Abstract: An assembly includes an elastic protection sleeve (211); two tubular cores (212, 212?) for holding the sleeve (211) expanded; for each tubular core (212, 212?), a slide film (213, 213?) placed between the sleeve (211) and the each core (212, 212?), to enable each core to slide relative to the sleeve; and a device (30) for holding the two cores (212, 212?) in order for them to be able to move apart from each other, from the initial state in which they are end to end, until they are apart at most by a predetermined distance at which the inside diameter of the sleeve (211) between the first ends (217, 217?) is at least similar to the inside diameter of the cores (212, 212?), whereby the assembly (210A) with the two cores (212, 212?) thus apart can still be repositioned.