A hinged cover overlays an opening that provides access to a pressurized inversion drum. A releasable latch assembly holds the cover in a closed and locked position. The latch assembly comprises a plurality of first knuckles formed in the cover that are interlaceable with a plurality of second knuckles formed in the body adjacent the opening. The latch assembly further comprises a rotatable latch pin that may be installed within the first and second knuckles. The latch assembly is moved from an unlocked to a locked position by rotation of the latch pin within the knuckles.