WO2010045745A1

WO2010045745A1 - Backrest for a chair

Info

Publication number: WO2010045745A1
Application number: PCT/CH2008/000436
Authority: WO
Inventors: Egon Bräuning
Original assignee: Vitra Patente Ag
Priority date: 2008-10-21
Filing date: 2008-10-21
Publication date: 2010-04-29
Also published as: EP2337476B1; ES2392577T3; EP2337476A1

Abstract

The chair, for which the backrest (4) is designed, has an underframe (1) sitting on the ground, a mechanism (2) placed onto the underframe (1), and a seat (3) placed onto the mechanism (2). The backrest (4) is fastened to the mechanism (2), wherein the backrest (4) comprises a backrest frame (40), over the inside surface of which a backrest cover (8) is stretched. The backrest frame (40) has a lower base section (42), from which a lateral arm (43) extends upward on either side, wherein the upper ends of the lateral arms are bridged by a cross bar (44), which elastically deforms under the load of a user sitting in the chair in the direction of the force applied by the back of the user resting thereon, but is flexurally rigid against the action of the force perpendicularly from above. The height of the cross bar (44) is multiple times that of the thickness in the cross-section. The backrest cover (8) is provided with seams (80) strengthening the backrest cover (8) over a bordered free space between the base section (42), the lateral arms (43) and the cross bar (44).

Description

Backrest for a chair

Field of application of the invention

The present invention relates to a chair of the type with a floor-mounted underframe, a patch on the base mechanism, a seated on the mechanics seat and attached to the backrest mechanism. The backrest has a backrest frame, which is provided with a padding and a cover. The backrest is articulated on the mechanism and can be pivoted from a basically upright zero position to a rearwardly directed tilt position. The movements of the seat and backrest are synchronized with each other.

State of the art

Special designs for backrests of chairs are e.g. from the patent publications WO 2004/037046 A1 and WO 2007/038879, and have established themselves on the market for comfortable work chairs.

Object of the invention

In relation to the known state of the art, the invention is based on the task of proposing a further improved backrest which supports the user leaning against it ergonomically even more effectively. Another object is to make the connection of the backrest to the chair at the same time easy to install and thus more cost-effective. Finally, there is the task of efficiently designing the backrest to allow optional equipment with different armrests on the chair.

Overview of the invention

The chair for which the backrest is designed has a base placed on the floor, a mechanism attached to the base and a seat fitted to the mechanism. The backrest is attached to the mechanism, the backrest having a backrest frame whose inside surface is made from spanned over a back cover. The backrest frame has a lower

BESTATIGUNGSKOPIE The upper end of the side arms are bridged by a transverse strip which elastically deforms under load from a user sitting in the chair in the direction of the force exerted by the leaning user back force, but against the base part from which extends on either side Force is vertically rigid from above.

Hereinafter, specific embodiments of the invention are defined: The height of the cross bar is in cross section a multiple of the thickness. The back cover is provided with a seam between the base part, the side arms and the cross bar framed with the back cover seams.

In the free space framed by the base section, the side arms and the transverse strip, an elastically deformable tongue protrudes into a lumbar support fastened to the base section.

The stiffness of the lumbar support is adjustable. To adjust the rigidity of the lumbar support is a displaceable in the height position counter bearing.

The upper ends of the side arms have connecting elements, which interact with detent with complementary organs on the cross bar. The base section is provided on the user side as well as the area surrounded by the base section, the side arms and the cross bar with a padding, which is spanned in the free space on both sides of the back cover. The seams go through both sides of the back cover.

The seams are in principle designed as closed ovals and the bottom seam has a recess to allow the retraction of the tongue of the lumbar support.

The backrest frame and the crossbar are made of plastic. The base section has a laterally open cavity, which is pushed open is intended to a fitting of a back strap, which is intended for articulation of the backrest on the mechanism.

The connector has a receptacle that is used to attach an armrest, otherwise it can be closed with a cover. The outer edges of the back cover are fitted to strips, which are clipped into locking holes with their catch organs.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG.

Figure 1A - a chair with the inventive backrest, with upholstery, without cover, without armrests, in an upright zero position, in a perspective front view;

Figure 1 B - the chair according to Figure 1A, in side view;

Figure 2 - the chair according to Figure 1A ₁ with fixed armrests as the first type;

Figure 3A - the chair according to Figure 1A, with adjustable armrests as a second type, in a front perspective view;

Figure 3B - the chair according to Figure 3A, in side view;

Figure 3C - the chair according to Figure 3A, without upholstery in the backrest, in front view;

Figure 3D - the chair according to Figure 3C, with upholstery in the backrest, in front view;

Figure 4 - the chair according to Figure 1A, in partial exploded view, with provided armrests of both types;

Figure 5A - the mechanism of Figure 4 with hinged back straps, in

Perspective view;

Figure 5B - the arrangement according to Figure 5A, in plan view; FIG. 5C - both back yokes from FIG. 4 with axle rod and bearing parts, in explosive view;

FIG. 5D shows the adjustable armrest from FIG. 4 of the arm receptacle in FIG

Approximate backbone;

