EP1258212B1 - Chair, particularly office-chair, with adjustably preloaded backrest - Google Patents

Abstract

The guide track for the spring holder (34) is fitted to the seat support (2) and the adjuster (5) is joined at one end to the spring holder (44) and the far end is joined to the backrest support (3) at adjustable distance from the support axis (33). The adjuster consists of a tension-loaded draw lever (5) pivoted at one end to the spring holder (44) and engaged with the backrest support (3) at variable distance from the axis (33). The driver pin (53) used to engage the lever with the support (3) is fitted to the lever (5) in a slot (35) whose ends are variably spaced from the axis (33).

Description

The present invention relates to a chair, in particular Office chair, with one of a central chair pillar or more chair legs worn seat carrier, with a from the seat support worn seat plate and with a from one under the seat plate to the rear Backrest worn backrest, with the backrest support on the seat support around a horizontal, in chair transverse direction extending axis pivotally mounted and by means of at least one spring with an adjustable Force is applied to the backrest in the direction biased to the back of a chair user, the Spring is a compression or tension spring in an attack point at a distance from the axis of the backrest support attacks, wherein the attacking on the backrest end of the Spring is held on a sliding spring holder, on a spring-longitudinally extending spring guide track is guided, and where the distance between the point of attack and the axis by a chair user operable actuator is changeable.

A chair of the type mentioned is known from DE 43 24 542 A1 known. In this known chair, the spring is a Screw compression spring extending over a pivoting abutment supported against the front part of the seat support. At its other end, the compression spring is supported against the sliding spring holder. This penholder is on a guide rod in rod longitudinal direction slidably; the rod is in turn inside the Coil spring arranged. The pen is here with his facing away from the spring end face on a contact surface of the backrest carrier, whereby the backrest support with the biasing force is applied. The guide rod runs through the contact surface of the backrest carrier through and stands at its free end with the Actuator in connection. The actuator is here Screw. The set screw is stored in the seat carrier and has a lying below the seat support Turn handle on. By turning the knob, which is in its interior contains an adjusting nut is the adjusting screw in a direction perpendicular to the guide bar adjustable, whereby the distance of the point of application of Spring on the backrest support of the pivot axis can be changed. This can be done accordingly torque acting on the backrest carrier by the user of the Chair are set.

A disadvantage is considered in this known chair, that to achieve a noticeable change in the backrest biasing force the user of the chair one large number of revolutions on the turning handle of the set screw must perform. This is the operation of the Chair for the user cumbersome and uncomfortable. Another disadvantage is seen in that to change the backrest biasing force the spring with her backrest bearer pointing end in total must be pivoted. It must therefore below the seat plate a correspondingly large space be kept free, in which the pivoting of the spring takes place. hereby is the arrangement of the mechanical parts for the Generation of the backrest biasing force relative big and needs a lot of space, which is both production technology as well as optically unfavorable.

Another chair with comparable function is off US Pat. No. 4,709,962. To generate the seat back biasing force here serves a symmetrical Arrangement of two parallel compression springs surrounding one in between arranged hydraulic element for detection the backrest in a predetermined position are supplemented. To change the backrest preload force here serves an adjustment, the is formed from a plate, on the one hand pivotable with the seat carrier and on the other hand with the seat carrier side End of the compression springs is connected. For pivoting This plate around its pivot axis serves a Threaded spindle manually by a user of the chair is rotatable. Depending on the pivoting position of the plate results in a larger or smaller distance of the attack point of the compression springs on the backrest support of its pivot axis. Because of the different Leverage results in a different way Backrest biasing force.

A disadvantage is considered in this known chair, that the adjustment of the backrest biasing force By means of the threaded spindle cumbersome and time consuming is because to achieve a noticeable Verschwenkungsweges the plate a significant number of spindle revolutions is required. In addition, each results Adjustment of the plate at the same time an adjustment of the length the compression springs, which causes additional changes yield the spring force. The disadvantage is in this context Also, that the threaded spindle against the force of Pressure spring must work. The user of the chair must therefore an unfavorable large force for the rotation of the spindle apply, which makes the operation uncomfortable. Furthermore subject to the threaded spindle of a high mechanical Load, the correspondingly stable constructions requires. As a result, the production of the chair is expensive and expensive.

