Patent ID: 9114780
Filing Date: 2015-08-25
Classification: B60R

Abstract:
1. A piston for a pretensioner device ( 10 ) for a motor vehicle seat belt system, the pretensioning device of a type having a gas generator ( 17 ) with the piston ( 21 ) guided in a tube ( 16 ) that closes a pressure space ( 20 ) in the tube ( 16 ), whereas the pressure space ( 20 ) is pressurized by the gas generator ( 17 ), as a result of which the piston ( 21 ) is driven to undergo pretensioning operation which is transmitted to the seat belt system by a force transmission means, the piston comprising: the piston having a dome shaped front side adapted to engage a force transmission element and having a skirt forming a sealing lip adapted to be oriented toward the pressure space, at least one slot formed in the outer surface of the piston and through the sealing lip, the slot extending axially from the sealing lip along the outer surface, the piston having a material adjoining the slot that leads to an enlargement of the slot by material erosion caused by the pressure and/or pressure conditions in the pressure space produced by gas from the gas generator.