BOX LID

Abstract

This is a described resealable can lid which has a neck part and a plastic receiving part which are coupled together by a locking connection, in which a self-contained tear line is either partially broken or formed as a toothed joint line, and the inside of the can lid provided that the sealing film is ensured.

Description

[0001] The invention relates to a can lid with a tightly resealable opening according to the preamble of claim 1.

[0002] Such a resealable can lid is known from DE 10 2010 013 531 A1.

[0003] Furthermore, a comparable can lid of this type is described in EP 2 354 022 B1. Document EP2354022 discloses a can lid according to the preamble of claim 1.

[0004] From EP 1 607 341 A1, a can lid with a resealable opening is known, in which an opening is provided in the metal can lid and the edge of this opening is crimped to create an anchoring point for a prefabricated plastic closure element. The plastic closure element comprises a base part that is to be connected to the crimped edge of the can opening, in which an opening is formed that is closed by a flat plug. The flat plug is connected to the edge of the opening via a plastic tear strip, so that the flat plug, which is connected to a tear tab, can be detached from the plastic base part by pulling on the tear tab and pivoted into an open position. The opening can be temporarily closed again by pressing in the flat plug, which is preferably conical on its underside.

[0005] WO 2008 / 098558 A1 discloses a can lid with a resealable opening, in which an opening is also provided in the metal can lid into which a pre-made, tear-open plastic closure element is inserted. The pre-made plastic element has a double flange on its edge, into which the edge of the punched-out can opening engages and is fixed. The pre-made plastic element comprises a closure element that is connected to the circumferential edge of the plastic element via a tear seam. A tear tab connected to the closure element allows the plastic tear seam between the circumferential area of ​​the plastic element and the lid element to be torn open, thus releasing the can opening. For the purpose of resealing, the closure element, which preferably remains connected to the circumferential area via a tab, can be pressed back into the opening.

[0006] From GB 1 389 351, a resealable can lid is known which is designed to prevent the formation of sharp edges, such as those that occur when opening conventional tin cans using a tab. For this purpose, a pre-fabricated plastic part is snapped into a cutout in the metal can lid. This plastic part has a lid section that is connected to the base section, which is snapped into the can opening, via a thin plastic wall. A tear-off tab allows the thin connecting wall between the closure section and the base section to be broken, thus exposing the can opening. The closure section is designed to engage with the base section via a snap-lock connection to reseal the opening.

[0007] From DE 89 11 286 U a beverage can with a push-in lid closure is known, in which the tear tab is rotatably mounted on the lid wall and a closure element is provided on it, which, when the tear tab is turned from the opening position to a closing position above the open pouring opening, covers the pouring opening or engages in it in a closing manner.

[0008] From DE 90 05 150 U a beverage can with a lid made of sheet metal is known in which a weakening line is formed and the lid part delimited by the weakening line can be removed by means of a pull tab, wherein a captive closure part for the dispensing opening is attached to the lid which is pivotable essentially parallel to the lid surface.

[0009] From DE 196 13 246, a metal lid for beverage cans is known which has a pre-cut pouring opening in the lid surface, which is tightly sealed by means of a locking element and can be tightly resealed after the first opening. The lid and locking element can be positively connected to each other by bayonet-like interlocking elements that are formed directly from the lid material and the locking element, respectively.

[0010] The object of the present invention is to further develop the resealable can lid according to the preamble of claim 1 in such a way that, while maintaining a high-quality, gas- and liquid-tight closure, the functionality is further improved and, in particular, the process of opening the can is made easier or the force required for this is reduced, and that, furthermore, due to the design, the manufacture of the can lid can be simplified, made more cost-effective and the automatic assembly can be made significantly cheaper compared to previous solutions.

[0011] This problem is essentially solved by the fact that the collar part and the lid receiving part each have a plurality of molded and ring-shaped distributed projections, that these projections extend through adapted openings in the metallic lid part, and that the collar part and the lid receiving part are connected to the metallic lid part in a form-fitting and force-fit and tight manner by means of rivet-like deformation of the projections under the influence of heat, with the interposition of an adhesion-promoting layer.

[0012] These measures enable separate manufacturing of the plastic and metal components and avoid the injection molding of composite parts made of metal and plastic, thereby achieving significant manufacturing advantages without any functional losses.

[0013] To achieve secure and permanent connections between the individual components of the can lid, it is preferably provided that the adhesion promoter or sealing layer, which reacts at elevated temperature, extends over both surfaces of the metallic lid part, i.e. over the outer and inner surfaces of this lid part.

