Patent US4249781A successfully refreshed from Google Patents.
US4249781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary drilling bit with conically shaped rotary cutters
Assignee: SKF GmbH
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Filing: 1978-12-05
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Granted: 1981-02-10
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Expires: 1998-12-05
Abstract
Abstract A rotary drilling bit with conically shaped rotary cutters which are supported in bearings on the drilling bit body by a plurality of bearings. At least one seal is provided in each rotary cutter for separating the bearing cavities of the bearings.
Inventors
- 👤 Armin Olschewski
- 👤 Heinrich Kunkel
- 👤 Manfred Brandenstein
- 👤 Lothar Walter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:07
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/08; E21B10/22; E21B10/25; F; F16; F16C; F16C21/00; F16C2352/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
150 words
A rotary drill bit comprising a drill bit for minimizing lubricant leakage losses and for withstanding high operating temperatures body and at least one rotary cutter rotatably supported on the drill bit body by a plurality of load carrying bearing assemblies in a cavity between the rotary cutter and drill bit body, at least two seal member means in said cavity, one seal member means sealing said cavity from the outside environment and said other seal member means dividing said cavity into at least two discrete, enclosed chambers for preventing lubricant at the tip of the rotary cutter from being carried by centrifugal force toward the end of the rotary cutter facing the drill bit body, a load carrying bearing assembly in each chamber and a a different non-circulating lubricant in each of said separate chambers, said lubricants being suited for different running temperatures of the bearings in each chamber.
Claim 2
Dependent Claim
150 words
A rotary drill bit comprising a drill bit for minimizing lubricant leakage losses and for withstanding high operating temperatures body and at least one rotary cutter rotatably supported on the drill bit body by a plurality of load carrying bearing assemblies in a cavity between the rotary cutter and drill bit body, at least two seal member means in said cavity, one seal member means sealing said cavity from the outside environment and said other seal member means dividing said cavity into at least two discrete, enclosed chambers for preventing lubricant at the tip of the rotary cutter from being carried by centrifugal force toward the end of the rotary cutter facing the drill bit body, a load carrying bearing assembly in each chamber and a a different non-circulating lubricant in each of said separate chambers, said lubricants being suited for different running temperatures of the bearings in each chamber.
Claim 3
Dependent Claim
44 words
A rotary drill bit as claimed in claim 1 wherein said bearing assemblies comprise at least one roller bearing and at least one friction bearing and wherein said other seal member means is disposed between said bearings and defines separate cavities for each bearing.
Claim 4
Dependent Claim
28 words
A rotary drilling bit as claimed in claim 1 wherein said other seal member means is arranged slidably on the drilling bit body and in the rotary cutter.
Claim 5
Dependent Claim
27 words
A rotary drill bit as claimed in claim 1 wherein said other seal member means is axially fixed in an annular groove of the drill bit body.
Claim 6
Dependent Claim
27 words
A rotary drill bit as claimed in claim 1 wherein said other seal member means is radially fixed in an annular groove in the drill bit body.
Claim 7
Dependent Claim
28 words
A rotary drill bit as claimed in claim 1 including an edge ring at one end of said rotary cutter remote from the tip of the rotary 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) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |