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(11) | EP 0 316 574 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Electric switch system for a power tool |
(57) 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. |