EP2617325B1 - Backrest for a seat - Google Patents

Description

The invention relates to a backrest for a chair, in particular in the form of a work chair, as a bench, as lounge furniture and the like.

Backrest shells whose inner surfaces consist of an elastic structure are basically known in the art.

With the EP 0 857 444 A2 is such a back shell has become known in which, however, a two-part structure, which means that the structure shown there is not a belt structure, but a network structure and consists of two mutually parallel and mutually spaced grid planes, the two network levels as a separate Part are mounted in a revolving back frame.

The attachment of the known mesh or grid structure done in the EP 0 857 444 A2 or the WO 2010/011633 A1 or the DE 103 92 285 T5 in that the lattice structure is produced as a separate part and is subsequently connected to the circumferentially closed backrest frame.

Such a subsequent connection is done for example by hanging in associated frame-side suspension elements such. As nails or screws or by gluing and the like connecting means more.

Disadvantage of the known backrests with an elastic belt structure is therefore that a great deal of effort between the connection of the inner, elastic belt or network structure and the outer, circumferential backrest frame is given.

It requires more assembly operations to attach such a belt, grid or mesh structure with the revolving back frame, which is associated with the further disadvantage that such a connection can be solved even with prolonged use again, resulting in considerable repair.

Difficulties make especially the fit between the meshed in a revolving back frame grid or Gurtwerk because the joining technique used for this subject is subject to large tolerances and unsightly joints arise that must be subsequently disguised, covered or covered with an appropriate material.

It involves several separate manufacturing processes, wherein in the first manufacturing process, the belt structure of the inner part must be made and in a second manufacturing process of the revolving back frame and in a third manufacturing process, the two parts must be joined together, which is associated with the disadvantages described above.

In addition to the high production costs, the further disadvantage is that the registered from the upper body of the seated person on the inner belt or lattice support forces are not fully transferable to the back frame, because in the connecting region between the inner elastic structure and the rigid back frame different type of fasteners are arranged so that a material integral, circumferential and especially non-positive connection between the inner elastic belt structure and the revolving back frame is disturbed by the intermediate connection plane.

It follows that a very high manufacturing and manufacturing effort is required because in two different injection processes, the inner belt structure and with another injection process, the outer circumferential back shell must be made.

The invention is therefore the object of a method and a backrest worked by the method for a piece of furniture to form so that at high comfort for the human upper body, the backrest is formed from an inner elastic grid or harness and in a simple way with the surrounding frame can be connected.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

Characteristic of the invention is, inter alia, provided that the backrest is formed consisting of the frame-side back shell and the inner recess filling elastic belt or band structure of a material einstückeinteiligen plastic part.

It is essential that in a single process step in a plastic injection molding tool suitable for this purpose, both the circumferential backrest shell designed as a frame and at the same time the belt or band structure forming the elastic inner part are produced.

Merely for linguistic simplification reasons, an elastic belt structure for the material of the inner part of the back frame is assumed in the following description.

A feature of the invention is that a back consisting of a uniform plastic part consisting of at least one back shell, which preferably forms a circumferentially closed back frame, material-uniformly connected to an internal belt or band structure of a plurality of intersecting strap bars or bands , The two parts are produced in a single operation in a plastic injection molding tool and bonded cohesively during the injection process.

This means that the two parts form a material-integral plastic part and thus forms the inner belt structure cohesively with the encircling, the back shell forming back frame a single continuous interruption-free material einstückiges part.

By using an injection molding tool working with several plastic components (eg a 2K or 3K injection molding tool), it is now possible for the plastic material of the inner belt structure to use a different (elastic) plastic material than a comparative one Hard plastic material for the surrounding backrest frame, which forms the backrest shell.

This makes it possible for the first time to ensure a very rigid structure for the backrest frame, which provides absolute stability, bending strength and breaking strength, in the backrest frame inwardly directed cavities are formed, which form a connecting plane to the circumferential belt frame of the inner part and the two parts are cohesively joined together in the connection area by the plastic material used during the injection molding process.

Because of the possibility of using two different plastic materials for the back shell and for the inner belt structure, there is the further advantage that now the belt structure z. B. may be formed of a different colored plastic material as a comparatively the circumferential back shell.

Another advantage is that a plastic material for the inner belt structure a very elastic plastic material such. As PP-EPDM can be selected, while for the material of the revolving back frame of the back shell forms a harder plastic material is selected, namely. a material PP + GF.

The latter is a glass fiber reinforced plastic as material for the revolving backrest frame.

The term PP is called polypropylene and is to be understood only as an example of a favorable choice of plastic. Of course, the invention extends to all known and suitable plastic materials such. As polyamide (PA) or any other plastic material.

Important in the invention is that in an injection molding the material einstückige production of a complete backrest with elastic inner part takes place, in a simple embodiment, the back shell consists of a revolving fins frame, and this remains open, as the back frame with the other parts of the inner, elastic backrest structure is materially connected.

It is known that a backrest frame z. B. to connect via a lower, horizontal backrest bar with the support mechanism of a work chair, the backrest bar may be connected in a first embodiment of the invention as a separate part with the circumferential back shell and z. B. by screwing, riveting, gluing, plugging or locking can be connected to the back shell.

In a second preferred embodiment of the invention, however, it is provided that at the same time the backrest bar is injection-molded on the back shell and forms a material integral part with this to ensure that the backrest completely with a backrest bar and the back shell and the inner belt structure consists of a material integral part, so that the molded on the back shell backrest bar can be directly connected to the seat mechanism of the work chair.

The term "material integral" part means that at least the back shell and the internal elastic belt structure consist of a (same or different) plastic material, it does not matter that the plastic materials used are identical. The two parts are only materially connected to each other.

The term "material integral" thus means only the fact that the two parts are made of a plastic material and are materially interconnected, wherein the invention can also provide that these plastic materials are different from each other. The term "cohesive connection" refers to all compounds in which the connection partners are held together by atomic or molecular forces. They are at the same time non-detachable connections, which can only be separated by destruction of the connecting means

The present invention thus differs from the material integral production of a backrest z. B. of camping chairs, which have a particularly simple way a continuous made of a material backrest, but with regard to the suspension comfort between the inner part of the back shell and the revolving back frame no difference is made.

Such backrests for camping chairs are with respect to the inner part and the back frame to continuous plastic materials that have no suspension comfort. The suspension comfort in such camping chair backrests is made only by the slot geometry of the backrest structure and the cross sections used.

If a certain elasticity of a backrest of a camping chair is desired, you can buy the elasticity of the inner part with an increased risk of breakage of the outer backrest frame.

This is where the invention, which proposes a very stable, unbreakable and preferably revolving back frame, the z. B. also consists of a reinforced fiberglass material and has molded in its inner part a highly elastic belt structure material integral, so that the two parts form a single part and still a very high Abstützkomfort is given by the internal elastic belt structure according to the invention.

The material in one piece injection molding of the plastic material of the inner elastic belt structure to the peripheral connecting portions of the back frame results in the further advantage that now no foreign connecting means between these two plastic parts are present, which complicate or affect a load transfer between the two parts, as at the subject of EP 0 857 444 A2 had to be accepted.

This ensures a completely consistent support comfort over the entire surface of the inner part, because the inner elastic belt structure is connected on all sides and circumferentially firmly and cohesively with the inner sides of the rigid back frame.

It is essential that the outer back frame forms the cavity for receiving the circumferential inner belt frame, which forms the elastic belt structure with its inner surface.

According to the invention, it is provided that the belt structure consists of a plurality of mutually crossing at an acute angle chord members, the chord members between them diamond-shaped acute-angled recesses to ensure good elasticity support.

The strap bars are substantially obliquely or diagonally extending over the backrest and form between them the diamond-shaped recesses, but the present invention is not limited to such a strap structure.

