| 摘要 |
<p>The present invention relates to a method of extending the length of a drill string. It also relates to a drill string element and to a coupling member. It further relates to a shank rod and to a drill string. The drill string element includes an elongate shank having a leading end and a trailing end; a collar provided on the shank intermediate the leading end and the trailing end, at least part of the shank between the trailing end and the collar being receivable in a hammer and being of non-circular cross section for at least part of its length; and connecting formations at the leading end and trailing end of the shank of the drill string element whereby the drill string element is connectable end-to-end to a similar drill string element.</p> |
