Footcross, chair base and chair

Abstract

Base (1) for a chair, wherein the base (1) comprises a central opening (2) which is designed to receive and support a post (3) which is substantially vertical in an operating position of the base (1), and wherein the base (1) has at least three, preferably five, arms (4) which extend radially from the opening (2), wherein at least one of the arms (4) has a substantially U-shaped profile (7) or a substantially O-shaped profile (7) extending along its longitudinal direction (5) from an outer arm end (6), wherein the at least one arm (4) has a substantially I-shaped profile (8) or a substantially T-shaped profile (8) along its longitudinal direction (5), different from the U-shaped profile (7) or O-shaped profile (7).

Description

[0001] The present invention relates to a base for a chair, wherein the base comprises a central opening which is designed to receive and support a post which is substantially vertical in an operating position of the base, and wherein the base has at least three, preferably five, arms which extend radially from the opening, wherein at least one of the arms has a substantially U-shaped or substantially O-shaped profile extending along its longitudinal direction from an outer arm end.

[0002] Furthermore, the invention relates to a chair base and a chair with such a base.

[0003] Such cross bases are generally known from the prior art. Typically, as can be seen, for example, in documents CN 2508626 Y and DE 19841225 A1, the arms of such cross bases have a substantially continuous, uniform cross-sectional profile with relatively thick cross-sectional walls. This usually results, on the one hand, from the desire for the simplest possible manufacturing process, which is why the basic cross-section hardly changes along the longitudinal axis of the arms. On the other hand, the focus in the design of the cross bases is usually exclusively on constructing very stable bases, which often leads to over-dimensioned bases. In summary, such prior art solutions involve an unnecessarily large amount of material.

[0004] The object of the present invention is therefore to provide a cross base improved compared to the prior art, with an optimized support structure, in particular wherein the support structure requires the least possible use of material while complying with all necessary stability requirements.

[0005] This problem is solved by the features of claim 1, namely with a foot cross of the type mentioned at the outset, wherein the at least one arm of the foot cross has a profile other than a U-shaped or O-shaped profile, substantially an I-shaped or substantially a T-shaped profile along the longitudinal direction.

[0006] This type of design advantageously deviates from conventional approaches by employing an innovative, specifically optimized support structure. The base according to the invention naturally meets all standardized requirements, such as the BIFMA X5.1 "Footrest Static Load Test" and / or the BIFMA X5.1 "Footrest Durability Test" and / or the safety requirements of DIN EN 1335.

[0007] A major advantage of the invention is that the wall thickness of the arms can be significantly less than that of the base crosses of the prior art. This allows for a significant saving of material, which can lead to both more cost-effective manufacturing and a reduced CO2 footprint.

[0008] Furthermore, the reduced material requirements result in a lower weight for the base, which is of course very practical when handling a chair equipped with a base.

[0009] Another advantage is that the inventive design of the base cross can result in a slimmer construction, which in turn enables a visually appealing design.

[0010] The opening is preferably cylindrical in shape and / or geometrically shaped according to the post, in particular a gas spring, of the chair.

[0011] The opening can also be designed as a blind hole, so that the post can be inserted from above in the operating position.

[0012] The opening is designed to accommodate the post in a substantially vertical orientation, which in particular means that the orientation of the post may deviate from an exactly vertical orientation, e.g. due to unevenness of a substrate and / or due to manufacturing tolerances.

[0013] The profiles mentioned are essentially U-, O-, I-, and / or T-shaped, which in particular means that at least one arm consists of a main supporting structure in at least a U-, O-, I-, and / or T-shape.

[0014] The cross-sectional shape of the profiles may deviate from an exact U, O, I, and / or T shape. However, the U, O, I, and / or T shapes are clearly recognizable.

[0015] The arms extending radially from the opening are preferably arranged at regular intervals.

[0016] The arms can also be inclined downwards from the opening and / or be curved and / or swept along their longitudinal direction, particularly downwards towards a floor. This means, in particular, that the longitudinal axis can be inclined and / or curved, with the respective profile cross-section changing only slightly or insignificantly along the longitudinal axis.

[0017] The central opening is positioned centrally relative to the arms. This means, in particular, that the opening is located in the center of the base, preferably with all arms being of the same length.

[0018] The I-shaped profile can also be viewed as an H-shaped profile, especially a rotated one.

[0019] The U-shaped profile can also be viewed as a C-shaped profile, especially a rotated one.

[0020] Further advantageous embodiments of the invention are defined in the dependent claims.

[0021] It is preferably provided that the I-shaped or T-shaped profile, in its operating position, has a substantially vertically oriented web and, furthermore, a lower flange and / or an upper flange. This ensures, for example, optimal load transfer via the arms.

[0022] In a preferred embodiment, the I-shaped profile has a vertically oriented web, an upper flange and a lower flange.

[0023] In a preferred embodiment, the T-shaped profile has a vertically oriented web and an upper flange.

[0024] In another variant, the T-shaped profile has a vertically oriented web and a lower flange.

[0025] The orientation of the bridge may deviate from an exactly vertical alignment, e.g. due to unevenness of a substrate and / or due to varying wall thicknesses to improve force flow.

[0026] It is preferably provided that the I-shaped or T-shaped profile has stiffening ribs, preferably extending between the web and the lower flange and / or the upper flange, in particular symmetrically to a vertical plane of symmetry through the I-shaped or T-shaped profile. This can, for example, increase the stiffness, in particular the torsional stiffness, of at least one arm.

[0027] The orientation of the vertical plane of symmetry may deviate from an exactly vertical orientation, e.g. due to unevenness of a substrate.

[0028] In a particularly preferred embodiment, the I-shaped profile has stiffening ribs, preferably extending between the web and the lower flange and the upper flange, in particular symmetrically to the vertical plane of symmetry through the I-shaped profile.

[0029] In one embodiment, the T-shaped profile has stiffening ribs, preferably extending between the web and the lower flange and / or the upper flange, in particular symmetrically to the vertical plane of symmetry through the T-shaped profile.

[0030] The stiffening ribs can be, for example, honeycomb-shaped and / or zigzag-shaped and / or cross-shaped.

[0031] The lower flange and / or the upper flange may have a concave, preferably V-shaped in the operating position, and particularly preferably inverted V-shaped, recess. This may be advantageous, for example, to save additional material.

[0032] It is particularly preferred that the U-shaped profile is essentially oriented in reverse in the operating position, wherein legs of the U-shaped profile are essentially vertically oriented and wherein a side of the U-shaped profile arranged between the legs forms a top surface.

[0033] It is also possible that one side of the O-shaped profile forms the top.

[0034] The alignment of the legs may deviate from an exactly vertical alignment, e.g. due to unevenness of a substrate and / or due to varying wall thicknesses.

[0035] It may be provided that the sides of the U-shaped or O-shaped profile, in particular the legs of the U-shaped profile, have concave recesses. This can be advantageous, for example, to save additional material.

[0036] The cutouts can, for example, be pointed and / or rounded towards the outer end of the arm and / or correspond to a stress distribution within the arm. This means, in particular, that areas in the cross-section or profile with low stresses will have cutouts.

[0037] It is preferably provided that the U-shaped profile or the O-shaped profile has stiffening ribs, preferably in a view from below, which are cross-shaped.

[0038] It is particularly preferred that the top surface of the U-shaped profile or the top surface of the O-shaped profile and the upper flange of the I-shaped or T-shaped profile merge seamlessly. This ensures, for example, a continuous force flow within the arm, thereby advantageously avoiding stress concentrations.

[0039] It is particularly preferred that a wall is arranged between the U-shaped or O-shaped profile and the I-shaped or T-shaped profile, preferably wherein the wall forms a transition between the legs of the U-shaped profile and the web of the I-shaped or T-shaped profile. This ensures, in particular, a favorablely continuous force flow in the arm.

[0040] In particularly preferred embodiments, the wall is arranged between the U-shaped profile and the I-shaped profile, preferably wherein the wall forms a transition between the legs of the U-shaped profile and the web of the I-shaped profile.

[0041] In preferred embodiments, the wall is arranged between the U-shaped profile and the T-shaped profile, preferably wherein the wall forms a transition between the legs of the U-shaped profile and the web of the T-shaped profile.

[0042] It is preferably provided that the I-shaped or T-shaped profile extends along the longitudinal direction over between 50 and 80%, preferably between 60 and 70%, of the length of the at least one arm. This can mean that the at least one arm is I- or T-shaped near the opening and transitions directly or indirectly into a U- or O-shaped profile towards the arm ends. In this way, an efficient and material-efficient supporting structure can be achieved.

[0043] It is particularly preferred that the at least one arm has a support area at the outer end of the arm for supporting the base cross, preferably wherein the support area has a bearing opening, in particular a blind hole-shaped one, for receiving an insertable extension.

[0044] The support area can be designed to rest on a floor, a roller, a stopper, a sliding element, or the like.

[0045] The bearing opening can be designed to accommodate an extension of a roller, a stopper, a sliding element, or the like.

[0046] It is preferably provided that the support area has an outer wall that is closed on all sides, preferably with stiffening struts arranged between the bearing opening and the outer wall, in particular which are oriented radially to the bearing opening. In this way, a support force can be transmitted particularly well via the support area.

[0047] Preferably, the outer wall transitions into the O-shaped or U-shaped profile, particularly into the legs and the top surface of the U-shaped profile. This allows, for example, an advantageous continuous force transmission.

[0048] It is particularly preferred that the inner ends of the arms, facing the opening, form a region that is essentially concentric with the opening and has a reinforced double wall. This allows the chair post to be securely and stably supported by the base.

[0049] The shape of the concentric area may deviate from an exactly concentric arrangement, e.g. due to varying wall thicknesses to improve the force flow within the base.

[0050] Preferably, the concentric area towards the opening has radial stiffening struts, preferably spaced regularly apart from each other, which advantageously further increase the stiffness.

[0051] The stiffening struts within the double wall can also be shaped differently, for example zigzag-shaped and / or cross-shaped.

[0052] It is possible that the concentric area is open at the bottom in the operating position, particularly to save additional material.

[0053] It is preferably provided that an outer wall of the double wall transitions into the I-shaped or T-shaped profile, in particular into the web and the upper flange and / or the lower flange. This allows, for example, an advantageous continuous force transmission.

[0054] In a preferred embodiment, the outer wall transitions into the I-shaped profile, in particular into the web, the upper flange and the lower flange.

[0055] It is also conceivable that the concentric area has a vertical extension in the operating state. This could, for example, serve to provide a more stable mounting for the post.

[0056] The vertical extension can extend downwards and / or upwards in the operating position.

[0057] It is possible for the arms to be designed separately from one another and preferably connected to the opening and / or to each other, preferably detachably. This allows for a modular design of the base, which, for example, enables the easy replacement of individual, defective arms.

[0058] It is particularly preferred that the base cross be made at least partially and / or partially, preferably completely, of plastic.

[0059] Preferably the plastic is a thermoplastic plastic, in particular an engineering plastic, such as polyamide.

[0060] The plastic may include glass fibers, with a glass fiber content preferably being between 20 and 40%.

[0061] The base, especially at least one arm, can be, for example, an injection-molded part.

[0062] It is conceivable that the base cross has connecting elements to which additional components, such as cover elements for protection and / or improved visual design, can be attached.

[0063] Protection is also sought for a chair base for supporting a seat, comprising a base cross according to the invention, a post inserted into the opening, in particular a gas spring, and a connecting element attached to the post for fastening the seat.

[0064] Furthermore, protection is sought for a chair, in particular an office or work chair, comprising a chair base according to the invention, a seat attached to the connecting element and casters, stoppers, sliding elements and / or the like attached to the arms.

[0065] A base cross according to the invention can also be used with already known chair bases or chairs of the prior art and can also be installed subsequently.

[0066] Further advantages and details of advantageous embodiments of the invention will become apparent from the figures and the accompanying figure description. These show: Fig. 1 a first embodiment of a first foot cross according to the invention, Fig. 2-6 an arm of a second embodiment of a second foot cross according to the invention, Fig. 7-10 a third embodiment of a foot cross according to the invention and Fig. 11 a fourth embodiment of a foot cross according to the invention.

[0067] The Fig. 1 Figure 1 is a perspective top view of a first embodiment of a base 1 according to the invention for a chair, wherein the base 1 comprises a central opening 2, which is designed to receive and support a post 3, for example a gas spring, which is substantially vertical in an operating position of the base 1, and wherein the base 1 has at least three, preferably five, arms 4 which project radially from the opening 2, wherein at least one of the arms 4 has a substantially U-shaped profile 7 or a substantially O-shaped profile 7 along its longitudinal direction 5 starting from an outer arm end 6, wherein the at least one arm 4 has a substantially I-shaped profile 8 or a substantially T-shaped profile 8 along the longitudinal direction 5, which differs from the U-shaped profile 7 or O-shaped profile 7.

[0068] The Fig. 2-6 are views and sections of an arm 4 of a second embodiment of a foot cross 1 according to the invention, wherein the at least one arm 4 has a profile 8 along the longitudinal direction 5 that differs from the U-shaped profile 7 and is essentially I-shaped.

[0069] Alternatively, instead of the U-shaped profile 7, an O-shaped profile 7 could be provided and / or instead of the I-shaped profile 8, a T-shaped profile 8 could be provided.

[0070] The Fig. 2 Figure 1 shows at least one arm 4 from a perspective bottom view. In this particularly preferred embodiment, the I-shaped profile 8 in the operating position has a substantially vertically oriented web 9, a lower flange 10 and an upper flange 11.

[0071] In the event that a T-shaped profile 8 is provided instead of the I-shaped profile 8, the T-shaped profile 8 can have a lower flange 10 or an upper flange 11.

[0072] It is also conceivable that the T-shaped profile 8 has at least one area with a lower flange 10 and at least one area with an upper flange 11 along the longitudinal direction 5.

[0073] From the in the Fig. 2 As can be seen from the view shown, the at least one arm 4 has a support area 20 at the outer arm end 6 for supporting the base 1, preferably wherein the support area 20 has a bearing opening 21, in particular a blind hole-shaped one, for receiving an insertable extension, e.g. of rollers, a stopper, a sliding element or the like.

[0074] Preferably the support area 20 has an outer wall 22 that is closed on all sides, preferably wherein stiffening struts 23 are arranged between the bearing opening 21 and the outer wall 22, in particular which are oriented radially to the bearing opening 21.

[0075] In the Fig. 2 Sections of the concentric region 24 with a double wall 24 and an outer wall 26 are also shown. However, these features are in Fig. 11 even better presented.

[0076] In the Fig. 3 side view shown and in the Fig. 4 The section shown shows that preferably the I-shaped profile 8 or the T-shaped profile 8 extends along the longitudinal direction 5 over between 50 and 80%, preferably over between 60 and 70%, of a length 19 of the at least one arm 4.

[0077] Out of Fig. 3 It is further evident that it is preferably provided that the outer wall 22 transitions into the U-shaped profile 7, in particular into the legs 15 and the top 17 of the U-shaped profile 7.

[0078] From the in the Fig. 5 The section shown shows that the lower flange 10 and / or the upper flange 11 can have a concave, preferably V-shaped in the operating position, particularly preferably inverted V-shaped, core 14.

[0079] The core recess 14 can be provided for both an I-shaped profile 8 and a T-shaped profile 8.

[0080] From the in the Fig. 6 The section shown shows that the U-shaped profile 7 is preferably oriented in the operating position essentially in reverse, wherein legs 15 of the U-shaped profile 7 are oriented essentially vertically and wherein a side 16 of the U-shaped profile 7 arranged between the legs 15 forms a top surface 17.

[0081] It is preferably provided that the top surface 17 of the U-shaped profile 7 and the upper flange 11 of the I-shaped profile 8 merge into one another.

[0082] In the case that an O-shaped profile 7 is provided, preferably the top surface 17 of the O-shaped profile 7 and the upper flange 11 of the I-shaped profile 8 or alternatively of the T-shaped profile 8 would merge into each other.

[0083] In this embodiment, a wall 18 is arranged between the U-shaped profile 7 and the I-shaped profile 8, preferably wherein the wall 18 forms a transition between the legs 15 of the U-shaped profile 7 and the web 9 of the I-shaped profile 8. This is particularly evident from the Fig. 2 and 4 stand out.

[0084] In the following description of the embodiments shown in the figures below, the differences from the first two embodiments will be emphasized to avoid repetition. Otherwise, the above description of the first and second embodiments also applies, where applicable, to the embodiments described below.

[0085] The Fig. 7-10 are views and sections of a third embodiment of a base cross 1 according to the invention. In this embodiment, the I-shaped profile 8 or the T-shaped profile 8 has stiffening ribs 12, in particular which are zigzag-shaped.

[0086] The stiffening ribs 12 preferably extend between the web 9 and the lower flange 10 and / or the upper flange 11.

[0087] From the in the Fig. 7 The perspective top view shown indicates that the arms 4 are preferably designed separately from each other and are preferably connected to the opening 2 and / or to each other, in particular detachably.

[0088] The Fig. 8 essentially shows the same aspects as the Fig. 7 ; however, in a side view.

[0089] In the Fig 9 The section shown through the I-shaped profile 8 shows that the stiffening ribs 12 preferably extend symmetrically to a vertical plane of symmetry 13 through the I-shaped profile 8 or the T-shaped profile 8.

[0090] The Fig. 10 It essentially shows the same aspects as in the Fig. 6 shown with reference to the second embodiment.

[0091] The Fig. 11 Figure 1 shows a bottom view of a fourth embodiment of a foot cross 1 according to the invention. In this view, it is clearly visible that preferably the inner ends of the arms 4 facing the opening 2 form a region 24 that is substantially concentric with the opening 2. The concentric region 24 has a stiffened double wall 25.

[0092] In this embodiment, the concentric area 24 towards the opening 2 has radial stiffening struts 23, preferably spaced regularly apart from each other.

[0093] Furthermore, the concentric area 24 is open in the operating position below.

[0094] In this embodiment, the outer wall 26 of the double wall 25 transitions into the I-shaped profile 8 or the T-shaped profile 8, in particular into the web 9 and the upper flange 11 and / or the lower flange 10.

[0095] In all the illustrated embodiments, the arms 4 are slightly bent downwards along their longitudinal axes 5. However, the arms 4 can generally also be straight.

[0096] In all illustrated embodiments, the inner ends of the arms 4 are connected essentially horizontally to the opening 2, in particular to the concentric region 24, in the operating position. However, the arms 4 can also project and / or be connected at an angle to the side and / or downwards from the opening. Reference symbol list:

[0097] 1 Base 2 Opening 3 Post 4 Arm 5 Longitudinal direction 6 Outer arm end 7 U-shaped or O-shaped profile 8 I-shaped or T-shaped profile 9 Web 10 Lower flange 11 Upper flange 12 Stiffening ribs 13 Plane of symmetry 14 Core recess 15 Leg 16 Side located between the legs 17 Top 18 Wall 19 Length 20 Support area 21 Bearing opening 22 Outer wall 23 Stiffening struts 24 Concentric area 25 Double wall 26 Outer wall 27 Connection point

Claims

1. Base (1) for a chair, wherein the base (1) comprises a central opening (2) which is designed to receive and support a post (3) which is substantially vertical in an operating position of the base (1), and wherein the base (1) has at least three, preferably five, arms (4) which extend radially from the opening (2), wherein at least one of the arms (4) has a substantially U-shaped profile (7) or a substantially O-shaped profile (7) extending along its longitudinal direction (5) from an outer arm end (6), characterized by the fact that which at least one arm (4) along the longitudinal direction (5) has a profile that is different from the U-shaped profile (7) or O-shaped profile (7), being essentially I-shaped (8) or essentially T-shaped (8).

