To provide a fastener driving device having a bumper having advantages of standing a collision of a piston in an upper part and improving absorption of energy at the time of the collision of the piston in a lower part.
This bumper 11 having a vertically long cylindrical shape extending in the shaft direction and formed with a through hole is stored in a cylindrical storing part 14 provided in a lower part 22 of a cylinder 2 and an upper part 23 of a nose 10. The bumper 11 is formed into a cylindrical shape of an outer diameter slightly smaller than an inner diameter of the storing part 14 in the upper part 17 abutting on a lower face of the piston 3, and is formed into a prism shape of a polygonal shape having polygonal cross section inscribing an inner peripheral surface of the storing part 14 to form a prescribed gap 25 between an outer periphery of the bumper 11 and an inner periphery of the storing part 14 in the lower part 18 adjacent to the upper part 23 of the nose 10.
ISHIKAWA NAOHARU
Fumiaki Otsuka
Takaki Nishijima
Hiroyuki Suda