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

FIELD: mining.

SUBSTANCE: invention concerns rock destruction tool, and namely small-diametre rolling drilling bits. Rolling drilling bit includes legs with trunnions on which there installed are cutters mounted by means of radial thrust bearings one of which is locking bearing. The peculiar feature of the bit is that the second radial thrust bearing adjacent to locking bearing and located relative to it from the side of the bit axis is also locking-type; at that, races of locking bearings are interconnected with the channel attaching the upper part of the main locking bearing to the lower part of additional locking bearing. As working bodies in locking bearings there used are balls and annular segments having in cross section the shape of semi-circle; at that, working elements in the form of balls are located in upper part of the main locking bearing and in lower part - of the additional bearing; at that, length of arc of race for balls in additional locking bearing is not less than length of arc of loaded support part.

EFFECT: increasing operational life of bit bearing, and as a result, increasing operating efficiency of the whole bit.

4 cl, 3 dwg