| 摘要 |
<p>An electric switch system for a DC motor powered power tool, comprising: a moveable block (20) which is adapted to be manually displaced between a first position and a second position for speed control of the motor; a fixed block arranged adjacent to the first moveable block; a manual selection lever (41) pivotally attached to the fixed block and adapted to be manually rotated from a neutral middle position to either side for the selection of the rotational direction of the motor; a cam structure for permitting the manual rotation of the manual selection lever in either direction away from the middle neutral position only when the moveable block is at the first position and keeping the angularly displaced state of the manual selection lever when the moveable block is displaced away from the first position. Thus, the selection of the rotational direction of the motor and the speed control of the motor can be accomplished as a continuous single operation, and the convenience of the power tool is improved. Further, since the composite control functions can be incorporated into a highly simplified integral unit, the manufacturing cost is reduced and the reliability of the system is improved.</p> |
