BOX WITH SNAP-ON CLOSURE

Abstract

A closure system with a three-dimensional structure with an opening and a lid for plugging onto the three-dimensional structure in order to close the opening. The lid is bistably deformable between a first state, in which its end wall is curved in the plug-in direction, and a second state, in which the end wall is curved against the plug-in direction. An annular edge section of the lid has a greater outer circumference in the first bistable state than in the second bistable state and forms a clamping fixture of the lid to a wall region of the opening when the edge section is pressed inwards in the first state or outwards against the wall region in the second state. The three-dimensional structure transfers a force from the outside at specified locations that to a snapping process of the lid from one to the other bistable state.

Description

[0001] Snap-on closures are characterized in that they can snap in a bistable manner between an open state and a closed state. They generally consist of a disc-shaped top wall which is deformable in a bistable manner between a concave first state and a convex second state, and an annular edge portion. The outer periphery of the annular edge portion decreases upon transition of the top wall from the first state to the second state.

[0002] Such snap-on closures used to be made of metal only and were marketed by Hoffmann Neopac as merchandising products under the brands Klick-Klack.RTM. and Klipp-Klapp.RTM.. In patent documents DE 10 2015 103 036 B4 and WO 2017/076398 A1 it is described how such snap-on closures can now also be made of plastics. The most important aspect for the functioning of the snap mechanism is the transfer of the bistable deformation of the top wall to the adjacent annular edge portion. Only if the flipping-over movement between the convex and the concave curvature of the top wall transfers its deformation stress to the edge portion, this allows for a widening of the edge portion and a corresponding enlargement of the outer circumference of the closure cap, which then also allows for opening the container covered by the cap. Here it is of central importance that the angle included at the transition between the top wall and the edge portion remains the same for both bistable states, i.e. that the closure cap material at this transition region is stiff enough to transfer the deformation stress of the top wall completely to the edge portion.

[0003] In addition, the edge portion itself should be sufficiently flexible to allow its outer periphery to widen in the first bistable state of the top wall which is curved in the direction of attachment. According to DE 10 2015 103 036 B4, this is achieved, for example, by the fact that folds are formed at the edge portion which unfold in the first state and thus allow the outer circumference to be enlarged. Then the entire cover can be made of a single plastic material with homogeneous density or elasticity. Preferably, however, the edge portion obtains the necessary elasticity by forming at least one expansion portion in the edge portion of the cover from a softer material component than the remaining edge portion (see WO 2017/076398 A1). The expansion portion expands elastically under stress and allows the edge portion to expand into a concave curvature state, while the base material of the cover is otherwise stiff enough to maintain a constant angle in the transition region between the top wall and the edge portion. This allows the cover to be folded over into the bistable state with the larger outer circumference.

[0004] The expansion portion is preferably manufactured in one piece together with the rest of the cover using a multi-component injection molding process. A second material component is injected for the expansion portion. The second material component is softer and/or more elastic than the first material component used for the rest of the cover. In order to further support the constant angle in the transition region between the top wall and the edge portion, the cover in this transition region may also preferably have a higher material thickness of the harder (base) material component than in the main region of the top wall or be injected by use of an even harder third material component. This yields the particular advantage that the overall thickness of the cover material may remain constant. A homogeneous thickness is not only visually appealing, but also reduces the number of steps and edges in which dirt can accumulate.

[0005] A design in which a latching ring made of the softer second material component is molded onto the entire inner and/or outer circumference of the edge portion is particularly preferred. This latching ring can seal a groove or a step in the side wall of the opening to be closed, so that even a sealing closure of the opening is possible.

[0006] There is still room for improvement in the presently available plastic snap-on closures with regard to the user's operation of the flipping-over process. Until now, it has been mandatory to press or pull up the cover with a certain minimum force at its edge portion or at a handle member formed on its top wall in order to allow the top wall to snap from one bistable state to the other. This has the disadvantage that the areas on which the user is to exert his force must always be sufficiently exposed in order to reach the desired pressure points with the fingers. This, in turn, undesirably restricts the design possibilities for the overall closure system consisting of container and cover. On the other hand, it would be desirable to reduce the minimum force required for the snap-action process if the user applies the force at precisely predefined pressure points. It would also be advantageous if none of the snap-action states would be exclusively operable by a pulling force, because then there would no longer be any necessity to provide a (two-hand-operated) handle member on the cover.