FIG. 6A shows the backrest from FIG. 4, in a perspective front view; FIG. 6B shows the backrest according to FIG. 6A, without upholstery and covering, with provided lumbai supports of both types, in an exploded view;

FIG. 6C shows the arrangement according to FIG. 6A, in a perspective rear view; FIG. 6D shows the arrangement according to FIG. 6A, with an approximated frame strip, in a top view in perspective; FIG. 6E shows the arrangement according to FIG. 6D, in a normal standing perspective view; Figure 6F, the arrangement according to Figure 6D, with latched frame strip and provided coating strips; Figure 6G a complete backrest, with adjustable Lumbaistütze, padding and cover; and FIG. 6H shows a section through the transverse strip from FIG. 6B on the line A-A.

embodiment

The detailed description of an exemplary embodiment of the backrest according to the invention, its connection to the chair mechanism and two types of armrests to be attached to the backrest will now be described with reference to the accompanying drawings.

The following definition applies to the entire further description. If reference numerals are included in a figure for the purpose of graphic clarity, but are not explained in the directly associated description text, reference is made to their mention in the preceding description of the figures. For the sake of clarity, the repeated designation of components in subsequent figures is usually dispensed with, as far as the drawing clearly shows that they are "recurring" components. Figures 1A to 3D

In the first equipment (see Figures 1A and 1B), the chair resting on a base 1 has no armrests. The known from WO 2007/124609 A2 mechanism 2, which is placed on the base 1, carries the seat 3. By means of two back straps 5, the backrest 4 is hinged to the mechanism 2 and the seat 3. The backrest 4 has a backrest frame 40 in which a lumbar support 48 provided with a padding 49 and a further padding 49 are inserted. On both sides of the flock frame 40 has a cavity 41 for attachment of the back yoke 5, which in turn can be fixed here not provided armrests. Therefore, the receptacle 51 of the back bar 5 is currently closed with a cover 57. In a next configuration (see FIG. 2), a bow-shaped, not height-adjustable armrest 6 of the first type is attached to the receptacle 51. In a further equipment (see Figures 3A to 3D) are mounted on the receptacles 51 instead of not height adjustable armrests 6 of the first type in each case adjustable in height armrests 7 second type.

Figure 4 For the sake of completeness, the main components of the entire chair are given, which next to the base 1 and the mechanism 2 has first the seat 3, which is composed of a seat plate 30, the padding 39 and the outer cover 37. An adjusting lever 31 serves to adjust the depth of the seat 3. The two back straps 5 serve on the one hand to receive the backrest 4 and on the other hand at the same time to fix one of the two types of armrests 6, 7. If you want to do without armrests, the cover 57 comes as a closure on the blank holder 51st

FIGS. 5A to 5D A back yoke 5 is divided into a projection 52 which serves with the bearing parts 57 for connection to the mechanism 2. From the neck 52, the branch 50 extends, which merges into the connecting piece 53. In the connection piece 53 is the outwardly open receptacle 51, while inside a raised guide bar 54 is located. From the branch 50, in each case directed towards one another, stubs 58 which receive an axle rod 55 for articulation on the seat 3. At the connector 53 different screw holes 56 are present. The adjustable armrest 7 has the support 70, on the inside of which the mechanical block 72 is located, which is intended for insertion into the receptacle 51. From the support of the knob 73 protrudes, upon actuation, the armrest 7 can be adjusted in height. The visible under the armrest 7 Löserad 71 is used to unlock in order to adjust the armrest 74 in the horizontal plane can.

FIGS. 6A to 6H

The backrest frame 40 is structured in the base section 42 with the lateral cavities 41 which are surrounded by second latching holes 422. Facing the user, a bearing groove 421 for receiving the plate-shaped counter-bearing 482 extends centrally on the base part 42 and can be varied in the height position by means of an adjusting lever 484 engaging in a toothed wheel 483. At the bottom of the base portion 42 are first detent holes 420. From the two sides of the base portion 42, the two side arms 43 extend, the uppermost conclude with a connection element 430. The open distance between the upper ends of the two side arms 43 is bridged by a transverse strip 44 which has complementary members 440 at its ends, which form a latching plug connection with the connection elements 430. The cross bar 44 has a cross section with a multiple of the height in relation to the thickness. Thus, the cross bar 44 flexes elastically when the user leans against it in the sitting position, however, in principle, no deflection is possible at a load from above.

The plate-shaped lumbar support 47 has in the non-adjustable Ausrührung several equal tongues 471, between which are vertically downwardly running cuts 470. On the side facing the user, the lumbar support 47 is provided with a padding 49, preferably a foam surround. In the assembled state, the lumbar support 47 is placed on the base part 42 of the back frame 40, wherein the tongues 471 protrude beyond the base portion 42 into the space between the side arms 43. In the adjustable Ausrührung the also plate-shaped lumbar support 48 has a lying in the middle wide tongue 481, which projects beyond the outer tongues 481, which are divided by cuts 480. This lumbar support 48 has a padding on the user side 49. In the assembled state, the lumbar support 48 is positively on the base portion 42, wherein the counter-bearing 482 is adjustable in height and thus touches the back at various positions on the wide tongue 481, what their the user changes effective stiffness. Regardless of which of the lumbar supports 47, 48 one uses, the free space remaining above in the backrest frame 40 is lined with inlaid padding, for example with a foam plate.

