ROLLING DRILLING BIT Russian patent published in 2010 - IPC E21B10/08 E21B10/22 

FIELD: mining.

SUBSTANCE: rolling drilling bit includes legs on the trunnions of which there installed are cutters mounted by means of the locking unit formed with annular groove near the trunnion bottom, screw groove combined with it on the trunnion and shoulder on the cutter edge, which is arranged in the operating position in annular groove of the trunnion. The specific feature of the proposed bit is its being equipped with additional locking ball bearing, and the design of the cutter, which includes widened running track for ball locking bearing located relative to screw track of the trunnion on the side of the bit axis. At that, end surface of annular groove and the side surface of the cutter shoulder, which contacts it, are inclined; at that, their inclination angle is equal. Minimum length of annular groove is more than the length of the cutter shoulder.

EFFECT: increasing operating efficiency of the bit owing to effective destruction of the strip at bottom hole and increasing the life time of its support.

3 cl, 2 dwg