EP0772986B1 - Chair - Google Patents

Abstract

The chair has a pivoting device (24) incorporating a link (26) with two pivot arms (30,31) which face each other and held on a first link point (36,37) on the frame (18) and on a second link point (38,39) on the seat component (12). The chair also has a spring component (28,29) which activates the seat component with an elastic set-back force on pivoting. The link points of the link are arranged trapezoidally and the second link points are positioned approximately on a parallel to the connecting line of the first link points. The link points can form a mirror-symmetrical trapezium or an unsymmetrical trapezium. The spring component acts directly on a pivot arm.

Description

The invention relates to a chair with a frame on which a seat element holding a backrest by means of a Swivel device horizontally and transversely to its longitudinal axis is held pivotably, the pivoting device being a Joint with two facing each other, each on a first Articulation point on the frame and at a second articulation point on Seat element held swivel arms includes, as well as a Swivel element when swiveling with an elastic restoring force acting spring element.

Allow chairs with a swivel seat element to relax the seated person a tilt or Pivotal movement of the seat element and the held thereon Backrest by the seated person shifting his weight backwards. To avoid the front edge of the seat element when swiveling strongly, it is known that Swivel axis in the front area of the seat element too relocate. However, this has the consequence that the focus of the seated person and the swivel axis of the chair against each other are offset. So that the seat element is not already at sitting upright tilts back, but only when the seated his weight towards the backrest is usually shifted by the weight of the seated a preloaded spring balanced. A weight balance is only possible, however, if the preload is the weight the seated person is adjusted. A poor adjustment the preload of the spring means that either even when sitting upright, the seat element to the rear tends, or that a pivoting movement only takes place if the preload is applied using a certain force is overcome.

A chair is known from US-A-3,070,342, in which the Seat element pivotable on a swivel device on Frame is held, the pivoting device is a joint with two mutually facing pivot arms, each at a first articulation point on the frame and at one second articulation point are held on the seat element. The joint also includes the seat element when pivoting with an elastic Spring elements in the form of restoring force biased in the basic position of the seat element Coil springs. There are two springs on each side of the chair arranged. Will the seat element out of its basic position is pivoted, so that in each case one of the two springs Tension increases while the other coil spring is relaxed. The two springs of the joint thus act against each other. This has in the basic position of the seat element results in an unstable balance and brings about an overall unsatisfactory stability of the construction.

Based on the prior art known from US-A-3,070,342 Technology is the object of the invention, a chair of the generic type Art in such a way that he improved Has stability.

This task is described in the case of a chair Art solved according to the invention in that the spring element as no bias in a basic position of the seat element having torsion spring is formed.

The seat element can be swiveled to the frame in the construction according to the invention with the help of the two Swivel arms, each hinged to the frame and the seat element and face each other. With an upright posture the weight of the seated person acts equally on both Swivel arms, and since the two swivel arms facing each other are, with regard to the first articulation point of the one Torque caused by the corresponding swivel arm Torque of the other swivel arm compensated. When upright Sitting is independent of the focus of the person sitting its weight between the pivot points of the swivel arms, so that there is no inclination movement of the seat element. However, the seated person shifts his weight towards on the backrest, so the two swivel arms unevenly loaded by the first articulation point the torque acting on the swivel arm adjacent to the backrest no longer completely by the torque of the corresponding one other swivel arm is balanced so that the seat element from the one taken when sitting upright Basic position tends backwards. With asymmetrical loading the tilting movement of the two swivel arms takes place independently by the weight of the person sitting, only when the inclination movement an elastic restoring force from the spring element is exercised. A bias of the spring element in the Home position is not required. Regardless of the weight Only then does the seated person perform an inclination movement the seat element when the seated person lifts his weight backwards shifted.

Accordingly, the weight of the seated person is shifted a tilting movement towards the front edge of the chair the seat element to the front.

The design of a swivel device with a Basic position of the seat element has no preload Torsion spring has the advantage that only from the torsion spring then a force is exerted on the seat element when this is pivoted, it is irrelevant whether that Seat element is pivoted forward or backward. In In both cases, the torsion spring becomes elastic Restoring force exerted, while in the basic position none Torsion spring loaded. The chair construction thus does not have to be due to mutually canceling spring forces be held in the basic position. An unstable one This will balance the seat element in the basic position avoided.

It is expedient for the articulation points of the frame to be approximately trapezoidal to arrange, with the second articulation points approximately a parallel to the connecting line of the first articulation points are positioned. The swivel arms, each a first Articulation point on the frame with a second articulation point on the seat element connect, thus form the oblique sides of the trapezoid, while the connecting lines of the first two articulation points and the two second articulation points essentially are aligned parallel to each other. This results in a constructive particularly simple and inexpensive to manufacture Design.

In an advantageous embodiment of the invention provided that the articulation points are mirror-symmetrical Form trapezoid. The length of the two swivel arms is correct match. If the person sitting on both swivel arms exercises the same amount of force at first Articulation point of the swivel arms exerted on each other balanced, so that no inclination movement of the seat element he follows. Shifting the weight backwards with a symmetrical arrangement of the articulation points as well as a tilting movement of the seat element as a corresponding one Shift the weight forward.

