Abstract: The invention relates to a securing device (10) for a structure (11) having an open-ended cylindrical bore (13a), the securing device comprising: an insert (15) comprising a tapped tubular body (16) and a head (18), the extremity (20) of the body opposite the head comprising an annular cavity holding a ring (21) made of a plastic material; a pin (22) comprising a cylindrical tapped rod (16) assembled with the tapping of the insert and a head (23), the extremity (30) of the cylindrical threaded rod being tapered; the device being characterized in that the threaded rod is introduced into the insert on the ring side such that, in the assembled state, the head of the insert and the head of the pin form the terminal ends of the securing device (10). The invention also relates to an assembly for the installation of such a device, and also to an installation method.