[0007] Accordingly, the object of the present invention is to provide, in a closure system consisting of a three-dimensional structure with the opening to be closed and a cover which snaps between two states in a bistable manner, more possibilities for the user to trigger the snap-over process and, preferably, to reduce the minimum force required for the triggering operation. In particular, a closure system is desirable in which both bistable states can be triggered by manual pressing, so that both snap-open processes can be operated without a handle member and usually with just one hand.

[0008] At least a partial solution to the above-mentioned problem is achieved by the features of present claim 1. The subclaims relate to preferred embodiments.

[0009] In accordance with the present invention, the three-dimensional structure, in particular a container or a tubing end which is open on at least one side, is configured in such a way that a force acting on the closure system from outside at at least one predefined location is transferred to the edge portion of the cover in such a way that the cover is snapped from one bistable state to the other.

[0010] In the case of a lid clamping from inside against an opening wall, the opening wall of the three-dimensional structure is preferably flexible at least at the predefined location in such a way that, by elastic deformation, a force acting on the opening wall at least on one side, and preferably on both sides, transversely to the direction of attachment is transmitted to the edge portion of the lid. This allows the lid to lie completely within the opening to be closed without the need for the user to provide a handle member on the top wall of the lid to trigger the snap-over process into the open position. In a particularly preferable embodiment, the point of the opening wall which is, opposite to the direction of attachment, most remote projects by a certain amount of projection from the location at which the edge portion of the lid presses from the inside against the wall region. A force acting transversely to the direction of attachment on this outer wall region can then trigger the snapping-over of the cover with less effort, because the protrusion acts as a lever arm.

[0011] According to another preferred embodiment, the cover clamps as a cap from the outside around the wall region of the opening to be closed. The geometric design of the wall region of the opening at the outermost end region in the direction opposite to the direction of attachment allows the cap to contact this end region with an area of the top wall that is a little offset from the edge portion towards the center of the cap. This allows the cap to be brought into its closed position not only by a force acting transversely to the direction of attachment on the edge portion, but also by a force exerted in the direction of attachment, provided that this force is exerted on a pressure point which is radially further outwards than the contact point of the opening wall with the top wall. The distance between the contact-point and the pressure-point here again works as lever arm and reduces the required operating force correspondingly.

[0012] In this description, the closure element of the opening to be closed is generally referred to as a cover. If the cover clamps on the outside of the opening wall, the cover is called a cap; if the cover clamps on the inside against the opening wall, it is called a lid.

[0013] In the following, the invention is explained in greater detail using several embodiments. Therein shows:

[0014] FIG. 1a a side view of a closure cap partially shown in section according to a first embodiment of the invention;

[0015] FIG. 1b a top view of the cap of FIG. 1a;

[0016] FIG. 1c an enlarged detailed view in a section A-A in FIG. 1a;

[0017] FIG. 1d an enlarged view of a detail X of FIG. 1a;

[0018] FIG. 1e an enlarged detailed view in a section C-C in FIG. 1c;

[0019] FIG. 1f an enlarged detailed view in a section B-B in FIG. 1c, in which at the same time the closure principle of a container with the cap is shown;

[0020] FIG. 2a a cross-sectional view of a closure system of the present invention with the closure cap according to the first embodiment in the open position;

[0021] FIG. 2b a cross-sectional view of the closure system of FIG. 2a in the closed position;

[0022] FIG. 2c an enlarged detail of FIG. 2a in a first modification of the first embodiment in the open position;

[0023] FIG. 2d the enlarged detail of FIG. 2a in a second modification of the first embodiment in the open position;

[0024] FIG. 2e the enlarged detail of FIG. 2a in a third modification of the first embodiment in the open position;

[0025] FIG. 3a a cross-sectional view of a closure system of the present invention with a closure lid according to a second embodiment in the open position;

[0026] FIG. 3b a cross-sectional view of the closure system of FIG. 3a in the closed position;

[0027] FIG. 3c an enlarged detail of FIG. 3b;

[0028] FIG. 3d the enlarged detail of FIG. 3c in a first modification of the second embodiment in the closed position;

[0029] FIG. 3e the enlarged detail of FIG. 3c in a second modification of the second embodiment in the closed position; and

[0030] FIG. 3f the enlarged detail of FIG. 3c in a third modification of the second embodiment in the closed position.

