EP2617326B1 - Backrest - Google Patents

Description

The invention relates to a backrest, which can be arranged on chairs or seats.

Backrests are used to improve seating comfort by supporting the lumbar area with the back support, while maintaining a natural posture.

The DE 692 08 398 T2 describes, for example, a back support for seats, in particular for motor vehicle seats, which has pivotable support elements which are pivotable about a vertical axis to each other, that the general hollow curvature of the support is variable.

The DE 196 42 765 A1 describes an adjustable lumbar support with an elliptical flexible panel that provides resistance when bent.

DE 2 040 794 A1 discloses a backrest according to the preamble of claim 1 of the present application.

Back braces are also known which consist of a fabric frame covered with a fabric, which is shaped so that the tissue takes the form of a saddle surface. However, it has been found that the steel frame is relatively stiff, so that the necessary elasticity of the back support is essentially provided only by the tissue.

Object of the present invention is to provide a back support of the aforementioned type, which is improved in sitting comfort.

According to the invention, this object is achieved with the subject matter of claim 1. It is proposed a cup-shaped back support for a seat comprising a frame and a stretched over the frame covering, wherein the frame is bent so that the fabric is curved in the form of a saddle surface, it being provided that the frame has at least one flexible portion which comprises at least one coil spring determining or at least co-determining the flexibility of the section, hereinafter referred to as "helical spring frame section".

In the flexible section, the back support adapts particularly well to the back contour, because the coil spring combines the advantage of sufficient bending stiffness with the advantage of high elasticity. The coil spring also offers the advantage that its mechanical properties can be adjusted within wide limits by varying the diameter of the coil, wire thickness and wire material.

The term "flexible" means that it is primarily "elastic Flexibility "is not provided for" plastic flexibility ", which would lead to a permanent deformation of the frame.

According to the invention, the frame has a plurality of helical spring frame sections, wherein at least two of these have different flexural stiffnesses by having different flexurally stiff helical springs. With this design, it is possible to tailor the properties of the back support even more targeted to the needs of the user.

It can further be provided that the helical spring frame section has a plurality of coaxially arranged coiled springs.

It can also be provided that the helical spring frame section has a plurality of helical springs disposed axially one behind the other. The coil springs may have a different flexural rigidity. Thus, for example, the support region of the back support, in which it rests on a seat surface, not or slightly elastic, the two side region may have a high elasticity and the upper connection region may have a relatively low elasticity.

The helical spring frame portion may comprise an inner frame member which passes through the coil spring or the coil springs. This frame element can be provided to predetermine the edge contour of the helical spring frame section in front of the elastic deformation occurring during use of the back support. The frame member may be formed, for example, of metal or plastic. The inner Frame member may serve to connect the coil spring or the coil springs to a frame portion.

The inner frame member may have a lower flexural rigidity than the coil spring or the coil springs of the coil spring frame portion.

It can be provided that the frame is formed as a closed or almost closed ring and having an inner frame on which at least partially a coil spring or a plurality of coil springs is arranged or are to form at least one coil spring frame portion. The term "ring" refers to a closed or nearly closed frame. The contour of the ring may e.g. be designed as a polygon with rounded corners or as an oval or the like, it need not be circular.

Embodiments are possible in which the frame is formed as a closed or nearly closed ring whose circumference consists exclusively of coil spring frame sections.

It can be provided that the frame is formed as a closed or nearly closed frame whose circumference consists of frame sections with different bending strength, wherein at least one of the frame sections, which has comparatively low bending stiffness, is designed as a helical spring frame section.

Furthermore, it can be provided that the inner frame element of the helical spring frame section and / or the inner frame at least partially formed as a pipe or rod made of metal or plastic. It can also be provided that a plurality of thin wires twisted into a rope form the frame element.

In a further advantageous embodiment it can be provided that the inner frame member and / or the inner frame of the frame is at least partially formed as a rod of twisted metal wires.

The inner frame element of the helical spring frame section and / or the inner frame of the frame may have a plastic coating and / or a plastic sheath, for example heat shrink tubing and / or be injected in preferably flexible plastic.

It can be provided that the helical spring frame section has a plastic coating and / or a plastic sleeve, preferably a screw tube, and / or is injected in preferably flexible plastic. As a result, the optical impression can be improved and / or the coil springs can be padded, so that it is prevented that thin objects, such as hair, textile fibers or the like, get between the screw coils and clamped there.

