EP0585753A1 - Chair with height-adjustable backrest - Google Patents

Abstract

A chair (10) has a guide arrangement (14) which guides a height-adjustable part (23) serving to fix its backrest (25). Located in the central region of the guide arrangement (14) is a guide opening (28) for longitudinal guidance of a force application member (34) which is connected to the height-adjustable part (23) and acts on the one toggle lever arrangement (44). The latter is assigned an actuating member (48) which can be actuated by the user of the chair (10) for the purpose of adjusting the toggle lever arrangement (44). <IMAGE>

Description

The invention relates to a chair with a height-adjustable backrest.

Office chairs with a height-adjustable backrest are known. A tube is usually attached to the frame of the chair so that its angular position can be changed relative to the seat frame, and that a height adjustment of this tube is also possible, e.g. by clamping at different heights. The actual backrest is then attached to the upper end of the tube.

Such chairs are quite practical and ergonomic, but their setting is not very sensible and it is quite time-consuming. It can often be observed that the height of the backrest is not optimally adjusted for the user concerned, probably because the user of the chair does not know how to do it, or because the possibility exists, or because the adjustment is too laborious for him / her . This promotes the occurrence of postural damage in the workplace.

An object of the invention is to provide a new chair with an adjustable backrest.

According to the invention, this object is achieved by the measures specified in claim 1. The toggle lever arrangement allows - if designed accordingly - a stepless height adjustment of the backrest, whereby it acts on the force application member that is longitudinally guided in the guide recess and, via this, on the height-adjustable part, which in turn is provided with a guide arrangement, so that the forces that are used when it is height-adjustable Act part, can be safely caught. The back upholstery can then be attached to the height-adjustable part, for example a ribbed molded part made of plastic, so that the height of the entire backrest of a secretary's chair can be adjusted with such a height adjustment can be adjusted, as is very important, for example, for long work on the typewriter. However, the invention in particular also enables a very individual adaptation to the body size in the case of types of office chairs, where such adjustments have not previously been considered, for example in so-called executive chairs.

A particularly advantageous embodiment of the invention results from the subject matter of claim 2. This enables a very compact design, and a basic shape of a chair frame designed in this way can be equipped with different upholstery as desired, so that the basic shape - including the height adjustment - result in sufficient quantities.

A further embodiment of the invention is the subject of claim 3. Such guide grooves enable lateral guidance and also guidance against the pressure exerted by the user on the backrest and which can assume considerable values, e.g. with isometric exercises of the user.

An additional guidance, especially in the central area, results from the features of claim 4.

There are naturally various design options for the toggle lever arrangement. Preferred possibilities are the subject of claims 5 and 6. It is particularly advantageous to proceed in such a way that the actuator for the threaded shaft of the toggle lever arrangement is arranged approximately at the foot of the backrest and next to it so that it can be easily reached by the seated user. This enables the backrest to be adjusted in height while the user is sitting on the chair and can immediately try out the correct setting. Such a type of adjustment is ergonomically particularly valuable, and it enables the use of such chairs also in so-called part-time workplaces where a first person works in the morning and a second person in the afternoon. Both can adapt the chair to their personal height and body shape without any difficulty and with a minimum of time and thus achieve an optimal work performance in their short working hours.

A particular advantage of a toggle lever arrangement with a threaded shaft is the self-locking of the height adjustment, i.e. the back part remains in any position once set without an additional brake arrangement. This makes the arrangement for height adjustment very simple and is subject to practically no wear.

A very preferred further development is the subject of claim 8. Adjustable lumbar supports are known, some of which are very complicated, since they themselves must have some form of height adjustment in the case of a height-adjustable backrest, because nothing is more unpleasant than a lumbar support in the wrong place. By means of the invention, the lumbar support can now be brought to the exactly right place, by means of the height adjustment, where it exerts the desired tactile stimulus on the right place on the back. It is therefore also possible to design such a lumbar support very simply and nevertheless effectively, as stated in claims 9 to 15.

Fig. 1

eine raumbildliche Darstellung einer bevorzugten Ausführungsform eines erfindungsgemäßen Stuhls mit einer höhenverstellbaren Rückenlehne,

Fig. 2

eine Draufsicht von vorne auf die Mechanik zur Höhenverstellung; die Stellung der Fig. 1 ist in Fig. 2 mit gestrichelten Linien dargestellt,

Fig. 3

eine Draufsicht von oben, gesehen in Richtung des Pfeiles III der Fig. 2,

Fig 4

einen Längsschnitt, gesehen in Richtung der Pfeile IV-IV der Fig. 3,

Fig. 5

eine raumbildliche Darstellung einer bevorzugten Variante mit einer einstellbaren Lumbalstütze, und

Fig. 6 und 7

schematische, teilweise im Schnitt dargestellte Darstellungen zur Erläuterung der Wirkungsweise der Fig. 5.

