GB2440525A

GB2440525A - Container and closure assembly having a membrane cutting element in the closure

Info

Publication number: GB2440525A
Application number: GB0615458A
Authority: GB
Inventors: William Hughes; Simon Mellor
Original assignee: Mars Inc
Current assignee: Mars Inc
Priority date: 2006-08-03
Filing date: 2006-08-03
Publication date: 2008-02-06
Also published as: GB0615458D0

Abstract

A container 1 and closure assembly comprising: a container having a neck, a circumferential lip 4 defining an opening at the top of the neck, a neck screw thread 3 on the outside of the neck, and a membrane seal 5 extending across the lip; and a closure 8 comprising: a closure skirt 9 having a closure screw thread 11 on the inside thereof for screwing the closure onto the neck by engagement with the neck screw thread; an opening 15 located above the closure skirt to permit drinking or pouring of liquid through the closure after opening of the membrane seal, and a cutting element 18 for cutting the membrane seal, wherein the cutting element is molded in one piece with the closure skirt and is located inside the closure at a height above the closure screw thread such that, in use, screwing the closure onto a fully engaged position on the container neck causes the cutting element to cut through the membrane seal to open the membrane seal. The closure may be provided with a tamper evident ring 33 that may be linked to the bottom of the skirt 9 by frangible integrally molded bridges 34, whereby the closure skirt can be pushed into the tamper evident ring in telescope fashion as the closure is screwed into the fully engaged position.

Description

CONTAINER AND CLOSURE ASSEMBLY HAVING A MEMBRANE CUTTING

ELEMENT IN THE CLOSURE.

The present invention relates to a container and closure assembly comprising a container neck that is sealed by a membrane of sheet material, and a one-piece closure that is adapted to pierce the membrane when the closure is screwed into a fully secured position on the container neck.

It is known in the packaging art to provide containers having a threaded neck that is sealed with a thin membrane of sheet material. The membrane may be formed of plastic film, metal foil, paper, or it may be a laminate of more than one layer of such materials.

The membrane acts as a barrier to prevent contaminants, including in some cases oxygen, from entering the package. The membrane also prevents leakage of the container contents, and provides a tamper-evident seal for the container. The membrane is sealed onto the container neck by adhesive, or the membrane may comprise a layer of heat-sealable material that enables the membrane to be joined to the package by conventional heat-sealing techniques. A re-sealable internally threaded cap, optionally incorporating a pour spout, is then secured onto the neck. In order to open a container with a sealing membrane, the user must either puncture or remove the membrane. Both processes require complete removal of the threaded cap. If the user tries to remove the membrane manually, it may be difficult to grip. Alternatively, if a user chooses to puncture the membrane, a separate sharp implement is usually required. Even after puncturing the membrane, the punctured pieces of the membrane may need to be manually removed, and will be contaminated with the container contents. There is a risk that pieces of the membrane will fall into the container. Furthermore, in the case of metal foil- containing membranes, the edges of the cut metal foil can be sharp enough to cause injury. Moreover, the forces involved in puncturing or removing the membrane may jostle the contents of the container, which can cause a mess when the container opens.

US-A-6,223,924 and US-A-200425 1276 disclose devices whereby a rotational movement of an internally threaded, specially designed cap is translated by means of cam surfaces or internal threads into a downward movement of a piercing structure. Such devices are relatively complex and may be difficult or expensive to fabricate.

The present invention provides a container and closure assembly comprising: a container having a neck with an opening at the top of the neck, a neck screw thread on the outside of the neck, and a membrane seal extending across the opening at the top of the neck; and a closure comprising: a closure skirt having a closure screw thread on the inside thereof for screwing the closure onto the neck by engagement with the neck screw thread; an opening located above the closure skirt to permit drinking or pouring of liquid through the closure after opening of the membrane seal, and a cutting element for cutting the membrane seal, wherein the cutting clement is molded in one piece with the closure skirt and is located inside the closure at a height above the closure screw thread such that, in use, screwing the closure onto a fully engaged position on the container neck causes the cutting element to cut through the membrane seal to open the membrane seal.

iS The container and container neck may be of conventional design and dimensions. For example the container and optionally also the neck may be formed by blow-molding of thermoplastics such as polyolefins. Alternatively, the neck may be formed by injection molding and the container body may be made by blow molding, for example from polyethylene terephthalate (PET) in known fashion. Suitably, the opening in the top of the is substantially circular.

The membrane seal may be formed of plastic film, metal foil, paper, or it may be a laminate of more than one layer of such materials. In certain embodiments, the membrane is a laminate of a metal foil and one or more plastics layers. The membrane is secured to the top of the container neck by adhesive or by heat-bonding to form a substantially leak-proof seal over the neck.

En a first configuration, the closure is partially screwed onto the container neck to as to retain the closure on the container neck without opening the membrane seal. in this configuration the container and closure can be shipped and stored with the membrane seal intact. The closure may further comprise other tamper-evident features, such as an integral tamper-evident ring, that are undisturbed in the first (storage and shipping) configuration. Opening of the membrane seal can take place immediately before consumption, by screwing the closure down further to the fully secured position on the container neck.

The threads may be substantially continuous helical threads that can be moved from a fully disengaged to the partially engaged position by relative rotation of the container neck and closure by at least about 90 , for example from about 120 to about 720 , typically about 1800 to about 540 . Suitably, the container neck and closure can be moved from the partially engaged position to the fully secured position by a further rotation through about 900 to about 720 , typically a further rotation through about 120 to about 5400, for example about 270 to about 450 .

The cutting element is a projection molded into the closure that projects downwardly at a location radially inwardly of the closure skirt, such that the cutting element is pushed into, and ruptures the sealing membrane as the closure is screwed into the fully secured position on the container neck.

Suitably, the closure comprises an annular base region having a central opening to permit pouring or drinking of the contents of the container through the closure when the closure is retained in the fully secured position on the container neck. The threaded closure skirt suitably projects downwardly from a radially outer edge of the annular base, and the cutting element also suitably projects downwardly from the annular base at a location radially inside the closure skirt. A tubular pour spout or pouring lip may project upwardly from the annular base. The height of the cutting element is selected such that it does not engage with the sealing membrane when the closure is at the intermediate (shipping and storage) position on the neck described above, but so that it does rupture the membrane on further screwing down the closure the fully secured position on the neck.

The cutting element typically has a leading edge that cuts into the membrane as the closure is screwed down on the container neck. Suitably, the cutting element follows a circular path around the membrane as the closure is screwed down on the container neck, so as to cut around a central circular regionof the membrane. The central circular region suitably has a radius substantially equal to, or greater than, the radius of the central opening in the closure.

Suitably, a radially outermost surface of the cutting element is located proximate to the radially innermost surface of the opening in the container neck, whereby the cutting element cuts through the membrane with a scissor (guillotine) action against the radially innermost surface of the top of the neck. This achieves effective cutting without the need for a very sharp cutting edge on the cutting element, and has the added advantage that the largest available area of the membrane is cut away. Suitably the radial distance between the radially outermost surface of the cutting element (which is normally also the leading/cutting edge of the cutting element) and the radially innermost surface of the neck opening in the vicinity of the membrane is less than about 2mm, preferably less than about 1mm, in order to achieve this scissor cutting action.

In certain embodiments, the cutting element is in the form of an arcuate (in plan view) projection depending from the annular base of the closure. The arcuate projection is preferably in the form of a section of a cylindrical tube, with external radius slightly less (e.g 0.1 to 2mm, preferably 0.2 to 1mm less) than the internal diameter of the neck in the vicinity of the membrane, and extending circumferentially from about 30 to about 240 , for example about 60 to about 180 around the closure. As already noted, the arcuate blade functions to cut through the membrane by means of a scissor action with the inside of the neck. Furthermore, the outer surface of the arcuate projection is effective to push the cut edge of the membrane away from the circular aperture. The mean height of the arcuate projection (i.e. the height measured from the base region of the closure) is typically from about 2mm to about 5mm, for example abut 3mm.

