ROLLER REAMER Russian patent published in 2008 - IPC E21B10/30 E21B7/28 

FIELD: drilling equipment, particularly longitudinal axis roller reamers adapted to retain well diameter during rock-cutting device operation.

SUBSTANCE: roller reamer comprises hollow body with eccentric areas carrying roller cutters with rock-cutting bits. The roller cutters are connected to eccentric areas by means of eccentric bushes so that the roller cutters are shifted one from another in plane view. The bushes are secured to body by means of pins. All roller cutters have walls with the same thickness in any wall section. Inner bush surface of outer body surface touching the inner bush surface has additional longitudinal grooves for pin receiving. Angle between extreme slots is defined as α=360·δ/(E_b+E_c), where δ is admissible roller cutter structure wear, E_b and E_c are bush and body eccentricities. One of extreme pin-receiving grooves made in touching body or bush surfaces is made in maximal eccentricity plane.

EFFECT: extended service life and increased operational reliability.

2 cl, 2 dwg