Chair having a tiltable seat

Chair having a tiltable seat carrier (1) and a tiltable backrest (2) supported by a backrest carrier (5), in which there is provided on the underside of the seat carrier (1) a bearing block (10) in which a rod (8) having a lifting element (7) is mounted vertically movably, this rod also being mounted at the other end in a bearing (6) on the backrest carrier (5),

• the bearing block (10) having a vertical slot (13) and a slideway contour (14), and
• the lifting element (7) being connected to the rod (8) by way of a flange (9), which is mounted vertically movably in the slot (13), and having a collar (12),
• characterised in that
• the slideway contour (14) has the shape of a rectangle with four straight sides which are connected to one another by way of rounded corners, one side running parallel to the slot (13) and the other side running horizontally above the slot (13), and
• the collar (12) has the shape of an equilateral triangle with three straight sides which are connected to one another by way of rounded corners, the flange (9) being seated in a corner of the triangle, and this rounded corner of the collar (12) lying in the front upper corner of the slideway contour (14) when the flange (9) is in the upper position and in the front lower corner of the slideway contour (14) when it is in the lower position, and the corners of the collar (12) being supported on the slideway contour (14) as the flange (9) moves up and down.