Variable clamp means for seals

The device (1) has clamp lips (3) within the foot for pushing onto the flange and making a reversible joint between the foot and flange. An additional hinged and/or separable lip (4) is arranged on at least one side of the foot that can be folded into the foot with reducing flange thickness to compensate for the reducing thickness, whereby a maintainable joint is made between the foot and sheet.