EP2305073A1 - Chair frame for a seat, seat, method for producing the chair frame, tool for carrying out the method - Google Patents

Abstract

The furniture has a backrest with a leaning part and two armrest bars that extend laterally forward from the leaning part. The armrest bars taper conically inside to a front end and exhibit sleeve-shaped receiving pieces. A tubular chair frame has two end sections (22) for fastening the chair frame to the backrest. Each end section of the chair frame exhibits a conical shaped outline (26). The end sections are arranged and fastened safely in the receiving pieces of the armrest bars in an installed condition. A seat is fastened to the chair frame and/or the backrest. The chair frame is formed from a metallic pipe. The seat and/or the backrest are manufactured from plastic molded parts. Independent claims are also included for the following: (1) a method for manufacturing a chair frame of a seat furniture (2) a tool for manufacturing a chair frame of a seat furniture.

Description

TECHNICAL AREA

The present invention relates to a chair frame for a chair. The present invention further relates to a chair, a method for producing the chair frame and a tool for carrying out the method.

STATE OF THE ART

The present invention is in the field of seating, as they are used in particular for office chairs. Such chairs can z. B. in the form of swivel chairs, four-legged chairs, cantilever chairs or generally be formed as a so-called partner chairs. As a partner chairs seating are referred to, which complement other seating in a room meaningful, for example, visitors chairs in an office that provide seating for visitors next to the desk chair, or arranged in a conference room, identically formed chairs. Especially for reasons of comfort, partner chairs are often used as so-called cantilever chairs. A cantilever is a chair without hind legs, the seat yielding resiliently under the weight of a person sitting on it. In the following, the present invention as well as the problem on which it is based will be explained with reference to a partner chair designed as a cantilever, but without restricting the invention to that effect. Cantilever chairs are well known in many different versions, such. B. in the EP 1 987 738 A1 and the EP 1 665 956 A2 , With them, the seat is supported by a carrying frame without rear legs, so that it can yield and vibrate under load. To accommodate the high bending forces occurring in the support frame, this type of chair usually has a metallic, more or less rigid tube frame.

When mounting the backrests and the seat shell are attached to the support frame of the cantilever. Due to the very high forces that can act on both the seat, as well as on the backrest, a stable connection of the backrest and the seat with the tubular frame must be made sure that especially in heavy load over a lifetime The chair remains intact for a long period of time.

Another requirement is that such a connection between the backrest and tube frame with the least possible installation effort is possible.

In addition, chairs as design objects are subject to requirements in terms of their aesthetic design, which are usually not easy to reconcile with the mentioned functional requirements and the loads occurring during their use. In particular, one will try here, the above-mentioned parts together with their connection, i. the connection of the backrest to the support frame, as slim as possible and not too burdensome perform and still ensure the functional properties.

In the EP 1 849 378 A1 a chair is shown in which is provided for connecting the backrest to the tubular frame of the chair designed in the form of a double-curved metal bracket backrest attachment. This metal strap lets Insert into a specially provided slot in the backrest and lock, the other end of the metal bracket with the support frame of the chair is connected. Since the metal bracket required for this purpose has to be specially turned and the assembly is relatively complex due to the connection of various individual elements, this form of connection from manufacture technical, but also from a technical point of view is disadvantageous.

In the DE 20 2004 016 238 U1 is a chair with armrests and a partially flexible, one-piece shell part, which includes both the seat and the back part attached thereto, mounted on a tube frame of a cantilevered chair. The backrest of the shell part is connected to corresponding pipe sections which form the armrest. The connection is made here via a connection unit consisting of a plurality of parts which are screwed by means of a screw to the pipe section. Again, there is the problem that with large, applied to the back forces, this attachment screw can solve over time. In addition, very many individual elements are required for this type of attachment of the backrest to the support frame, on the one hand bring additional costs and on the other hand require a complex, complex assembly process.

In the EP 993 794 A1 is a chair with a tubular support frame, which carries a seat and a backrest provided. Furthermore, the support frame on armrest bracket, which has above the seat substantially horizontally extending pipe portions. The backrest has integrally formed, acting as armrests arms. The pipe sections are inserted into specially provided holes within the armrests and bolted to the pipe sections of the support frame via appropriate fastening screws. The problem with this type of connection of the backrest or the attached armrests is that at a load on the backrest creates a torque in the lateral connections of the armrest. This torque causes a heavy burden on the mounting frame mounted mounting screws, which can lead to failure of this attachment in the long term.

Against this background, the present invention has the object, in a support frame having seating to allow a very secure connection of the backrest, which is also preferably easy to install and is inexpensive to produce.

