EP0539733A1 - Chair, in particular rotatable office chair - Google Patents

Abstract

In a chair, a seat-part support (11) and a backrest support (12), which is adjustable in inclination, are connected movably to effect a synchronous adjusting movement taking place relative to the frame (10). The backrest support engages at its lower end (12a) below the seat-part support and is connected to it for simultaneous movement by means of at least one connecting element. In a transfer movement initiated by the motion of the body of the chair-user, the backrest support is lowered while the seat-part support is simultaneously moved forwards and lowered at least in its rear part (11b). Due to the fact that the backrest support (12) and the seat-part support (11, 111, 211) transmit their movement onto the connecting means and onto one another at points on the connecting means which are spaced apart and are guided on the frame despite being bound to paths which are independent of one another, the backrest support being lowered at least slightly further than the seat-part support in the connection region to the seat-part support during the transfer into the rest position, a high-quality chair is produced in a cost-effective manner, which chair can be transferred into a rest position which is as comfortable as possible. <IMAGE>

Description

The invention relates to a chair, in particular an office swivel chair according to the preamble of claim 1.

Such a chair is known from DE-OS 39 30 983, in which the seat part support is moved forward and downward in a synchronous movement and the backrest support is inclined. The movement takes place via synchronous levers, which require a complex construction. Backrest support and seat part support are also connected to one another via a swivel axis, so that the two parts cannot be moved independently of one another. Although the relative movement between the backrest and the seat part, which promotes the shirt pull-out effect, is largely reduced by the synchronizing lever provided with several articulation points, it cannot be completely eliminated due to the connection of the two carriers.

From DE-OS 26 42 091 it is known to guide the lower end of a backrest support in an arch-shaped guide engaging under the seat. The guides can be designed both as sleeves and as guide rollers that roll in corresponding elongated holes. The backrest support moves around an imaginary axis that is laid through the user's hip joints. However, due to the fact that the seat part carrier cannot be moved forward and thus no shift in the user's center of gravity can be achieved, only a limited inclination of the backrest can be carried out. Furthermore, when moving to the rest position, it is uncomfortable that the seat part carrier does not lower at least in its rear part. This promotes the shirt pulling effect, which is caused by a Relative movement of the backrest support compared to the back of the user is caused.

From ER-PS 0 303 720 a chair is also known in which an L-shaped backrest support is transferred in two guides from a working position to a rest position. The upper end of the backrest support moves downward and at the same time the seat part support connected to the backrest support directly via a pivot axis is moved forward and slightly downward in the rear part. However, the seat part support is undesirably raised at the front due to the arrangement of the front guide of the backrest support required for the tilting movement. Due to its L-shape, the backrest support is tilted into two guides, which then still allow movement about an imaginary axis, but which due to the large radius specified by the guides is largely stationary at chest or stomach height and a short distance from the seat user . However, since the backrest support and seat support have a common swivel axis, independent movement of both elements is not possible.

Chairs are also known (EP-OS 36 824; WO 87/06810), in which the movement of the seat and backrest relative to one another about an imaginary axis takes place through the user's hip joints. These chairs are not intended to shift the center of gravity. In addition, it is difficult to guide the backrest support in the arch on the seat part support, since this can easily lead to the backrest support breaking through, so that adjustment mechanisms are provided which do not permit free movement of the backrest support.

Based on this prior art, the invention has for its object to develop a chair of the type mentioned in such a way that an aesthetically sophisticated chair is realized in a cost-effective manner, which allows the transfer to a comfortable rest position as possible.

This object is solved by the features of claim 1.

Basically, the required comfort of a chair is determined by how far the backrest can be tilted backwards. The relation of backrest / seat pressure in case of induced load changes during "dynamic sitting" can be considered a comfort-determining factor. In the case of an office chair, this maximum possible inclination is fundamentally limited by the permissible projection of the backrest, since if the backrest is inclined without simultaneously moving the seat part carrier forward, the center of gravity is moved so far away from the axis of rotation that there is an increased risk of tipping. Furthermore, it is desirable that the chair moves downward simultaneously with its rear part of the seat part carrier when the backrest is inclined, in order not to obtain a relative movement between the seat part and the backrest which promotes the pulling out of the shirt. In principle, such a movement would be readily possible if the backrest and seat part carrier are moved together on a circular path. However, this would undesirably raise the front part of the seat part with the support zone of the front thighs, which can lead to swelling of the legs and to sensations such as "falling asleep" and "tingling".

