The invention relates to a closing unit for closing a throughflow opening provided in a wall of a container, particularly a beverage container such as a can. The invention also relates to a wall of such a container which is configured for mounting of such a closing unit, and to the container itself.

The container can be suitable for storing random liquid or gaseous substances or solid substances. A container can for instance be formed by a bottle, flask, a car radiator, an oil reservoir of an engine, a petrol tank or the like.

Numerous different types of container are known for the purpose of storing liquid substances, in particular optionally carbonated beverage, or solid substances including particles which can be sprinkled or poured. A commonly used type of container is a beverage can. Cans are substantially cylindrical containers of metal (particularly tin), wherein a metal press-in tab is mounted in one of the end walls of the container which serves as temporary closure of the drinking or pouring opening formed in the container.

Such a closure of a can is generally known and is applied in substantially all beverage cans. A drawback of the known closure is that, once the press-in tab has opened the pouring or drinking opening, this opening can no longer be closed. Once the can has been opened, it must thus in general be wholly emptied, and safe storage of the content of an already opened can is not readily possible in practice. In order to obviate this drawback constructions have been proposed in which the closing element is embodied such that it can reclose the drinking or pouring opening.

These constructions practically all have the drawback however that the closure is not always very effective, and leakage may therefore occur. The closures are moreover often only suitable for closing the container when carbonated beverage is not arranged in the container. If a container with a carbonated content is shaken, for instance during transport (for instance distribution) of the beverage, a great pressure build-up can occur in the container such that the closure tends to start leaking. There can also be a high rise in the pressure in the container (for instance up to 5 atm or higher) in the manufacturing process and/or the filling process of such containers, for instance during a possible pasteurization step.

Known from the patent publication WO 2015/041528 Al is a closing unit in which a simple, good, easily opened and closed closure between the closing unit and the container can be realized by means of a particular type of threaded coupling. This known closing unit is however still relatively expensive to manufacture in large numbers. The known closing units are moreover often manufactured together with the end wall of the container (for instance with an injection moulding process in a single mould) via an in-mould technique. This can sometimes result in logistical drawbacks and/or produce a relatively thick closing unit. Due to the manufacturing process, the options for manufacturing the closing units from two or more materials with different properties (for instance soft/hard) are further limited and/or the closing units are relatively wide, necessitating a relatively large amount of space between the edge of the throughflow opening and the edge of the end wall of the container (which results in the drinking opening having to take a relatively small form). A further drawback is that the edge all around the throughflow opening is exposed, and contaminants can accumulate at positions where the user tends to place his or her mouth. It is further of great importance that the closure of the container is resistant to high pressures in the container, for instance when the container is used for the purpose of storing carbonated liquids.

It is the object of the present invention to provide an improved closing unit for a (wall of a) container and/or a wall of a container, wherein at least one of the above stated drawbacks and/or other drawbacks of the prior art is obviated or at least partially reduced.

It is also an object of the invention to provide a closing unit with a simple and/or compact construction and/or to provide a closing unit able to withstand higher pressures, for instance at least 2.1 atm or higher.

According to a first aspect of the present invention, a closing unit for closing a

throughflow opening provided in a wall of a container, particularly a beverage container such as a can, is provided, the closing unit comprising:

- an inner closing element which is configured to be mounted on the edge of the wall all around the throughflow opening provided therein, wherein the inner closing element is further configured to connect in mounted position against at least the inner side of the wall and is provided with a passage for the content of the container;

- an outer closing element which is configured to be coupled releasably to the inner closing element for the purpose of closing the passage provided therein;

wherein both the inner closing element and the outer closing element comprise a screw thread coupling for screwing the outer closing element onto the lower closing element;

wherein the outer closing element comprises a peripheral press-on edge which is embodied to clamp the outer closing element against the outer side of the wall of the container when screwing.

