Seating furniture with seat, backrest, and swivel mechanism

Abstract

Seating furniture having a seat with a base and a seat surface which can be pivoted relative to the base between an upright sitting position and a reclined resting position by means of a pivoting device about a horizontal transverse axis lying above the seat surface, and with a backrest, in particular an office chair. In order to improve the seating comfort and reduce the pressure on the undersides of the user's thighs when reclining, at least one spring element is provided which, when the seat surface is pivoted towards the reclining position, generates a restoring torque on the seat surface in the direction of the upright sitting position.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to furniture, such as seating furniture. More particularly, the present disclosure relates to seating furniture having a seat surface and a backrest, where the seat surface can be pivoted relative to a base about a horizontal transverse axis located above the seat surface by means of a pivoting device, in particular an office chair.BACKGROUND

[0002] Seating furniture including a swivel device has been previously described, for example by EP 3 193 670 (WO 2016 / 042127 A1), as well as EP 4 294 237 (WO 2022 / 174945 A1) and DE 10 2018 114 207 B3 (all three originating from the present applicant). All of these publications describe, among other things, a design for a swivel mechanism in which the seat surface is supported by a three-axis kinematic mechanism with a central point, allowing spherical movement around the central point. In this case, the seat surface is naturally also guided when it rotates around a (virtual) transverse axis running through the center of the spherical movement.

[0003] A variety of kinematics capable of pivoting the seat surface around a horizontal transverse axis above the seat surface have been previously described, including by: EP 1 090 568 B1, EP 2 381 816 B1, WO 2012 / 123102 A1 of the applicant, WO 2016 / 042127 A1 of the applicant, in particular FIG. 9 and the associated description, explained in more detail in WO 2013 / 029069 A1 of the applicant. Alternate kinematics having completely different designs have been described by DE 199 15 003 A1 or EP 3 476 254 A1 of the applicant.

[0004] The publication WO 2013 / 085214 A1 discloses an office chair with a split seat surface, the two parts of the seat connected in a spring-loaded manner.

[0005] U.S. Pat. No. 11,229,291 B1 discloses an office chair with a seat surface which may be tilted around a horizontal axis normal to a symmetry plane relatively high above the seating surface (forward-backward) and a horizontal axis laying in the symmetry plane, above, but relative near the seating surface (left-right). The backrest is not connected with the seat surface and does not participate in these movements but may be tilted by an extra mechanism. When leaning back, the front edge of the seat surface goes up and constricts the user's thighs from below.

[0006] WO 2008 / 094865 A1 discloses a great variety of office chairs (with 101 figs., 89 claims and 167 pages totally) with four horizontal pivot axes, with split seat surfaces (optionally with spring elements in between) and / or split backrests, optionally with arm rests which act as mechanism to move the front seat part and many similar variations.

[0007] The content of EP 3 193 670 (WO 2016 / 042127 A1), EP 4 294 237 (WO 2022 / 174945 A1), DE 10 2018 114 207 B3, WO 2013 / 085214 A1, U.S. Pat. No. 11,229,291 B1, WO 2008 / 094865 A1, EP 1 090 568 B1, EP 2 381 816 B1, WO 2012 / 123102 A1 of the applicant, WO 2016 / 042127 A1, WO 2013 / 029069 A1, DE 199 15 003 A1 or EP 3 476 254 A1, and U.S. Pat. No. 11,229,291 B1 are hereby incorporated by reference for all purposes.

[0008] Unfortunately, the use of any of the seating furniture described in the prior art can cause an uncomfortable feeling for the user after leaning back for some time. Another problem, which is just as significant in practice, is that when leaning back around the transverse axis, the front edge of the seat is raised and constricts the user's thighs from below. What is needed is an article of seating furniture that provides a solution to at least one of these design problems, and preferably provides a solution for both.SUMMARY

[0009] The present disclosure is directed to seating furniture, such as an office chair, having a seat with a base and a seat surface which can be pivoted relative to the base between an upright sitting position and a reclined resting position by means of a pivoting device about a horizontal transverse axis lying above the seat surface, and with a backrest. In order to improve the seating comfort and reduce the pressure on the undersides of the user's thighs when reclining, at least one spring element is provided which, when the seat surface is pivoted towards the reclining position, generates a restoring torque on the seat surface in the direction of the upright sitting position.

[0010] In one example, the present disclosure is directed to an article of seating furniture that includes a base; a seat having a seat surface, where the seat surface can be pivoted relative to the base using a pivoting device, the seat surface being pivotable about a horizontal transverse axis above the seat surface such that the seat surface can be pivoted between an upright sitting position and a reclined resting position; a backrest; and at least one spring element; such that when the seat surface is pivoted toward the reclined resting position the at least one spring element generates a restoring torque that urges the seat surface towards the upright sitting position.

