3 is attached. The column 3 may have at the lower end a cone which sits, for example, in a central hole of such a base or foot element. The roller 8 is from a suspension carried, which includes a fork 6.1. At the upper end of the fork 6.1, a guide pin 6.2 is arranged, which is mounted tiltably in the base element 4. If the chair 1 is loaded, then this lowers and the rollers 8 perform a dip, as in Fig. 5B shown, in which the guide axis 6.5 inclines by an inclination angle β. Depending on the load, the guide shafts 6.5 vary widely when the chair 1 lowers. The bearing surface increases. By tilting the guide shafts 6.5 results in a resilient behavior of the foot part of the chair. 1

Details of a third embodiment will be described in connection with FIGS Figures 6A and 6B described. Shown is a schematic side view of a chair 1, the chair 1 is constructed essentially mirror-symmetrical. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat surface 2 and a central pillar 3. The seat height can be adjusted, for example, as in conventional chairs by the height that a lifting spindle 13 is 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 changes the inclination of the guide axis 6.5 with respect to the base 9 by a movement of a foot member 4. In the embodiment shown, the foot element 4 is connected at its upper end via a horizontal axis 3.4 pivotally connected to the column 3. 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. Preferably, the angle of inclination β at rest is between -5 and 10 degrees. If the chair 1 is centrally loaded, as in Fig. 6B shown, the rollers 8 move radially outward. The foot member 4 is deflected, the inclination angle β is larger. As a result, the Fuhrungsachse 6.5 tilts the roles, as in Fig. 6B can be seen. The inclination angle 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, it is preferable to use a restoring element or to select an arrangement which counteracts a restoring moment of the spreading movement. A greatly simplified return element 12 is in Fig. 6B indicated. It acts on the foot member 4 with a restoring force R, which is directed radially to the axis 11 out. By means of the return element 12, one can influence the characteristic of the pivoting movement and it can be prevented that the foot elements 4 are completely spread and the lower end of the column 3 of the chair 1 touches the base 9. The movement behavior of the foot elements 4, which is determined by the type of suspension and the provision of return elements is referred to as resilient.

According to Fig. 6A, 6B the foot part of the chair 1 has at least three foot elements 4 and a central pillar 3, each of the foot elements 4 being suspended mechanically with respect to the pillar 3 such that the foot elements 4 are under load on the chair 1, as in connection with FIGS Figures 6A and 6B described, perform a pivoting movement and move apart radially. Preferably, the foot elements 4 are acted upon by a restoring force R.

Preferably, in such an embodiment, 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 in the Fig. 6A, 6B shown, can be modified by the guide shaft 6.5 is tiltably mounted, resulting in load of the chair 1 to a superposition of two tilting movements. This also changes the elastic effect.

Details of a fourth embodiment will be described in connection with FIGS FIGS. 7A and 7B described. Shown is a schematic side view of a chair 1. The chair 1 is constructed essentially mirror-symmetrical. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat surface (not shown) and a central pillar 3. Foot elements 4 are provided which are rigidly connected to the pillar 3. The suspension of the rollers 8 on the foot elements 4 is rigid. If the chair 1 is centrally loaded, as in Fig. 7B shown, the rollers 8 move radially outward, since the foot elements 4 are subject to deformation. Depending on the stiffness of the foot elements 4, this deformation may be more or less pronounced. Instead of providing a plurality of individual foot elements 4, a disc-shaped, ring-shaped or cup-shaped foot element 4 can also be used, this element 4 being made elastic. The spring-elastic effect results in this embodiment essentially from the elastic deformability of the foot elements 4.

In Fig. 7A the inclination angle β was about 0 degrees. Under load, the angle of inclination β increases, as in Fig. 7B indicated. With elastically deformable foot elements 4, changes in the inclination angle β between -5 and 30 degrees can be generated. Preferably, the inclination angle is between -5 and 10 degrees.

In the Figures 8A and 8B a further embodiment is shown. Shown is a schematic side view of a chair 1. The chair 1 is constructed essentially mirror-symmetrical. For the sake of simplicity, only part of the chair 1 is shown. The chair 1 comprises a seat surface (not shown) and a central pillar 3. There is provided a disc-shaped elastic foot member 4 which is rigidly connected to the pillar 3. The column 3 is in the example shown with its lower end, which is preferably made 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, then the rollers 8 move radially outward, since the foot element 4 is subject to deformation. Depending on the stiffness of the foot element 4, this deformation may be more or less pronounced. The foot member 4 may also be executed ring or cup-shaped.

If the chair 1 is loaded asymmetrically, then the foot element 4 deforms and the guide axis 6.5 of the roller 8 inclines with respect to the standing surface 9, as in FIG Fig. 8B shown in detail. The inclination angle β is loaded chair 1 between 0 and 30 degrees. Preferably, the inclination angle is between 0 and 10 degrees. The spring-elastic effect results in this embodiment essentially from the elastic deformability of the foot element 4.

Another embodiment is in Fig. 9 shown. There is shown a chair 1 comprising a foot part comprising a vertical pillar 3 and a foot element with six legs 4. At each of the six legs 4, a roller 8 is mounted, each of the rollers 8 mounted to roll about a wheel axle 8.1 a suspension and is freely rotatably connected via a guide shaft 6.5 with the respective leg 4. The suspension of the rollers 8 is rigidly connected to the legs 4, ie the rollers 8 can rotate together with their suspension about the guide axis 6.5, but the inclination of the guide axis 6.5 with respect to the legs 4 is not variable. 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 make a pivoting movement and move apart radially. 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. By the ring member 4.1, the mechanical suspension of the legs 4 is protected and the ring member 4.1 causes a restoring force on the legs 4. When a load on the chair 1 performs at least one of the rollers 8 automatically from an immersion movement, in which the guide shaft 6.5 of this one roller with respect to a footprint changes its inclination β. As a result, at least one point of support of the chair 1 shifts to the outside.

The chair 1 after Fig. 9 is shown in an unloaded condition and the rollers 8 occupy a position at which the guide shafts 6.5 are substantially perpendicular or, if initial blocking is desired, are slightly inclined negatively. Due to the vertical or slightly negative slope, the degrees of freedom of the rollers 8 are not significantly limited and the rollers 8 follow easily each movement of the chair first

The spring-elastic effect results in this embodiment essentially from the special elastic support of the legs 4.

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

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

Additionally or alternatively, the legs 4 themselves can be made elastically deformable. The deformability can be achieved, for example, by a lateral torsion of the axes of the legs 4.

Preferably, the restoring force acting on the legs 4 of the chair 1 can be adjusted via a spring element (for example a spring) which is attached to the column 3. Such a spring 14 is in Fig. 9 shown. This spring 14 is optional. By means of such a spring, the degrees of freedom of the movement can be controlled by influencing an elastic element, which is arranged in the region of the column 3.

In the Figures 10A and 10B Details of another embodiment are shown. 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 spring of conventional design. The gas spring consists of elements 3.1, 3.2 and 3.3. By the gas spring, a seat of the chair can be adjusted in height. There are a total of five curved legs 4 are provided. At each of the five legs 4, a roller 8 is mounted, each of the rollers 8 is mounted rollably about a wheel axle 8.1 a suspension 6.1 and is freely rotatably connected via a guide shaft 6.5 with the respective leg 4. The suspension 6.1 of the rollers 8 is rigidly connected to the legs 4, ie the rollers 8 can rotate together with their suspension 6.1 to the guide axis 6.5, but the inclination of the guide axis 6.5 with respect to the legs 4 is not variable. The embodiment shown is characterized in that the legs 4 are suspended mechanically in relation to the column 3 in such a way that they make a pivoting movement when the chair is loaded and move radially apart from one another. The bearing comprises a ring element 4.1, which is arranged at the lower end of the column 3. Each of the legs 4 sits in a sleeve 4.2, as in Fig. 10B to recognize. For each of the legs 4 a separate pivot axis 4.3 is provided. These pivot axes 4.3 are preferably arranged tangentially to the cylindrical circumference of the column 3 and extend perpendicular to the central axis 11 of the chair. The ring element 4.1 has in the embodiment shown an upper ring 4.4 and a lower ring 4.5. Between these two rings, an elastic ring element 4.6 is arranged, 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 pivoting a leg 4, a 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 an influence can for example be realized in such a way that the elastic ring element 4.6 can not or only limitedly deform upwards under load from one of the legs 4. The rollers 8 sit in a suspension that is fork-shaped, as in Fig. 10B can recognize. The bearing of the rollers 8 is also eccentric here, ie the guide shafts 6.5 and the axles 8.1 do not intersect each other. The elastic effect results in this embodiment essentially from the special storage / suspension of the legs. 4

A further embodiment of movably mounted chair legs 4, which can be advantageously used in connection with the present invention, is disclosed in US Pat Figures 11A-11E shown in different views. The roles are in the Figures 11A-11E not shown. Fig. 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 pillar 3. Fig. 11B shows a partial section through a lower portion of the chair. In Fig. 11C is shown a plan view of the foot, in which the radial arrangement of the legs 4 can be seen. Each leg 4 is connected via a mechanical suspension 4.7 individually with an annular element 4.1. Fig. 11D is a section along the line AA and Fig. 11E is a section along the line CC. In these Sectional views show details of the mechanical suspension 4.7. Each of the legs 4 is connected via a clamping element 4.7, for example in the form of a steel cable, hingedly connected to the annular element 4.1. The clamping element 4.7 is seated in an elastic shell, which is shown in the figures dark gray. Depending on the tension of the clamping element 4.7, the "elasticity" of the suspension can be adjusted.

