DEMOUNTABLE ROLLING DRILLING BIT WITH REPLACEABLE ROLLING CUTTERS AND VARYING AXES OF SUPPORT BRACKET SECTIONS Russian patent published in 2011 - IPC E21B10/20 

FIELD: oil and gas production.

SUBSTANCE: demountable rolling bit comprises: a nipple, a box (a faceplate), nuts, spring washers, locking plates, variable-section support bracket sections with a threaded shank for retention of the support bracket section in the box, split flanges, covers, spring washers, screws, rolling cutters, cylindrical rollers, split-shell bearings, measuring plates, split pins. Planes of box and nipple support are perpendicular to a bit axis. The support bracket sections are fastened to the box with the use of the locking plates, the spring washers with a pinned nut. The rectangular grooves in the box are increased towards an external edge of the bit case by an X value that enables displacing an support bracket section axis with respect to the bit axis by this value. The support bracket section is L-shaped, and an inclination of the support bracket axis to the bit axis varies with the rock properties. An end portion of the support bracket section (pin) is spherically-shaped for the slide bearing.

EFFECT: higher reliability and prolonged period of service of the bit structure.

6 dwg