[0011] The features, functions, and advantages of the disclosed seating furniture may be achieved independently in various embodiments of the present disclosure, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a depiction of a conventional office chair in a perspective view.

[0013] FIG. 2 is a depiction of the office chair of FIG. 1 in a side elevation view.

[0014] FIG. 3 is a depiction of the office chair of FIG. 1 in a side elevation view in a reclined configuration.

[0015] FIG. 4 is a depiction of a variant of a conventional office chair with a so-called tractor seat in a perspective view.

[0016] FIG. 5 is a depiction of the office chair of FIG. 4 in a side elevation view.

[0017] FIG. 6 is a depiction of the office chair of FIG. 4 in a side elevation view in a reclined configuration.

[0018] FIG. 7 depicts a user sitting upright in a conventional office chair.

[0019] FIG. 8 depicts the user and office chair of FIG. 7 with the user leaning back in the chair.

[0020] FIG. 9 is a depiction of an illustrative variant of an article of seating furniture according to the present disclosure in a perspective exploded view.

[0021] FIG. 10 is a side elevation view of a user seated in the seating furniture of FIG. 9.

[0022] FIG. 11 is a side elevation view of a user seated in the seating furniture of FIG. 9 while leaning back.

[0023] FIG. 12 is a depiction of another illustrative variant of an article of seating furniture according to the present disclosure in a perspective view.

[0024] FIG. 13 is an enlarged detail of the seating furniture of FIG. 12.

[0025] FIG. 14 is a cross-sectional side elevation view of the seating furniture of FIG. 12.

[0026] FIG. 15A is an enlarged detail of the seating furniture of FIG. 14. FIG. 15B is an enlarged detail of a variant of the seating furniture of FIG. 14.

[0027] FIG. 16 is a depiction of another illustrative variant of an article of seating furniture according to the present disclosure in a partial cross-section side elevation view.

[0028] FIG. 17 is an enlarged detail of the seating furniture of FIG. 16.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] As used in the present disclosure, the terms left, right, up, down, forward, and backward refer to the perspective of a user of the seating furniture when seated in the seating furniture. The terms “front,”“rear,”“above,”“below,”“inside,”“outside,” and so on are used in the generally accepted form and with reference to the seating furniture in its usual use position.Some Terms

[0030] Seat surface: This is movable relative to the base, at least pivotable about a (horizontal) transverse axis. Further pivoting about additional axes up to spherical mobility may be provided. The seat surface may be divided along a horizontal axis into a front part and a rear part, which is then firmly connected to the backrest, as known from the prior art. In this case, the distance between the backrest and the front end of the (rear) seat surface part firmly connected to the backrest is 50 mm to 300 mm in the area of the possible articulated or flexibly bent leg rest. The seat surface may be upholstered, which does not change the essential nature of the present disclosure.

[0031] Backrest: As stated in the application, it may be fixed, albeit resiliently, to the seat surface or its rear part. It may also be fixed, resiliently or hinged about a horizontal transverse axis to the base, as known from the prior art.

[0032] Plane of symmetry: divides the furniture into two parts along a vertical plane, whereby at least the seat and the backrest are actually divided into two equal parts that are symmetrical to each other; the remaining components and also the fastening elements on the seat and backrest may deviate from the symmetry without further ado. It should therefore be noted that the term “plane of symmetry” only applies cum salo granis, as the individual components and handles of seating furniture, such as office chairs, are definitely one-sided, but there is still a plane of symmetry for the seat and, if present, the backrest and armrests, which runs vertically when the seating furniture is in the rest position and swivels with the seat. It is this plane that is considered the plane of symmetry in the following.

[0033] Virtual axis(es): Since the pivot axis(es) of the seat surface are located above the seat surface, they do not consist of bearings, sleeves, or similar components, but are formed by various kinematics known from the prior art, such as the above-mentioned three-axis kinematics with a central point. It should be noted here that the version also known from the prior art with a central area instead of a central point can also be used in the seating furniture of the present disclosure.

[0034] Models corresponding to FIGS. 1 to 3, in accordance with the prior art, were constructed and tested for experimental purposes. The seating furniture, an office chair 1 or armchair, shown in FIGS. 1 to 3, has a base frame 6 with casters that run on the floor, the installation surface 7, and a gas pressure spring, at the upper end of which a base 2 is mounted that can rotate around the vertical axis 8 of the gas pressure spring and supports the swivel mechanism, a three-axis kinematic mechanism 3. This three-axis kinematics 3 in turn supports the seat surface 4 and forms a central point 9 (FIG. 5) around which the seat surface 4 and all parts connected to it can move spherically. It should be noted that the central point 9 does not have to lie on the vertical axis 8, and in most cases does not, but is offset from it, usually to the rear. This spherical pivotability also allows pivotability around a horizontal normal axis on a furniture symmetry plane. This symmetry plane 10 coincides with the drawing plane in FIGS. 2, 5, 6, 7, and 8. Of course, it is not a plane of symmetry in the mathematical sense, because the actuators and also the arrangement of the three-axis kinematics are typically asymmetrical, but it is a common term and for the seat surface and (if present) for the backrest and armrests, it is actually a plane of symmetry running vertically to the contact surface of the furniture in the rest position.

