Patent ID: 6978919
Filing Date: 2005-12-27
Classification: B25C

Abstract:
1. A drive piston assembly for a setting tool, comprising a drive piston ( 8 ) having a circumferential adjusting surface ( 16 ) having a first section inclined toward a central axis ( 17 ) of the drive piston ( 8 ) so that a diameter of the first section increases toward the rear, with respect to a setting direction ( 18 ) of the setting tool, end of the drive piston ( 8 ), and a second section adjoining the first section and inclined toward the central axis ( 17 ) of the drive piston ( 8 ) so that a diameter of the second section diminishes toward rear, with respect to a setting direction ( 18 ) of the setting tool, end of the drive piston ( 8 ); a piston holder for holding the drive piston ( 8 ) in an ignition-ready position thereof and for decelerating the drive piston ( 8 ) during return of the drive piston ( 8 ) to the ignition-read position after completion of a drive-in process, the piston holder ( 8 ) having contact means ( 22 ; 24 ; 36 ; 40 ; 41 ; 52 ; 53 ; 58 – 61 ) engageable with the adjusting surface ( 16 ); first spring means ( 21 ; 27 ; 35 ; 36 ; 54 ; 55 ; 62 ) for biasing the contact means into engagement with the first section of the adjusting surface ( 16 ) in the ignition-ready position of the drive piston ( 8 ) and for biasing the contact means into engagement with the second section for decelerating the drive piston ( 8 ) during return of the drive piston ( 8 ) to the ignition-ready position; and second spring means ( 34 ) for axially biasing the contact means in a direction opposite the setting direction ( 9 ) against a stop surface.