| 摘要 |
An expandable coupling consists of a first male or pin portion 16 and a second female box portion 18, each portion comprising a plurality of inter-engaging teeth 20, 22. At least one tooth on each portion engages each other, with the remaining teeth having gaps between them. In one embodiment, the teeth have flanks 30, the flanks of at least one tooth of each of the pin and box portions abutting one another, with gaps 32 between the corresponding flanks. The gaps between the teeth may vary along the length of the thread, and this variation may be achieved through the use of a variable thread pitch. The teeth may have a dove tail profile, or a square profile, and the gaps may be filled with deformable sealing material 40. Once positioned, the coupling may be expanded by numerous means, such as by hydraulic pressure, or by a cone expansion tool. |
