Patent ID: 8602283

Claim:
A gas combustion type driving tool comprising: a combustion chamber; a hammering cylinder; a hammering piston contained in the hammering cylinder; a nose part for guiding a driver connected to a lower face side of the hammering piston; a feed cylinder; a feed piston contained in the feed cylinder and having a feed claw engaged/disengaged to/from a connecting fastener contained in a magazine; a gas pipe which is provided between the combustion chamber and the feed cylinder and through which part of a combustion gas is supplied to the feed piston; and a check valve, wherein the feed piston is constantly urged in a fastener feed direction by a spring, wherein upon supply of a combustion gas to the feed cylinder from the gas pipe, the feed piston is operated in a retracting direction against the spring, wherein a combustion gas filter for cooling and increasing the combustion gas in density is provided in the gas pipe so as to supply the combustion gas to the feed cylinder without reducing a pressure of the combustion gas, the combustion gas filter including an upstream filter provided upstream of the check valve; and a downstream filter provided downstream of the check valve, and wherein the feed piston is held at a retracted position by the cooled combustion gas until the completion of return of the hammering piston.