[0035] The normal axis mentioned, the transverse axis 26 (FIG. 6), is the axis around which the seat surface 4 and everything connected to it, in this case specifically the backrest, can be swiveled backward from the upright sitting position shown in FIG. 5 to a resting position or even a lying position. FIG. 6 shows such a backward-inclined position, which does not necessarily have to be the end position. The types of limitation of this swivel movement are well known from the prior art and do not require further explanation here.

[0036] With three-axis kinematics, movement around other axes passing through the central point 9 is always possible (but can be limited or prevented if desired). This is also known from the prior art, is not causally related to the seating furniture of the present disclosure, is well-known to those of ordinary skill in the art, and therefore does not need to be explained here.

[0037] In the conventional chair 1, which is exemplarily provided with a continuous seat surface 4, the front edge 11 of the seat surface 4 inevitably lifts when leaning back, as a comparison of FIGS. 2 and 3 clearly shows. This is not only uncomfortable, but also has medical disadvantages, as a closed seat shell (or, in general, a fixed position between the seat and backrest) restricts the movement of the hip joint. Of course, this problem also occurs when using kinematics other than the three-axis kinematics shown.

[0038] To solve this problem, a so-called saddle seat was tried out, as shown in FIGS. 4 to 6. Here, too, a three-axis kinematic system with a central point 9 and a transverse axis 26 (indicated by the circle around the central point) is shown as the swivel device. The saddle seat with a saddle seat surface 14, also known as a tractor seat, which has been used in various ways recently, can be applied in different designs. A largely flat version was deliberately used, as it comes closest to a conventional seat surface. The seat is designed to provide a recessed thigh support, like a saddle, while the middle section is approximately the size of a conventional seat surface. This middle section is necessary to ensure that a person attempting to sit on the front edge of the seat does not slip off.

[0039] As can be seen in particular from FIG. 4, the actual seat surface has a padded saddle-shaped support, which, even when leaning back, as shown in FIG. 6, significantly reduces the pressure on the thighs due to the significant shortening of the seat support at the front on both sides. on which the thighs usually rest with their front (lower) sections, a significant reduction in cutting in can be achieved. However, there is no change in the behavior of the restoring moment compared to the seating furniture of FIGS. 1 to 3.

[0040] It was also assumed that a similar design of the front edge of the thigh supports as in the seating furniture according to the aforementioned publications would result in a comparable seating experience. However, this assumption proved to be incorrect, as the situation is different with saddle seats. Due to the absence of a thigh support, the shorter seat surface on which one sits is perceived much more strongly. When leaning back, either with the entire upper body or by moving the pelvis back and forth, the edge of the seat lifts and creates slight pressure in the buttocks and thighs. This pressure is often not perceived as uncomfortable when first sitting down and moving, but can soon become annoying when sitting for long periods, especially due to the desired continuous pelvic movement.

[0041] Further investigations have revealed the following, which is explained in more detail in view of FIGS. 7 and 8: This is done using a chair with a divided seat surface 4 and 12, as described in detail in the above-mentioned WO 2022 / 174 945 A1, in order to illustrate the problem, also taking into account the raising of the front edge 11 of the seat, and to show the general applicability of the present disclosure. The hinged separation point between the two seat parts 4 and 12 was positioned so that it roughly corresponds to the location of the muscle fold between the buttocks and thigh muscles, or such that the seat part 12 ends shortly forward of the point of contact of a user's ischium (the ischial tuberosities, or “sit bones”) with the rear part of the seat surface 4. In most cases, this separation point is located in the aforementioned area between 50 mm and 300 mm from the backrest. This placement largely corresponds to the human musculoskeletal system, so that the movement between the seat surface parts is hardly noticeable or not noticeable at all, and certainly not perceived as uncomfortable. The arrangement can be seen in FIG. 7.

[0042] A representation of the swivel mechanism has been omitted here because it is not necessary.

[0043] The movement of the two seat parts 4 and 12 relative to each other takes place around a horizontal normal axis on the symmetry plane 10, which also coincides with the drawing plane in FIGS. 7 and 8. With regard to the kinematic connection of the movable seat surface part 12 to the rear seat surface part, reference is made to the applicant's publications mentioned at the beginning and does not need to be explained in more detail here as it is thoroughly described in the prior art.

