Patent ID: 7014089

Claim:
A pneumatic tool comprising a circular cylinder, a piston slidably accommodated in said circular cylinder, a driver blade integrally fanned with said piston, and a sleeve valve portion for driving said piston when compression air is discharged from a sleeve valve chamber via a trigger valve portion, wherein said trigger valve portion father comprising: a plunger shifting in response to a trigger operation by a user; a valve piston slidably supporting said plunger and shifting in a direction opposed to a shifting direction of said plunger; and a valve bush slidably supporting said plunger and said valve piston so as to allow slide movements of said plunger and said valve piston, and a seal member provided on a first surface formed on one of said valve piston and said plunger; and combined grooves and ridges formed on a second surface formed on another one of said valve piston and said plunger, said grooves and ridges being alternately arranged along a circumferential direction of the other one of said valve piston and said plunger, said second surface opposing to said first surface, wherein said ridges hold said seal member and prevent said seal member from pulled off from the first surface formed on said one or said valve piston and said plunger and at the same time said grooves cooperatively define an air passage between said valve piston and said plunger.