DRILLING BIT Russian patent published in 2007 - IPC E21B10/48 

FIELD: rock-cutting tools, particularly drilling bits provided with diamond cutting structure for well drilling along with core taking.

SUBSTANCE: drilling bit comprises body and matrix separated into sectors with flushing grooves. The sectors are provided with hole-forming, central and core-forming inserts made of superhard alloy and with protective members arranged in front of hole-forming and core-forming inserts. The protective members define polygons with two adjacent curvilinear surfaces in plan view. One curvilinear surface is aligned with outer surface of the insert, another one is in register with matrix side surface. If protective member is located in front of hole-forming insert it touches outer side surface of the matrix. If protective member is located in front of core-forming insert it contacts with inner matrix surface. Protective members are ahead of inserts with respect to heights thereof.

EFFECT: increased well drilling speed due to improved protection of inserts against vertical loads acted on drilling bit during bit lowering and due to prevention of tear-outs and ships during rock drilling.

2 cl, 6 dwg