Drill string element
US4961469A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1989 |
| Grant date | Oct 9, 1990 |
| Priority date | — |
| Expiry date | Apr 24, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/00
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drill string element for use in top hammer percussive drilling comprises first and second tubes coupled together by a cylindrical thread, and at least one impact-transmitting ord slidably disposed in the tubes. The rod(s) includes abutments which engage restrictions formed at remote ends of the tubes whereby the rod(s) can be removed only by unscrewing the tubes from one another. Remote ends of the tubes define male and female conical threads which enable the element to be connected to similar elements in the forming of a drill string. The conical threads are easier to unscrew than the cylindrical threads to avoid an accidental separation of the tubes of each element when that element is being unscrewed from another element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.