BLADE DRILL BIT Russian patent published in 2008 - IPC E21B10/42 

FIELD: mining.

SUBSTANCE: invention relates to rock destroying tool, in particular to blade drill bits. The blade drill bit incorporates a case, reinforced flat blades and fixing elements. The feature of the suggested blade drill bid is as follows: blind grooves of various lengths are made on the side surface of the case; folding flat blades are arranged in the said grooves. At that the blades are made removable and they are equipped with lengthwise through slots of various size and fixing elements installed at different levels against the end of the bit in its operating position. At the periphery of the case there are made lugs with horizontal holes wherein fixing elements are positioned; at that one of the lugs is located above the level of another at a value equal to the excess value of length of one slot over another.

EFFECT: facilitating entry of boreholes into soft rocks with simultaneous casing.

5 cl, 4 dwg