Further details and advantageous developments of the invention result from the exemplary embodiments described below and shown in the drawing, which are in no way to be understood as a restriction of the invention, and from the remaining subclaims.
It shows:

Fig. 1

3 shows a spatial representation of a preferred embodiment of a chair according to the invention with a height-adjustable backrest,

Fig. 2

a plan view from the front of the mechanism for height adjustment; the position of Fig. 1 is shown in Fig. 2 with dashed lines,

Fig. 3

a plan view from above, seen in the direction of arrow III of FIG. 2,

Fig. 4

3 shows a longitudinal section, viewed in the direction of the arrows IV-IV in FIG. 3,

Fig. 5

a spatial representation of a preferred variant with an adjustable lumbar support, and

6 and 7

5 shows schematic representations, partly in section, to explain the mode of operation of FIG. 5.

In the following description, the terms left and right refer to the respective figure. The terms "front" and "back" refer to the normal use of a chair, e.g. "He leaned back" or: "She was sitting on the front edge of the chair."

Fig. 1 shows schematically parts of the seat frame 11 of a chair 10, usually an office chair. The seat frame 11, which could also be referred to here as a backrest support, has at the bottom a support plate 12 which, in the finished state, carries a seat cushion or a seat shell indicated at 13 in FIG. 5. A chair support (not shown) is attached to the underside of the support plate 12 and is usually provided with castors in an office chair.

At the back of the carrier plate 12 is a back part 14, which serves as a guide arrangement for the height adjustment. As shown, this can be rigidly connected to the carrier plate 12. However, its inclination relative to the support plate 12 can also be variable, in the form of a so-called adjustable back inclination. Since it is not important for the explanation of the invention whether the inclination of the back part 14 is adjustable or not, this possibility is not shown. However, it is expressly pointed out that an inclination adjustment of the back part 14 is within the scope of the invention and in connection with the invention is readily possible and can also be advantageous.

It is also possible, for example, in the arrangement shown, in which the support plate 11 and the back part 14 are rigidly connected to one another (such an arrangement is sometimes also referred to as a back bar), the entirety of the support plate 11 and the back part 14 to pivot about a horizontal pivot axis S, as is only indicated schematically in FIG. 1. This pivot axis S is articulated on the so-called mechanics of the chair (not shown).

The back part 14 has the basic shape of a plate 14 '. On both edges 15 and 16 of this plate 14 'there are flange-like spreads 17 (left) and 18 (right), respectively, and these are bent inwards on the back and form guide grooves 19 (left) and 20 (right) there.

A height-adjustable part 23 is guided in the height direction in the guide grooves 19, 20, e.g. a plate or a plate-like part made of a dimensionally stable plastic, which is provided with suitable reinforcing ribs (not shown) and carries the actual backrest 25, which is only indicated in the drawing with dashed lines and usually has an upholstery. If the part 23 is moved upwards in the direction of the arrow 24, the backrest 25 also moves upwards, and vice versa.

In the middle of the plate 14 'of the back part 14 there is an approximately rectangular guide recess 28. If the chair 10 stands on a horizontal surface, the lateral boundaries 29, 30 of the guide recess 28 run vertically in the plan view according to FIG. 2 and they run parallel to each other. Between these lateral boundaries 29, 30, a force application member 34 is guided so as to be longitudinally displaceable. Together with the height-adjustable part 23, this forms two longitudinal grooves 35, 36 (FIG. 3) into which the lateral boundaries 29, 30 engage, as shown in FIG. 3.

On the force application member 34 and on the height-adjustable part 23, two levers 41 (left) and 42 (right), which belong to a toggle lever arrangement 44, engage via a bolt 40. The levers 41, 42 extend in the manner shown from the bolt 40 obliquely downward to an associated nut 45 or 46. The left lever 41 is thus rotatably articulated on the nut 45 and on the force application element 34, and the right lever 42 is rotatably articulated on the nut 46 and on the force application element 34.

The nut 45 has a left-hand thread and is guided on a corresponding left-hand thread 45 'of a shaft 47. The nut 46 has a right-hand thread and is guided on a corresponding right-hand thread 46 'of the shaft 47.

