GB2532418A

GB2532418A - Closure

Info

Publication number: GB2532418A
Application number: GB1420268.3A
Authority: GB
Inventors: Robert Dunwoody Paul
Original assignee: Crown Packaging Technology Inc
Current assignee: Crown Packaging Technology Inc
Priority date: 2014-11-14
Filing date: 2014-11-14
Publication date: 2016-05-25
Also published as: GB201420268D0; WO2016074996A1

Abstract

A closure 1 for a container, the closure comprising an end panel 3, a sidewall 4 depending from the end panel for extending circumferentially around the container, and a brim 5, which is located radially outward of the sidewall and which is connected to the sidewall by a multiplicity of spokes 6. The spokes extend with a radial component between the sidewall and the brim such that movement of the brim relative to the sidewall creates a radially outward pulling force to loosen the grip of the closure on the container during opening. Weakening lines may extend from the spokes into the sidewall, and wherein at least part of the sidewall and optionally the spokes may be crimped to a neck of the container. The container may be one of a beverage can, a metal bottle, and a glass or plastic bottle. The brim may be terminated at its periphery with a curled edge. Rotation of the brim about the container may permanently distort or tear a part of the closure to provide evidence of such rotation.

Description

Closure

Field of the Invention

The invention relates to a closure for a container, a container adapted to accommodate the closure, and to a method of manufacture of a closure and a container.

Background

Many types of closure are known for cans, jars and bottles, with most requiring some type of thread or rolled seam or crimp to hold them in place. In some cases, a partial vacuum inside the containers is used to help retain the closure.

Closures (commonly known as "easy-open ends") that are currently available for beverage cans are typically fixed permanently to the can body by seaming the closure onto the flanged open end of the can body after filling, and an aperture is farmed during opening by tearing a scored region of the closure. These closures have a tab component attached in order to open around the score. If the closure is of the "stayon-tab" type, then the space available for the aperture is limited. If a "full-aperture" is required, then the tab, attached together with the unsafe sharp-edged metal part from the aperture, is detached during opening and requires safe disposal. Neither of these closure types is re-closable. Re-closable beverage can closures are available (for example as described in US6206222), but these generally comprise expensive plastic moulded valves which restrict the aperture available for drinking or pouring.

Easy-open ends for beverage cans are commonly available to suit cans with open ends down to around 50mm. Below this size, seaming of ends onto cans becomes more difficult, and there is less space available for the scored aperture, the tab and its attachment.

Beverage cans having an opening smaller than 38mm in diameter are generally referred to as metal bottles, and are commonly used with types of closures suited to glass or plastic bottles. Provision of curls and threads at the openings of metal bottles often requires several manufacturing process steps and complex tooling. Threads are more complex to manufacture than simple curls, but are commonly the only option available for metal bottle apertures greater than around 20mm in diameter.

It is therefore currently difficult to provide cost-effective easy-to-open closures or pressurised metal beverage cans or bottles having apertures between 20 and 50mm, and even more so for apertures between 30 and 45mm.

Closures for bottles and jars, such as "Crown" closures that are typically used for bottled beverages, may be applied by pressing them onto a bottle and crimping.

However, these normally require a tool to open and are only commonly available to suit bottles with narrow openings up to around 20mm in diameter. "Twist-Off-Crowns" are available that can be released by twisting, but these can be uncomfortable and even injurious to open, and require the bottle to have moulded screw threads to create a mating thread during crimping. "Twist-Off-Crowns" are not commonly used on metal bottles due to the inability to provide threads of sufficient strength.

Another type of closure, known as Maxi-Crown and described in US 4768667 A, is available that can be crimped on and torn open, but this exposes sharp edges after opening and requires safe disposal.

Closures are available for bottles and jars that are pressed-on over a thread on the container, such that the sealing material within the closure conforms to the thread and enables them to be twisted off. Such closures are commonly used for small quantities of foodstuffs such as spreads and baby-food in glass jars. However the threads and the sealing material have to be accurately formed and the sealing material must be specially formulated, and so manufacturing costs are high.

Closures may be screwed onto cans, bottles and jars that have screw threads. Such closures may have corresponding screw threads, lugs that engage with the container threads, or may have a plain metal surface that can be rolled to conform to the container threads. All such closures are twisted to remove them.

All the closure types described above have both advantages and disadvantages. Closures that require twisting to open them are less prone to unintentional opening by accidental impacts, but it is often expensive and difficult to provide the necessary screw threads. Closures that do not require twisting are generally crimped tightly and require a tool to remove them. When a crimped closure is opened, it is usually distorted such that the closure cannot be used to re-close the container. This has the advantage that there is evidence that the container has been opened (tamper-evidence), but the disadvantage that it cannot be reclosed.

Closures may be provided with slits or cuts to create joining regions that might be defined as spokes, to be torn to create a separate band when opened. This provides evidence of opening and additional security before opening. Typical examples are aluminium "roll-on pilfer-proof" capsules for wine and other bottles, and plastic caps with tear bands for containers such as plastic milk containers. However, it is not always desirable for the closure to be torn when opened as this exposes sharp edges.

Often it is not practical to provide a container and closure made from the same material, which hinders recycling.

Summary

It is an object of the present invention to provide a 'Tull-aperture" pressure-resistant closure that may be simply crimped or rolled onto a container, that may require only twisting by hand to open, but that does not require threads on the closure or the container or a tool to open. Moreover, it is an object to provide such a closure that may be re-closable, tamper-evident, safe to handle, and may be made from the same material as the container.

According to a first aspect of the invention there is provided a closure for a container, the closure comprising an end panel, a sidewall depending from the end panel for extending circumferentially around the container, and a brim which is located radially outward of the sidewall and which is connected to the sidewall by a multiplicity of spokes. The spokes extend with a radial component between the sidewall and the brim such that movement of the brim relative to the sidewall creates a radially outward pulling force to loosen the grip of the closure on the container during opening.

The brim may be configured such that, when the closure is affixed to a container, rotation of the brim about the container is substantially not impeded by the container other than by forces exerted on the brim by the spokes.

The closure may be configured such that, when affixed to a container, rotation of the brim about the container permanently distorts or tears a part of the closure to provide evidence of such rotation.

The closure may have a central panel region which may be substantially flat, domed, recessed or recessed and reverted.

The closure may be made substantially of steel, aluminium, aluminium alloy, or plastics.

The spokes might extend between the brim and the sidewall with both a radial and a circumferential component and the closure may further comprise lines of weakening that extend from the spokes into the sidewall.

The closure may be configured to allow a part of the sidewall, and optionally at least part of the spokes, to be secured to a neck of the container by crimping.

The brim may terminate at its periphery with a curled edge.

The closure may be dimensioned to close a container having an internal aperture diameter between 20 mm and 50 mm and more preferably of between 30 and 45mm.

The closure may be configured such that, when affixed to a container, the sidewall of the closure exerts a gripping force on the container to resist removal of the closure, and that gripping force is relaxed by rotation of the brim relative to the sidewall. As an option the spokes might comprise a component, which extend radially inward of said sidewall in order to provide features that exert said gripping force.

According to a second aspect of the present invention there is provided a method for attaching a closure according to the first aspect of the invention to a container, wherein the closure is of metal and the container has a circumferentially extending rim provided at or in proximity to an aperture of the container. The method comprises placing the closure over the aperture so that the sidewall extends over the rim and crimping the sidewall against the container to form a seal between the closure and the container. The container may be a beverage can, a metal bottle, and a glass or plastic bottle.

According to a third aspect of the present invention there is provided a method for attaching a closure according to the first aspect of the present invention to a container having a circumferentially extending rim provided at or in proximity to an aperture of the container. The method comprises placing the closure over the aperture so that the sidewall extends beyond the lip, pressing the closure down onto the container in order to snap the closure over the lip and thereby form a seal between the closure and the container.

