
US Patent No: 5,244,039
Number of patents in Portfolio can not be more than 2000
Rotary drill bits
Stats
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Sep 14, 1993
Issued date -
Oct 31, 1991
filing date -
07/786,035
serial no -
In Force
status
Importance
Abstract
A rotary drill bit for drilling holes in subsurface formations comprises a bit body having a shank for connection to a drill string, a plurality of preform primary cutting elements mounted on the bit body and defining a primary cutting profile having a downwardly convex nose portion. There are associated with at least certain of the primary cutting elements respective secondary elements which are spaced inwardly of the primary profile. The distance of the secondary elements from the primary profile, when measured in a direction perpendicular to said profile, is generally greater for secondary elements nearer the nose portion than it is for secondary elements further away from the nose portion, and is preferably such that the vertical distance of the secondary elements from the profile is substantially constant.
First Claim
Related Publications
International Classification(s)
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- [Patents Count]
Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
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| 4,429,755 Drill with polycrystalline diamond drill blanks for soft, medium-hard and hard formations | 30 | 1981 | |
| 4,475,606 Drag bit | 29 | 1982 | |
| 4,545,441 Drill bits with polycrystalline diamond cutting elements mounted on serrated supports pressed in drill head | 46 | 1984 | |
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| 4,889,017 Rotary drill bit for use in drilling holes in subsurface earth formations | 149 | 1988 | |
| 4,942,933 Relating to rotary drill bits | 22 | 1988 | |
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| 4,718,505 Rotary drill bits | 47 | 1985 | |
| 4,823,892 Rotary drill bits | 26 | 1987 | |