[0044] An unpleasant aspect of leaning back the upper body is that the seat, and in particular its front part 12, also moves significantly upwards when the seat surface 4, 12 is divided. This happens because a moment must be created that supports the user's upper body in the direction of upright sitting. Therefore, the horizontal pivot axis 26, which runs perpendicular to the plane of symmetry of the chair (in the case of three-axis kinematics through the central point 9), must be positioned slightly behind the center of gravity of the seated person (this creates the restoring moment). The horizontal position of the center of gravity is given by the tip of arrow “A,” and the lever arm by the double arrow. Due to these geometric conditions (positioning of the seat end and the pivot axis), the front edge of the seat 11 is located significantly in front of the pivot axis 26, which, despite the change in angle between the seat parts 4, 12, leads to a noticeable lifting of this edge 11 when leaning back, as a comparison of FIGS. 7 and 8 shows.

[0045] A less significant but nevertheless noteworthy effect is that when leaning back (with a rigid upper body), the center of gravity is located above the pivot axis 26. Although this is not directly related to the seat edge 11, the effective radius (the distance between the center of gravity and the pivot axis 26) is reduced when leaning back, and the lever arm is shortened to the length of the double arrow B. This reduces the restoring torque when leaning back, which means that the person sitting feels less and less pressure from the backrest, as can also be seen from the comparison of FIGS. 7 and 8. This can cause discomfort for sensitive individuals. Ideally, this contact pressure (=restoring moment) should remain constant (at least approximately) over the entire range of motion or, better still, increase. However, since the pivot axis should correspond at least approximately to the moment pole of the human hip when walking, it cannot be raised so far that it is at the height of the center of gravity (not shown). This is the only way to geometrically compensate for the degressive behavior of the moment when leaning back.

[0046] It has thus been found that when the seat surface 4 and backrest 5 are tilted backward, it is desirable, on the one hand, to generate a return moment to the upright sitting position that is noticeable to the user and, on the other hand, to prevent the front edge 11 of the seat surface 4, 12 in the thigh area as little as possible as the seat surface as a whole, in order to reduce or, if possible, avoid constriction in the knee area of the thighs.

[0047] It was found to be desirable to position the horizontal axis of rotation (and thus usually also the central point) as far forward as possible, as this reduces or even prevents the front edge of the seat surface from being raised when leaning back. This applies to all types of seats, from classic, split, tractor seats or saddle-like seats, and the comb seats described below as new, but leads to the extensive (or even complete) loss of a restoring moment. The further partial finding leading to the solution is that a spring element is provided which serves as an energy store when leaning back and thus provides this restoring torque.

[0048] The spring element can take on a wide variety of shapes and be provided in a wide variety of locations, as described below.

[0049] The seating furniture of the present disclosure thus solves the problems by creating a corresponding restoring torque when the seat surface is pivoted. This can be achieved either by means of spring elements in the seat surface, including their special design, and / or by means of specially arranged spring elements between the base and the seat surface.

[0050] Additional features and advantages of the presently disclosed seating furniture will be explained in greater detail below with reference to the figures.

[0051] To explain the above-mentioned problem of the weakening restoring moment when swiveling the chair in more detail, reference is made again to FIGS. 7 and 8. These show a divided seat surface 4, the rear part of which, connected to the backrest 5 and the three-axis kinematics 3 (or other suitable kinematics, not shown in FIGS. 7 and 8), continues to bear the reference number 4, while the front part of the seat surface, which is movable relative to this part 4, bears the reference number 12.

[0052] FIG. 7 shows the center of gravity of the combination: the swiveling part of the user plus the swiveling part of the furniture with S. In connection with FIG. 8, the following can be seen: When leaning back, the horizontal distance of the center of gravity S from the pivot axis 26 changes (decreases) from “A” to “B” and causes only a small, and moreover decreasing, restoring moment, but in particular no restoring moment that increases when leaning back or even remains the same, which, as mentioned above, would be desirable.

[0053] A first variant according to the present disclosure for solving the problems mentioned is shown in FIGS. 9-11, views similar to FIG. 1 to 3 or 4 to 6: Here, the seat surface 4 is divided, like a comb, in the front area by incisions or elongated recesses that run parallel to the plane of symmetry 10 (drawing plane in FIG. 10), whereby the side parts 15, which are each mounted separately on the seat surface 4 (or are integral with it), are elastic, and thus springy, deformable upwards and downwards, thus enabling significantly easier lowering in the area of a user's thighs and thus causing significantly less constriction when leaning back. The middle part 16 is significantly firmer, almost rigid, compared to the side parts 15, as is usual with office chairs. A support provided as a comb seat surface 17 further reduces constriction by the front edge 11 in the embodiment shown, thus representing a pleasant further development.

[0054] FIGS. 10 and 11 show the situation when sitting upright and leaning back in a piece of furniture designed in this way. What is striking in FIG. 11 is the curvature of the lateral, springy part 15 facing the viewer, i.e., a spring device, of the seat surface.