2. Foot cross (1) according to claim 1, wherein the I-shaped profile (8) or the T-shaped profile (8) in the operating position has a substantially vertically oriented web (9) and further a lower flange (10) and / or an upper flange (11).

3. Base cross (1) according to claim 1 or 2, wherein the I-shaped profile (8) or the T-shaped profile (8) has stiffening ribs (12), preferably which extend between the web (9) and the lower flange (10) and / or the upper flange (11), in particular symmetrically to a vertical plane of symmetry (13) through the I-shaped profile (8) or the T-shaped profile (8).

4. Foot cross (1) according to one of the preceding claims, wherein the lower flange (10) and / or the upper flange (11) has or have a concave, preferably V-shaped in the operating position, particularly preferably inverted V-shaped, core (14).

5. Foot cross (1) according to one of the preceding claims, wherein the U-shaped profile (7) is substantially reversed in the operating position, wherein legs (15) of the U-shaped profile are substantially vertically oriented and wherein a side (16) of the U-shaped profile (7) arranged between the legs forms a top (17).

6. Foot cross (1) according to one of the preceding claims, wherein the top (17) of the U-shaped profile (7) or a top (17) of the O-shaped profile and the upper flange (11) of the I-shaped profile (8) or the T-shaped profile (8) merge into one another.

7. Foot cross (1) according to one of the preceding claims, wherein a wall (18) is arranged between the U-shaped profile (7) or the O-shaped profile (7) and the I-shaped profile (8) or T-shaped profile (8), preferably wherein the wall (18) forms a transition between the legs (15) of the U-shaped profile (7) and the web (9) of the I-shaped profile (8) or T-shaped profile (8).

8. Foot cross (1) according to one of the preceding claims, wherein the I-shaped profile (8) or the T-shaped profile (8) extends along the longitudinal direction (5) over between 50 and 80%, preferably over between 60 and 70%, of a length (19) of the at least one arm (4).

9. Base cross (1) according to one of the preceding claims, wherein the at least one arm (4) has a support area (20) at the outer arm end (6) for supporting the base cross (1), preferably wherein the support area (20) has a bearing opening (21), in particular a blind hole-shaped one, for receiving an insertable extension, e.g. of rollers.

10. Foot cross (1) according to claim 9, wherein the support area (20) has an outer wall (22) closed on all sides, preferably wherein stiffening struts (23) are arranged between the bearing opening (21) and the outer wall (22), in particular which are oriented radially to the bearing opening (21).

11. Foot cross (1) according to claim 9 or 10, wherein the outer wall (22) transitions into the O-shaped profile (7) or the U-shaped profile (7), in particular into the legs (15) and the top (17) of the U-shaped profile (7).

12. Base cross (1) according to one of the preceding claims, wherein the inner arm ends of the arms (4) facing the opening (2) form a region (24) that is substantially concentric to the opening (2) and which has a stiffened double wall (25), preferably wherein the concentric region (24) to the opening (2) has radial stiffening struts (23) that are preferably spaced regularly apart from each other and / or is open at the bottom in the operating position.

13. Foot cross (1) according to claim 12, wherein an outer wall (26) of the double wall (25) transitions into the I-shaped profile (8) or the T-shaped profile (8), in particular into the web (9) and the upper flange (11) and / or the lower flange (10).

14. Foot cross (1) according to one of the preceding claims, wherein the arms (4) are formed separately from each other and are preferably connected to the opening (2) and / or to each other.

15. Base cross (1) according to one of the preceding claims, wherein the base cross (1) is made of plastic at least partially and / or in part, preferably completely.

16. Chair base for supporting a seat, comprising a base (1) according to one of claims 1 to 15, a post (3) inserted into the opening (2), in particular a gas spring, and a connecting element attached to the post (3) for securing the seat.

17. Chair, in particular office or work chair, comprising a chair base according to claim 16, a seat attached to the connecting element and casters, stoppers, sliding elements or the like attached to the arms (4).

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