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 comprises a front face having an outer surface portion, and an inner surface portion disposed radially inside of the outer surface portion. The inner surface portion is partially recessed by a cavity with respect to the outer surface portion. A plurality of fluid channels extends through the head portion and communicates with the cavity for conducting a flushing medium thereto. The inner surface portion comprises a raised portion carrying a plurality of buttons. An imaginary circle intersects centers of the fluid channels and also intersects an equal number of buttons.

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: A percussion drill bit for drilling a bore includes a drill body having a connecting section at a rear end thereof for connection to a percussive unit, and a plurality of cemented carbide buttons embedded in a front end of the drill body. Each button comprises a cemented carbide body having a rear mounting portion embedded in the drill body, and a front end protruding from the drill body. The front end of the cemented carbide button is substantially semi-spherically curved and defined by a radius whose origin is disposed axially rearwardly of a plane through the largest diameter of the button. The button projects from the drill bit body a distance which is not less than 50% of the button diameter. A conical intermediate surface forms, in cross-section, an acute angle of about 13–19° with an envelope surface of the rear mounting portion.