Patent ID: 7455129

Claim:
A drilling and/or chiseling tool ( 4 ) for machining materials such as concrete, rock, and masonry, having a hard metal cutting element ( 1 ) situated at the machining end, a radially outer, second working region (II) of the hard metal cutting element ( 1 ) being set back in relation to a central, first working region (I) of the hard metal cutting element ( 1 ) and the two working regions (I, II) transitioning into each other via a third working region (III), wherein the third working region (III) is at least partially comprised of at least one partial circumference surface ( 5 , 6 ) of at least one conical and/or spherical surface (K), wherein the solid hard metal head ( 1 ) is mirror symmetrical in relation to a longitudinal axis (L) in all three working regions (I, II, III), wherein a main cutting edge ( 8 ) extends to the third working region (III) and is continued in it by an edge ( 8 ′), wherein said edge ( 8 ′) in turn transitions into a cutting edge ( 12 ) of the first working region (I), wherein the drilling and/or chiseling tool ( 4 ) is supported on the material to be machined and firmly contacts material to be machined over its entire surface ( 5 , 6 ) since the entire surface ( 5 , 6 ) remains in constant contact with the material to be machined and wherein the partial circumference surface ( 5 , 6 ) is delimited in the working direction (x) by edges (KO 6 , KU 6 ) that extend in arcs with varying curvatures.