In a non-inventive embodiment, it is provided that the belt bars between them form round, oval or slot-shaped recesses, so that the invention is not directed to an elastic diamond-shaped belt structure for the interior of the back shell.

Not within the scope of the invention, an elastic belt or band structure is provided, which consists in any way of intersecting straps or bands, these straps or bands between them form suitable recesses, so as to provide a good material and a good elasticity and elasticity comfort to reach the inner part.

The larger the recesses between the strap bars, the higher the elasticity in this area.

For this reason, the invention provides that the largest, diamond-shaped, recesses are formed in a vertical center axis of the belt structure and that connect from the vertical center axis to the left and right smaller diamond-shaped structures, so the greatest elasticity of the belt structure in the vertical Achieve center axis of the backrest.

The invention provides various elasticities in an upper back region, a middle back region and in a lordosis region, wherein it is provided according to a special feature of the invention that the belt structure in the lordosis region is directed against the back, ie is convex and thus provides a special support in the lordosis of the human spine.

Another variation on which the invention is directed is to vary the thickness of the strap bars across the width and height of the strap structure.

So it is z. B. provided that strap bars are arranged with a thinner cross section in the upper shoulder region of the backrest structure and the strap bars are arranged with the thicker cross-sectional area in the lordosis region.

As a result, the supporting effect of the belt structure in the lordosis region is reinforced and in the overlying back region, the support effect is weaker, but elastic.

This results in a very good Abstützkomfort for the human back, which varies over the vertical center axis of the backrest.

The subject of the present invention results not only from the subject matter of the individual claims, but also from the combination of the individual claims with each other.

All information and features disclosed in the documents, including the abstract, in particular the spatial design shown in the drawings, are claimed to be essential to the invention insofar as they are novel individually or in combination with respect to the prior art.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Figur 1:

Draufsicht auf eine Rückenlehne nach der Erfindung.

Figur 2:

Schnitt gem. der Linie A-A in Figur 1 (vertikale Mittelinie).

Figur 3:

Seitenansicht der Rückenlehne nach Figur 1.

Figur 4:

Schnitt gem. der Linie C-C in Figur 4.

Figur 5:

Schnitt gem. der Linie B-B in Figur 1.

Figur 6:

Die separate Darstellung der Gurtstruktur ohne Verbindung mit dem umlaufenden Lehnenrahmen.

Figur 7:

Schnitt gem. der Linie A-A in Figur 6.

Figur 8:

Seitenansicht der Gurtstruktur nach Figur 6

Figur 9:

Schnitt gem. der Linie B-B in Figur 6

Figur 10:

Schnitt durch einen Gurtstab in Höhe der Position 16 in Figur 6.

Figur 11:

Schnitt durch einen Gurtstab in Höhe der Position 17 nach Figur 6.

Show it:

FIG. 1:

Top view of a backrest according to the invention.

FIG. 2:

Cut acc. the line AA in FIG. 1 (vertical center line).

FIG. 3:

Side view of the backrest after FIG. 1 ,

FIG. 4:

Cut acc. the line CC in FIG. 4 ,

FIG. 5:

Cut acc. the line BB in FIG. 1 ,

FIG. 6:

The separate representation of the belt structure without connection to the revolving backrest frame.

FIG. 7:

Cut acc. the line AA in FIG. 6 ,

FIG. 8:

Side view of the belt structure after FIG. 6

FIG. 9:

Cut acc. the line BB in FIG. 6

FIG. 10:

Cut through a belt bar equal to position 16 in FIG. 6 ,

FIG. 11:

Cut through a strap bar at the height of position 17 FIG. 6 ,

In the embodiment shown in the drawings, it is merely exemplified that the backrest 1 consists of a back shell 2, which forms a circumferential back frame 20, which defines an inner opening, in which an elastic belt structure 4 is injected, so that this inner belt structure 4 cohesively is connected to the inner surfaces of the back frame 20.

The embodiment shows that at the same time still required for connecting the backrest 1 with the base of the chair backrest bar 3 is molded einstoffeinstückig with the back shell of a continuous one-piece part.