By the ring element 4.1 and the special design of the clamping elements 4.7 a restoring force acts on the legs 4. The elastic effect results in this embodiment essentially from the special storage / suspension of the legs. 4

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

A section through another chair 1 according to the invention is shown in FIG Fig. 12A shown. A schematic side view is the Fig. 12B refer to. The chair 1 has a plurality of legs 4, which are suspended mechanically with respect to a central pillar 3. At the upper end of the column 3, a seat 2 is arranged. The column 3 comprises a spring mechanism whose individual elements are not further described here. It should merely be noted that one can act by adjusting the hood 14.1 on the spring 14.2 so that the degrees of freedom of movement are controlled by influencing an elastic ring element 4.11. Such an influence can, for example, be realized in such a way that the elastic ring element 4.11 can not deform or only slightly deform upwards under load from 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 clamped between a lower annular element 4.10 and an upper annular element 4.9. The annular element 4.9 is preferably designed so that it yields when one of the legs 4 moves upwards, as in approaching in Fig. 12B can be seen. 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 be hung simply before the lower annular element 4.10 and the upper annular element 4.9 is used. Such a connection of the legs 4 with the column 3 can be done for example by means of a thru axle or the like. The elastic elements / segments 4.8 and 4.11 form, as in Fig. 12B 4. Now, when a leg 4 is pushed upwardly with respect to the pillar 3, for example when a user loads the chair 1, the chair leg 4 compresses the element / segment 4.11 and it raises a restoring force. In the example shown, the element / segment 4.11 is provided with an oblique 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. Preferably, an elastomeric ring 4.11 is used, which is cylindrical in the lower region and conically shaped in the upper region, wherein the conical part defines the surface 4.12. The elastic effect results in this embodiment essentially from the special storage / suspension of the chair legs. 4

Further details of such a chair are the aforementioned German patent application DE 10338549.1 taken on 19.08.2003 and entitled "pendulum chair".

In Fig. 13 a further preferred embodiment is shown. The foot of a chair is shown, which has a central pillar 3. The chair has six legs 4, four of which are visible in the view. Each of the legs 4 has an L-shape with the L lying and the short leg 4.16 of the L's parallel to the central axis 11 of the column 3. The long leg 4.15 of the L's runs substantially parallel to a standing surface 9. On the short leg 4.16 a plurality of spaced-apart recesses 4.13 are provided. The legs 4 are arranged around the pillar 3 so that an elastic, annular element 4.14 may comprise the six legs 4 and come to lie in the recesses 4.13. In the embodiment shown, the annular element 4.14 is seen in the second recess from above. Upwards and / or downwards, the legs 4 can be clamped by discs 3.4, 3.5 or the like. Depending on the position of, or number of annular elements 4.14 to change the lever arm and thus the hardness of the setting. The legs 4 can move radially in planes that are perpendicular to the central axis 11. These levels form an angle of 60 degrees with each other, if six legs 4 are provided. Optionally, an elastic ring or other elastic body may be positioned from below between legs 4. By such an element, an initial spread of the legs 4 can be specified. The spring-elastic effect results in this embodiment essentially from the special support of the legs 4 and the spring element 4.14.

Alternatively, or in addition, the legs 4 themselves may 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 may be telescopically extendable, for example.

Another embodiment is in the detailed view of Fig. 14 shown. A central column 3 has at the lower end a cylindrical extension 3.7, which is arranged concentrically to the central axis 11. Arranged around this cylindrical extension 3.7 is an elastic, bulbous element 3.6, which forms a cavity 3.9 in the example shown. The legs are connected to the elastic, bulbous element 3.6, as shown by 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 flexibility. By moving the leg 4, the inclination angle of the guide axis 6.5 changes. The element 3.6 may be provided with a valve 3.8, which allows to change the pressure in the cavity 3.9 and thereby the spring characteristic of the element 3.6 influence. Instead of a bulbous element 3.6, for example, a cylindrical, or a different shaped element can be used. The spring-elastic effect results in this embodiment essentially from the special suspension of the legs 4.

1. (1) er in unbenutztem Zustand gebremst wird, um beim Aufsitzen oder Anstossen des Stuhls nicht davon zu rollen. Das wird dadurch erreicht, dass die Führungsachse eine leichte negative Neigung (-5 < β< 0 Grad) aufweist;
2. (2) er beim zentrierten Sitzen (symmetrische Belastung) frei rollen kann;
3. (3) er bei einseitiger Belastung (asymmetrische Belastung) eine Bremswirkung entfaltet.

In a preferred embodiment, the chair is designed with serving as supporting elements rollers so that

1. (1) it is braked when not in use so as not to roll when sitting or bumping the chair. This is achieved by the guide axis having a slight negative slope (-5 <β <0 degrees);
2. (2) he can roll freely when centered sitting (symmetrical load);
3. (3) it exerts a braking effect on one-sided loading (asymmetrical loading).

All embodiments have in common that a dynamic sitting can be ensured by the elastic effect of the foot part. The movement of the 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.

All roll-based embodiments have in common that the guide axle and the wheel axle of a roller suspension are related to one another in such a way that the rollers change from a so-called unstable position into a so-called stable position when the chair is asymmetrically loaded. Through this transition (immersion movement), the degrees of freedom of the musculoskeletal system of the chair are reduced. This leads to the braking effect by which the chairs according to the invention are distinguished.

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 surface 9.

The effects of which the present invention makes use can be particularly clearly observed when the roles of the chair per se are unbraked, since the rollers then run freely during the immersion movement of the chair before they turn from a labile to a stable position (immersion movement) , In addition, the wheels, which are not slowed down, allow a particularly pronounced dynamic up and down motion.

