Rotary drill bit
US4538691A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 30, 1984 |
| Grant date | Sep 3, 1985 |
| Priority date | — |
| Expiry date | Jan 30, 2004 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/04
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A rotary drill bit includes a cutting face having a peripheral edge and a central recess. A plurality of fluid discharge nozzles are mounted in the cutting face. A plurality of cutter elements are mounted in the peripheral edge and in the recess to fracture an earthen core formed as the drill cuts through a formation. A plurality of lateral discharge passages extend radially through the bit body from said recess and extend longitudinally to the peripheral edge to form circumferential interruptions in the peripheral edge. A convex protrusion is disposed centrally at a longitudinally inner end of the recess and includes a convex deflecting surface arranged to contact and fracture the earthen core and deflect the cuttings to the lateral discharge passages. A ridge is disposed along a trailing edge of each of the discharge passages to retard the flow of drilling fluid into the associated discharge passage from an adjacent one of the nozzles, whereby such fluid is caused to flow across cutter elements located behind the ridge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.