According to a fourth aspect of the present invention there is provided a metal container adapted to accommodate a closure according to the first aspect of the present invention, and having a curled aperture with an internal diameter between 20 mm and 50 mm.

According to a fifth aspect of the present invention there is provided a metal container adapted to accommodate a closure according to the first aspect of the present invention, and having a curled aperture with an internal diameter between 30 and 45mm.

Drawings Figure 1 A shows a perspective view of a flat panel closure; Figure 1B shows a cross section of the flat panel closure of Figure 1A; Figure 2A shows a perspective view of a recessed panel closure; Figure 2B shows a cross section of the recessed panel closure of Figure 2A; Figure 3A shows a perspective view of a recessed and reverted metal closure; Figure 3B shows a cross section of the recessed and reverted metal closure of Figure 3A; Figure 4A shows a perspective view of a metal container; Figure 4B shows a cross section of the metal container of Figure 4A; Figure 4C shows a partial enlarged cross section of the metal container of Figure 4A; Figure 5A shows a perspective view of a recessed and reverted metal closure fixed to a metal container; Figure 5B shows a cross section of the closure and container of Figure 5k Figure 5C shows a partial enlarged cross section of the closure and container of Figure 5A; Figure 6A shows a perspective view of a crimping tool arrangement; Figure 6B shows a cross section of the crimping tool arrangement of Figure 6A; Figure 6C shows a partial enlarged cross section of the crimping tool arrangement of Figure 6A before crimping; Figure 6D shows a partial enlarged cross section of the crimping tool arrangement of Figure 6A after crimping; and Figure 7 A shows a schematic plan view of a closure before rotation of the brim; Figure 7 B shows a schematic plan view of the closure following rotation of the brim.

Figure 8A shows a perspective view of an alternative recessed and reverted metal closure; Figure 8B shows a cross section of the alternative recessed and reverted metal closure of Figure 8A; Figure 9A shows a perspective view of a closure shell; Figure 9B shows a cross section of the closure shell of Figure 9A; Figure 10A shows a perspective view of a partly manufactured closure; Figure 10B shows a cross section of the partly manufactured closure of Figure 10A; Figure 11 shows a plastic closure; Figure 12 is an enlarged partial internal view of the plastic closure of Figure 11;

Detailed Description

A thread-less closure for a container is illustrated in the accompanying Figures, where the closure is identified by reference numeral 1 and the container, where shown, is identified by reference numeral 2. As will be clear from the following discussion, the closure 1 is loosened during operation by twisting its brim relative to the container 2.

Referring to Figure 1A and 1B, there is provided an exemplary closure 1, which comprises a generally flat central panel region 3 adjoining a downwardly dependent and generally cylindrical side wall 4, which is in turn connected to an outer brim 5 by a multiplicity of radially extending spokes 6. The periphery of the cap is curled in on itself to create the brim 5 and to avoid presenting a sharp edge to the user.

It is preferable that the closure 1 should be made of a material identical or similar to that of the container 2 to optimise recycling. For application to an aluminium container, the closure 1 is preferably made of aluminium or an aluminium alloy. The surfaces of closure 1 may be protected with a polymer layer or organic coating and may be decorated to enhance the appearance and provide visual information. It will be appreciated that the closure 1 may of course be made of any other appropriate material such as steel or plastics.

Considering the centre panel 3, a generally flat centre panel is preferred if the closure is to be applied to a rigid (e.g. glass) bottle container 2 having a small aperture. However, the panel may alternatively be domed or recessed. A recessed centre panel 3, as shown in Figure 2A and 2B, is preferred if the closure is to be applied to a less rigid (e.g. aluminium) bottle container 2 having a small aperture. A recessed and reverted centre panel 3, as shown in Figure 3A and 3B, is preferred if the closure 1 is to be applied to a can or bottle having a larger aperture. The recess may be shaped to accommodate a tool to provide radial support during crimping.

