Drill bit

Abstract

A drill bit, the frame of which comprises a front section with protrusions. A set of first rear teeth is arranged at the front section, preferably at the rear part of the protrusions. The set of first rear teeth broadens a drilled hole when the drill is reversed.

1 . A drill bit, the frame of which comprises a front section with protrusions, the front section being provided with a set of first rear teeth, and a rear section which is provided with second protrusions which are arranged to improve guiding of the drill bit, the rear end of the second protrusions being provided with a set of second rear teeth.  
     
     
         2 . A drill bit as claimed in    claim 1   , wherein the distance between the set of first rear teeth and the face of the drill bit is shorter than the diameter of the front section of the drill bit.  
     
     
         3 . A drill bit as claimed in    claim 2   , wherein the distance between the set of first rear teeth and the face of the drill bit is smaller than 0.5 times the diameter of the front section of the drill bit.  
     
     
         4 . A drill bit as claimed in    claim 1   , wherein the set of first rear teeth is arranged at the rear part of the protrusions.  
     
     
         5 . A drill bit as claimed in    claim 1   , wherein the diameter of the drill bit front section measured at the protrusions is larger than the diameter of the other parts of the frame of the drill bit.  
     
     
         6 . A drill bit as claimed in    claim 1   , wherein the drill bit comprises a middle section and a rear section and the rear section comprises a second set of protrusions such that the diameter of the rear section measured at the second set of protrusions is larger than the diameter of the middle section of the drill bit, but smaller than the diameter of the drill bit front section measured at the protrusions.