acting on the nut 19 the engagement of the element 2 with the internal surface of the tubular body of the lifting insert rigidly couples the lifting insert to the screw 18 and to any other elements associated with the screw 18 and with the element 2 such as the plate 14 or the plate 15 all these elements can be used to position and support the lifting insert in the formwork of the component 5 the engagement of the element 2 and of the optional disk 22 with the internal surface of the tubular body prevents with absolute safety the penetration of concrete during the molding of the component 5 in the region of the lifting insert that is designed to be engaged by the lifting element it should be noted that the plates 14 and 15 when provided generate recesses on the face of the prefabricated component 5 at the lifting insert 4 4 a said recesses are designed to be filled with castings of cement mortar in order to conceal the lifting inserts once the prefabricated component has been fully installed once the prefabricated component 5 has stabilized by acting on the screw 18 or on the nut 19 in reverse to what had been done earlier a radial contraction is achieved by elastic reaction.