| 摘要 |
A portable electric tool has a switching device for reversing the direction of the current through the motor to reverse the motor. The switching device comprises two pairs of contacts which extend in cantilever fashion from a circuit board, a rotatable shaft having axially spaced apart terminals thereon, and the terminals being electrically insulated from the contacts by insulating collars secured to the shaft. Each collar has a window therein for access to the respective terminal, the contacts being resiliently biased against the collars with one of each pair of contacts engaging a respective terminal through the respective window in one direction of rotation of the motor and the other of each pair of contacts engaging the opposite respective terminal through the respective window in the opposite direction of rotation of the motor. A shoulder on the shaft may have flats to prevent rotation of the shaft while the trigger of a trigger-switch is actuated.
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