If the shaft 47 is rotated with the aid of the actuating button 48, which is indicated in FIG. 1 by the arrow 50, the nut 45 is shifted to the right and the nut 46 to the left, for example, so that these two nuts come closer to one another and thereby move the force application member 34, the height-adjustable part 23 and the backrest 25 in the upward direction. - When the knob 48 is turned in the opposite direction, the nuts 45, 46 move away from one another and the backrest 25 is correspondingly moved downwards. It is clear that both nuts 45, 46 are secured against rotation by the levers 41 and 42, respectively, and that the height adjustment is infinitely possible and self-locking.

The shaft 47 is mounted in the widenings 17, 18 of the back part 14 and is also secured there against longitudinal displacement by at least one axial bearing 50. Depending on the design of the toggle lever arrangement 44, this can be varied in a known manner. In some cases, for example, only one of the two levers 41 or 42 may suffice, since the force application member 34 can deliver the required counterforce due to its longitudinal guidance in the recess 28. For example, the lever 42 could also be omitted at the point shown and instead extend downward from the nut 45 to a stationary articulation point on a lower extension of the back part 14. In this case, the shaft 47 would have to be in a corresponding elongated hole guide in the side parts 17, 18 be vertically movable. There are considerable variations here, but the solution shown is preferred as the currently optimal one.

2 and 4 show the maximum adjustment stroke H, which results when the nuts 45, 46 between their position maximum distance, which are designated in FIG. 2 with A and B and correspond to the lowest position of the backrest 25, and their Position minimum distance, which are designated in Fig. 2 with A 'and B' and correspond to the highest position of the backrest 25, are adjusted. Any intermediate positions are possible within this stroke H.

As can be seen from FIG. 4, the force application member 34 can be formed in one piece with the height-adjustable part 23. However, these parts can also be formed separately and only firmly connected to one another during assembly.

The mode of operation of the height adjustment already results from the above description, i.e. by turning the knob 48 (arrow 50), the force application member 34 and the height-adjustable part 23 firmly connected to it can be raised or lowered as desired. Since the toggle lever arrangement 44 is self-locking in the form shown, the backrest 25 remains in the height position once set.

It appears very advantageous that - in contrast to known height adjustments of office chairs - this adjustment is possible in the user's sitting position, because the actuation button 48 is located on the foot part of the backrest 25 and in the grip area of the user, i.e. the latter can correctly adjust the height of the backrest 25 without leaving the sitting position.

This also enables further training, as shown in FIGS. 5 to 7. This development can also have independent significance, but is preferably used in conjunction with the height adjustment according to FIGS. 1 to 4, or another height adjustment.

The upholstery 25 of the backrest contains a lumbar organ in the area 55, the so-called lumbar support, sometimes also referred to as a lumbar pad. It is actuated by an elongated, horizontally arranged hose 56. This is in a kind of cage 57. The latter has a rigid rear wall part 54 made of plastic, on which two hinge projections 58, 59 are provided at the top, between which, as shown, an upper rod 60 is articulated. From this rod 60, at a distance from one another, a plurality (here: five) of flexible spring plates 63 extend downward to a lower rod 65.

The lower rod 65 is displaceably and rotatably guided in a left slot section 66 and a right slot section 67. The two elongated hole sections 66, 67 extend essentially in the vertical direction.

The hose 56 lies between the flexible spring plates 63 and the rear wall part 54. The flexible spring plates 63 preferably have a substantially straight shape in the relaxed state, as shown in FIG. they strive to force the air out of the hose 56. The elongated hole sections 66, 67 enable this straight shape, cf. Fig. 6.

The inflatable tube 56 is connected via a line 70 to a vent valve 72 and to a small air pump 74, e.g. in the form of a rubber bellows. By operating the air pump 74, as can be readily understood, air can be pumped into the hose 56 so that it takes on the shape shown in FIG. 7 and the spring plates 63 are bent convexly forward. If the vent valve 72 is actuated, the spring lamellas 63 press the air out of the hose 56 again, i.e. the arrangement is self-venting.

When the hose 56 is inflated, the upholstery of the backrest 25 moves in the lumbar region from the rest position 55 'shown in FIG. 6. forward into the expanded position 55. The size of the lumbar stroke H _L (FIG. 7) can be adjusted by the user by means of the pump 74 and the valve 72.

Now there is nothing more uncomfortable for the user of a chair than a lumbar support in the wrong place, i.e. Depending on the size and shape of the user, the point of the lumbar support must be higher or lower.