According to the invention, the center of gravity is now shifted forward when the backrest inclination is adjusted by the forward movement of the seat part carrier, so that even greater inclinations can be realized safely without the need for cantilevered outriggers for support at the foot of the chair. The seat part carrier is moved independently of the backrest carrier, so that the undesired lifting of the support zone of the thighs is avoided. Rather, the prerequisites for an ergonomic principle following horizontal movement of the front edge of the seat, which remains at almost the same height, are created.

The shirt pull-out effect, which causes a seat user to take off his shirt when he tilts the backrest part backwards with the aid of a body motor and thereby leans with his back against the backrest, is based on a relative movement between the backrest and the back of the user, in which usually the backrest moves upward relative to the user's back. In contrast, will now not only reduced this relative movement to zero, but rather also lowered the backrest support more than the seat part support, so that, in contrast to known chairs, the backrest support now moves downwards relative to the back of the user, i.e. the shirt is put on him.

This results in comfortable seating with the possibility of being transferred to a reclined position. In every intermediate or end position of the sliding process of the seat shell, which is guided smoothly by guiding the backrest support and seat part support on different tracks, the active possibility of a weight-shifting change in posture, the so-called "dynamic sitting", is offered. Extensive freedom of movement with extreme sitting (lying) inclination of the trunk axis (spine) combined with safe and pressure-minimized support of the body weight through large contact zones of the anatomically shaped seat shell allow maximum relaxation of the abdominal and diaphragm muscles with a positive effect on the achievable depth of breath and Cardiac output. As a result of relaxation and circulation, there is a noticeable increase in seating comfort that promotes health. The seat part carrier is moved on a separate path regardless of the circular movement of the backrest carrier. The sagging of the backrest support occurring under circular guides of the backrest support can be counteracted, so that apart from the body movement of the user hardly any aids are required for transferring to the two end positions.

In an embodiment according to claim 2, the sliding process superimposed on the sliding process, continuous movement sequences about an (invariable to the user) axis are possible with continuous load changes in the contact zones (buttocks / back) also open up new freedom of movement and the seating comfort of the user with arcuate guidance of the backrest support be increased. A guide along an arch is to be understood to mean a guide that either has arch-shaped elements on the backrest support that are moved along stationary bearings of the frame, or that on Backrest support has bearings that are moved in arcuate guides of the frame, regardless of whether the arc is a circular arc or the section of a hyperbola, parabola or a similarly curved section of a geometric line.

If, according to claim 3, the axis about which at least the backrest support moves is arranged at the level of the imaginary axis between the hip joints of the user, then a relative movement between the person and the chair is reduced.

In an embodiment according to claims 6 and 7, a roller can be used for permanent guidance on a career in that this roller rolls along its circumference to reduce friction only at small points. If the roller moves out of its centered position, the outwardly decreasing diameter leads to self-centering, since the larger diameter that occurs during a lateral movement tends to reset itself like rollers on appropriately shaped railroad tracks. If the track is designed accordingly, an increased relative movement between the seat part carrier and the backrest carrier is produced during the initial transfer movement from the working position.

In an embodiment according to claim 8, a band or rope is provided as a connecting means between the backrest support and the seat part support, which is also connected to the frame. In combination with the running track, an optimal transfer movement can be achieved and the belt can still be held in any position.

In an embodiment according to claims 9 and 10, an axis is provided at the stationary point of the frame, which can influence and coordinate the desired relative movements between the backrest support and seat part support by appropriate shaping. As a connecting element, windable tapes, ropes or the like can be used. Due to the stretching characteristic, a rope is preferably wound on a part of the axis during the transfer movement and unwound on the other part of the axis. Of course, two ropes and two different axes can also be used.

A special coordination possibility arises when the axis is divided into two sections that have different diameters. Since the backrest support has to move relatively more strongly during the transfer movement than the seat part support which is moving at the same time, a larger diameter is provided on the section of the axle assigned to the backrest support, as a result of which the required windings of the cable for the backrest support can also be arranged in a narrower space. The axle also serves as a guide roller for the seat support, which ensures the drive of the axle. According to claim 11, a single rope can be used, which is simply inserted in the axis through a central bore with radial access openings on one side of the bore and exits on the other side of the bore.

All embodiments have in common that due to the few means required, the entire chair mechanism can be covered with little effort so that it also meets the highest aesthetic standards, since a slim chair silhouette can be achieved without further ado.

The invention is explained in more detail below with reference to the drawings in several exemplary embodiments.

Fig. 1:

Den in Arbeitsstellung befindlichen Stuhl in Seitenansicht in einer ersten schematisch dargestellten Ausführungsform,

Fig. 2:

den Stuhl gemäß Fig. 1 in Ruhestellung,

Fig. 3:

eine Abbildung gemäß Fig. 1 und 2 wobei der Stuhl in Ruhestellung gestrichelt dargestellt über den Stuhl in Arbeitsstellung gezeichnet ist,

Fig.4,5:

eine vergrößerte, schematische Darstellung des Betätigungsmechanismus' in Arbeitsstellung bzw. Ruhestellung,

Fig. 6:

eine schematische Darstellung von Rolle und geschnittener Laufbahn in einer Seitenansicht gemäß Fig. 5,

Fig. 7:

einen vergößerten Ausschnitt in einer Fig. 1 entsprechenden Darstellung mit einem weiteren Verbindungsmittel,

Fig. 8:

eine Aufsicht auf die linke Hälfte des Stuhles in einer schematischen Darstellung, wobei zur Klarheit der obere Teil der kreisbogenförmigen Führung des Rückenlehnenträgers entfernt ist.

Fig. 9:

eine vergrößerte Abbildung des unteren Abschnittes von Fig. 3,

Fig. 10:

den Stuhl gemäß Fig. 1 in einer weiteren Ausführungsform,

Fig. 11:

den Stuhl gemäß Fig. 1 in einer dritten Ausführungsform.

Fig. 12;

einen vergrößerten Ausschnitt einer Führungsschiene,

Fig. 13

einen vergrößerten Ausschnitt der Führungsschiene aus Fig. 2 mit darin befindlichem Verstellglied,

Fig. 14

eine Aufsicht auf den am Gestell angeordneten Verstellmechanismus

Show it:

Fig. 1:

The chair in the working position in a side view in a first schematically illustrated embodiment,

Fig. 2:

1 in the rest position,

Fig. 3:

1 and 2, wherein the chair is shown in dashed lines in the rest position over the chair in the working position,

Fig. 4,5:

an enlarged, schematic representation of the actuating mechanism in the working position or rest position,

Fig. 6:

3 shows a schematic illustration of the roller and the cut career in a side view according to FIG. 5,

Fig. 7:

2 shows an enlarged detail in a representation corresponding to FIG. 1 with a further connecting means,

Fig. 8:

a plan view of the left half of the chair in a schematic representation, the upper part of the circular-arc guide of the backrest support is removed for clarity.

Fig. 9:

3 shows an enlarged illustration of the lower section of FIG. 3,

Fig. 10:

1 in a further embodiment,

Fig. 11:

1 in a third embodiment.

Fig. 12;

an enlarged section of a guide rail,

Fig. 13

3 shows an enlarged section of the guide rail from FIG. 2 with the adjusting element located therein,

Fig. 14

a top view of the adjustment mechanism arranged on the frame

The pictures show the chair, which is preferably used as an office swivel chair in three exemplary embodiments. To differentiate the reference numerals of the individual exemplary embodiments, the reference numerals of the second and third exemplary embodiments are distinguished from the first exemplary embodiment in that, in the case of corresponding parts, a 1 is given in front with respect to the reference numerals or 2 is set in advance, ie they are increased by 100 or 200 compared to the first embodiment.

All of the exemplary embodiments have in common that a seat part support 11, 111, 211 and a backrest support 12, 112, 12 which is adjustable in inclination are movably connected to the frame 10, 110, 210 in a synchronous adjustment movement relative to the frame. At its lower end 12a, 112a, 212a, the backrest support engages under the seat part support. During a transfer movement initiated by the user's body motor from an upright working position to a rest position, the upper part 12b, 112b, 212b of the backrest support 12, 112, 212 is lowered. Seat part carrier 11, 111, 211 and backrest carrier 12, 112, 212 are connected to one another by means of a connecting element in such a way that when the transfer movement into the rest position, the backrest carrier in the connection area 12c, 112c, 212c to the seat part carrier is at least slightly more lowered than that at the same time forward and in the rear part 11b, 111b, 211b seat part carriers moved downwards. The backrest support and seat support support transmit their movement to one another and to a connecting element by being connected to it at two spaced apart points, so that they can move on two mutually independent tracks.

During the transfer movement, the backrest support is guided under an arch under the seat part support, the transfer movement achieved thereby taking place approximately around an imaginary axis M at the level of the user's hip joints.

During the transfer movement, the seat part carrier 11, 111, 211 basically moves forward (FIG. 3). By arranging the guide elements for the seat part carrier, this movement takes place below a horizontal plane hh, which is determined by the highest point P of the seat part carrier in its working position. For the front guidance of the seat part carrier, a guide pin or a guide roller 14, 114 is provided on the frame 10, 110, on which the seat part carrier 11, 111, 211 is guided with an elongated hole guide 11d, 111d. Of course, this principle can also be reversed, i.e. with an elongated hole guide on the frame, which is inclined forward to avoid raising the front edge of the seat. In contrast, in the exemplary embodiments, the elongated hole guide 11d slides past the guide roller with a change in inclination. Alternatively, however, the seat part carrier 11 can also be articulated on the frame 10 via at least one pendulum support, each with a joint assigned to the frame and the seat part carrier, which should already be inclined forward in the working position. In the side view, the backrest support 12 merges from an arch arranged at the bottom (guides 12d) into the upper, almost straight part 12b, on which the backrest 25 is articulated on the joint 12f, 112f.

As can be seen from FIGS. 1 to 3, the backrest support 12 has at its lower end 12a at least one circular-shaped guide 12d which is guided on at least two bearings 13 arranged in a stationary manner on the frame 10. The radius of the circular arc enables movement around the imaginary axis. However, it is also possible to provide the backrest support 12 at its lower end 12a with an arc-shaped guide sleeve which engages around a horn fixed to the frame 10 at least at one point and which has the same radius as the guide sleeves.

During the transfer movement taking place with the backrest support 12, the seat part support 11 moves on a path that is independent of the backrest support. For this purpose, the seat part support 11 has at its rear end 11b at least one roller 17 which rolls on the track designed as a track 18. The schematic FIG. 6 shows the self-centering principle of the symmetrical roller 17, which is guided on an axis 11c of the seat part carrier 11. For this purpose, the track 18 provided on the frame 10 has a central recess groove 18a into which the roller is immersed with a central radial rib 17a. The roller is designed in the form of a roller, its diameter decreasing linearly outwards, starting from the radial rib 17a, which has the largest diameter of the roller 17. As a result, only a small part of the roller rolls on the Career from and the roller is automatically returned from an off-center position to its centered position, since the outwardly decreasing diameter of the roller-shaped roller forces the roller to reset itself due to the larger diameter that occurs on one side during a lateral movement.

The track 18 is wave-shaped (Fig. 4.5). Starting from the position of the roller 17 in the rest position, it is initially convex and then concave when it is transferred to the working position. This initially provides resistance to the chair's initial effort to sag along the arch under load. However, this also leads to an increased relative movement between the seat part support and the backrest support, especially at the start of the transfer movement, which even slips on the shirt of the user.

As can be seen from FIGS. 4 to 6, the backrest support 12, the seat part support 11 and the frame 10 are connected to one another via a rope or band 19 which is fastened to the backrest support 12 in the region of the curved guides 12d and to the rear edge 10c of the frame 10. As an alternative to connecting the three elements seat part support 11, backrest support 12 and frame 10, which are operatively connected to one another, there is the possibility of using a preferably cable or band-shaped connecting element which is fastened to two of these three parts and is movably connected to the third part.

The indirect connection of seat support 11 and backrest support 12 with a band requires that the band is always kept under tension, which is ensured by appropriate training of the track 18 in all positions of the chair. Depending on the point of application of the strap on the outer or inner radius of the arch, a greater or lesser disproportionate pivoting of the backrest support is achieved. The belt at least partially wraps around the axis 11c fastened to the seat part carrier 11 clockwise or counterclockwise, which allows a further possibility of fine adjustment of the adjustment possibilities.

FIGS. 7 and 8 show a further connection with a cable 19 'which is connected to the backrest support 12 at a pivot point 12g via a front section 19b'. The rope is connected to the seat part carrier 11 by a rear section 19a ′ at the articulation point 17d of an axis 17c of the guide roller 17.

The connection to the frame 10 takes place via an axis 15 ′ which is fixed to the frame 10 and carries a roller corresponding to the guide roller 13, at least with regard to its diameter. The two parts 19a ', 19b' of the rope 19 'are connected to this axis. The axis 15 'has an inner section 15a' which lies outside the guide rail of the circular guide 12d of the backrest support and an outer section 15b 'which lies within the circular guide 12d. On the inner section 15a ', the part 19a' of the rope 19 'assigned to the seat part carrier 11 is wound up or unwound, while on the outer section 15b' the front part 19b 'of the rope 19' is unwound or unwound at the same time.

When moving to the rest position, the rear part 19a 'of the rope is wound up and the front part 19b' of the rope 19 'is unwound, since in this case the guide roller 17, which guides the seat part carrier on a track 18, comes closer to the stationary axis 15 . The outer section 15b of the axis 15 has a larger diameter than the inner section 15a. As a result, the relative movement between the backrest support and the seat part support can be coordinated and the cable sections are always kept under tension.

The axis 15 'mounted on the frame 10 has a central bore 15e' which is accessible via radial access openings 15c ', 15d'. This hole allows only one rope to be used to link all three parts. During production, the rope is inserted through one opening 15d 'and exits through the hole 15e' from the other opening 15c '. When making the hole the axis is drilled from one side and then the radial holes are made. When assembling the chair, the axle with its inner section 15a 'is mounted on the frame, then the backrest support is attached to the axle sections 15' and the guide roller 13, and the outer section 15b 'is then fastened to the axle by threaded connections. If the axis 15 'also represents a guide roller 13 for the circular-shaped guides 12d of the backrest support 12 (FIG. 7), the backrest support can simultaneously drive the stationary axis and thus move the seat part support.

In the second exemplary embodiment shown in FIG. 10, the seat part carrier 111 is arranged in the rear part 111b on at least one lever 116 which is articulated on the frame 110 and which is articulated on the joint 111c on the seat part carrier and which is actuated by the backrest carrier 112. The backrest support 112 is connected to the seat part support via a connecting element and has at its lower end 112a an actuation profile 115 which engages on a guide 120 of the lever 116. During the transfer movement, the lever which is initially slightly inclined forward is actuated by the lowering backrest support 112, the forward movement of the seat part support being initiated. The molded on the backrest support profile presses on the guide designed as a guide roller, so that the two parts roll on each other. Depending on the design of the profile, a separate lowering of the seat part carrier can be achieved, so that the profile e.g. career 18 can be mimicked.

Such an imitation of the career 18 is also possible, for example, with a design according to the third exemplary embodiment shown in FIG. Here, the backrest support 212 and the seat support 211 are assigned racks 211f, 212e, which mesh with at least one gear 221,222. Either two gears with different sprockets are used, as shown, or the distance between the teeth of the respectively assigned gear and rack is differentiated, so that here too the disproportionate pivoting is realized.

In a manner not shown in the drawing, the seat part carrier 11 can also be guided only at the front end 10b of the frame 10 in two guides which absorb the load on the seat part carrier 11 and which bring about the desired movement independent of the backrest carrier. In this case, you only have to use any auxiliary device, e.g. the band 19 the indirect connection between the seat support and backrest support are made. An indirect connection via an elastic spring, preferably a metal tongue, is also possible, which is dimensioned for a sufficient number of load cycles and allows a separate transfer of the seat part carrier.

Although the chair can easily be kept in balance in any position, particularly in the case of an embodiment according to the first exemplary embodiment, there is nevertheless the possibility of moving the transfer movement into the rest position against the force of a (compression or tension) spring 24 or a gas spring 24 ' (Fig. 9) perform, which engages the frame 10 and the front end of the seat support 11.