Considering further the spokes 6, these extend radially inwardly from the brim 5 and meet the side wall 4. The spokes 6 may form part of the region of the closure that is crimped, although they will generally not extend above that region as the seal might otherwise be compromised. The spokes 6 are configured to provide sufficient structure to hold the brim 5 in place and to allow it to be twisted around the side wall 4. The spokes 6 may be formed by cutting slits in the metal sheet from which the closure is formed.

Figure 4A illustrates a metal container 2 to which the closure is to be affixed. The container comprises a necked region forming an aperture. As will be clear from Figures 4B and 4C, the rim surrounding the aperture is curled to form a lip 10. The lip may have a width of between 1mm and 6mm and more preferably between 1.5mm and 4mm. The container 2 may be any suitable container having an aperture that a closure can be crimped onto, and may contain any product including food-stuffs or beverages.

The container may be a non-threaded metal beverage can or metal bottle having an internal aperture diameter between 20mm and 50mm and more preferably between 28mm and 45mm, and more preferably between 35mm and 45mm.

It is preferable to curl the aperture of the container 2 in two steps to enhance its rigidity: firstly forming a curl of a smaller radius and then a curl of a larger radius, such that the first curl is surrounded by the second curl. Further forming steps may be carried out to stiffen the curl further or to more accurately control or alter the profile or dimensions of the curl.

Figure 5A to 5C illustrate the recessed and reverted closure 1 of Figures 3A and 3B fixed to the container 2 of Figures 4A to 4C. The closure is pressed against the neck of the container 2, beneath the outwardly curled lip 10 of the container, in order to secure the closure in place. The closure will typically be sealed to the neck using a crimping procedure in order to push a crimp region tightly against the neck of the container.

Although not shown in the Figures, a sealing compound such as a polymer may be provided around the inner surface, or a portion of the inner surface, of the closure in order to aid sealing. The sealing compound may also contain substances to enhance the intended contents of the container 2, such as oxygen scavengers for example.

Figures 6A to 6D illustrate further the process for attaching the closure 1 to the container 2. The recessed and reverted closure 1 is first placed over the necked region of the container. A pair of rollers 8 is moved around the side wall 4, exerting a force against the side wall in order to form the crimp. The closure is supported during crimping by placing a tool 9 within the recess (Figure 6C). The rollers 8 orbit the closure 1 and move radially inwards, as shown in Figure 6D. Alternatively, the container 2 and closure 1 may be rotated whilst the roller or rollers are moved radially inwards. During crimping, it is anticipated that the spokes 6 will become taut and the height of the side wall 4 will decrease as its diameter is reduced.

The closure 1 is removed from the container 2 by firstly twisting the brim 5 about the axis of the container. This imparts tension into the spokes 6, which in turn pulls the side wall 4 radially outwards, to enable the closure to then be pushed or pulled upwards off the container 2.

The diagram of Figure 7A and 7B illustrate schematically how tension is generated in the spokes to pull the sidewall radially outwards. Figure 7A shows an arrangement comprising a circle of diameter D1 which represents the rigid brim and a circle of diameter D2 which represents the less-rigid sidewall. The two circles are joined in this example by four exemplary spokes of length L. Figure 7B shows the arrangement after the brim has been rotated relative to the sidewall. In order for the spokes to retain their length L, the diameter of the sidewall is increased from D2 to D3. A mechanical advantage is illustrated by the distance of circumferential movement M1 of the brim relative to the distance of radial movement of the sidewall M2. This mechanical advantage increases the radial force of the spokes on the sidewall in relation to the circumferential force applied by the brim. Movement of the brim in any direction generally perpendicular to the spoke will create tension in the spoke in this way, and it is thus intended that the closure may be removed from the container by any combination or sequence of rotation of the brim in either direction and of lifting or tilting the brim relative to the closure axis.

Preferably the strength of each part of the closure 1 is adapted so that this is easily achieved without the use of any tool. The strength of each part of the closure 1 may be adapted to require a grip and/or a level of force or torque that for example only an adult could be expected to be able to apply. However, if desired for additional security, the closure 1 may be made strong enough to require the use of a tool.