The closing unit can be configured to improve the closure of the throughflow opening provided by the closing unit. This is realized not only by coupling the outer closing element essentially liquid-tightly to the inner closing element and the first closing element to the container, but also by having said peripheral press-on edge press onto the container. As a result of the screwing, the axial distance between the cap of the outer closing element on the one hand and the upper side of the container wall on the other decreases, as a result of which the underside of the press-on edge is pressed against the upper side of the end wall of the container and is clamped fixedly thereagainst. The end wall can further take a somewhat flexible form (for instance in the case of a "can" or similar container) in order to further improve the clamping and, with this, the closure between the closing unit and the container wall.

The closing unit produces an improved closing of the container as a result of the presence of this extra closure (i.e. the extra closure, provided by the press-on edge, in addition to the closure by the cylindrical parts with screw thread coupling). The area inside the space enclosed by the peripheral press-on edge (this area also comprising the edge of the drinking opening) can hereby further remain clean more effectively (for instance during transport of the container) so that the user runs a smaller risk of placing his or her mouth on a contaminated part of the container.

By screwing the outer closing element on with force, the press-on edge is pressed firmly against the upper side of the end wall so that the press-on edge ensures an additional closure. The peripheral press-on edge is preferably embodied such that it protrudes radially relative to the peripheral edge of the cylindrical part of the outer closing element. By protruding radially at some distance from the periphery of this cylindrical part the press-on edge can be pushed directly onto the material of the container wall so that the peripheral press-on edge can function as additional closure of the throughflow opening of the container. Even if liquid were to seep out via the connection of the first and second closing element to the container wall (for instance in the case of extremely high pressure), the press-on edge can still stop this liquid. The press-on edge further ensures that the area surrounding the throughflow opening (i.e. the area where the mouth of the user touches the container) can generally be kept clean more effectively, which can result in increased hygiene.

With the latter in mind, in a further embodiment, in which the outer closing element comprises a cylindrical outer component with screw thread and the inner closing element comprises a cylindrical inner component with screw thread and wherein the outer component can be screwed into the inner component for the purpose of forming a first closure of the container, the outer closing element can comprise a cap provided with the peripheral press-on edge for the purpose of forming a second closure of the container. The cap can here be embodied such that, in screwed position, it clamps fixedly onto the upper side of the wall of the container and forms a covering of the inner and outer closing element. The cap can for instance be embodied to cover in screwed position the peripheral edge of the wall all around the throughflow opening.

As stated above, in determined embodiments both the outer and the inner closing element can comprise cylindrical (more particularly annular) parts with screw thread. The two parts can be mutually coupled by screwing the parts fixedly onto each other so that the cylindrical part of the outer closing element will move in axial direction (during use toward the wall of the container) so as to thus move the press-on edge thereof toward the wall. The screw thread coupling is preferably a conical screw thread coupling (preferably multi- thread), and the screw thread coupling is still more preferably a screw thread coupling as described in the patent publication WO 2015/041528 Al, the content of which must be deemed as incorporated herein.

In an embodiment the closing unit is embodied to snap fixedly onto the peripheral edge of the throughflow opening of the wall of the container. This peripheral edge can be embodied as an upright peripheral edge all around the throughflow opening, wherein the upright peripheral edge preferably extends at least partly obliquely relative to the remaining part of the wall and/or has a partially convex form in cross-section. Such a form enables a reliable snap-on connection, wherein the risk of the closing unit coming undone is minimal.

In a further embodiment the outer and/or inner closing element is manufactured from two or more components, wherein a first component is a plastic with relatively little elasticity and a second component is a relatively elastic plastic. The elastic component is preferably applied precisely at those positions where direct contact with the container takes place and where a good closure onto the material of the container is desired.

In a further embodiment the outer closing element comprises a support part and a pull- twist element, for instance a twist tongue. The pull-twist element can here be pivotally connected to the support part via a linear hinge element. The hinge element preferably extends through the rotation point of the support part so that the pull -twist element can function well as a grip with which the outer closing element can be screwed onto (or unscrewed from) the rest of the closing unit.

The pull-twist element can here take a form for pivoting between a lying starting position in which it extends substantially parallel to the upper surface of the support part and an upright operating position in which it extends at an angle relative to the upper surface. Compact dimensions can thus be achieved during transport, while the pull-twist element can still exert maximum torque during use in order to open the closing unit.

