Patent ID: 7334646

Claim:
An electric power tool, comprising: a housing; a motor encased in the housing and having an output shaft producing a torque; a spindle provided at a front end of the housing, the spindle receiving the torque and capable of rotation; a gear unit provided between the output shaft of the motor and the spindle for transferring the torque to the spindle, the gear unit including a carrier, a first gear having a first diameter and a second gear having a second diameter that is different than the first diameter, the first and second gears revolving on inner peripheral surfaces of first and second internal gears, respectively; and a switchover mechanism for coupling the torque of the output shaft to the spindle, said switchover mechanism being slidably movable between a first position to rotate the spindle at a first speed, a second position to rotate the spindle at a second speed, and a third position to rotate the spindle at a third speed, wherein when the switchover mechanism is in the third position, the switchover mechanism engages both the carrier and the first internal gear while disengaging from the housing to integrate the first internal gear and the first gear with the carrier so that the spindle receives the torque without going through the first gear or the second gear.