There are no Silentgummis, brake pads or the role partially embracing brake bells required to produce the inventive braking effect. On the contrary, use of such brake media may under certain circumstances suppress the effects according to the invention.

The dip occurs when the angle of inclination, i. the angle of the guide axis 6.5 with respect to the vertical chair axis 11, depending on the load of the chair 1 changed.

Preferably, the inclination angle β of the guide shafts 6.5 of the rollers 8 with respect to the vertical axis 11 is between -5 and 30 degrees. Particularly advantageous is an inclination angle β between -5 and 10 degrees. For rounded rollers 8 (such as in FIG. 12A shown), the inclination angle β may be smaller than in rolls 8 or rollers whose edge regions are less round.

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 any of the figures, since it may be a variant of the various embodiments, the chair is designed to be assigned a defined seating direction. This can be achieved, for example, by the fact that the seat surface can not be turned relative to the base of the chair comprising the elements 3, 4, 6 and 8. 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 fixed, then the resilient action of the foot elements 4 can be set differently at the front than at the rear. For example, it is easier to bob forward with the chair than backwards.

A further embodiment is characterized in that an adjusting means 15 is arranged between the vertical column 3 and the legs 4, the attachment points of which can be displaced vertically along the column 3 and / or horizontally along the legs 4, as in FIG Fig. 15 schematically indicated by double arrows. As a result, depending on the location of the starting points, the initial spread can be set and / or the intensity of the voltage can be set. Preferably, the length of the adjusting means 15 or the hardness / elasticity of the same can be changed and there are slits 15.1, 15.2 provided for moving. In the region of the attachment points, the adjusting means 15 can be fixed, for example, after displacement by means of screws or the like. 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 in Fig. 16 shown. A perspective view of a foot part 5 is shown. An embodiment of a spring arrangement for the foot elements 4 is shown. In this embodiment, the foot elements 4 engage on a spring steel ring 20 by means of slots or the like. The spring steel ring 20 is slipped over an annular projection of an elastomeric spring 17, which has a disk-shaped element 18 at the top. In this embodiment, a washer may 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 on the leg tube 15, which is part of a column 3, or on a leg tube. The elastic effect results in this embodiment essentially from the special suspension of the legs 4. The legs 4 itself can be rigid or inherently resilient.

in Fig. 17 is a further embodiment of a Federanorndung for the foot part 5 is shown. In this embodiment, the spring assembly 17 is formed as a leaf spring assembly, in which one or more leaf springs 19 are arranged in the foot elements 4. In Fig. 17 schematically four leaf springs 19 different length associated with a foot element 4. The design, shape and number of leaf springs 19 is at the discretion of the expert, since these are adapted to the corresponding needs. For attachment, the illustrated construction may be provided from a pin plate 24 with clamping disk 25. Here, the pin plate 24 clamped with its upper flange 24 'and the lower clamping plate 25, the inner end of the leaf springs 19 together. A thread is provided at the free end of the pin 24 "onto which a nut is screwed to provide the necessary holding force." The overall package may be disposed in a hollow formation of a foot member 4. This makes it possible to use the leaf spring assembly 19 in plastic or plastic The elastic effect results in this embodiment essentially from the special embodiment of the legs 4, which act in themselves resilient.

Fig. 18 shows an arrangement in which a conical leaf spring 19 is completely embedded in a foot element 4 of plastic material having elastic properties. The elastic effect results in this embodiment essentially from the special embodiment of the legs 4, which act resiliently.

Fig. 19 shows a next embodiment, in which the foot member 4 is held by means of a hinge 26 to a joint bearing member 27 at the lower end of the leg part 3. In this embodiment, a slot 16 of the foot member 4 engage over a resilient ring, which is not shown for simplicity. The elastic effect in this embodiment results essentially from the special suspension of the legs 4. The legs 4 per se may be rigid or inherently resilient.

A next embodiment is in Fig. 20 shown in which the hinge struts 26 are replaced by one or more springs 26 '. In this variant, the foot member 4 can overlap with a slot storage, for example, as in Fig. 12A shown, an axle pin 14 ', which may be held stationary or by means of a suspension 14 "movable.The cap 17 can prevent jamming.The spring effect results in this embodiment essentially from the special suspension of the legs 4. The legs 4 at they can be rigid or elastic in themselves.

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

In Fig. 22 a further embodiment of the invention is shown. In this embodiment, the foot member 4 is divided into a movable part 4 'and a rigid part 4 ". The movable part 4' is hinged to the rigid part 4". A spring arrangement 19 is formed between the two parts 4 'and 4 "In the illustrated example, 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 opposite each other 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 thus experiences a restoring force. The elastic effect results in this embodiment essentially from the special embodiment of the legs 4, which act resiliently.

The offset between the guide shaft 6.5 and the wheel axle 8.1, which is referred to here as eccentric bearing, according to the invention is typically between 0.5 cm and 5 cm. Particularly advantageous is an offset between 1 cm and 3 cm. The choice of the appropriate offset is important, since neither in too small nor too large an offset occur the inventive effects of the braking effect. If the offset is too great, safety problems can occur, in particular if the guide axes have too great a negative inclination β, since in this case the rollers are too close to each other in the unloaded state. Particularly suitable are rollers that have a diameter between 1 and 8 cm. Here, rollers 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 stool. The individual components of the chair are the resilient legs, for example, caused by the action described in connection with the drawings 5A, 5B, 6A, 6B, or 7A, 7B.