Preferably, the threads are configured such that, even in the fully secured position, the cutting element has not cut entirely around any part of the membrane, so that the membrane after cutting is still retained on the container neck and none of the membrane drops into the container, from where it might be consumed by a user. In suitable embodiments the height of the cutting element is selected such that the cutting element has cut through the membrane along a substantially circular path for an angular distance of at least about 180 when the closure is in the fully secured position on the container neck, but preferably not more than about 330 . Preferably, the circular path extends for an angular distance of from about 2700 to about 300 , whereby the membrane is retained on the neck by an uncut section extending about 60 to about 90 around the neck.

Since the membrane is not completely detached from the neck by the cutting element, the membrane after cutting may still obstruct the flow of liquid out of the container or cause irregular flow unless it is kept away from the opening. Accordingly, in certain embodiments, the closure further comprises a sweeper element projecting radially inwardly from the cutting element for sweeping the membrane away from the opening after it has been cut by the cutting element. In the case of foil membranes, the sweeper element permanently deforms the membrane after it has been cut by crushing it towards one side of the opening. The sweepet element suitably extends a radial distance of from about 2mm to about 10mm, for example from about 4mm to about 8mm, inwardly from the cutting edge. These dimensions refer to a typical container neck having a diameter of about 2cm to about 4cm. It will be appreciated that the sweeper element may be larger for larger container necks. The sweeper element may, for example comprise a rib projecting downwardly from the annular base of the closure and extending substantially along a chord of the cutting circle defined by the cutting element and having a first end proximate to the cutting edge of the cutting element. In certain embodiments, the sweeper element may comprise a substantially triangular (in plan view) projection into the cutting circle defined by the cutting element.

Suitably, the closure further comprises one or more circumferential sealing surfaces for engagement with one or more circumferential sealing surfaces on the container neck to prevent leakage of liquid from the container between the container neck and the closure when the closure is in the fully secured position on the container neck. For example, the circumferential sealing surface on the closure may be provided by a lower annular surface of the annular base region of the closure. The circumferential sealing surface on the container neck may comprise a circumferential lip of the container. There may be further circumferential sealing ribs or inserts (liners) in the closure to improve the sealing between the closure and the container neck.

Suitably, the container and closure assembly according to the present invention further comprises an overcap for sealing the opening in the closure after the membrane seal has been opened. In this way the assembly can be resealed after the membrane has been ruptured, while the closure is in the filly secured position on the container neck. The overcap may be of any suitable design, for example it may comprise an internal thread and/or snap fittings for engagement with complementary fittings on the closure. In certain embodiments, the overcap is a hinged cap formed in one piece with the closure.

Suitably, the closure in the assembly according to the present invention further comprises a tamper-evident ring attached to the closure skirt by frangible bridges, and the container neck comprises a circumferential projection against which the tamper-evident ring is driven to break the frangible bridges when the closure is screwed into the fully secured position on the container neck. This configuration of tamper-evident ring provides the advantage that a separate step of removing the tamper-evident ring from the neck of the container, which can be problematical with existing closure formats, is avoided. Suitably, the tamper-evident ring and frangible bridges are molded in one piece with the closure.

In certain embodiments, the tamper-evident ring has an internal diameter greater than or equal to the outside diameter of the closure skirt adjacent to the tamper-evident ring, whereby a lower region of the closure skirt is pushed inside the tamper-evident ring when the closure is screwed onto the fully secured position on the container neck.

Suitably, in these embodiments the tamper-evident ring further comprises one or more inwardly projecting retaining elements, for example projecting bosses, for retaining the tamper-evident ring on the lower region of the closure skirt following separation of the frangible bridges.

It can thus be seen that the present invention provides a convenient and hygienic way to open membrane-sealed containers, simply by screwing down a closure cap that is already provided on the neck. The contents of the container can then conveniently be dispensed directly through the cap. It is a particular advantage of the present invention that the closure skirt, including the cuttizig element and the sweeper element (where present) are molded in one piece at low cost. The tamper-evident ring (where present) is also molded in one piece with the closure. In certain embodiments, the overcap is also molded in one piece with the closure. Typically, the closure is molded from thermoplastic material, such as polypropylene or polyethylene, for example by injection molding.

