Self-locking Insert

A nonmetallic unthreaded item generally round in cross-sectional shape which, when placed on/in a machined-out portion of the threads of a screw or bolt, or inserted into the machined-out portion of the threads of a nut, locks the item, to which it is fixed, to the attached mating member and prevents loosening during excessive vibration. Excludes bolt, self-locking; nut, self-locking (as modified); screw, self-locking; and insert, screw thread.