Seal plug or bush for installation boxes - has sealing lip on either male or female thread cooperating with mating part

摘要

The plug (1) has a head (3) larger than the shank and forming a seating shoulder (8) on its under surface. The shank is provided with a thread (2) terminating a short distance from this shoulder. In this area is an annular sealing lip (4), solid with the shank and having a section narrowing to a joint on its outer diameter (D), greater than the thread (d). When screwed into place, the lip, being flexible, seals inside the top threads. The shoulder of the plug is tight on the mating surface and improves its resistance to loosening. The lip can equally be provided in the female thread.