Plug e.g. water drain plug, for screwing into housing opening in closure unit that is utilized for releasable closing of e.g. oil filter of motor car, has radial collar forming losing protection when plug is unscrewed from housing opening

摘要

The plug (1) has a screw fastening portion (2) extending into a screwing-in direction (S), where a locking portion (3) passes into the fastening portion in the screwing-in direction. External threads (4) are provided in a region of the fastening portion. A radial collar (5) is provided in the region of the locking portion and forms a losing protection when the plug is unscrewed from a housing opening. A conic tapered portion (6) is provided between the radial collar and the fastening portion and conically tapers towards the fastening portion. An independent claim is also included for a closure unit.