DRILLING TOOL Russian patent published in 1997 - IPC

FIELD: well drilling with continuous lifting of core. SUBSTANCE: drilling tool has rock cutting tool with water courses and connected outer barrel string with radial channel and packer located under it, inner barrel string with ribs, which separate interbarrel space into two isolated chambers. Inner barrel string components have retainers from turning and those of outer barrel string have safety locks. The latter are located on both sides of radial channel for engagement with ribs of inner barrel string. Retainers may be made in form of cam pair, and safety locks are made in form of pins or screws. EFFECT: higher efficiency. 3 cl, 3 dwg