LOAD-LIMITING SEATBELT RETRACTOR

A restraint system includes a retractor housing; a spool rotatably coupled to the retractor housing and defining an axis of rotation; an inner torsion bar elongated along the axis of rotation and positioned coaxially in the spool; an outer torsion bar elongated along the axis of rotation, extending coaxially around the inner torsion bar, and positioned coaxially in the spool; an engagement member selectively engageable with the outer torsion bar; and a solenoid operable to move the engagement member into engagement with the outer torsion bar and out of engagement with the outer torsion bar.