Patent ID: 7325624

Claim:
A hammer drill comprising: a housing; a motor disposed in the housing and generating a rotational force; a working tool; a striking force transmitting mechanism comprising: a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having one end and another end, the working tool being engaged with the one end so as to be rotatable together with the cylinder; a piston disposed adjacent to the another end in the cylinder and movable in a reciprocating motion in the axial direction; a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston; and a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the reciprocating motion of the piston generating pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool; a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool; a switching mechanism that switches on and off transmission of the striking force to the working tool and that switches on and off transmission of the rotational force to the working tool, thereby switching operation modes among at least a rotation and strike mode, a strike only mode, and a neutral mode; and a rotation locking mechanism that engages the cylinder during the strike only mode, thereby locking rotation of the cylinder, wherein, during the neutral mode, the transmission of the striking force, the transmission of the rotational force, and the locking of rotation of the cylinder are all turned off.