Patent US3633691A successfully refreshed from Google Patents.
US3633691A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Large-diameter earth boring bit
Assignee: Dresser Industries Inc
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Filing: 1970-03-09
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Granted: 1972-01-11
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Expires: 1990-03-09
Abstract
Abstract A bit for drilling large-diameter holes. Cutters are arranged in a staged configuration around a central shaft. The innermost cutters are the same large cutters used at other locations on the bit allowing complete interchangeability. The innermost cutters are turned inward. This reduces the uncut bottom next to the pilot hole and provides a stronger bit because the central shaft has not been weakened by milling or other operations.
Inventors
- 👤 Milton L Talbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:30
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/26; E21B10/28; E21B10/08; E21B10/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
126 words
A bit for enlarging a pilot hole into a large-diameter hole comprising: a central shaft having a central longitudinal axis; a main bit body attached to said central shaft, said main bit body including a plurality of drilling stages progressively increasing in size; the first of said drilling stages including a pair of rolling cutters, removably mounted in a corresponding pair of saddles, the axis of rotation of said rolling cutters turned inward at an acute angle to the central longitudinal axis of said shaft; and a second pair of rolling cutters, removably mounted in a corresponding second pair of saddles, the axis of rotation of said second pair of rolling cutters turned outward at an obtuse angle to the central longitudinal axis of said shaft.
Claim 2
Dependent Claim
126 words
A bit for enlarging a pilot hole into a large-diameter hole comprising: a central shaft having a central longitudinal axis; a main bit body attached to said central shaft, said main bit body including a plurality of drilling stages progressively increasing in size; the first of said drilling stages including a pair of rolling cutters, removably mounted in a corresponding pair of saddles, the axis of rotation of said rolling cutters turned inward at an acute angle to the central longitudinal axis of said shaft; and a second pair of rolling cutters, removably mounted in a corresponding second pair of saddles, the axis of rotation of said second pair of rolling cutters turned outward at an obtuse angle to the central longitudinal axis of said shaft.
Claim 3
Dependent Claim
40 words
The bit of claim 1 wherein the second of said drilling stages includes a plurality of rolling cutters removably mounted in a corresponding plurality of saddles, the axis of rotation of said rolling cutters turned outward at an obtuse angle.
Claim 4
Dependent Claim
15 words
The bit of claim 2 wherein all of said rolling cutters are the same size.
Claim 5
Dependent Claim
18 words
The bit of claim 3 wherein said acute angle is within the range of from 45* to 90*.
Claim 6
Dependent Claim
155 words
A bit for enlarging a small-diameter pilot hole into a large-diameter hole comprising: a central shaft having a central longitudinal axis, said central shaft having an upper end adapted to fit within the pilot hole; a main bit body attached to said central shaft, said main bit body having a diameter larger than the diameter of the pilot hole; a plurality of drilling stages positioned on the main bit body, said drilling stages progressively increasing in size; the first of said drilling stages including a pair of rolling cutters, removably mounted in a corresponding pair of saddles, the axis of rotation of said rolling cutters turned inward at an acute angle to the central axis of said shaft; and the record of said drilling stages including a plurality of rolling cutters removably mounted in a corresponding plurality of saddles, the axes of rotation of said plurality of rolling cutters turned outward at an obtuse angle.
Claim 7
Dependent Claim
155 words
A bit for enlarging a small-diameter pilot hole into a large-diameter hole comprising: a central shaft having a central longitudinal axis, said central shaft having an upper end adapted to fit within the pilot hole; a main bit body attached to said central shaft, said main bit body having a diameter larger than the diameter of the pilot hole; a plurality of drilling stages positioned on the main bit body, said drilling stages progressively increasing in size; the first of said drilling stages including a pair of rolling cutters, removably mounted in a corresponding pair of saddles, the axis of rotation of said rolling cutters turned inward at an acute angle to the central axis of said shaft; and the record of said drilling stages including a plurality of rolling cutters removably mounted in a corresponding plurality of saddles, the axes of rotation of said plurality of rolling cutters turned outward at an obtuse angle.
Claim 8
Dependent Claim
12 words
The bit of claim 5 wherein all cutters are the same size.
Claim 9
Dependent Claim
18 words
The bit of claim 5 wherein said acute angle is Within the range of from 45* to 90*.
Claim 10
Dependent Claim
12 words
The bit of claim 5 wherein said acute angle is approximately 57*.
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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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |