WO2000024294A1

WO2000024294A1 - Chair with a backrest

Info

Publication number: WO2000024294A1
Application number: PCT/IB1999/001725
Authority: WO
Inventors: Emilio Ambasz
Original assignee: Vitra Patente Ag
Priority date: 1998-10-22
Filing date: 1999-10-22
Publication date: 2000-05-04
Also published as: EP1039817A1; EP0995376A1; CA2316368A1

Abstract

The rest part (51) of the backrest (5) is supported by two front legs (1, 1') projecting through a horizontal cross-tube (3). The seat plate (4) is placed on the cross-tube (3) by means of brackets which are fixed or which can pivot around a main axis (D). Elastic bridge pieces (500, 500') are inserted between the rest part (51) and the rest element (10, 10'), and the rest part (51) is also elastic. In an alternative embodiment, the rest part (51) and the bridge pieces (500, 500') construct a component part. The chair can be completed with armrests (8, 8') which can be inserted into the cross-tube (3). The arm supports (82, 82') of said armrests can horizontally pivot in order to stack a number of chairs next to one another. In a completely equipped embodiment, a pivotal side table (9) is eccentrically arranged on an armrest (8) and comprises a tilt-swivel mechanism and means for safeguarding against overstressing. The side table (9) falls into the vertical non-use position when overstressed. Coupling elements are provided on both sides of the cross-tube (3) for forming rows of interconnected chairs.

Description

Chair with backrest

Field of application of the invention

The invention relates to a four-legged chair with a backrest, which can be stacked to save space. In a further embodiment, the seat plate of the chair can be folded up. As an option, armrests, a swivel-in shelf and a full range of coupling elements for connection with the row connection to the neighboring chairs can be attached. The four legs of the chair are attached to the side of the seat plate and preferably on a transversely arranged support tube, the front legs protruding from the seat plate. Such chairs are used in particular at mass events or when the seating offer can be expanded spontaneously.

PRIOR ART Stacked and foldable chairs in various designs have been known for some time. A type according to CH-A-562 591 has two U-shaped legs, the upper ends of which are connected in two joints. A swiveling, semicircular backrest is fastened in these joints. On each side, a tab extends between the legs, which is articulated on the front leg and hangs on a pin on the rear leg, which runs in a longitudinal slot of the tab. When the legs are folded together, the pins move forward in the longitudinal slots, the tabs swivel upwards at the rear and the seat plate lowers at the front. Disadvantages here are the very narrow, hardly supportive backrest and the uncomfortable armrest on the front area of the backrest.

A folding chair with two U-shaped legs is known from NL-A-8 401 170, the rear leg being articulated below the seat plate, while the front leg extends into the backrest in its extension. At the rear, the seat plate is articulated at the transition between the front leg and backrest. The front and rear legs are connected in an X-shaped and articulated manner below the seat plate. When the legs are folded, the seat plate swivels in the vertical direction towards the backrest. This folding chair does not offer the option of attaching armrests through modular additions and the backrest cannot be folded in, so that the chair is also bulky during transport or when parked.

DE-A-29 30 140 proposes a folding chair where the front and rear legs, seat frame and back and armrests are pivotally fixed together in two nodes lying on an axis. The nodes represent complex articulated connections that have to be tensioned or released by the user.

The folding chair according to WO-A-88 06019 also has two U-shaped legs, which are X-shaped and articulated below the seat level. Cross struts extend between the legs at the front and rear, to which a flexible seat cover is attached. A bow-shaped armrest, which engages behind the backrest, is articulated to the upper ends of the rear leg, which is connected to the upper ends of the rear leg projecting. When the legs are folded up, the seat cover folds up and the armrest swings downwards. This chair is not very suitable for long periods of sitting, as the backrest is only a small height, has little support due to its fabric covering and the seat is also formed by a flexible, flexible covering.

