Patent attributes
Synchronisation mechanism for chairs or armchairs, of the type provided with a base (1), on which at least one seat frame (2) and at least one backrest frame (3) are hinged, at least one stiffening spring (4) positioned between the base and the backrest frame, in addition to a device for adjusting the stiffness of the above-mentioned spring comprising means (5, 6, 7, 8, 9, 10) to move one end (15) of the spring with respect to its other end (16). The above-mentioned means to move one end of the spring with respect to its other end comprise at least one cam element (5) hinged (6) to the base, so that the cam element acts, directly or indirectly, on the end (15) to be moved of the spring, the other end (16) of the spring being linked to the backrest frame.
