Closing Device Comprising a Non-Continuously Circular Cutting Ring

A multipart plastic closing device attachable over a receptacle, comprising a bung-shaped bottom part (3) with a cylindrical pouring spout (9) which is connected or connectable to the receptacle, and a closing cap (2) which is sealingly placeable on the spout (9) of the bottom part (3), as well as a cylindrical cutting ring (1) which is open on both sides in an axial direction and is helically movably provided in the spout (9) of the bottom part (3), with in the closing cap (2) there being provided at least one means (16) which acts on the cutting ring (1) during an unscrewing movement of the closing cap (2), characterised in that the cutting ring (1) is not continuously circular, but in at least one place forms a recess (6) which co-operates as a driver with at least one associated axially running driving cam (16) present in the closing cap cover (27) when said cam engages in the inside of the recess (6), or as a stop when from inside the cutting ring (1) and outside the recess (6) it hits the latter, as a result of which the cutting ring (1) during an unscrewing movement of the closing cap (2) due to the positively fitting means (5, 13) moulded to the inner wall of the cylindrical pouring spout (9) of the bottom part (3) and to the outside of the cutting ring (1) is displaceable into a helical downward-leading movement during the initial unscrewing movement of the closing cap (2), and that the underside of the cutting ring (1) has a sharp cutting edge (4) which with the bottom edge (29) of the cutting ring (1) encloses an obtuse angle (21), and that the axial recess (6) on the cutting ring (1) acts as an ventilation duct (26) when the contents are poured out.