Patent US3885838A successfully refreshed from Google Patents.
US3885838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drill bit bearings
Assignee: Camco Drilling Group Ltd
•
Filing: 1973-06-14
•
Granted: 1975-05-27
•
Expires: 1993-06-14
Abstract
Abstract A roller drill bit of the type in which a rotatable cutter is supported against radial and thrust loading on a shaft in which thrust and other frictionally engaging bearing surfaces between the cutter and the shaft are established by uncarburized surface portions in either the cutter of the shaft which are otherwise formed of carburized or case hardened steel thereby avoiding heat cracks and spalling of the steel between the bearing surfaces.
Inventors
- 👤 John S Childers
- 👤 Clayton C Mandrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:11
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/08; E21B10/22; F; F16; F16C; F16C21/00; F16C2352/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
154 words
A drill bit including: a bearing shaft having an inboard end, a rotatable cutter of carburizing steel mounted on the inboard end of said shaft, at least the exterior surface of said cutter and portions of the interior surfaces thereof being carburized, the shaft having a ball raceway, the cutter having a ball raceway registering with the ball raceway in said shaft, ball bearings in said raceways serving to rotatably lock the cutter on said shaft, the said shaft having a radially outwardly extending annular bearing surface inboard of said ball raceway, the interior of the cutter having a radially inwardly extending annular bearing surface registering with and adapted to engage the radial bearing surface on said shaft to carry outboard thrust loads imposed on the cutter, at least the radial cutter bearing surface being uniformly uncarburized throughout at least a substantial portion thereof to alleviate frictional heat cracking thereof during the drilling operation.
Claim 2
Dependent Claim
154 words
A drill bit including: a bearing shaft having an inboard end, a rotatable cutter of carburizing steel mounted on the inboard end of said shaft, at least the exterior surface of said cutter and portions of the interior surfaces thereof being carburized, the shaft having a ball raceway, the cutter having a ball raceway registering with the ball raceway in said shaft, ball bearings in said raceways serving to rotatably lock the cutter on said shaft, the said shaft having a radially outwardly extending annular bearing surface inboard of said ball raceway, the interior of the cutter having a radially inwardly extending annular bearing surface registering with and adapted to engage the radial bearing surface on said shaft to carry outboard thrust loads imposed on the cutter, at least the radial cutter bearing surface being uniformly uncarburized throughout at least a substantial portion thereof to alleviate frictional heat cracking thereof during the drilling operation.
Claim 3
Dependent Claim
20 words
A drill bit according to claim 1 wherein means are provided to circulate fluid into the interior of said cutter.
Claim 4
Dependent Claim
45 words
A drill bit according to claim 1 wherein the inner end of the bearing shaft has a cylindrical pilot pin and the cutter has a cylindrical portion in bearing engagement with said pilot pin, the cylindrical bearing portion of said cutter also being substantially uncarburized.
Claim 5
Dependent Claim
23 words
A drill bit according to claim 1 wherein said bearing shaft and cutter include roller bearing raceways and roller bearings in said raceways.
Claim 6
Dependent Claim
21 words
A drill bit according to claim 1 wherein the radially extending shaft bearing surface has an inlay of suitable bearing material.
Claim 7
Dependent Claim
19 words
A drill bit according to claim 1 wherein seal means are provided between the cutter and the bearing shaft.
Claim 8
Dependent Claim
50 words
A drill bit according to claim 1 wherein said shaft is downwardly and inwardly inclined toward the inboard end thereof, the outwardly and downwardly facing side of said shaft establishing an outboard surface thereon and wherein an appreciable portion of the outboard surface of the shaft ball race is uncarburized.
Claim 9
Dependent Claim
95 words
A drill bit bearing including: a bearing shaft of carburizing steel extending downwardly and inwardly toward the rotational axis of a rotary head carrying said bearing shaft, a roller cutter also of carburizing steel on said shaft, the shaft and cutter each having a friction bearing surface arranged to carry outboard thrust loads imposed on the cutter, the surfaces of said shaft and said cutter being carburized except at least one of said friction bearing surfaces being uniformly uncarburized throughout at least a substantial porTion thereof to alleviate frictional heat cracking thereof during drilling operation.
Claim 10
Dependent Claim
95 words
A drill bit bearing including: a bearing shaft of carburizing steel extending downwardly and inwardly toward the rotational axis of a rotary head carrying said bearing shaft, a roller cutter also of carburizing steel on said shaft, the shaft and cutter each having a friction bearing surface arranged to carry outboard thrust loads imposed on the cutter, the surfaces of said shaft and said cutter being carburized except at least one of said friction bearing surfaces being uniformly uncarburized throughout at least a substantial porTion thereof to alleviate frictional heat cracking thereof during drilling operation.
Claim 11
Dependent Claim
21 words
A drill bit bearing according to claim 8 wherein means are provided to circulate fluid into the interior of said cutter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |