Sealing structure for a rock drill bit
US6578647B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 2001 |
| Grant date | Jun 17, 2003 |
| Priority date | — |
| Expiry date | Jul 25, 2021 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/25
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A sealing structure for a rock drill bit includes an elastomeric diaphragm for installation in the drill bit so as to separate grease from drilling mud. The diaphragm has an aperture extending through it, and a plug is disposed in the aperture so as to form a mechanical seal with a wall of the aperture. The plug has a channel therethrough which is normally held sealed by a face of the aperture in the diaphragm. If the pressure of the grease exceeds pressure in mud on the other side of the diaphragm by more than a critical value, the diaphragm aperture deforms and allows grease to move through the plug channel and escape. The critical value can be varied by using, with the same diaphragm, plugs having different numbers, sizes and axial positions of plug channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.