In the free space between the side arms 43 and above the base portion 42, the tongues 481 of the adjustable lumbar support 48 protrude, the abutment 482 resting against the middle tongue 481. On the back of the base portion 42 screw holes 423 are arranged around the knob 73 around to fix the lumbar support 48 by means of screws. For fixing the edges of the back cover 8 a cup-shaped frame strip 45 is provided, from which lugs 450 rise, which are provided for latching in the first detent holes 420, wherein the lower edge of the on the user side lying back cover 8 outside pulled over the frame strip 45 and eg is glued. The lower edge of the lying on the back side back cover 8 is reinforced with a terminal block, not shown, and hooked into the longitudinal groove 424. After snapping the frame strip 45 is covered by this hanging in the longitudinal groove 424 terminal block and thereby fixed.

For a clean completion of the outer edges of the back cover 8 around the cavities 41 around a coating strip 46 with protruding lugs 460 attached to the outer edges, eg sewn. This one hits inwardly into the cavities 41 and snaps the noses 460 in the second locking holes 422 a. In this prepared condition, the complete backrest 4 on the two attached to the mechanism 2 back strap 5, namely pushed their fittings 53, which retract into the downwardly open cavities 41. In the positioned state, the back strap 5 is screwed by its connecting piece 53 to the base section 42. In the space between the side arms 43 and the base portion 43 are provided on the back cover 8 by the spanned on both sides of the backrest 4 back cover 8, including the embedded therein padding 49, continuous seams 80. When using an adjustable lumbar support 48, the lowermost seam 80 made in the closed oval has a recess 81 so that the towering middle tongue 481 of the lumbar support 48 can protrude into this pocket-shaped seam 80.

With this structural design of the backrest 4, on the one hand, a thin and lightweight design succeeds, on the other hand, excellent ergonomic properties. A reclining user flexes the cross bar 44 somewhat outwards by its weight, so that the upper corner areas of the backrest 4 move relatively towards the shoulder portion of the user and thus provide excellent support. At the same time the user sinks softly cushioned with his back in the backrest 4, thereby experiencing a comfortable, supported curvature, with the result that his head posture almost automatically results in a horizontal direction of view in principle.

Claims

Patent claims

A seat back (4) for a chair comprising: a) a base (1) placed on the floor; b) a mechanism (2) placed on the underframe (1); c) a seat (3) placed on the mechanism (2); and d) a backrest (4) fastened to the mechanism (2), which has a backrest frame (40) whose inner surface is covered by a back cover (8), characterized in that e) the back frame (40) consists of a lower base part (42), of which a side arm (43) extends upwards on both sides and the upper one

Ends of the side arms (43) by a transverse bar (44) are bridged, which is elastically deformed under load by a user sitting in the chair in the direction of the force applied by the leaning user back force, but is resistant to bending vertically from above.

2. Backrest (4) according to claim 1, characterized in that a) the height of the transverse strip (44) in cross-section is a multiple of the thickness; and b) the back cover (8) is provided with seams (80) which consolidate the back cover (8) via a free space bordered between the base section (42), the side arms (43) and the transverse strip (44).

3. backrest (4) according to at least one of claims 1 and 2, characterized in that in the of the base portion (42), the side arms (43) and the transverse strip (44) bordered free space an elastically deformable tongue (471, 481) of a base part (42) fixed lumbar support (47,48) protrudes.

4. backrest (4) according to at least one of claims 1 to 3, characterized in that a) the rigidity of the lumbar support (48) is adjustable; and b) for adjusting the rigidity of the lumbar support (48) a displaceable in the height position abutment (482) is used.

5. backrest (4) according to at least one of claims 1 to 4, characterized in that a) have the upper ends of the side arms (43) connecting elements (430) which latchingly cooperate with complementary members (440) on the transverse bar (44); b) the base part (42) on the user side and of the base part (42), the side arms (43) and the transverse strip (44) framed free space is provided with a padding (49) in the free space on both sides of the back cover (8) is overstretched; and c) passing through the seams (80) through both sides of the back cover (8).

6. backrest (4) according to at least one of claims 1 to 5, characterized in that the seams (80) are designed in principle as closed ovals and the bottom seam (80) has a recess (81) to retract the tongue (481) lumbar support (48).

7. Backrest (4) according to at least one of claims 1 to 6, characterized in that a) the back frame (40) and the transverse strip (44) consist of plastic; and b) the base part (42) each laterally has a downwardly open cavity (41) for pushing on a connecting piece (53) of a back strap

(5) is determined, which is intended for articulation of the backrest (4) on the mechanism (2).

8. Backrest (4) according to at least one of claims 1 to 7, characterized in that a) the connecting piece (53) has a receptacle (51) which serves for attaching an armrest (6,7), otherwise with a cover (57); and the outer edges of the back cover (8) on strips (45,46) are taken, which are clipped with their locking members (450,460) in locking holes (420,422).