An embodiment of the present invention wilt now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a side elevation view of a container and closure assembly, with the closure in the intermediate (storage and shipping) position on the container neck; Figure 2 shows a bottom plan view of the closure in the embodiment of Fig. 1; Figure 3 shows a side elevation view of the assembly of Fig. 1, with the closure screwed down into the fully secured positionon the container neck, and with the overcap of the closure in the open position; Figure 4 shows a longitudinal cross section through the closure and neck region of the assembly shown in Fig. I, with the closure in the intermediate (storage and shipping) configuration, and with the overcap in the open position; and Figure 5 shows a longitudinal cross section through the closure and neck region of the assembly shown in Fig.3, with the closure in the fully secured configuration on the container neck, and with the overcap in the open position Referring to Figs. I to 5, the assembly according to this embodiment of the invention comprises a container I having a container body 2 and a neck, both formed by blow molding (in alternative embodiments the neck could be formed by injection molding, in known fashion). The container may for example be filled with a beverage, for example a dairy-based drink. The container neck has a two-start, continuous helical thread 3 on the outer cylindrical surface thereof. At the top of the neck is a lip 4 surrounding the circular opening at the top of the container neck. An internal, circular edge I 7 of the lip 4 defines the opening in the neck. A plastics-coated foil membrane 5 is sealed across the opening by heat bonding in conventional fashion, so as to form an oxygen-and microorganism-impermeable seal across the opening. Finally, a circumferential flange 6 extends around the container neck below the thread 3 and projecting radially beyond the thread 3. The flange 6 has two functions. Firstly, the container can be gripped below the flange by a suitable clamp (not shown) during filling and sealing of the container 1.

Secondly, the flange 6 provides an abutment surface for the tamper-evident ring on the closure, as described further below.

The assembly according to this embodiment of the invention further comprises a closure 8 formed from polypropylene by injection molding in one piece, and shown in more detail in Fig. 2. The closure 8 comprises a closure skirt 9 having a longitudinally ribbed outer surface 10 to assist gripping of the closure during rotation thereof. The inner surface of the closure 9 is provided with a two-start, continuous helical thread 11 that is complementary to the thread 3 on the container neck, whereby the closure 8 can be moved from a substantially disengaged position to a substantially fully engaged position on the container neck by a single smooth rotation through about 2 revolutions (720 degrees). -The closure skirt 9 depends from an annular base region 14 of the closure. The annular base region has a central circular aperture 15 that allows drinking or pouring of the liquid from inside the container through the closure 8 after the membrane seal 5 has been opened. A cylindrical pouring lip 16 projects upwardly from the base region 14 of the closure 8 to assist pouring or drinking from the container when the closure is attached thereto. It will be appreciated that in this and other embodiments the pouring lip 16 may be replaced by a longer pouring or drinking spout, optionally of smaller diameter than the pouring lip shown in this embodiment.

The closure 8 further comprises a cutting element 18 in the form of an arcuate blade projecting downwardly from the base region 14 of the closure. The cutting element is in the form of a section of a circular tube of radial thickness about 1mm. It extends to a height below the base region 14 of about 3mm, and for approximately 160 around the circumference of the circular aperture 15 in the base region 14 of the closure. The leading edge 19 of the cutting element 18 functions as a cutting edge to cut through the foil membrane seal in use. The height of the cutting element 18 is selected so that the cutting element is just clear of the membrane seal when the closure is screwed approximately half-way onto the container neck (i.e. at about 300 from the fully secured position), as shown in Fig. 4, but such that the cutting element penetrates the foil seal for approximately the last 300 of travel of the closure as it is screwed onto the fully secured position on the container neck, as shown in Fig. 5. That is to say, the membrane is retained on the neck by an uncut section of radial extent about 600 after the closure is fully screwed down on the container neck.