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

A chair according to the invention not only exhibits the described braking effect if rollers are used, but generally increases its contact surface under load and, due to the runnability of the rollers or the sliding ability of the sliding elements, enables a virtually frictionless and secure up and down movement 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, dynamics, health and comfort.

Fig. 23 shows in axial sectional view another embodiment of a pendulum stool 1 with a seat part 2, a leg part 3 and foot elements 4, which project radially from a foot part 5. In the illustration, three such foot elements 4 can be seen. In realized embodiments, any number of such foot elements can be arranged on a foot part, usually between four and six. On the leg part 3, a spring assembly 6 is fixed, which allows up and down swinging of the seat part 2 on the foot part 5. In the illustrated embodiment, the foot elements are provided with rollers 8 at their free ends. However, this is an alternative embodiment, which is not mandatory, since there are also such pendulum stool, which are on sliding buttons. The lower part of the leg part 3 arranged foot part 5 has a holding arrangement 10, on which the foot elements 4 suspended substantially individually and are mounted up and swiveled.

In the foot part 5, a second spring arrangement 9 is provided, which cooperates with the holding arrangement 10. The holding arrangement 10 has in the illustrated embodiment over a circumference of 360 ° distributed holding segments 10 ', which define a free cross section and have a distance from each other. The spring arrangement 9 consists in the illustrated embodiment of an elastomeric ring inserted into the free cross-section, which widens cylindrically in the lower region and conically outwardly in the upper region. For this purpose, the retaining segments 10 'have a corresponding conical flattening. In the distance space between the segments 10 ', a pivot pin 14 is installed, on which, as will be explained later, the foot elements 4 can be hooked. In the free opening cross-section of the elastomeric ring in the foot part 5, the lower part of the leg part 3 is inserted and connected on its side facing the floor with a closure member 13 with the foot part.

In the in Fig. 23 illustrated embodiment, the leg part on an abutment plate 11, on which the first spring assembly 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. When in connection with the embodiment according to Fig. 26 and 28 used spring arrangement, this adjuster 7 also serves to adjust the restoring force to the extent of the desired pendulum motion.

Fig. 24 shows a pendulum stool in a perspective view obliquely from below. Thus one looks from below on the foot part 5 with the closure piece 13.

Fig. 25 shows a schematic representation of the arrangement of foot elements 4. In the foot elements 4 slot 16 are formed at the leg-side ends, which open downward. With this slot 16, the foot elements 4 are mounted on the axle 14. The inner end faces of the foot elements 4 are provided with a bevel 4 ', with which they rest against the conical outer surface 9' of the molded cone of the spring element 9. At the predetermined distance above the back of the foot elements 4, a cap 17 is arranged made of elastic material. Under the cap rollers 38 are provided, against which the back of the foot elements 4 and roll along during their pivotal movement. Since the cap 17 is set substantially translationally in the axial direction of the leg portion, it exerts a restoring moment on the respective foot elements 4, if they perform a pivoting movement upwards.

Fig. 26 shows a further embodiment of a spring assembly 9. In this arrangement, the spring assembly 6, which is mainly responsible for the up and Abschwingbewegung the stool, with in the provision of the spring forces for the restoring moments acting on the foot elements 4 acts. For this purpose, the spring 6 is supported via the plate 11 on a transfer plate 6 'on the ring of retaining segments 10' from. When a foot member 4 performs a pivoting upward, so presses its inclined surface 4 'against the conical spring mass of the ring 9 and urges this material upwards, and the material would like to expand and in turn pushes against the transfer plate 6 ', which is supported against the abutment plate 11. However, since this abutment plate 11 is spring-loaded, acts on a spring element 4, which is pivoted upwards, both the restoring force of the spring assembly of the material 9 and the force of the spring 6, so as to 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 body segment assembly 10 in this embodiment.

In Fig. 27 is a perspective view of the support assembly 10 with six retaining segments 10 'and an inserted annular elastomeric spring assembly 9 is shown.

The holding arrangement consists, as already in connection with Fig. 23 explained, in the illustrated embodiment of annularly arranged holding segments 10 ', each having a predetermined distance, measured in degrees from each other. In each case, a holding arrangement is formed between the individual holding segments, in the illustrated embodiment an axle bolt 14. These axle bolts 14, which are respectively inserted into the spacing areas, join the holding segments 10 'together to form a retaining ring. At the inner edge of this retaining ring on the retaining segments 10 'in each case an inclined surface 10 ", which considered in the totality of all holding elements form a conical bearing surface for the conical upper portion 9" of the elastomeric spring ring 9. Accordingly, the elastomeric spring ring 9 is formed in the illustrated embodiment as a one-piece elastomeric ring, which is enclosed in its lower portion by the cylindrical portions of the retaining segments 10 ', that is applied to the cylindrical portion of the holding elements 10' and in the upper region a conical extension has, which rests on the conical surfaces 9 '.

At the in Fig. 26 illustrated embodiment, the plate 6 'in diameter substantially designed so that it rests in the region of the upper inner edges of the retaining segments 10'.

On the other hand, in the case of Fig. 28 illustrated embodiment in which the tube assembly of the leg part 3 and the foot part 5 are shown in the sectional detail, the support surface of the spring 6 on the elastomeric material of the spring assembly 9 substantially lower. The diameter of the transfer plate 6 'is slightly smaller than a recess in the overlying abutment plate 11. In the abutment plate 11 is a bore, the clear width is dimensioned so that the tube 15 of the leg part 3 can pass and with appropriate loading a sitting on As a result, the leg part undergoes a spring-soft stop position with maximum compression of the spring.

In the case of a pendulum movement, ie a lifting of a foot (not shown in this example), the elastic material 9 presses upwards and consequently the transfer plate 6 'in the recess of the abutment plate 11. Between the transfer plate 6' and the abutment plate 11 can be an elastic Be arranged intermediate layer. This embodiment allows a gimbal of the leg tube, which passes with a pipe extension 15 'through the elastic ring 9 and is fixed to the lower side of the support assembly 10 by means of a screw 19 on the bracket. In this case, a screw connection, not shown, is supported via a shim structure 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 by means of the slots 16 on a spring steel ring 20 at. The spring steel ring 20 is as out Fig. 30 can be seen, slipped over the annular projection of the elastomeric spring 9 and closes flush with this at the bottom edge. 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 means of a screw connection to the leg tube 15 or to a leg tube 15 '. On the leg tube 15 'a counter-disc 11 "set, which provides an abutment for the evading elastomeric material 9.

The foot element 4 preferably has at its lying between the slot 16 and the leg end lower edge of a chamfer 22, which allows the foot member 4 to pivot upward without the washer 21 counteracts.

In one embodiment, not shown, may be formed on the foot member 4 integrally formed on the leg end radially projecting projection which instead of oblique surfaces with a downwardly directed surface a substantially vertically downwardly directed pivoting force on the elastomer ring 9 exerts. In such an embodiment, the elastomer ring 9 may be formed as a simple elastic tube sleeve with a correspondingly thick wall thickness, which receives the pivoting force by means of its upwardly directed end wall.

At the points at which a foot member 4 engages over the steel spring ring 16, a corresponding recess 23 is provided on the elastomer ring, to allow the overlap of the steel spring ring 20 through the slot 16.

In Fig. 31 a further embodiment of a spring arrangement for the foot part 5 is shown. In this embodiment, the second spring arrangement 9 is designed as a leaf spring arrangement in which one or more leaf springs 9 "are arranged in the foot elements Fig. 31 schematically four leaf springs 9 "of different length associated with a foot element 4. The design form and the number of leaf springs 9" is at the discretion of the skilled person, since they are adapted to the respective needs. For attachment, the illustrated construction may be provided from a pin plate 24 with clamping disk 25. In this case, the bolt plate 24 clamps with its upper flange 24 'and the lower clamping disk 25 the inner end of the leaf springs 9 "together." At the free end of the bolt 24 ", a thread is provided, onto which a nut is screwed 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 embed the leaf spring assembly 9 in plastic or an elastomer.

Fig. 32 shows an arrangement in which a conical leaf spring 9 is completely embedded in a foot member of plastic material having elastic properties.

Fig. 33 shows a next embodiment in which the foot member 4 is held by means of a hinge 26 to a joint bearing member 27 at the lower end of the leg part 3. In this embodiment, the slot 16 of the foot member 4 engage over a resilient ring; which is not shown for the sake of simplicity.

A next embodiment is in Fig. 33a shown in which the hinge struts 26 are replaced by one or more springs 26 '. In this variant, the foot member 4 with the slot 16 overlap a storage, for example, as in Fig. 23 shown, a pivot pin 14, which may be held stationary or by means of a suspension 14 'movable.

Fig. 34 shows a next embodiment of a spring assembly 9 on the foot part 5. In this embodiment, the foot elements 4 substantially in the shape of an L with a bottom leg 29 and a vertical leg 29 ', wherein the horizontal bottom leg 29 is formed longer than the vertical leg 29th '. In the angular range of the foot element, a spring arrangement 9 is provided, which acts on the one hand on a corresponding retaining projection 30 under the horizontal leg of the foot member 4 and the other on the leg part 3. Furthermore, each of the foot members 4 is pivotally supported via a suspension 28 in this angular range. In a pivoting movement, the foot member 4 is pushed upwards and rotates about the suspension 28. At the same time acting by the spring assembly 9 restoring force, which causes a moment against the pivoting or pendulum movement of the chair.

All upwardly directed legs are covered by the cap 17 and secured against unintentional trapping of objects.

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

Fig. 36 shows a next embodiment of the embodiment according to. Fig. 34 , In this variant, the upwardly projecting legs of the foot elements 4 are 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 at the outwardly directed back of the vertical leg 29' of the foot member 4 in bearing grooves 31 arranged there. In order to change the strength of the restoring moment, the ring 9 '''can be arranged at different levels. The larger or smaller distance to the suspension 28 'results in a larger or smaller return torque. The closer the ring is arranged on the suspension 28 ', the lower the restoring moment; conversely, it increases with the distance to this suspension.

In addition to the elastic ring 9 '''can, as in Fig. 34 represented, consisting of an elastic material cap 17 cause a resilient restoring moment, if in the embodiment according to. Fig. 36 is screwed over the upwardly projecting leg 29 'of the foot elements 4. In a deflection of a foot member 4, this abuts the edge of the cap 17 and must overcome the rest of the cap caused by this elastic cap as the pendulum movement continues,

Fig. 37 shows a next embodiment in which the upwardly projecting legs of the L-shaped foot members 4 bear against a central wedge 32 at their inwardly directed edges. This central wedge is axially displaceable along the leg part and allows for precise initial angular adjustment of the rollers on the foot parts 4. A suitable suspension keeps the foot elements in position.

Another embodiment with L-shaped foot elements 4 is in the Figs. 38a and 38b played. In this embodiment, the spring force for the restoring torque of the foot elements 4 is provided by a spring ring 9 ^IV , which is arranged substantially formed as a foot ring on the back of the horizontal leg 29. The diameter of this spring ring 9 ^IV is chosen so that it comes to rest essentially on the outer regions of the foot elements 4.

The cross section of the foot ring 9 ^IV can be designed in a special way to provide a desired restoring force. In the embodiment gem. Fig. 38a has the spring ring g ^IV in cross section a z. B. approximately egg-shaped form, which provides a high relative to the cross-section restoring moment of the ring itself. However, it can also find a flat lying ring use, which has a softer return characteristic.

A next embodiment is in FIGS. 39 and 40 shown. In this embodiment, the foot part 5 is formed by an elastic hollow body 33, on the outer sides of the foot elements 4 are fixed substantially rigid. 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, thereby allowing a foot member 4 attached thereto to perform a substantially spatial pivotal 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 tubular extension 15 'has a retaining plate 36, on the underside of retaining webs 37 are provided, between which the axle pin 14 is attached. In the region of the outer circumference, a disk-shaped spring arrangement 9 is fastened under the retaining disk 36, against which the back 4 'of a foot element 4 rests. At a distance above the axle pin 14, a stop 38 is provided below the retaining disk 36, by which it is ensured that the foot member 4 can not disengage from the axle pin 14 during dynamic rocking movements.

The spring assembly 9 consists in the illustrated embodiment of a spring ring 9 ^V , which has a three-layer structure. It can be with these three layers may be any combination of different hard or soft elastomers, for example, the lowermost layer may consist of a non-elastomeric material, and it may, as in Fig. 20 illustrated, a certain geometry of the contact surfaces of at least two layers may be provided, which makes it possible to adjust by rotating the two respective layers by a predetermined angle a different spring characteristic.

In the in Fig. 42 shown setting, the elastomeric ring 9 ^V , which consists of an elastic material, the largest spring strength. If you now turn the uppermost layer by so many degrees, that both layers are offset by half a ramp length; Thus, one allows the elastomeric material of one layer, or, if it is both layers to such an elastomeric material, and the other layer to partially escape into the space created, resulting in a softer spring constant of the overall ring result.

In a particular embodiment, these specially designed contact surfaces, which in Fig. 42 have a coarse sawtooth pattern, in addition to a very fine sawtooth pattern, see Fig. Detail, be equipped, thereby preventing that a twisted in a predetermined position spring washer back rotates due to the dynamic movement.

An alternative embodiment of such an elastomeric ring 9, as in the embodiments according to FIGS. 41 and 42 may be that a rubber hose is used whose hardness 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 likewise formed on a sleeve on the tube part 15 'of the leg tube 3. On the sleeve, the foot elements 4 are arranged pivotably about the axle pin 14. On the leg-side end face of the foot member 4, a pressure plate 39 is arranged. At an upward pivoting movement of the foot member 4, this pressure plate 39 pivots in the direction of the pipe section 15. At the height of the working area of the pressure plate 39, an elastomeric ring is placed around the pipe part 15, so that the pressure plate 39 more or less depending on the extent of pivotal movement of this ring 9 strongly compressed. The elastic deformation exerts a restoring moment on the pressure plate and thus on the base element 4.

At the radially outer ends of the foot elements 4 are in the in FIGS. 43-45 illustrated embodiments stopper 40, which are located radially outside the contact surfaces between the bottom and roller 8.

While at the in Fig. 43 illustrated embodiment, the stopper 40 is arranged rigidly on the foot member 4, the stopper 40 in which in the FIGS. 44 and 45 illustrated embodiment, an integral part of the roller suspension, ie, the stopper 40 forms an extension of the rotation axis 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 43rd Roll / floor and center of the stool; if the roller is pivoted inwards, then the stopper 40 is outside this measure. The end portion of the foot member 4 or the roller support may be so soft or articulated to a certain extent that in the pendulum load the rollers 8 "turn off" and thus the stoppers 40 can come into contact with the ground. As a result, a braking effect is achieved and the chair can not roll away.

