EP0419714B1 - Backrest with a lumbosacral support adjustable in height - Google Patents

Abstract

In a padded backrest with a lumbosacral support which can be adjusted in height and which comprises a backrest cushion (3) on a cushion panel (2) and, arranged between these, a lumbosacral support part (1), a simplified construction, together with improved function and increased seating comfort, is achieved by virtue of the fact that the lumbosacral support part (1) can be displaced in the vertical direction relative to the backrest cushion (3) and the cushion panel (2). <IMAGE>

Description

TECHNICAL AREA

• (a) eine Polsterplatte;
• (b) ein auf der Polsterplatte aufliegendes, einstückiges Rückenlehnenpolster; und
• (c) ein Lordosestützteil, welches eine Vorwölbung des Rückenlehnenpolsters bewirkt und relativ zum Rückenlehnenpolster und zur Polsterplatte in vertikaler Richtung verschiebbar ist;

Eine solche Rückenlehne ist beispielsweise aus der US-A 4,502,728 bekannt.The invention relates to the field of seating. It relates in particular to a padded backrest with a height-adjustable lumbar support, comprising

• (a) a cushion plate;
• (b) a one-piece backrest cushion resting on the cushion plate; and
• (c) a lumbar support part which causes the backrest cushion to bulge and can be displaced in the vertical direction relative to the backrest cushion and the cushion plate;

Such a backrest is known for example from US-A 4,502,728.

STATE OF THE ART

For some time now, work seating and especially office chairs have been able to adjust the backrest even in the vertical direction. This is supposed to necessary balance to the different body or. Hull sizes can be achieved by the owner.

The aim of such adjustment devices is that precise support in the area of the lower lumbar vertebrae (lumbar lordosis area) of the respective user is achieved with a cushion which is shaped in accordance with the shape of the spine. Correct support of the back is an essential prerequisite for sitting longer periods without symptoms.

It must be ensured that the backrest cannot move unintentionally while sitting. For this purpose, detents are usually provided, which - when unlocked - release the entire backrest so that it can be moved up and down. It goes without saying that appropriately designed guides must be available if a reliable, smooth adjustment is to be achieved. However, the appearance of the chair also changes apparently depending on the set backrest height.

A large number of work chairs - especially those according to type A of DIN 4551 - work using this method. Due to the guidance and the required locking of the backrest, the construction effort of the mostly simple chairs increases considerably, especially if the components are designed to be durable and robust.

It can also be seen as a disadvantage that there must be a gap between the backrest and the seat, which leads to a less harmonious appearance of the chair when the backrest is set high.

The entire backrest also has to be moved, which is often made more difficult by the tilting effects in the guide, in addition to its own weight. In most versions of such backrests, actuation with two hands remains unavoidable: while one hand operates the lock, the other positions the backrest in the desired position. Constructions can also be found in which an operation while sitting is impossible due to the difficult to reach or difficult operating elements.

Generally, it has to be seen as a disadvantage that office work chairs and armchairs corresponding to types B, C and D according to DIN 4551 have so far had to do without height-adjustable lordosis support. Type D armchairs try to compensate for this disadvantage by appropriately proportioned padding. However, this is only possible incompletely, since the adjustment ranges of a height-adjustable backrest cannot be sufficiently understood and the anatomical conditions of the respective user are not taken into account. With chairs and armchairs of type B and C, the users are physiologically less well supported, the more their trunk size deviates from the statistical mean.

In the past, various attempts have now been made to make the profile of a backrest adjustable in a way. For example, DE-A1 36 34 500 contains various proposals for a backrest which is vertically adjustable, inter alia, in the longitudinal cross section.

According to these proposals, either the backrest as a whole is adjusted in height (FIG. 2) or a lower backrest part is displaced in relation to an upper backrest part (FIG. 4, 5), or the rear support shell is designed to be flexible in a special way (FIG. 7).

In the first case, the movement of the entire backrest - as already mentioned above - results in an uncomfortable and cumbersome adjustment.

In the second case, a joint in the upholstery must be added. All-over support of the back is interrupted. This leads to additional pressure points in the transition area between the fixed and movable backrest part.

Finally, in the third case, the carrier shell has to be made in several pieces in a complex manner, which on the one hand impairs the stability of the backrest and on the other hand limits the adjustment range.

Another possibility of adjusting a longitudinal backrest profile is described in WO-A1 85/00736; Here vertical slats - comparable to a slatted frame in a bed - are deformed by a height-adjustable roller.

Disadvantages of this solution can be seen in the fact that the slat structure is very complex and the bulging of the upholstery is not limited to a local area because of the slats, but extends over the entire backrest. In addition, it is difficult with this type of height adjustment to additionally provide an adjustment of the protrusion in the horizontal direction.

