| 摘要 |
A driver drill that can effectively prevent erroneous clutch operation in a drill mode is provided. A flat washer (48) positioned between steel balls (54, 54) for locking an internal gear (17) and a coil spring (53) is rotatable by rotative operation of a mode-change ring (39). Also, protruding streaks (52, 52) are provided on a small-diameter unit (14) of a second gear case (12) around which a flat washer (48) is externally mounted. The protruding streaks (52, 52) interfere with internal projections (50, 50) on an inner circumference of the flat washer (48) at its predetermined rotating position to regulate a forward movement of the flat washer (48). When a drill mode is selected with the mode-change ring (39), the flat washer (48) is locked by the protruding streaks (52, 52). |
