Earth-boring bit with improved cutting structure
US5479997A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1994 |
| Grant date | Jan 2, 1996 |
| Priority date | — |
| Expiry date | Aug 19, 2014 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/52
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An earth-boring bit has a bit body and at least one cutter rotatably secured to the bit body. The cutter has a cutter shell surface including a gage surface intersecting a heel surface. A plurality of hard metal inserts are arranged in generally circumferential rows on the cutter and include a heel row of heel inserts on the heel surface of the cutter and a gage row of gage inserts on the gage surface of the cutter. At least one scraper insert, formed of material more wear-resistant than that of the cutter shell surface, is secured to the cutter shell surface generally at the intersection of the gage and heel surfaces. The scraper insert includes a gage and a heel insert surface. The gage and heel surfaces of the scraper insert converge to define a cutting edge for engagement with the sidewall of the borehole, the heel insert surface defining a positive rake angle with respect to the sidewall of the borehole of between 0 and 15 degrees. The cutting edge projects from the heel surface an amount not greater than the lesser of one-half the projection of the heel inserts from the heel surface and 30% of the pitch between the heel inserts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.