RIG TO DRILL HOLES Russian patent published in 2001 - IPC

FIELD: drilling equipment. SUBSTANCE: invention specifically refers to equipment intended to drill deep holes of large diameter by planetary-drill bit method. Packer is located in upper part of face transmission of rig, on outer pipe of double drill pipe string. Its unclamping unit is mounted for prevention of axial movement of transmission relative to housing with the aid of spring. Face plate of housing of unclamping unit has windows for overflow of fluid. Unclamping unit is mounted for free rotation relative to outer pipe and can move axially along guiding rods put on face plate of housing of unclamping unit jointly with outer pipe. Valves whose number corresponds to number of windows for overflow of fluid in unclamping unit are installed to shut off these windows in case of axial movement of unclamping unit. EFFECT: increased reliability and serviceability of rig. 2 cl, 3 dwg