At least one connection assembly which this equipment comprises includes a connection piece of open type and a mating component piece positioned one with respect to the other by positioning means. According some disclosed embodiments, the said positioning means include: the hole in the said connection piece； a portion of the said piece, dimensioned so as to be engaged in the interior of this hole in a fit adjusted manner and so as to be slidable in this hole； and the said connection assembly comprises: assembly means for assembling of the connection piece to the mating component piece, and maintaining means for maintaining in place the said mating component piece in the said separated apart position, based on a force that is less than the clamping force exerted by a nut to be screwed on to the proximal threaded pin of an anchoring member.
