US Patent 7287815 Ergonomic seating module and seat fitted with said module

The incentive seating module comprises: a structural frame provided with a gaiter, a frame, disposed above said structural frame and provided with an arch, whereby the structural frame exhibits planar symmetry, means for connecting the frame to the structural frame comprising a joint enabling the frame to swivel in relation to the structural frame about an axis which is perpendicular to the symmetrical plane, and a seating element joining the frame to the gaiter, made of an elastic membrane which is used to define a rest position for the frame in relation to the structural frame and to return it towards said position when a user causes it to tilt in one direction or the other.