PRESENTATION OF THE INVENTION

According to the invention this object is achieved by a chair frame with the features of claim 1 and / or by a chair with the features of claim 8 and / or by a method having the features of claim 12 and / or by a tool having the features of claim 15 ,

• Ein Stuhlgestell für ein Sitzmöbel, insbesondere einen Freischwinger oder eines Mehrbeinstuhls, mit einem Tragegestell, welches zwei obere Endabschnitte zur Befestigung des Tragegestells an einer Rückenlehne des Sitzmöbels aufweist, wobei ein jeweiliger Endabschnitt einen konisch ausgeformten Auszug aufweist, der bei der Montage des Tragegestells mit der Rückenlehne in ein entsprechendes konisch zulaufendes, hülsenförmiges Aufnahmestück der Rücklehne einführbar ist.
• Ein Sitzmöbel, insbesondere Freischwinger oder Mehrbeinstuhl, mit einer Rückenlehne, die Armlehnenstreben mit konisch zulaufenden, hülsenförmigen Aufnahmestücken aufweist, mit einem erfindungsgemäßen Stuhlgestell, dessen Endabschnitte in entsprechende Aufnahmestücke der Armlehnenstreben angeordnet und befestigt sind, mit einem Sitz, der an dem Stuhlgestell und/oder der Rücklehne befestigt ist.

• Ein Verfahren zur Herstellung eines erfindungsgemäßen Stuhlgestells, mit den Schritten: (a) Einlegen eines Tragegestells für ein Sitzmöbel in ein Werkzeug, wobei das Tragegestell zumindest zwei Endabschnitte mit konstantem Durchmesser aufweist; (b) Pressen und Ziehen des Tragegestells im Bereich des Endabschnitts in axiale Richtung zur Erzeugung des konisch zulaufenden Auszugs; (c) Eindrücken eines Abschnitts des Endabschnitts in radialer Richtung zur Erzeugung der schienenförmigen Einstülpungen; wobei die Schritte (b) und (c) in einem einzigen, gleichzeitig durchgeführten Arbeitsschritt ausgeführt werden.
• Ein Werkzeug zur Durchführung des erfindungsgemäßen Verfahrens, mit einer Halterung zur Aufnahme und Fixierung jeweils eines rohrförmigen Endabschnitts des Tragegestells, mit einem U-fömigen Gesenk zur umformenden Bearbeitung des in der Halterung fixierten Endabschnitts, welches eine Ausnehmung aufweist, deren Innenkontur eine Negativform des herzustellenden, konisch ausgeformten Auszugs des Endabschnitts bildet, mit einer in der Halterung oder dem Gesenk vorgesehenen schienenförmigen Prägeausstülpung, mit einer Hebeeinrichtung, über die die Halterung relativ zum Gesenk derart bewegbar ist, dass ein auf der Halterung vorgesehener rohrförmiger Endabschnitt zur Erzeugung des konischen Auszugs in die Ausnehmung pressbar ist und gleichzeitig sich die schienenförmige Prägeausstülpung zur Erzeugung der schienenförmigen Einstülpung in den Endabschnitt presst.

Accordingly, it is provided:

• A chair frame for a chair, in particular a cantilever chair or a multi-leg chair, with a support frame, which has two upper end portions for attachment of the support frame to a backrest of the chair, wherein a respective end portion has a conically shaped drawer, which in the assembly of the support frame with the Backrest is inserted into a corresponding tapered, sleeve-shaped receiving piece of the backrest.
• A seating, in particular cantilever chair or multi-legged chair, with a backrest, the armrest struts having tapered, sleeve-shaped receiving pieces, with a chair frame according to the invention, the end portions in corresponding receiving pieces of the armrest struts are arranged and fixed, with a seat which is attached to the chair frame and / or the backrest.

• A method of manufacturing a chair frame according to the invention comprising the steps of: (a) placing a support frame for a chair in a tool, the support frame having at least two constant diameter end portions; (B) pressing and pulling the support frame in the region of the end portion in the axial direction to produce the tapered drawer; (c) impressing a portion of the end portion in the radial direction to produce the rail-shaped indentations; wherein steps (b) and (c) are performed in a single concurrent operation.
• A tool for carrying out the method according to the invention, with a holder for receiving and fixing each of a tubular end portion of the support frame, with a U-shaped die for transforming the fixed in the holder end portion having a recess whose inner contour is a negative mold of the produced, a conically shaped extension of the end portion forms, with a provided in the holder or the die rail-shaped Prägeausstülpung, with a lifting device over which the holder is movable relative to the die such that a provided on the holder tubular end portion for generating the conical extension into the recess can be pressed and at the same time presses the rail-shaped Prägeausstülpung to produce the rail-shaped invagination in the end portion.

The finding underlying the present invention is, in a chair, such as a partner chair and in particular a cantilever chair, on additional fasteners, such as bolts, connecting sleeves and the like, to give up. Rather, according to the invention, a mounting technology very simple connection of the backrest to the support frame of the chair is provided by the fact that on the one hand there is a direct and direct connection of the backrest to the support frame. Further, the support frame has at its end portions, over which the support frame is to be attached to the backrest, a conical extension (outer shape), which can be plugged into a corresponding sleeve-shaped receptacle of the backrest, which has a corresponding conical inner shape. This tapered, sleeve-shaped receiving piece of the backrest can be produced in a simple manner, for example by an injection molding process. The conically shaped extract in the region of the end portion of the support frame can also be very easily produced by a corresponding pressing and drawing process.

