Restraint system for a vehicle

摘要

A vehicle seat restraint system comprises a seatbelt spool 12 with a toothed pinion 20 arranged to tighten a seatbelt 14 when pretensioner device 18 is triggered. The pretensioner device 18 has pretensioner balls 22 which travel within a guide element tube 24 to engage with the toothed pinion 20. Protrusions 36a-c on the guide surface allow the balls 22 to pass toward the pinion 20 but restrict movement in the balls 22 away from the pinion 20 temporarily, at least. The protrusions 36a-c can be in the form of fins arranged diagonally to chock the balls when the seatbelt is extended; if sufficient force is applied the fins 36a-c will deform to allow the balls 22 to pass back past and so limit the load on the passenger. A pyrotechnic actuator 30 triggers the movement of the balls 22 along the guide tube 24 toward the toothed pinion 20.