Patent ID: 8511947

Claim:
A cutting device comprising: a fixing plate defining a first through hole; a revolving cylinder threadedly engaged in the first through hole of the fixing plate, the revolving cylinder defining a second through hole; an annular cutting blade defining a third through hole, the cutting blade being attached to an end of the revolving cylinder with the third through hole thereof being coaxially aligned with the second through hole, wherein the revolving cylinder is rotatable relative to the fixing plate to move the cutting blade between an extended position where the cutting blade cuts a workpiece to create a round blind crack in the surface thereof, a portion of the workpiece being surrounded by the blind crack, and a retracted position where the cutting blade is moved away from the workpiece; and an ejection bar slidably engaged in the second through hole and the third through hole, the ejection bar configured for pushing the surrounded portion out of the workpiece.