| 摘要 |
<p>A drill bit for connection to a drill string has a bit body (2) with a cutting face (7), which supports a plurality of cutting elements (18). The cutting elements (18) comprise a cylindrical supporting stud (19) of sintered carbide which has a diamond cutting element (26) mounted thereon. The diamond cutting elements (26) have a novel cutting shape facilitating drilling through hard formations with a minimum of applied weight on the bit. The cutting elements (26) are in the shape of a relatively large disc shaped cutter commonly used for medium and soft formations but have the sides shaped into a cutting edge (126) of substantially smaller radius. The cutting element (26) has the strength and resistance to breakdown of the larger disc but the cutting capacity in hard formations of a smaller diameter cutter. The cutting elements (26) are also disclosed as novel components of the drill.</p> |
