Patent ID: 8083007

Claim:
An electric power tool comprising: a motor as a driving power source for generating rotational power; a speed reducer unit arranged to deliver the rotational power of the motor and provided with two or more gears; a driving unit arranged to deliver the rotational power from the speed reducer unit to a tip end tool; a housing arranged to accommodate the motor, the speed reducer unit and the driving unit therein and provided with a handle portion; and a speed changing unit for changing a gear reduction ratio of the speed reducer unit, the speed changing unit arranged in such a position as to be operable outside the housing, wherein the speed changing unit comprises an operation lever slidingly operable in a sliding direction when pushed, a power control unit for detecting that the operation lever is pushed by a threshold amount and changing electric power supplied to the motor when the operation lever is pushed by the threshold amount, a shift unit for changing the gear reduction ratio of the speed reducer unit in response to a sliding movement of the operation lever, and a slide restraint unit for restraining the sliding movement of the operation lever until the power control unit detects that the operation lever is pushed by the threshold amount, and wherein the slide restraint unit includes a projection portion provided in one of mutually facing surfaces of the operation lever and the housing and a guide portion provided in the other surface, the projection portion and the guide portion being configured in such a manner as to restrain the sliding movement of the operation lever in the sliding direction when the operation lever is in a non-pushed position but permit the sliding movement of the operation lever in the sliding direction when the operation lever is in a pushed position.