At the in Fig. 46 illustrated embodiment, the stopper 40 is rigidly always within the distance Stool center / role. In this way, the stopper 40 with its rubber stud 41 always come into contact with the ground when the pendulum tendency in the direction of the foot member 4 exceeds a certain number of degrees. The reason for this is that when swinging forward, the hinge point of the suspension of the foot member 4 on the support assembly 10 approaches the ground, a relative upward swinging motion of a foot member 4 occurs, but the angle between the foot member 4 and the floor becomes smaller. Also at in Fig. 47 illustrated embodiment, the stopper 40 is within the distance Stool center / role, namely in the immediate vicinity of the leg part tube 15. The stopper 40 here has the shape of a skirt whose outer edge is supported with a corresponding inclination of the leg part (3) on the ground.

This particular stopper assembly provides a safety feature that prevents the stool from rolling under the user in the direction opposite to the pendulum swing during excessive pendulum motion. In contrast, causes the stopper assembly, which is radially outside of the contact point 43, a larger angle between the foot member 4 and the bottom, so that due to this inclination of the outer stopper 40 comes into contact with the ground and thus holds the stool in place. This effect also occurs with the foot elements facing the one in the direction of which the pendulum motion is being performed. These remote foot elements also take a steeper angle of the bottom surface, resulting in a contact of the outer stopper 40 with the ground.

It is expressly understood that any combination of the embodiments shown in the description are possible and thus in the realization of non-described embodiment combinations, the scope of protection of the patent is not abandoned. Thus, it is for example possible that the stopper cooperates with any construction of a spring arrangement, so it is not limited to the embodiment Fig. 43 ,

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

In Fig. 49 a further embodiment variation of the invention is shown. In this embodiment, the foot member is divided into a movable part 4 'and a rigid part 4 ". The movable part 4' is articulated to the rigid part 4". Between the two parts of the second spring assembly 9 is formed. In the illustrated embodiment On the underside of the foot element 4, there is provided a hinge 44 serving as a hinge between the movable part 4 'and the fixed part 4 ".The opposing parting surfaces of the parts 4' and 4" together form a V-shaped cutout, in FIG In the case of a pendulum load, the movable part 4 'provides against the resistance force of the compression spring 9 "and in this way experiences a restoring moment.

It will be understood that this embodiment is not limited to the compression spring 9 "arranged in the V-cutout, so that a leaf spring may 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.

In principle, any other spring construction can be chosen which allows a restoring moment to be exerted between the parts 4 'and 4 "when the movable part 4' makes a relative pivoting movement as a result of the pendulum movement with respect to the fixed part 4".

Claims (2)

1. Pendulum chair having a seat portion (2), a single central leg portion (3), a foot portion (5) arranged thereon at the bottom end and having a predetermined plurality of foot elements (4), and having at least one first spring arrangement (6) interacting with the seat portion (2), wherein
   at least one determined of the foot elements (4) thereof is formed movable and, when loaded, is applied with a resilient restoring torque,
   the foot elements (4) are arranged substantially star-shaped, and the foot elements (4) are substantially individually pivotable up and down, wherein
   a second spring arrangement (4.11, 9) engages at least one specific foot element (4), wherein
   restoring means (4.8, 4.9, 4.10, 4.11, 4.12) are provided for applying a restoring force of the second spring arrangement (4.11, 9),
   at least one holding arrangement (4.10-4.12) interacting with the second spring arrangement (4.11, 9) is formed on the foot portion (5) in the lower region of the at least one leg portion (3), said holding arrangement (4.10-4.12) containing at least one of the foot elements (4), and
   at least one substantially downwardly open slot (16) is formed on at least one leg end of at least one of the foot elements (4),
   is attached to the holding arrangement (4.10-4. 12) and retained in position with at least one counterpart.
2. Chair (1) having at least one single central leg portion (3) and at least one foot portion (5) having a predetermined plurality of foot elements (4), wherein at least one support element (8) is connected to each of the foot elements (4), wherein
   at least one of the foot elements (4) thereof is designed in such a way that, when the chair (1) is loaded, said chair executes a spring-soft lowering movement, in which at least one supporting element (8) moves with respect to a standing surface and, as a result, a supporting point of the chair (1) defined by the position of the at least one supporting element (8) with respect to a central axis (11) of the chair (1), is displaced outwards,
   the foot elements (4) are arranged substantially star-shaped, and the foot elements (4) are substantially individually pivotable up and down and wherein
   a second spring arrangement (4.11, 9) engages at least one specific foot element (4),
   wherein restoring means (4.8, 4.9, 4.10, 4.11, 4.12) are provided to apply a restoring force of the second spring assembly (4.11, 9),
   at least one holding arrangement (4.10-4.12) interacting with the second spring arrangement (4.11, 9) is formed on the foot part (5) in the lower region of the at least one leg portion (3), said holding arrangement (4.10-4.12) containing at least one of the foot elements (4), and
   at least one substantially downwardly open slot (16) is formed on at least one leg end of at least one of the foot elements (4),
   is attached to the holding arrangement (4.10-4. 12) and held in position with at least one counterpart.

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