Patent ID: 7347338

Claim:
A method for closing an opening, comprising a) providing a plug of elastic material, an outside diameter (r L ) of the plug in a static state being larger than a diameter (r p ) of the opening to be closed, and which plug has, at its end, a cavity and optionally a flange, protrusion or groove, the diameter of which is substantially larger than the diameter (r p ) of the opening to be closed, b) releasably attaching an extending device to the plug, wherein the extending device comprises an extending element that can be moved between an extended and a retracted position i) by inserting the extending device into the cavity of the plug to such an extent that the plug is stretched to a first stretched position in which the plug is pressed around the extending device so tightly that the plug remains releasably attached to the extending device, or ii) by gripping the flange, protrusion or groove of the plug with a gripping means of the extending device, c) in a separate step subsequent to step b), stretching the plug to a second stretched position by moving said extending element to its extended position, such that the plug's outside diameter (r V ) becomes smaller than the diameter (r p ) of the opening to be closed, d) inserting the extended plug into the opening to be closed, and e) reducing the plug's extension to such an extent that the plug closes the opening and adheres to it so tightly that the extending device is removed from the plug i) either by pulling, or ii) by means of a detaching element of the plug associated with the extending device.