[0055] Furthermore, the change in the horizontal position of the center of gravity S (which is not fixed in height and of which only one position in front of the central point 9 when sitting upright and behind the central point 9 when leaning back is shown) is clearly visible. From the position whose horizontal distance from the pivot axis (defined by the central point 9) is marked with A in FIG. 10, this changes to distance B in FIG. 11 when leaning back, but is on the other side and therefore no longer provides a restoring moment. As can be seen from the shape and position of the lateral, springy parts 15 of the seat surface, these are elastically deformed (spring effect) and therefore press from below, but over a large area, without substantially cutting into the front edge, on the user's thighs and vice versa. This contact force exerted by the user via the comb seat surface 28 results in an uprighting moment on the backrest 5, regardless of the horizontal position of the center of gravity in relation to the pivot axis, and thus in the desired uprighting moment.

[0056] This means that, depending on the design of the geometry, when the empty chair is tilted back (e.g., by hand, from “outside”), it may remain in the rest position, while when tilted back with and by a user sitting on the seat, it is returned to the upright position.

[0057] This shows how closely related the problems of constriction and upright positioning are in kinematic, static, and dynamic terms; which one is given more attention is a matter of opinion among users and designers.

[0058] FIGS. 12 to 15 show a perspective view, a detail of FIG. 12, a section along the plane of symmetry, and another detail. They show a piece of furniture similar to that in FIGS. 4 to 6. For reasons of clarity, this seating furniture only partially shows a three-axis kinematic system 3 between the base 2 and the seat surface 4, which allows the seat surface to perform a spherical movement around the central point 9 thus formed, and thus also a swiveling movement around the virtual transverse axis. The seat surface 4 is connected to a backrest 5 in a fixed but spring-loaded manner. To create the desired restoring torque, spring-loaded kinematics are used, which are structured as follows in the embodiment shown:

[0059] The rear end of a counter spring 21 designed as a leaf spring is arranged at the front of the base 2 so that it can rotate around a rear axis 25 that runs perpendicular to the plane of symmetry. The front end of the counter spring 21 is connected to the upper end of a leaf spring 19 so that it can rotate around an intermediate axis 20 that runs parallel to the rear axis 25. The lower end of the leaf spring 19 is in turn rotatably mounted about a leaf spring axis 18, which is also parallel to the rear axis 25, in a bracket 23 that is firmly connected to the seat surface 4. Furthermore, at least one (possibly preloaded) torsion spring 24 (FIG. 13) is provided in the bracket 23, which applies a clockwise torque to the leaf spring 19 as shown in FIG. 15A. When leaning back, this torsion spring is (possibly further) tensioned, thus generating a restoring torque in the direction of the upright sitting position, which increases with increasing backward swiveling.

[0060] The spring element, the torsion spring 24, is thus provided between the base 2 and the seat surface 4, whereby, of course, numerous variants of the structural design are available in light of the present disclosure and, in particular, this embodiment of the disclosed seating furniture. For example, the torsion spring can be provided at the intermediate axis 20 or, if no spherical movement is provided, it can be replaced or supplemented by a compression spring between the axes 18, 20 and / or a tension spring between the axes 20, 25.

[0061] Furthermore, FIG. 15A shows a block protruding downwards from the seat surface without a reference mark, which serves as a movement stop between the seat surface 4 and the clamping block 22, but which, of course, can be replaced without difficulty by another measure by a person skilled in the art with knowledge of the present disclosure. The leaf spring 19 and the counter spring 21 serve only as rods during the movement of the seat surface 4 around the pivot axis, but since, as explained above, spherical movement is also to be permitted, they are twisted during such spherical movement with a component “outside” the transverse axis, which would not be possible with “rigid” rods. This torsion also causes the desired righting moment around the respective moment axis during spherical movement, while the torsion spring(s) 24 provides the restoring moment around the transverse axis.

[0062] If no spherical movement is intended, a first rigid rod 21′ can be used in the place of counter spring 21, and a second rigid rod 19′ can be used in the place of leaf spring 19, as shown in FIG. 15B. Analogously to the spring-loaded kinematic of FIG. 15A, the first rod 21′ is rotatable about the rear axis 25, and the second rod 19′ is rotatable about the intermediate axis 20 as well as a second rod axis 18′ parallel to the rear axis 25.

[0063] Of course, this variant also works with a comb seat surface 28 or with a tractor seat surface or a one-piece seat surface that is consistent with the usual state of the art and also firmly supports the lower legs, or a split seat surface as shown in FIGS. 7 and 8. The kinematics that can be used for this are described in detail in the applicant's two publications, so that, with knowledge of the present disclosure, it is no problem for a person skilled in the art to use this in the present case as well.

