Claims
- 1. A pilot mill, comprising:a mill head structure; a core breaking mechanism having a core passage and a breaking mechanism; and the core breaking mechanism located within the mill head structure, wherein the core passage extends in an arcuate radial path within the mill head structure, the curve of the arcuate radial path of the core passage extending in the direction of rotation of the pilot mill.
- 2. The pilot mill of claim 1 wherein:the mill head structure has a mill nose and an outer guided periphery; and the core passage extends from the mill nose to the outer guided periphery.
- 3. The pilot mill of claim 2 wherein:the breaking mechanism comprises a diverting slope within the core passage; and the diverting slope diverts the core passage from being substantially parallel to the axis of rotation of the pilot mill to being directed generally towards the outer guided periphery.
- 4. The pilot mill of claim 1 wherein:the breaking mechanism is located within the core passage.
- 5. The pilot mill of claim 1 wherein:the breaking mechanism comprises a diverting slope within the core passage.
- 6. The pilot mill of claim 1 wherein:the core passage comprises an drift core opening.
- 7. The pilot mill of claim 6 wherein:the mill head structure has a mill nose and an outer guided periphery; and the drift core opening has a first end at the mill nose and a second end at the outer guided periphery.
- 8. The pilot mill of claim 1 wherein:the mill head structure has a tapered milling surface; and the core passage comprises a core channel that is open to the tapered milling surface.
- 9. The pilot mill of claim 8 wherein:the mill head structure further has a mill nose and an outer guided periphery; and the core channel extends from the mill nose to the outer guided periphery.
- 10. A method for milling, comprising:providing a pilot mill having a mill head structure and a core breaking mechanism, the core breaking mechanism comprising a core passage extending in a curved radial path and a breaking mechanism and located within the mill head structure; rotating the pilot mill in a first direction, a curve of the curved radial path of the core passage extending in the first direction; receiving a core of non-milled surface within the core passage; and breaking the core of non-milled surface with the breaking mechanism.
- 11. The method of claim 10 wherein:the receiving step comprises continuously receiving the core of non-milled surface within the core passage.
- 12. The method of claim 10 wherein:the breaking step comprises continuously breaking the core of non-milled surface with the breaking mechanism.
- 13. The method of claim 10 further comprising:ejecting the broken core of non-milled surface from the pilot mill.
- 14. The method of claim 10, wherein the curved radial path comprises an arcuate radial path, and wherein rotating the pilot mill comprises rotating such that the curve of the arcuate radial path extends in the first direction.
- 15. A mill comprising:a mill head structure rotatable in a first direction; and a core breaking mechanism having a core passage extending radially along a curve, the curve of the core passage extending in the first direction.
- 16. The mill of claim 15, wherein the core passage extends in an arcuate radial path.
- 17. The mill of claim 16, wherein the core breaking mechanism further comprises a breaking mechanism in the core passage.
Parent Case Info
This application is a continuation-in-part and claims priority of U.S. patent application Ser. No. 09/293,821 filed by Ohmer on Apr. 16, 1999, now U.S. Pat. No. 6,209,645.
US Referenced Citations (33)
Non-Patent Literature Citations (1)
Entry |
Defourny, P.M. and Abbassian, Fereidoun; Flexible Bit: A New Antivibration PDC-Bit Concept; SPE Drilling & Completion; Dec. 1998; pp. 237-242. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09/293821 |
Apr 1999 |
US |
Child |
09/518350 |
|
US |