| 摘要 |
The present invention relates to a thread coupling including at least one male thread (10) and one female thread (17), said male thread (10) being arranged upon a spigot (11) that constitutes an integral part of a first drill string element (12), and said drill string element (12) at the inner end of said spigot (11) being provided with a shoulder (13) that has a contact surface (14) directed towards the free end of the spigot (11), said female thread (17) being a part of a coupling sleeve (18) that is connected to a second drill string element (19), and the coupling sleeve (18) being provided with an internal stop surface (20). In thread couplings between drill string elements either so-called bottom stops or so-called shoulder stops are used, said principles per se having disadvantages as to stresses, energy transfer and so on. The characteristic of the present invention is the combination of a bottom and a shoulder stop in a thread coupling. |
