Seatbelt pretensioner for vehicle seats

Vehicle seats are taught that comprise a cushion frame (10) having a pair of frame elements (12) and a cylindrical connector member (14) that interconnects the frame elements. At least one seatbelt pretensioning device (20, 40) preferably exerts a traction force on a seatbelt when the vehicle is subjected to an impact. The pretensioning device may include a drive force generating means (22, 42) and a movable member (26, 46). The drive force generating means and the movable member are preferably received within a cavity of the connector member. The movable member is preferably arranged and constructed to move along the connector member when the drive force generating means is actuated.