The frictional contact between the closure 1 and the container 2, including that of the seal and from any interference fit inward of the side wall 4, may be adapted to resist rotation of the closure 1 during opening. Additional features, such as lugs for example, may also be provided to prevent such rotation.

If the closure 1 is made of metal, then the strength of each part of the closure may be adapted to require the brim 5 to be twisted more than once in opposing directions to sufficiently release the side wall 4. It is preferable that opening causes sufficient permanent distortion to indicate that the closure has been opened.

The strength of each part of the closure 1 may be adapted to allow the closure 1 to be re-attached to the container 2 after it has been opened. Re-attachment may provide any extent of re-sealing, spillage resistance or intentional ventilation, according to the desired purpose.

Figure 8A and 8B illustrate a modified closure construction according to which the spokes 6 are slightly curved prior to attachment of the closure to a container. The result of crimping the closure around the container neck causes the spokes to become more radially aligned. The edges of the spokes 6 may be twisted slightly up or down to prevent them jamming against one another during opening.

Considering now a manufacturing process for a closure of the type illustrated in Figure 3, i.e. having a recessed and reverted central panel region, it is preferred to manufacture firstly a shell 7 from a blank metal disk, as shown in Figures 9A and 9B, comprising the features of a recessed and reverted centre panel 3 surrounded by an annular profile. The brim 5 is formed by curling the outer wall of the shell 7, preferably by firstly forming a curl of a smaller radius and then a curl of a larger radius, such that the first curl is surrounded by the second curl. Slits are cut in the upper face of the annular profile as required to create the spokes 6, as shown in Figure 10A and 10B. This may be achieved using a multiple shearing tool. Alternatively, the slits may be cut using some other process such as laser cutting. The side wall 4 is preferably formed by drawing the upper face down, without altering the centre panel 3. Forming the side wall 4 in this way enables the inner ends of the slits, and hence the inner ends of the spokes 6 to turn upwards to join vertically and become part of the lower end of the side wall 4. The steps of forming the rim curls may be combined with the steps of cutting the slits and forming the side wall 4, or they may be carried out separately.

Figure 11 illustrates an alternative closure 1 that is produced by injection moulding of a plastics material. Such a closure may be used with a container having a rim formed around its opening such that the closure is pressed and snapped over the rim. With this closure, the side wall 4 is segmented, and the profiles of the segments are configured to provide a fulcrum, thereby allowing the spokes 6 to partially lever the crimp out of engagement with the container. Such a plastic closure may simply be pushed axially down over the top of a container 6, with or without the use of a roller.

Figure 12 shows an enlarged internal detail of the plastics closure of Figure 11 and from which it can be seen that the central panel 3 is connected via the sidewall 4 to a multiplicity of downwardly dependent legs 11. The downwardly dependent legs are joined to circumferentially directed arms 12. Engagement features 13 are positioned at the farthest end of the arms 12 and are directed radially inwards to retain the closure on a container. Spokes 6 are also positioned at the ends of the arms 12 and are directed radially outwards. The outermost ends of the spokes are connected flexibly to the brim 5. When secure to a container, the engagement features exert a force beneath and against the rim of the closure, thereby resisting rotation of the closure. Twisting the brim 5 in the direction of Arrow A pulls on the spokes and disengages the engagement features 13 by moving them radially outward in the direction of Arrow C, whilst bending the arm 12 and twisting the leg 11 in the direction indicated by Arrow B. Once sufficient rotational force has been exerted on the brim by the user, the engagement feature will be pulled outwardly from underneath the rim of the container such that the user can then pull the closure off the container.

It will be appreciated by the person of skill in the art that various modifications may be made to the above described embodiments without departing from the scope of the invention. For example, if the closure is made of moulded plastic, it may be preferable to provide additional features, for example that tear during twisting, to indicate that the closure has been opened.