A portable seat with a height-adjustable "lumbar support" 15 is known from US Pat. No. 4,502,728 mentioned at the beginning, in which a device 70 slidably arranged on resilient rails presses on a continuous resilient cushion plate 42 from behind. Since the entire upholstery plate is deformed in this solution, locally limited, pronounced protrusions cannot be achieved in this way.

GB-A 2 107 576 shows a backrest with a height-adjustable "lumbar support" in the form of a "pad" 18, which is slidably mounted in side parts 17, 18 of the backrest and directly under the back cushion 34 - separated by a film 35 - slides along. A cushion plate lying under the cushion is not provided in this solution, so that the cushion cannot be given a solid shape overall.

GB-A 2 112 277 finally discloses a backrest with height and curvature adjustable "lumbar support" in the form of a rotatable and displaceable tube 25 which acts on a fixed "padding". However, no detailed statements are made about the structure of the backrest itself.

For the sake of completeness, reference is also made to the publications US Pat. No. 3,948,558, US Pat. No. 4,725,095 and GB Pat. No. 2 196 530, which all relate to "lumbar support" without height adjustment.

PRESENTATION OF THE INVENTION

The object of the present invention is now to provide a height-adjustable backrest which avoids the disadvantages of previous solutions described above and is characterized in particular by body-adjustable adjustability with simplified handling and reduced construction costs. In addition, it should be possible to change the degree of the bulging in the horizontal direction in a simple manner in addition to the lumbar height adjustment.

• die vertikale Verstellmöglichkeit des Lendenbausch-Bereiches der Rückenlehne für Büroarbeitssessel der Bauart D nach DIN 4551 auf einen mindestens ebenso grossen Bereich auszulegen, wie er für Arbeitsstühle nach Bauart A in DIN 4551 ratsam erscheint;
• die Verstellung zu erlauben, ohne dass sich der Benutzer aus dem Stuhl erheben oder weit von der Lehne abrücken muss;
• eine weitgehende Reduzierung des Bauaufwandes und des Gewichtes zu erreichen;
• die erforderlichen baulichen Massnahmen zum Vorteil für den visuellen Gesamteindruck des Stuhles zu realisieren; und
• im Rahmen eines Baukastensystems eine vertikale oder horizontale Profiländerung getrennt voneinander oder kombiniert in einem geschlossenen System zu verwirklichen.

The aim is in detail

• the vertical adjustment of the lumbar area of the backrest for office armchairs of type D in accordance with DIN 4551 should be designed to be at least as large as it appears advisable for type A work chairs in DIN 4551;
• allow adjustment without the user having to rise from the chair or move far from the backrest;
• to achieve a substantial reduction in construction costs and weight;
• to implement the necessary structural measures to the advantage for the visual overall impression of the chair; and
• as part of a modular system, a vertical or horizontal profile change separately or to be combined in a closed system.

• (d) die Polsterplatte im Lordosenstützbereich eine Aussparung aufweist; und
• (e) das Lordosestützteil im Bereich der Aussparung angeordnet ist und durch die Aussparung hindurch auf das Rückenlehnenpolster drückt.

The task is solved in a backrest of the type mentioned in that

• (d) the cushion plate has a recess in the lumbar support area; and
• (e) the lordosis support part is arranged in the region of the recess and presses through the recess onto the backrest cushion.

The essence of the invention is therefore that a compact segment placed on the back of the upholstery and integrated into the backrest, which presses directly onto the backrest upholstery through a recess in the upholstery plate, can be moved up and down separately by means of an adjusting member.

The segment is designed in such a way that, in the middle position of its adjustment range, it complements the backrest upholstery to a shape aimed at a medium-sized person; From this standard setting, it can now be adapted to large and small owners by moving it up or down.

The zone of the maximum protrusion on the front of the cushion thus shifts up or down; This enables a wide range of adaptations to anatomical conditions in humans under ergonomic criteria.

It is advantageous that the appearance is a priori less defined than for chairs with one overall height-adjustable backrest. This increases the creative freedom, which can be implemented in a more harmonious structure of the chair.

The adjustment is made easier for the user by the fact that the entire backrest no longer has to be moved up and down, but rather only a single part with a comparatively low weight is moved under the cushion cover.

A preferred development of the invention is characterized in that additional means are provided for changing the bulging of the backrest cushion by moving the lumbar support part back and forth.

Here, the lordosis support part can either be coupled with its linear vertical movement or independently of it perform the additional horizontal movement.

The height adjustability takes into account individual body size and trunk proportions and therefore has a clear priority. According to occupational medicine recommendations, the height adjustment should cover a range of approx. 70 mm. The additional adjustability of the protrusion in the horizontal direction, on the other hand, proves to be useful for people whose spine profile in the lumbar region deviates from a normal shape (curved further forward or flatter).

