Patent ID: 7475752

Claim:
Safety device ( 1 , 101 , 201 ) for raising the bonnet ( 11 , 111 , 211 ) of a motor vehicle in the event of a collision with a pedestrian, comprising a pyrotechnic actuator ( 2 , 102 , 202 , 302 ) possessing a hollow body ( 16 , 116 ) containing a thrust piston ( 17 , 117 ) secured to a mechanism for raising the bonnet ( 11 , 111 , 211 ) and able to deploy the said mechanism which is itself secured to the said bonnet ( 11 , 111 , 211 ), a blocking device intended to block the said actuator ( 2 , 102 , 202 , 302 ) in a given position and a shock-absorbing device employed when a pedestrian hits the bonnet ( 11 , 111 , 211 ) which has been raised, so that the assembly consisting of the bonnet ( 11 , 111 , 211 ), the raising mechanism and the piston ( 17 , 117 ) can move under the effect of the impact while at the same time being retarded, characterized in that the hollow body ( 16 ) exhibits a small-diameter upstream part ( 18 ) and a larger-diameter downstream part ( 19 ) which parts are connected to one another by a divergent passage ( 20 ), and in that the piston ( 17 ) comprises a peripheral groove ( 23 ) partially delimited by the internal wall of the said upstream part ( 18 ), the said groove ( 23 ) housing a prestressed member bearing against the said internal wall.