US Patent 10285738 Polyaxial ball and socket fastener with spot welded blocking ring

The bottom loading fastening system that consists of the polyaxial ball and socket joint used in conjunction with a bone screw. The system allows attachment to a bone screw using a retaining ring spot welded to a blocker ring to assure proper ring positioning. Upon installation the retainer wall is expanded causing a break from the blocker ring producing an audible and tactile indication that the sufficient force has been applied to set the retainer and blocker rings locking the bone screw to a U-shaped connecting assembly.