Abstract: Device includes plates which are connected by an axle that extends through a guiding piece and a ball joint element positioned at the ends of a column tube. Rotating elements are disposed in the plates and enable same to rotate around the axle which is blocked in rotation by the guiding piece. The guiding piece has a concave spherical surface coupled to the convex surface of the eccentric which is equipped with a bore that is off-centre in relation to the vertical axis of the spherical surfaces and a flat surface which is perpendicular to the axis of the bore. An eccentric pivots in the bore and on the surface via a cylinder and a surface. The eccentric is equipped with a bore that is off-centre in relation to the cylinder. The combined reverse rotation of the eccentrics enables the assembly to pivot around the axis.