[0014] The sealing layer provided, which may be a sealing lacquer, ensures that the plastic materials are tightly and firmly bonded to the metal parts, preferably by heat sealing at elevated temperature, for example at about 150°C to 160°C.

[0015] One embodiment of the invention is characterized in that the opening area, which is bounded by a circumferential tear line, is connected to the adjacent lid area by a weakening groove, which is partially perforated, particularly in the initial and final areas associated with the tearing movement.

[0016] By providing appropriately arranged partial perforations in the weakening groove, the force required to open the closure can be reduced in a defined manner, while still ensuring a tight seal by means of the layer of plastic material or the correspondingly applied plastic film that is provided and firmly attached to the entire surface of the underside of the metallic lid.

[0017] According to a further embodiment of the invention, a significant advantage in terms of manufacturing technology arises from the fact that the collar part, the lid receiving part and the pull tab are made of the same plastic material, in particular polypropylene, and are formed from a single injection-molded part connected by connecting tabs, which can be transformed into an assembly unit by folding and can be connected to the metallic lid part in one connection step via the projections assigned to the openings in the metallic lid part.

[0018] This is made possible primarily by the fact that the metal can lid is fully coated on both sides with the aforementioned sealing layer. This layer allows all plastic components or parts to be injection-molded from a single material, especially polypropylene, in one operation, while still ensuring strong and tight connections with the metal can lid. The three interconnected components, made from the same plastic material, are folded together to form a single unit. By pressing the protrusions on the plastic parts into the corresponding openings in the can lid, a rivet-like connection and heat sealing can be achieved, activating the sealing layer.

[0019] According to a further embodiment of the invention, to ensure the long-term tightness of the overall arrangement, the lid receiving part is provided to be tightly connected to the metallic lid part by heat sealing with its outer circumferential edge which abuts the metallic lid part.

[0020] The pull tab preferably has at least one projection extending to the metallic lid part, which is connected to the lid part during a sealing step.

[0021] A snap-lock connection, which is generally particularly advantageous for closures of containers with a lid part, is characterized by the fact that the snap-lock connection between the collar part and the lid receiving part consists of a coupling and sealing rib provided on the lid receiving part, which engages in a first adapted recess in the collar part, and a pre-tensioning and locking lip, which engages in a second recess of the collar part in a locking manner and presses the wall rib between the two recesses against the coupling and sealing rib.

[0022] A further embodiment of the invention, which is particularly advantageous regardless of the type of connection between the plastic parts and the metal parts and regardless of whether only one plastic material or several plastic materials are used, is characterized in that the opening area of ​​the metallic can lid is separated from the surrounding lid surface by a cutting, in particular punching, process, forming interlocking projections and recesses, that the opening area and the surrounding lid surface are held together as one component by means of these projections and recesses in a form-fit and force-fit manner, and that the tightness of the finished, unopened can lid is ensured by the inner plastic coating or film.

[0023] The projections and recesses are preferably coupled via undercuts.

[0024] This particularly significant embodiment of the invention, in which the opening area of ​​the can lid is first cut or punched out to form a toothed structure, and immediately thereafter this punched-out lid opening area is pressed into the toothing of the remaining part of the can lid, thus creating a one-piece structure that can be moved to the next station in production and joined with the plastic part, results in an absolutely chip-free opening of the hinged lid part and the opening process requiring very little force. This is because no metallic weakening grooves need to be torn open during the opening process, as the metallic areas to be separated are already completely separated from each other by the punching process.The tightness of this arrangement is again ensured by the inner plastic film, which has a circumferential weak point or indentation immediately adjacent to the opening area, so that the opening process is not made more difficult by this film which ensures tightness.

[0025] Exemplary embodiments of the invention are described below with reference to the drawing.

[0026] The drawing shows: Fig. 1 a top view of a resealable can lid according to the invention, Fig. 2 a perspective view of the stamped metallic lid surface before connection with the plastic components of the closure, Fig. 3 a perspective sectional view of the can lid according to Fig. 1 Fig. 4 is an enlarged detail to illustrate the sealing coupling between a collar part connected to the container and a lid receiving part; Figs. 5A to 5C show illustrations to explain the manufacturing of all plastic components of the closure in one manufacturing step; Fig. 6 is a perspective top view of a particularly preferred embodiment of the metallic can lid part before connection with the plastic components; and Fig. 7 is a sectional view of the can lid after Fig. 6 with schematically drawn plastic components.

