| 摘要 |
One of two arms is mounted adjacent one end thereof for rotation and axial adjustment on a cylindrical column which projects vertically upwardly from a generally flat, rigid base. The second arm is rotatably connected adjacent one end to the opposite end of the first arm, and has mounted in its opposite end a rotatable spindle which is connected at its upper end to the drive shaft of a reversible electric motor that is secured on the second arm, and which is disposed to have a tool bit secured releasably to its lower end. The first arm is manually adjustable vertically on the column, and each arm can be releasably locked against rotation. The direction of rotation of the motor can be reversed by a switch mounted on the second arm and its speed can be adjusted by a potentiometer, the rotatable handle of which is mounted on the second arm adjacent the motor reversing switch. |