All of the exemplary embodiments have in common that the maximum pivoting angle α of the backrest support between the rest position and the working position is approximately 2.5 times as large as the angle of inclination β of the seat part support 11, 111, 211 that occurs. In order to enable the chair to be fixed in any desired position, recesses 12h spaced apart from one another in the guide direction can be provided in the guides, preferably guide 12d or slot guide 11d of the seat part carrier. An adjusting member 27 can be pivoted into these recesses and can be pivoted about an adjusting axis which is arranged transversely to the guide rail and plunges into the latter. The position of the adjusting member 27 changes during the transfer movement relative to the guides, so that a latching in the recesses 12h is possible due to the pivoting movement of the adjusting member.

The adjustment axis 26 of the adjustment member 27 is mounted on the frame 10 in a stationary manner and the backrest support 12 has the circular-shaped guide 12d with the recesses 12h. The adjustment axis 26 extends through either the guide slot already formed by the mounting of the guide rollers 13 or a separate guide slot 12k. The recesses can either be arranged on the walls 12 l of the guide 12d or on the base 12m of the guide. In the latter case, the guide reason is also used as a grid adjustment. In any case, the mutually offset recesses are arranged on both sides of the guide slot at regular intervals and are each at a diagonal distance which corresponds to the length of the adjusting member 27 with its two pivot arms 27a. In the non-operative position, the adjusting member 27 can be arranged approximately parallel to the walls of the guide slot 12k, so that the adjusting member "slides" in the guide slot 12k.

The pivot arms 27a rest in the locking position on a side surface 27b on a flank 12h of the recesses. The actual locking takes place, as can be seen from FIG. 3, by abutting the end faces 27c of the swivel arms 27a on the respective other flank 12h ″ of the recesses 12h. During the pivoting, a pivoting movement of approximately 45 ° takes place, the rectangular pivot arms 27a being driven into the triangular recesses 12h.

As can be seen from Fig. 14, the pivoting movement is triggered by a lever 28, which is located under the seat of the chair. This lever is under the force of a spring so that it is automatically returned to the locking position. However, it can also be locked out of the active position.

Reference symbol list (not part of the registration documents)

10,110,210

frame

10a

Articulation point from 19th

10b, 110b

front end

10c, 110c, 210c

rear edge

11,111,211

Seat part carrier

11a, 111a, 211a

Connection area at 12

11b, 111b

back part

11c

Axis for 17th

111c

Articulation for 116

11d

Slot guide

111e

Linkage for 112

211f

Rack

12,112,212

Backrest support

12a, 112a, 212a

lower end

12b, 112b

upper part

12c, 112c, 212c

Connection area at 11

12d

circular arc-shaped guide

212e

Rack of 212

12f, 112f

Articulation point backrest

12g

Articulation point from 19th

12h

Recesses

12h ', 12h' '

Flanks

12k

Guide slot

12l

Wall

12m

ground

13.213

warehouse

14.114

front guide roller of 11.111

15 '

axis

15a '

inner section

15b '

outer section

15c ', 15d'

Access openings

15e '

drilling

17th

role

17a

Radial rib

17b

Outdoor area

17d

Articulation point for 19th

18th

career

18a

Deepening groove

19, 19 '

Tape or rope

19a '

back part

19b '

front part

24.24 '

feather

25th

backrest

26

Adjustment axis

27

Actuator

27a

Swivel arm

27b

Side surface

27c

Face

28

lever

115

Actuation profile

116

lever

120

guide

221.222

Gears

M

Axis through the user's hip joints

h-h

horizontal plane

P

highest point of 11 in working position

α

Swivel angle of 12

β

Inclination angle of 11

Claims (14)