It can further be provided that helical springs arranged one behind the other are connected to one another within the helical spring frame section and / or two helical spring frame sections adjoining one another by a connecting element.

The connecting element can engage in associated end portions of the associated coil springs and / or engage the entire length of at least one of the springs to be connected.

It can be provided that the connecting element surrounds the associated end sections of the coil springs to be connected and / or the entire length of at least one of the coil springs to be connected. It can also be provided that the one end section of the connecting element engages through the helical spring and the other end section of the connecting element engages around the helical spring. The connecting element may, for example, have an external thread or an internal thread onto which the helical spring can be screwed, whereby a detachable connection is obtained. Advantageously, such a connecting element may be formed of two sections, which are interconnected by an axial pivot bearing. In a further advantageous embodiment, it can be provided to design the thread conically, so that manufacturing tolerances play no role. It can also be provided to permanently connect the connecting element and the helical spring with each other, for example by gluing.

The connecting element may have a greater flexural rigidity than the coil springs to be connected.

Fig. 1

einen Stuhl mit einer an der Stuhllehne montierten erfindungsgemäßen Rückenstütze in einer perspektivischen Darstellung;

Fig. 2

die Rückenstütze in Fig. 1 in einer schematischen Vorderansicht;

Fig. 3

den Rahmen der Rückenstütze in Fig. 2 in einer schematischen Vorderansicht;

Fig. 4

einen vergrößerten Ausschnitt IV eines ersten Ausführungsbeispiels des Rahmens in Fig. 3;

Fig. 5

einen vergrößerten Ausschnitt V eines zweiten Ausführungsbeispiels des Rahmens in Fig. 3;

Fig. 6

einen vergrößerten Ausschnitt VI eines dritten Ausführungsbeispiels des Rahmens in Fig. 3;

Fig. 7

einen vergrößerten Ausschnitt VII eines vierten Ausführungsbeispiels des Rahmens in Fig. 3.

The invention will now be explained in more detail with reference to exemplary embodiments. Show it

Fig. 1

a chair with a backrest mounted on the backrest according to the invention in a perspective view;

Fig. 2

the back support in Fig. 1 in a schematic front view;

Fig. 3

the frame of the lumbar support in Fig. 2 in a schematic front view;

Fig. 4

an enlarged detail IV of a first embodiment of the frame in Fig. 3 ;

Fig. 5

an enlarged detail V of a second embodiment of the frame in Fig. 3 ;

Fig. 6

an enlarged detail VI of a third embodiment of the frame in Fig. 3 ;

Fig. 7

an enlarged detail VII of a fourth embodiment of the frame in Fig. 3 ,

Fig. 1 shows a backrest 1 attached to a backrest of a chair 2 by means of an elastic tensioning belt 14.

The back support 1 has the shape of a saddle surface, that is, it is curved in the opposite direction in the two main directions. A correspondingly shaped annular frame 11 (see Fig. 2 and 3 ) is covered with a net-shaped fabric 12. The frame 11 has a frame covering 13, which forms a padding for the frame 11 and may be formed, for example, from a soft fabric.

The frame 11 is preferably formed of a frame spring 11f. It This is a helical spring, which is not stressed here on train or pressure, but bending in its longitudinal axis. Compared to prior art frames, which are formed from a steel tube or a steel wire, the frame according to the invention has a higher elasticity, without sacrificing basic strength. The frame 11 is formed of a plurality of axially successively arranged springs 11f. In the different areas of the frame 11 springs 11f are used with different bending stiffness.

At the rear of the frame 11 facing the backrest two spaced struts 15 are arranged, which consist for example of steel wire, wherein a tubular strut casing 16 improves the seating comfort. There are also modified versions possible in which the struts 15 are made of textile tape, wire rope, plastic rope, optionally as a net or fabric made therefrom, or in the form of a plate. In the various embodiments, the struts 15 in addition to the frame covering 13 contribute to the fact that the frame 11 is curved in the form of a saddle surface. There are also modified versions possible in which not only two struts 15 but three or more struts are provided. Furthermore, modified versions are possible in which only one strut is provided.

Fig. 5 shows an embodiment in which the frame spring 11 f is penetrated by an annular inner frame member 11 e, which in the in Fig. 5 illustrated embodiment is formed wire-shaped. The frame member 11e may be formed of spring steel. But it is also possible to form the frame member of an elastic plastic and to be used substantially as a connecting element connecting the frame spring 11f to the closed annular frame 11.

