DIAMOND CROWN BIT FOR CORE BARREL Russian patent published in 1997 - IPC

FIELD: methods and equipment for coring hard rocks. SUBSTANCE: diamond crown bit for core barrel has body with thread and diamond matrix separated into sectors by water courses. One water course width is larger than that of other water courses that provides eccentricity of matrix end. A part of sectors adjacent to the wide water course has diamond concentration exceeding that of the other sectors by 25%. Mathematical relations for calculation of matrix end eccentricity and central angle of the sector with increased diamond concentration are offered. EFFECT: higher efficiency. 5 dwg