Chair, in particular office swivel chair with a frame (10, 110, 210), with which a seat part support (11, 111, 211) and an inclinable backrest support (12, 112, 212) are movably connected to a synchronous adjustment movement relative to the frame, the backrest support at its lower end (12a , 212a) engages under the seat part support (11, 111, 211) and is connected to the seat part support for simultaneous movement by means of at least one connecting element, with a transfer movement initiated by the user's body motor being lowered from an upright working position of the chair into a rest position of the backrest support while the Seat part carrier simultaneously moves forward and at least lowers in its rear part (11b, 111b, 211b), characterized in that the backrest carrier (12, 112, 212) and seat part carrier (11, 111, 211) are located at spaced apart points of the connecting means (band 19, 19 ', elastic spring, gear 221, 222) transmit their movement to the connecting means and also to one another and, despite the connection, are guided on the frame on mutually independent paths, the backrest support being at least slightly stronger when transferred into the rest position in the connection region to the seat part support lowers as the seat support. Chair according to claim 1, characterized in that the backrest support (12) is guided under an arch under the seat part support. Chair according to claim 1 or 2, characterized in that the transfer movement takes place approximately around an imaginary axis (M) which passes through the hip joints of the user, the seat part carrier (11) moving approximately below a horizontal plane (hh) passing through the highest point (P) of the seat part carrier (11) is determined in its working position (Fig.3). Chair according to one of the preceding claims, characterized in
that at least one guide pin is provided on the frame (10), on which the seat part carrier (11) is guided with an elongated hole guide (11d). Chair according to one of claims 1-4, characterized in that the backrest support (12) has at its lower end (12a) at least one circular arc-shaped guide (12d) which is guided on at least two bearings (13) arranged in a stationary manner on the frame (10) is. Chair according to one of claims 1-5, characterized in that the seat part support (11) has at its rear end (11b) at least one roller (17) which rolls on a track (18) on the frame (10) and the one in the middle Has deepening groove (18a) into which the symmetrical roller (17) guided on an axis (11c) of the seat part carrier (11) with a central radial rib (17a) is immersed (FIG. 6). Chair according to claim 6, characterized in that the diameter of the roller-shaped roller (17) outwards, starting from the radial rib (17a), which has the largest diameter of the roller (17), decreases linearly and the raceway (18) is undulating is and starting from the position of the roller (17) in the rest position of the chair when moving into the working position is initially convex and then concave. Chair according to one of the preceding claims, characterized in that the backrest support (12), seat part support (11) and frame (10) are connected to one another via a connecting element designed as a rope or band (19, 19 '), which is connected to at least two of the three elements Frame (10), seat part support (11) and backrest support (12) attached and movably connected to the third of these elements. Chair according to claim 8, characterized in that the rope or band (19, 19 ') is firmly connected to the seat part support (11) and backrest support (12) and to the frame (10) via a stationary axis (15, 15) mounted on the frame ') is movably connected, which is at least partially wrapped around by the connecting element. Chair according to claim 9, characterized in that the axis (15 ') has an inner section (15a') assigned to the seat part support (11), from which the rear part (19a ') of the rope or band (19') designed as a connecting element ) is unwound when it is transferred to the working position, and has an outer section (15b ') associated with the backrest support (12), on which the front part (19b') of the rope or band (19 ') is wound when it is transferred to the working position , wherein the diameter of the inner section (15a ') is smaller than the diameter of the outer section (15b'), and that the axis (15 ') also serves as a guide roller for the backrest support (12) which drives the axis during its transfer movement . Chair according to one of claims 9-10, characterized in that the axis (15 ') has a centrally arranged bore (15e) connecting the two sections (15a', 15b ') with radial access openings (15c, 15d) leading to the Recording and fixing at least one rope is provided. Chair according to one of claims 1-4, characterized in that the seat part carrier (111) is arranged in the rear part (111b) on a lever (116) articulated on the frame (110), which lever is guided by the backrest carrier (112) via an actuation profile (115 ) is actuated, which engages on a guide (120) of the lever (116) articulated on the seat part carrier (111) (FIG. 10). Chair according to one of the preceding claims, characterized in that seat part supports (11) and / or backrest supports (12) are guided on guides (slot guides 11d, guide 12d), which have spaced-apart recesses (12h) in the guiding direction and that an adjusting member (27) is provided which can be pivoted about an adjusting axis (26) which dips transversely to the guide rail, the position of which relative to the guides changes during the transfer movement, and this by means of a pivoting movement about the Adjustment axis (26) in the recesses (12h) for fixing the chair in any position can be controlled. Chair according to claim 13, characterized in that the adjusting axis (26) of the adjusting member (27) is stationary on the frame (10) and that the backrest support (12) has an arcuate guide (12d) on which the recesses (12h) are provided and the at least two bearings (guide rollers 13) which guide them and which are stationary on the frame (10) pass through to form a guide slot (12k) which is also penetrated by the adjustment axis, the guide (12d) having two walls (12l), which have the mutually offset recesses (12h) at regular intervals and that the guide slot (12k) is arranged at the bottom of the guides and is removed with the recesses (12h) from the bottom of the guide (12d), about half of the bottom ( 12m) is designed as a guide slot.

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