Closing element

1. Closing unit for a throughflow opening of a beverage container, the closing unit comprising:

a first closing element configured to be mounted or integrally formed on the beverage container, wherein the first closing element comprises a receiving part comprising a wall, the receiving part provided with a passage and to be arranged in or round the throughflow opening, the throughflow opening being a drinking or pouring opening of the beverage container;

a second closing element comprising a closing part configured to be received by the receiving part and to be coupled releasably thereto for the purpose of closing or leaving clear the drinking or pouring opening;

wherein the wall of the receiving part comprises a conical screw thread disposed on its surface,

wherein the closing part of the second closing element comprises a substantially annular downward extending part with an external conical screw thread disposed on its outer surface,

wherein the downward extending part of the second closing element comprises a hollow space defined therein such that when the second closing element is engaged with the first closing element, the hollow space is exposed to the volume of the beverage container,

wherein the flexibility of the wall of the receiving part of the first closing element is lower than the flexibility of the downward extending part of the closing part of the second closing element such that when the second closing element is engaged with the first closing element, the downward extending part of the second closing element is configured to move in a radial direction against the wall of the first closing element due to the pressure inside of the beverage container, and

wherein the conical screw threads disposed on the first and second closing elements are configured to be threadbly engaged with each other such that the conical screw threads of the second closing element are pressed increasingly more firmly against the conical screw threads of the first closing element in a radial direction relative to a longitudinal axis of the hollow space defined in the second closing element as the pressure inside the beverage container increases.

2. Closing unit as claimed in claim 1 , wherein the apex angle (2β) of the cone of the conical screw thread amounts to between 5 and 20 degrees.

3. Closing unit as claimed in claim 1 , wherein conical screw thread disposed on the first and second closing elements is a multi-thread screw thread and the multi-thread screw thread is embodied to couple or uncouple the closing part and receiving part over substantially the whole periphery with a rotation of the closing part and receiving part relative to each other over an angle of less than 90 degrees.

4. Closing unit as claimed in claim 1 , wherein the ratio of the thread overlap O and the pitch S is smaller than 2*tangent (β), wherein β equals the half-apex angle of the cone.

5. Closing unit as claimed in claim 1 , wherein the closing part is embodied such that the unscrewing angle θ is approximately equal to:

( O* 180°)/( S *tan(β)),

with S being the thread pitch, β the angle of conicity, O the thread overlap and n the number of threads of the screw thread.

6. Closing unit as claimed in claim 1 , wherein the conical screw threads take a self-braking form and/or wherein, substantially irrespective of the magnitude of the axial force exerted on the closing element, the second closing element will not unscrew of its own accord.

7. Closing unit as claimed in claim 1 , wherein the entry angle α is equal to arc tangent (f) plus or minus 25%, wherein f is equal to the effective coefficient of friction between the conical screw threads of the first and second closing elements, in particular between two overlapping thread parts which support on each other or lie against each other and/or wherein the average entry angle α of the screw thread is such that the effective coefficient of friction between the screw thread of the first closing element and the screw thread of the second closing element is greater than the tangent of the entry angle α, wherein the average entry angle α is defined as:

α=arctan(pitch S /(π*average screw thread diameter)).

8. Closing unit as claimed in claim 1 , wherein the effective coefficient of friction between the screw thread of the first closing element and the screw thread of the second closing element is 15-30% greater than:

pitch S /(π*average screw thread diameter).

9. Closing unit as claimed in claim 1 , wherein a single-thread or multi-thread screw thread of the threaded coupling is arranged so as to engage on each other over the whole periphery of the receiving part and closing part.

10. Closing unit as claimed in claim 1 , wherein the entry angle (α) of the screw thread varies from a relatively high value close to the free outer end of the closing part and a relatively low value at the opposite outer end of the closing part.

11. Closing unit as claimed in claim 1 , wherein the thread overlap (O) of the conical screw threads of the first and second closing elements amounts to between 0.4 and 1.0 mm and/or wherein the pitch (S) of the screw thread amounts to between 8 and 20 mm.

12. Closing unit as claimed in claim 1 , wherein an intermediate element is arranged between the first closing element and the second closing element, wherein the intermediate element comprises:

a first element part coupled to the first closing element;

a third element part coupled to the second closing element; and

a second element part coupled to both the first and third element parts via a corresponding hinge,

wherein the

hinge coupling the second element part to the third element part is positioned opposite the hinge coupling the first element part to the second element part,

wherein the hinge coupling the first element part to the second element part is a bistable hinge configured to hold the closing unit in stable manner in either a closed position or an opened position, and

wherein the first, second, and third element parts are each concentrically disposed about the throughflow opening when the closing unit is in a closed position.

13. Closing unit as claimed in claim 12 , wherein the intermediate element is configured to pivot the closing part of the second closing element between a closed position substantially closing the passage in the first closing element with the closing part and an opened position substantially keeping open the passage in the first closing element.

14. Closing unit as claimed in claim 12 , wherein the closing part is mounted rotatably on the third element part and comprising screw thread which is formed on the closing part and which engages on corresponding screw thread of the first closing element during rotation of the closing part.

15. Closing unit as claimed in claim 1 , wherein the first closing element comprises at least a stop for limiting the angle of rotation of the closing part.

16. Closing unit as claimed in claim 1 , wherein the first closing element comprises a cover configured to accommodate at least a portion of the closing part of the second closing element and prevent removal of the closing part until the closing part has been rotated through a preset minimum angle relative to the first closing element.

17. Closing unit as claimed in claim 1 , wherein the first closing element and/or the second closing element are manufactured substantially or wholly from plastic and/or are constructed from injection-moulded components.

18. Beverage container provided with a closing unit as claimed in claim 1 .