A chair base, a chair frame and a chair

Abstract

A chair base includes a central opening configured to receive and support a post essentially vertical in an operating position of the chair base, and at least three, preferably five, arms which project radially from the opening. At least one of the arms has a substantially U-shaped profile or a substantially O-shaped profile along its longitudinal direction starting from an outer arm end, and the at least one of the arms also has a substantially I-shaped profile or a substantially T-shaped profile along the longitudinal direction which differs from the U-shaped profile or O-shaped profile.

1 . A chair base for a chair, the chair base comprising:
 a central opening configured to receive and support a post which is essentially vertical in an operating position of the chair base, and   at least three, preferably five, arms which project radially from the opening, wherein at least one of the arms has a substantially U-shaped profile or a substantially O-shaped profile along its longitudinal direction starting from an outer arm end,   wherein the at least one of the arms also has a substantially I-shaped profile or a substantially T-shaped profile along the longitudinal direction which differs from the U-shaped profile or O-shaped profile.   
     
     
         2 . The chair base according to  claim 1 , wherein the I-shaped profile or the T-shaped profile has, in the operating position, a substantially vertically aligned web and a lower flange and/or an upper flange. 
     
     
         3 . The chair base according to  claim 1 , wherein the I-shaped profile or 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 a vertical plane of symmetry through the I-shaped profile or the T-shaped profile. 
     
     
         4 . The chair base according to  claim 1 , wherein the lower flange and/or the upper flange has or have a concave, preferably V-shaped in the operating position, particularly preferably inverted V-shaped, indentation. 
     
     
         5 . The chair base according to  claim 1 , wherein the U-shaped profile is essentially inverted in the operating position, wherein legs of the U-shaped profile are essentially vertically aligned and wherein a side of the U-shaped profile arranged between the legs forms an upper side. 
     
     
         6 . The chair base according to  claim 1 , wherein the upper side of the U-shaped profile or an upper side of the O-shaped profile and the upper flange of the I-shaped profile or of the T-shaped profile merge into one another. 
     
     
         7 . The chair base according to  claim 1 , wherein a wall is arranged between the U-shaped profile or the O-shaped profile and the I-shaped profile 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 profile or T-shaped profile. 
     
     
         8 . The chair base according to  claim 1 , wherein the I-shaped profile or the T-shaped profile extends along the longitudinal direction over between 50 and 80%, preferably over between 60 and 70%, of a length of the at least one arm. 
     
     
         9 . The chair base according to  claim 1 , wherein the at least one arm has a support area at the outer arm end for supporting the chair base, preferably wherein the support area has a bearing opening, in particular in the form of a blind hole, for receiving an insertable extension, e.g. from castors. 
     
     
         10 . The chair base according to  claim 9 , wherein the support area has an outer wall closed circumferentially, preferably wherein stiffening struts are arranged between the bearing opening and the outer wall, in particular which are aligned radially to the bearing opening. 
     
     
         11 . The chair base according to  claim 9 , wherein the outer wall merges into the O-shaped profile or the U-shaped profile, in particular into the legs and the upper side of the U-shaped profile. 
     
     
         12 . The chair base according to  claim 1 , wherein the inner arm ends of the arms facing the opening form an area which is substantially concentric with the opening and has a reinforced double wall, preferably wherein the concentric area has radial stiffening struts which are preferably spaced apart from one another and/or is open at the bottom in the operating position. preferably regularly spaced stiffening struts and/or is open at the bottom in the operating position. 
     
     
         13 . The chair base according to  claim 12 , wherein an outer wall of the double wall merges into the I-shaped profile or the T-shaped profile, in particular into the web and the upper flange and/or the lower flange. 
     
     
         14 . The chair base according to  claim 1 , wherein the arms are formed separately from one another and are preferably connected to the opening and/or to one another. 
     
     
         15 . The chair base according to  claim 1 , wherein the chair base consists at least in part and/or proportionally, preferably completely, of plastic. 
     
     
         16 . A chair frame for supporting a seat, the chair frame comprising:
 the chair base according to  claim 1 ,   a post inserted into the opening, in particular a gas pressure spring, and   a connecting element attached to the post for attaching the seat.   
     
     
         17 . A chair, in particular office or work chair, comprising:
 the chair frame according to claim  16 ,   a seat attached to the connecting element, and   castors, stoppers, sliding elements or the like attached to the arms.