Drive device for automobile adjustable component e.g. headrest, has pyrotechnic charge detonated for displacement of piston of piston-cylinder setting device

摘要

The drive device (10) is operated in a crash situation for movement of the automobile component from its normal operating position into a safety position via a pyrotechnic charge (20) detonated for axial displacement of a piston (14) provided with a projecting piston rod (28). The internal surface of the cylinder (12) enclosing the pison has a widened section over a given axial length, the outer surface of the piston rod or the piston has a reduced cross-section region (50) over a given axial length and/or the piston is provided with a blind bore (46) extending from its end face (26), communicating with a transverse bore (48) fed out from the piston rod.