| 摘要 |
A device for changing the rotation of a drill from a forward to a reverse direction which comprises a drill, an AC single-phase motor operatively connected to the drill for driving the same, a circular measuring plate connected to the drill, the circular measuring plate having a handle, and a groove disposed on the periphery of the plate, and a microswitch containing electrical terminals and being operatively connected to the motor, the microswitch containing a bar which is pivotally disposed to engage and disengage the microswitch, the bar having a spring biased arm which extends from the microswitch to slidably engage and rotate with the periphery of the measuring plate, whereby when the handle of the measuring plate is rotated in the left or right direction, the bar of the microswitch is caused to move in a corresponding upward or downward direction along the periphery of the measuring plate, until it engages the slot whereby the direction of rotation of the motor is reversed. |