EP-A-0 365 012 shows a folding chair with two front legs and a bow-shaped arm attached to the floor. Armrests projecting to the rear are articulated at the upper ends of the front legs, which merge into the backrest and are bent upwards. Between the front legs, a seat plate is rotatably supported below the armrest, which hangs at the rear on two articulated vertical struts, which are rotatably fastened at the transition between the armrests and the backrest. Folding is done by swiveling the armrests up, which also pulls up the seat plate. When folded, this chair with its bulky frame takes up a lot of space, so that it is also little for individual transport suitable is. Furthermore, the backrest with the textile covering and the upper, transverse backrest arch is not optimally supportive for longer sitting.

US-A-4 278 287 describes a folding chair with a U-shaped curved front leg and a bow frame, the lower part of which forms the rear leg and the upper part of which forms the backrest. The upper ends of the front leg are hinged to the backrest and the seat frame to the rear leg. There is a cross strut on the front leg on which the covered seat frame rests. When folded, the front leg and frame come to one level and the seat falls down. This chair also has a bulky frame with the disadvantages mentioned and the armrests designed as side struts hardly fulfill this function

WO-A-89 00390 proposes a collapsible chair with two front and two rear legs, a seat plate and a backrest. The seat plate is articulated on the front and rear legs. The backrest is articulated at the upper ends of the front and rear legs. In the set-up state, the four legs are spread like a goat, the seat plate extends horizontally and the backrest vertically, the articulation point between the seat plate and the front legs being above the second, rear articulation point of the seat plate. The point of articulation between the backrest and the front legs is above and in front of the second articulation point of the backrest, so that the front legs extend upward over the rear legs. When the chair is folded, the legs, the seat plate and the backrest lie in one plane and the articulation points are rearranged. The front edge of the seat plate and the upper edge of the backrest swivel downwards, at the same time the upper ends of the rear legs protrude above the upper ends of the front legs. Armrests are missing on this chair for longer, comfortable sitting and the rigid backrest is not very comfortable.

Another collapsible chair is disclosed in DE-A-30 16 685. Here the upper ends of the front and rear legs are articulated together connected. The rear part of the seat is articulated to the backrest, while the seat is supported by the front legs. The armrests rest on the articulated connection between the legs and are articulated to the backrest. When folding, the backrest is moved onto the seat and into the level of the rear legs, causing the articulated connection to buckle on the armrests. By loosening the front legs attached to the seat, these and the seat can be folded in. The legs of different lengths and the slight overlap of the chair parts when folded together result in a bulky, unwieldy frame. The rigid backrests formed by a slatted frame will already be felt as hard after a short sitting, so a back cushion is recommended.

Finally, the subject of EP-A-0 835 619 is a chair that can be dismantled with a seat part, a backrest part and rod-shaped feet. The seat part has a seat shell with, in principle, vertically arranged pipe sections. On the backrest part there are pipe sockets complementary to the pipe sections. In the pipe socket there is a receiving contour in which a counter contour provided at the upper end of the feet can be fixed when the feet protrude through the pipe pieces with their upper plug-in part. The receiving contour and the countercontour are preferably formed by an internal thread and an external thread complementary thereto. The advantage of this chair is the space-saving storage when disassembled. Once set up, the seat plate cannot be folded up and the backrest is not ideal for long periods of sitting.

Object of the invention

In view of the imperfections described above, the object of the invention is to propose a chair with a well-supporting backrest, which can be flexibly adapted to the individual body contours and body movements. The chair should be stacked - one above the other and leaned against each other - to save space. In completed modifications, the seat plate of the chair should be foldable, armrests and a pivoting shelf must be attachable and a quickly detachable connection to neighboring chairs must be realized in order to form To facilitate rows of chairs. Elementary principles are that the chair stands firmly when the user takes a seat and stands up, general stability and consideration of ergonomic criteria. The chair should be able to be mass-produced in a rational manner and at low cost. Finally, the construction must enable a design that corresponds to the taste of the time.

Overview of the invention

An essential feature of the invention are elastic bridging pieces within the overlong front legs of the chair, which also support the elastic backrest part. The bridge pieces are either inserted between them as separate components or are connected in one piece to the backrest part. The front legs protrude through a cross tube on which the seat plate is fixed or folded up. In the version with a fixed seat plate, these supporting brackets are rigidly attached to the cross tube. In the foldable version, the brackets can be swiveled by means of rotary bearings fixed in the cross tube.

