Rolling cone steel tooth bit with enhancements in cutter shape and placement
US5839526A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1997 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Apr 4, 2017 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/52
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A steel tooth bit includes one or more rolling cone cutters having a generally conical surface, a heel surface, and preferably a transition surface therebetween. A row of gage cutter elements are secured to the cone cutter on the transition surface and have cutting surfaces that cut to full gage. A first inner row of off-gage steel teeth is positioned on the conical surface of the cone cutter so that the gage-facing cutting surfaces of the teeth are close to gage, but are preferably off-gage a distance D at a knee that is formed on the gage facing surface. Distance D is strategically selected such that the gage and off-gage cutter elements cooperatively cut the corner of the borehole. The lower most portion of the gage facing surface of these steel teeth are off gage a distance D' which is greater than D so as to bring the cutting tip of the teeth off gage to prevent undesired wear and rounding off of the tip of the cutter element. The upper most portion of the gage-facing surface is also preferably off gage a distance D" that is greater than D so as to optimize the surface area on the gage facing surface that is in contact with the borehole corner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.