In further embodiments the screw thread takes a multi-thread form in order to couple or uncouple the closing elements over essentially the whole periphery with a rotation of the closing elements relative to each other over an angle of less than 180 degrees, preferably less than 90 degrees, still more preferably less than 50 degrees.

The screw thread coupling preferably takes a self-braking form. The screw thread coupling is further preferably embodied so that, essentially irrespective of the magnitude of the axial force exerted on the closing element, the closing element will not unscrew of its own accord.

According to another aspect, a wall is provided for a container, particularly a beverage container such as a can, wherein the wall has a throughflow opening and is further embodied for mounting of the closing unit described herein. According to yet another aspect a container is provided, particularly a beverage container such as a can, wherein the container has a wall with a throughflow opening for beverage and is further embodied for mounting of the closing unit described herein.

The invention will be elucidated on the basis of the following description of several embodiments thereof. Reference is made in the description to the accompanying figures, in which:

Figure 1 is a perspective view of a container, the throughflow opening of which is provided with a first embodiment of the closing unit;

Figures 2 and 3 are perspective top views of an outer closing element of a first embodiment of a closing unit, with the pull-twist element in respectively a folded-down and folded-open position;

Figure 4 is a perspective bottom view of the outer closing element of the first embodiment of the closing unit;

Figure 5 is a perspective view of the inner closing element of the first embodiment of the closing unit;

Figure 6 is a perspective view of the end wall of a container;

Figure 7 is an exploded perspective view of the end wall of figure 6 and the inner closing element of figure 5;

Figure 8 is a side view of the end wall of figure 6 and the inner closing element of figure 5; Figure 9 is a side view of the outer closing element according to the first embodiment of the closing unit;

Figure 10 is a partially cut-away view of the end wall;

Figure 11 is a perspective exploded view of a first and outer closing element of the first embodiment, and of an end wall;

Figure 12 is a cross-section of the outer closing element according to the first embodiment; Figures 13-21 are views and cross-sections of a second embodiment of the closing unit;

Figure 22-26 are views, optionally partially in cross-section, of a further embodiment of the closing unit and the container.

Figure 1 shows a view of a container 1 , for instance a cylindrical beverage can for containing beverage, wherein the upper end wall 2 is provided with a closing unit 3 according to an embodiment of the invention. Closing unit 3 comprises an inner closing element 4 (shown in figures 5-8, 11, 12) and an outer closing element 5 (shown in figures 2-4, 9, 11, 12). Inner closing element 4 comprises a lower ring 14 which is embodied such that it can be mounted on the end wall 2 of the container, while outer closing element 5 comprises a cap 15 which is embodied such that it can be mounted releasably on inner closing element 4.

Cap 15 comprises an upper ring 13, a double -layer support part 16 extending parallel to end wall 2 of container 1 , a single -layer pull-twist element 18 (also referred to here as the twist tongue) which is embodied for pivoting relative to this support part via a hinge 17, and a single- layer support part 32 (preferably formed integrally with the lower layer of the double -layer support part 16), as shown in more detail in figures 2 and 3. Support parts 16 and 32 close the cap on the upper side, while pull-twist element 18 is used to enable the cap to be twisted open and closed. In figure 2 closing unit 3 is shown in a lying position of pull-twist element 18 and in figure 3 the closing unit is shown in an upright position (i.e. the operating position) with a pull-twist element 18 pivoted upward.

In the shown embodiment pull-twist element 18 has essentially the shape of a semicircle, wherein the flat edge of the semicircle is formed by the (linear) hinge 17. The hinge is positioned such that it extends through the rotation point of cap 15. Pull-twist element 18 can be easily pivoted upward by a user (wherein grip 21 facilitates engagement by the user) from the lying position shown in figure 2 to the upright position shown in figure 3). A user who has taken hold of upright pull-twist element 18 can now as a result of said position of the hinge easily twist cap 15 to the left or to the right (direction 9, rotation about an imaginary axis 8 in axial direction) in order to twist the cap of the closing unit open or closed.