[0064] FIGS. 16 and 17 show a variant similar to FIGS. 12 to 15 with a conventional seat surface 4 and backrest 5, in which the base 2 is connected in its front area to the seat surface 4 in the area of its front edge 11 by means of a (possibly preloaded) tension spring 27. When leaning back, this tension spring is (possibly further) tensioned, thus generating a restoring moment on the seat surface 4 in the direction of the upright sitting position, which increases with increasing backward swiveling. This restoring device can of course also be combined with all the seat surface variants described.

[0065] Armrests have not been shown or explained here because they are not of particular relevance to the details of the present disclosure. It should only be noted that all types of armrests can be used, whether they are connected to the base 2, the seat surface 4, or the backrest 5. The backrest, in turn, does not have to be connected to the seat in the manner shown (or in any other manner); all types of connections to the base (in which case the spring elements described here engage with the backrest) known from the prior art can also be used; this does not cause any problems with the disclosed seating furniture.

[0066] The seating furniture of the present disclosure can be used in its various variants with all types of kinematics, not only with the three-axis kinematics shown, if only a base 2 and a seat surface 4 are connected to each other in such a way that this connection provides at least one transverse axis 26 (pivot axis) normal to the plane of symmetry 10 of the seating furniture 1 above the seat surface 4. Whether pivoting about other axes is also possible, in particular about a longitudinal axis lying in the plane of symmetry, horizontal or inclined, as known from the prior art, is irrelevant to the details of the present disclosure.

[0067] More specifically, the kinematics previously disclosed by EP 1 090 568 B1, EP 2 381 816 B1, WO 2012 / 123102 A1 of the applicant, WO 2016 / 042127 A1 of the applicant, WO 2013 / 029069 A1 of the applicant, DE 199 15 003 A1, or EP 3 476 254 A1 of the applicant may be employed in the construction of the present seating furniture without limitation.

[0068] Typically, the vertical position of the pivot axis of the disclosured seating furniture is placed in the roughly estimated lower region of the user's thoracic spine, since then, especially if a swivel movement around a so-called longitudinal axis, which lies in the plane of symmetry of the furniture, is also possible, which in many cases is desirable for health and training reasons, namely to promote a comfortable movement of the pelvis and the adjacent part of the spine, which corresponds to the movement when walking. The user's center of gravity is then above the pivot axis, possibly above the central point.

[0069] The backrest 5 may be connected to the base in an articulated manner, if necessary resiliently, instead of to the seat surface. In this case, the spring element provided according to the present disclosure is inserted appropriately into a kinematic device which is provided between the seat element and the backrest in such concepts.

[0070] As shown, the base may have or be mounted on a gas pressure spring and a roller frame, and may thus be height-adjustable and, if necessary, spring-loaded with respect to the contact surface, and may be rotatable about the vertical axis of the gas pressure spring.

[0071] The description and explanation of limiting devices for the various movements (with the exception of the stop explained in FIG. 15) has been omitted; these are known and well-known from the prior art for a wide variety of applications and designs, so that it is possible for a person skilled in the art, with knowledge of the present disclosure, to make a suitable selection and design for the respective application without long deliberation, let alone original thinking.Selected Illustrative Embodiments

[0072] This section describes additional aspects and features of selected articles of seating furniture of the present disclosure, presented without limitation as a series of paragraphs, some or all of which may be alphanumerically designated for clarity and efficiency. Each of these paragraphs can be combined with one or more other paragraphs, and / or with disclosure from elsewhere in this application, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some of the suitable combinations.

[0073] A1. Seating furniture (1) with a base (2) and a seat surface (4) which can be pivoted relative to the base (2) between an upright sitting position and a reclined resting position by means of a pivoting device about a horizontal transverse axis (26) lying above the seat surface (4), and with a backrest (5), in particular an office chair,

[0074] characterized in that at least one spring element (15, 24, 27) is provided which, when the seat surface (4) is pivoted toward the reclined position, generates a restoring torque on the seat surface (4) toward the upright sitting position.

[0075] A2. Seating furniture according to paragraph A1, characterized in that the backrest (5) is connected to the seat surface (4) in a fixed, optionally spring-loaded manner.

[0076] A3. Seating furniture according to paragraph A1 or A2, characterized in that at least the areas of the leg rest of the seat surface (4), as seen from the backrest, end shortly after the seat bone and are followed by an optional leg rest which is either connected in an articulated manner to the rear part of the seat surface (4) or is designed without a joint by means of an elastically mounted leg rest.

[0077] A4. Seating furniture according to one of paragraphs A1 to A3, characterized in that the spring element (15) has or consists of springy lateral parts of a comb-like seat surface (28) which are elastically deformed when leaning back.

[0078] A5. Seating furniture according to paragraph A4, characterized in that the elastic deformation is caused by the downward pressure of the thighs of the user of the seating furniture.