The 6 and 7 show embodiments in which one or more frame springs 11f are connected by rigid connecting members 11v to the closed annular frame 11.

This in Fig. 6 shown connecting element 11v is formed as a recessed at both end portions cylinder which engages with its end portions two adjacent frame springs 11f. The end portions may be glued, for example, in the frame springs 11f.

This in Fig. 7 illustrated connecting element 11v is designed as a trained at both end portions as a plug-in cylinder which engages around two adjacent frame springs 11f with its end portions. The frame springs 11f may, for example, be glued into the end sections.

LIST OF REFERENCE NUMBERS

1

back support

2

chair

11

frame

11e

frame element

11f

frame spring

11v

connecting element

12

tissue

13

frame covering

14

strap

15

strut

16

pursuit Case

Claims (16)

1. Shell-shaped back support (1) for a piece of seating furniture, comprising a frame (11) and a covering (12) stretched over the frame (11), wherein the frame (11) is bent such that the covering (12) is curved in the shape of a saddle, wherein the frame (11) has at least one flexible section, which has at least one coil spring (11f) determining or at least participating in the flexibility of the section, referred to below as a "coil spring frame section",
   characterised in that,
   the frame (11) has several coil spring frame sections and wherein at least two of these coil spring frame sections have different bending stiffness, in that they have coil springs (11f) with different bending stiffness.
2. Back support according to one of the preceding claims,
   characterised in that,
   the coil spring frame section has several coil springs (11f) arranged coaxially with respect to one another.
3. Back support according to one of the preceding claims,
   characterised in that,
   the coil spring frame section has several coil springs (11f) arranged axially one behind the other.
4. Back support according to one of the preceding claims,
   characterised in that,
   the coil spring frame section has an inner frame element, which reaches through the coil spring (11f) or the coil springs.
5. Back support according to claim 4,
   characterised in that,
   the inner frame element has lower bending stiffness than the coil spring (11f) or the coil springs of the coil spring frame section.
6. Back support according to one of the preceding claims,
   characterised in that,
   the frame (11) is formed as a closed or virtually closed ring and has an inner frame on which a coil spring (11f) or several coil springs is or are arranged at least in sections, forming at least one coil spring frame section.
7. Back support according to one of the preceding claims,
   characterised in that,
   the frame (11) is formed as a closed or virtually closed ring, the circumference of which consists exclusively of coil spring frame sections.
8. Back support according to one of the preceding claims,
   characterised in that,
   the frame is formed as a closed or virtually closed frame, the circumference of which consists of frame sections having different bending stiffness, wherein at least one of the frame sections, which has comparably low bending stiffness, is formed as a coil spring frame section.
9. Back support according to one of the preceding claims,
   characterised in that,
   the inner frame element of the coil spring frame section and/or of the inner frame is formed at least in sections as a pipe or rod made from metal or plastic.
10. Back support according to one of the preceding claims,
    characterised in that,
    the inner frame element and/or the inner frame of the frame is formed, at least in sections, as a rod or from twisted metallic wires.
11. Back support according to one of the preceding claims,
    characterised in that,
    the inner frame element of the coil spring frame section and/or the inner frame of the frame has a plastic coating and/or a plastic cover, for example shrink tubing, and/or is injected into preferably flexible plastic.
12. Back support according to one of the preceding claims
    characterised in that,
    the coil spring frame section has a plastic coating and/or a plastic sleeve, preferably shrink tubing, and/or is injected into preferably flexible plastic.
13. Back support according to one of the preceding claims,
    characterised in that,
    coil springs (11f) arranged one behind the other are connected to one another by a connection element (11v) inside the coil spring frame section and/or from two coil spring frame sections that are adjacent to one another and one behind the other.
14. Back support according to claim 13,
    characterised in that,
    the connection element (11v) engages with allocated end sections of the allocated coil springs (11f) and/or the entire length reaches through at least one of the springs to be connected.
15. Back support according to claim 13,
    characterised in that,
    the connection element encompasses the allocated end sections of the coil springs (11f) to be connected and/or the entire length encompasses at least one of the coil springs (11f) to be connected.
16. Back support according to one of claims 13 to 15,
    characterised in that,
    the connection element (11v) has a larger bending stiffness than the coil spring (11f) to be connected.

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