DRILLING TOOL WITH COLLAPSIBLE REAMER BIT Russian patent published in 2003 - IPC

FIELD: drilling tools designed for drilling geological prospecting holes with retrievable core receivers without hoisting of drill pipes. SUBSTANCE: drilling tool with collapsible reamer bit has external and internal bodies with cuts passing into cuts of flexible plates provided with rock cutting sectors. External body has windows located in its middle part, and upper and lower recesses. Internal body has flexible plates different in length. Plates with smaller length have cuts and provided with reamer sections located in windows of external body. Long plates located between short plates have crown sectors and orienting plates for lower and upper recesses of external body. Invention provides for reduction of time taken for performance of auxiliary operations involved in process of hole drilling with improvement of well bore conditions and decrease of negative phenomena in round trip operations occurring in emergency situations and possible traumatism. EFFECT: higher efficiency of drilling operations. 10 cl