[0079] A6. Seating furniture according to one of paragraphs A1 to A3, characterized in that the spring element (24) is provided between the base (2) and the seat surface (4).

[0080] A7. Seating furniture according to paragraph A6, characterized in that at the front of the base (2), the rear end of a counter spring (21) designed as a leaf spring is arranged, which is rotatable about a rear axis (25) that runs perpendicular to the plane of symmetry (10), the front end of which is connected in a rotatable manner to the upper end of a leaf spring (19) about an intermediate axis (20) that runs parallel to the rear axis (25), with the upper end of a leaf spring (19), the lower end of which is in turn rotatable about a leaf spring axis (18) also parallel to the rear axis (25) and mounted in a holder (23) fixedly connected to the seat surface (4), at least one torsion spring (24), which may be preloaded, being provided about at least one of the axes (19, 20) is provided with at least one torsion spring (24), which may be preloaded.

[0081] A8. Seating furniture according to paragraph A6, characterized in that the rear end of a rod is arranged at the front of the base (2) so as to be rotatable about a rear axis (25) which runs perpendicular to the plane of symmetry (10), the front end of which rod is connected in a rotatable manner to the upper end of a further rod, the lower end of which rod is in turn connected in a rotatable manner about an intermediate axis (20) running parallel to the rear axis (25), is connected to the upper end of a further rod, the lower end of which is in turn mounted in a holder (23) connected fixedly to the seat surface (4) so as to be rotatable about an axis also parallel to the rear axis (25), and in that at least one, optionally preloaded, torsion spring (24) is provided about at least one of the axes (19, 20).

[0082] A9. Seating furniture according to paragraph A6, characterized in that at the front of the base (2), is arranged at the front of the base (2) so that it can rotate about a rear axis (25) that runs perpendicular to the plane of symmetry (10), the rear end of a rod, the front end of which is connected in a rotatable manner to the upper end of another rod about an intermediate axis (20) that runs parallel to the rear axis (25), with the upper end of another rod, the lower end of which is in turn rotatable about an axis also parallel to the rear axis (25) and mounted in a holder (23) fixedly connected to the seat surface (4), and that a compression spring is provided between the axes (18, 20) and / or a tension spring is provided between the axes (20, 25).

[0083] A10. Seating furniture according to paragraph A6, characterized in that an end of a tension spring (27) is attached to the front of the base (2), the other end of which is connected to the front edge of the seat (11) below the seat surface (4).

[0084] A11. Seating furniture according to one of paragraphs A1 or A3, characterized in that the backrest (5) is connected to the base (2) in an articulated, optionally spring-loaded manner, and that the spring element is provided between the seat surface (4) and the backrest (5).

[0085] It should also be noted that in the description and claims, terms such as “lower region” of a suspension, reactor, filter, structure, or device, or, more generally, of an object, refer to the lower half and, in particular, the lower quarter of the total height; “lowest region” refers to the lowest quarter and, in particular, an even smaller part; while “middle region” means the middle third of the total height (width—length). All these terms have their common meaning when applied to the intended position of the object in question.

[0086] In the description and claims, “essentially” means a deviation of up to 10% of the specified value, if physically possible, both downwards and upwards, otherwise only in the meaningful direction; in the case of degree specifications (angle and temperature), this means ±10°.

[0087] All quantities and proportions, in particular those used to define and / or claim the invention, unless they relate to specific examples, are to be understood with a tolerance of ±10%:11%, for example, means from 9.9% to 12.1%. In phrases such as “a solvent,” or “one spring,” the words “a” and “one” should not to be construed as a numeral or numeric value, but as an indefinite article or pronoun, unless the context indicates otherwise.

[0088] Unless otherwise specified, the term “combination” or “combinations” refers to all types of combinations, from two of the components in question to a plurality or all such components; the terms “having,”“including,” and “containing” should be construed as non-limiting and having an equivalent meaning to “comprising.”

[0089] The characteristics and variants specified for the individual embodiments and examples disclosed herein may be freely combined with those of the other examples and embodiments and may in particular be used to characterize the seating furniture of the disclosure in the claims without necessarily entraining the other details of the respective embodiment or the respective example.LISTING OF REFERENCE NUMERALS01 Armchair, chair

[0091] 02 Base

[0092] 03 Three-axis kinematics

[0093] 04 Seat

[0094] 05 Backrest

[0095] 06 Base

[0096] 07 Contact surface

[0097] 08 Vertical axis

[0098] 09 Center point

[0099] 10 Plane of symmetry

[0100] 11 Front edge

[0101] 12 Movable seat surface part

[0102] 13 Tension spring

[0103] 14 Tractor seat

[0104] 15 Side parts

[0105] 16 Middle part

[0106] 17 Comb seat

[0107] 18 Leaf spring axis

[0108] 18′ Second rod axis

[0109] 19 Leaf spring

[0110] 19′ Second rod

[0111] 20 Intermediate axis

[0112] 21 Counter spring

[0113] 21′ First rod

[0114] 22 Clamping block

[0115] 23 Bracket

[0116] 24 Torsion spring

[0117] 25 Rear axis

[0118] 26 Transverse axis

[0119] 27 Tension spring (restoring tension spring)