By now this extract is conical, it can thus to a certain extent provide a self-aligning connection between the end portions of the support frame and the corresponding sleeve-shaped receiving pieces of the backrest, which is montagetechnisch of particular advantage. For the connection of these two elements are - with the exception of the corresponding fastening means for securing the end portions of the respective receiving piece - no additional elements required. As a result, the mounting of the backrest to the support frame designed very simple, since only a few assembly steps are required. In addition, this form of connection is also inexpensive to produce. Overall, a corresponding seating furniture can thus be produced in terms of assembly technology simply and, moreover, cost-effectively, as a result of which such seating furniture is particularly well suited for mass production.

Advantageous embodiments and further developments of the invention will become apparent from the other dependent claims and from the description with reference to the drawing.

In a particularly preferred embodiment, a respective end portion has a rail-shaped indentation. This rail-shaped indentation serves to guide the end portion during insertion of this end portion into the respectively corresponding receiving piece of the backrest. In addition, these rail-shaped indentations in the assembled state prevent rotation of these end portions of the support frame relative to the corresponding receiving pieces of the backrest, if the backrest also has corresponding rail-shaped protuberances. In this way, an undesirable loading of fastening screws for fastening the receiving piece to an end portion under load of the backrest is very effectively prevented.

In a particularly preferred embodiment, a respective indentation extends from a circumference of the end portion in the radial direction inwards. In addition, an indentation also extends in a straight line in the axial direction up to an open end of the respective end section.

In one embodiment, a respective indentation has a constant width and / or a constant depth in the axial direction. This is particularly preferred for assembly reasons, but also for reasons of production. In addition, of course, would also be conceivable if the end portions widen in the axial direction to the open end of the end portion and / or have an increasing depth.

In a typical embodiment, an end portion has at least one through hole. This hole allows the backrest to be attached to the support frame. For this purpose, during assembly, a respective end portion is positioned in a respective sleeve-shaped receiving piece of the backrest so that a bore also present in the receiving piece is arranged in alignment with the bore in the end portion. The attachment then takes place via a suitable fastening means, which may be formed, for example, as a screw, bolt, pin, rivet or the like. In the case of a screw this is screwed through the bore in the receiving piece into the bore of the end portion, said end portion for this purpose preferably has a sectionally present internal thread. Preferably, a hole is provided as a fastening means per end portion.

In a particularly preferred embodiment, the bore is provided in the end portion in the region of the indentation. Since these invaginations in the assembled state must receive a rotational movement under a load of the backrest, the forces can be better distributed by the arrangement of the bore and thus the corresponding fasteners in this invagination. In particular, the forces acting on the end portion are then lower because a lower torque acts due to the proximity to the axis of the end portion.

In a particularly preferred embodiment, the chair frame is made of a single and preferably a one-piece, curved support frame. This is particularly preferred in manufacturing technology, since only a single bending process is required for the production of the support frame. The corresponding stability can then be realized for example by a corresponding trained seat shell and backrest and possibly also by the choice of the material of the support frame.

In an alternative embodiment, the chair frame on a one-piece support frame. This one-piece carrying frame is made of a single, one-piece and curved carrying frame built. The required stability is realized here via crossbeams, which are provided between curved portions of the support frame and are secured thereto. The attachment is typically via a welded connection of the crossbars on the support frame, but can also be realized by screws, rivets and the like.

In a typical embodiment, the support frame is formed of a metallic tube. Such a tube can be particularly easy to bend manufacturing technology. In addition, the process of pressing and drawing for the production of the conical extracts in the region of the end sections in a metallic tube manufacturing technology is easily feasible. Preferably, the tube is formed of a 2STE 420, QSTE 420. In addition, of course, would also be conceivable if the support frame consists of a solid frame material. In this case, the support frame could be made thinner and thus filigree, which is sometimes advantageous for design reasons. If the stability and thus the rigidity of the support frame is in the foreground, very stable, little swinging cantilever chair or seating could be produced in this way.

In a typical embodiment, the tube of the support frame has a circular or oval cross-section. Conceivable, of course, would be other cross-sectional geometries, such as square or rectangular cross-sections.

In a typical embodiment, the support frame is galvanically coated. Depending on whether this coating is primarily intended to fulfill a functional or decorative purpose, galvanic coatings can be considered as different materials. In the case of a beautification of the support frame, so in the case of a decorative galvanic coating, z. As a Kunststoffgalvanisierung, chrome plating and the like in question. A functional galvanic Coating serves inter alia the corrosion protection. Galvanic coatings used for this purpose are realized by galvanizing, hard chrome and the like.

In a particularly preferred embodiment, the end portions of the support frame are open towards the end. A galvanic liquid used for the production of the galvanic coating on the support frame can thus leak out again after the galvanic treatment via the open ends. As a result, no galvanic liquid remains inside the tubular support frame.

In a particularly preferred embodiment of the seat according to the invention, a sleeve-shaped receiving piece has at least one inner rail-shaped recess. This rail-shaped formation is designed such that it is in the mounted state in direct engagement with a respective rail-shaped indentation of the extension of the tubular support frame. The directly engaging protuberances and indentations effectively absorb torques. In the assembled state is effectively prevented in this way that it can come under a load of the backrest, as may occur in a person sitting on the seat, to a rotational movement of the sleeve-shaped receiving pieces relative to the end pieces disposed therein and thus the corresponding conical extensions ,

In a typical embodiment, at least one further bore is provided in each case in a rail-shaped formation. This hole is arranged in the mounted state of the backrest with the chair frame in alignment with a corresponding bore of the drawer. The chair frame and the backrest can be fastened together by fastening means that are inserted through the further hole in the molding and the corresponding hole in the indentation. The fastening means can be designed here as a screw, pin, rivet or the like.

