Abstract: A rock drill bit for percussive drilling includes a front face which has radially outer and inner portions. Fluid channels are disposed in the head portion in communication with the inner portion of the front face. The inner portion of the front face carries a plurality of front buttons. The outer portion comprises circumferentially spaced steel portions which are axially raised relative to the inner portion. Each raised portion carries one or two peripheral buttons located radially outwardly of an imaginary circle which intersects at least two of the front buttons and at least two of the flushing channels. The imaginary circle is arranged coaxially relative to the center axis.

Abstract: The present invention relates to a rock drill bit for percussive drilling. The drill bit comprises a bit body, a head portion defining a longitudinal center axis. The head portion includes an axially forward rock-crushing surface and a skirt that extends axially rearwardly from the rock-crushing surface. The rock-crushing surface comprises several rock-crushing means. A circumferential outer surface of the skirt is provided with circumferentially spaced apart grooves forming lands therebetween. The grooves and the lands extend generally in an axial direction. An axially rearward portion of a land is provided with a guiding surface. The guiding surface faces radially outwardly. The guiding surface comprises at least one step or a sloping surface such to reduce the diametrical dimension stepwise or continuously, respectively. The guiding surface comprises a first guiding portion and a second guiding portion both situated radially outside of an imaginary extension line of the waist.

Abstract: The present invention relates to a rock drill bit for percussive drilling. The drill bit comprises a bit body, a head portion defining a longitudinal center axis. The head portion includes an axially forward rock-crushing surface and a skirt that extends axially rearwardly from the rock-crushing surface. The rock-crushing surface comprises several rock-crushing means. A circumferential outer surface of the skirt is provided with circumferentially spaced apart grooves forming lands therebetween. The grooves and the lands extend generally in an axial direction. An axially rearward portion of a land is provided with a guiding surface. The guiding surface faces radially outwardly. The guiding surface comprises at least one step or a sloping surface such to reduce the diametrical dimension stepwise or continuously, respectively. The guiding surface comprises a first guiding portion and a second guiding portion both situated radially outside of an imaginary extension line of the waist.

Abstract: A rock drill bit for percussive drilling includes a front face which has radially outer and inner portions. Fluid channels are disposed in the head portion in communication with the inner portion of the front face. The inner portion of the front face carries a plurality of front buttons. The outer portion comprises circumferentially spaced steel portions which are axially raised relative to the inner portion. Each raised portion carries one or two peripheral buttons located radially outwardly of an imaginary circle which intersects at least two of the front buttons and at least two of the flushing channels. The imaginary circle is arranged coaxially relative to the center axis.