ENERGY TRANSMISSION EFFICIENT DRILL STRING COUPLING

摘要

A drill string and a threaded coupling region for a drill string in which a threaded male and female end are optimised to maximise energy transmission efficiency for percussion drilling. The present coupling includes a male spigot to be received within a female sleeve such that an axial length of the overlap of the spigot within the sleeve is less than an outside diameter of the sleeve.

主权项

1. A drill string for percussive drilling comprising:
a first elongate drill string member having a main section and a male end; a second elongate drill string member having a main section and a female end; an outside diameter of the female end being greater than an outside diameter of the main section thereof and an outside diameter of the male end having an outside diameter that is approximately equal to an outside diameter of the main section thereof; and the male and female ends having respective threads to enable the male end to be secured inside the female end such that an axial length of the male and female ends overlap axially, wherein the axial length of the overlap is less than an outside diameter of the female end.