CUTTING TOOTH AND A ROTATING BIT HAVING A FULLY EXPOSED POLYCRYSTALLINE DIAMOND ELEMENT

摘要

The present invention is an improvement in the cutting tooth used in a rotating drilling bit wherein the cutting tooth incorporates a synthetic triangularly shaped prismatic diamond element. The polycrystalline diamond element is substantially exposed above the bit face of the bit and is supported and retained on the bit face by disposition within a tooth of matrix material integrally formed with the bit face. The tooth is particularly characterized by having a trailing support in the shape of a tapered teardrop with a leading face on the trailing support that is at least in part adjacent and contiguous to the trailing face of the diamond cutting element and is congruous at the plane of contact with the diamond cutting element and tapers thereafter to a point on the bit face to minimize the amount of matrix material in the tooth which must to be removed by wearing before a useful cutting surface of the polycrystalline diamond element can be exposed.