In a particularly preferred embodiment, the seating is designed as a cantilever chair. Such a cantilever typically has a one-piece and in particular one-piece chair frame, which two substantially vertical chair legs, a bent to the foot part, which is connected to the two chair legs, and two bent backwards backrest sections, which are to form the armrests and which have the end portions , includes.

In a particularly preferred embodiment, the backrest and the seat is divided, that is formed separately from each other and without direct direct connection between them.

Preferably, the backrest is fastened to the support frame exclusively at the two end sections, whereby the entire chair construction is given an open, appealing design. In addition, it would also be conceivable for the backrest to be fastened to a cross-member provided for this purpose between two parallel pipe sections of the support frame.

In an alternative embodiment, the backrest and the seat are formed together as a one-piece, contiguous part, in which a continuous, direct direct connection between the backrest and seat is present. Conveniently, the backrest is attached to corresponding end portions of the chair frame. The seat and possibly also the backrest can moreover be fastened to corresponding crossbeams which are arranged between parallel sections of the chair frame.

In a particularly preferred embodiment, the seat and / or the backrest is made of a single plastic molded part. This is particularly advantageous when the backrest and the seat are formed from a single, one-piece part. Preferably, this plastic molded part is produced as a plastic injection molded part.

In a typical embodiment, the chair frame has at least one crosspiece. About this cross-beam, the bent portions of the tubular support frame can be fixed against each other and thus increase the stability. The crossbeam is used in particular the support and the attachment of the seat to the support frame. The crossbeam is typically attached to a cantilever between parallel sections of the support frame. As a suitable attachment is a welded joint, which is particularly stable in the high forces acting on the chair. In addition, it would also be possible, the cross-beam over other fastening means, such. As screws, rivets and the like to attach to the support frame.

In a preferred embodiment of the method according to the invention, an additional step is provided which comprises drilling at least one bore in the region of the end portion of the support frame. In addition, here all steps (b), (c) and (d) are carried out in a single, simultaneously performed step. This is particularly particularly advantageous since, in particular, in the case of the island production, the handling step for producing the conically tapered drawer with inlets and holes provided therein is carried out in a single work step. The entire process of creating these end portions for connection to the backrest can thus be very effective and fast and thus produce cost.

Preferably, both end portions of the support frame are pulled out simultaneously, that is, in a single step, conically. This, too, significantly reduces the manufacturing time required to produce these tapered trays and helps to reduce the cost of producing these end sections. In a particularly preferred embodiment, the production of the chair frame takes place in a three-stage island process. In this case, the steps (a) to (c) or (a) to (d) designate a so-called handling and Assembly process performed after a bending process and a welding process.

• Einem Biegeprozess, bei dem das Rohrgestell des Stuhls in die gewünschte Endform gebogen wird;
• Einem Schweißprozess, bei dem die Verbindungen, wie z. B. Quertraversen, an das Rohrgestell angeschweißt werden;
• Einem Montageprozess (Handhabung), bei dem die Armauflagen, Sitzschale und Rückenlehne an das Rohrgestell befestigt werden.

It is generally desirable to reduce the manufacturing and assembly steps for the production of a cantilever in general and a partner chair in particular as possible and thus to simplify. In particular, in the industrial production of modern chairs, for efficiency reasons, very often an island production is carried out, which consists of at least three production steps:

• A bending process in which the tubular frame of the chair is bent to the desired final shape;
• A welding process in which the compounds, such. B. Crossbeams, are welded to the tube frame;
• An assembly process (handling) where the armrests, seat pan and back rest are attached to the tube frame.

These processes are typically performed one after the other. In order not to put up with any unnecessary delay in the process of this in-can production, it is desirable that each process take the same amount of time because the slowest process determines the speed of the entire production. By means of the method according to the invention, the production-intensive step can be significantly shortened, which is of particular advantage in the case of the island production.

In a particularly preferred embodiment of the tool according to the invention, the embossing protuberance has at least one first bore extending transversely through this embossing protuberance. In this case, a drilling device is provided, which is designed to drill through the first bore at least a second bore in the rail-shaped indentations generated in the end section by means of the embossing protuberance in the end section.

The above refinements and developments of the invention can be - if this is reasonable and practicable - on Combine any and appropriate way together.