Cap 15 further comprises two upright edges 22 with a slightly conical form, which ensure that when pull-twist element 18 is pressed back into the original, closed position, peripheral edge 24 of pull-twist element 18 "snaps" under these edges so that the pull-twist element tends to remain in the lying position. Referring to figures 2 and 3, closing unit 3 also comprises an anti-tamper provision. In the shown embodiment the anti-tamper provision comprises an anti-tamper pin 23 which is formed on upper ring 13 and can be slid into anti-tamper opening 28. This pin 23 has a length such that when a pull-twist element 18 is in lying position, it still protrudes slightly above the upper surface of pull-twist element 18. Pin 23 is further preferably manufactured from plastic so that the upper plastic outer end can be fused (for instance by means of spot welding) with the plastic of the rest of pull-twist element 18. The fused pin forms a sealed whole together with the pull-twist element 18, wherein the seal is visibly and tangibly broken during opening, i.e. pivoting upward of pull-twist element 18, so that the cap can be unscrewed.

Cap 15 further comprises a blocking element in the form of a pin 26 which has the function of preventing cap 15 from being unscrewed without breaking the above stated anti-tamper provision (seal). When the pull-twist element 18 is folded down, pin 26 passes through a corresponding opening 27 in upper ring 13 and then falls into a crescent-shaped recess 28 in lower ring 14 (figure 5) arranged for this purpose. This prevents rotation of cap 15 relative to lower ring 14 in lying position of pull-twist element 18.

As shown in more detail in figure 4, the cap 15 of outer closing element 5 comprises a mounting part 19 provided on the underside. In the shown embodiment mounting part 19 comprises a substantially cylindrical wall which is provided on the outward directed radial side surface with an external screw thread 20. In similar manner, and as shown in more detail in figure 5, the lower ring 14 of inner closing element 4 comprises a mounting part which comprises a substantially cylindrical wall 39. Cylindrical wall 39 is provided on the inward directed radial side surface with internal screw thread 25. This screw thread 25 can engage on screw thread 20 of the mounting part 19 of cap 15.

As shown in figure 4, the lower annular outer end 30 of mounting part 19 comprises an outer surface which takes a smooth form and which lies against the sealing surface 44 on the underside of lower ring 14 in closed position of cap 15 so that a good sealing is obtained between the two closing elements 4 and 5. Sealing surface 44 can be provided with an annular sealing element (seal) 45 (figure 8). The sealing element can comprise a relatively soft material, such as a thermoplastic elastomer (TPE) or a material with similar properties. The sealing element ensures an excellent sealing relative to the smooth lower annular outer end 30 of mounting element 19 of cap 15.

Such a good sealing between cap 15 and lower ring 14 is particularly important when the container is intended for storing a carbonated liquid and the pressure can rise high inside the container. For the purpose of a good sealing, strengthening ribs 33 are further arranged on the inward directed radial side surface of cylindrical part 19. These strengthening ribs ensure that the form of the cap is retained when the pressure in container 1 rises. These strengthening ribs also ensure a correct degree of stability of the cylindrical wall when the pressure in the hollow space (which in closed position is in connection with the content of the container) partially enclosed by the cylindrical wall increases and the cylindrical wall (manufactured from elastic material) has a tendency to move radially outward under the influence of the pressure in the container so as to thus increase the clamping force between the outer and inner closing element and, with this, improve the measure of closure.

Provided on the underside of upper ring 13 of cap 15 is a peripheral press-on edge 31. In the shown embodiment press-on edge 31 is formed by a cylindrical, axially extending flange. This flange is concentric relative to the cylindrical wall of mounting part 19. Press-on edge 31 is embodied such that during use, when the closing unit is closed, it surrounds mounting part 19 and can press with underside 34 against the upper side of end wall 2 and so can provide protection against external influences (i.e. influences from outside, such as dirt, and/or influences from inside, for instance content of the container seeping through the seal of the closing unit).

The embodiment of lower ring 14 shown in figure 5 can be mounted on the end wall 2 of container 1 shown in figure 1 and, in more detail, in figures 6, 7, 8 and 10. The figures show that lower ring 14 can be pressed from below against the edge around the drinking opening in end wall 2 of container 1 and in this position can be snapped fixedly onto the container. A sealing ring 40 of soft (for instance elastic) sealing material is arranged on top of the relatively hard plastic material of radial flange 43 of lower ring 14 (figure 5). In mounted position this sealing material lies against the underside of end wall 2 and contributes to a good (airtight) closure between lower ring 14 and end wall 2. The sealing material can for instance be a thermoplastic elastomer (TPE) or a material with similar properties. In order to mount lower ring 14 on the end wall the lower ring is provided with an annular mounting edge 41, also referred to here as the snap edge or click edge, since this edge enables the lower ring to be snapped fixedly onto the container. End wall 2 (which can for instance be made of aluminium) of the container can be embodied for this purpose with an annular conical edge 50 all around throughflow opening 6, as is shown in figures 6-8 and 10. Conical edge 50 is further provided with one or more upright protrusions 51. The special conical form of edge 50 enables plastic lower ring 14 to be pressed into the throughflow opening 6 of aluminium end wall 2 by means of a pressing mechanism (for instance a press) so as to thus realize a strong connection, which will no longer detach, between lower ring 14 and container 1.

Lower ring 14 is further provided with a number of recesses 42 in which the above stated upright protrusions 51 of end wall 2 fit in order to counteract co-rotation of lower ring 14 when cap 15 is twisted open and closed. Figure 5 also shows the above stated recesses 28 in the lower ring in which the anti-rotation pin 26 locks when the pull-twist element is folded down so as to thus prevent twisting open without breaking the seal.

Figure 8 shows a side view of the (aluminium) end wall 2 of container 1 and the (plastic) lower ring 14. The figure also shows the snap/click edge 41 into which the conical upright edge 50 of end wall 2 falls. Also shown in the figure is the position of soft sealing ring 40 on flange 43 for ensuring sealing at the surface of container 1 , and of the soft sealing ring 45 on surface 44 for ensuring a good sealing of cap 15 when the cap is screwed into the lower ring.

Figure 9 shows a side view of cap 15 with the pull-twist element 18 in lying position, i.e. flush with the upper side of the cap. The figure further shows the anti-tamper provision in the form of pin 23, which protrudes above the plastic surface of pull-twist element 18 and can be fused with the pull-twist element and so serve as a seal.

Figures 11 and 12 show the relative positions of the first and outer closing element and the position of all components, while figure 12 shows a cross-section of closing unit 3 together with an end wall. The figure shows, among other things, the special (self -braking) screw thread 20, sealing edge 30 which ensures the closure at the soft seal on the underside of lower ring 14, strengthening ribs 33 on the inner side of the cap, which serve to retain the form of the cap in the case of high pressure, the edge 31 of the cap, which (in closed position of the closing unit) has a close fit with and connection to end wall 2 in respect of possible accumulation of moisture during and after a pasteurization process which may be performed on the container.

Closing units according to embodiments of the invention can be simplified relative to the closure as described in WO 2015/041528 Al, for instance by using fewer elements and applying less material, lower heights and simpler production and assembly methods. The number of (plastic) closing elements can be reduced to two (i.e. an outer and an inner closing element 4, 5). The closing unit can comprise a lower ring with a soft seal (for instance a TPE seal) on the upper side and a soft seal (for instance a TPE seal) on the underside.

The closing unit is preferably provided with the conical screw thread coupling as described in WO 2015/041528 Al, the content of which must be deemed as incorporated herein.

Referring to figures 13-21, a further embodiment of a closing unit is described. In so far as this is not specifically stated, the further embodiment of the closing unit corresponds to the above described first embodiment and a detailed description of the further embodiment is therefore dispensed with here.

