Patent ID: 7455036

Claim:
A combustion-type power tool comprising: a housing having one end and another end; a head portion disposed at the one end; a cylinder disposed in the housing; a push lever disposed at the another end and movable in a longitudinal direction of the housing when pressure contacting a workpiece; a piston reciprocally movable in the cylinder; a combustion-chamber frame disposed in the housing and movable in the longitudinal direction in interlocking relation to the push lever, the combustion-chamber frame being abuttable on the head portion to provide a combustion chamber in cooperation with the head portion and the piston; a fuel supplying portion containing fuel and supplying the fuel into the combustion chamber, thereby providing air-fuel mixture in the combustion chamber; a motor disposed at the head portion and having an output shaft protruding into the combustion chamber; a fan disposed in the combustion chamber and connected to the output shaft so as to be rotatable with the output shaft for promoting turbulent combustion of the air-fuel mixture, the fan and the combustion-chamber frame defining, within the combustion chamber, a high turbulent-combustion region in which the turbulent combustion is rapidly generated and a low turbulent-combustion region outside the high turbulent-combustion region; a fin having one shape and disposed at at least one of the combustion-chamber frame, the head portion, and the piston so as to protrude into the combustion chamber, an entirety of the fin being located within the low turbulent-combustion region; and another fin having another shape different from the one shape, at least a part of the another fin being located in the high turbulent-combustion region. wherein the fin having one shape is disposed above the blade of the fan.