CONTENT OF THE DRAWING

Fig. 1

ein erstes Ausführungsbeispiel eines erfindungsgemäßen Sitzmöbels;

Fig. 2, 2A

ein erstes und zweites, besonders bevorzugtes Ausführungsbeispiel eines erfindungsgemäßen Tragegestells;

Fig. 3 - 3B

eine erste besonders bevorzugte Ausgestaltung des konischen Auszugs des erfindungsgemäßen Tragegestells in verschiedenen Darstellungen;

Fig. 4

eine zweite, vereinfachte Ausgestaltung des konischen Auszugs des erfindungsgemäßen Tragegestells;

Fig. 5 - 5D

eine Rückenlehne zur Anbindung an ein erfindungsgemäßes Sitzmöbel in verschiedenen Darstellungen;

Fig. 6

anhand einer perspektivischen Darstellung eines Sitzmöbels ein erfindungsgemäßes Montageverfahren zur Erläuterung der Anbindung der Rückenlehne an das Tragegestell;

Fig. 7

ein zweites Ausführungsbeispiel eines erfindungsgemäßen Sitzmöbels;

Fig. 8

ein drittes Ausführungsbeispiel eines erfindungsgemäßen Sitzmöbels;

Fig. 9 - 9B

verschiedene Darstellungen eines erfindungsgemäßen Werkzeugs zur Herstellung eines erfindungsgemäßen Tragegestells.

The invention will be described in more detail with reference to the embodiments indicated in the schematic figures of the drawing. It shows:

Fig. 1

a first embodiment of a seat according to the invention;

Fig. 2, 2A

a first and second, particularly preferred embodiment of a support frame according to the invention;

Fig. 3 - 3B

a first particularly preferred embodiment of the conical extension of the support frame according to the invention in various representations;

Fig. 4

a second, simplified embodiment of the conical extension of the support frame according to the invention;

Fig. 5 - 5D

a backrest for connection to an inventive seating furniture in various representations;

Fig. 6

a perspective view of a chair an inventive mounting method to explain the connection of the backrest to the support frame;

Fig. 7

a second embodiment of a seat according to the invention;

Fig. 8

a third embodiment of a seat according to the invention;

Fig. 9 - 9B

various representations of a tool according to the invention for producing a support frame according to the invention.

In all figures of the drawing, the same and functionally identical elements - unless otherwise indicated - have been given the same reference numerals.

DESCRIPTION OF EMBODIMENTS

Fig. 1 shows a first embodiment of a seat according to the invention in a perspective view. The chair designated by reference numeral 10 is designed here as a cantilever. The cantilever 10 has a support frame 11, a seat 12 and a backrest 13.

The support frame 11 here has a metallic, round in cross-section designed as a tubular frame supporting frame 11. The seat 12 has a seat frame and an over-upholstery. The seat 12 lies on a in Fig. 1 not shown cross strut of the support frame 11 and is preferably mounted thereon by means of screws. The seat 12 is supported by the support frame 11. The backrest 13 also has an overholstery. The seat 12 and the backrest 13 are divided in this design of a cantilever and formed separately from each other, ie without direct direct connection between them. The connection of the backrest 13 to the support frame 11 via fastening screws 14, as will be explained in detail below.

Fig. 2 shows a first embodiment of a pipe frame 11 according to the invention. The pipe frame 11 has a U-shaped foot part 20. Of the foot part 20 is the tubular frame 11 bent vertically upwards, wherein the upwardly bent portions of the tubular frame 11 form two chair legs 21. The upper portions of the chair legs 21 are in turn bent at an angle or preferably horizontally backwards to the backrest 13, not shown here. The thus formed horizontal portions of the tube frame 11 form end portions 22 to which the backrest 13 can be fastened. These end portions 22 form in the assembled state of the cantilever 10 sections of the armrest.

Fig. 2A shows a second, particularly preferred embodiment of a tube frame according to the invention 11. In contrast to Fig. 2 is here to increase the stability between the two chair legs 21, a front cross-beam 23 is provided. This front cross-beam 23 connects the two chair legs 21 with each other and is preferably also made of a metallic tube. This cross-beam 23 may be provided as a straight continuous tube between the chair legs 21. Preferably, however, this cross-beam 23 is designed as a rearwardly to the backrest 13 toward U-shaped bent tubular frame. In this U-shape of the crossbeam 23, the seat 12 is placed during assembly and secured by suitable fastening means. This results in a higher rigidity and a better seating comfort, since in the loaded state of the seat 12, the forces can be absorbed more uniformly over the cross-beam 23.

The crossbeam 23 is attached to the two chair legs 21 via suitable fastening means. In the example shown, the cross-beam 23 is firmly connected via a welded joint 24 to the two chair legs 21. About this weld 24 ensures that even at high loads that act on the seat 12 on the crossbeam 23, a secure connection is guaranteed.

The end portions 22 of the chair frame 11 have an area 26 which is conically drawn towards the open end 25. This conical extract 26 will be described below with reference to 3 and 4 explained in detail.

Fig. 3 shows a first, preferred embodiment of the conical extension 26 in a perspective detail view.

Fig. 3A shows a bottom view and Fig. 3B shows a cross-sectional view of the conical extension 26. The conical extension 26 is frustoconical to its open end 25 formed. In this case, the diameter A1, A2 decreases in the region of the conical extension 26 in the axial direction X and towards the open end 25. The frustoconical conical extract 26 has on its underside an indentation 30. This indentation 30 extends in the axial direction X of the tube in the end section 22. The indentation 30 has a constant width B in the example shown. The indentation 30 forms a rail-shaped recess which extends to the open end 25. In the indentation 30 through a passage 26 through hole 31 is provided.