An important feature of the cutting action is that the radially outermost surface of the cutting element 18 is proximate to the radially innermost surface 17 of the container neck, whereby the cutting element cuts through the membrane 5 with a scissor (guillotine) action against the innermost surface 17. This achieves effective cutting without the need for a very sharp cutting edge, and has the added advantage that the largest available area of the membrane is cut away. As already noted, the cutting element extends approximately 160 around the circumference of the circular aperture 15 in the base region 14 of the closure. This extension of the cutting element is effective to push the outside cut edge of the membrane away from the circular aperture 15.

The closure 8 further comprises a sweeper element 20 projecting inwardly from the leading edge 19 of the cutting element 18, generally along a portion of a chord of the circular aperture 15. The sweeper element 20 has generally the same height as the cutting element 18, and functions to clear the membrane away from the aperture 15 after it has been cut by the cutting element 18. The inner end 21 of the sweeper element 20 is joined to the cutting element 18 at a location 22 behind the leading edge 19 by means of support rib 23. The support rib 23 provides stability to the sweeper element 21 in use, and also assists in molding of the element.

The lower surface of the annular base region 14 of the closure 8 comprises an annular sealing surface 25 intermediate the closure skirt 9 and the cutting element 18. An annular sealing rib 24 of substantially triangular cross-section projects downwardly from the surface 25. When the closure 8 is on the fully secured position on the container neck as shown in Fig. 5, the lip 4 of the container neck abuts against the sealing rib 24 and the sealing surface 25 to provide a seal that prevents leakage of liquid from inside the container between the neck and the closure skirt.

The closure 8 further comprises an overcap.27 formed in one piece with the remainder of the closure and hinged thereto by integral hinge 28. The overcap 27 includes a base 29, l0 an outer skirt 30, and an inner cylindrical sealing plug 31 that forms an interference-type seal inside pouring lip 16 of the closure to seal the closure when the outer skirt 30 of the overcap is pressed down Onto the annular base region 14 of the closure. In this way, the overcap enables the assembly to be resealed after opening of the membrane seal.

S

The closure 8 further comprises a tamper-evident ring 33 that is linked to the bottom of the closure skirt 9 by frangible integrally molded bridges 34. The inside diameter of the tamper-evident ring is very slightly greater than the outside diameter of the bottom of the closure skirt 9, whereby the closure skirt can be pushed into the tamper-evident ring in telescope fashion as the closure is screwed into the filly secured position. Internal projections in the form of four, equally radially spaced bosses 35 are provided on the tamper-evident ring to retain the ringon the outside of the closure skirt alter the ring has been pushed over the skirt in this way. The internal diameter of the tamper-evident ring is less than the diameter of flange 6 on the container neck, whereby the tamper-evident ring 33 abuts against the flange 6 as the closure is screwed onto the neck.

In use, the container I is filled with a flowable material such as a beverage, a sauce, a granulate or a powder. The container is then sealed by application of the membrane foil seal 5, in conventional fashion. The container and contents may then be heat treated to render the contents shelf-stable. The closure 8 is then screwed onto the neck by relative rotation of the container and neck through about 300 . This secures the closure on the neck in an intermediate configuration shown in Fig. 4, wherein the closure is securely retained on the neck but the cutting element 18 does not rupture the sealing membrane.

The bottom edge of the tamper-evident ring 33 abuts against flange 6 on the neck in this configuration, but the frangible bridges 34 remain intact. The container in this configuration can be shipped, stored, and sold to the end user with the membrane seal intact.

In order to consume the beverage, a user further rotates the closure on the neck until a fully secured position of the closure on the neck is reached. The further rotation of the closure initially pushes the bottom of the closure skirt into the interior of the tamper-evident ring, which is held fixed by abutment against the flange 6 on the container neck.

The frangible bridges 34 between the tamper evident ring and the skirt are thereby broken after about 900 of rotation from the storage position. Further rotation of the closure on the neck causes the cutting element 18 to cut through the sealing membrane with a scissor action along a circular path adjacent to the inside edge 17 of the container lip 4. The radius of the circular path is substantially equal to the radius of the circular opening in the neck. The sweeper element pushes the cut membrane away from the opening, thereby allowing free passage of the container contents through the opening.

