Earth boring tool with improved arrangement of cutter side rakes

摘要

Earth boring tools with a plurality of fixed cutters have side rake or lateral rakes configured for improving chip removal and evacuation, drilling efficiency, and/or depth of cut management as compared with conventional arrangements.

主权项

1. A rotary apparatus for boring earth, comprising:
a body having a central axis about which the apparatus is intended to rotate, and at least one blade; and at least two pairs of primary cutters on the blade, the cutters in each said pair being mounted in adjacent, fixed positions on the blade, the cutters partially defining at least a portion of a cutting profile for the apparatus when the apparatus is rotated, each of the cutters having a fixed, generally flat cutting face, a predetermined radial position within the cutting profile based on its distance from the central axis, and a predetermined orientation for its cutting face, the predetermined orientation comprising a side inclination angle, which angle can have a polarity that is negative, zero, or positive, wherein one of the cutters in each of the pairs of cutters has a side inclination angle with one of said polarities, and the other of the cutters in the each of the pairs of cutters has a side inclination angle with a different one of said polarities, and wherein the cutting faces of the cutters in each of the pairs of cutters generally face toward each other.