Pyrotechnical drive device for safety-belt tightening devices

摘要

In the case of a pyrotechnical drive device for safety-belt tightening devices having a piston which is axially displaceable in a cylinder, is driven by means of an explosion and tightens the safety belt via a tensioning element when it is displaced longitudinally, a piston-braking device is provided to prevent accidents and injury in the case of malfunction. To enable the length of the drive device to be short, the cylinder is open at its rear end face, in the direction of displacement of the piston, to allow the piston to emerge, and the piston-braking device is arranged outside the cylinder in such a way that it commences operation when the piston starts to emerge from the cylinder.