The present invention is related to a chair mechanism for biased tilting movement between the seat and the base column, connected respectively with the seat portion and the frame of the chair mechanism.

Throughout the passed years tilting mechanisms or chair mechanisms comprising torsion springs, have been used extensibly especially for office chairs and such and also have proved to be satisfactory with their small dimensions, simplicity in adjust¬ ment and good reliability. Partly this is achieved by a recti¬ linear torsion spring, usually clamped in both ends which then can be turned in relation to each other and the spring being surrounded by pipes.

With the present invention is found that this structure can be substantially simplified and especially the same advantageous are achieved by use of only one pipe, as defined by the features stated in the claim.

The drawing discloses in Fig. 1 schematically the chair mechanism according to the present invention in a top view, Fig. 2 discloses a front view, Fig. 3 discloses a ground view and Fig.

4 discloses a side view of the chair mechanism according to the present invention.

A torsion spring 1 having a square cross section, is arranged within and at both ends secured to a pipe, respectively

5 and 6. One of the pipes 6 is connected with a stop arm 7 abutting against a seat mount 2. By a means of a suitable grip the spring pressure of the torsion spring can be adjusted between the mount 2 and the arm 7. The other pipe 5 is directly connected with the frame 3 mounted to the column 4 of the chair. The seat mount 2 is arranged to be journalled around the other pipe 5.

The force path is according to the above described details, to be found from the seat mount 2, through the arm 7 and to the pipe 6, further from hear through the torsion spring 1 to the other pipe 5 and to the column or fundament of the chair through the frame 3.