Fig. 4 shows a second embodiment of the conical extension 26. Although the diameter A1, A2 of the conical extension 26 decreases in the axial direction X out, but this has no rail-shaped indentation 30 on.

Fig. 5 shows a backrest 13 for connection to an inventive chair frame 11 in a perspective view. Fig. 5A shows the backrest Fig. 5 in a frontal representation and Fig. 5B shows a sectional side view of the backrest. The Fig. 5C shows a sectional side view of a detail of the backrest in the armrest and Fig. 5D shows the detail in a representation from below.

In the Fig. 5 to 5D illustrated backrest 13 is z. B. made of a plastic. The backrest 13 has a backrest portion 50, which in contrast to the backrest 13 in Fig. 1 slit-shaped, horizontally extending and substantially parallel recesses 57 has. From the backrest part 50, two struts 51 extend laterally in the direction of the chair frame 11, not shown here. These struts 51 serve, on the one hand, to connect the backrest 13 to the chair frame 11 and, in the mounted state, additionally to form an armrest for the chair 10. The struts 51 have in the front region over which the backrest 13 is to be connected to the chair frame 11, in each case a sleeve-shaped receiving piece 52. The structure of this sleeve-shaped receiving piece 52 will be described below with reference to Figs. 5A to 5D explained in more detail.

A respective sleeve-shaped receiving piece 52 is formed hollow inside. In addition, the sleeve-shaped receiving piece 52 corresponding to its open end 53 inwardly correspondingly tapered. In addition, the receiving piece 52 in the interior of a protuberance 54 which projects radially inwardly from an inner wall 56 of the receiving piece 52. This protuberance 54 is formed so that it can engage in the assembled state in the corresponding indentation 30 of the conical extension 36, thereby preventing a rotational movement of the receiving piece 52 to the extract 26 around. In addition, a continuous through the protuberance 54 bore 55 is provided, via which z. B. a countersunk screw through the receiving piece 52 can be inserted therethrough. By means of this screw can be mounted state, the receiving piece 52 to secure the conical extension 26. The bore 31 may for this purpose have an internal thread. Preferably, however, the bore 31 has no thread. In these cases, a thread-forming or self-tapping screw is used.

The following is based on the Fig. 6 an assembly method for connecting the backrest 13 to the chair frame 11 is explained:

The chair frame 11 is pushed with its end portions 22 and thus with the conical extensions located there 26 ahead in the corresponding sleeve-shaped receiving pieces 52 of the respective struts 51 and positioned accordingly (see dashed arrow). The end position of the backrest 13 on the chair frame 11 results when an outer surface 32 of the conical extension 26 bears firmly against the corresponding inner surface 56 of the sleeve-shaped receiving piece 52. This corresponds to a stop and thus an end position. The corresponding holes 31, 55 in the conical extension 26 and

in the sleeve-shaped receiving piece 52 are arranged in pairs to each other such that they are arranged in alignment at this position one above the other. In this case, fixing screws 60 can now be inserted through the bore 55 in the receiving piece and screwed into the bore 31 in the region of the conical extension 26. This results in a firm connection of the chair frame 11 with the backrest thirteenth

Fig. 7 shows a second embodiment of a designed as a cantilever chair according to the invention. In this example, the seat 12 and the backrest 13 are formed as a one-piece, continuous part. The backrest 13 is fixed on the struts 51 on the chair frame 11, whereas the seat 12 rests on the cross-beam 23. The chair frame 11 has floor elements 70 over which the foot part 20 rests on the floor as intended.

Fig. 8 shows a third embodiment of a seat according to the invention, which is designed here as a quadruped. The four chair legs 21 each have rollers 80 mounted on their underside, over which the chair 10 is also rollable. Again, the backrest 13 is attached via corresponding struts 51 on the chair frame 11.

The seat 12, which is fixed in a manner not shown with the four chair legs 21, is not with the backrest 13 connected. The backrest 13 also has no over-upholstery, but consists only of a ribbed backrest part 50 with corresponding side struts 51st

Fig. 9 shows a perspective view of an inventive tool for producing the chair frame. Fig. 9A and 9B show details of the tool. The tool is designated by reference numeral 90. This tool is adapted to a chair frame 11 according to the invention, as shown in FIG Fig. 1 is shown to produce. The tool 90 has a lower holder 91, which serves to receive and fix a tubular end portion of the chair frame 11.

Further, an upper bracket 92 is provided. The upper bracket 92 has a U-shaped die 93, which is provided for the forming processing of the fixed by the two brackets 91, 92 end portion 22. For this purpose, the U-shaped die 93 has a downwardly open recess 94, the inner contour of which imitates a negative mold of the conically shaped extension 26 of the end section 22 to be produced.

