CHAIR WITH A SELF-ADJUSTING JOINT

Abstract

The invention relates to a self-adjusting joint (11) which is designed to receive an end of a chair leg of an active dynamic chair, comprising a hollow inner cylinder (12) that comprises an upper and lower end-face edge (12o, 12u) and a hollow outer cylinder (13) that is arranged around the exterior of the inner cylinder (12) and has an upper and lower end-face edge (130, 13u), each of which is offset relative to the upper and lower end-face edge (12o, 12u) of the inner cylinder (12) in the axial direction (A), and a first compression spring section (11a) that consists of a plurality of cylinder bodies or cylinders (15a) which surround the inner cylinder (12) and between which a respective elastomer section (14a) is arranged so as to connect the cylinder bodies or cylinders, and a second compression spring section (11b) that is arranged at a distance from the first compression spring section in the axial direction (A) and consists of a plurality of cylinder bodies (15b) or cylinders which surround the inner cylinder (12) and between which a respective elastomer section (14b) is arranged so as to connect the cylinder bodies or cylinders.

Claims

1. A self-adjusting joint which is designed to receive an end of a chair leg of an active dynamic chair, comprising a hollow inner cylinder that comprises an upper and lower end-face edge, and a hollow outer cylinder that is arranged around the exterior of the inner cylinder and has an upper and lower end-face edge, each of which is offset relative to the upper and lower end-face edge of the inner cylinder in the axial direction (A), and a first compression spring section that consists of a plurality of cylinder bodies or cylinders which surround the inner cylinder and between which a respective elastomer section is arranged so as to connect the cylinder bodies or cylinders, and a second compression spring section that is arranged at a distance from the first compression spring section in the axial direction (A) and consists of a plurality of cylinder bodies or cylinders which surround the inner cylinder and between which a respective elastomer section is arranged so as to connect the cylinder bodies or cylinders.

2. The self-adjusting joint according to claim 1, wherein the first elastomer sections between the first cylinder bodies are formed separately from the second elastomer sections of the second cylinder bodies and that a hollow space is formed between the respective elastomer sections.

3. The self-adjusting joint according to claim 1, wherein the multiple cylinder bodies are arranged like onion skins relative to each other.

4. The self-adjusting joint according to claim 3, wherein the end-face edge (R) of the respective cylinder bodies located farther outwards is arranged offset in the axial direction (A) relative to the end-face edge (R) on the same side of the cylinder bodies located farther inwards.

5. The self-adjusting joint according to claim 1, wherein the cylinder bodies of the first compression spring section are formed separately from the cylinder bodies of the second compression spring section.

6. The self-adjusting joint according to claim 1, wherein the cylinder bodies of the first compression spring section are connected to, or formed integrally with, the cylinder bodies of the second compression spring section as joint cylinder bodies.

7. The self-adjusting joint according to claim 1, wherein the inner cylinder has a wall with different wall thicknesses in the axial direction (A).

8. The self-adjusting joint according to claim 1, wherein a hollow space is formed between the upper and lower elastomer sections, which space is filled with a gaseous medium, air, or an elastomer having a significantly lower Shore hardness than the elastomer in the elastomer section.

9. The self-adjusting joint according to claim 1, wherein the inner cylinder comprises a receiving space for receiving a receiving section of a chair leg.

10. An active dynamic chair having a base, at least one chair leg, and a seat which is mounted to the top end of the chair leg, wherein the bottom end of the chair leg is secured in a self-adjusting joint according to claim 1, which joint is located on the base.

11. The active dynamic chair according to claim 10, wherein three chair legs are provided between the base and the seat part and the bottom ends of the chair legs are each connected to the base at said self-adjusting joint, which joint is provided on the base.

Description

[0036] Other problems and advantages are illustrated by the description below and the drawings.

[0037] FIG. 1a is a perspective view of a known elastic conical compression joint.

[0038] FIG. 1b is a sectional perspective view of FIG. 1a.

[0039] FIG. 1c is an orthogonal cross sectional front view of FIG. 1a.

[0040] FIG. 2a is a perspective view of a first embodiment of a self-adjusting motion joint according to the concept of the present invention.

[0041] FIG. 2b is an orthogonal sectional view of FIG. 2a.

[0042] FIG. 2c is a cutaway front view of the connection of 2a, which is connected to a support member of a chair.

[0043] FIG. 3a is a sectional perspective view of FIG. 2a.

[0044] FIG. 3b is a sectional perspective view of a second embodiment of FIG. 2a.

[0045] FIG. 3c is a sectional perspective view of a third embodiment of FIG. 2a.

[0046] FIG. 3d is a sectional perspective view of a fourth embodiment of FIG. 2a.

[0047] FIG. 4 is a perspective view of an active dynamic chair using 6 self-adjusting joints.

