EP2908696B2 - Synchronous seat adjustment - Google Patents

Description

Field of application of the invention

The present invention relates to a chair with mutually synchronous adjustment between the backrest and seat inclination from a zero position with the backrest, in principle, standing vertically up to a maximum inclination. The chair has a floor-standing frame to which a base is rigidly attached. A seat support is connected to the base and has a seat area and a back area. The chair also has two backrest brackets that can be deflected differently from one another and are attached to the base on the one hand and to the back area of the seat support on the other. The seat support is covered with a cover. When equipped as an office swivel chair, a height-adjustable gas spring is arranged in the subframe, on which the base rests, in order to adjust the seat support to a height corresponding to the needs of a user and to make it rotatable about a vertical axis.

State of the art

From the patent publications JP 10 151 033 A and U.S. 5,713,632 chair constructions are known with a seat surface that is divided into two perpendicularly to the front of the chair, in order to allow the seat surface to be deflected with a lateral inclination.

In the EP 1 401 306 B1 discloses a chair having a seat and a backrest, each consisting of a number of mutually independently moveable, modularly joined elements. The division of the elements runs parallel to the front of the chair, and depending on the user's weight shift, the individual elements are deflected with varying degrees of lateral inclination.

subject of WO 2007/110729 A2 is a chair whose backrest has two elastic side rails with a ribbed structure. If the backrest is loaded asymmetrically, the side rails are deflected differently.

The chair according to EP 1 946 676 B1 allows a mutually synchronous adjustment between back tilt and seat tilt, over a range between a respective zero position of back tilt and seat tilt and a respective maximum back tilt and seat tilt. A base is rigidly fastened to the underframe designed to be placed on the floor. A seat support is connected to the base and has a seat area and a back area. Two backrest brackets, which can be deflected differently from one another, are fastened on the one hand to the base and on the other hand to the back area of the seat support, so that a cushioned lateral inclination of the seat is made possible.

object of the invention

Based on the conditions of a mutually synchronous adjustment between back and seat inclination on a chair and also an asymmetrical lateral deflection, the invention is based on the object of proposing a perfected construction for series production and for the ergonomically optimal functional properties of the chair. Significant aspects are the most efficient use of materials, productive assembly in series production, ease of service with minimal maintenance and the possibility of an aesthetic design of the chair.

Overview of the invention

The chair is of the type with mutually synchronous adjustment between back inclination and seat inclination, namely over a range between a respective zero position of back inclination and seat inclination and a respective maximum back inclination and seat inclination. The chair has a floor-standing frame to which a base is rigidly attached. A seat support is connected to the base and has a seat area and a back area. The chair also has two backrest brackets that can be deflected differently from one another and are attached to the base on the one hand and to the back area of the seat support on the other. The two backrest brackets are articulated independently of one another on a fixed first axis of rotation on the base. The seat area of the seat support is articulated on a fixed second axis of rotation on the base. The two backrest brackets are articulated independently of one another on an elastically deformable third axis of rotation on the back area of the seat support. The back area of the seat carrier can be twisted elastically.

Specific embodiments of the invention are defined below: A first spring unit is provided on the chair, which acts against the respective movable backrest bracket. A second spring unit is connected in parallel to the first spring unit, which is supported on the one hand on the base in a fixed abutment and on the other hand acts against the respective movable backrest bracket.

The first spring unit is adjustable and includes two separate first spring elements. The second spring unit includes two separate second spring elements. The base is a U-shaped housing having a central portion and two arms extending therefrom. A second spring element is arranged in each of the legs. The first axis of rotation runs through the central part, while the second axis of rotation extends through the free ends of the two legs.

The seat support includes two bars that extend across the seat area and the back area. On the two spars are upper connecting organs in the back area present, through which the third axis of rotation runs. In the seat area, there are central connecting elements on the two bars, through which a fourth axis of rotation runs. A first transverse strut is arranged between the two bars in the seating area, on which there are front connecting elements through which the second axis of rotation runs.

The first cross brace is arranged at the front of the seat area, and a second cross brace extends between the two bars at the back of the seat area. The back area is bridged between the two bars by a back bar. The two struts, the two cross braces and the back bar form the seat support as assembled individual parts, or the seat support is produced in one piece as a plastic injection molded part. Each rail has an area of elasticity between the seat area and the back area.

The chair can be equipped with armrests, each armrest being articulated on the one hand on the third axis of rotation and on the other hand on the fourth axis of rotation. Each armrest has a support area extending essentially horizontally from the third axis of rotation and a support area extending upwards from the fourth axis of rotation. There is a transition between the contact area and the support area. The armrests support the damping effect of the first spring unit and the second spring unit when the chair is moved to the maximum back inclination and seat inclination. When the chair moves back towards the zero position of the back and seat inclination, the armrests support the restoring force of the two spring units. The armrests are made in one piece as a plastic injection molding.

A fixed fifth axis of rotation extends through the base, on which a presetter for adjusting the intensity of the first spring unit is arranged. The individual first spring element is a block-shaped body made of elastomer, which is arranged at the base of each backrest bracket. Two displaceable pressure pieces are arranged on the presetter along the fifth axis of rotation, of which one of the pressure pieces is assigned to one of the first spring elements. The pressure pieces can be aligned with the first two spring elements by operating the presetter with a selectable degree of congruence in order to move the chair to the maximum back and seat inclination according to the portions of the first spring elements squeezed between the attachments and the pressure pieces together with the effect of the second Spring unit to achieve the desired damping.

The second spring elements of the second spring unit are helical compression springs. Every second spring element is provided with an end piece which has a fixing member which receives one end of the spring element and thus creates a spring assembly. A sixth axis of rotation extends through the approaches of both backrest brackets, on which the end pieces of both spring assemblies are articulated.