The invention enables adjustment of the lumbar organ 55 in a wide, three-dimensional range: the lumbar organ 55 can be adjusted within the entire vertical range H (FIG. 2) by means of the height adjustment, and within the entire range by means of the pump 74 and the valve 72 horizontal area H _L (Fig. 7). As a result, each user can approach his or her personal optimum setting over time, a major advantage of the invention. On the other hand, it was necessary in the prior art to provide a large number of such flexible hoses one above the other on the backrest for the purpose of lumbar support, compare, for example, DE 34 43 935 A1, which is undoubtedly far more complex and nevertheless does not permit optimal adjustment.

It should also be emphasized here that the adjustment of the stroke H _{L is possible} in the user's sitting position, since both the pump 74 and the valve 72 are within the user's grip area. So he can adjust the chair according to his personal needs even during working hours - as is well known, the body size decreases over the course of the day.

1 it should also be noted that the seat frame 11 forms the backbone of the chair 10, so to speak, ie this seat frame - with the height adjustment - can be used for different chair models, the seat and back cushions of which are connected to the seat frame 11 as required . This results in the required quantities for the seat frame 11, while the chair 10 in its final version can be customized depending on the intended use.

Naturally, numerous modifications and modifications are possible within the scope of the present invention. The arrangement with the hose 56 and the cage 57 can possibly also be used without the height adjustment.

Claims (16)

Chair with a height-adjustable backrest (25),
with a guide arrangement (14) for guiding a height-adjustable part (23) serving to fasten the backrest (25),
with a guide recess (28) provided in the central region of the guide arrangement (14) for the longitudinal guidance of a force-engaging member (34) connected to this height-adjustable part (23),
and with a toggle lever arrangement (44) engaging on the force application member (34), to which an actuating member (48), which can be actuated by the user of the chair (10), is assigned for adjusting the toggle lever arrangement (44). Chair according to claim 1, characterized in that the guide arrangement (14), forming the backbone of the backrest (25), so to speak, is arranged approximately in the central region of the backrest (25). Chair according to claim 2, characterized in that the guide arrangement (14), preferably on its side facing away from the seat (13) of the chair (10), has lateral guide members (19, 20) for the height-adjustable part (23). Chair according to one or more of claims 1 to 3, characterized in that the guide recess (28) provided on the guide arrangement (14) engages in guide grooves (35, 36) or the like which act between the height-adjustable part (23) and the force application member (34 ), or on the force application element (34) itself, are provided. Chair according to one or more of the preceding claims,
characterized in that the toggle lever arrangement (44) as the actuating member has a threaded shaft (47) on which a nut (45, 46), secured against rotation, can be displaced by rotating the shaft (47),
and that the toggle lever arrangement (44) has a lever (41, 42),
which is articulated on this nut (45, 46) and on the force application member (34). Chair according to claim 5, characterized in that the threaded shaft (47) has two threaded sections (45 ', 46'), one of which (46 ') has a right-hand thread and the other (45') has a left-hand thread and each of which has a counter-thread Locked nut (45, 46) with a corresponding internal thread,
and that the toggle lever arrangement (44) has two levers (41, 42) which extend between the force application member (34) on the one hand and the associated nut (45, 46) on the other hand. Chair according to one or more of the preceding claims, characterized in that the actuating member (48) for the toggle lever arrangement (44) is arranged approximately at the foot of the backrest (25) in such a way that it can be operated by the seated user. Chair according to one or more of the preceding claims, characterized in that the upholstery of the backrest (25) in the lumbar region is provided with a lumbar organ (55), the volume of which can be changed by the user. Chair according to claim 8, characterized in that the lumbar member (55) has an inflatable tube arranged essentially horizontally. Chair according to claim 9, characterized in that the hose (56) is assigned a holder (54, 63) in the backrest (25). Chair according to claim 10, characterized in that the holder (54, 63) on its side facing the back of the user has a cover (63) which can be flexibly deflected towards the back of the user when the tube (56) is inflated. Chair according to claim 11, characterized in that the cover has at least one flexible section (63) which is rotatable on one long side (58, 59) of the hose (56) and longitudinally displaceable and rotatable on the other long side (66, 67) of the hose is articulated. Chair according to one or more of claims 9 to 12, characterized in that a pump (74) and a drain valve (72) are associated with the hose. Chair according to claim 13, characterized in that the pump (74) and drain valve (72) are arranged below the seat surface (13) of the chair (10) and are connected via a pressure line (70) to the hose (56) serving as a lumbar organ. Chair according to one or more of claims 8 to 14, characterized in that the lumbar organ (55) is arranged on the height-adjustable backrest (25) in a region which, when the height of the backrest (25) is adjusted in the predetermined adjustment range ( H ), corresponds to the lumbar region Plenty of conceivable users. Use of a chair (10) according to one or more of the preceding claims as an office chair.

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