Actuating device for a safety means

An assembly comprising a safety means and an actuating device, said actuating device comprising a drive and a pyrotechnical gas generator for, when actuated, actuating said drive, said safety means including a safety belt, which in a fastened condition is attached to at least three points of attachment in a vehicle, said drive engaging two of said points of attachment and tensioning, said safety belt in a case of restraint, said drive comprising a radially expandable, tubular body, said tubular body longitudinally contracting upon radial expansion of said tubular body to tension said safety belt.