Other preferred developments and exemplary embodiments of the invention result from the subclaims.

BRIEF DESCRIPTION OF THE DRAWING

Fig.1

den Aufbau der Rückenlehne (von vorne betrachtet; ohne Rückenlehnenpolster) für eine reine Höhenverstellung des Lordosenstützbereiches gemäss einem ersten bevorzugten Ausführungsbeispiel der Erfindung;

Fig.2

die Rückenlehne gemäss Fig.1 im Längsschnitt;

Fig.3a,b

den Verstellbereich bei einer Rückenlehne gemäss Fig.2;

Fig.4

in der perspektivischen Rückansicht eine Rückenlehne mit getrennter Vertikal- und Horizontalverstellung des Lordosestützteils gemäss einer ersten bevorzugten Weiterbildung der Erfindung; und

Fig.5

in der perspektivischen Rückansicht eine Rückenlehne mit getrennter Vertikal- und Horizontalverstellung des Lordosestützteils gemäss einer zweiten bevorzugten Weiterbildung der Erfindung.

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the drawing. Show it

Fig. 1

the structure of the backrest (viewed from the front; without backrest cushion) for a pure height adjustment of the lumbar support area according to a first preferred embodiment of the invention;

Fig. 2

the backrest according to Figure 1 in longitudinal section;

3a, b

the adjustment range for a backrest according to Figure 2;

Fig. 4

in the perspective rear view a backrest with separate vertical and horizontal adjustment of the lordosis support part according to a first preferred development of the invention; and

Fig. 5

in the perspective rear view a backrest with separate vertical and horizontal adjustment of the lordosis support part according to a second preferred development of the invention.

WAYS OF CARRYING OUT THE INVENTION

1 shows in the front view and with the backrest cushion removed, FIG. 2 in longitudinal section (with cushion) the structure of a backrest with a height-adjustable lumbar support area according to a preferred embodiment of the invention.

An example of conventionally designed upholstery, consisting of a one-piece cushion plate 2 and a one-piece backrest cushion 3 (which comprises a foam pad and a cover fabric), has a recess 2a in the cushion plate 2 on the back, which has a curved, one-piece lordosis support part 1 with the takes up the necessary freedom of movement.

The lumbar support part 1 presses through the recess 2a directly onto the backrest cushion 3. In order to minimize the friction and prevent wear on the back of the backrest cushion 3, a tensioned release film 5 is preferably provided between the cushion and the lordosis support part 1, which e.g. can be glued to the backrest cushion 3 on the foam side.

Attached flags 11, which are part of the cushion plate 2 and can be guided in the lordosis support part 1, ensure that the owner feels an even pressure distribution on the cushion, even when the lordosis support part 1 is in the lowest position. The flags 11 bridge the changing gap between the lordosis support part 1 and the cushion plate 2. If the lordosis support part 1 is in the highest position, those in the lower region of the backrest are already small Pressure forces are transmitted through the tabs 11 projecting downwards.

Controlled movement of the lordosis support part 1 is made possible via suitable guideways 7 (FIG. 2), for example ribs, and leaning forces of the seated person are derived into a support structure 9, which in this exemplary embodiment supports the backrest.

In order to achieve smooth adjustment, an adjusting element in the form of a lever arm 6 engages the lordosis support part 1; the lever arm 6 is mounted in a pivot point 8 which is fixed to the cushion plate 2 laterally from the recess 2a and emerges on the other side from a covering 4 from or under the cushion. It is operated there by means of a key 10. For locking, a locking element 23 is provided, which is arranged displaceably on the lever arm 6 and is pressed by means of a spring 24 against a corresponding locking bar 22 in the casing 4.

A suitable design of the lever ratios between the pivot point, the point of application on the lordosis support part 1 and the button 10 ensures that the button 10 can be actuated smoothly. The adjustment range achieved, characterized by the upper and lower positions of the lordosis support part 1, is shown in FIGS. 3a, b.

An additional horizontal adjustment of the movable lordosis support part 1 can take place in a further embodiment of the backrest according to the invention such that the base on which the wedge-shaped lordosis support part 1 is guided is changed horizontally (FIG. 4).

In this case, the adjustment can be maintained with the lever arm 6 described, the driver on the lordosis support part 1 compensating for the horizontal movement that occurs either by a link-like configuration or even more advantageously by its inherent elasticity in the horizontal direction (e.g. in the case of a spring band steel version).

Simplified, cranks 12 in the form of bent wire parts can be used here. Acting as a parallelogram, they are rotatably supported on the one hand by means of crank bearings 20 on the cushion plate 2 or the supporting structure 9. On the other hand, they engage in guides 15 on the lordosis support part 1 via rails 15a.

