Cap for containers

1 . A combination of a cap and a container,

the cap comprising an end wall, a skirt which extends about an axis, a corner zone interposed between the end wall and the skirt, the corner zone comprising a first wall portion which projects from the skirt towards the inside of the cap and a second wall portion which protrudes from the end wall and is joined to the first wall portion, the first wall portion and the second wall portion defining a step on a surface of the corner zone facing towards the outside of the cap,

the container comprises a neck, the neck having an end portion, an outer lateral surface and

an outer thread having an angular extension,

wherein the cap further comprises an annular sealing lip delimited by an inner surface configured to engage with the outer lateral surface of the neck of the container, wherein the annular sealing lip extends towards a free edge of the skirt from a region in which the first wall portion is joined to the second wall portion;

wherein the cap further comprises a plurality of outer ribs located in the corner zone,

wherein the outer ribs are the continuation of a plurality of knurling lines provided on the skirt,

wherein the annular sealing lip is the continuation of the second wall portion extending below a bottom edge of the second wall portion along axis (Z) towards the free edge and the annular sealing lip is positioned outside the end portion of the neck and the inner surface of the annular sealing lip is in contact with the outer lateral surface of the neck, and

wherein the cap further comprises an inner thread having an angular extension, the inner thread of the cap engaged with the outer thread of the neck and the angular extension of the inner thread of the cap is of different length from the angular extension of the outer thread of the neck.

2 . The combination according to claim 1 , wherein the annular sealing lip extends mainly parallel to the axis.

3 . The combination according to claim 1 , wherein the annular sealing lip has a thickness which decreases in a direction directed towards the free edge.

4 . The combination according to claim 1 , wherein the inner surface which delimits the annular sealing lip is curved.

5 . The combination according to claim 1 , wherein the end wall has a thickness of between 0.6 and 1.5 mm.

6 . The combination according to claim 1 , wherein the end wall has, in a central zone thereof close to the axis, a thickness different from the thickness of the end wall in a peripheral zone thereof close to the annular sealing lip, and wherein the difference between the thickness of the end wall in the central zone and in the peripheral zone is between 0.1 and 0.6 mm.

7 . The combination according to claim 1 , wherein on an inner surface of the skirt at least one anchoring element is provided for removably fixing the cap to a neck of the container.

8 . The combination according to claim 7 , wherein on the inner surface of the skirt at least one vent is provided to let escape from the container any gas during opening, the at least one vent being shaped like a recess that interrupts the at least one anchoring element and penetrates into the thickness of the skirt for a depth of less than 0.5 mm.

9 . The combination according to claim 1 and further comprising an inner sealing element which projects from the end wall towards the inside of the cap, the inner sealing element having an annular shape and being arranged in a position inside the annular sealing lip coaxially with the annular sealing lip.

10 . The combination according to claim 9 , wherein the inner sealing element is delimited by a convex sealing surface facing towards the annular sealing lip, the inner sealing element being intended to be positioned inside a neck of the container so that the convex sealing surface engages with a lateral inner surface of the neck.

11 . The combination according to claim 9 , and further comprising a front sealing element shaped like an annular protrusion which projects from the end wall in a position interposed between the annular sealing lip and the inner sealing element for engaging with a front edge of the neck.

12 . The combination according to claim 1 , intended to be applied to a container containing a carbonated drink, the cap having a weight of between 1.5 and 2.2 grams.

13 . The combination according to claim 1 , intended to be applied to a container containing a non-carbonated drink, the cap having a weight of between 1 and 1.8 grams.

14 . The combination according to claim 1 , wherein the inner thread of the cap has an angular extension about said axis that continues towards the free edge and beyond the outer thread on the neck.

15 . The combination according to claim 1 , wherein, when the cap is screwed to the neck, the angular extension of the inner thread of the cap continues towards the free edge and beyond the outer thread present on the neck, such that the difference of angular extension between the inner thread of the cap and the outer thread of the neck is 30° and 270°.

16 . The combination according to claim 1 , wherein, when the cap is screwed to the neck, the end of the angular extension of the inner thread of the cap extends beyond the end of the outer thread of the neck, towards the end wall, such that the difference of angular extension between the inner thread of the cap and the outer thread of the neck is 10° and 90°.

17 . The combination according to claim 1 , wherein the outermost diameter of the second wall portion is greater than the outer diameter of the annular sealing lip.

18 . The combination according to claim 17 , wherein the diameter of the inner surface of the annular sealing lip is equal to or smaller than the inner diameter of the second wall portion.

19 . The combination according to claim 1 , wherein the inner surface of the annular sealing lip curves towards the skirt at the bottom portion of the annular sealing lip to engage with an outer lateral surface of a neck of the container.

20 . The combination according to claim 1 , wherein the annular sealing lip is configured to bend towards the axis of the cap when the end wall deforms outward.