Patent ID: 8574115
Filing Date: 2013-11-05
Classification: B25F

Abstract:
1. An electric power tool including a motor accommodated in a housing and serving as a drive power source; a speed reduction mechanism for transferring a rotational driving force to a tool part provided at a front side of the housing; and a cylindrical reducer case, accommodated in the housing and accommodating therein the speed reduction mechanism, wherein the speed reduction mechanism includes a planetary gear train and a movable member which is slidable in an axial direction of the planetary gear train to be engaged with or disengaged from the planetary gear train, and a reduction ratio thereof is changeable at a plurality of stages by controlling the movement of the movable member, the electric power tool comprising: the reducer case including a slide hole formed through a sidewall of the reducer case and extended along the axial direction; a rotary plate which is rotatable around a periphery of the reducer case about the axis, the rotary plate including an operation slot formed obliquely with respect to the axial direction and overlapped with the slide hole and a biasing unit; a supporting member radially outwardly protruded from the movable member and extended through the slide hole and the operation slot; and a driving unit configured to drive the rotary plate along the periphery of the reducer case, wherein the biasing unit applies a pressing force to the supporting member in a moving direction of the supporting member when the rotary plate is rotated to a position by the driving unit.