Patent ID: 6837411

Claim:
Fastening apparatus with indirect firing, by means of which a fastening element is driven into a support material under the action of propellent gases from an explosive charge via a piston ( 2 ) mounted so that it can move in a barrel ( 3 ), between a firing position and a fastening position, and a plug guide ( 5 ) in which a piston-braking ball ( 6 ) mechanism is mounted, exerting a radial force on the piston ( 2 ), and comprising means ( 7 ) arranged to modulate the radial force of the balls ( 6 ), depending on the relative displacement of the barrel( 3 ) and of the piston ( 2 ), between a maximal force when the piston ( 2 ) moves forward in the barrel ( 3 ), and a non-null minimal force when the piston ( 2 ) moves back, apparatus characterized by the fact that the balls ( 6 ) are restrained radially by clamping lever arms ( 7 ) for modulating the radial action of the balls ( 6 ), mounted so that they can pivot on the plug guide ( 5 ) under the force of the balls ( 6 ) rolling on the arms ( 7 ).