| 摘要 |
<p>A magnet base drill unit having a finger thereon frictionally engaging the surface of the workpiece to which the base of the drill unit is magnetically adherred. The finger is movable in response to lifting or sliding of the energized magnet base from the support base of the workpiece to actuate a switch for de-energizing the drill motor. The unit also includes a pointed punch adjacent the rear end of the magnet base which can be in one form of the invention impacted into the workpiece support surface either by a manually operated lever or automatically whenever the drill spindle is retracted from the work to a position near the upper end of its stroke. A second punch may be located on the drill unit rearwardly of the automatically actuated punch. The second punch is arranged to be embedded into the support surface of the workpiece by a manually applied hammer blow.</p> |