The bars of the seat support have a longitudinal groove in which a cover to cover the seat support can be fixed.

A height-adjustable gas spring is arranged in the underframe, on which the base rests, in order to adjust the seat support to a height corresponding to the needs of a user and to make it rotatable about a vertical axis.

Brief description of the attached drawings

• Figur 1A - einen erfindungsgemässen Stuhl, in perspektivischer Frontansicht;
• Figur 1B - den Stuhl gemäss Figur 1A, ohne Bezug, in gewechselter perspektivischer Frontansicht;
• Figur 1C - den Aufbau gemäss Figur 1B, in perspektivischer Rückansicht;
• Figur 1D - den Aufbau gemäss Figur 1B, in perspektivischer Unteransicht;
• Figur 1E - den Aufbau gemäss Figur 1B mit dem Träger in Nullposition von Rücken- und Sitzneigung, in Seitenansicht;
• Figur 1F - den Aufbau gemäss Figur 1B mit dem Träger in maximaler Rücken- und Sitzneigung, in Seitenansicht;
• Figur 2A - den Aufbau gemäss Figur 1B, in teilweiser perspektivischer Explosivansicht, von vorne oben;
• Figur 2B - den Aufbau gemäss Figur 2A, in teilweiser perspektivischer Explosivansicht, von hinten unten;
• Figur 3A - die Basis, die Federeinheiten und die Lehnenbügel aus Figur 2A, in perspektivischer Explosivansicht;
• Figur 3B - den Aufbau gemäss Figur 3A, in gewechselter perspektivischer Explosivansicht;
• Figur 3C - das vergrösserte Detail X1 aus Figur 3A;
• Figur 3D - den Schieber aus Figur 3A, in vergrösserter Perspektivansicht;
• Figur 3E - die Abdeckung aus Figur 3A, in vergrösserter Perspektivansicht;
• Figur 4A - das Gehäuse der Basis aus Figur 3A, in vergrösserter perspektivischer Rückansicht;
• Figur 4B - das Gehäuse gemäss Figur 4A, in partieller perspektivischer Schnittansicht;
• Figur 4C - ein partiell zusammengesetztes Paket der zweiten Federeinheit aus Figur 3A, in vergrösserter Perspektivansicht;
• Figuren 4D bis 5L: den phasenweisen Zusammenbau von Basis, Federeinheiten und Lehnenbügeln, in Perspektivansichten;
• Figur 4D - erste Phase: das Gehäuse gemäss Figur 4A, mit eingesetzter zweiter Federeinheit;
• Figur 4E - den Aufbau gemäss Figur 4D, in partieller perspektivischer Schnittansicht;
• Figur 4F - zweite Phase: den Aufbau gemäss Figur 4E, ergänzt mit eingesetzten Druckstücken;
• Figur 4G - den Aufbau gemäss Figur 4F, in partieller perspektivischer Schnittansicht;
• Figur 4H - dritte Phase: den Aufbau gemäss Figur 4F, mit dem Gehäuse angenähertem Voreinsteller;
• Figur 4J - den Aufbau gemäss Figur 4H, mit im Gehäuse steckendem Voreinsteller;
• Figur 4K - den Aufbau gemäss Figur 4J, in partieller perspektivischer Schnittansicht;
• Figur 5A - vierte Phase: den Aufbau gemäss Figur 4K, mit am Gehäuse positioniertem Schieber und Abdeckung sowie mit dem Gehäuse angenäherten Lehnenbügeln;
• Figur 5B - fünfte Phase: den Aufbau gemäss Figur 5A, mit zwischen Gehäuse und Lehnenbügeln eingefügter erster Federeinheit;
• Figur 5C - sechste Phase: den Aufbau gemäss Figur 5B, mit an den Lehnenbügeln fixierter erster Federeinheit und in die unteren Achslöcher eingesetzten Buchsen;
• Figur 5D - siebente Phase: den Aufbau gemäss Figur 5C, mit den abgesenkten Lehnenbügeln auf der Drehachse D1 ausgerichtet und auf der Drehachse D6 an der zweiten Federeinheit angedockt, in partieller perspektivischer Schnittansicht;
• Figur 5E - den Aufbau gemäss Figur 5D, mit aufgerichteten Lehnenbügeln, in partieller perspektivischer Schnittansicht;
• Figur 5F - achte Phase: den Aufbau gemäss Figur 5E, mit auf der Drehachse D1 ausgerichteten und dem Gehäuse angenäherten Hülsen;
• Figur 5G - den Aufbau gemäss Figur 5F, mit eingesetzten Hülsen;
• Figur 5H - neunte Phase: den Aufbau gemäss Figur 5G, mit auf der Drehachse D1 ausgerichtetem und dem Gehäuse angenähertem Höheneinsteller, Auslöser und Kappe;
• Figur 5J - den Aufbau gemäss Figur 5H, mit auf der Drehachse D1 eingesetztem Höheneinsteller und montiertem Auslöser;
• Figur 5K - den Aufbau gemäss Figur 5J, mit auf der Drehachse D1 eingesetzter Sicherung;
• Figur 5L - zehnte Phase: den Aufbau gemäss Figur 5K, mit aufgesteckter Kappe;
• Figuren 6A bis 8: Einstellungen der Vorspannung an erster Federeinheit, bei Nullposition von Rücken- und Sitzneigung bzw. maximaler Rücken- und Sitzneigung, in partieller perspektivischer Schnittansicht, als Prinzipdarstellungen;
• Figur 6A - den Aufbau gemäss Figur 5K, bei Nullposition von Rücken- und Sitzneigung und minimaler Vorspannung an erster Federeinheit;
• Figur 6B - den Aufbau gemäss Figur 6A, in erweiterter Schnittansicht auf die erste Federeinheit;
• Figur 7A - den Aufbau gemäss Figur 5K, bei Nullposition von Rücken- und Sitzneigung und maximaler Vorspannung an erster Federeinheit;
• Figur 7B - den Aufbau gemäss Figur 7A, in erweiterter Schnittansicht auf die erste Federeinheit;
• Figur 7C - den Aufbau gemäss Figur 7A, in erweiterter Schnittansicht auf die zweite Federeinheit;
• Figur 8 - den Aufbau gemäss Figur 5K, bei maximaler Rücken- und Sitzneigung und minimaler Vorspannung an erster Federeinheit, in erweiterter Schnittansicht auf die erste Federeinheit;
• Figuren 9A bis 9D: unblockierte bzw. blockierte Nullposition von Rücken- und Sitzneigung, als Prinzipdarstellungen;
• Figur 9A - den Aufbau gemäss Figur 5L, Schieber in unblockierter Stellung;
• Figur 9B - den Aufbau gemäss Figur 5L, Schieber in blockierter Stellung;
• Figur 9C - das vergrösserte Detail X2 aus Figur 9A; und
• Figur 9D - das vergrösserte Detail X3 aus Figur 9B.

Show it:

• Figure 1A - A chair according to the invention, in perspective front view;
• Figure 1B - according to the chair Figure 1A , without cover, in an alternate perspective front view;
• Figure 1C - according to the structure Figure 1B , in perspective rear view;
• Figure 1D - according to the structure Figure 1B , in a perspective view from below;
• Figure 1E - according to the structure Figure 1B with the carrier in the zero position of back and seat inclination, in side view;
• Figure 1F - according to the structure Figure 1B with the wearer in maximum back and seat inclination, in side view;
• Figure 2A - according to the structure Figure 1B , in partially exploded perspective view, front and top;
• Figure 2B - according to the structure Figure 2A , in partially exploded perspective view, from the rear below;
• Figure 3A - the base, the spring units and the backrest brackets Figure 2A , in exploded perspective view;
• Figure 3B - according to the structure Figure 3A , in alternate perspective exploded view;
• Figure 3C - the enlarged detail X1 off Figure 3A ;
• Figure 3D - the slider off Figure 3A , in enlarged perspective view;
• Figure 3E - the cover off Figure 3A , in enlarged perspective view;
• Figure 4A - the body of the base Figure 3A , in enlarged perspective rear view;
• Figure 4B - the housing according to Figure 4A , in partial perspective sectional view;
• Figure 4C - A partially assembled package of the second spring unit Figure 3A , in enlarged perspective view;
• Figures 4D to 5L : the phased assembly of the base, spring units and backrest brackets, in perspective views;
• Figure 4D - first phase : the case as per Figure 4A , with inserted second spring unit;
• Figure 4E - according to the structure Figure 4D , in partial perspective sectional view;
• Figure 4F - second phase: the structure according to Figure 4E , supplemented with pressure pads;
• Figure 4G - according to the structure Figure 4F , in partial perspective sectional view;
• Figure 4H - third phase: the structure according to Figure 4F , with the preset closer to the housing;
• Figure 4J - according to the structure Figure 4H , with presetter plugged into the housing;
• Figure 4K - according to the structure Figure 4J , in partial perspective sectional view;
• Figure 5A - fourth phase : the structure according to Figure 4K , with the slider and cover positioned on the body and with the backrest brackets brought closer to the body;
• Figure 5B - fifth phase: the structure according to Figure 5A , with the first spring unit inserted between the housing and the backrest brackets;
• Figure 5C - sixth phase : the structure according to Figure 5B , with the first spring unit fixed to the backrest brackets and bushings inserted into the lower axle holes;
• Figure 5D - seventh phase: the structure according to Figure 5C , with the lowered backrest brackets aligned on the axis of rotation D1 and docked on the axis of rotation D6 on the second spring unit, in a partial perspective sectional view;
• Figure 5E - according to the structure Figure 5D , with erected backrest brackets, in a partial perspective sectional view;
• Figure 5F - Eighth phase: the structure according to Figure 5E , with sleeves aligned on the axis of rotation D1 and brought closer to the case;
• Figure 5G - according to the structure Figure 5F , with inserted sleeves;
• Figure 5H - ninth phase : the structure according to Figure 5G , with the height adjuster, trigger and cap aligned on the axis of rotation D1 and closer to the body;
• Figure 5J - according to the structure Figure 5H , with height adjuster inserted on pivot D1 and trigger mounted;
• Figure 5K - according to the structure Figure 5J , with fuse inserted on pivot D1;
• Figure 5L - tenth phase: the structure according to Figure 5K , with attached cap;
• Figures 6A to 8 : Adjustments of the preload on the first spring unit, at zero position of back and seat inclination or maximum back and seat inclination, in a partial perspective sectional view, as a schematic representation;
• Figure 6A - according to the structure Figure 5K , with the back and seat inclination in zero position and minimum preload on the first spring unit;
• Figure 6B - according to the structure Figure 6A , in an expanded sectional view of the first spring unit;
• Figure 7A - according to the structure Figure 5K , with back and seat inclination in zero position and maximum preload on the first spring unit;
• Figure 7B - according to the structure Figure 7A , in an expanded sectional view of the first spring unit;
• Figure 7C - according to the structure Figure 7A , in an expanded sectional view of the second spring unit;
• figure 8 - according to the structure Figure 5K , with maximum back and seat inclination and minimum preload on the first spring unit, in an expanded sectional view of the first spring unit;
• Figures 9A to 9D : unblocked or blocked zero position of back and seat inclination, as schematic representations;
• Figure 9A - according to the structure Figure 5L , spool in unblocked position;
• Figure 9B - according to the structure Figure 5L , spool in blocked position;
• Figure 9C - the increased detail X2 off Figure 9A ; and
• Figure 9D - the increased detail X3 off Figure 9B .

example

A detailed description of an exemplary embodiment of the chair according to the invention is given below with reference to the attached drawings.

