PERCUSSIVE DRILL BIT WITH MULTIPLE SETS OF FRONT CUTTING INSERTS Russian patent published in 2018 - IPC E21B10/36 

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to a percussive drill bit for a rock and a percussive drill device comprising said bit. Percussive drill bit comprises a head provided at one end of an elongate shank. Head has a forward-facing front surface bounded by a peripheral edge. Percussive drill bit also comprises a plurality of end cutting inserts distributed on the front surface in various radial positions between the central axis extending through the drill bit and the peripheral edge of the front surface. First inner set of cutting inserts is arranged radially innermost on or towards the axis. Calibration inserts are arranged on or towards the peripheral edge. Additional end cutting inserts are grouped into multiple sets. Each set is arranged between the radially innermost set and the calibration group, comprises the same number of inserts and is placed at a different radial distance from the axis. Each insert of each respective set is placed at the same radial distance. Each insert of each set is placed circumferentially between a pair of inserts of an adjacent radially inner and / or radially outer set so that the positions of the inserts of adjacent sets are staggered around the circle. Angular separation between adjacent inserts in a set is the same for all inserts. Diameter of the inserts in at least one set is larger than the diameter of the inserts in the corresponding radially inner set and / or radially the innermost group of inserts.

EFFECT: technical result is higher penetration rate and longer bit life.

12 cl, 4 dwg