Abstract: A method for joining at least two plastic elements in a liquid- and/or gastight manner, whereby an edge of a first plastic element is at least partially placed in an opening of a second plastic element, the edge of the first plastic element being folded over an edge of the opening of the second plastic element under plastic deformation, using a pressure device. The edge of the first plastic element is pressed against a curved butting face of a pressure body placed in the second plastic element at the opening thereof and the edge of the first plastic element along the butting face is pushed radially outwardly and over the edge of the opening of the second plastic element. The edges of both plastic elements are pressed together by exerting pressure on both sides of the edges. Alternatively, use is made of a sealing ring at least partially between the edges.

Abstract: Sealing ring of an elastic material, for use in a pipe coupling in which the ring is placed in a radially inwardly open peripheral groove and is retained in said groove by means of a supporting ring(6) which sealing ring in each radial cross-section is the shape of an inwardly open, essentially rectangular trough with a circular bottom (2), a projecting lip (8) being provided which runs inwards at an angle from the end of the first circumferential wall of the trough, the free end of which lip lies at a radial distance from the axis of symmetry of the ring which is smaller than the external radius of the push-in end part of a pipe to be coupled and at the end of the second side wall of the trough, the free end of which lip lies at a greater distance from the above-mentioned axis than the free end of the first lip, the second lip being provided with a run-on face (10) which runs from a point near the bottom of the lip in the direction of that axis to an end point which lies at a distance from the axis which is