[0031] In the first embodiment shown in FIGS. 1a-f, the cover is designed as a cap 20, which is to embrace a container wall 12a from the outside. The FIGS. 1a to 1f all show the cap 20 in its convex and outwardly curved snap position (i.e. curved in the direction opposite to the direction of attachment). This is the shape the cap takes in its locking position. FIG. 1f also shows how it is possible to snap into the opening wall 12a to be closed in this position, but this will be explained in greater detail later referring to FIGS. 2a to 2e.

[0032] The cap 20 shown in FIGS. 1a-f has a top wall 21 which is essentially circular in shape, with a ring-shaped edge portion 22 formed on its outer periphery. FIG. 1a shows a side view partially shown in section. In the left part of the Figure the cap 20 can be seen from the side, while the right part is cut inside so that the back inside of the cap 20 can be seen. In the Figures, the uncut soft component (second material component) is always dotted and the cut soft component is crosshatched, while the cut hard component (first material component) is simply hatched.

[0033] If the top wall 21 snaps into its concave and downwardly (i.e. in the direction of attachment) curved state, the outer circumference of the edge portion 22 increases. In order to keep the angle .mu., which is included by the top wall 21 and the edge portion 22 in their transition region, constant in the two bistable states, the cap material should have sufficient rigidity. According to the invention, this is achieved by the fact that the transition region between the top wall 21 and the edge portion 22 has, at least in partial regions, but preferably over the entire circumference, a higher material thickness than the central region of the top wall 21. As shown in FIGS. 1e and 1f, the material gets thicker upwards, i.e. in the direction opposite to the direction of attachment, so that the transition region between the top wall 21 and the edge portion 22 runs smoothly on the inside. Alternatively, the material thickenings can also extend downwards and lead to a correspondingly contoured inner wall surface of the lid.

[0034] The outer circumference in the concave bistable state (explained later on referring to FIG. 2a) is enlarged as compared to the convex state shown in FIGS. 1e, 1f and 2b. This enlargement requires a sufficient stretching flexibility of the circumferential edge portion 22 to enable the increased outer circumference in the concave bistable state. According to the present invention, this is achieved by circumferentially (preferably equidistantly) arranged expansion portions 24 made of the softer second material component, which alternate--as can be seen particularly well in FIGS. 1a and 1d--with intermediate portions 23 made of the harder first material component. As shown in FIG. 1b, the expansion portions 24 start from the transition region between top wall 21 and edge portion 22 and then widen towards the radial outer edge. The softer material of the expansion portions 24 ensures that the edge portion 22 can enlarge at its outer circumference when being in the concave (i.e. open) snapping position of the cap 20. The expansion portions 24 would then no longer have the constant width shown in FIGS. 1a and 1 d, but would widen radially outwards.

[0035] The edge portion 22 terminates in its expansion portions 24 as well as in its intermediate portions 23 in a latching ring 29 which is provided at the inner circumference and which is also formed from a softer material component, preferably the same as the expansion portions 24. This inner circumferential latching ring 29 imparts additional dimensional stability to the thin-walled cap 20, but is also sufficiently elastic to enable the enlargement of the outer circumference in the convex foldover position shown in FIG. 2a. Due to its softer material properties, the latching ring 29 can work as a sealing ring.

[0036] The latching ring 29 is formed on a lip portion 23a, 24a of the edge portion 22, the lip portion projecting radially inwards by 90.degree.. The reason for this is that the cap 20 should grip the opening 11a to be closed from the outside, as will be explained in greater detail in FIG. 1f and, in particular, in FIGS. 2a-e. The lip portion 24a adjacent to the expansion portion 24 is made of the softer second material component, while the lip portion 23a adjacent to the intermediate portion 23 is made of the harder first material component. However, the lip portions 23a and 24a can also be entirely formed from the softer second material component. In this case, the entire radial inner part of the edge portion 22 would belong to the latching ring 29 or the lip portion would be omitted.

[0037] As a manufacturing process for the cap 20, the above-mentioned multi-component injection molding using one or more thermoplastics is particularly suitable. The multi-component technique allows a first (base) component to be injected for the top wall 21 and the intermediate portions 23, while the expansion portions 24, as well as the latching ring 29, are directly injected from a softer second component in a single manufacturing process. The optional third (particularly hard) material component for the transition region between the top wall and the edge portion can also be injection-molded directly in a single multicomponent injection molding process.

[0038] Preferred materials for the first component are: thermoplastic elastomers (TPE) and thermoplastic urethane (TPU).

[0039] Preferred materials for the second component are: Polycarbonate (PC), Acrylonitrile Butadiene Styrene (ABS) and Polystyrene (PS).

[0040] Preferred materials for the third component are: glass fiber reinforced polyamide (PA) or other glass fiber reinforced plastics.

[0041] Instead of producing the cover entirely by injection molding, it is also possible to overmold a blank obtained previously in a separate manufacturing step. It is conceivable, for example, that a cap which is made of sheet metal or a light metal (e.g. aluminum) and which essentially has the shape of a conventional Klick-Klack box cap with metal fingers at the outer periphery, could be encapsulated in the edge area with the softer (second) plastic component. The obtained result is a cover with significantly improved tightness against the leakage of liquids or gases from the box to be closed.

[0042] Instead of manufacturing the cap or lid from several material components of different hardness or elasticity, the cap or lid can also be manufactured by a thermoforming process, i.e. deep drawing, or by an injection molding process from only a single plastic material. Then, instead of the softer expansion portions at the edge portion, the above-mentioned folds are formed and reinforcement ribs and/or material thickenings are provided at the transition region between the top wall and the edge portion to keep the inner angle there constant in both bistable states.

[0043] FIGS. 2a-e show the functional principle of the cap 20 according to the first embodiment of the invention in a closure system consisting of the container 10a and the cap 20. The opening 11a to be closed has, in the shown wall region 12a, a circular groove 13a on the outer surface, at the lower end of which a step 15a is formed. The step is not necessary and can also be omitted. Above the groove 13a, the wall region 12a continues into a protrusion 14a, which has essentially the same height as the edge portion 22 of the cap 20.

[0044] FIG. 2a shows the cap 20 in its open, concave position, i.e. with the top wall 21 curved downwards. The inner diameter of the edge portion 22 is correspondingly larger. This inner diameter is larger than the outer diameter of the outer groove 13a, so that the cap 20 can be removed from the opening 11a in the open state shown in FIG. 2a.

[0045] In FIG. 2b, the top wall 21 has a convex curvature, i.e. it is curved upwards in the direction opposite to the direction of attachment. Then, the edge portion 22 with the inwardly projecting latching ring 29 only has an inner diameter which is smaller than the outer diameter of the groove 13a. Thus, the cap 20 is firmly engaged with the opening wall 12a to be closed and only snaps back into its first bistable state shown in FIG. 2a when a force F acts on the top wall 21 in the direction of attachment. Due to its elastic material properties, the ring 29 also works as a sealing ring to prevent gases or liquids from escaping through the opening 11a.

[0046] As can be seen particularly well in FIG. 2c, the end section 16 of the wall region 12a is tapered, i.e. the outer diameter of the opening 11a narrows in this end section 16, while the inner diameter of opening 11a remains constant. This provides a contact point A1 between the top wall 21 and the end section 16 which is offset towards the center of the cover 20 by a distance a1 from the transition region between the top wall 21 and the edge portion 22. If a force F.sub.2, which acts essentially in the direction of attachment, is exerted from above on the top wall 21 at a pressure point A2, this force F.sub.2 acts on the edge portion 22 via a lever arm of the length a1 and triggers the snap-over process. Until now, this was only possible by means of the force F.sub.0 acting directly on the edge portion 22 in FIGS. 2a, 2c and 2d from sideward, essentially transversely to the direction of attachment.

[0047] As also shown in FIG. 2c, an additional extension 18 may be attached or molded to edge portion 22 in accordance with an optional modification. This extension 18 makes it possible to reduce the force F.sub.0, acting essentially transversely to the direction of attachment and required to close the cap, to a lower value F.sub.1, because the user can exert his force via an extended lever arm when he compresses the cap 20 at the extension 18.

