Abstract: A self-locking plug assembly includes ratchet ring circumscribing body having centerline and shank having a threaded top portion. Flexible fingers spiral away from periphery of ratchet ring to engage polygonal sides of polygonal sided ring attached to body. Hooks may extend radially outwardly and downwardly from periphery of ratchet ring. Spring around polygonal portion of body rests on ratchet ring. Annular retaining ring snapped into annular groove in body compresses spring. Hooks may engage notches in the upper wall. Alternatively, hooks may include paws extending inwardly from downwardly extending legs of hooks and into the pockets and engaging upper pocket walls to axially secure the ratchet ring. Body may be borescope plug with a lower end of shank conforming to lower port opening in upper wall. Alternatively, flexible fingers extend outwardly from radially outer rim of ratchet ring and engage polygonal sides of inner side of polygonal sided ring circumscribing ratchet ring.

Abstract: A self-locking plug assembly includes ratchet ring circumscribing body having centerline and shank having a threaded top portion. Flexible fingers spiral away from periphery of ratchet ring to engage polygonal sides of polygonal sided ring attached to body. Hooks may extend radially outwardly and downwardly from periphery of ratchet ring. Spring around polygonal portion of body rests on ratchet ring. Annular retaining ring snapped into annular groove in body compresses spring. Hooks may engage notches in the upper wall. Alternatively, hooks may include paws extending inwardly from downwardly extending legs of hooks and into the pockets and engaging upper pocket walls to axially secure the ratchet ring. Body may be borescope plug with a lower end of shank conforming to lower port opening in upper wall. Alternatively, flexible fingers extend outwardly from radially outer rim of ratchet ring and engage polygonal sides of inner side of polygonal sided ring circumscribing ratchet ring.