| 摘要 |
The invention relates to rod or casing elements (1) used in drilling rigs, wherein it comprises a threaded part (3) on the female port (2) part and male port (4) part on the rod or casing element (1), and minimum one thread starting port (6) on the threaded part (3) formed in the thread start (5) part in order to eliminate probable thread bite and jamming problems. |
