| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent the pressing failure of a striking piston caused by abrupt rise of the internal pressure of a blowback chamber just before the landing of piston on a bumper. SOLUTION: In this pneumatic tool, compressed air is supplied from the upper end of a striking cylinder 2 to move the striking piston 4 for striking, after which a driver bit 3 connected to the lower portion of the piston 4 is rotated to drive a drive screw into a member for driving the screw therein. A small diameter part 20 which fits into the center hole 27 of the bumper 21 formed in the inner bottom of the cylinder 2 is formed at the lower portion of the piston 4, and an exhaust part A for allowing air below the cylinder 2 to escape into the atmosphere when the small diameter part of the piston 4 fits into the central hole 27 of the bumper is formed at either the lower portion of the piston 4 or the bumper 21.
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