Patent ID: 7237515

Claim:
A combustion-type power tool comprising: a housing having one end and another end; a cylinder head disposed at the one end; a cylinder disposed in and fixed to the housing, the cylinder defining an axial direction; a piston slidably disposed in the cylinder and reciprocally movable in the axial direction; a push lever disposed at the another end of the housing and movable in the axial direction upon pressing against a workpiece; a combustion chamber frame disposed in the housing and movable in the axial direction, the combustion chamber frame comprising; a base section associated with the push lever, and having one end which is a remote side from the push lever; a head section fixed to the one end of the base section and abuttable on the cylinder head, the head section including a disc like connecting portion having a radially outer edge connected to the one end of the base section and having a radially inner edge, and a sleeve like abutment portion extending in the axial direction from the radially inner edge toward the cylinder head and abuttable on the cylinder head to provide a combustion chamber in cooperation with the cylinder head and the piston; a driver blade extending in the axial direction from the piston toward the another end of the housing; an ignition plug exposed to the combustion chamber for igniting a mixture of air and the combustible gas in the combustion chamber; and a fan rotatably disposed in the combustion chamber for agitating and mixing the air with the combustible gas, the fan including fan blades which define a widthwise center line in the axial direction, the widthwise center line being offset from the connecting portion in the axial direction and toward the piston in a non-operational phase; wherein each of the fan blades has a widthwise edge at a side of the cylinder head in the axial direction, and the widthwise edge is positioned coincident with the connecting portion in the non-operational phase.