INSERTED ROLLER BIT Russian patent published in 2001 - IPC

FIELD: rock cutting tools for well drilling, particularly, inserted bits. SUBSTANCE: inserted roller bit consists of roller bit set and bit turning mechanism. Inserted tool including inserted roller bit, downhole motor with loading device and head for overshot is transported to bottom hole and retrieved to surface inside drill pipe string upon completion of drilling. Bottom-hole assembly in drill string is equipped with mounting seat and bushing of radial bearing of inserted bit. Inserted roller bit has internal spindle with water courses, projection in middle part an shoe in lower part with leg installed on it with roller bit, external circular holder to which leg with roller bit is hinged or external circular holders to which legs with roller bits are hinged. Rigidly connected to leg is flushing branch pipe whose external surface is made in form of polyhedron engageable with corresponding surfaces of leg or legs. Holder is hinged to sleeve by means of grooves in which circular sectors are installed and locked from inside with insert fixed by spindle. Sleeve is connected with spindle by splines. Sleeve has recess forming slide valve together with spindle projection. Circular piston together with slide valve forms piston hydraulic mechanism for changing drill bit from transportation to working position. Installed below piston mechanism in spindle channel is pipe union. EFFECT: higher solidity of detachable legs of roller bit set of inserted bit and their joint with shoe of turning mechanism, eliminated adverse effect of moment load onto holder members of turning mechanism. 2 cl, 11 dwg