The following definition applies to the entire further description. If reference numerals are contained in a figure for the purpose of clarity in the drawing, but are not explained in the directly associated descriptive text, reference is made to their mention in the preceding figure descriptions. In the interest of clarity, the repeated designation of components in the following figures is mostly dispensed with if it is clearly recognizable from the drawing that they are “recurring” components.

Figures 1A to 1F

The chair consists of the base 1 placed on the floor with the fork-shaped base 2 resting on it. Two backrest brackets 3 spaced apart from one another extend upwards from the base 2 , on each of which a support 6 and an armrest 7 is fastened. The subframe 1 has a star-shaped base 10, from which a vertical standpipe 11 extends centrally, which serves to accommodate a vertical gas spring 12 . The foot 10 is provided with several floor elements 14, eg rollers. A fixed first axis of rotation D1 runs through the rear region of the base 2 , on which the backrest brackets 3 are articulated and on which a height adjuster 25 is guided in an axially movable manner. The gas spring 12 can be actuated with the height adjuster 25 and thus the height of the seat can be varied according to the needs of a user. At the same time , the gas spring 12 allows the seat to be rotated about a vertical axis V , as is customary for comfortable office chairs.

A fixed second axis of rotation D2 runs through the front region of the base 2 and parallel to the first axis of rotation D1 , on which the carrier 6 , which is made in one or more parts, is articulated at the front. The back of the carrier 6 is also on the moveable third axis of rotation D3 connected to the two backrest brackets 3 . This third axis of rotation D3 can be pivoted about the first axis of rotation D1 and extends through the back area 62 of the carrier 6. The rotatable presetter 24 is arranged on the fixed fifth axis of rotation D5 , with which the deflection of the back and seat inclination from the zero position R ₀ ,S ₀ required force can vary. A fixed axis A runs parallel at a distance from the axes of rotation D1, D2, D3 and serves to accommodate the second spring unit 5 (see Fig. Figure 3A ).

The chair is preferably equipped with two armrests 7 , which are articulated on the one hand in the third axis of rotation D3 and on the other hand in a movable fourth axis of rotation D4 , which extends through the seat area 61 of the carrier 6 and can also be pivoted about the first axis of rotation D1 . The individual, quasi-angular armrest 7 is structured into the support area 71, which protrudes upwards from the fourth axis of rotation D4 , and the supporting area 72, which is basically horizontal, and which leads to the third axis of rotation D3 . There is an arcuate transition 78 between the support area 71 and the support area 72 .

The carrier 6 consists essentially of two strip-shaped, parallel, spaced apart and in principle L-shaped bent bars 60 , between which a first cross brace 63, a second cross brace 67 and a back bracket 64 extend, which connect the bars 60 to one another. The entire carrier 6 can be made in one piece or the cross braces 63, 67 and the back bracket 64 are inserted between the bars 60 as separate parts. The first cross brace 63 runs at the front and the second cross brace 67 at the rear of the seat area 61 , while the back bracket 64 extends over the back area 62 . The transition between the seat area 61 and the back area 62 is designed as an area of elasticity 68 . Each bar 60 has a groove 66 on its side pointing outwards, in which a cover 69 is fixed, which spans the entire carrier 6 on the front, so that a quasi-horizontal seat and a quasi-vertical backrest is created for the user.

• minimale Rückenneigung R₀ , d.h. der Rückenbereich 62 des Trägers 6 steht annähernd vertikal;
• minimale Sitzneigung S₀ , d.h. der Sitzbereich 61 des Trägers 6 ist annähernd horizontal;
• die Elastizitätsbereiche 68 des Trägers 6 sind nicht aufgebogen; und
• die Armlehnen 7 sind nicht aufgebogen.

The zero position of the back and seat inclination (s. Figure 1E ) is characterized as follows:

• minimum back inclination R ₀ , ie the back area 62 of the wearer 6 is approximately vertical;
• minimum seat inclination S ₀ , ie the seat area 61 of the carrier 6 is approximately horizontal;
• the areas of elasticity 68 of the carrier 6 are not bent up; and
• the armrests 7 are not bent up.

• maximale Rückenneigung R_max , d.h. der Rückenbereich 62 des Trägers 6 steht schräg nach hinten;
• maximale Sitzneigung S_max , d.h. der Sitzbereich 61 des Trägers 6 steht schräg nach hinten unten;
• die Elastizitätsbereiche 68 des Trägers 6 sind maximal aufgebogen; und
• die Armlehnen 7 sind maximal aufgebogen, z.B. an den Stützbereichen 71 und/oder den Übergängen 78, je nach Konfiguration der Armlehnen 7.

The maximum back and seat inclination (s. Figure 1F ), which are synchronous to each other, is characterized as follows:

• maximum back inclination R _max , ie the back area 62 of the wearer 6 is inclined backwards;
• maximum seat inclination S _max , ie the seat area 61 of the carrier 6 is inclined backwards and downwards;
• the areas of elasticity 68 of the carrier 6 are maximally bent; and
• the armrests 7 are bent up to the maximum, e.g. at the support areas 71 and/or the transitions 78, depending on the configuration of the armrests 7.

Figures 2A and 2B

The first transverse strut 63 has connecting elements at its free ends in order to connect them to the receptacle present on the respective strut 60 . From the first transverse strut 63, two front connecting elements 630 , spaced apart from each other, each have a front axle hole 633 , through which the second axis of rotation D2 runs. Adjacent to the area of elasticity 68, between the bars 60, adjacent to the seat area 61, the second cross brace 67 is present. The free ends of the second transverse strut 67 have connecting elements which are used to connect to the receptacle on the associated strut 60 .

