BLADE DRILL BIT Russian patent published in 2006 - IPC E21B10/42 

FIELD: mining, particularly to create blade drilling bits adapted to perform full face drilling of hydrogeological, drainage and other wells and to produce worm augers.

SUBSTANCE: drill bit comprises body, head coaxial with the body, blades with replaceable rock-cutting cutters secured to holders and formed as hard-alloy plates with positive front angles. Head is provided with replaceable rotary and pilot cutters. Front cutter angle magnitudes decrease as distance between cutter and drill bit axis changes. Front angle α of peripheral cutter has maximal magnitude defined by physical and mechanical rock properties. As cutter approaches drill bit axis magnitude of front angle thereof decreases for value proportionate to reduction of radius of particular cutter installation relatively peripheral cutter. The valued is determined from β=α·R_i/R_p, where α and β are magnitudes of front angles of peripheral and particular cutters, R_i and R_p are radii of peripheral and particular cutters installation.

EFFECT: increased uniformity of drill bit wear and provision of trouble-free operation.

2 dwg