Patent ID: 7900721

Claim:
A rock drill comprising: a hard metal plate inserted into a seat formed at one end of a drill shaft, said drill shaft having a radial dimension defining a first side and a second side of the drill shaft and an axial direction, and said hard metal plate comprising a substantially rectangular base shape having two opposed long sides extending in the axial direction of the drill shaft which are at least partially covered by the seat, two opposed, substantially axial free short sides, a radial bottom side facing towards the seat and a roof-shaped cutting face facing away from the seat, wherein both short sides are formed by an axial section having a purely axial direction component and a conical section inclined towards the axial direction, so that at the short side, the substantially rectangular plate tapers towards the bottom side wherein the hard metal plate protrudes radially beyond both the first side and the second side of the drill shaft such that a portion of the long sides are exposed beyond both the first side and the second side of the drill shaft.