Between the second cross strut 67 and the first cross strut 63 there is a central connection element 610 on each spar 60 which has a fifth axle hole 615 . Between the area of elasticity 68 and adjacent to the back area 62, each rail 60 has an upper connecting element 620 with a fourth axle hole 624. The back bracket 64 extends between the rails 60 near the lower end of the back area 62. The back bracket 64 has on both sides at the outer ends a connector 640, which are designed to be complementary to the upper connection element 620 located on the respective spar 60 . The two cross braces 63, 67 and the back bracket 64 are fixed to the respective rail 60 , for example by means of screws.

At the free end of the support area 72, the individual armrest 7 has an upper pivot pin 74 which extends on the third axis of rotation D3 . At the free end of the support area 71 sits a lower axle pin 75 which is directed towards the fourth axis of rotation D4 . The armrests 7 are offset slightly outwards relative to the carrier 6 , with the third axis of rotation D3 running in alignment through the upper axle pins 74 of the armrests 7 and the fourth axle holes 624 of the upper connection elements 620 of the bars 60 . The fourth axis of rotation D4 extends in alignment through the lower pivot pins 75 of the armrests 7 and the fifth pivot holes 615 of the central connecting members 610 of the spars 60. Two pivot pins 224 lie on the second pivot axis D2 and are intended for insertion into the base 2 . By means of the pivot pins 224, the carrier 6 is pivotally connected at its front connecting elements 630 to the base 2 at the level of the second axis of rotation D2 . The stand 1 is shown removed from the base 2 here.

Preferably, the seat areas 61 and the are on the carrier 6 outside the areas of elasticity 68 Back areas 62 elastic. The first and second cross braces 63, 67 and the back bracket 64 can also be elastic. Furthermore, outside of the transitions 78 on the armrests 7— instead of the transitions 78 or in addition to them—the support areas 71 and the contact areas 72 can also be elastic. The carrier 6 is particularly advantageous as a one-piece plastic injection molded part and the cover 69 as a one-piece fabric that can be shrunk onto the carrier 6 .

Figures 3A to 3E

The base 2 consists of a housing 20, the presetter 24 and the height adjuster 25 together. The housing 20 has a central part 21, from which two mutually spaced, parallel legs 22 depart. The first axis of rotation D1 , the fifth axis of rotation D5 and the axis A extend through the central part 21. The second axis of rotation D2 runs close to the free ends of the legs 22, with a pivot pin 224 each being aligned on the second axis of rotation D2 and ready for insertion.

A height-adjustable slide 26 for blocking the zero position of the back and seat inclination R ₀ , S ₀ or for releasing it for the deflection into the maximum back and seat inclination R _max , S _max is provided at the rear end of the central part 21 . The slide 26 has a plate 260 on which two webs 261 run which are spaced apart vertically parallel to one another and which engage in complementary grooves present on the housing 20 , so that the slide 26 is guided in the upward and downward movement. Extending laterally from the plate 260 at the upper edge is a cantilever 262 on which a cuboid block 263 is seated. The block 263 serves to block the back or seat inclination, which will be described later. Opposite the top edge of slider 26 is a ledge 264 on its bottom edge to provide ergonomic access for the user. Opposite the webs 261, the plate 260 has elevations which are intended for complementary engagement in existing contours on the cover 27 . The slider 26 is fixed to the housing 20 by means of the cover 27 and a screw 270 , but the upward and downward movement of the slider 26 is ensured.

A cap 28 is provided to close the third cavity 213 (see Fig . Figure 4A ) intended. The pre-adjuster 24 lying on the fifth axis of rotation D5 consists of a spindle 240 with an external thread 241. A handle 243 can be positioned at one end of the spindle 240 , with a safety device 242 being able to be plugged onto the opposite end of the spindle 240 . Two quasi-rectangular pressure pieces 23 lie in the direction of alignment with the fifth axis of rotation D5 and are intended for complementary engagement with the external thread 241 of the spindle 240 . The height adjuster 25 lying on the first axis of rotation D1 has a rod 250 on which two sleeves 251, four bushings 252, a trigger 253, a fuse 254, a spring 255 and a handle 256 can be positioned.

The backrest brackets 3 are mirror-symmetrical, so that only one backrest bracket 3 is to be described below. The backrest bracket 3 has a projection 30 in which sits a lower axle hole 302 which is aligned with the first axis of rotation D1 . Adjacent to the shoulder 30 is a shoulder 31 which is contoured 310 . The contour 310 is stepped and has a first paragraph 311 and a second paragraph 312 to which the free space 313 is connected. Adjacent the shoulder 31 is a cutout in the form of a bearing 32 for receiving the insert 320 . The bearing 32 or the insert 320 later seated therein is traversed by a sixth axis of rotation D6 , which is parallel and spaced apart from the first axis of rotation D1 . The third axis of rotation D3, which extends through the upper axis hole 324, lies opposite the axes of rotation D1, D6 .

The first spring unit 4 consists of two quasi-trapezoidal first spring elements 40, preferably made of elastically deformable plastic, which can be fixed to the respective shoulder 31 of the corresponding backrest bracket 3 . The second spring unit 5 is composed of two identical packages 50 through which the axis A and the sixth axis of rotation D6 extend. In the direction of alignment of the axis A , each package 50 is assigned the pin 57 which fixes the package 50 in the base 2 . A bolt 55 associated with each package 50 is aligned with the sixth axis of rotation D6 and, in the assembled state, protrudes through the insert 320 seated in the bearing 32 .

Figures 4A to 4C

The central part 21 of the housing 20 has a first cavity 210 adjacent to each leg 22 , which is used to accommodate the corresponding pressure piece 23 . A second cavity 220 for storing the package 50 is present in the longitudinal extension of each leg 22 . The third cavity 213 is provided on the upper side of the central part 21 and is used for inserting the trigger 253 , the fuse 254 and the spring 255 of the height adjuster 25 . The vertical gas spring 12 can be partially inserted and fixed in a receptacle from the underside of the central part 21 , which is more or less aligned with the third cavity 213 .

