| 摘要 |
The thread coupling is provided with a male thread (4) and a female thread (5) cooperating therewith. The male thread is arranged on a first drill string element (3) provided with a first impact surface (6). The female thread is arranged on a second drill string element (2) which is provided with a second impact surface (7). The male thread (4) has an axially variable pitch. And the female thread (5) has a thread opening (8) which is wider than the crest (9) of the male thread. |