In the present example, a rail-shaped embossed protuberance 95 is provided in the region of the die 92 and in particular in its inner recess 94. This embossing protuberance 95 protrudes downwards from the recess 94 in the direction of the lower holder 91. Furthermore, a lifting device 96 is provided. The lifting device 96 in the present example serves the purpose of moving the lower holder 91 with the end section 22 of the chair frame arranged thereon upwards in the direction of the upper holder 92. This is done hydraulically in the example shown, but can also be done pneumatically or electrically. In this way, the end portion 22 can be pressed by means of the lower holder 91 upwards into the upper holder 92 and in particular into the recess 94 of the U-shaped Gesenk 93. It would also be conceivable if the upper support 92 is moved down to the lower bracket 91 out.

The upper holder 92 has a bore 96 extending transversely through the holder 92, the U-shaped die 93 and the embossing protuberance 95. Furthermore, a punching device 97, for example a punch 97, is provided. By means of a lowering device 98, the punching punch of the punching unit 97 can be lowered and punched into the indentation pressed by means of the stamping outfeed 95 in the region of the end section 22.

• Für die Erzeugung des Stuhlgestells 11 mit dem darin vorgesehenen Auszug 26 wird das Stuhlgestell 11 in umgekehrter Stellung, d. h. mit dem Fußteil 20 nach oben, in das Werkzeug 90 eingelegt. Hierzu werden die beiden Endabschnitte 22 in die jeweiligen unteren Halterungen 91 eingelegt und über entsprechende Halteteile 99 am Werkzeug 90 fixiert. Anschließend wird die untere Halterung 91 über die Hebeeinrichtung 96 nach oben in Richtung der oberen Halterung 92 gefahren. Dabei drücken sich die Endabschnitte 22 in die jeweiligen U-förmigen Gesenke 93. Dies erfolgt so lange, bis ein Anschlag erreicht ist. Ist dieser Anschlag erreicht, dann ist typischer Weise der Endabschnitt 22 vollständig in das U-förmige Gesenk 93 gepresst, wodurch die jeweiligen konischen Auszüge 26 erzeugt sind. Anschließend wird über die Absenkeinrichtung 98 die Stanzeinrichtung 97 nach unten bewegt, wodurch der Lochstempel 97 durch die gerade erzeugte Einstülpung 30 stanzt und
• dadurch die Bohrung 31 erzeugt. Anschließend wird die Absenkeinrichtung 98 wieder angehoben und die Hebevorrichtung 96 abgesenkt. Das so erzeugte erfindungsgemäße Stuhlgestell 11 kann aus dem Werkzeug 90 für eine Fertigmontage des Sitzmöbels entnommen werden.

Hereinafter, an inventive method for producing a chair frame based on Fig. 9 and 9B explains:

• For the production of the chair frame 11 with the extract 26 provided therein, the chair frame 11 in the reverse position, ie with the foot part 20 up, inserted into the tool 90. For this purpose, the two end portions 22 are inserted into the respective lower brackets 91 and fixed on the tool 90 via corresponding holding parts 99. Subsequently, the lower bracket 91 is moved over the lifting device 96 upwards in the direction of the upper bracket 92. In this case, the end portions 22 press into the respective U-shaped dies 93. This takes place until a stop is reached. When this stop is reached, then typically the end portion 22 is fully pressed into the U-shaped die 93, whereby the respective conical extensions 26 are produced. Subsequently, the punching device 97 is moved downwards over the lowering device 98, whereby the punch 97 punches through the just produced indentation 30 and
• thereby creating the bore 31. Subsequently, the lowering device 98 is raised again and the lifting device 96 is lowered. The chair frame 11 according to the invention thus produced can be removed from the tool 90 for a final assembly of the seat.

Preferably, the lifting of the lower bracket 91 and thus the formation of the conical extension 26 is carried out with the therein Injection 30 at the same time and in particular simultaneously with the punching of the bore 31.

Although the present invention has been described above with reference to a preferred embodiment, it is not limited thereto, but modifiable in many ways.

Thus, the invention does not necessarily relate exclusively to cantilever chairs, four-legged chairs and / or partner chairs, but can be used to advantage in any other chairs with armrest, such as in swivel chairs or other office chairs. Moreover, the present invention is not necessarily limited to the above-described constructions of the chair. Rather, the type of backrest, the seat, the support frame, the number of seat legs and the like can also be varied. The type and shape of acting as a guide rail inputs or protuberances are merely exemplary understood. The same applies to the type of attachment means of the armrest on the conical extension or about the seat and the cross-beam on the tube frame.

In the above embodiments, various materials for the support frame, the backrest, the seat, the armrest, etc. have been exemplified. However, the invention is not limited exclusively to these materials. Rather, these can be varied as desired without being diverted from the principle of the present invention.

