US5101692A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drill bit or corehead manufacturing process
Assignee: Brit Bit Ltd
•
Filing: 1990-09-14
•
Granted: 1992-04-07
•
Expires: 2010-09-14
Abstract
Abstract A two-part investment casting process is described which involves first casting a hard material shell (32) such as stellite, which is threaded or profiled internally to allow attachment to a pre-machined shank (44) such that the advantages of a fluid and wear resistant investment casting of complex shape may be combined with a tough and machinable shank to allow attachment to the drill string.
Inventors
- 👤 Neil A. A. Simpson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:23
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/46; E21B10/54; E21B10/55; B; B22; B22D; B22D19/00; B22D19/06; B23; B23P; B23P15/00; B23P15/28; B23P15/32; Y; Y10; Y10S; Y10S76/00; Y10S76/11; Y10S76/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
111 words
A method of fabricating a drill bit or coring bit, said method comprising the steps of: investment casting a relatively hard outer shell of said bit as an initially separate component of said bit, said shell being externally formed substantially to the finished external form of said bit; providing a pre-machined bit shank of a relatively less hard material as an initially separate component of said bit; said shell and one end of said shank being provided with respective mutually cooperable connecting means; said shank having another end thereof formed as a drill string connector; and mechanically connecting said shell with said bit by connecting the said mutually cooperable connecting means.
Claim 2
Independent Claim
111 words
A method of fabricating a drill bit or coring bit, said method comprising the steps of: investment casting a relatively hard outer shell of said bit as an initially separate component of said bit, said shell being externally formed substantially to the finished external form of said bit; providing a pre-machined bit shank of a relatively less hard material as an initially separate component of said bit; said shell and one end of said shank being provided with respective mutually cooperable connecting means; said shank having another end thereof formed as a drill string connector; and mechanically connecting said shell with said bit by connecting the said mutually cooperable connecting means.
Claim 3
Dependent Claim
21 words
A method as claimed in claim 1, said method comprising the further step of subsequently locking said mutually cooperable connecting means.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 2, wherein said mutually cooperable connecting means are locked by a mechanical lock.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 2, wherein said mutually cooperable connecting means are locked by fusion bonding of respective mating surfaces of said cooperable connecting means.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 2, wherein said mutually cooperable connecting means are locked by fusion bonding of mutually adjacent portions of said shell and said shank.
Claim 7
Dependent Claim
37 words
A method as claimed in claim 1, wherein said mutually cooperable connecting means comprises a female screw thread formed internally in said shell and a cooperable male screw thread formed in said one end of said shank.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 1, wherein said relatively hard material of which said outer shell is resistant to abrasive wear and resistant to fluid erosion.
Claim 9
Dependent Claim
18 words
A method as claimed in claim 7, wherein said relatively hard material is a high content cobalt alloy.
Claim 10
Dependent Claim
15 words
A method as claimed in claim 8, wherein said high content cobalt alloy is stellite.
Claim 11
Dependent Claim
32 words
A method as claimed in claim 1, wherein said relatively less hard material of which said pre-machined bit shank is relatively easily machinable and has the capability of withstanding high stress/fatigue levels.
Claim 12
Dependent Claim
15 words
A method as claimed in claim 10, wherein said relatively less hard material is steel.
Claim 13
Dependent Claim
15 words
A drill bit or coring bit fabricated by the method as claimed in claim 1.
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) | 1995-04-07 | 1995-10-07 | 1996-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-07 | 1999-10-07 | 2000-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-07 | 2003-10-07 | 2004-04-07 | $7700.00 | Window Closed / Lapsed |