[0048] According to another modification shown in FIG. 2d, the lever arm a1 can be extended by providing a narrowing element 17 to the end section 16', which narrowing element can be attached to or integrally formed at the end section 16' and which also constricts the inner diameter of the wall region 12a, i.e. the opening 11a, in the area of the end section. Then a force F.sub.3 exerted on the pressure point A2 acts via the longer lever arm a2 with the contact point A1 as a lever point even more efficiently on the edge portion 22 and thus facilitates the release of the snapping-over process.

[0049] According to another modification shown in FIG. 2e, the lever arm a1 of FIG. 2c can also be extended by a top wall extension 19. In contrast to the extension 18 shown in FIG. 2c, the top wall extension 19 is not arranged at the edge portion 22 but at the top wall 21. This top wall extension 19 can be attached to or integrally molded with the top wall 21, in partial areas or across the entire circumference thereof. The top wall extension allows the force F.sub.2, which acts essentially in the direction of attachment and which is required to close the cap 20, to be reduced to a lower value F.sub.3'. When the user presses the cap 20 down at a pressure point A2 of the extension 19, an applied force F.sub.3' generates, due to the longer lever arm a2' with contact point A1 as the lever point, a greater torque than that generated by the force F.sub.2 via the lever arm a1 of FIG. 2c. Otherwise, the structure according to the modification shown in FIG. 2e corresponds to that of FIG. 2c. It goes without saying that the modifications shown in FIGS. 2c, 2d and/or 2e can also be used in combination.

[0050] FIGS. 3a to 3f show the functioning of another closure system according to the present invention. The system uses a lid 30 according to the second embodiment to close an opening 11a. The lid can be manufactured in the same way as previously described for the cap 20 and has expansion portions and intermediate portions in the edge portion 32 in the same way, whereby only the intermediate portions 33 are visible in the cross-sections of the Figures for the sake of clarity. Also, the lip portions and the modifications are possible with the lid 30 analogously to the cap 20.

[0051] The only difference to cap 20 is that the lid 30 does not have an inwardly protruding latching ring 29, but an outwardly protruding latching ring 39. This is because it is not intended to clamp to the container wall from the outside, but from the inside. Another conceivable option is, of course, a cover with both an inwardly and an outwardly projecting latching ring, which can then be used as both a cap and a cover. Furthermore, it would also be possible to place the lid 30 upside down on the box 10b without significantly changing its functionality. The middle section of the edge portion 32 would then not extend in the direction of attachment but also opposite thereto, and the cover 30 would change from its closed state to its open state by exerting a pressure on the top wall 31 in the direction of attachment, which can be advantageous for certain applications.

[0052] The edge portion 32 thus ends both in its expansion portions (not shown) and in its intermediate portions 33 in an outer circumferential latching ring 39. The latching ring is also formed from a softer material component, preferably the same material as the expansion portions. This circumferential latching ring 39 not only gives the thin-walled lid 30 additional dimensional stability, but is also sufficiently elastic to enable the enlargement of the outer circumference in the convex folding position shown in FIG. 3b. Due to its softer material composition, the latching ring 39 not only clamps particularly well in the inner groove 13b of the opening wall 12b to be closed, but can also provide the functionality of a sealing ring.

[0053] The wall region 12b of the opening 11a to be closed has a ring-shaped groove 13b inside, into which the lid 30 is to engage, and which forms a step-shaped shoulder 15b at its lower edge. The area of the wall region 12b above the groove 13b (i.e. against the direction of attachment) is referred to as the protrusion 14b.

[0054] If the lid 30 is inserted from above into the opening 11b, the edge portion 32 hits with its latching ring 39 against the step 15b. This tells the user that the axial end position of the cover 30 has been reached which is the end position intended for locking. If the user now presses the top wall 31 downwards by a force F acting vertically downwards, the top wall 31 snaps from its convex bistable state shown in FIG. 3a into its concave bistable state shown in FIG. 3b. Due to the stiffness of the cover material in the transition region between top wall 31 and edge portion 32, which (as explained above) is preferably supported by an increased material thickness, the angle .mu. remains constant during this snap-over process, so that the edge portion 32 folds slightly outwards to the side and causes the latching ring 39 to snap into the groove 13b. In the concave top wall position of FIG. 3b, the latching ring 39 presses laterally from the inside into the annular groove 13b of the opening wall 12b and thus locks the lid 30 into its closed position. The material is stretched in the expansion portions 34 into a--when seen in a plan view--widened state and the outer diameter of the edge portion 32 increases during this folding process. FIG. 3c shows in detail the engagement of the ring 39 into the groove 13b.