To complete the chair, armrests and their supports are inserted into the cross tube. The armrests can be swung out horizontally for stacking several chairs. For this purpose, a spring-loaded swivel mechanism is inserted between the armrest and the support supporting the armrest - this is attached to the top of the support - which pulls the armrest onto the support.

With maximum equipment, an armrest, preferably to the right of the user, has an eccentric swivel side shelf with the insertion of a tilt-swivel mechanism. The tilt-swivel mechanism is equipped with an overload safety device so that when the side shelf is turned, cams with inclined surfaces disengage against the resistance of a spring and the side shelf falls into the vertical rest position. Coupling elements are arranged on both sides of the cross tube to form rows of interconnected chairs. The chair according to the invention is distinguished by its utility properties with solid stability, good seating comfort, easy handling and small space requirement due to its stackability. The chair can be set up in a row with neighboring chairs and can be mass-produced in a rational manner.

Brief description of the accompanying drawings.

Figure 1A: a chair according to the invention as a whole, in the use position, as a perspective view;

Figure 1 B: the chair according to Figure 1A with a foldable seat plate (rest position) put together with a second chair, as a perspective view; 1C: the chair according to FIG. 1A with a second chair, per se in the use position, one above the other, as a perspective view;

Figure 2A: a backrest to be attached to the base of the chair;

FIG. 2B: the chair according to FIG. 1A with a seat cushion to be applied to the seat plate; FIG. 2C: the chair according to FIG. 1A with a backrest cushion to be applied to the backrest part;

Figure 3A: a base of the chair according to Figure 1A as a perspective view; Figure 3B: a pivot bearing with console and attached seat plate, as a partial section; Figure 3C: the pivot bearing with bracket according to Figure 3A and a cross tube, separated from each other, as a perspective view; Figure 3D: a seat plate according to Figure 3B, as a perspective partial section;

FIG. 4: a front and rear leg inserted into the cross tube with a cover cap, right side of the chair, as a perspective view;

Figure 5A: an armrest with armrest support and armrest as a whole, as

Partial cut; FIG. 5B: the swivel mechanism of the armrest as an enlargement from FIG. 5A, as a partial section;

Figure 5C: the pivoting of the armrest as a schematic diagram; Figure 6A: the chair according to Figure 1A in the use position, completed with armrests according to Figure 5A and a side shelf, as a perspective view; FIG. 6B: an attached side shelf according to FIG. 6A, pivoted away in the rest position, as a perspective view;

FIG. 6C: the horizontal joint of a tilt-swivel mechanism on the side shelf according to FIG. 6A, in the swiveled out position, as an exploded view; FIG. 6D: the representation according to FIG. 6C, with the side shelf in the pivoted-in use position, as an exploded view;

Figure 6E: the vertical joint of the tilt-swivel mechanism on the side shelf according to Figure 6A, as an exploded view;

FIG. 6F: the vertical joint according to FIG. 6E, put together as a top view;

FIG. 6G: the side shelf attached to the armrest in accordance with FIG. 5A with the tilt-swivel mechanism in the use position, as a vertical section;

FIG. 7A: a pair of coupling elements from two adjacent chairs according to FIG. 1A, as a perspective illustration; and

Figure 7B: the coupling elements according to Figure 7A, as a vertical section.

Embodiment

The detailed description of an exemplary embodiment of the chair according to the invention with its completion options is given below with reference to the accompanying drawings.

The following definition applies to the entire further description: if reference numerals are included in a figure for the sake of clarity in the drawing, but are not explained in the directly associated description text, reference is made to their mention in previous or later figure descriptions. In the interest of clarity, the repeated designation of components in the following figures is mostly dispensed with, provided that it can be clearly seen in the drawing that the components are "recurring". To avoid figures overloaded with reference numbers and Adherence to the systematics, the parts present symmetrically on both sides of the chair are fully listed here in the description, but are only mentioned alternately in the figures.

