| 摘要 |
A diamond cutting tooth for use in a petroleum drag bit is provided with an extended and expanded effective diamond cutting surface by providing a linear sequence of triangular prismatic, synthetic, polycrystalline, diamond cutting elements generally along the line of direction of cutting within each tooth. Each element is offset from the preceding element in the sequence in a direction nonparallel to the line of cutting. More particularly, equilateral triangular prismatic diamond elements are laid within a V-shaped groove within a mold from which the cutting tooth is molded through conventional infiltration matrix techniques. The apical opening of the groove is 70 degrees, whereas the apical extent of each of the triangular apexes is 60 degrees. Each triangular element is laid on one side or other of the longitudinal groove. Matrix metal or binder is filled in the groove between the diamond elements thus forming a diamond cutting tooth having an effective apical dihedral angle of 70 degrees while using only 60-degree triangular prismatic elements. Worn triangular prismatic elements can be particularly adapted to this tooth structure by orienting at least one worn portion of each triangular element oriented toward the interior of the tooth with the remaining unworn point or points disposed nearest the exterior of the cutting tooth.
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