Drill bit having polycrystalline diamond compact cutter with spherical first end opposite cutting end
US5333699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1992 |
| Grant date | Aug 2, 1994 |
| Priority date | — |
| Expiry date | Dec 23, 2012 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/5673
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drag bit having a plurality of blades or ribs on its end face has one or more pockets milled into the top surfaces of said blades using a ball nosed end mill to create a plurality of pockets, each having a spherical or a semi-spherical first end and a second end having a semi-circular configuration which intersects with the leading edge face of the rib. A bullet-shaped cutting structure having a spherical first end is brazed into each of the pockets. During the manufacturing process, a pin is brazed into cooperating first and second semi-circular receptacles in the spherical end of the cutter and in the semi-spherical end of the pocket, respectively, to prevent the cutter assembly from being pushed up out of the pocket during the drilling operation. In an alternative embodiment, a slot is milled into the top surface of the rib to allow use of a ball nosed end mill having a reduced diameter shank sized to pass through the slot. In yet another embodiment, a tungsten carbide button or insert is position at the gauge diameter to reduce impact on the gauge diameter cutter in each of the ribs. Cutter assemblies are disclosed having a variety of orifices in the PDC cutter face to functi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.