CORE DRILLING BIT Russian patent published in 1994 - IPC

FIELD: well drilling. SUBSTANCE: core drilling bit has additional core-forming members connected with body 1 and core catcher. Core catcher is made in form of collet flexible ring 8 with collar 9 of flexible material. Body 1 is made with inclined water courses 13 communicated with hollow of central water course 2 and hollow of slots 14. Body 1 has inclined water courses 15 of smaller diameter communicated with side water courses 3 and 4. In extreme upper position, flexible ring 8 is located above inclined water courses 13. Central water course 2 below courses 13 is uniformly narrowing downwards. EFFECT: higher efficiency. 5 dwg