A total of five first axis holes 211 are present in the housing 20 , all of which are aligned with the fifth axis of rotation D5 . The first axle hole 211 is provided in the outer side wall of the housing 20 only on the side of the presetter 24 . A further first axle hole 211 is located adjacent to this in the partition between the first cavity 210 and the second cavity 220. Between the two first cavities 210 and the third cavity 213, another first axle hole 211 is attached in the corresponding wall. The remaining first axle hole 211 is positioned in the partition wall between the first cavity 210 and the second cavity 220 . There are also a total of four second axis holes 212 in the housing 20 , all of which are aligned with the first axis of rotation D1 . A second axle hole 212 is provided in each of the two outer side walls of the housing 20 . Adjacent to this, between the two first cavities 210 and the third cavity 213 , there is another second axle hole 212 in the corresponding wall. In addition to the first axle holes 211 and second axle holes 212 , there are a total of four holes 217 in the housing 20 , all of which have the axis A cursed. Both outer side walls of the housing 20 are provided with a hole 217 . Adjacent to this sits in the partitions between the first cavity 210 and the second cavity 220 a further hole 217 each. The single leg 22 has at its free end the front fork 222 with a third axle hole 223 therein. The second axis of rotation D2 extends in alignment through the two third axis holes 223.

The packages 50 belonging to the second spring unit 5 have an identical structure, so that only one of them is described below. A second spring element 51 in the form of a spiral spring is connected to an end piece 52 by means of a rear fixing element 53 . The end piece 52 has a slot 54 through which the pin 57 later protrudes. The end piece 52 has a rear fork 56 opposite the rear fixing member 53 , in which the insert 320 is located. When the package 50 is assembled, the bolt 55 protrudes through the two bores in the rear fork 56 and the insert 320 and is secured with the fuse 550 in the axial direction along its sixth axis of rotation D6 . The axis A, on the other hand, runs through the pin 57 and the slot 54 in the end piece 52 in alignment.

Figures 4D and 4E (First construction phase)

The second spring unit 5 is inserted into the base 2 and connected thereto. In this case, the insert 320 is first placed in the rear fork 56 on the corresponding package 50 and secured in the axial direction along the sixth axis of rotation D6 by means of the bolt 55 and the securing device 550 . The respective package 50 is then pushed with the second spring element 51 first into the corresponding second cavity 220 on the leg 22 until the free end of the second spring element 51 is placed on the front fixing element 221 . The pin 57 is inserted in the slot 54 on the axis A and rests in the holes 217. This process takes place in the same way with the other package 50. The pin 57 has a shoulder on one side, which is on the partition wall adjacent to the second cavity 220 in each case lies. The diameter-reduced extension of the pin 57 sits in the complementary hole 217 of the partition. When inserting the pin 57, the corresponding package 50 is lifted slightly.

Figures 4F and 4G (Second phase of construction)

The corresponding pressure piece 23 is inserted into each first cavity 210 . The individual pressure piece 23 rests with a bulge along the internal thread on the upper side of the inner surface of the first cavity 210 , as a result of which the friction during the adjustment process described later is minimized and the adjustment of the pressure pieces 23 becomes smooth. This position of the pressure pieces 23 must be aligned accordingly and fixed until the presetter 24 —shown in the next construction phase—projects through the housing 20 .

Figures 4H to 4K (Third construction phase)

The presetter 24 belonging to the base 2 is inserted inside the housing 20 and its spindle 240 protrudes through the five first axle holes 211 and the two pressure pieces 23. The two pressure pieces 23 are in complementary engagement with the corresponding external threads 241 on the spindle 240. If the Spindle 240 protrudes through all five first axle holes 211 and is in the intended end position, this is provided with the fuse 242 , which is positioned in the second cavity 220 adjacent to the first axle hole 211 . The fuse 242 is seated in a circumferential groove present on the shaft 240 . The handle 243 can be fixed on the spindle 240, for example by means of locking or gluing or a thread.

Figure 5A (Fourth construction phase)

First, the slider 26 and the associated cover 27 are attached to the rear edge of the housing 20, quasi in the direction of alignment with the third cavity 213 . In this case, the cover 27 is fixed with the screw 270 , but allows the slide 26 to move downwards or upwards for the later-described blocking or release of the synchronous adjustment of the back and seat inclination. The two backrest brackets 3 are brought closer to the base 2 , with the bearing 32 on the attachment 30 of the backrest bracket 3 being aligned with the respective insert 320 toward the package 50 .

Figure 5B (Fifth construction phase)

The first spring unit 4 with the first spring element 40 is introduced between the housing 20 and the individual backrest bracket 3 .

Figure 5C (Sixth construction phase)

The first spring elements 40 are fixed to the shoulders 31 , for example glued, and a pair of bushings 252 is inserted into the associated lower axle hole 302 in the shoulder 30 of the backrest bracket 3 .

Figures 5D and 5E (Seventh Construction Phase)

The individual backrest bracket 3 is docked in the lowered position on the corresponding package 50 of the second spring unit 5 (see Fig. Figure 5D ). The bearing 32 on the extension 30 partially encompasses the insert 320 on the package 50, and the first spring element 40 is spaced apart from the first cavity 210 opposite. The two pressure pieces 23 must be positioned via the presetter 24 in such a way that they enable the backrest bracket 3 to be raised as described in the following step. When the backrest bracket 3 is erected, the bearing 32 located on the extension 30 completely encompasses the insert 320 located on the package 50 , and the first spring element 40 lies entirely in the first cavity 210 (see Fig. Figure 5E ).

