US3917009A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removable stem for raise bits
Assignee: Tamrock Canada Inc
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Filing: 1974-09-16
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Granted: 1975-11-04
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Expires: 1994-09-16
Abstract
Abstract A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating the earth formations surrounding the pilot hole includes a removable drive stem. The removable drive stem allows the raise bit to be transported through small drifts and helps extend the useful lifetime of the raise bit. The raise bit may be assembled without weakening the highly-stressed, heattreated drive stem by welding. The raise bit body includes a multiplicity of rolling cutters for contacting and disintegrating the earth formations surrounding the pilot hole. The raise bit body includes a fixed collar with a truncated conical inside surface. A two-piece, split, removable collar with an inside surface that matches the outside surface of the drive stem and a conical outer surface that matches the inside surface of the fixed collar is positioned around the drive stem. A flange at the end of the drive stem allows the split collar to be drawn up into the fixed collar thereby developing frictional forces between the mating surfaces of the fixed collar, the split collar, and the drive stem. A preload is induced into the system to insure proper torque transmittal at low bit loads.
Inventors
- 👤 Norman Dean Dyer
- 👤 Howard Earl Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:38
CPC Classifications
F; F16; F16D; F16D1/00; F16D1/06; F16D1/08; F16D1/09; F16D1/093; F16D1/094; E; E21; E21B; E21B10/00; E21B10/26; E21B10/28; E21B17/00; E21B17/02; E21B17/04; E21B7/00; E21B7/28; Y; Y10; Y10T; Y10T403/00; Y10T403/70; Y10T403/7047; Y10T403/7051; Y10T403/7052; Y10T403/7058
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
146 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole; a main bit body including a multiplicity of cutters for contacting and disintegrating earth formations surrounding the pilot hole; a central opening in said main bit body substantially surrounding said drive stem, said central opening having a conical inner surface that tapers inward toward said drive stem in the direction of said upper end of said drive stem; and means around said drive stem having a tapered outer surface that tapers inward toward said drive stem in the direction of said upper end of said drive stem and engages said conical inner surface for retaining said drive stem in said central opening and connecting said drive stem to said main bit body.
Claim 2
Dependent Claim
146 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole; a main bit body including a multiplicity of cutters for contacting and disintegrating earth formations surrounding the pilot hole; a central opening in said main bit body substantially surrounding said drive stem, said central opening having a conical inner surface that tapers inward toward said drive stem in the direction of said upper end of said drive stem; and means around said drive stem having a tapered outer surface that tapers inward toward said drive stem in the direction of said upper end of said drive stem and engages said conical inner surface for retaining said drive stem in said central opening and connecting said drive stem to said main bit body.
Claim 3
Dependent Claim
21 words
The bit of claim 1 including a flange projecting from said drive stem for contacting said means around said drive stem.
Claim 4
Dependent Claim
43 words
The bit of claim 2 wherein said drive stem has a lower end, said bit including a cap that fits over said lower end of said drive stem and bolt means for forcing said cap against said lower end of said drive stem.
Claim 5
Dependent Claim
139 words
A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a cutter stage body, said cutter stage body having an upper portion and a lower portion; a multiplicity of saddles mounted on said upper portion of said cutter stage body; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage body, said central opening having a conical inner surface tapering toward said upper portion of said cutter stage body; a drive stem positioned in said central opening; retaining element means around said drive stem for retaining said drive stem in said central opening, said retaining element means having an outer surface adapted to mate with said conical inner surface; and means for urging said retaining element means into said central opening.
Claim 6
Dependent Claim
139 words
A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a cutter stage body, said cutter stage body having an upper portion and a lower portion; a multiplicity of saddles mounted on said upper portion of said cutter stage body; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage body, said central opening having a conical inner surface tapering toward said upper portion of said cutter stage body; a drive stem positioned in said central opening; retaining element means around said drive stem for retaining said drive stem in said central opening, said retaining element means having an outer surface adapted to mate with said conical inner surface; and means for urging said retaining element means into said central opening.
Claim 7
Dependent Claim
30 words
The raise bit of claim 4 wherein said retaining element means is a two-piece collar with a conical outer surface tapering toward said upper portion of said cutter stage body.
Claim 8
Dependent Claim
141 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole; a main bit body including a multiplicity of cutters for contacting and disintegrating earth formations surrounDing the pilot hole; a collar positioned around said drive stem connected to said main bit body, said collar having a conical inner surface that tapers inward toward said drive stem in the direction of said upper end; a retaining element having a conical outer surface that matches said conical inner surface adapted to be positioned around said drive stem; a flange on the end of said drive stem for urging said retaining element into said collar; and cap means for contacting said flange and urging said retaining element into said collar.
Claim 9
Dependent Claim
141 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole; a main bit body including a multiplicity of cutters for contacting and disintegrating earth formations surrounDing the pilot hole; a collar positioned around said drive stem connected to said main bit body, said collar having a conical inner surface that tapers inward toward said drive stem in the direction of said upper end; a retaining element having a conical outer surface that matches said conical inner surface adapted to be positioned around said drive stem; a flange on the end of said drive stem for urging said retaining element into said collar; and cap means for contacting said flange and urging said retaining element into said collar.
Claim 10
Dependent Claim
131 words
A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole and a lower end; a cutter stage body; a multiplicity of saddles mounted on said cutter stage body; a multiplicity of rolling cutters positioned in said saddles; a collar positioned around the lower end of said drive stem and connected to said cutter stage body, said collar having an inner conical surface that tapers inward toward said drive stem in the direction of said upper end; and a retaining element means positioned between said collar and said drive stem, said retaining element means having a tapered outer surface adapted to mate with said conical inner surface.
Claim 11
Dependent Claim
131 words
A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: a drive stem having an upper end for projecting into said pilot hole and a lower end; a cutter stage body; a multiplicity of saddles mounted on said cutter stage body; a multiplicity of rolling cutters positioned in said saddles; a collar positioned around the lower end of said drive stem and connected to said cutter stage body, said collar having an inner conical surface that tapers inward toward said drive stem in the direction of said upper end; and a retaining element means positioned between said collar and said drive stem, said retaining element means having a tapered outer surface adapted to mate with said conical inner surface.
Claim 12
Dependent Claim
34 words
The raise bit of claim 7 including a flange projecting from said drive stem and a cap means positioned over said flange for urging said tapered surface into contact with said conical inner surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |