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EP0219959A2
Expired / Lapsed
EP
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Rock bit with wear resistant inserts
Assignee: Smith International Inc
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Filing: 1986-09-05
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Granted: —
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Expires: 2006-09-05
Abstract
Abstract A rock bit has three cones with tunsgten carbide inserts in the cutting structure of each cone. The gage row inserts have a layer of polycrystalline diamond on the converging portion protruding from the surface of the cone. One or more transition layers are provided between the tungsten carbide insert body and the polycrystalline diamond layer. Such a transition layer comprises diamond and precemented tungsten carbide.
Inventors
- 👤 David Richard Hall
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 16:11
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/46; E21B10/56; E21B10/567; E21B10/573; E21B10/5735; B; B22; B22F; B22F7/00; B22F7/06; C; C22; C22C; C22C26/00; E21B10/50; E21B10/52; E21B10/5673; B22F2998/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
166 words
A rock bit comprising: a steel body; means at one end of the body for connecting the bit to a drill string; means at the opposite end of the body for mounting at least one roller cone on the body for rotation around an axis transverse to the axis of the bit; at least one roller cone so mounted on the body for rolling on the bottom of a bore hole being drilled; a plurality of inserts in such a cone for crushing rock at the bottom of such a bore hole, at least a portion of such inserts comprising: a cemented tungsten carbide body having a grip length embedded in the cone and a converging end portion protruding from the surface of the cone; a polycrystalline diamond layer on the converging end of the carbide body; and at least one transition layer between the polycrystalline diamond layer and the carbide body, the transition layer comprising a composite containing diamond crystals and precemented tungsten carbide particles.
Claim 2
Dependent Claim
166 words
A rock bit comprising: a steel body; means at one end of the body for connecting the bit to a drill string; means at the opposite end of the body for mounting at least one roller cone on the body for rotation around an axis transverse to the axis of the bit; at least one roller cone so mounted on the body for rolling on the bottom of a bore hole being drilled; a plurality of inserts in such a cone for crushing rock at the bottom of such a bore hole, at least a portion of such inserts comprising: a cemented tungsten carbide body having a grip length embedded in the cone and a converging end portion protruding from the surface of the cone; a polycrystalline diamond layer on the converging end of the carbide body; and at least one transition layer between the polycrystalline diamond layer and the carbide body, the transition layer comprising a composite containing diamond crystals and precemented tungsten carbide particles.
Claim 3
Dependent Claim
28 words
A rock bit as recited in Claim 1 characterised in that the transition layer comprises 40% by volume polycrystalline diamond and 60% by volume precemented tungsten carbide particles.
Claim 4
Dependent Claim
23 words
A rock bit as recited in Claim 2 characterised in that the polycrystalline diamond layer includes from 1 to 10% by volume cobalt.
Claim 5
Dependent Claim
32 words
A rock bit as recited in any one of Claims 1 to 3 characterised in that the polycrystalline diamond layer has a thickness in the range of from 75 to 600 microns.
Claim 6
Dependent Claim
26 words
A rock bit as recited in Claim 4 characterised in that the transition layer has a thickness in the range of from 100 to 600 microns.
Claim 7
Dependent Claim
32 words
A rock bit as recited in Claim 5 characterised in that the transition layer comprises from 5 to 95% by volume diamond and from 95 to 5% by volume precemented tungsten carbide.
Claim 8
Dependent Claim
57 words
A rock bit as recited in any one of the preceding characterised by Claims comprising a second transition layer between the first transition layer and the cemented tungsten carbide body, the second transition layer comprising a composite containing a lower proportion of diamond crystals and a higher proportion of precemented tungsten carbide than the first transition layer.
Claim 9
Dependent Claim
61 words
A rock bit as recited in any one of Claims 1 to 6 characterised in that the transition layer has a gradual transition between a relatively higher diamond content and relatively lower precemented tungsten carbide content adjacent to the polycrystalline diamond layer, and a relatively lower diamond content and relatively higher precemented tungsten carbide content adjacent to the tungsten carbide body.
Claim 10
Dependent Claim
27 words
A rock bit as recited in any one of the Claims preceding characterised in that the inserts are in a gage row of inserts in such cone.
Claim 11
Dependent Claim
29 words
A rock bit as recited in Claim 9 characterised in that the inserts inwardly from the gage row inserts comprise cemented tungsten carbide without a layer of polycrystalline diamond.
Claim 12
Dependent Claim
43 words
A rock bit as recited in any one of the preceding Claims characterised in that such an insert has a converging end portion selected from the group consisting of a projectile shape, a cone with a rounded end, a chisel shape, and hemispherical.
Claim 13
Dependent Claim
50 words
A rock bit as recited in any one of the preceding Claims characterised in that substantially the entire converging portion of such an insert has a polycrystalline diamond layer and a transition layer comprising diamond crystals and precemented tungsten carbide between the diamond layer and the cemented tungsten carbide body.
References Cited (Backward Citations)
No citation records indexed.
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