Abstract: The rivet includes a screw element which rotates within a body element. The body element includes an upper collar, integral with the body head, which is longitudinally stabilized with respect to the rotating screw element. The body element further includes a lower collar which is internally threaded and engages the external threads of the shank of the screw element. The lower collar therefore traverses a portion of the shank of the screw element as the screw element rotates. Folding legs join the upper collar and the lower collar. In the uninstalled position, the folding legs are parallel to and abut the screw shank. However, in the installed position, the lower collar approaches the upper collar and the legs fold so as to be substantially perpendicular to the screw shank.