However, as has already been pointed out in the general part of the description, the invention is not limited thereto. It could also be the lower backrest bracket 3, which carries suitable fasteners for attachment to the seat mechanism, also be connected as a separate part with the back shell 2 and formed by the back shell 2 back frame 20.

The embodiment shown here is not intended to limit the scope of the invention.

It is important that an inner elastic belt structure 4 is provided consisting of a plurality of intersecting belt bars 5, wherein the belt bars 5 form between them acute-angled recesses 6 in diamond shape, so as to ensure an excellent supporting elasticity of the belt structure 4.

The part of the back shell 2 forming, all-round back frame 20 forms an inner central recess 18, which is filled by the belt structure 4 according to the invention, wherein the side surfaces of the belt structure form a belt frame 8.

The belt frame 8 engages in an associated cavity 9 on the revolving back frame 20 and is connected in the region of a connecting region 7 with the plastic material with the back shell 2 cohesively.

It is important that the inner belt structure 4 forms a circumferential belt frame 8, wherein the circumferential belt frame 8 are formed from the same plastic material as the belt bars 5. The belt frame 8 forms marginal connection areas 7, which engage in a arranged in the back frame 20 circumferential cavity 9 and there are integrally connected to the plastic material of the back frame 20 in an injection mold.

The invention is not limited to the fact that the belt structure 4 has a circumferential belt frame 8 and therefore also not that the total central recess 18 in the revolving back frame 20 is also formed circumferentially.

It could therefore also be possible that the lower transverse frame portion 19 of the back frame 20 is omitted, which is then open there. Similarly, an upper frame portion 21 omitted at the top of the back shell 2, so that there is the back frame 20 is open.

The invention is therefore not limited to a self-contained recess 18 for a revolving back frame 20, but in another embodiment, it may be provided that the back frame 20 z. B. up in the frame area 21 or below in the frame area 19 or in both frame areas 19 and 21 is open.

In the FIGS. 6 to 9 the separate belt structure 4 is exemplified, wherein it is essential that the belt structure 4 is never present in the embodiment shown as the sole part, but is always molded in a 2K or 3K-injection mold to the rotating back frame 20 of the back shell 2.

Only the better graphic clarification because of the show FIGS. 6 to 9 the structure of the separate belt structure. 4

It can be seen that the belt bars 5 extend mirror-symmetrically to the longitudinal center line 23 and relative to a single belt bar can be seen that z. B. the belt bar 5a continues around a curve portion 22 in a material integrally adjoining thereto belt bar 5b, so that in an injection molding tool, so to speak, a belt structure 4 continued from infinite chordsticks. The respective belt bars 5a, 5b are materially connected to one another via the curved connecting regions 22 and continue, as it were, as a latticework, thus forming an unbroken belt structure 4.

Thereby, a high elasticity and support comfort is achieved, although the belt structure 4 consists of the endlessly extending chord members 5a, 5b of the same plastic material as well as the adjoining areas of the belt frame 8, which include the outer region of the belt structure 4 and thus narrow ,

The outer belt frame 8 in turn consists of a very thin plastic material which corresponds approximately to the thickness of the chord members 5, wherein it is provided in a preferred embodiment that the thickness of the belt frame 8, on which the chord members 5 are molded about z. B. 4 millimeters, while the thickness of the strap bars is about 5 millimeters.

Out FIG. 7 It can be seen that in the lumbar region 24 another support structure of the strap bars 5 is used, as is also the case FIG. 11 results. There, it can be seen that the belt bars 5a have approximately a diamond-shaped profile and the width 12 and height 15 of the thicker belt bars 5a thus formed differs from the thinner belt bars 5b FIG. 10 in that another dimension for the width 13 and the height 14 was selected.

In a preferred embodiment, only the width 12 is greater than the width 13, wherein the heights 14 and 15 are the same. However, the invention is not limited thereto; It can also be provided that the heights 14 and 15 of the different strap bars 5a, 5b are different.