For the present invention, therefore, the task, to create a chair of the kind mentioned above avoids the disadvantages presented and in which the setting the seat back biasing force by the Users of the chair can be done quickly, easily and easily can, at the same time the chair without loss of reliability structurally simpler and cheaper to produce should be.

The solution of this task succeeds according to the invention with a Chair of the type mentioned above, characterized is that the spring holder leading spring track in a fixed position and with fixed orientation on the seat support is arranged and that the actuator by a pivotable lever is formed, wherein the actuator forming lever on the one hand by means of a pivot joint connected to the pen and together with this is displaceable along the spring guide track and on the other hand, with the backrest in one at a distance from the axle variable, by pivoting the lever adjustable engagement is available.

In the chair according to the invention, the adjustment is advantageous the backrest biasing force for the user simplified, because with unloaded backrest the Spring holder by the spring to the end of its spring guide track is pushed, thereby forming a stop and in this position the actuator is relieved. The so relieved actuator is with little effort adjustable by the user of the chair and in the desired Position brought by the user of the Chair corresponds to desired backrest preload force. A mechanical translation like one Adjusting screw or a threaded spindle is, is here due to the ease of movement of the actuator in Relieved condition no longer needed. This is contributing improved ease of use and simplification the construction and thus to a cheaper Manufacturability of the chair at. Is advantageous Furthermore, the achievable compact design, because the spring changes its position or direction when adjusting the Actuator not because the spring holder leading Guideway in a fixed position and with fixed alignment is arranged in the seat carrier. So will too no space for a total pivoting of the spring more needed under the seat carrier. Finally advantageous the cornering forces for the spring of the guideway and slidably guided therein Pen holder added, so that the actuator itself lighter and easier to construct. Thereby The production of the chair is cheaper.

In a further embodiment, it is preferably provided that the actuator is a drag lever loaded on train, one end of which is pivotally connected to the spring holder is and its other end in the distance from the axis variable engagement with the backrest support stands. The execution of the actuator as an on Train loaded drag lever allows a relatively light Execution of the actuator, for example in the form of a punched sheet metal part, since such a component at a given Sizing significantly higher tensile forces than Can absorb shear forces.

In a further embodiment of the chair according to the invention is provided that the engagement of the finger lever with the backrest support provided by a drag lever Driving pin, which in an adjustable position in a slot in the backrest carrier is formed, wherein the ends of the slot different from the axis, around which the backrest support is pivotable away lie. The combination of driving pin and slot is structurally simple and reliably fulfills the intended Tasks, due to the simple construction the items whose production cost is possible. Also the assembly of the chair during its manufacture is beneficial easy.

To the drag lever with the least possible effort To be able to adjust, preferably the slot is arcuate on a radius around the pivot axis of the finger lever.

On the one hand to ensure a compact design and on the other hand arrange the spring or the springs low to be able to, the invention proposes that the backrest support one beyond its pivot axis, one Lever arm forming extension and that the Point of application of the spring in the extension is.

Another measure to achieve the desired compact Construction is that the extension of the Backrest support relative to the rest of the backrest support down bent down or angled.

To achieve favorable leverage effects run prefers the longitudinal direction of the extension and the Longitudinal direction of the spring in the unloaded condition of the backrest approximately at right angles to each other.

To ensure that the adjustment of the finger lever the spring tension of the spring or springs practically Not affected, the drag lever is expedient from a in the longitudinal direction of the spring facing center position over one extending to both sides of it Angle range adjustable.

So that a user of the chair according to the invention the adjustment the backrest biasing force as possible convenient and easy to do is preferably the Drag lever with an operating lever for modification and determination of the pivoting position of the finger lever provided relative to the backrest support.

It is further preferred that the drag lever and its operating lever to a two-armed Lever forming component are summarized, the Swivel bearing with a manually overridden, one automatic lever adjustment excluding frictional force is executed. This way is without any special further action ensures that one by the user the chair set backrest preload force remains until he makes a new setting.

Finally, preference is given to the chair according to the invention provided that the spring one in the chair longitudinal direction is extending compression spring whose front end in one fixed spring holder near the front edge of the seat plate at Seat support is supported and whose rear end with the the backrest is engaged spring end. With This arrangement of the spring or springs becomes a concentration the chair mechanism on the area substantially between the middle of the seat plate and its front edge reached; behind this area is then only the Backrest support and the optionally provided actuating lever for the adjustment of the backrest preload force. This results also visually a tidy and clear picture of the mechanics of the chair.

Figur 1:

einen Stuhl in Seitenansicht in schematischer Darstellung, in einem unbelasteten Zustand,

Figur 2:

einen Ausschnitt aus Figur 1 in Form eines leicht vergrößerten Vertikalschnitts,

Figur 3:

ebenfalls einen Ausschnitt aus Figur 1 in gleicher Darstellungsweise wie Figur 2, nun mit einer versetzten Schnittebene,

Figur 4:

den Stuhl aus Figur 1, nun aber in einem belasteten Zustand, mit einer ersten Einstellung der Rückenlehnen-Vorbelastungskraft und,

Figur 5:

den Stuhl aus Figur 1, in gleicher Darstellungsweise wie in Figur 4, nun mit einer anderen Einstellung der Rückenlehnen-Vorbelastungskraft.

An embodiment of the chair according to the invention is explained below with reference to a drawing. The figures of the drawing show:

FIG. 1:

a chair in side view in a schematic representation, in an unloaded condition,

FIG. 2:

1 shows a detail from FIG. 1 in the form of a slightly enlarged vertical section;

FIG. 3:

likewise a detail from FIG. 1 in the same representation as FIG. 2, now with an offset cutting plane,

FIG. 4:

the chair of Figure 1, but now in a loaded condition, with a first adjustment of the backrest biasing force and,

FIG. 5:

the chair of Figure 1, in the same representation as in Figure 4, now with a different setting of the backrest biasing force.

FIG. 1 of the drawing shows a chair 1 in one schematic side view, the chair 1 here as Office chair is running. The supporting part of the chair 1 forms a seat support 2, which has a conventional cone block 23 is connected to a central chair column 21. At the bottom of the chair column 21, not shown here is usually a base with Roll.

The seat support 2 extends from the upper end of Chair column 21 slightly rising to the front, i. in the Drawing figure to the left and is at its front end hingedly connected to a seat plate support 22. On the top plate support 22 carries a seat plate 20, which is the seat for a user of the Chair 1 forms and the means of the hinged seat plate support 22 is pivotable. Near her rear end the seat plate is supported by means of a hinge connection 32. The hinge joint 32 is with its other End hinged to a backrest support 3, the seat carrier 2 below the seat panel 2 to the rear, i. in the Drawing to the right, runs. At the far end of the Backrest support 3, a backrest 30 is attached, the supports the back of a chair user.

The backrest support 3 is by means of a pivot axis 33rd pivotally connected to the seat support 2 and at this stored, wherein the pivot axis 33 in the horizontal direction runs across the chair 1.

The backrest support 3 has an axis 33 beyond Extension 34, relative to the rest of the backrest support 3 is angled downwards. At this extension 34 engages the one end 41 of a compression spring. 4 on, with its other end 42 near the leading edge the seat plate 20 is supported on the seat support 2. Either the first end 41 and the second end 42 of Spring 4 is in each case in a spring holder 44, 45th held. The front spring holder 45 is fixed to the Seat support 2 connected while the rear spring holder 44 relative to the seat support 2 in a provided therein Spring guide track 24 in the longitudinal direction of the spring 4 slidably is guided. The spring 4 exercises on the extension 34 of the backrest support 3 from a force for that ensures that the backrest 30 with a toward the Back of the chair user pointing bias force is charged.

To this biasing force, the backrest 30 on exercise the back of the chair user, adjust as needed is to the chair 1, an actuator 5 in Form provided a pivotable rocker arm. The one end of the finger lever 5 is about a pivot axis 55 pivotable on the sliding, rear spring holder 44 articulated; the other end of the finger lever 5 is with a driver pin 53 provided in a slot 35th in the extension 34 of the backrest carrier 3 engages. The Slot 35 runs on a radius around the Swivel axis 55 of the finger lever 5. The center of the Mitnehmerzapfens 53 forms the point 43, in which the spring 4 and the force exerted by this force on the backrest support 3, here its extension 34 attacks. By pivoting the finger lever 5 to his Pivot axis 55 in the sense of the pivot arrow 55 'can the Distance of the attack point 43 from the axis 33 to the the backrest support 3 is pivotable, be changed. In the state shown in Figure 1, the point of application 43 its minimum distance from the axis 33; this ensures due to the leverage effect that the backrest 30th a relatively low biasing force on the back of the chair user. By pivoting the Toggle lever 5 counterclockwise about his Pivot axis 55, the distance of the attack point 43 of the axis 33 increases, which according to the leverage laws to an increase in the biasing force of Backrest 30 toward the back of the chair user leads. To facilitate the adjustment of the finger lever 5, this is integral with an actuating lever 50 executed, extending from the pivot axis 55 to the rear, i. in the drawing to the right, extends. The pivot bearing in the area of the pivot axis 55 is expedient with such a friction force executed that the drag lever 5 by pressing the Operating lever 50 is manually adjustable, but one undesirable automatic adjustment is excluded.

When unloaded backrest 30, this takes the in FIG 1 position shown. In this state is the displaceable Penholder 44 at the rear, i. in the drawing right end of its spring track 24 at. In this Condition is the drag lever 5 with relatively little Force in his swivel position changeable, so that for the adjustment of the backrest biasing force only a small amount of effort from the user of the Chair must be applied. The occurring lateral Executives for the spring 4 are here from the Spring guide track 24 and the rear spring holder 44 applied, so that the drag lever 5 performed relatively easily can be. In addition, act on the drag lever. 5 no lateral forces leading to an automatic adjustment could lead the cam follower 5.

About the manual adjustability of the backrest biasing force In addition, the chair 1, as is known, a synchronous mechanism. This means that the Seat plate 20 and the backrest 30 synchronously be pivoted, with the arrangement of the various Swivel axes and levers the coupling is done so that at a lowering of the rear part of Seat plate 20, the backrest 30 by a pivot angle the seat plate excess swivel angle is pivoted back and down.

Figure 2 of the drawing shows a somewhat enlarged view a detail of the chair 1 according to FIG. 1 in the region of the displaceable spring holder 44, which in the associated spring guideway 24 in the seat support 2 in Longitudinal direction of the spring 4 is guided displaceably. In the unloaded state shown in Figure 2 Backrest 30, which is not visible in Figure 2, is located the spring holder 44 at the rear, i. in Figure 2 right End of the spring guide track 24 at.

At the front, i. pointing to the left in the drawing Side of the spring holder 44 supports the rear, i.e. in the drawing right end 41 of the compression spring 4 from.

In dashed lines which is the actuator forming Drag lever 5 located, the drag lever. 5 here in its counterclockwise pivoted Position is drawn. In this state is the driving pin 53 of the rocker arm 5 at the bottom stop the arcuate slot 35 in the extension 34 of the Lehnenträgers 3. Thus has in this position of the Rocker arm 5 of the point 43 of the spring 4 its maximum distance from the axis 33 to that of the backrest support 3 is pivotable.

On the far right in FIG. 2, the cone block 23 can be seen, the connection of the seat plate 2 for not shown here Chair column 21 forms. At the top of Figure 2 is still a small section of the seat plate 20 recognizable. The operating lever 50 for the finger lever 5 is shown in FIG 2 not shown.

Figure 3 shows the same representation as the figure 2 also a section of the chair 1 according to FIG 1, now with an offset towards the viewer Cutting plane. In contrast to Figure 2 is now in FIG 3, the spring 4 is not cut but in side view visible, noticeable. The right end of the spring 41 rests on the rear, displaceable spring holder 44, the in his here largely hidden spring track 24th is guided. The drag lever 5 is also in here its maximum counterclockwise pivoted Position dashed lines, so that here, too Engagement point 43 of the spring 4 its maximum distance from the axis 33 has. With regard to the further in FIG 3 appearing reference numerals will be to the description referenced Figure 2.

Figure 4 of the drawing shows in contrast to the figures 1 to 3 now the chair 1 in a loaded condition, in which the seat plate 20 in the rear area after down and the backrest 30 pivoted back and down is. The coupling of the pivoting movements of Seat plate 20 and backrest 30 causes in a known Way the joint 32 between the bottom of Seat plate 20 and the backrest support 3.

The connected with the not here marked chair column Seat support 2 maintains its position; relative to that the backrest support 3 pivoted clockwise. hereby is the extension 34 of the backrest support 3 also pivoted clockwise about the axis 33, whereby the spring 4 is compressed. The rocker arm 5 is as far as possible in the chair 1 according to FIG pivoted clockwise, so that the point of application 43rd its minimum distance r20120 from the axis 33 occupies. Because of the relatively short lever arm that is by the compression spring 4 exerted torque accordingly relatively small, creating a relatively small biasing force the backrest 30 on the back of a user of the chair 1 is generated.

In Figure 5 of the drawing is in the same representation as in Figure 4, the chair 1 also shown in a loaded state, but now the drag lever 5 assumes its counterclockwise maximum pivoted position. In this pivoting position of the finger lever 5, the point of application 43 of the spring 4 on the extension 34 has its maximum distance r ₂ from the axis 33 about which the backrest support 3 is pivotable. Due to this now relatively long lever arm, a correspondingly greater torque is exerted by the spring 4 on the pivotable backrest support 3, resulting in a correspondingly large biasing force of the backrest on the back of a user of the chair 1.

As a comparison of FIGS. 4 and 5 illustrates, retains the spring 4 regardless of the Verschwenkungsstellung of the rocker arm 5 their position and their course, so that except a change in the distance r between Point 43 and axis 33 no influence on the spring 4 takes place.

Furthermore, Figures 4 and 5 illustrate that the Slot 35 in the extension 34 of the backrest support. 3 approximately in the radial direction to the axis 33, so that although the slot 35 has an arcuate shape, one approximately linear adjustment of the distance r during pivoting of the toggle lever 5 results. This is a good one Adjustability of the backrest biasing force ensured by a user of the chair 1.

Finally, a comparison of Figures 4 and 5 shows that with smaller backrest preload force a smaller spring travel x ₁ for the spring 4 and larger backrest preload force results in a greater travel x ₂ for the spring 4, which ergonomically favorable for different heavy chair users is.

To achieve a stable and durable construction of the chair 1 can be two parallel to each other extending backrest support 3 may be provided, which then correspondingly by two mutually parallel Springs 4 are acted upon. The same then the spring holders 44, 45, the spring guide track 24 and the Cam follower 5 double.

As can be seen from the drawing figures is here used as a spring 4, a coil spring; alternative For this purpose, the use of a gas spring is possible, this then additionally the feature of adjustability may have their length, which then creates a adjustable basic position of the seat plate 20 and the backrest 30 is enabled.

