Plastic closing device with a piercing element

A closure device (1) of plastic, which can be applied over a spot, which can be punctured, of a closed container (B), consisting of a spout-shaped lower element (2) with a cylindrical pouring spout (20), and is or can be connected with the container, and a screw cap (4), which can be screwed on the lower element (2), as well as a cylindrical piercing element (3), open at both ends in the axial direction and displaceably seated in the lower element, in which means (44, 45) are provided in the screw cap (4) which, in the course of an unscrewing movement act on the piercing element, wherein the latter is moved downward into the container through the spot (S) which can be punctured, characterized in that on its cylindrical inner wall (30) the piercing element (3) has at least one catch element (34), which acts together with at least one catch rib (45) or catch groove (44) provided in the screw cap (4) and which in the course of a rotating movement of the screw cap (4) puts the piercing element (3) into a rotating movement, and that positive connecting means (24, 31) are provided between the cylindrical pouring spout (20) of the lower element (2) and the cylindrical piercing element (3), which move the pouring spout (20) downward in a helical manner during the first unscrewing movement of the screw cap.