EP0208695B1 - Seating device with spring for the seat - Google Patents

Abstract

The seat of the seating device is hinged to its support arm (14) by means of a horizontal shaft (22) arranged at its front edge. The support arm (14) bears at different heights to a column (12) situated behind the seat (27). The energy accumulator of a spring device (F) is comprised of a coil spring of which the tension is adjustable as a function of the body weight so as to maintain the seat (27) in a medial area of the swivelling angle of the spring device (F). Thereby, the user of the device may cause a proportionally important oscillation of the seat (27) by a relatively small displacement of the gravity centre and avoid undesired tilting motions.

Description

The invention relates to a piece of seating furniture, in particular for children and adolescents, with a seat shell and backrest, with a support bracket supported on the floor by the rollers of approximately horizontal support arms, the lower portion of which is determined by the height of the support arms and the rollers from the smallest possible distance from Floor, which section merges into a lower adjustment section outside a vertical parallel projection of the seat shell, which includes an angle of 90 ° or less to the lower horizontal section, which lower adjustment section merges into a further backward inclined adjustment section for the backrest,

and with an approximately horizontal support arm that can be supported at different heights at the lower adjustment section, and with a horizontal axis supported on the support arm in the vicinity of the area of the seat shell intended for supporting the knees of the seating furniture user, via which a seat pan support is connected to the support arm, and with a spring device supported on the support arm and acting on the seat pan support, which dampens the pivoting of the seat pan support when reducing a pivoting angle limited by stops and drives it when enlarged.

A known seating of this type (DE-U-8 401 116.5) without variable seat part inclination has the advantage that when the seat part and backrest are adjusted in the same direction downwards or upwards, the available seating surface is reduced or enlarged in adaptation to the physiological leg length. A screw spring is arranged and designed in an approximately vertical arrangement between the seat pan support and the support arm in such a way that the user of the seating furniture can sit relatively "softly" by resting on the support member with cushioning on the support arm with the coil spring compressed to the maximum. A gradual gradation of the "softness" of the setting is possible by differently adjusting the preload of the helical spring that is subjected to pressure. From the same publication (exemplary embodiment of FIGS. 7-10) it is also known to provide a pretensionable torsion spring bar instead of a pivot axis, which allows a limited pivoting of the seat pan support relative to the support arm. The torsion spring rod dampens the pivoting of the seat pan support when the pivoting angle is reduced and drives this pivoting when the pivoting angle is increased. The spring characteristic of a torsion spring bar in an affordable price range is, however, very progressive. When the seat shell is loaded, rocking due to active shifting of the center of gravity by the user of the seating furniture in the sense of a further reduction in the swivel angle is only possible to a very modest extent, which basically applies to springs with a strongly progressive characteristic (see torsion spring bars in DE-AS-1429404; DE- OS-1 943 633).

Finally, an armchair is also known (CH-PS-340 976), the seat of which is pivotally mounted on its front side about a transverse axis. Helical springs supported on the transverse axis hold swiveling support arms with hook-shaped ends in a supporting position on the seat part when the armchair user assumes an upright sitting position. If the chair user leans backwards, the support arms are released from their support position. The seat swings downwards until an increasing equilibrium position is reached with the seat being constantly tilted backwards due to the increasing preload of the coil tension springs.

Proceeding from this, the object of the invention is to develop a piece of seating furniture of the type mentioned at the outset, the seat surface of which can be adjusted to the physiological length of the leg of the adolescent or child by adjusting the seat part and backrest, without any significant additional technical outlay in such a way that the seating furniture user already has one hand relatively slight changes in the center of gravity can cause a relatively strong rocking of the seat shell, and on the other hand unwanted rocking movements can be largely avoided, such rocking movement corresponding to a rocking movement which takes into account the urge to move, especially young users of seating furniture.

This object is achieved in that the energy accumulator of the spring device is formed by a helical spring that can only be loaded by tensile force, the pretension of which can be adjusted depending on the body weight such that the seat shell tilted backwards in contact with the stop in a central region of approximately 10 ° Swivel angle is held in suspension by the helical tension spring, the axis firmly connected to the seat pan support having a radial cantilever arm on which the rear articulated, approximately horizontally arranged, articulated in the direction of the screw axis (tension axis), hinged to a U-shaped bracket serving as the support arm Tension spring is articulated at a distance from the axis.

The arrangement of the support column behind the seat shell, ie outside of a vertical parallel projection of this seat shell, enables the use of relatively large coil springs in a horizontal arrangement, in which the load potential does not have to be fully exploited. On the one hand, this results in the possibility of an extremely deep lowering of the seat shell and, on the other hand, the prerequisite for the implementation of a spring device with an essentially linear characteristic. lso distant, the seating z. B. for children aged 4-6 years (Fig. 2), but also for young people aged 13-16 years and for adults (Fig. 1). The different rocking needs depending on the body weight and temperament of the user of the seating furniture can be realized individually by adjusting the pre-tension of the screw spring accordingly. With a relatively high preload, the seat pan support is held in suspension by the spring device at the upper limit of the middle range of the swivel angle with a relatively low seat part inclination. Unintended rocking movements are much easier to avoid than with a low preload of the coil spring, which preload results in a relatively large inclination of the seat part backwards. The spring space is sufficient to alternatively use coil springs of different lengths and thicknesses, in particular also those with a differently steep characteristic ("hard" or "soft" coil springs). It is desirable that relatively large rocking movements are possible due to slight arbitrary changes in the center of gravity.

A simple pretensioning device for the helical spring results in a design according to claim 4.

The invention is explained below with the aid of exemplary embodiments.

• Fig. 1 das Sitzmöbel in perspektivischer Darstellung bei einer Einstellung für Jugendliche im Alter ab etwa 13 Jahren und für Erwachsene,
• Fig. 2 das Sitzmöbel gemäß Fig. 1, bei einer Einstellung für Kinder im Alter von etwa 4 - 6 Jahren,
• Fig. 3 einen Ausschnitt aus dem in der vertikalen Symmetrieebene geschnittenen Sitzmöbel in vergrösserter Darstellung,
• Fig. 4 den Schwenkwinkel der Sitzschale im Verhältnis zur Zugdehnung der Schraubenzugfeder in schematischer Darstellung,
• Fig. 5 einen Schnitt nach Linie V-V von Fig. 3,
• Fig. 6 einen Ausschnitt im Bereich der Schraubenzugfeder in Unteransicht in vergrößerter Darstellung,
• Fig. 7, 8 eine Variasnte des Sitzmöbels in Seiten- und Rückansicht (ohne Fußgestell),
• Fig. 9 eine weitere Variante in einer Darstellung entsprechend Fig. 8 und
• Fig. 10 den Sitzteilträger gemäß Fign. 7, 8; 9 in Unteransicht.

Show it:

• 1 is a perspective view of the seating with a setting for young people from about 13 years and for adults,
• 2, the seating furniture according to FIG. 1, with a setting for children in the age of about 4-6 years,
• 3 shows a detail of the seating furniture cut in the vertical plane of symmetry on an enlarged scale,
• 4 shows the pivoting angle of the seat shell in relation to the tensile elongation of the helical tension spring in a schematic representation,
• 5 shows a section along line VV of FIG. 3,
• 6 shows a detail in the area of the helical tension spring in an enlarged view,
• 7, 8 a variant of the seating in side and rear view (without base frame),
• Fig. 9 shows a further variant in a representation corresponding to Fig. 8 and
• 10 the seat part support according to FIGS. 7, 8; 9 in bottom view.