Figure 1A

The chair has a right and a left front leg 1,1 'as a base and a right and a left rear leg 2,2'. The legs 1, 1 '; 2.2' sit on the floor in a bock-like manner, spread out, the straight front legs 1, 1 'protruding through a supporting cross tube 3 at the top and the rear legs 2,2' to the front legs 1, 1 'offset inwards, are attached to the cross tube 3. A seat plate 4 is placed on the cross tube 3 between the back parts 10, 10 'of the front legs 1, 1' 'projecting beyond the cross tube 3. The rear legs 2, 2' are preferably attached to the cross tube 3 by welding, as are the front legs penetrating the cross tube 3 1, 1 'are welded to the cross tube 3. The legs 1, 1', 2.2 'are advantageously made of tube material. The seat plate 4 is either rigidly attached to the cross tube 3, for example welded, or can be folded up by additional components.

The backrest 5, which consists of a right and a left side strut 50.50 "and the backrest part 51, which spans between the two side struts 50.50 ', is placed on the open ends 100, 100" of the backrest section 10, 10'. The side struts 50, 50 'have an at least sectionally elastic bridge piece 500, 500' which lies between the upper end 100, 100 'of the backrest section 10, 10' and the connection to the backrest part 51. Each side strut 50, 50 'advantageously has an upper and lower plug end 501, 501'; 502, 502 'which attaches to the bridge piece 500, 500'. Here, the upper plug ends 501, 501 'are inserted on both sides into the backrest part 51 and the lower plug ends 502, 502' into the open upper end 100, 100 'of the backrest section 10, 10'. The ergonomically shaped backrest part 51 is also elastic, so that when leaning against the backrest 5, the bridge pieces 500, 500 ', adapted to the load exerted by the user and his body shape, yield resiliently in all directions and the backrest part 51 also experiences an elastically adapted deformation . Figures 1 B and 1C

In the embodiment with a movable seat plate 4, the chairs can be placed close together in a space-saving manner when the seat plate 4 is folded up, so that the back of a chair faces the front of the neighboring chair and the rear legs 2.2 "laterally into the spread legs 1, 1 '; 2.2' protrude.

If chairs are stacked on top of one another, the seat plates 4 are horizontal; this form of stackability is possible regardless of whether the seat plates 4 are foldable or not. The pair of front legs 1, 1 '- these have a further distance than the rear legs 2,2' - protrude down next to the seat plate 4 of the chair below. The front legs 1, 1 'of all the chairs stacked one on top of the other lie on a horizontal plane, as do their rear legs 2,2'.

Figures 2A to 2C

This sequence of figures shows various modifications with regard to the elastic bridge pieces 500, 500 'at the transition between the upper ends of the front legs 1, 1' and the backrest part 51 and the upholstery of the seat plate 4 and backrest part 51.

For reasons of the efficiency of the production of the chair parts and the subsequent assembly, it can be advantageous not to manufacture the bridge pieces 500, 500 'as separate components with upper and lower plug ends 501, 502, but in one piece together with the backrest part 51, preferably in plastic. fabric spraying process. This results in a backrest 5 with a backrest part 51 and side struts 50, 50 'in the form of directly attached bridge pieces 500, 500', which, aligned downwards, align with the open ends 100, 100 'of the backrest section 10, 10' of the front legs 1, 1 ' extend. As before, these bridge pieces 500, 500 'have lower plug ends 502, 502' for insertion into the open ends 100, 100 '. The lower plug ends 502, 502 'are fixed in the open ends 100, 100' by clamping form fit and possibly additionally by a securing element, for example a screw 101.

