| 摘要 |
Box and pin of lift pipes column comprises a stand, connector and junction box, those are connected between them by tool-joint thread. The ends of stands are correspondingly connected to outer ends of the connector and junction box by means of interference fit. In mounting surface area circle-wise with uniform spacing cylinder fit openings are formed, to which conical bolts tightened with nuts are set on from the inner pipe space, ends of the stand are expanded to annular grooves formed in each element of the joint, and the ends of those are welded to the pipe body. |
