Combustion chamber arrangement in combustion type power tool

A combustion-type power tool comprising:

• a housing having one end and a lower side;
• a head section closing the one end of the housing and formed with a combustible gas passage;
• a push lever provided to the lower side of the housing and movable upon pushing onto a workpiece;
• a cylinder secured to an inside of the housing;
• a piston slidably disposed in the cylinder and reciprocally movable in an axial direction of the cylinder, the piston dividing the cylinder into an upper cylinder space above the piston and a lower cylinder space below the piston;
• a combustion-chamber frame provided in the housing and guidedly movable along the cylinder, the combustion-chamber frame having one end abuttable on and separable from the head section in interlocking relation to the movement of the push lever, a combination of the combustion-chamber frame, the head section and the cylinder space above the piston defining a combustion chamber;
• a motor disposed at the head section;
• a fan rotatably positioned in the combustion chamber and driven by the motor;
• and
• an ignition plug provided at the head section and exposed to the combustion chamber;
• wherein the combustion-chamber frame has a specific section and a remaining section other than the specific section, and a distance between an axis of the fan and an inner wall of the specific section in a plane perpendicular to the axis being greater than a distance between the axis of the fan and an inner wall of the remaining section in the plane, the specific section ranging from −30 to 150 degrees about the axis of the fan relative to a connection line connecting between the axis of the fan and the ignition plug in a rotational direction of the fan.