Abstract: A track assembly for a motor vehicle seat, the track assembly comprising a male track and a female track. An internal space extends longitudinally between the male track and the female track. The cross-section of the internal space varies along the longitudinal axis of the track assembly. A seat equipped with such a track assembly.

Abstract: A vehicle seat comprising a rigid support structure provided with a rear central beam, which structure carries a headrest, a seat proper, and a seat back carried by the central beam. The seat back is pivotally mounted on the central beam via two couplings that enable the seat back to move rearwards, under a force greater than a predetermined limit value.

Abstract: A vehicle seat comprising a seat back pivotally mounted on a seat proper to pivot about a transverse horizontal axis of rotation, the seat proper having a rigid framework which carries flexible padding and on which a support member is movably mounted to move vertically, the support member being adapted to form an abutment preventing the user of the seat from plunging into the padding downwards and forwards when the seat is subjected to high forward deceleration. The seat further comprises a coupling device connected to the support member and adapted to raise said support member when the seat back pivots backwards, and to lower the support member when the seat back pivots forwards.