If an inclination movement of the seat element is preferred in one Direction, it is advantageous if the articulation points form an asymmetrical trapezoid of the frame. In this case, the length of the two swivel arms is incorrect agree, so that with even loading of the two Swivel arms do not balance the corresponding torques an inclination movement of the seat element takes place. If such is to be prevented, the both swivel arms are loaded unevenly.

If an inclination movement of the seat element is preferred after done at the back, it is beneficial if the distance of the pivot points of the swivel arm adjacent to the backrest is greater than the distance between the articulation points of a front edge of the chair's adjacent swivel arm. With more even The load on the two swivel arms thus causes the torque a tilting movement of the swivel arm adjacent to the backrest. Sitting upright is also possible the seated person consciously shift their weight forward and thus apply greater force to the shorter swivel arm than the longer one. By choosing the relative length of the Both swivel arms, it is therefore possible, the preferred inclination movement of the seating element.

In an advantageous embodiment of the invention provided that the spring element directly on a Swing arm acts. In this case the swivel arm is used not only to hold the seat element on the frame, but also it also transmits the elasticity exerted by the spring element Restoring force on the seat element.

It is advantageous to assign a spring element to each swivel arm, because this causes the spring elements elastic restoring force evenly over the swivel arms is transferred to the seat element.

The spring element designed as a torsion spring can be used to achieve this a particularly space-saving arrangement, for example be positioned on the underside of the seat element.

Additional means for holding the spring element on Swivel arm can be avoided by the spring element is integrally connected to the swivel arm. this has also the consequence that it is in the transmission of the spring element elastic restoring force exerted on the swivel arm there is no loss of friction.

In a particularly preferred embodiment of the invention it is provided that the joint is formed in one piece in Form of a U-shaped bracket held on the seat element, the both legs are designed as torsion springs which is connected to a swivel arm projecting outwards, the free end aligned parallel to the legs and one in a corresponding bore of the Forms immersed pivot pin. The joint can for example be formed from a round rod made of spring steel be just bent accordingly and for example to be fixed on the underside of the seat element got to. Such an embodiment is therefore particularly inexpensive producible.

The following description of a preferred embodiment the invention serves in connection with the drawing the detailed explanation.

Figur 1:

eine perspektivische Ansicht eines Stuhls gemäß der vorliegenden Erfindung;

Figur 2:

eine Schnittansicht längs der Linie 2-2 in Figur 1;

Figur 3:

eine Unteransicht des in Figur 1 dargestellten Stuhls;

Figur 4:

eine vergrößerte Schnittansicht gemäß Figur 2 im Bereich der Schwenkvorrichtung mit im wesentlichen horizontal ausgerichtetem Sitzelement und

Figur 5:

eine vergrößerte Schnittansicht gemäß Figur 2 im Bereich der Schwenkvorrichtung mit nach hinten geneigtem Sitzelement.

Show it:

Figure 1:

a perspective view of a chair according to the present invention;

Figure 2:

a sectional view taken along line 2-2 in Figure 1;

Figure 3:

a bottom view of the chair shown in Figure 1;

Figure 4:

3 shows an enlarged sectional view according to FIG. 2 in the region of the swivel device with a substantially horizontally oriented seat element and

Figure 5:

an enlarged sectional view of Figure 2 in the region of the pivoting device with the seat element inclined to the rear.

In the drawing, a chair 10 is shown, which is an approximate horizontally aligned seat member 12 which in its opposite the front edge 13 of the chair, rear area is bent upwards and in one piece merges into a backrest 14 and on its upper side 15 a seat cushion 16 is arranged, and a frame 18 with a rectangular frame 19 and protruding vertically downwards Chair legs 20. The frame 19 is formed by each parallel spars 21 and Crossbars 22.

Between the seat element 12 and frame 18 is a swivel device 24 arranged by means of which the seat element 12 horizontally and across its longitudinal axis, i.e. parallel to Front edge 13 of the chair is pivotally held. The Swivel device 24 is formed by two identical, mirror images of each other on the top 15 opposite Bottom 17 of the seat element 12 fixed joints 25 and 26. These each include a U-shaped bracket 27, both of which are parallel to each other and transverse to the longitudinal direction legs 28 and 29 of the chair aligned as torsion springs are trained, to whom, to the outside and obliquely down towards the frame 19 of the frame 18 projecting, a swivel arm 30 or 31 connects, its free end aligned parallel to the legs 28, 29 is and forms a pivot pin 32 or 33. The both legs 28 and 29 of the U-shaped bracket 27 are over one aligned parallel to the longitudinal direction of the chair Longitudinal strut 34 connected in one piece. This has the Advantage that the legs 28 and 29, each having a torsion spring train, only immovable, but not rotatably held on the underside 17 of the seat member 12 must be, the required anti-rotation is done by the longitudinal strut 34. The immovable support of the legs 28 and 29 on the bottom 17 is done with the help of each two retaining tabs 35. The joints 25 and 26 are off Spring steel manufactured.

The pivot pins 32 and 33 dip into corresponding ones Blind holes, which on the mutually facing inner sides of the two longitudinal spars 21 arranged and in the drawing are not shown. Form the pivot pins 32 and 33 thus a first articulation point 36 and 37 respectively pivotable mounting of the swivel arms 30 and 31 on the frame 18. Form the second articulation points of the swivel arms 30 and 31 the transition areas 38 and 39 between the swivel arms 30, 31 and the adjoining, designed as torsion springs Legs 28 and 29 respectively. As clearly shown in FIG. 4 the articulation points form essentially horizontal aligned seat element 12 approximately a trapezoid, the Connection line of the first articulation points 36 and 37 essentially parallel to the connecting line of the second articulation points 38 and 39 is aligned and wherein the pivot arms 30 and 31 form the oblique sides of the trapezoid.

In Figure 4, the orientation of the pivot device 24 is at shown upright posture of the seated. This takes the seat element 12 is oriented essentially horizontally Basic position as the focus of the in the drawing not shown seated between the two second Articulation points 38 and 39 of the swivel arms 30 and 31 act and the first two pivot points 36 and 37 Compensate the acting torques. Relocated the seated his weight towards the back Backrest 14, so that the second pivot point 39 of the the backrest 14 adjacent swivel arm 31 loaded more heavily than the second articulation point 38 of the one adjacent to the front edge 13 Swivel arm 30, so that the swivel arm 31 and use it to lower the rear area of the seat element 12 during the swivel arm 30 and with it the front area lift the seat element 12 slightly. Through the swivel movement the swivel arms 30 and 31 is in the torsion springs trained legs 28 and 29 a torsional stress and thus caused an elastic restoring force, so that the swivel arms 30, 31 with one of the weight of Counteracting counterforce seated. This has a cushioning of the swivel movement of the swivel arms 30, 31 result. By shifting the weight of the person sitting in the direction of the backrest 14 thus takes Seat element 12 overall has an inclined position as in FIG 5 shown a.

The seated person shifts his weight towards the front edge 13, the seat element 12 takes a corresponding not shown in the drawing, inclined forward Position by the pivot arm 30 due to the larger Loading of the second pivot point 38 by the weight the seated person lowers while that of the backrest 14 adjacent pivot arm 31 lifts slightly. The thus form two joints 25, 26 of the swivel device 24 a total of an oscillating suspension of the seat element 12, regardless of whether the seated person is standing upright Weight occupies a substantially horizontal position by shifting weight forward and backward can be pivoted behind. There is no swiveling additional force is required as the torsion springs trained legs 28 and 29 in the basic position of the Seat element 12 no force on the swivel arms 30 and 31 exercise.

Claims (9)

1. A chair with a stand (18), to which a seat element (12) holding a backrest (14) is swivellably retained by means of a swivel device (24) horizontally and transversely to its longitudinal axis, wherein the swivel device (24) comprises a joint (25, 26) with two swivel arms (30, 31) turned towards one another, each retained at a first articulation point (36 or respectively 37) on the stand (18) and at a second articulation point (38 or respectively 39) on the seat element (12) and also a spring element (28, 29) acting with an elastic restoring force on the seat element (12) when swivelling,
   characterised in that the spring element is constructed as a torsion spring (28, 29) not having any initial tension in the starting position of the seat element (12).
2. A chair according to Claim 1,
   characterised in that the articulation points (36, 27, 38 29) of the joint (25, 26) are disposed roughly trapezoidally, the second articulation points (38, 39) being positioned roughly on a parallel to the connecting line of the first articulation points (36, 37).
3. A chair according to Claim 2,
   characterised in that the articulation points (36, 37, 38, 39) form a mirror-symmetrical trapezium.
4. A chair according to Claim 2,
   characterised in that the articulation points (36, 37, 38, 39) form a non-symmetrical trapezium.
5. A chair according to Claim 4,
   characterised in that the spacing of the articulation points (37 and 39) of the swivel arm (31) adjacent to the backrest (14) is larger than the spacing of the articulation points (36 and 38) of the swivel arm (30) adjacent to a front edge (13) of the chair (10).
6. A chair according to one of the preceding Claims,
   characterised in that the spring element (28, 29) acts directly on a swivel arm (30 or respectively 31).
7. A chair according to Claim 6,
   characterised in that a spring element (28 or 29 respectively) is associated with each swivel arm (30, 31).
8. A chair according to one of the preceding Claims,
   characterised in that the spring element (28, 29) is connected in one piece with a swivel arm (30 or 31 respectively).
9. A chair according to one of the preceding Claims,
   characterised in that the joint (25, 26) is constructed in one piece in the form of a U-shaped stirrup (27) retained on the seat element (12), the two legs (28, 29) of which are configured as torsion springs, to each of which a swivel arm (30 or respectively 31) is joined in outwardly protruding manner, the free end of which is aligned parallel to the legs (28, 29) and forms a swivel pin (32 or respectively 33) dipping into a corresponding bore of the stand (18).

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