BOX-TYPE ROLLING DRILLING BIT Russian patent published in 2011 - IPC E21B10/20 

FIELD: oil and gas production.

SUBSTANCE: box-type rolling drilling bit comprises a centre box with side hollows each of which has guide pins at the bottom for mounting and fastening of support brackets with movable rolling cutters mounted on journals. Each support bracket is supplied with a threaded through holes formed between a pair of holes for guide pins in a plane passing through their axes, and an expander element in the form of a threaded cap rod screwed in the threaded through holes. One end of the threaded rod rests against the box when screwed in the threaded through hole, and expands a section until mounted in a zero-tolerance position with respect to a bit diameter before tacking and box welding. Similarly, the two other sections are expanded when inverse cones of the rolling cutters rest against an internal surface of a rigid diametral ring gauge coaxial to the box.

EFFECT: higher accuracy, reliability and period of service of the box-type bits.

6 dwg