It is optically advantageous if the cross sections of the bridge sections 500, 500 ', the legs 1, 1', 2.2 'and the connection part on the backrest part 51, quasi their side struts 50, 50', are designed essentially the same, so that there are harmonious transitions from the ends 100, 100 'of the front legs 1, 1' to the bridge pieces 500, 500 'and from here to the backrest part 51. For example, an oval chair can be used to create an elegant chair. The bridge pieces 500, 500 'point in the visible area, i.e. as a separate component between their upper and lower plug ends 501, 501 '; 502.502' or, in the case of one-piece construction, with the backrest part 51, a rib structure 503 down to the lower plug ends 502, 502 '. This rib structure 503 is created by numerous radially circumferential grooves at systematic intervals. For the bending characteristic of the bridge pieces 500, 500 'and thus of the entire backrest 5, it is favorable to successively reduce the depth of the grooves, from groove to groove up to the backrest part 51 and possibly also to the lower plug ends 502,502'. In addition to the bending curve optimized in this way, there is also less material weakening at the places of the highest stress within the bridge sections 500, 500 '.

In order to make sitting on the chair longer for longer, the seat plate 4 can be provided with a cushion 42, which consists of a lower plate-shaped cushion carrier 420, the padding 421 applied on top and a cover 422. The cushion 42 is fastened, for example, practically by means of screws 423 engaging through the seat plate 4 in the cushion support 420. Analogously, the backrest part 51 can be equipped with a cushion 52, which consists of a rear plate-shaped cushion support 520, the padding 521 applied on the user side and one Coating 522 exists. The upholstery 52 is fastened in a similar manner, for example again by means of screws 523 which engage into the upholstery support 520 through the backrest part 51. Figure 3A

Two brackets 6 spaced apart from one another are placed on the cross tube 3 and serve to hold a seat plate 4 attached to the brackets 6. In a simplified version, where the seat plate 4 cannot be folded up, the brackets 6 are rigidly connected to the cross tube 3, e.g. welded. In the case of a foldable seat plate 4, however, the brackets 6 are pivotally mounted about the main axis D.

FIGS. 3B and 3D. On the underside of the seat plate 4, an open pocket 40 is provided on the one hand for the main axis D and on the other hand a fastening web 41 for the main axis D. The console 6 has a plug end 60 on one end face and, opposite this, a shaft end 61. In the assembled state, the plug end 60 is pushed into the pocket 40 and the shaft end 61 is connected to the fastening web 41, e.g. screwed. For the chair version with a fold-up seat plate 4, the bracket 6 has 7 bearing tongues (62) for receiving the pivot bearing around both sides. Advantageously, the console 6 consists of a U-profile open at the bottom.

Figure 3C

The roller-shaped rotary bearing 7 is fixed on the main axis D in a jacket recess 31 in the cross tube 3. The rotation lock is achieved by a flag 32 bent into the jacket recess 31 by the cross tube 3 and an indentation 73 on the curved jacket surface of the pivot bearing 7. The flag 32 is screwed into the recess 73. The two side surfaces 70 of the rotary bearing 7 are penetrated by the main axis D. There are 70 stop shoulders on the side surfaces. 71.72. From the bracket 6, the two bearing tongues 62 encompass both side surfaces 70 of the pivot bearing 7, so that the advantageously used two brackets 6, 6 'on the main axis D are pivotally fixed about the pivot bearings 7 positioned in the cross tube 3. In each case one of the two flanks 620, 621 on the bearing tongues 62 strikes against the stop shoulders 71, 72 in the folded use position or in the folded rest position of the seat plate 4, which is both End positions of the foldable seat plate 4 defined. An axle pin is used to fasten the bearing tongues 62 to the pivot bearing 7. On the outer part of the cross tube 3, complementary openings 301, 302 for inserting the front legs 1, 1 'or for inserting the rear legs 2,2' are provided for the spread position of the legs 1, 1 ';2.2'.

Figure 4

The rear leg 2 inserted into the openings 302 of the cross tube 3 offers an upwardly open insertion opening 200 for inserting an armrest; if such is not provided, the insertion opening 200 is closed for aesthetic reasons with a cover cap 38 which has a pin 380 and a screen 381, the screen 381 encompassing the upper side of the cross tube 3 and the pin 380 being inserted in the insertion opening 200.