[0120] 28 Comb seat surface

Claims

1. An article of seating furniture, comprising:a base;a seat having a seat surface, wherein the seat surface can be pivoted relative to the base using a pivoting device, the seat surface being pivotable about a horizontal transverse axis above the seat surface such that the seat surface can be pivoted between an upright sitting position and a reclined resting position;a backrest; andat least one spring element, such that when the seat surface is pivoted toward the reclined resting position the at least one spring element generates a restoring torque that urges the seat surface towards the upright sitting position.

2. The article of seating furniture according to claim 1, wherein the backrest is connected to the seat surface in a fixed manner.

3. The article of seating furniture according to claim 2, wherein the backrest is connected to the seat surface in a fixed but spring-loaded manner.

4. The article of seating furniture according to claim 1, whereinthe seat surface is divided into a front part and a rear part, and the front part of the seat surface further includes a leg rest;the leg rest is connected in an articulated manner to the rear part of the seat surface, or the leg rest is elastically mounted to the rear part of the seat surface without a joint; andthe leg rest of the seat surface ends shortly forward of a point of contact of a user's ischium with the rear part of the seat surface.

5. The article of seating furniture according to claim 1, wherein a front part of the seat surface is divided like a comb, and the at least one spring element includes resilient lateral parts of the comb-like seat surface that are elastically deformed when a user is leaning back in the article of seating furniture.

6. The article of seating furniture according to claim 5, wherein the elastic deformation of the resilient lateral parts of the comb-like seat surface is caused by a downward pressure of thighs of the user of the seating furniture.

7. The article of seating furniture according to claim 1, wherein the at least one spring element is provided between the base and the seat surface.

8. The article of seating furniture according to claim 7, further comprising a spring-loaded kinematic including a counter spring, a leaf spring, and at least one torsion spring;wherein a rear end of the counter spring is arranged at a front of the base so that the counter spring is rotatable about a rear axis that extends perpendicular to a vertical plane of symmetry of the article of seating furniture;a front end of the counter spring is connected to an upper end of the leaf spring such that the leaf spring is rotatable along an intermediate axis that runs parallel to the rear axis;a lower end of the leaf spring is mounted in a holder fixedly connected to the seat surface such that the leaf spring is rotatable about a leaf spring axis that is also parallel to the rear axis; andat least one torsion spring, which is optionally preloaded, is provided about at least one of the intermediate axis and the leaf spring axis.

9. The article of seating furniture according to claim 8, wherein the counter spring is configured to be another leaf spring.

10. The article of seating furniture according to claim 7, further comprising a spring-loaded kinematic including a first rod, a second rod, and at least one torsion spring;wherein a rear end of the first rod is arranged at a front of the base so that the first rod is rotatable about a rear axis that extends perpendicular to a vertical plane of symmetry of the article of seating furniture;a front end of the first rod is connected to an upper end of the second rod such that the second rod is rotatable along an intermediate axis that runs parallel to the rear axis;a lower end of the second rod is mounted in a holder fixedly connected to the seat surface such that the second rod is rotatable about a second rod axis that is also parallel to the rear axis; andat least one torsion spring, which is optionally preloaded, is provided about at least one of the intermediate axis and the second rod axis.

11. The article of seating furniture according to claim 7, further comprising a spring-loaded kinematic including a first rod, a second rod, and at least one spring;wherein a rear end of the first rod is arranged at a front of the base so that the first rod is rotatable about a rear axis that extends perpendicular to the plane of symmetry;a front end of the first rod is connected to an upper end of the second rod such that the second rod is rotatable along an intermediate axis that runs parallel to the rear axis;a lower end of the second rod is mounted in a holder fixedly connected to the seat surface such that the second rod is rotatable about a second rod axis that is also parallel to the rear axis; anda compression spring is provided between the second rod axis and the intermediate axis and / or a tension spring is provided between the intermediate axis and the rear axis.

12. The article of seating furniture according to claim 7, wherein an end of a restoring tension spring is attached to a front of the base, and the other end of the restoring tension spring is connected to a front edge of the seat below the seat surface.

13. The article of seating furniture according to claim 1, wherein the backrest is connected to the base in an articulated and optionally spring-loaded manner, and the spring element is disposed between the seat surface and the backrest.

14. The article of seating furniture according to claim 1, wherein the article of seating furniture is an office chair.

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