BELT PRETENSIONER FOR A VEHICLE SEAT BELT RETRACTOR

摘要

Belt Pretensioner for a Vehicle Seat Belt Retractor A belt pretensioner is provided for a vehicle safety belt system having a retractor from which and onto which a belt is arranged to be unwound and wound by rotation of a reel shaft. The pretensioner includes a pulley carrying a pulley gear and is ordinarily restrained in a position in which the pulley gear does not engage a shaft gear on the reel shaft and a pulling cable having a pulley engaging segment wound onto the pulley and having a pulling segment leading from the pulley in a pulling direction to a power source arranged to pull on the cable and translate the pulley to engage the pulley gear with the shaft gear and rotate the pulley such the gears rotate the reel shaft and pretension the belt by winding it onto the reel shaft. The pulling cable has a pulled segment leading away from the pulley-engaging segment from the end thereof opposite the pulling segment in a direction substantially aligned with the pulling direction. A portion of the pulled segment frictionally engages fixed braking surfaces on the retractor. The pulley is restrained by the pulling and pulled segments of the pulling cable in a position in which the gears are not engaged. 1390