[0055] To uncover the opening 11b again, the lid 30 must snap back into its original state. It can then be pulled out of the opening 11b due to its reduced outer diameter. Conventionally, a handle member on the top wall 31 was provided for this purpose. By the handle member, the lid 30 could be seized and pulled upwards. As described in detail below, the second embodiment of the present invention also allows the lid to be opened with a force F.sub.4, F.sub.5 acting laterally (transversely to the direction of attachment) on the container wall 12b, so that the handle member can be dispensed with.

[0056] As can be seen best in the enlarged representation of FIG. 3c, the protrusion 14b has a length b1 up to the outermost (opposite to the direction of attachment) end of the wall region 12b. If the user now exerts, transversely to the direction of attachment, from the outside at the pressure point B2 a force F.sub.4 on the wall region 12b, this force, with the length b1 acting as a lever arm and with the contact point B1 between wall region 12b and edge portion 32, acts by the elastic deformation of the protrusion 14b in such a way on the cover 30 that the cover 30 can snap into the open state without the need for any direct pressing of the edge portion 32 or pulling of the top wall 31 via a handle member or the like.

[0057] As shown in FIG. 3d, the protrusion 14b' can also be longer according to a first modification of the second embodiment. This not only extends the lever arm to the length b2 and reduces the force F.sub.5 required to open the cover 30, but the cover 30 is then also completely protected inside the opening 11b, which makes any unintentional opening of the closure system more unlikely.

[0058] FIG. 3e shows a second modification of the second embodiment. Here, the wall region 12b below the inner groove 13b has an opening in which a slider 13c is mounted. The slider 13c is a rod-shaped actuating element for opening the cover 30 and can be displaced in the opening transversely to the direction of attachment. For this purpose, the user exerts a force F.sub.5' on the actuator 13d mounted to or integrally formed with the outer end of the slider 13c from outside transversely to the direction of attachment. In the modification of the embodiment shown, the actuator 13d has the shape of a hemispherical actuating knob.

[0059] The other end of the slider 13c meets the end of an edge portion extension 34 protruding in the direction of attachment from the edge portion 32 inside the container 10b. The extension 34 can be attached to or integrally formed with the edge portion 32 in partial areas or over the entire circumference. In the modification shown, the extension essentially has a length b3 and is thus longer than the edge portion 32 as such. The extension 34 acts as a lever arm of the length b3 up to the transition region between edge portion 32 and top wall 31.

[0060] If the slider 13c is pushed inwards with the minimum force F.sub.5' at the actuator 13d, the extension 34 is moved such far into the interior of the container that it transfers, to the top wall 31 via the lever arm b3, the torque necessary for switching into the open bistable state. The same force F.sub.5' when acting on the remaining wall region 12b would not be sufficient for opening of the cover 30--for example, because the wall thickness or strength of the container wall is large enough to make force transmission to the edge portion extension 34 sufficiently difficult. This additionally increases safety against any unintentional opening of the box-lid system.

[0061] As shown in the third modification of the second embodiment in FIG. 3f, the slider 13c and the actuator 13d can also be omitted. Instead, the wall region 12b may have a constriction 13e where the wall thickness is weakened. The constriction 13e can be provided as a circumferential ring-shaped recess or only as a grasping recess arranged in partial areas, preferably at two diametrically opposed points. If the minimum force F.sub.5'' is used to press the wall region at the area of the constriction 13e radially inwards, the extension 34 deforms towards the inside of the container to such an extent that it transfers the torque required to switch the top wall 31 via the lever arm b3 into the open bistable state. Apart from the wall thickness weakened by the constriction 13e, the container wall 12b is strong enough to prevent unintentional opening with the force F.sub.5''. This avoids any impairing of the container tightness which may arise in the second modification with the wall opening and the slide 13c. On the other hand, for certain applications such wall breakthroughs are desirable, e.g. for pressure equalization between the container inside and ambient pressure. Instead of the constriction 13e, the wall region 12b can also be softened at this location in another way, for example by using a softer material component or subsequently softening the wall region 12b at this location.