[0027] Fig. 1 Figure 1 shows a can lid 1 made of metal, which is conventionally designed in its basic form and is connected to the respective can in a liquid- and gas-tight manner via a crimped edge 2 and the insertion of a sealing material.

[0028] This lid has an integrated, off-center, resealable opening, as will be explained in detail later.

[0029] In Fig. 1 A collar part 5, connected to a tear-off tab 15, can be seen. This collar part encloses the opening area and is firmly connected to the can lid surface 23. A lid-receiving part 10 encloses the opening area 11 and can be pivoted upwards by means of the tab 15 during the opening process. A hinge spring element 22 ensures that the pivoted lid is held in the open position, particularly when it is opened from an angle greater than 90°.

[0030] The Fig. 1 It can also be inferred that the resealable opening with all its associated components is arranged off-center in such a way that, despite the presence of the resealable opening, the stackability remains unchanged, just like with conventional cans.

[0031] Besides the positioning, the compactness of the resealable opening according to the invention is a prerequisite for this. According to the invention, the protrusion of the components of the resealable opening beyond the can surface is only about 2 mm.

[0032] Fig. 2 shows the metallic can lid, designed as a stamped part, of an advantageous embodiment of the invention before connection with the associated plastic components of the resealable lid.

[0033] This illustration shows through openings 31, which serve to connect the plastic components to the metallic can lid and are arranged in a ring shape on both sides of a weakening groove or tear notch 4. A special feature of the design of the weakening groove or tear notch 4 is that, unlike conventional solutions, it is not through-holes but has openings 36, which have the advantageous effect of facilitating the opening process, i.e., reducing the force required to open the pivoting lid part. These openings 36 are formed during the stamping process of the lid, but the lid part remains a single stamped part.The tightness to be ensured by the can lid is not affected by the perforations 36, because the required tightness is ensured by an internal sealing film extending over the entire inner surface of the can lid and also into the crimped area.

[0034] Fig. 3 shows a cross-sectional view of the can lid according to the Fig. 1 and 2 , where the arrangement is shown in the closed state.

[0035] The area of ​​the can lid located within the tear line 4, i.e., the opening area 11, is enclosed by a lid receiving part 10 made of plastic, which is firmly and tightly connected to this metallic area by means of a plurality of molded projections 32, which are characterized by the details in Fig. 2 The openings 31 shown extend. A strong connection is created by rivet-like deformation of these projections 32 under the influence of heat, whereby it is essential that a heat-reacting adhesion promoter is provided on the contact surfaces between the plastic part and the metal part. Preferably, both the outer and inner surfaces of the metal can lid are coated with a suitable material effective as an adhesion promoter, in particular in the manner of a sealing lacquer, so that the adhesion promoter is available wherever it is required for joining and sealing purposes.

[0036] For interaction with the lid receiving part 10 in the form of a snap-lock connection, a collar part 5 made of plastic material is provided radially outside the opening area, which is connected to the metallic can lid in the same way as the lid receiving part 10 via projections 30 passing through openings 31.

[0037] For both the chosen joining technique between metal and plastic parts and, in particular, for the design of the tear line or weakening groove 4, the provision of a plastic layer or film is important. This layer extends over the entire underside of the can lid up to the area of ​​the crimped edge 2 and completely covers this underside. This plastic layer 26 is bonded to the metallic can lid by means of an adhesion promoter, in particular a lacquer that becomes active or reacts upon application of heat. Fig. 3 This shows that this sealing layer extends both over the mechanical connection points between metal and plastic parts and over the weakening groove 4.

[0038] The main advantage of the described connection technology between the metallic lid and the plastic components is that the metal stamping part and the plastic parts can be manufactured separately, no metal overmolding processes are required, and the connection between the metallic can lid and the plastic components can be made in one operation when the plastic components are applied to the metallic surface and the projections 30 penetrate the openings 31.

[0039] The detailed presentation after Fig. 4 shows a design principle that can be used in principle for snap-fit ​​connections in general, and which is advantageously also used for the resealable can lid according to the invention.

[0040] The lid receiving part 10 is provided with two circumferential ribs: an outer dome and sealing rib 34 and an inner pretensioning and locking rib 35. The dome and sealing rib 34 engages in a first recess 39 of the collar part 5, sealingly, while the pretensioning and locking rib 35 extends into a second recess 40 of the collar part 5, creating a snap-fit ​​connection between this rib and the recess. Crucially, this rib 35 is dimensioned and designed such that, in the locked position, it presses against the central wall rib 41 of the collar part, thus pressing this wall part against the sealing rib 39 and thereby further improving the sealing effect.

