US Patent 11174888 Threaded pin

A threaded pin comprises a threaded cylindrical stem that extends between a proximal stem end and a distal stem end, and a coupling end portion that extends from the distal stem end. In the coupling end portion, at least one annular groove is formed, which is distally delimited by a distal annular ridge that defines a maximum outer diameter of the coupling end portion. The maximum outer diameter of the coupling end portion is smaller than the inner diameter of the threaded cylindrical stem in such a way that the coupling end portion may be inserted with play into a threaded hole wherein the threaded pin may be screwed, the distal annular ridge being suitable for insertion between the ridges of the female thread of the threaded hole.