Ultra hard insert cutters for heel row rotary cone rock bit applications
AssigneeSmith International, Inc.
InventorsChris E. Cawthorne, Scott D. McDonough, Gary Portwood, Michael A. Siracki
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Abstract
A rotary cone rock bit for drilling boreholes in an earthen formation is disclosed. One or more rotary cones are rotatively retained on a journal bearing connected to the rock bit. These rotary cones form a circumferential heel row with extended ultra hard shaped cutters spaced within the heel row. Each of the shaped cutters form a cutting surface that extends above the heel row or is angled with respect to the formation to maintain the cutters in compression while the cutters shear a borehole wall. The shaped cutters serve to maintain the borehole diameter.
Claims24
A rotary cone rock bit for drilling in an earthen formation comprises one or more rotary cones rotatively retained on a bearing connected to a body of said rock bit, each cone forms a circumferential heel row with diamond inserts spaced within said heel row, each of said diamond inserts forms a first exposed polycrystalline diamond surface that is about adjacent to said formation, said diamond insert is a right angle cylindrical body, an edge formed by said cylinder at said exposed diamond surface is chamfered, an edge formed by said chamfer nearest said exposed polycrystalline diamond surface of said insert is radiused to reduce cracking and chipping of the diamond, said inserts serve to maintain a constant diameter borehole wall formed by said formation as said rotary cone rotates against a bottom of said borehole.
A rotary cone rock bit for drilling boreholes in earthen formation comprises one or more rotary cones rotatively retained on a bearing connected to a body of said rock bit, each cone forming a circumferential heel row, with extended inserts spaced within said heel row, each of said inserts forms a first diamond cutting surface that is angled with respect to the formation to maintain the inserts in compression, a leading edge formed by said diamond surface of said insert being further away from the formation than a trailing edge formed by the diamond surface of said insert, the diamond heel row inserts with their angled cutting surface serve to maintain a substantially constant borehole diameter as the rotary cone rotates against a bottom of said borehole.
A rotary cone rock bit for drilling boreholes in an earthen formation comprises one or more rotary cones rotatively retained on a bearing connected to a body of said rock bit, each cone forming a circumferential heel row with two or more rows of heel inserts on different radial distances from a cone axis, at least one row contains diamond faced inserts, said diamond faced inserts being on a shorter radial distance than another heel row containing inserts formed from tougher ultra hard material.
Dependencies are inferred from the claim text.