Patent ID: 9624732
Date: 2017-04-18
CPC Classifications: E21B

Claim:
1. A drill-bit for drilling a hole in a hard structure, the drill-bit comprising: a central portion having a first end, a second end, and a longitudinal axis; a plurality of blades protruding substantially radially from the central portion, each blade having: a first blade end, a second blade end, a first end portion, a second end portion and a middle portion; the first blade end is positioned closer to the first end than to the second end, and the second blade end is positioned closer to the second end than to the first end; the first end portion includes the first blade end and extends from the first blade end to the middle portion, and the first end portion includes an outer facing surface that extends from the first blade end to the middle portion, and at least a portion of the outer facing surface extends radially from the central portion perpendicular to the longitudinal axis; the middle portion is disposed between and connected to the first end portion and to the second end portion, the middle portion includes an outer facing surface that is parallel to the longitudinal axis, the outer facing surface of the middle portion forms a radially outermost diameter of the drill-bit; the second end portion includes the second blade end and extends from the middle portion toward the second end; a plurality of polycrystalline diamond cutters disposed on the outer facing surface of the first end portion, the plurality of polycrystalline diamond cutters extend the entire length of the outer facing surface of the first end portion from the first blade end to the middle portion.