Hole opener and method for drilling

摘要

The present document describes a drill-bit which achieves both the rigidity and a fast rate of penetration. The drill-bit comprises a cone shaped central portion comprising a plurality of ribs protruding from the central portion and defining a plurality of blades. The blades are curved along a direction of a longitudinal axis of the cone to facilitate insertion into a hole when rotating in a first direction, and exit from the hole when rotating in a second direction opposite the first direction. The drill-bit comprises a plurality of polycrystalline diamond cutters (PDC) on the blades provided in a first position for cutting the hard structure as the drilling-bit rotates in the first direction, and a plurality of up-drill PDC cutters provided in a second position for cleaning the hole as the drill-bit rotate in the second direction to exit the hole.

主权项

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.