Lower ring 54 (figures 13, 14) can be attached to end wall 2 in one way, for instance by snapping/pressing the lower ring into the end wall in the cavities arranged for this purpose. Once the lower ring has been snapped fixedly into position it can in principle no longer be pressed back out of the cover (i.e. the wall of the container) as a result of the conical form of the upright edge (which has a yielding capacity but can spring back) which is pressed into the peripheral area all around the throughflow opening 6 in end wall 2 of container 1. The two upright aluminium protrusions 51 on this conical edge 50 fall into the arranged opening(s) 60 in lower ring 54 and ensure that the lower ring cannot co-rotate in the aluminium cover.

Recesses 61 on the upper side of the lower ring are arranged as "blocking member" of the tamper evidence (seal). The seal on the upper side of the lower ring ensures the sealing of liquid between lower ring and end wall. The wall thicknesses and thus the quantity of material (weight) may have decreased.

Cap 80 for opening and closing the throughflow opening (i.e. the drinking hole) has on one side a double plastic layer, which can be moved/pushed upward in simple manner by means of the "grip" portion because a pivot point is arranged in the centre of cap 80. This pushed-up "tongue" thus forms the firm grip for unscrewing the cap with a short stroke (45 degrees). The cap thus has an option for having for instance promotional codes concealed under the pull-twist element (twist tongue) which has been placed in flat position.

Arranged on the lower surface of cap 80 are two lips 81 which secure the flat position of the pull-twist element (twist tongue) by means of a snap connection. The cap is provided on the underside with an additional peripheral edge, which has two functions. The edge ensures an extra sealing of the content of the container relative to the outside world and ensures that the edge of the end wall all around the throughflow opening remains clean. This peripheral edge moreover ensures extra pulling force (screw/nut principle) when screwing on the cap, so that the inner closing element is additionally pressed against the aluminium cover and the seal between the inner closing element and the container is thereby improved. Cap 80 is provided with the unique conical screw thread complementary to the lower ring, and the tamper evident provision is also positioned on the inner side of the upright edge. A small pawl which is positioned at a determined angle is "entrained" in the rotation direction when the cap is screwed on. Upon twisting open, this pawl will fall into the arranged blocking member of the lower ring and thus become blocked, and upon continued twisting the pawl will be pressed outward and thus in this way visibly break the thin, injection-moulded plastic seal. This occurs only once, only in a can which has not been opened before. Arranged on the inner side of the cap are "ribs" for strengthening and for counteracting deformation in the case of high pressure. Situated on the underside of the conical screw thread is the smooth portion which is pressed into the soft seal when the cap is tightened and thus forms the seal.

If desired, the closing unit can be easily modified in respect of the size of the drinking opening (drinking hole). The position of the drinking hole is also flexible, although it may be assumed that it has to be positioned as close as possible to the folded edge of the cover in order to maximize the drinking comfort.

In order to provide consumers with instructions for use, i.e. opening and closing of the cap, an "arrow" is embossed into the aluminium indicating the rotation direction for opening the cap, this embossed form also being applied to impart some strength to the aluminium surface. A text reading "lift" is additionally applied to the upper side of the plastic cap, making it clear that the tongue should first be pulled upward, in effect the same movement which is presently also the case in the current cans. As soon as the pull/twist tongue is in the upright position, a text indicating the twisting direction for opening the cap has also been applied to the second plastic layer.

Since the closing unit has a separate cap 80 which is not connected to the other plastic elements, this provides an advantage in waste separation because the cap can be disposed of separately of the can, for instance in the waste bin for plastic.