LIST OF REFERENCE NUMBERS

10

Seating furniture, chair, cantilever chair, multi-legged chair

11

Carrying rack, tubular frame, chair frame

12

Seat

13

backrest

20

footboard

21

chair legs

22

end

23

Crossbar, cross strut

24

welded joint

25

open end of the end section / conical extension

26

conical extract

30

invagination

31

drilling

32

Outer surface of the conical extension

50

backrest area

51

pursuit

52

sleeve-shaped receiving piece

53

open end

54

protuberance

55

drilling

56

inner wall, inner surface

57

slot-shaped recess in the backrest

60

mounting screws

70

floor elements

80

roll

90

Tool

91

lower bracket

92

upper bracket

93

U-shaped die

94

recess

95

Prägeausstülpung

96

hoist

97

Punching device, punch

98

lowering

99

holding parts

B

Width of an invagination

X

axial direction of a conical extension / end portion

A1, A2

Diameter of the conical extension

Claims (15)

Chair frame (11, 23) for a chair (10), in particular for a partner chair (10),
a support frame (11) having two upper end portions (22) for attaching the support frame (11) to a backrest (13) of the seat (10), a respective end portion (22) having a conically shaped extension (26), in the assembly of the support frame (11) with the backrest (13) in a corresponding tapered, sleeve-shaped receiving piece (52) of the backrest (13) is insertable. Chair frame according to claim 1,
characterized,
in that a rail-shaped indentation (30) is provided as the respective end section (22), in particular that the indentation (30) extends inward in the radial direction from a circumference of the end section (22) and that the indentation (30) extends in the axial direction ( X) to an open end (25) of the end portion (22). Chair frame according to claim 2,
characterized,
that the indentation (30) has a constant width (B) and / or has a constant depth in the radial direction. Chair frame according to one of the preceding claims
characterized,
that an end portion (22) has at least one through hole (31), said bore (31) in particular in the indentation (30) is provided. Chair frame according to one of the preceding claims,
characterized,
in that the chair frame (11, 23) consists of a single, integrally formed and curved support frame (11) or that the chair frame (11, 23) has an integral support frame (11) which forms a single, integrally formed and bent support frame (11) and at least one between transverse portions of the support frame (11) provided cross-beam (23). Chair frame according to one of the preceding claims
characterized,
that the supporting frame (11) of a metallic tube, in particular a ZSTE 420 / QSTE 420 is formed, the tube of the support frame (11) in particular having a circular or oval cross-section. Chair frame according to one of the preceding claims
characterized,
in that the support frame (11) is galvanically coated and / or that the end sections (22) of the support frame (11) are open towards the end (53) thereof. Seating furniture (10), in particular cantilever chairs (10) or multi-legged chairs (10),
with a backrest (13), the armrest struts (51) with tapered inner, sleeve-shaped receiving pieces (52),
with a chair frame (11) according to one of claims 1 to 7,
the end portions (22) of which are arranged and fixed in corresponding receiving pieces (52) of the armrest struts (51),
with a seat attached to the chair frame (11) and / or the backrest (13). Seating furniture according to claim 8,
characterized,
in that a sleeve-shaped receiving piece (52) has an inner rail-shaped formation (54) which, in the installed state, is in direct engagement with a respective rail-shaped indentation (30) of the drawer (26) of the tubular support frame (11), wherein in particular a rail-shaped formation each having at least one further bore (55) which is arranged in the mounted state in alignment with a corresponding bore (31) of the drawer (26), and that the chair frame (11, 23) and the backrest (13) via fastening means (60) are fastened together. Seating furniture according to one of claims 8 or 9,
characterized,
in that the backrest (13) and the seat (12) are designed to be split, wherein in particular the backrest (13) is fastened exclusively to the support frame (11) via the two end sections (22) or the backrest (13) and the seat (13) 12) are formed together as an integral part. Seating furniture according to one of claims 8 to 10,
characterized,
in that the seat (12) and / or the backrest (13) are produced from a single molded article and / or that the chair frame (11, 23) has at least one crosspiece 23. Method of manufacturing a chair frame (11, 23) according to one of claims 1 to 7, comprising the steps: (A) inserting a support frame (11) for a seating (10) in a tool 90, wherein the support frame (11) has at least two end portions (22) with a constant diameter (A1, A2); (B) pressing and pulling the support frame (11) in the region of the end portion (22) in the axial direction (X) to produce the tapered drawer (26); (c) impressing a portion of the end portion (22) in the radial direction to produce the rail-shaped indentations (30); wherein steps (b) and (c) are performed in a single concurrent operation. Method according to claim 12,
marked by
the next step: (d) drilling at least one bore (31) in the region of the end section (22), wherein steps (b), (c) and (d) are performed in a single concurrent operation. Method according to one of claims 12 or 13,
characterized,
that both end portions (22) are conically extended simultaneously in a single operation and / or that the manufacture of the chair frame (11, 23) takes place in a three-stage island production process, wherein steps (a) - (d) denote a handling process after a bending process and a welding process is performed. Tool (90) for carrying out the method according to one of claims 12 to 14,
with a holder (91, 92) for receiving and fixing in each case a tubular end section (22) of the carrying frame (11),
with a U-shaped die (93) for deforming the end portion (22) fixed in the holder (91, 92), which has a recess (94) whose inner contour is a Forming a negative mold of the conically shaped extension (26) of the end section (22) to be produced,
with a rail-shaped embossment protuberance (95) provided in the holder (91, 92) or the die (93),
with a lifting device (96), via which the holder (91, 92) is movable relative to the die (93) in such a way that a tubular end section (22) fixed on the holder (91, 92) is produced to produce the conical extension (26). in the recess (57) can be pressed and at the same time the rail-shaped Prägeausstülpung (95) for generating the rail-shaped indentation (30) in the end portion (22) pressed.

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