Out FIGS. 7 and 8 It can still be seen that the entire belt structure 4 forms a lordosis support region 25 directed against the back of the user, ie the entire belt structure is convexly turned outwards in this area and directed against the back of the user.

drawing Legend

1.

backrest

Second

backrest shell

Third

sit Ironing

4th

belt structure

5th

strap bar

5a.

strap bar

5b.

strap bar

6th

recess

7th

connecting area

8th.

belt frame

9th

Cavity (in 2)

10th

of draft

11th

angle

12th

width

13th

width

14th

height

15th

height

16th

position

17th

position

18th

Recess (total for backrest frame)

19th

Frame area (from 20)

20th

back frame

21st

Frame area (from 20)

22nd

curve area

23rd

Longitudinal center line

24th

lordosis

25th

Lordosestützbereich

Claims (10)

1. Backrest (1) for a seating unit, in particular in the form of a work chair, bench seat, lounge furniture and the like, consisting of a backrest frame shell (2) which forms an inner central opening (6) which is filled with an elastic strap or band structure (4) which at the edge is connected with an intimate material connection with the backrest frame shell (2), characterised in that the strap structure (4) consists of a multiplicity of strap members (5, 5a, 5b) which intersect with one another at an acute angle, wherein the strap members (5, 5a, 5b) form between them diamond-shaped acute-angled openings (6) in order to ensure good supporting elasticity, and in that the largest diamond-shaped openings (6) are formed in a vertical central axis (23) of the strap structure (4) and in that departing from the vertical central axis (23) to the left and right there are adjoining smaller diamond-shaped structures in order to achieve the greatest elasticity of the strap structure in the vertical central axis of the backrest.
2. Backrest according to claim 1, characterised in that the backrest (1) consisting of a uniform plastic part consisting of at least one backrest shell (2) which forms a backrest frame (20) with a closed circumference, is connected with a uniform material connection with a strap or band structure (4) located on the inside and formed of a multiplicity of intersecting strap members (5, 5a, 5b) or bands.
3. Method for producing a backrest and backrest shell assembly according to claim 1 or 2, characterised in that the two parts (2 and 4) are produced in a single working operation in a plastic injection moulding tool and are connected with one another with an intimate material connection during the injection moulding operation.
4. Backrest according to one of claims 1 or 2, characterised in that the two parts (2 and 4) form a one-piece material plastic part and the inner strap structure (4) forms a single continuous one-piece material part free of breaks with the surrounding backrest frame (20) forming the backrest shell (2) with an intimate material connection.
5. Backrest according to one of claims 1, 2 or 4, characterised in that the plastic material of the inner strap structure (4) is an elastic plastic material and the plastic material for the surrounding backrest frame is a hard plastic material.
6. Backrest according to one of claims 1, 2, 4 or 5, characterised in that arranged at the edge in the backrest frame (20) there are inwardly directed cavities (9) which form a connecting plane to the surrounding strap frame (8) of the inner part and both parts are connected to one another with an intimate material connection in the connecting region by the plastic material used during the injection moulding operation.
7. Backrest according to one of claims 1, 2, 4, 5 or 6, characterised in that the strap structure (4) is formed of a differently coloured plastic material than by way of comparison the plastic material of the backrest shell (20).
8. Backrest according to one of claims 1, 2, 4, 5, 6 or 7, characterised in that a lower backrest bow (3) for fastening to the seating unit is moulded to the underside of the backrest shell (2).
9. Backrest according to one of claims 1, 2, 4, 5, 6, 7 or 8, characterised in that different elasticities are provided in an upper back region, a middle back region and in a lumbar region and wherein the strap structure (4) in the lumbar region (24) is directed towards the back, i.e. is convex in form.
10. Backrest according to one of claims 1, 2, 4, 5, 6, 7, 8 or 9, characterised in that the strap members (4) with a thinner cross-section are arranged in the upper shoulder region of the backrest structure and the strap members (4) with the thicker cross-section region are arranged in the lumbar region (24).

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