The figures show that the (aluminium) cover can be provided with a conical upright edge with two "tabs", which are intended for placing in the cavity in the lower ring in order to counteract co-rotation of the plastic element when the cap is tightened. The conical upright edge functions as a "spring" for "snapping" the lower ring into the aluminium cover, which cover cannot be pressed back out due to the form. The plastic lower ring is provided with a special recess into which the lower ring snaps, the lower ring being provided on the upper side with a soft sealing (seal) which ensures the closure against the underside of the aluminium can. Also present on the underside of the lower ring is a soft seal which ensures the sealing of the cap. The cap and the lower ring are both provided with the special conical screw thread which ensures a firm

connection. The cap is provided with an additional edge with the function of generating extra pulling force, so that the cover is clamped firmly between the two plastic elements. This edge also has the function of screening the whole drinking portion from dirt and the like. Referring to figures 2 and 3, in determined embodiments the cap can be provided on the upper side with a double layer which can be pushed upward by means of a hinge and in this way forms the grip for screwing and unscrewing the cap. Arranged on the lower layer are two lips which serve to hold the folded-down pull-twist element (twist tongue) snapped fixedly in the flat position.

Referring to the figures, for instance figures 15 and 17, the tamper evidence 72 (seal) can be positioned on the inner side and on the edge of the cap. Arranged on the inner side of the upright edge of the cap at an oblique angle is a pawl 70, which has an "entraining" function when the cap is twisted shut and has a "blocking" function when the cap is twisted open, as soon as the pawl reaches the notch arranged for this purpose. Because the pawl comes to lie at a right angle, the pawl will yield toward the outer side during continued twisting of the cap, and visibly break/tear the thinner plastic edge herein. This happens once only, when the cap is opened for the first time.

The form of the closing unit makes it possible to realize diverse sizes of drinking hole openings, such as small, medium and big size. Because the "snap" lower ring is applied, the plastic lower ring element has a narrow edge, which in turn has a positive effect on the position of the drinking opening, which has to be positioned as close as possible to the folded edge of the can lid for drinking comfort.

Figures 22-26 show a further embodiment of the closing unit. In so far as it is not stated otherwise, this embodiment corresponds to the above described embodiments and a detailed description can therefore be dispensed with. The further embodiment is distinguished by the alternative manner in which the lower ring is prevented from co-rotating when cap 15 is twisted open and closed. Figures 24 and 25 show a different lower ring 84 which can be pressed from below against the edge around the drinking opening in end wall 82 (figure 23) of the container and can be snapped fixedly onto the container in this position. End wall 82 (which can for instance be made of aluminium) of the container is embodied with an annular conical edge 85 all around the throughflow opening 86, as shown in figure 26. The special conical form of edge 85 enables plastic lower ring 84 to be pressed into throughflow opening 86 of aluminium end wall 82 by means of a pressing mechanism so as to thus realize a firm connection (particularly a click-snap-connection), which will no longer detach, between lower ring 84 and the container.

In contrast to the above described conical edge 50, conical edge 85 is not provided with one or more upright preformed (aluminium) surfaces or protrusions 51. In order to ensure that lower ring 84 does not co-rotate, or does not co-rotate too much, when the cap is opened or closed, use is made of the preformed engaging edge 90 in cover 82 in combination with one or more radial protrusions 91 on the peripheral edge 92 of lower ring 84. Engaging edge 90 is substantially annular and comprises a radially inward directed upright surface 96. This upright surface 96 is an engaging surface for the radial protrusions 91 of lower ring 84. As shown clearly in the bottom view of figure 22, throughflow opening 86 (against the peripheral edge of which the closing unit is mounted) is provided outside the centre of engaging edge 90 of the cover of the container. This means that lower ring 84 is also placed outside the centre (i.e. the centre of the lower ring does not coincide with the centre of engaging edge 90). If lower ring 84 were to have a tendency to rotate during opening or closing of cap 15, the radial protrusions come to lie on upright surface 96 of the engaging edge 90 of the cover of the container. This prevents lower ring 84 from co-rotating. In an alternative embodiment the radial protrusions take a larger form, for instance over the whole surface. Co-rotation of lower ring 84 is likewise counteracted in this embodiment.

An advantage of the further embodiment shown in figures 22-26 is that the strength in the upright aluminium edge 85 can be guaranteed more effectively on/or tearing of the corners in (aluminium) cover 82 can be counteracted.

The invention is not limited to the embodiments thereof described herein. Numerous adjustments, modifications and additions can be envisaged, all falling within the scope of the following claims.