Specific features of drilling mode with extendable working elements

The work is devoted to the calculation of main technological parameters a bit new patented design, essence which replace worn out working elements (carbide cutters or diamond-containing matrices) during drilling with new, not blunt tool right at bottom well. need correct method associated design feature crown, consists in fact that when using it, an annular larger width formed compared serial crowns same outer diameter. Therefore, known formulas for carbide and diamond have been supplemented appropriate correction values so ROPs bits are full development. So, as rock-cutting elements, factor introduced increases number crown sectors first second stages. In cutting, it necessary increase maximum speed tool, taking into account mining technical conditions penetration. Refined calculating mode allow preserving advantages extendable increasing by 1.7-1.8 times existing bits.