[0048] FIG. 5 is a perspective view of an active dynamic chair or stool which uses a single self-adjusting motion joint on its base.

[0049] The invention is described in more detail below with reference to FIGS. 2 to 5, wherein the same reference symbols indicate same structural and/or functional features.

[0050] FIGS. 1a to 1c show an elastomeric joint 1 known from prior art. It has a hollow tubular inner cylinder 2 and an outer cylinder 3. The inner cylinder 2 provides a receiving space 6. The outer cylinder 3 is typically connected to, or configured with, a support base not shown in detail herein. Both cylinder bodies 2 and 3 are interconnected by an elastomer section 4 and an optional number of rigid cylinder bodies 5.

[0051] FIG. 1c clearly shows the conical gradation of the multiple elastic sections 4. If an axial load (see axial arrow) is transferred into the hollow space 6 via a connecting member, the taper angle 8 is reduced and the elastomer section 4 is compressed and partially sheared off.

[0052] FIGS. 2a to 2c show a self-adjusting joint 11 according to the concept of the present invention. FIG. 2b and FIG. 2c show a two-part construction of two conically graded compression spring sections 11a and 11b (shown herein as identical for the sake of simplicity).

[0053] The inner tubular cylinder body 12 (hollow cylinder with a round cross sectional area) provides a receiving space for a chair leg and has a substantially cylindrical inner wall with an inner diameter which remains constant between the top compression spring section 11a and the bottom compression spring section 11b.

[0054] As is clearly apparent from the figures, the inner cylinder 12 has a wall of different wall thicknesses, wherein the wall thickness initially decreases in the embodiments according to FIGS. 2B, 2C, 3A, and 3B from an upper end 12o until the top compression spring section 11a ends in the vertical direction where it is fastened to the inner cylinder 12.

[0055] A hollow space 25 is located between the top compression spring section 11a and the bottom compression spring section 11b, which space is either filled with a medium such as air or with an elastomer 27 as shown in FIG. 3B.

[0056] The self-adjusting joint 11 further comprises an outer cylinder 13 (formed of a rigid material). The rigid inner cylinder 11 and the rigid outer cylinder 13 are interconnected, respectively, by two parts, i.e. spatially separated top and bottom elastomer sections 14a and 14b.

[0057] The elastomer sections 14a and 14b are each further divided by rigid hollow tubular cylinder bodies 15a and 15b, which are arranged like onion skins relative to each other. Therefore the cylinder bodies 15a, 15b located farther inwards have a smaller diameter than the cylinder bodies 15a, 15b located farther outwards. In a preferred embodiment of the invention, the radial distances of the respective hollow cylinder bodies 15a or hollow cylinder bodies 15b are about the same, such that an approximately equidistant arrangement of cylinder bodies results when viewed in the radial direction. One elastomer is annularly inserted between each of the adjacent cylinder bodies 15a and 15b. When viewed in the radial direction with respect to the central axis through the inner cylinder 11, the upper and lower edges R of the cylinder bodies 15a or 15b located farther outwards are arranged at an offset in the vertical direction with respect to the cylinder bodies 15a or 15b located farther inwards in the representation, such that the joint 11 has an outwardly conically downward sloping lid structure, which in the normal state (i.e. without a force being applied via a chair leg 21) defines a tangential plane through the upper edges of the cylinder bodies 15a or 15b, respectively, which plane is tilted by the tangential angle 20 with respect to a horizontal plane.

[0058] The conical compression spring sections 11a and 11b have a height 17a and 17b, respectively, (which can be same or different depending on the desired spring characteristic), a width 19, and a diameter 22.

[0059] As is further well apparent in the figures, the inner cylinder 12 has a wall with increasing wall thickness in the axial direction in the region between the top and bottom compression spring sections 11a, 11b, namely where these are connected to the inner cylinder 12.

[0060] The wall thickness then decreases again in the region of the bottom compression spring section 11b.

[0061] FIG. 2c shows the joint 11 with an elongate support member 21 (here, a chair leg), the connection area 21a of which is non-positively and positively locked in the receiving space 16. If a transverse force is applied to the upper part of the support member 21, as indicated by the double arrow 23, the pivot point 24 (defined between the top and bottom spring sections 11a and 11b) is formed and a tilting movement of the support member 21 is performed.

[0062] Since the support member 21 is mounted in two bearing areas (an area between the top scoring section 11a on the one hand and an area between the bottom spring section 11b on the other), the support member 21 can be tilted.

[0063] If an additional axial load 22 is applied to the support member 21, the compression spring sections 11a and 11b are partially lowered and thereby laterally compressed and vertically sheared in relation to each other, whereby the tilt stiffness of the support member 21 is automatically increased without the seat user having to adjust the characteristic manually to his or her weight.

[0064] All dimensional and material parameters determined may be used to adjust the characteristic of the self-adjusting motion joint 11. For example, an elastomer with a higher hardness may be used to achieve a higher overall stiffness of the joint.

[0065] The number of the rigid cylinder bodies 15a, 15b may also be increased to increase tilt stiffness without impairing axial attenuation. An increased height of each spring section increases both inclination and axial stiffness. An increased width of each spring section reduces axial stiffness. An increased distance between the spring sections increases tilt stiffness but does not impair axial stiffness.

[0066] This last point indicates the reason for a two-part design of the self-adjusting motion joint: While the height of a spring section increases both inclination and axial stiffness, the distance between the spring sections only increases the inclination of the slope but not the axial stiffness.

[0067] FIG. 3a is a sectional perspective view of the joint 11, which is shown here for reference to illustrate alternative embodiments. The space 25 between the top and bottom compression spring sections is filled with air.

[0068] FIG. 3b shows a similar self-adjusting motion joint 11, wherein the space between its top and bottom compression spring sections is filled with an elastomer 27 of low hardness.

[0069] FIG. 3c shows another self-adjusting joint 11 with a harmonized group of rigid tubular and hollow cylinder bodies 29, which connect the top and bottom compression spring sections to each other. The respective space 30 between the top and bottom compression spring sections 11a, 11 b is configured as a hollow space. The height of the cylinder bodies 29 decreases in this embodiment viewed from the inside to the outside.

[0070] In FIG. 3d, these hollow spaces 30 are filled with an elastomer 32 of sufficiently low hardness.

[0071] FIG. 4 shows an active dynamic chair 33 having a base 34 and seat 35 which are by three legs 36 to each other using 6 self-adjusting joints 11 (as described above). Each of the self-adjusting joints 37 allows a respective tilt, torsion, and axial load (depending on the weight of the seat user). FIG. 5 shows a pendulum stool 38 having a base 39 and a seat 40, both connected to each other by a single leg 41. The seat 40 has a rigid connection 42 with the chair leg 41. The base 39 is provided with a self-adjusting elastic joint 11 to allow pendular movement of the leg 41 and thus of the seat 40.

[0072] As is apparent from FIGS. 4 and 5, the lower edge R of the outer cylinder 13 of the respective joint 11 is mounted onto the base 34 or 39, respectively, and fastened there. Also conceivable is an embodiment in which the lower edge 13u of the outer cylinder 13 is formed axially opposite the connecting section to the bottom compression spring section 15b, such that the center of the joint 11 can dive deeper for seat users with a high body weight before the lower edge 112u of the inner cylinder comes to rest on the base 34 or 39, respectively.

[0073] A cylindrical adapter element would be conceivable which is mounted as a spacer to the bottom side of the joint 11.

LIST OF REFERENCE NUMERALS

[0074] 1. Elastomeric joint from prior art [0075] 2. Inner cylinder (configured as a hollow cylinder) [0076] 3. Outer cylinder (configured as a hollow cylinder) [0077] 4. Elastomeric intermediate areas [0078] 5. Rigid intermediate cylinder bodies [0079] 6. Receiving space [0080] 7. Width of the elastic area formed of elastomeric intermediate areas [0081] 8. Taper angle [0082] 9. Diameter of the elastomeric joint [0083] 10. Height of the elastomeric joint in the region of the outer flange [0084] 11. Self-adjusting joint with conically offset compression spring sections 11a and 11b [0085] 12. Inner cylinder [0086] 12o Upper edge of the inner cylinder [0087] 12u Lower edge of the inner cylinder [0088] 13. Outer cylinder [0089] 13o Upper edge of the inner cylinder [0090] 13u Lower edge of the inner cylinder [0091] 14a Elastomer sections [0092] 14b Elastomer section [0093] 17a,b Height of the tapering compression spring sections 11a,11b [0094] 18. Diameter [0095] 19. Width [0096] 20. Taper angle [0097] 21. Elongate support member of a chair [0098] 22. Axial load applied via the support member 21 to the joint 11 [0099] 23. Torque applied to the support member 21 [0100] 24. Pivot point for the tilting movement of the support member 21 [0101] 25. Hollow space/intermediate space between the top and bottom compression spring sections 11a and 11b [0102] 27. Elastomer Cylinder body [0103] 30. Hollow spaces [0104] 32. Hollow spaces filled with elastomer [0105] 33. Active dynamic chair [0106] 34. Base of the chair [0107] 35. Seat of the chair [0108] 36. Legs of the chair [0109] 38. Pendulum stool [0110] 39. Base of the stool [0111] 40. Seat of the stool [0112] 41. Legs of the stool [0113] 42. Connection