Figures 5A to 5C

An armrest 8 initially consists of a support 80, the plug end 800 below which is intended for insertion into the insertion openings 200, 200 ', which are provided on the rear legs 2, 2' and as an opening in the cross tube 3. The fixation against pulling out occurs e.g. by screwing from the side of the cross tube 3. The support 81, which holds the armrest 82, attaches to the support 80 at the top.

A pivot mechanism 83 with the axis of rotation D1 sits between the carrier 81 and the armrest 82. The pivot mechanism 83 aims to pivot the armrest 82 outward from the use position about the axis of rotation D1 into the rest position. In the rest position, the armrest 82 is pivoted out so far that it does not hinder the stacked next higher chair. Arranged around the axis of rotation D1, the swivel mechanism 83 has a spring 830, against the force of which the armrest 82 can be swiveled out of a locking device 831 in the use position. This lock 831 can also act in the rest position of the armrest 82. In a practical embodiment, the locking device 831 consists of a nose 820 projecting on the underside of the armrest 82 and a complementary counter-contour 810 present on the top of the carrier 81. Figures 6A to 6G

On one of the armrests 8,8 "- preferably from the view of the user sitting on the chair on the right armrest 8 - a side shelf 9 is mounted, which by means of a tilt-swivel mechanism 90 from the vertically hanging rest position to the horizontal use position in front of the The tilt-swivel mechanism 90 consists of a horizontal joint 91 and a vertical joint 92 attached to it at an angle. The horizontal joint 91 is composed of a base sleeve 910 with a stop cam 911 and a sleeve piece 912 arranged eccentrically below the side shelf 9 Recess 913. The sleeve piece 912 sits with its recess 913 on the base sleeve 910 and the stop cam 911 moves when the side shelf 9 is pivoted horizontally within the recess 913. The base sleeve 910 and the sleeve piece 912 are for locking the use position of the side shelf 9 Locking elements 914.914 'v A secured axle bolt 915 extends upright through the base sleeve 910, onto which the sleeve piece 912 is attached, so that the side shelf 9 can be lifted off.

The vertical joint 92 of the tilt-swivel mechanism 90 consists of a receiving sleeve 920 and an insertion pin 922 inserted into the receiving sleeve 920, which can be pulled out to a limited extent against a spring 924. The receiving sleeve attaches 920 to the upper end of the support 80 of the armrest 8. The insertion pin 922 is angled onto the base sleeve 910 of the horizontal joint 91. A wedge cam 921 is arranged on the receiving sleeve 920 and a wedge-shaped complementary cam 923 is arranged on the insertion pin 922. Wedge cams 921 and complementary cams 923 work together as overload protection.

In the event of overloading, the insertion of the side shelf 9 and the associated sliding together of the wedge contours of the cams 921, 923 pull the insertion pin 922 partially out of the receiving sleeve 920 against the resistance of the spring 924. Finally, the compliment skips Tämocken 923 the wedge cam 921 and the side shelf 9 falls into the vertically hanging rest position.

Figures 7A and 7B in a row of chairs placed side by side can be quickly hooked into each other, so that a systematic seating of a larger area is achieved with the same spacing and the individual chair has better stability. For this purpose, mutually complementary coupling elements 39, 39 'are fixedly arranged on the cross tube 3 on both outer sides penetrating the main axis D, which quasi extend the cross tube 3 on both sides. The coupling element 39 on one side of the chair has an undercut pin 390 that extends in the direction of the main axis D. The coupling element 39 'on the other side of the chair has an undercut engagement 390' for hanging the pin 390, the hanging being done from above. The attachment of the coupling elements 39, 39 'is e.g. realized by screwing axially from the outside.

Claims

Patent claims

1. Chair, resting on a base (1, 1 '; 2.2'; 3), and with: a) a seat plate (4), and b) a backrest (5) with a backrest part (51), this is intended to support the user seated on the seat plate (4), characterized in that c) the backrest (5) on the base frame (1, 1 '; 2.2'; 3) with bridge pieces elastic in all directions ( 500,500 ') is attached; wherein d) the bridge pieces (500, 500 ') are inserted as separate parts or are a fixed, lengthening component of the side struts (50, 50') of the backrest (5). e) the backrest part (51) is made of resilient material.

2. Chair according to claim 1, characterized in that a) the base frame (1, 1 ';2.2'; 3) is formed from: aa) a right and a left front leg (1,1 '), ab) one right and left hind legs (2,2 '), and ac) a supporting cross tube (3) through which a horizontal main axis (D) extends; and b) the separate bridge pieces (500, 500 ') above the seat plate (4), on the one hand, into the back parts (10, 10 ") of the front legs (1, 1") projecting upwards over the seat plate (4), in the ends (100, 100 ') and, on the other hand, are inserted into the backrest part (51) with plug ends (501, 501'; 502.502 ') provided on the bridge pieces (500, 500'); or c) the bridge pieces (500, 500 ') connected in one piece to the backrest part (51) above the seat plate (4) into the backrest parts (10, 10 ") of the front legs (1, 1") projecting upwards from the seat plate (4), in whose ends open at the top (100, 100 ") are inserted with the lower plug ends (502, 502 ') provided on the bridge pieces (500, 500'), the bridge pieces (500, 500 ') merging into the backrest part (51) at the top.

3. Chair according to claim 1 or 2, characterized in that a) the legs (1,1 '; 2,2') like a goat, spread on the floor; b) the front legs (1, 1 ') are attached to the cross tube (3) so as to protrude therefrom; c) the rear legs (2,2 '), offset to the front legs (1, 1') inwards, are attached to the cross tube (3); and d) the seat plate (4) is arranged on the cross tube (3) between the back parts (10, 10 ') of the front legs (1, 1') projecting over the cross tube (3).

4. Chair according to one of claims 1 to 3, characterized in that a) the legs (1, 1 '; 2.2 ") consist of tubular material and are welded to the cross tube (3); b) the rear legs (2, 2 ') with their upper ends (20, 20') in the cross tube (3) and thereby an insertion opening (200, 200 ') for a cover cap

(38,38 ') or an armrest (8,8 ") arises; and c) the seat plate (4) is arranged either rigidly or foldable over the cross tube (3).

5. Chair according to one of claims 1 to 4, characterized in that a) the legs (1, 1 '; 2.2 ") consist of tube material and are welded to the cross tube (3); b) the seat plate (4) is arranged above the cross tube (3) either rigidly or by means of a pivot bearing (7), and c) at least one console (6) carrying the seat plate (4) can be placed on the cross tube (3).

6. Chair according to one of claims 1 to 5, characterized in that a) on the underside of the seat plate (4) on the one hand the main axis (D) an open pocket (40) and on the other hand the main axis (D) a fastening web (41) is provided are; b) the console (6) has a plug end (60) on one end face and, opposite this, a shaft end (61); and c) in the assembled state, the plug end (60) is pushed into the pocket (40) and the shaft end (61) is connected to the fastening web (41); wherein d) at least for the chair version with a foldable seat plate (4) the console (6) for receiving a pivot bearing (7) has bearing tongues (62).

7. Chair according to one of claims 1 to 6, characterized in that a) the roller-shaped rotary bearing (7) on the main axis (D) is fixedly inserted into a jacket recess (31) in the cross tube (3); b) the two side surfaces (70) of the rotary bearing (7) are penetrated by the main axis (D); c) there are stop shoulders (71, 72) on the side surfaces (70); d) the bearing tongues (62), comprising both side surfaces (70), are rotatably fixed on the main axis (D); e) one of the flanks (620, 621) of a bearing tongue (62) in the folded use position or in the folded rest position of the seat plate (4) bounces against the stop shoulders (71, 72), which indicates the end positions of the foldable

Seat plate (4) defined.

8. Chair according to one of claims 1 to 7, characterized in that each armrest (8,8 ') consists of: a) a support (80), the plug end (800) below for insertion into the insertion openings (200,200') is determined, which are present on the rear legs (2,2 ') and as an opening in the cross tube (3); b) a support (81) attached to the top of the support (80); and c) an armrest (82) held by the carrier (81); wherein d) from the carrier (81) in the armrest (82) a swivel mechanism (83) with the

Axis of rotation (D1) engages; e) the swivel mechanism (83) allows the armrest (82) of the

Use position to pivot outward about the axis of rotation (D1) into the rest position, where the armrest (82) is pivoted out so far that it when stacked one on top of the other, the next higher chair is not hindered; and f) the swivel mechanism (83) has a spring arranged around the axis of rotation (D1)

(830), against whose force the armrest (82) from a lock

(831) can be swung out in the use position, and this locking means (831) can also act in the rest position of the armrest (82); and g) the lock (831) e.g. comprising a nose (820) projecting on the underside of the armrest (82) and a complementary contour (810) present on the top of the carrier (81).

9. Chair according to one of claims 1 to 8, characterized in that at least on one of the armrests (8,8 ") a side shelf (9) is mounted, which by means of a tilt-swivel mechanism (90) from the vertically hanging rest position in the horizontal use position in front of the body of the seated user is pivotable.

10. Chair according to claim 9, characterized in that a) the tilt-pivot mechanism (90) consists of a horizontal joint (91) and an angled vertical joint (92); b) the horizontal joint (91) is composed of a base sleeve (910) with a stop cam (911) and a sleeve piece (912) eccentrically arranged below the side shelf (9) with a recess (913); c) the sleeve piece (912) with its recess (913) sits on the base sleeve (910) and the stop cam (911) with the horizontal pivoting of the

Side shelves (9) within the recess (913) moves; and d) locking elements (914, 914 ') are provided on the base sleeve (910) and the sleeve piece (912) for locking the position of use of the side shelf (9).

11. Chair according to claim 10, characterized in that a) the vertical joint (92) of the tilt-swivel mechanism (90) consists of a receiving sleeve (920) and an inserted into the receiving sleeve (920) insertion pin (922) which is against a spring (924) limited extension is cash; b) the receiving sleeve (920) attaches to the upper end of the support (80) of an armrest (8, 8 '); c) the plug-in pin (922) is angled at the base sleeve (910) of the horizontal joint (91); and d) a wedge cam (921) is arranged on the receiving sleeve (920) and a wedge-shaped complementary cam (923) is arranged on the insertion pin (922); e) wedge cams (921) and complementary cams (923) interact as overload protection; and f) in the event of overloading, the insertion pin (922) partially moves away from the receiving sleeve (920) against the resistance of the spring (924), so that the complementary cam (923) jumps over the wedge cam (921) and the side shelf (9) into the vertical hanging resting position falls.

12. Chair according to one of claims 1 to 11, characterized in that on the cross tube (3) on both the main axis (D) penetrating outer sides, mutually complementary coupling elements (39, 39 ') are fixedly arranged, which have an undercut pin as suspension contours ( 390) or an undercut engagement (390 ') accessible from above for hanging the pin (390).

13. Chair according to claim 1 or 2, characterized in that a) the bridge pieces (500,500 ') in the visible area, ie as separate components between their upper and lower plug ends (501.501'; 502.502 ") or in one piece with the backrest part ( 51) underneath which a rib structure (503) down to the lower plug ends (502,502 '); b) the rib structure (503) is created by numerous radially circumferential grooves at systematic intervals; and c) to optimize the bending characteristics of the bridge pieces (500,500') and thus the depth of the grooves of the entire backrest (5), from groove to groove upwards to the backrest part (51) and possibly also to the lower plug ends (502, 502 '), is successively reduced.

14. Chair according to claim 13, characterized in that a) the cross sections of the bridge pieces (500,500 '), the legs (1, 1'; 2,2 ') and the connecting part on the backrest part (51), in the region of the side struts (50th , 50 '), are designed essentially the same, which results in harmonious transitions from the ends (100, 100') of the front legs (1, 1 ') to the bridge sections (500, 500') and from here to the backrest part (51); and b) for example the cross-section are coincidentally oval.