US3920089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removable stem for raise bit
Assignee: Tamrock Canada Inc
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Filing: 1974-03-07
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Granted: 1975-11-18
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Expires: 1994-03-07
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 removability of the drive stem allows the raise bit to be transported through small drifts and extends the useful lifetime of the raise bit. The raise bit body includes a multiplicity of rolling cutters for contacting and disintegrating the earth formations surrounding the pilot hole. A central opening extends through said raise bit body. One end of the drive stem extends into the central opening. A pair of flats is located near the end of the drive stem. A retaining element is positioned in the flats and is bolted to the raise bit body.
Inventors
- 👤 Howard Earl Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:33
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/28; E21B10/00; E21B10/26; E21B10/265; E21B17/00; E21B17/02; E21B17/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
127 words
A bit for enlarging a pilot hole into a larger diameter hole by distintegrating earth formations surrounding the pilot hole, comprising: 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; a drive stem positioned in said central opening with a portion of said drive stem extending beyond said central opening; recess means on the portion of said drive stem extending beyond said central opening that provide said portion with a noncircular cross section; a retaining element positioned in said recess means, said retaining element being a two-piece collar adapted to be bolted to said main bit body; and means for attaching said retaining element to said main bit body.
Claim 2
Dependent Claim
127 words
A bit for enlarging a pilot hole into a larger diameter hole by distintegrating earth formations surrounding the pilot hole, comprising: 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; a drive stem positioned in said central opening with a portion of said drive stem extending beyond said central opening; recess means on the portion of said drive stem extending beyond said central opening that provide said portion with a noncircular cross section; a retaining element positioned in said recess means, said retaining element being a two-piece collar adapted to be bolted to said main bit body; and means for attaching said retaining element to said main bit body.
Claim 3
Dependent Claim
133 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; recess means on the portion of said drive stem extending below said central opeNing that provide said portion with a non-circular cross section; retaining element means positioned in said recess means, said retaining element means being a two-piece collar adapted to be bolted to said cutter stage plate; and means for attaching said retaining element means to said cutter stage plate.
Claim 4
Dependent Claim
133 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; recess means on the portion of said drive stem extending below said central opeNing that provide said portion with a non-circular cross section; retaining element means positioned in said recess means, said retaining element means being a two-piece collar adapted to be bolted to said cutter stage plate; and means for attaching said retaining element means to said cutter stage plate.
Claim 5
Dependent Claim
126 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: 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; a drive stem positioned in said central opening with a portion of said drive stem extending beyond said central opening; at least one flat on the portion of said drive stem extending beyond said central opening; a retaining element positioned in said at least one flat, said retaining element having a flat portion that fits against said flat and a connecting portion; and means for attaching said connecting portion of said retaining element to said main bit body.
Claim 6
Dependent Claim
126 words
A bit for enlarging a pilot hole into a larger diameter hole by disintegrating earth formations surrounding the pilot hole, comprising: 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; a drive stem positioned in said central opening with a portion of said drive stem extending beyond said central opening; at least one flat on the portion of said drive stem extending beyond said central opening; a retaining element positioned in said at least one flat, said retaining element having a flat portion that fits against said flat and a connecting portion; and means for attaching said connecting portion of said retaining element to said main bit body.
Claim 7
Dependent Claim
148 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; a recess on the portion of said drive stem extending below said central opening that provides the portion with a non-circular cross section; a retaining element positioned in said recess, said retaining element comprising a multiplicity of sections that at least partially surround said drive stem and prevent said drive stem from rotating in said central opening and being drawn through said central opening; and means for attaching said retaining element to said cutter stage plate.
Claim 8
Dependent Claim
148 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; a recess on the portion of said drive stem extending below said central opening that provides the portion with a non-circular cross section; a retaining element positioned in said recess, said retaining element comprising a multiplicity of sections that at least partially surround said drive stem and prevent said drive stem from rotating in said central opening and being drawn through said central opening; and means for attaching said retaining element to said cutter stage plate.
Claim 9
Dependent Claim
126 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a flange plate on said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; recess means on the portion of said drive stem extending below said central opening that provide said portion with a non-circular cross section; retaining element means positioned in said recess means; flange plate means on said retaining element means; and means attaching said flange plates together.
Claim 10
Dependent Claim
126 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 plate; a multiplicity of saddles mounted on said cutter stage plate; a multiplicity of rolling cutters positioned in said saddles; a central opening in said cutter stage plate; a flange plate on said cutter stage plate; a drive stem positioned in said opening with a portion of said drive stem extending below said central opening; recess means on the portion of said drive stem extending below said central opening that provide said portion with a non-circular cross section; retaining element means positioned in said recess means; flange plate means on said retaining element means; and means attaching said flange plates together.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |