Patent ID: 6959733

Claim:
A plug for closing a hole in a flat structural member in a sealing and acoustically dampening manner, said plug comprising: a shank which is adapted to be sealingly inserted into the hole and retained in the hole by an undercut cooperating with a wall of the hole; and a radial flange integrally formed at one end of the shank of resilient material, the flange having a radially outwardly oblique or bent portion which is adapted to sealingly engage an associated surface of the structural member upon deformation when the shank is inserted into the hole; wherein the shank, in an area of sealing engagement with the hole, has a sealing portion which, in a non-biased state, has a smooth conical outer surface, the outer surface having a diameter which increases towards the flange at least in the area of sealing engagement and is larger than that of the hole; a free space is provided on an inner side of a juncture of the flange and the shank, said free space extending axially towards the other end of the shank up to or beyond the area of sealing engagement, whereby an annular shank portion is formed beneath the flange, and, when the shank is pressed into the hole, a material of the annular shank portion is deformable into the free space and the wall of the hole causes an annular groove in the annular shank portion, the groove defining the undercut; radially inwardly of the flange the shank is connected with a bead portion, and the free space is formed by an annular recess of the head portion; and the head portion has an upper surface extending upwardly beyond the flange.