[0041] Fig. 4 This also shows that the metallic can lid is covered on both sides and completely with an adhesive layer 37, which also makes it possible to fix the outer edge of the lid receiving part 10, which rests on the metallic can lid surface, in a sealing manner via the adhesive layer in order to improve the tightness of a filled can.

[0042] For a resealable can lid, not only must requirements regarding sealing be met, but above all, the can must be opened easily and with minimal effort. The easily and conveniently gripped pull tab 15 contributes to this, but, more importantly for the invention, the required tearing force must be as low as possible. This objective is achieved by the aforementioned provision of openings 36 along the tear line or the weakening groove. Furthermore, the inner plastic film 26 is provided with a circumferential weakening notch 38 adjacent to the tear line, so that the film 26 does not impede the opening process.

[0043] The depictions in the Fig. 5a bis 5c show a particularly advantageous embodiment of the invention, which consists in that all plastic components of the resealable can lid are made of the same plastic material and that these plastic components can therefore be manufactured in a single injection molding process.

[0044] As can be seen from the illustrations, collar part 5, lid receiving part 10 and pull tab 15 are injection molded lying in one plane and connected to each other by connecting tabs 42, so that a practically one-piece overall structure is obtained which can be handled as a unit in the manufacturing process and only needs to be folded on top of each other for assembly on the can lid, so that the then approximately concentric projections 30 of collar part 5 and lid receiving part 10 can be pressed through the openings 31 in the metallic can lid in a single pressing operation and then deformed in the manner already described.

[0045] In addition to the simplification of the production of the plastic components made of the same material and reacting with the suitable adhesion promoter 37, which can be achieved in this way, a corresponding handling and assembly advantage is also evidently obtained.

[0046] Fig. 6 shows a particularly preferred embodiment of a can lid according to the invention, wherein the Fig. 6 shown metallic can lid part, in particular with the plastic elements according to Fig. 5 which can be combined to create a finished, resealable can lid.

[0047] While with known resealable standard can lids, opening them results in undesirable and unavoidable chip formation or the creation of tiny metallic aluminum particles due to the tearing open of a metallic weakening groove, the design according to the invention allows this to happen. Fig. 6 to ensure completely chip-free opening that eliminates health risks.

[0048] For this purpose, the opening area 11 of the metallic can lid is separated from the surrounding outer, solid lid surface 43 by a cutting or, in particular, a punching process, forming interlocking projections 32 and recesses 33, as is the case, for example, in Fig. 6 shown.

[0049] Immediately after the preferably used punching process, the two initially separated parts are positively joined together, so that the two parts effectively become one part again, which can be handled as a single unit. The separation and joining processes occur directly one after the other; that is, the punching stroke is followed in the return stroke by the positive-locking joining of both parts to form a complete component. The positive and non-positive connection between the two parts is achieved through suitable shaping or by using undercuts, which ensure sufficient mutual mechanical connection to allow the previously separated parts to be handled again as a single assembly component in manufacturing.

[0050] If the plastic components after Fig. 5 with the metallic can lid part after Fig. 6 Since the components are tightly connected to each other in the manner already described, and the rear plastic film 26 is also applied, the arrangement is as shown schematically in a sectional view in Fig. 7 shown.

[0051] In the representation according to Fig. 7 Collar part 5 and lid receiving part 10 are tightly and permanently connected to the metallic can lid part in the manner already described, and the snap-lock connection is engaged. The seal is ensured by the foil 26 extending to the crimped edge. The tear line 4 is formed by the dividing line between the interlocking projections 32 and recesses 33.

[0052] When the filled can is opened via the pull tab, the projections 32 and recesses 33 defining the tear line are disengaged, but no weakened metal areas need to be separated from each other with chip formation; only the existing positive locking connection needs to be released, which is possible with significantly less force than is required to tear open a still existing metallic connection between the two parts to be separated.

