(54) Title: HARD METAL INSERT FOR A DRILL BIT FOR PERCUSSION DRILLING AND METHOD FOR GRINDING A HARD METAL INSERT (57) Abstract: The present invention comprises a hard met¬al insert (1 ) intended to be comprised within a drill bit for percussion drilling, which insert comprises a cap (2), which constitutes a wear part comprising a wear surface (2a) and a cylindrical part (3), which, constitutes a mount with a cross-sectional area (A) and a diameter (D) The cap (2) comprises a front part (4) with an extension (H) along the axis of sym¬metry (x) of the insert from a first point (a) on the wear sur¬face (2a) of the cap to a second point (b) in the cap. The front part (4) constitutes a volume (Vf) between a first plane (I), which intersects at right angle to the axis of sym¬metry (x) at the first point (a), and a second plane (II), which intersects at right angle to the axis of symmetry (x) at the second point (b). The volume (VI) is greater than or equal to 0.6 times the cross-sectional a

摘要

pThe present invention comprises a hard metal insert (1 ) intended to be comprised within a drill bit for percussion drilling, which insert comprises a cap (2), which constitutes a wear part comprising a wear surface (2a) and a cylindrical part (3), which constitutes a mount with a cross-sectional area (A) and a diameter (D) The cap (2) comprises a front part (4) with an extension (H) along the axis of symmetry (x) of the insert from a first point (a) on the wear surface (2a) of the cap to a second point (b) in the cap. The front part (4) constitutes a volume (Vf) between a first plane (I), which intersects at right angle to the axis of symmetry (x) at the first point (a), and a second plane (II), which intersects at right angle to the axis of symmetry (x) at the second point (b). The volume (Vf) is greater than or equal to 0.6 times the cross-sectional area (Af) of the front part in the second plane times the distance (H) along the axis of symmetry (x) between the first point (a) and the second point (b), and the diameter (Df) of the front part in the second plane is greater than or equal to 0.5 times the diameter (D) of the mount and less than or equal to 0.6 times the diameter (D) of the mount. The invention also relates to a method for regrinding a worn insert./p [WO2011043717A1]