At the fully secured position shown in Fig. 5, the lip 4 of the container abuts against the annular sealing rib 24 and the sealing surface 25 of the closure, thereby forming a seal between the lip 4 and the closure and blocking further rotation of the closure on the neck. The tamper-evident ring is held on the skirt by the engagement between the retaining elements 35 on the tamper-evident ring 33 and the outer surface of the skirt.

The membrane has been cut along a circular path of about 3000, leaving a sector attached to the lip to retain the membrane on the lip so that it does not drop into the container. The contents of the container can then be consumed or poured through the opening in the base region of the closure. The overcap can be used to reseal the closure if desired.

The above embodiment has been described by way of example only. Many other embodiments fatting within the scope of the accompanying claims will be apparent to the skilled reader.

Claims

CLAIMS

1. A container and closure assembly comprising: a container having a neck, a circumferential lip defining an opening at the top of the neck, a neck screw thread on the outside of the neck, and a membrane seal extending across the lip; and a closure comprising: a closure skirt having a closure screw thread on the inside thereof for screwing the closure onto the neck by engagement with the neck screw thread; an opening located above the closure skirt to permit drinking or pouring of liquid through the closure after opening of the membrane seal, and a cutting element for cutting the membrane seal, wherein the cutting element is molded in one piece with the closure skirt and is located inside the closure at a height above the closure screw thread such that, in use, screwing the closure onto a fully engaged position on the container neck causes the cutting element to cut through the membrane seal to open the membrane seal.

2. A container and closure assembly according to claim 1, wherein a radially outermost surface of the cutting element is located proximate to a radially innermost surface of the opening at the top of the neck, whereby the cutting element cuts through the membrane with a scissor (guillotine) action against the neck.

3. A container and closure assembly according to any preceding claim, wherein the closure comprises an annular base region, the closure skirt extends downwardly from an outer edge of the base region, the opening extends through the center of the base region, and the cutting element projects downwardly from the base region radially inside the closure skirt.

4. A container and closure assembly according to claim 3, wherein the base region of the closure comprises an annular sealing surface for forming a seal against the lip of the container neck when the closure is in the fully secured position on the container neck.

5. A container and closure assembly according to claim 3 or 4, wherein the cutting element is in the form of a section of a cylindrical tube projecting downwardly from the base region of the closure, such that the outer radius of the tubular cutting element is slightly less than the internal diameter of the neck opening.

6. A container and closure assembly according any preceding claim, wherein the threads and cutting element are configured such that even in the fully secured position the cutting element has not cut entirely around any part of the membrane, so that the membrane is still retained on the container neck when the closure is in the fully secured position.

7. A container and closure assethbly according to any preceding claim, wherein the closure further comprises a sweeper element for sweeping the membrane away from the opening after it has been cut by the cutting element.

8. A container and closure assembly according to any preceding claim, wherein the closure further comprises a tamper-evident ring attached to the closure skirt by frangible bridges, and the container neck comprises a circumferential flange against the top of which the tamper-evident ring is driven to break the frangible bridges when the closure is screwed into the fully secured position on the container neck, and wherein the tamper-evident ring has an internal diameter greater than or equal to the outside diameter of the closure skirt adjacent to the tamper-evident ring, whereby a lower region of the closure skirt is pushed into the tamper-evident ring when the closure is screwed onto the fully secured position on the container neck.

9. A container and closure assembly according to claim 8, wherein the tamper-evident ring further comprises one or more inwardly projecting retaining elements for retaining the tamper-evident ring on said lower region of the closure skirt following separation of the frangible bridges.

10. A container and closure assembly according to any preceding claim, wherein the closure is partially screwed onto the container neck so as to retain the closure on the container neck without opening the membrane seal.

11. A container and closure assembly according to any preceding claim, further comprising an overcap for sealing the opening in the closure after the membrane seal has been opened.

12. A container and closure assembly according to claim 11, wherein the overcap is a hinged cap molded in one piece with the closure.