Extension rods used in percussive drilling
US4051906A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1976 |
| Grant date | Oct 4, 1977 |
| Priority date | — |
| Expiry date | Mar 3, 1996 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/0426
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A percussive drill extension rod having first and second externally threaded ends, a rod zone therebetween, and a substantially round, internal bore in the threaded ends and rod zone along the longitudinal axis of the extension rod, with particular relative dimensions designed to improve performance and reduce costs. The first threaded end of the extension rod has an outside diameter (TD) in the range of about 1.25 to about 2.5 inches, and the rod zone has an outside diameter (RD) within a range from about equal to the outside diameter (TD) of the first threaded end to about 1.1 times the outside diameter (TD) of the first threaded end. The first threaded end has a cross-sectional area (TDX) derived from the specific outside diameter of the threaded end (TD) selected from the given range of about 1.25 to about 2.5 inches. The rod zone has an annular cross-sectional area (RX) equal from about 0.64 to about 0.76 times the circular cross-sectional area (TDX) based upon the outside diameter (TD) of the first threaded end, the internal bore in the rod zone having a diameter (RB) equal to 2 (.sqroot.(circular cross section (RDX) based on the outside diameter (RD) of the rod zone minus th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.