Seat articulating device

Abstract: The invention concerns a seat articulating device comprising a seat and a back capable of pivoting relative to the back seat about a pivot pin (A1) into a plurality of positions, in particular a nominal position wherein the back is substantially vertical and a shelf position wherein the back is folded down on the seat, said device comprising: a flange (3) designed to support the back pivoting relative to the pivot pin (A1) including arc-shaped teeth having a radius R centered on the pivot pin (A1); a concave toothed segment (12) capable of being linked to the seat, oscillating relative to a pivot pin (A2) between a locking position wherein it co-operates with the teeth of the flange (3) and an unlocking position wherein it is spaced apart from the flange teeth and allows the flange (3) to rotate. The invention is characterized in that it comprises: a projecting part (6) of the flange surface (3) forming an arc-shaped ramp (7) centered on the pivot pin (A1) having a radius r smaller than the radius R of the teeth wherein is provided a groove (8), and an oscillating lever (23) located in the same plane as the projecting part (6) of the flange (3), coaxial and superimposed to the toothed segment (12) including a tooth (27) capable of sliding on the ramp (7), when the back pivots between the nominal position and the shelf position and capable of being locked in the groove (8) of the projecting part when the seat is in the shelf position. (end of abstract)