Abstract: The device comprises a drum around which a belt is wound under the action of a return spring. This spring acts through a cable passing around two pulleys of variable diameter which produce a return force which is independent of the extent of the winding of the belt. Moreover, the cable passes around a pulley which permits transmitting to a device responsive to acceleration a value which represents the linear acceleration of the belt which is also independent of the extent of the winding of the belt.

Abstract: The vehicle seat has a seat base and a backrest pivotable relative to the seat about an axis transverse to the direction in which the seat is longitudinally adjustable in position. A link pivoted at one end to the seat base front part and at the other end to the floor of the vehicle and a shoe connected to the seat base and adjustable in position on a slideway secured to the floor of the vehicle allow said longitudinal adjustment of the seat. The shoe is connected to the seat base by an intermediate member pivoted to the shoe and connected to the seat base to pivot about said axis. Locking and unlocking means releasably lock the intermediate member relative to the seat base.