Vehicle seat articulation mechanism and seat comprising such a mechanism

Vehicle seat articulation mechanism intended to connect two elements belonging to the seat, the articulation mechanism comprising first and second rigid cheek plates extending in parallel planes and intended to be attached respectively to the two seat elements, and an adjustment mechanism connecting the first and second cheek plates and suitable for allowing a relative angular adjustment between the said cheek plates. The first cheek plate is trapped against the second cheek plate by at least one rigid annular gusset which is welded against the inner face of the second cheek plate.