[0062] In summary, the present invention relates to a closure system with a three-dimensional structure 10a, 10b, in particular a container or an opening region of a technical apparatus, and a cover 20, 30 for fitting onto the three-dimensional structure 10a, 10b in order to close its opening 11a, 11b. The cover 20, 30 has a top wall 21, 31 which is deformable in a bistable manner between a first state curved in the direction of attachment and a second state curved opposite to the direction of attachment, and an annular edge portion 22, 32. The edge portion has a larger outer circumference in the first bistable state than in the second bistable state and is therefore adapted to effect a clamping attachment of the cover 20, 30 to a wall region 12a, 12b of the opening 11a, 11 b by the edge portion 22, 32 pressing against the wall region 12a, 12b in the first state from inside or pressing against the wall region 12a, 12b in the second state from outside. The three-dimensional structure 10a, 10b is configured to transfer a force exerted on the closure system at predefined locations A2, B2 from the outside in such a way that it leads to a snapping of the cover 20, 30 from one to the other of the two bistable states.

LIST OF REFERENCE SIGNS

[0063] 10a, 10b container

[0064] 11a, 11b opening

[0065] 12a, 12b sidewall

[0066] 13a outer groove

[0067] 13b inner groove

[0068] 13c wall penetration with slider

[0069] 13d actuator

[0070] 13e constriction

[0071] 14a, 14b, 14b' protrusion

[0072] 15a, 15b step

[0073] 16, 16' end section

[0074] 17 narrowing element

[0075] 18 extension of edge portion of cap

[0076] 19 extension of top wall

[0077] 20, 30 cover

[0078] 20 cap

[0079] 30 lid

[0080] 21, 31 top wall

[0081] 22, 32 edge portion

[0082] 23, 33 intermediate portions (hard)

[0083] 24 expansion portions (soft)

[0084] 23a lip portion inside (hard)

[0085] 24a lip portion inside (soft)

[0086] 29 inner latching ring (soft)

[0087] 33a lip portion outside (hard)

[0088] 34 extension of edge portion of cover

[0089] 39 outer latching ring (soft)

[0090] a1, b1, a2, a2', b2, b3 lever arms

[0091] A1, B1 contact point

[0092] A2, B2 pressure point

Claims

1-20. (canceled)

21. A closure system, comprising: a three-dimensional structure having an opening to be closed; and a cover for attachment onto said three-dimensional structure to close said opening, said cover comprising: a top wall that is deformable in a bistable manner between a first bistable state which is cambered in a direction of attachment and a second bistable state which is cambered opposite to the direction of attachment; and an annular edge portion having an outer circumference that is greater in the first bistable state than in the second bistable state and being configured to effect a clamping attachment of said cover to a wall region of said opening by pressing said edge portion in the first state from inside or in said second state from outside against said wall region; and said three-dimensional structure being configured to transfer a force exerted on the closure system from outside at at least one predefined location to cause said cover to snap from one of the two bistable states to another of the two bistable states.

22. The closure system according to claim 21, wherein: in a closed state of the closure system, the edge portion of said cover presses in the first state at a contact point from inside against said wall region; and said three-dimensional structure, at least at the at least one predefined location, is formed of a material which is so flexible that a force acting transversely to the direction of attachment on said wall region of said opening from at least one outer side or from two opposite outer sides causes said cover to snap from the first bistable state to the second bistable state.

23. The closure system according to claim 22, wherein: said wall region has at least one narrowing point at which a size of said opening decreases; and the size of said cover is dimensioned such that, in the open state of the closure system, said cover fits into said opening only up to the narrowing point thereof and rests with the edge portion against the narrowing point.

24. The closure system according to claim 23 wherein, in order to open the closure system: a force acting transversely to the direction of attachment from two opposite outer sides acts on the wall region of said opening at a pressure point which is spaced from a narrowing point in the direction opposite to the direction of attachment; and the force acts via a lever arm formed by a distance between the pressure point and the contact point on the edge portion abutting at the narrowing point and causes said cover to snap from the first bistable state into the second bistable state.

