CROWN FOR IMPACT-ROTARY DRILLING Russian patent published in 2013 - IPC E21B10/46 

FIELD: mining.

SUBSTANCE: crown for impact-rotary drilling comprises a body with cleaning channels, which separate the end of the crown into sectors reinforced with well and core forming cutters. Reinforced well and core forming cutters are arranged in the front and rear part of the sector with central cutters of larger diametre with a high overhand and truncated top. At the same time at least some well and core forming cutters is made with a wedge-shaped working head, blades of which in each sector are aligned at the different angle to the crown radius. Cutters with wedge-shaped and semispherical working head in each sector are installed with alternation along with crown rotation. Tails of central cutters are installed with the positive angle of inclination - α, determined in accordance with the formula: α=β+(1-5)°, where β - angle of bevel of central cutters top.

EFFECT: increased efficiency of damage and considerable reduction of drilling works cost.

3 cl, 2 dwg