Closure cap of plastic material

A closure cap of plastic material comprising a female screwthread (2) for closing a mouth (3) of a container having a male screwthread (4), wherein at its lower edge (5) the cap has a substantially circumferentially continuous guarantee strip (6) which can be torn off and which is provided on the inside (7) with at least one retaining element which, when the cap is screwed on, engages under an annular projection (8) at the mouth of the container, the improvement wherein said at least one retaining element comprises:

• a detent edge portion (9) which extends generally continuously around substantially the entire inner circumferential surface of the guarantee strip and which engages under the annular projection (8) in one plane over substantially its entire periphery and whose inside diameter is smaller than the inside diameter of the lower edge of the cap so as to be smaller also than the outside diameter of the projection, and
• at least one circumferentially intermittent holding projection (10) which projects inwardly towards the centre of the cap and which is disposed substantially in the plane of the detent edge portion (9), and
• a bead which projects inwardly from the inner surface of the guarantee strip at the detent edge portion and strengthens the detent edge portion.

In combination, a container having a male screwthread, and a closure cap of plastic material for closing a mouth of the container, the closure cap having at its lower edge a substantially circumferentially continuous guarantee strip which can be torn off and which is provided on the inside with at least one retaining element which, with the cap screwed on, engages under an annular projection at the mouth of the container, the improvement wherein the at least one retaining element comprises:

• a detent edge portion which extends generally continuously around substantially the entire inner circumferential surface of the guarantee strip and which engages under the annular projection in one plane over substantially its entire periphery and whose inside diameter is smaller than the outside diameter of the annular projection, and at least one circumferentially intermittent holding projection which projects inwardly toward the center of the cap and which is disposed substantially in the plane of the detent edge portion, said holding projection projecting inwardly from the area of said detent edge portion over a relatively small part of the circumference of the detent edge portion.