Considering further modifications to the closure, the closure may have a fluted side wall 4. In this case, the process of affixing the closure to a container may involve pressing the sidewall inwards by moving an annular tool axially downwards, in the same manner as a "crown" closure is applied to a bottle. When cutting the slits, it may be desirable to shear the metal so as to distort the cut edges to form twists or louvers. Drawing the upper face down to form the side wall 4 may flatten these twists, but residual stresses and strains will enable them to partially regenerate during subsequent operations including crimping and opening.

The side wall 4 of the closure 1 may be intentionally weakened along lines extending from the slits between the spokes 6, for example by scoring or shearing partly through the metal. In this way the spokes extend up into the side wall 4 by way of the scores. Twisting of the brim 5 and hence of the spokes 6 will cause the weakened lines to tear, assisting loosening of the closures and reducing the force required to open.

Claims

CLAIMS: 1. A closure for a container, the closure comprising an end panel, a sidewall depending from the end panel for extending circumferentially around the container, and a brim which is located radially outward of the sidewall and which is connected to the sidewall by a multiplicity of spokes, the spokes extending with a radial component between the sidewall and the brim such that movement of the brim relative to the sidewall creates a radially outward pulling force to loosen the grip of the closure on the container during opening.
2. A closure according to claim 1, wherein the brim is configured such that, when the closure is affixed to a container, rotation of the brim about the container is substantially not impeded by the container other than by forces exerted on the brim by the spokes.
3. A closure according to claim 1 or 2 and configured such that, when affixed to a container, rotation of the brim about the container permanently distorts or tears a part of the closure to provide evidence of such rotation.
4. A closure according to any one of the preceding claims, wherein the central panel region is one of: substantially flat; domed; recessed; and recessed and reverted.
5. A closure according to any one of the preceding claims and being substantially of steel, aluminium, aluminium alloy, or plastics.
6. A closure according to any one of the preceding claims, wherein spokes extend between the brim and the sidewall with both a radial and a circumferential component.
7. A closure according to any one of the preceding claims and comprising lines of weakening that extend from the spokes into the side wall.
8. A closure according to any one of the preceding claims and being configured to allow a part of the side wall, and optionally at least part of the spokes, to be secured to a neck of the container by crimping.
9. A closure according to any one of the preceding claims, wherein the brim is terminated at its periphery with a curled edge.
10. A closure according to any one of the preceding claims and being dimensioned to close a container having an internal aperture diameter between 20 mm and 50 mm and more preferably of between 30 and 45mm.
11. A closure according to any one of the preceding claims and configured such that, when affixed to a container, the sidewall of the closure exerts a gripping force on the container to resist removal of the closure, and that gripping force is relaxed by rotation of the brim relative to the sidewall.
12. A closure according to any one of claims 1 to 11, wherein said spokes comprise a component which extends radially inward of said sidewall in order to provide features that exert a gripping force on a container to resist removal of the closure, and wherein that gripping force is relaxed by rotation of the brim relative to the sidewall.
13. A method of attaching the closure of any one of the preceding claims to a container, wherein the closure is of metal and the container has a circumferentially extending rim provided at or in proximity to an aperture of the container, the method comprising: placing the closure over the aperture so that the sidewall extends over the rim; crimping the sidewall against the container to form a seal between the closure and the container.
14. A method according to claim 13, wherein the container is one of a beverage can, a metal bottle, and a glass or plastic bottle.
15. A method of attaching the closure of any one of claims 1 to 12 to a container, the container having a circumferentially extending rim provided at or in proximity to an aperture of the container, the method comprising: placing the closure over the aperture so that the sidewall extends beyond the lip; pressing the closure down onto the container in order to snap the closure over the lip and thereby form a seal between the closure and the container.
16. A metal container adapted to accommodate the closure of any one of claims 1 to 12 and having a curled aperture with an internal diameter between 20 mm and 50 mm.
17. A metal container adapted to accommodate the closure of any one of claims 1 to 12 and having a curled aperture with an internal diameter between 30 and 45mm.