Patent ID: 7021251
Filing Date: 2006-04-04
Classification: B25C

Abstract:
1. A combustion-type power tool comprising: a housing having an inside, one end, and a lower side; a handle extending from the housing and provided with a trigger switch; a head section closing the one end of the housing and formed with a combustible gas passage; a motor attached to the head section; a push lever provided to the lower side of the housing and movable upon pushing onto a workpiece; a cylinder secured to the inside of the housing and formed with an exhaust hole; a piston slidably disposed in the cylinder and reciprocally movable in an axial direction of the cylinder; 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 head section, the cylinder, the piston and the combustion-chamber frame defining a combustion chamber; a driver blade extending from the piston toward a side opposite to the combustion chamber; seal portions providing sealing relations between the combustion chamber frame and the head section and between the combustion chamber frame and the cylinder when the combustion chamber frame is brought into abutment with the head section; a fan rotatably positioned in the combustion chamber and connected to the motor; an ignition plug exposed to the combustion chamber for igniting a mixture of air and the combustible gas in the combustion chamber in response to operation of one of the trigger switch and the head switch; an exhaust check valve selectively opening the exhaust hole, the combustible gas being supplied into the combustion chamber through a combustible gas passage, and being explodingly combusted upon ignition of the ignition plug for moving the piston; a temperature detecting unit detecting a temperature associated with one of the housing and the handle; and an avoiding unit that avoids overheating to one of the housing, the handle, and components in the housing, the avoiding unit being connected to the temperature detecting unit for controlling operation of one of the ignition plug and the fan based on a temperature detected by the temperature detecting unit.