| 摘要 |
Equipment for a joinable drill stem of the type comprising a plurality of threaded rods intended for being joined together by means of internally threaded joining sleeves 12, whereby the formed thread joints in the two ends of such a sleeve 12 have different loosening properties. In this connection, the end with the joint difficult to loosen will be screwed right home, differently from the other end which forms the easily loosened joint, whereby the sleeve 12 will be left tightly joined to the rod end 10 which is screwed right home, when the drill stem is dismantled. <IMAGE> |