Figures 5F and 5G (Eighth construction phase)

A sleeve 251 is approached from each side of a leg 22 of the housing 20 to the second axle hole 212 and is aligned with the first axis of rotation D1. The sleeves 251 are inserted into the second axle holes 212 . The individual sleeve 251 protrudes through the second axle hole 212 located in the outer wall of the leg 22 , the bushings 252 inserted in the lower axle hole 302 , the axle hole 212 between the first cavity 210 and the third cavity 213, but does not protrude into the third cavity 213 . but closes flush with it. In this situation, the individual backrest bracket 3 is slightly prestressed, ie the second spring element 51 is slightly compressed, so that the backrest bracket 3 remains in the upright position.

Figures 5H to 5K (Ninth Construction Phase)

The height adjuster 25 approaches the right leg 22 while the preset adjuster 24 protrudes from the left leg 22 . The rod 250 and the handle 256 are aligned with the first axis of rotation D1. The trigger 253, fuse 254, spring 255 and cap 28 are located above the third cavity 213 ready for installation. The rod 250 guided in the sleeves 251 protrudes completely through the sleeve 251, which faces the handle 256 , but only partially through the other sleeve 251 . When the first sleeve 251 is pushed through, the front end of the rod 250 reaches the third cavity 213 and receives the trigger 253 and the spring 255 , which are in the direction of alignment with the first axis of rotation D1 . In the intended end position, the front end of the rod 250 is guided in the second sleeve 251 , which is located on the side of the housing 20 on which the handle 243 is positioned. The handle 256 seated on the spindle 250 is either latched, glued or screwed. By accessing the third cavity 213, the fuse 254 is snapped onto a circumferential groove present on the rod 250 through a slot present on the trigger 253 . The safety device 254 is located inside the trigger 253 and only allows the height adjuster 25 to move axially in the effective range of the spring 255 on the first axis of rotation D1 . The spring 255 is compressed when the height adjuster 25 is actuated and thus causes a restoring force after actuation in order to push the handle 256 into its original position.

Figure 5L (Tenth build-up phase)

Finally , the cap 28 is snapped onto the trigger 253 and thus closes the third cavity 213 .

Figures 6A and 6B

The chair is currently in the zero position with minimal back and seat inclination R ₀ , S ₀ . The second spring unit 5 is under the assembly according to the preload, in which the pins 57 strike in the elongated holes 54 in the direction of the chair front and thus limit the zero position on the chair. The minimum preload on the first spring unit 4 is currently set. In this case, both pressure pieces 23 are positioned using the presetter 24 in such a way that the least amount of overlap with the respective first spring element 40 occurs. When moving to the maximum back and seat inclination R _max , S _max , the first spring elements 40 seated on the shoulders 31 of the projections 30 are pressed against the pressure pieces 23 with the lowest spring resistance due to the increasing inclination of the backrest bracket 3 . This setting is suitable for lightweight users.

Figures 7A to 7C

The chair is still in the zero position with minimal back and seat inclination R ₀ , S ₀ . In contrast to the previous pair of figures 6A and 6B, maximum prestressing is now set on the first spring unit 4 . Both pressure pieces 23 are now positioned with the greatest overlap with respect to the first spring element 40 by actuating the presetter 24 . When moving into the maximum back and seat inclination R _max , S _max , the first spring elements 40 are pressed against the pressure pieces 23 with the greatest spring resistance due to the increasing inclination of the backrest bracket 3 . This setting is suitable for heavier users.

figure 8

The chair is in the maximum back and seat inclination R _max , S _max . The second spring unit 5 is under increased tension, at which the pins 57 strike in the elongated holes 54 in the direction of the back of the chair and thus limit the maximum back and seat inclination R _max , S _max on the chair. The squeezing of the second spring unit 5 occurs through the engagement of the bearings 32 in the rear forks 56 of the respective packet 50 on the sixth axis of rotation D6, which is pivotable about the fixed first axis of rotation D1 . The minimum pretension is set on the first spring unit 4 as in the pair of figures 6A and 6B, ie both pressure pieces 23 are positioned with the smallest overlap with the respective first spring element 40 . The back area 62 of the carrier 6 is moved backwards and thus also causes the first spring elements 40 to be largely pressed against the pressure pieces 23 , albeit with minimal overlap. As a result, the previously lowest spring resistance has increased somewhat and contributes somewhat to the restoring force in the zero position. The armrests 7 also contribute to cushioning against the maximum back and seat inclination R _max , S _max and as a restoring force in the zero position, which are now widened, in particular as a result of the displacement of the third axis of rotation D3 , e.g. by bending up along the support areas 71 and/or at the transitions 78.

If the chair is equipped without armrests 7 , the spring forces of the first spring unit 4 and/or the second spring unit 5 must be dimensioned to be adequately higher.

Figures 9A and 9C

In the unblocked position, the slide 26 is almost flush with the lower edge of the central part 20 with its strip 264 and is retracted. The block 263 comes to rest above the second step 312 of the contour 310 of the backrest bracket 3 . Because of the shoulder 312, a free space 313 remains between the contour 310 and the block 263. If the backrest bracket 3 is deflected, the block 263 moves into the free space 313 , so that the movement towards the maximum back and seat inclination R _max , S _max allowed on the chair.

Figures 9B and 9D

In the blocked position, the slide 26 protrudes with its strip 264 over the lower edge of the central part 20 and is thus extended. The block 263 now sits below the second paragraph 312 of the contour 310 of the backrest bracket 3 and rests against the contour 310 . There is thus no longer any free space 313 between the contour 310 and the block 263 . The backrest bar 3 is thus locked in the zero position with the minimum back and seat inclination R ₀ , S ₀ .

The equivalent and independently divided effectiveness of the first spring unit 4 and the second spring unit 5 on both sides of the chair, as well as the mutually independent effectiveness of the elasticities on the carrier 6 and on the armrests 7, results in improved comfort in that the right and left shoulder areas of the backrest each according to weight distribution by the user sitting in the chair, is elastically deformed to different extents.

