Patent ID: 8328059

Claim:
A gas combustion type driving tool comprising: a cylinder slidably accommodating a piston; a cylinder head provided above the cylinder; a cylindrical movable sleeve disposed movably in a vertical direction between the cylinder and the cylinder head and having a larger inner diameter than an outer diameter of the cylinder; and an annular sliding portion formed on an outer circumference of the cylinder and below an upper opening end of the cylinder and sliding with an opening portion at a lower end of the movable sleeve, wherein the outer circumference of the cylinder has at least a first outer circumferential portion entirely disposed at a height position below where the lower most outer circumference of the piston meets the inner circumference of the cylinder when the piston is at the top dead center, and a second outer circumferential portion located below the first outer circumferential portion, the second outer circumferential portion defined by a raised protrusion, the sliding portion is provided on the second outer circumferential portion, the outermost diameter of the second outer circumferential portion is larger than the outermost diameter of the first outer circumferential portion, and the cylindrical movable sleeve forms a combustion chamber above the upper opening end of the cylinder and around an outer periphery of the cylinder below the upper opening end of the cylinder and extending to the second outer circumferential portion.