About an actuating lever 6a, which is rotatably mounted in a fixed bearing 13, the cranks 12 are moved up and down via a coupling part 14, which results in the desired, exactly parallel, horizontal movement for the guides 15 and thus for the wedge.

A further simplification was represented by a single, centrally arranged crank which is acted upon directly by the actuating lever 6a. A disturbing tilting of the lordosis support part 1 is effectively prevented by the flags 11 of the cushion plate 2, which penetrate the lordosis support part 1.

According to a further preferred embodiment (FIG. 5), an additional horizontal adjustment can take place in such a way that the horizontal movement is initiated via a handwheel 18 and a shaft 17 which is mounted on the supporting structure 9 by means of shaft bearings 21. On the shaft 17 are preferably polygonal cams 16 with from Cam surface to cam surface arranged increasing center distance, which determine the distance between shaft 17 and lumbar support part 1 and thus ensure the desired adjustability of the protrusion. Rails 19 are provided for vertical guidance. Here, too, the flags 11 stabilize the lordosis support part 1.

In both cases, the lordosis support part 1 can be acted upon directly on the rear side if the guides 15 on the one hand and the rails 19 on the other hand are made deeper than the horizontal adjustment path.

In the foregoing, the invention has been explained on the basis of special exemplary embodiments. Other embodiments within the scope of the invention are also possible.

It is thus conceivable that the lumbar support part 1 lies movably within the structural unit comprising the backrest cushion 3 and the cushion plate 2, but the adjustment element acts outside and only on the back of the lordosis support part 1.

The backrest cladding can also be self-supporting; the supporting structure 9 can therefore possibly be omitted, i.e. be an integral part of the backrest cover.

The height adjustment can also be done by a roller-shaped button or a slide on the outside of the panel 4; A structural simplification would then result from the elimination of the lever arm 6 and the pivot point 8.

The inclination of the guideway 7 can also be varied in such a way that there is a correlation between a smaller seat depth at a low seat or a greater seat depth when the lordosis support part 1 is set high.

Finally, the slidable part can also be designed as a padded, separate part.

Claims (9)

1. Padded backrest having a vertically adjustable lumbar lordosis support, comprising

   (a) a padded board (2);

   (b) a one-piece backrest cushion (3) resting on the padded board (2); and

   (c) a lordosis support part (1) which causes a forward arching of the backrest cushion (3) and which is displaceable in the vertical direction relative to the backrest cushion (3) and to the padded board (2);

   characterised in that

   (d) the padded board (2) has a clearance (2a) in the lordosis support region; and

   (e) the lordosis support part (1) is arranged in the region of the clearance (2a) and presses through the clearance (2a) onto the backrest cushion (3).
2. Backrest according to Claim 1, characterised in that the padded board (2) and the lordosis support part (1) are each made in one piece.
3. Backrest according to Claim 2, characterised in that

   (a) the padded board (2) is fastened at the rear to a carrier structure (9);

   (b) the carrier structure (9) has means for the vertical guidance of the lordosis support part (1); and

   (c) an adjusting element for the vertical displacement of the lordosis support part (1) is arranged on the padded board (2).
4. Backrest according to Claim 3, characterised in that

   (a) the adjusting element comprises a lever arm (6);

   (b) the lever arm (6) is rotatable about a centre of rotation (8) arranged laterally next to the clearance (2a) and fixed to the padded board (2);

   (c) the lever arm (6) extends approximately horizontally; and

   (d) engages on the lordosis support part (1).
5. Backrest according to Claim 3, characterised in that additional means for changing the forward arching of the backrest cushion (3) by setting the lordosis support part (1) forwards and backwards are provided.
6. Backrest according to Claim 5, characterised in that

   (a) the means for changing the forward arching comprise at least one crank (12);

   (b) the at least one crank (12), on the one hand, is mounted rotatably in crank bearings (20) on the carrier structure (9) or padded board (2); and

   (c) on the other hand, engages on the lordosis support part (1) via a rail (15a) running in a guide (15).
7. Backrest according to Claim 5, characterised in that

   (a) the means for changing the forward arching comprise a shaft (17);

   (b) the shaft (17) is mounted rotatably in shaft bearings (21) on the carrier structure (9); and

   (c) arranged on the shaft are polygonal cams (16) which determine the distance between the lordosis support part (1) and the shaft (17).
8. Backrest according to one of Claims 1 to 7, characterised in that, to achieve a more uniform pressure distribution on the backrest cushion (3),

   (a) vertically extending tabs (11) are attached to the padded board (2);

   (b) the tabs (11) project into the clearance (2a); and

   (c) are guided in the lordosis support part (1).
9. Backrest according to one of Claims 1 to 8, characterised in that, to reduce the friction, a separating foil (5) is arranged between the backrest cushion (3) and the lordosis support part (1) and is adhesively bonded to the backrest cushion (3).

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