Rolling cone bit with shear cutting gage
US5287936A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1992 |
| Grant date | Feb 22, 1994 |
| Priority date | — |
| Expiry date | Jan 31, 2012 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/5673
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A cutter of an earth-boring bit is provided with hard gage inserts that protrude from the gage surface of the cutter to engage the side of the borehole for holding gage. The gage insert has a substantially flat face with sharp cutting edges formed thereon and has cutting surfaces that define a negative rake angle with respect to the sidewall of the borehole that is being sheared by the gage insert. The face, cutting edge, and cutting surface of the gage insert are formed of a super-hard and abrasion-resistant material such as polycrystalline diamond or cubic boron nitride. The body of the insert is formed of a hard, fracture-tough material such as cemented tungsten carbide. The improved gage inserts are secured into sockets in the gage surface of the rolling cone cutter by interference fit. The improved gage inserts provide an actively cutting gage surface that engages the sidewall of the borehole to promote shearing removal of the sidewall material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.