Claims (11)

1. A chair (1), in particular an office chair, comprising a seat base (2) that is supported by a central chair column (21) or several chair legs, comprising a seat plate (20) that is supported by said seat base (2) and comprising a backrest (30) that is supported by a backrest base (3) extending underneath the seat plate (20) in a backward direction, wherein the backrest base (3) is mounted to the seat base (2) such that it can be pivoted about a horizontal axis (33) extending in transverse direction in relation to the chair, and wherein said backrest base (3) is subjected to an adjustable force by means of at least one spring (4), said force preloading the backrest (30) towards a chair user's back, wherein the spring (4) is a compression spring or a tension spring which, at a distance (r) from the axis (33), acts on the backrest base (3) at a point of application (43), wherein the end (41) of the spring (4) that is acting on the backrest base (3) is mounted to a sliding spring holding mechanism (44) which is retained in a spring guiding track extending in the longitudinal direction of the spring, and wherein the distance (r) between the point of application (43) and the axis (33) can be readjusted by a control element (5) to be actuated by the user of the chair,
   characterized in that
   the spring guiding track (24) retaining the spring holding mechanism (44) is arranged on the seat base (2) at a fixed position and in fixed alignment and that the control element (5) is formed by a swiveling lever, wherein the lever forming the control element (5) is, on the one hand, connected to the spring holding mechanism (44) by means of a swivel joint (55) and is, together with said spring holding mechanism (44), sliding along the spring guiding track (24) and is, on the other hand, in engagement with the backrest base (3), the distance (r) of said engagement from the axis (33) being variable and said engagement being adjustable by swiveling the lever.
2. A chair according to Claim 1, characterized in that the control element (5) is an idler lever (5) under tensile stress, one end of which is connected to the spring holding mechanism (44) such that it can be swiveled and the other end of which is in engagement with the backrest base (3), with the distance (r) of said engagement from the axis (33) being variable.
3. A chair according to Claim 2, characterized in that the engagement of the idler lever (5) with the backrest base (3) is formed by a driving lug (53) which is arranged at an adjustable position in an elongated hole (35) in the backrest base (3), wherein the ends of the elongated hole (35) are unequally spaced apart from the axis (33) about which the backrest base (3) can be swiveled.
4. A chair according to Claim 3, characterized in that the elongated hole (35), having the form of a bend, is arranged along a radius about the swivel axis (55) of the idler lever (5).
5. A chair according to anyone of the preceding claims, characterized in that the backrest base (3) comprises an extension (34) forming a lever arm projecting beyond the swivel axis (33) of said backrest base (3), and that the point of application (43) of the spring (4) is positioned in said extension (34).
6. A chair according to Claim 5, characterized in that the extension (34) of the backrest base (3) is bent or angled down in relation to the remaining backrest base (3).
7. A chair according to Claim 6, characterized in that the longitudinal direction of the extension (34) and the longitudinal direction of the spring (4) are extending approximately at right angles to each other, when the backrest (30) is in its unloaded state.
8. A chair according to anyone of Claims 2 through 7, characterized in that the idler lever (5), starting from a central position pointing in the longitudinal direction of the spring (4), can be adjusted across an angular region that extends to either side of said central position.
9. A chair according to anyone of Claims 2 through 8, characterized in that the idler lever (5) is provided with an actuating lever (50) for changing and defining the swivel position of the idler lever (5) in relation to the backrest base (3).
10. A chair according to Claim 9, characterized in that the idler lever (5) and its actuating lever (50) are comprised to provide a component forming a double-armed lever, the pivot of which is provided with a frictional force that can be overcome manually but excludes any self-readjustment of the lever.
11. A chair according to anyone of the preceding claims, characterized in that the spring (4) is a compression spring extending in the longitudinal direction of the chair, the front end (42) of said compression spring being supported in a spring holding mechanism (22) that is fixed to the seat base (2) near the front end of the seat plate (20), and the rear end (41) of said compression spring being the spring end that is in engagement with the backrest base (3).

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