Patent ID: 6783045
Filing Date: 2004-08-31
Classification: B25C

Abstract:
A combustion-powered tool for driving a fastener into a workpiece, comprising:a housing having an upper end portion, a lower end portion, an inner surface, and an outer surface; a push lever supported at the lower end portion of the housing; a head cover disposed at the upper end portion of the housing; a cylinder fixedly disposed in the housing and formed with an exhaust hole; a piston slidably movably disposed in the cylinder and dividing the cylinder into an upper chamber and a lower chamber, the piston being movable toward its lower dead center and its upper dead center; a combustion chamber frame disposed within the housing and movable in interlocking relation with the movement of the push lever to bring into contact with and out of contact from the head cover, wherein a combustion chamber is defined by the combustion chamber frame, the head cover, and the piston when the combustion chamber frame is in contact with the head cover; a driver blade extending from the piston into the lower chamber, a fastener driving operation being performed by the driver blade in accordance with the movement of the piston toward the lower dead center; a spark plug exposed to the combustion chamber for igniting a fuel/air mixture provided in the combustion chamber; a first switch that is turned ON when the combustion chamber is detected to be hermetically sealed and OFF when the combustion chamber is detected to be open to atmosphere; a second switch that is turned ON when manipulated by an operator and OFF when manipulation by the operator is stopped; and a control unit for controlling the spark plug to ignite the fuel/air mixture when both the first switch and the second switch are turned ON irrespective of an order in which the first switch and the second switch are turned ON.