| 摘要 |
This apparatus comprises: - a first box 9 fixed to the slideway, inside which there is mounted a set of jaws 34 centred on to the axis of the string of drill elements 25 and capable, in the tightened position, of immobilising an element of this string, - a second box 15 located above the first one 9 and capable of moving in translation and in rotation about the axis of the string, and able, in the tightened position, to be attached to the element of the drill string adjacent to that blocked by the first box, - means for providing for a combined movement of translation and of rotation of the second box along a circular helix of pitch corresponding to the screw threads allowing the assembly of two elements. <IMAGE>
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