[0053] The previously mentioned use of the weakening notch 38 in the inner sealing film contributes to the fact that the requirements placed on such a resealable can lid, both in terms of tightness and minimized opening force, can be optimally met, while at the same time ensuring economical manufacturing and assembly of all can lid components. Bezugszeichenliste

[0054] 1 Metallic can lid 2 Rolled edge 3 Lid surface 4 Weakening groove or tear line 5 Collar part 10 Lid receiving part 11 Opening area 15 Pull tab 22 Spring clip part 23 Can lid surface 26 Sealing plastic layer, film 30 Attachment 31 Opening 32 Projection 33 Recess 34 Coupling and sealing rib 35 Tension and locking rib 36 Through hole 37 Adhesion promoter, sealing lacquer 38 Weakening notch 39 First recess 40 Second recess 41 Wall rib 42 Connecting tab 43 Outer fixed lid surface

Claims

1. A can lid having a sealingly reclosable opening, in particular for beverage cans, comprising a bounded opening region (11) provided in the metallic lid material of a lid surface (3) as well as a two-armed lifting member intended to open this opening region (11), said lifting member being connected to a pull tab (15), on the one hand, and engaging at the opening region (11) of the lid surface (3), on the other hand, and being supported via a bearing translating the opening force applied to the pull tab (15), wherein the opening region (11) is configured as a closure lid and is connected at its outer margin in a force-transmitting manner to a collar part (5) composed of a plastic material and a lid receiving part (10) is associated with the collar part (5), said lid receiving part (10) being connected in a force-transmitting manner to the lid surface (3) outside the opening region (11) and being composed of a plastic material; wherein the collar part (5) furthermore engages over the lid receiving part (10) and a sealing snap-in latching connection having at least one peripheral coupling rib (34) and a cut-out (39) shaped in complementary form thereto is formed between the collar part (5) and the lid receiving part (10); wherein the pull tab (15) is fastened radially outside the lid receiving part (10) to a fixing region of the collar part (5) and the two-armed lever for opening the opening region is formed at a partial peripheral region of the collar part (5) associated with the fixing region (5); and wherein the lower side of the metallic lid is in particular coated in a firmly adhesive manner over the full surface with a plastic material and this coating is attenuated or thinner surrounding the opening region, characterized in that the collar part (5) and the lid receiving part (10) each have a plurality of molded noses (30) arranged distributed in an annular manner; in that these noses (30) extend through adapted openings (31) in the metallic lid part; and in that the collar part (5) and the lid receiving part (10) are connected to the metallic lid part in a shape-matched and force-transmitting manner as well as sealingly by a rivet-like deformation of the noses (30) under the effect of heat while interposing an adhesive promoting layer (37).

2. A can lid in accordance with claim 1, characterized in that the adhesive promoting layer or sealing layer reacting at an elevated temperature extends over both surfaces of the metallic lid part, i.e. over the outer and inner surfaces of this lid part.

3. A can lid in accordance with claim 1 or claim 2, characterized in that the opening region (11) bounded by a peripheral tear line is connected to the adjacent lid region by an attenuating groove (4) which is perforated at least in part, in particular in the starting and end regions associated with the tear movement.

4. A can lid in accordance with one or more of the preceding claims, characterized in that the collar part (5), the lid receiving part (10) and the pull tab (15) comprise the same plastic material, in particular polypropylene, and are formed by an injection molded part which coheres via connection tabs, which can be transformed into an assembly unit by folding and which can be connected to the metallic lid part via the noses (30) in a connection step.

5. A can lid in accordance with any one of the preceding claims, characterized in that the lid receiving part (10) is sealingly connected at its outer peripheral margin contacting the metallic lid part to this metallic lid part by heat sealing.

6. A can lid in accordance with claim 5, characterized in that the pull tab (15) has a nose which extends up to the metallic lid part and which is connected to the lid part by sealing.

7. A can lid, in particular in accordance with one or more of the preceding claims, characterized in that the snap-in latching connection between the collar part (5) and the lid receiving part (10) comprises a coupling and sealing rib (34) which is provided at the lid receiving part (10) and which engages into a first adapted recess in the collar part (5) and comprises a preloading and latching rib (35) which latchingly engages into a second recess of the collar part and presses the wall rib between the two recesses toward the coupling and sealing rib (34).

8. A can lid in accordance with one or more of the claims 1 to 7, characterized in that the opening region (11) of the metallic can lid (1) is separated from the lid surface surrounding it while forming mutually engaging projections (32) and recesses (33) by a cutting process, in particular a punching process; in that the opening region (11) and the lid surface surrounding it are held together as a component in a shape-matched and force-transmitting manner via these projections (32) and recesses (33); and in that the leak-tightness of the finished, unopened can lid is ensured by the inwardly disposed plastic coating or film.

9. A can lid in accordance with claim 8, characterized in that the projections (32) and recesses (33) are coupled via undercuts.