25. The closure system according to claim 23, wherein the wall region is formed with a groove, which is spaced from the narrowing point in the direction opposite to the direction of attachment and which is configured to engage with a clamping element of the edge portion of said cover.

26. The closure system according to claim 21, wherein: an extension in the direction of attachment is attached to or integrally formed with the edge portion and extends, in the closed state of the cover in the direction of attachment, at least up to the predefined location of the three-dimensional structure, and transfers a force acting from two opposite outer sides of the wall region to the top wall in such a manner that the top wall snaps from the first bistable state to the second bistable state; and the wall region has a penetration at the predefined location with a sliding element which extends transversely to the direction of attachment and is movable transversely to the direction of attachment on account of the force acting from the at least one opposite outer side of the wall region so that it is being pressed against the extension in order to open the cover.

27. The closure system according to claim 21, wherein: in a closed state of the closure system, the edge portion of the cover presses in the second state at a contact point from outside against the wall region; and the wall region at an outermost end portion thereof, when seen opposite to the direction of attachment, is shaped such that a snap-over of said cover from the first bistable state to the second bistable state and thus a closing of the closure system cannot only be effected by a force acting transversely to the direction of attachment from two opposite sides on the edge portion of the cover but also by a force acting in the direction of attachment on a predefined location of the top wall.

28. The closure system according to claim 27, wherein: the outermost end portion of said opening wall is shaped such that, in the open state of the closure system, the top wall of the cover contacts the opening wall at a contact point which is closer to the center of the opening than the transition region between the top wall and the edge portion; and a force acting on the region of the top wall of said cover in the direction of attachment at a pressure point acts on the edge portion via a lever arm formed between the pressure point and the contact point and causes said cover to snap over from the first bistable state to the second bistable state.

29. The closure system according to claim 28, wherein the outermost end portion of the opening wall has a shape which tapers transversely to the direction of attachment.

30. The closure system according to claim 28, wherein the opening narrows at the outermost end portion of the opening wall.

31. The closure system according to claim 28, further comprising: an extension extending substantially in the direction of attachment mounted or integrally formed at the edge portion and extending the lever arm of the force, said force acting transversely to the direction of attachment from at least one and preferably from two opposite outer sides on the edge portion for closing the closure system; and/or an extension extending substantially transversely to the direction of attachment attached or integrally formed at the top wall and extending the lever arm of the force, said force acting in the direction of attachment on the predefined location for closing the closure system.

32. The closure system according to claim 21, wherein said three-dimensional structure is a container.

33. The closure system according to claim 21, wherein the edge portion of said cover comprises at least one expansion portion formed of a second material component which is softer than a harder first material component forming a remaining edge portion and allowing a widening of the outer periphery of the edge portion in the first bistable state relative to the second bistable state.

34. The closure system according to claim 33, wherein said cover is integrally made of plastics by a multi-component injection molding process.

35. The closure system according to claim 33, wherein the edge portion of said cover comprises a plurality of expansion portions of the softer second material component which, starting from a transition region between the edge portion and the top wall, alternate equidistantly with intermediate portions of the harder first material component of the remaining edge portion.

36. The closure system according to claim 21, wherein the top wall merges into the edge portion with a constant angle that remains the same in the first bistable state and in the second bistable state.

37. The closure system according to claim 21, wherein a material thickness at a transition from the top wall to the edge portion is at least in partial regions greater than in a remaining region of said cover.

38. The closure system according to claim 21, wherein said cover, at a transition from the top wall to the edge portion, is formed, at least in partial regions thereof, from a material component that is harder than a material component forming a remaining said top wall and an entire said cover has a substantially uniform material thickness.

39. The closure system according to claim 33, wherein the edge portion in and outside the region with the expansion portion has a central portion extending axially in the direction of attachment or opposite thereto, and a lip portion adjacent to the central portion and extending radially inwards and/or outwards.

40. The closure system according to claim 33, further comprising a latching ring integrally formed at an end region of the edge portion or the lip portion, said latching ring being formed of a material which is softer or more elastic than the first material component.