Restraint system tensioning device with load limiting capability

An apparatus comprising a tensioning device (116) for an occupant restraint, the tensioning device comprising a tensioning member (122) which is connected with the occupant restraint in a manner such that the tensioning member is moveable in a first direction (124) to tighten the occupant restraint about an occupant and a second direction when the occupant loads the occupant restraint, the tensioning member comprising a piston supported for movement in a cylinder in the first and second directions, the tensioning device including an array of braking members (130) disposed between the piston and the cylinder, the piston and the braking members configured to cause the braking members to be forced into engagement withn the cylinderand to provide controlled slippage between the piston and the cylinder when the piston moves in the second direction;

• wherein the array of braking members comprises first and second braking members, (130a, 130b) which provide different levels of braking force between the piston and the cylinder when the piston moves in the second direction.