Claims (10)

1. Chair with relative synchronous adjustment between back inclination (R) and seat inclination (S), over a range between a respective zero position of back inclination (R₀ ) and seat inclination (S₀ ) and a respective maximum back inclination (R_max ) and seat inclination (S_max ), comprising:

   a) an underframe (1) intended to be placed on the floor;

   b) a base (2), which is rigidly fastened on the underframe (1);

   c) a seat support (6) connected to the base (2), which comprises a seat region (61) and a back region (62);

   d) two backrest brackets (3), which are deflectable differently from each other and fastened on one side to the base (2) and on the other side to the back region (62) of the seat support (6),

   e) the seat region (61) of the seat support (6) is articulated on the base (2) on a stationary second axis of rotation (D2);

   f) the back region (62) of the seat support (6) is elastically twistable,
   characterised in that

   g) the two backrest brackets (3) are coupled independently of each other to the base (2) on a stationary first axis of rotation (D1);

   h) the two backrest brackets (3) are articulated independently of each other to the back region (62) of the seat support (6) on an elastically deformable third axis of rotation (D3); and

   i) the seat support (6) comprises two bars (60), which extend over the seat region (61) and the back region (62); wherein

   j) upper connecting members (620) through which the third axis of rotation (D3) passes are provided on the two bars (60) in the back region (62);

   k) middle connecting members (610) through which a fourth axis of rotation (D4) passes are provided on the two bars (60) in the seat region (62);

   l) a first crossmember (63) is arranged between the two bars (60) in the seat region (61), on which front connection members (630) are located, through which the second axis of rotation (D2) passes.
2. Chair according to claim 1, characterised in that

   a) a first spring unit (4) is provided, which acts against the respective movable backrest bracket (3); and

   b) in parallel to the first spring unit (4), a second spring unit (5) is provided, which on one side is supported on the base (2) in a stationary counter bearing (221) and on the other side acts against the respective movable backrest bracket (3).
3. Chair according to one of claims 1 and 2, characterised in that

   a) the first spring unit (4) is adjustable and comprises two separate first spring elements (40);

   b) the second spring element (5) comprises two separate second spring elements (51);

   c) the base (2) is a U-shaped housing (20) comprising a central part (21) and legs (22) extending therefrom in an arm-like manner;

   d) a second spring element (51) is arranged in each of the legs (22); and

   e) the first axis of rotation (D1) passes through the central part (21), while the second axis of rotation (D2) extends through the free ends of the two legs (22).
4. Chair according to claim 1, characterised in that

   a) the first crossmember (63) is arranged at the front in the seat region (61) and a second crossmember (67) extends between the two bars (60) at the rear of the seat region (61);

   b) the back region (62) is bridged between the two bars (60) by a back frame (64);

   c) the two bars (60), the two cross members (63, 67) and the back frame (64) form the seat support (6) as a combined single part or the seat support (6) is produced in one piece as a injection moulding plastic part; and

   d) each bar (60) comprises an elasticity region (68) between the seat region (61) and the back region (62).
5. Chair according to one of claims 1 to 4, characterised in that the chair is provided with armrests (7), each of which armrests (7) is attached on one side to the third axis of rotation (D3) and on the other side to the fourth axis of rotation (D4).
6. Chair according to claim 5, characterised in that

   a) each armrest (7) has a resting region (72) extending in principle horizontally from the third axis of rotation (D3) and a support region (71) extending upwards from the fourth axis of rotation (D4);

   b) there is a transition (78) between the resting region (72) and the support region (71);

   c) the armrests (7), during movement of the chair into the maximum back inclination (R_max ) and seat inclination (S_max ), support the damping action of the first spring unit (4) and of the second spring unit (5), and during movement back towards the zero position of back inclination (R₀ ) and seat inclination (S₀ ) the restoring force supports the two spring units (4, 5); and

   d) the armrests (7) are produced in one piece as injection moulding plastic part.
7. Chair according to one of claims 1 to 6, characterised in that

   a) a stationary fifth axis of rotation (D5) extends through the base (2), on which a pre-setter (24) is arranged for setting the intensity of the first spring unit (4);

   b) the individual first spring element (40) is a block-shaped body made from an elastomer, which is arranged at the projection (30) of each backrest bracket (3);

   c) two displaceable pressure pieces (23) are arranged along the fifth axis of rotation (D5) on the pre-setter (24), of which each one of the pressure parts (23) is associated with one of the first spring elements (40); and

   d) the pressure pieces (23) can be aligned by actuating the pre-setter (24) with a selectable degree of congruence to the two first spring elements (40) in order to achieve the desired damping together with the action of the second spring unit (5) when the chair moves into the maximum back inclination (R_max ) and seat inclination (S_max ) according to the portions of the first spring elements (40) which are squeezed between the projections (30) and the pressure parts (23).
8. Chair according to one of claims 1 to 7, characterised in that

   a) the second spring elements (51) of the second spring unit (5) are helical compression springs;

   b) each second spring element (51) is provided with an end piece (52) comprising a securing member (53), which receives one end of the spring element (51) and thus forms a spring package (50); and

   c) a sixth axis of rotation (D6) extends through the projections (30) of both backrest frames (3), on which the end pieces (52) of the two spring packages (50) are attached.
9. Chair according to one of claims 1 to 8, characterised in that the bars (60) of the seat support (6) have a longitudinal groove (66), in which a cover (69) can be attached to stretch over the seat support (6).
10. Chair according to one of claims 1 to 9, characterised in that a vertically adjustable gas spring (12) is arranged in the underframe (1), on which the base (2) rests, in order to set the seat support (6) at a height corresponding to the needs of a user and in order to create a rotatable vertical axis (V).

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