First, the seating is based on the fig. 1 - 10 described:

The armchair with upholstered (padding 27b) seat shell 27 and backrest 28 comprises a support column 12 supported on the floor via horizontal support arms 10. In the exemplary embodiment shown in the drawing, this runs behind the seat shell 27, so that, as can be seen from FIG. 2, it is extremely low can be adjusted. The support column 12 is formed by a curved tube with tube legs running symmetrically to the vertical plane of symmetry b-b (FIGS. 5, 6), which merge into one another via a lower connecting web 12a and an upper connecting web 12e. The lower connecting web 12a is firmly connected to a head disc 10b of a corresponding radius. This head disc 10b has a concentric, vertical pin which is rotatably mounted in a pivot bearing 10c of the base frame. This base frame is formed by the star-shaped support arms 10 with rollers 11. The pipe legs of a lower horizontal section 12b of the support column 12 are bent over a central angle of over 90 ° and merge into a linear adjustment section 12c, which therefore includes an acute angle β (FIG. 1) to the vertical. An approximately horizontal support arm 14, designed as a bracket, for the seat shell 27 is supported on the adjustment section 12c in a height-adjustable manner. The adjustment section 12c for the seat shell 27 is followed by an oppositely inclined, linear adjustment section 12d for the backrest 28. This is displaceably and lockably supported by fastening elements 28a by means of sleeves 28b on pipe legs of this section 12d. For manufacturing reasons, the support column 12 is formed from two bow-like parts, the pipe legs of which are telescopically connected at the lower end of the adjustment section 12c to form the joint f. The tubular legs of the support arm 14, which merge into one another via the web 14a, have sections 14c which rise backwards, sleeve-side sections 14b and sections 14b which rise towards the front, as can be seen particularly from FIG. 3.

The rise angle of the mentioned sections 14c, 14b is approximately the same size and amounts to approximately 5-10 °.

The manner in which the sleeves 14d for the support arm 14 and the same sleeves 28b of the fastening elements 28a for the backrest 28 can be locked on the associated tubular legs of the support column 12 can be seen in FIG. 3. The sleeves 14d; 28b are lined with a plastic sleeve 14e, which can be pressed onto the jacket of the associated pipe leg with a set screw 14i for deformation.

A carrier (seat shell carrier 13) for the seat shell 27 is pivotally connected to the carrier arm 14 by means of a horizontal axis 42. This is pivotably mounted in the immediate vicinity of the area 27a of the seat shell 27 intended for supporting the hollow of the knee of the user of the seating furniture in the support arm 14. The Swivel bearings 26 are formed by bores in vertically arranged tabs which are fastened on the semicircular web of the support arm 14. The seat pan support 13 consists of angle profiles arranged symmetrically to the plane of symmetry bb, which are arranged mirror-symmetrically to one another. Horizontal profile legs 13h are attached to the seat shell 27. Vertical profile legs 13v are each firmly connected to the adjacent free end of the axis 42, so that the seat pan support 13 forms a rigid, pivotable unit with the axis 42. The axis 42 has a radial extension arm 35. A tension spring 57 of the spring device F, which is supported on the rear on the support arm 14, is articulated at a distance from the axis 42 on the extension arm 35 by means of hooks. It is designed as a helical tension spring 57 articulated on the rear of the support arm 14, as can be seen from FIGS. 3, 5, 6. The Schrabenzugfeder can be pretensioned by means of a pretensioning device which comprises a threaded bolt 36 running in the pull axis a - a, which is in threaded engagement on the rear side with a pretensioning nut 40 supported on a stationary part of the seating furniture. An eye at the front end of the threaded bolt 36 is penetrated by a hook of the wire of the tension spring 57. The biasing nut 40 is supported on a crossbar 14e of the support arm 14 via a washer 41. The seat shell 27, which is inclined backwards at maximum tensile extension of the helical tension spring 57, can be freely pivoted about the axis 42 over a pivot angle α. With a pre-tensioning of the tension coil spring 57 adapted to the body weight and the individual seating habits and needs of the user of the seating furniture, the seat shell 27 is kept suspended from the tension coil spring 57 within the central region M of the swivel angle a, that is to say with a tension stretch deviating from the maximum stretch c - c. as can be seen in particular from FIG. 4. The tension axis a - a of the coil spring 57 extends approximately horizontally. The swivel angle a is approximately 10 ° in the illustrated embodiment. It is limited by mechanical stops.

Elastic buffer elements 18 attached to the horizontal profile legs 13a limit the pivoting movement of the seat shell 27 downwards as stops. This pivoting movement is limited at the top by means of a tab 19 fastened to a vertical profile leg 13v of the seat part carrier 13, which engages behind a tubular leg of the carrier arm 14 with a bent stop end 19a (FIG. 3). During the swiveling movement, the cantilever arm 35 passes a position in which it is perpendicular to the pull axis a - a or it reaches such a position approximately at maximum tensile extension of the helical tension spring 57. With minimal tensile extension of the helical spring, the seat shell 27 is slightly inclined forward. 4, the extreme upper and lower pivot positions of the seat shell 27 are indicated with No and Nu and the central region M of the pivot angle a is shown. When changing the swivel angle a, the position of the pull axis a - a also changes slightly. In the example of FIG. 4, it is slightly inclined downwards at maximum tensile elongation.

In the further exemplary embodiments of FIGS. 7, 8 and 9 and FIG. 10, the reference numerals of components, which are functionally comparable to the corresponding components in the exemplary embodiment described, but are designed differently, are provided with one or two index lines (e.g. support column 12 in FIGS. 6; 12 'in FIGS. 7, 8 and 12 "in FIG. 9). The two further exemplary embodiments mentioned essentially differ from the exemplary embodiment according to FIGS. 1-6 in that the backrest 28'; 28" with the seat part carrier 13 forms a rigid unit which can be pivoted about the axis 42 by being connected to this seat part support 13 by means of a support tube 61 which is bent over an angle of more than 90 °. This support tube, with its lower end section 61a, which runs approximately parallel to the seat shell 27, is axially displaceable in a sleeve 60 and can be axially fixed in different positions by means of the locking screw 64.

This sleeve 60 is attached to a connection plate 62 which is welded to the angle profiles of the seat pan support 13. A sleeve 28a 'or 28 "of the backrest 28' or 28" is fitted onto the upper end section 61b of the support tube 61 and can be locked at different heights by means of the adjusting screw 63. In this case, the prestressing device is arranged on the front of the tension coil spring 57.

As a result, the preload nut 40 'is supported on the extension arm 35'. On the back, the helical tension spring is articulated on the support arm 14 via the crossbar 14e. In the exemplary embodiment in FIGS. 8, 9, the tube legs of the support column 12 'run vertically in the adjustment section 12c' and are bent backwards and horizontally in order to merge into one another via a web. In the variant according to FIG. 10, the tube legs of the support column 12 "in the adjustment section 12c" form an acute angle to the vertical and at the end of this adjustment section 12c "are bent into an opposite inclination in order to merge into one another via a web.

The support arm 14 '; 14 "and the associated sleeves 14d ';14d" correspond in structure and function to the support arm 14 with the associated sleeve 14d in the example of FIGS. 1-6. This also applies to the axis 42, which is constructed as follows in all exemplary embodiments (FIG. 3, 5): A bearing axis 42a is received directly in the pivot bearings 26. In the axial sections outside of the pivot bearing 26, the bearing axis 42a is fully enclosed by sleeves 42b which are firmly connected to the bearing axis 42a. The boom 35 is on the middle sleeve 42b welded. Cover sleeves 42c, which enclose the sleeves 42b, axially fix the axis 42 between the vertical profile legs 13v, which are welded at least to the bearing axis 42a, but expediently also to the end cover sleeves 42c, which in turn are fixedly connected to the bearing axis 42a via sleeves 42b are.

If the user of the seating sits down, the seat shell 27 is pivoted downward about the axis 42 from a seat part inclination No according to FIG. 4. This results in a corresponding pivoting of the cantilever arm 35. through which the coil spring 57 is increasingly biased. The swiveling movement, which reduces the swivel angle, comes to a standstill due to the increasing pretension of the helical tension spring 57 in a central region M (FIG. 4) of the swivel angle. In the standstill position, the seat pan 27 is held in suspension, unless the user changes his center of gravity significantly through active or unconscious movements. If the tension of the helical tension spring 57 is relatively large, the standstill position will rather lie in the upper part of the central region M. Unwanted rocking movements can be avoided if the preload is relatively high. Desired rocking movements are easier with a relatively small preload and can be realized in a playful manner in a larger swivel angle range, the extreme seat part inclination Nu not being achieved as a rule.

Claims (5)

1. Chair, especially for children and teenagers, having a seat shell (27) and back-rest (28), having a supporting frame (12) supported on the floor by the castors of substantially horizontal base legs (10), the lower portion (12b in Figs. 1, 2; 12b' in Fig. 7; 12b" in Fig. 9) of said frame being disposed at as small a distance as possible from the floor, such distance being determined by the height of the base legs and the castors (11), which portion (12b; 12b', 12b") extends into a lower adjustment portion (12c in Figs. 1, 2; 12c' in Fig. 7 and 12c" in Fig. 9) externally of a vertical parallel projection of the seat shell (27), said adjustment portion subtending an angle of 90° (Fig. 7) or less (Figs. 1, 2, 9) relative to the lower, horizontal portion (12b; 12b'; 12b"), wherein the back-rest (28) is horizontally adjustable to alter the usable seating area, and having a substantially horizontal support arm (14), which is supportable at different heights on the lower adjustment portion (12c; 12c'; 12c"), as well as having a horizontal shaft (42), which is supported on the support arm (14) close to the area (27a) of the seat shell (27) for supporting the backs of the knees of the chair user, and which shaft serves to connect a seat shell support member (13) to the support arm (14), and having a spring mechanism (F), which is supported on the support arm (14) and engages with the seat shell support member, said spring mechanism suppressing the tilting of the seat shell support member (13) when a swivel angle (a), defined by detent members (18, 19) is decreased, and stimulating said tilting when said swivel angle is increased, characterised in that the unit for storing the force of the spring mechanism (F) is formed by at least one helical tension spring (57), which is exclusively loadable by tension, the pre-stressing of said spring being adjustable according to the body weight, such that the seat shell (27), which is inclined rearwardly upon abutment against the detent member (18), is held in suspension by the helical tension spring (57) within a middle range (M) of the swivel angle (a), which is about 10°, wherein the shaft (42), which is securedly connected to the seat shell support member (13), has a radial extension arm (35), on which the helical tension spring (57) is pivotally mounted at a distance from the shaft (42), the rear end of said spring being pivotally mounted on a cross-member (14e) of the U-shaped support arm (14), which spring is disposed substantially horizontally and is stressed in the direction of the helical axis (tension axis a - a).

2. Chair according to claim 1, characterised in that the back-rest (28'; 28") forms a rigid unit with the seat support member (13) and is adjustable, through the intermediary of a supporting tubular member (61), formed as an angular member, in a means (sleeve 60) for guiding the seat (27), which means extends substantially parallel to the seating area (embodiments of Figs. 7 - 10).

3. Seat shell according to claim 1 or 2, characterised in that the extension arm (35) is positioned approximately normal to the tension axis (a - a) of the helical tension spring (57) when the helical tension spring (57) is at its maximum extension, and, when the helical tension spring (57) is at its minimum extension, the seat shell (27) is inclined forward.

4. Chair according to claim 3, characterised in that the helical tension spring (57) can be prestressed by means of a pre-stressing device which comprises a threaded bolt (36) extending along the tension axis (a - a) and is in threaded engagement with a pre-stressing nut (40), which is supported on a stationary part of the chair.

5. Chair according to one of claims 1 - 4, characterised in that the shaft (42) is accommodated in swivel bearings (26) which are mounted on a semicircular cross-member (14a) of the U-shaped support arm (14), and in that the seat shell support member (13) is securedly connected to the free ends of the shaft (42) through the intermediary of vertical profile legs (13v) of two angular profiles disposed symmetrically relative to the plane of symmetry (b - b).

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