ECCENTRIC REAMER Russian patent published in 2000 - IPC

FIELD: drilling operations. SUBSTANCE: given eccentric reamer is designed to form hole larger than diameter of casing string or of drilled shaft through which tools are sunk to face. Reamer has body, reaming members falling outside of dimensions of drill bit. Specific feature of proposed reamer lies in displacement of axis of upper joining thread of body relative to its axis so that condition of equality of moments of loads emerging on drill bit and reamer with regard to axis of displacement of joining thread is fulfilled. EFFECT: prevention of deviation of drill bit from center and provision for drilling of hole of design diameter. 3 dwg