AU2019204507A1 - Improvements in or related to tamper-evident caps and moulds therefor - Google Patents

Abstract

The invention provides a tamper-evident cap assembly for use in sealing a container having a neck, a thread on the neck and a protrusion arranged below the thread. The assembly includes a top, a tubular skirt depending from the top and a band connected to 5 the skirt by a number of frangible bridges. The skirt has a thread on its inner surface which cooperates with the thread of the neck to seal the container. The band has a number of inwardly-pointing protrusions arranged on its inner surface to engage the protrusion of the container, preventing the band from separating from the container. The thread of the skirt is interrupted at predetermined intervals along its length so as to 10 define substantially non-raised portions of the inner surface of the skirt. The protrusions of the band are substantially aligned with the substantially non-raised portions when the band is connected to the skirt. The invention also provides moulds for producing the cap. Figure 1 Figure 2

Description

IMPROVEMENTS IN OR RELATED TO TAMPER-EVIDENT CAPS AND MOULDS THEREFOR

FIELD OF INVENTION

The present invention relates to caps for containers and moulds therefor and in particular 5 to tamper-evident caps.

BACKGROUND

It is common for containers, particularly those with contents for human consumption, to have a cap which indicates whether the container has been opened.

One method of indicating this is to include a number of frangible bridges linking a cap body and a band. As the cap body is urged apart from the band (for example, by rotating the cap, if threaded, about the neck of a bottle), the bridges break. By examining whether the bridges have been broken, it is clear whether the container has been opened. The band may be provided with teeth which act against the wall of the container as the cap is rotated to more readily facilitate separation of the cap from the band.

It is typical for such caps to be manufactured by moulding a suitable plastic material. A core mould and a cavity mould are used together to define a hollow having the particular shape for the cap. A thermoplastic material is injected into the hollow, which, once cooled, forms the cap. To form a thread inside a cap, the mould typically includes hollows such that the plastic of the cap expands to fill the shape of the hollow, thereby forming a raised thread. Once formed, the core mould is removed. However, in doing so, the teeth of the band typically need to pass over the hollows used for forming the thread. This may cause the teeth to become stuck in the hollows, possibly damaging the teeth.

One solution is to reduce the distance that the teeth protrude from the band. However this may lead to insufficient engagement between the teeth and the protrusions on the neck of the bottle, making it difficult for a user to break the bridge and open the container.

OBJECT OF INVENTION

It is an object of the invention to overcome one or more of the disadvantages of the prior art, or to at least provide the public with a useful choice.

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STATEMENTS OF INVENTION

In a first aspect, there is provided a tamper-evident cap assembly for use in sealing a container, the container including a neck, the neck including a thread on the outer surface thereof and a circumferential protrusion arranged below the thread, the assembly including:

a top;

a tubular skirt depending from the top, the skirt including a thread on the inner surface thereof, the thread being adapted to cooperate with the thread of the neck to seal the container; and a band connected to the skirt by a number of frangible bridges, the band including a number of inwardly-pointing protrusions arranged on the inner surface thereof adapted to engage the circumferential protrusion of the container, thereby preventing the band from separating from the container;

wherein, the thread of the skirt is interrupted at predetermined preferably regular intervals along its length so as to define substantially non-raised portions of the inner surface of the skirt, and wherein the protrusions of the band are substantially aligned with the substantially non-raised portions when the band is connected to the skirt.

In a further aspect, there is provided a mould core for producing the assembly of the first 20 aspect.

Preferably, the mould core includes:

top forming means for forming a top of the assembly;

skirt forming means for forming a tubular skirt depending from the top;

thread forming means adapted to form a thread on the inner surface of the skirt;

band forming means for forming a band connected to the skirt by a number of frangible bridges and including a number of inwardly-pointing protrusions arranged on the inner surface thereof;

wherein, the thread forming means includes a number of substantially non-raised portions so as to form the thread so that the thread is interrupted at regular intervals along its length, the protrusions being substantially aligned with the substantially non-raised portions such that, in use, when ejecting the assembly

2019204507 26 Jun 2019 from the mould core, the protrusions move along the substantially non-raised portions.

In a further aspect, there is provided a cap assembly manufactured using the mould core of the second aspect.

Preferred embodiments of the invention are set out in the dependent claims.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements and features, and where specific integers are mentioned herein which have known equivalents in the art to 10 which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF FIGURES

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 shows a front view of a cap assembly of one embodiment of the present invention;

Figure 2 shows a perspective view from above of the cap assembly of Figure 1;

Figure 3 shows a perspective view from below of the cap assembly of Figure 1;

Figure 4a shows a bottom view of a first part of the cap assembly of Figure 1;

Figure 4b shows a plan view of a second part of the cap assembly of Figure 1;

Figure 5 shows a cross-section view along line A-A of the cap assembly of Figure 1;

Figure 6 shows a cross-section view along line B-B of the cap assembly of Figure 5;

Figure 7a shows details of a bridge from a front view of the cap assembly of Figure 1;

Figure 7b shows details of a bridge from a side view of the cap assembly of Figure 1;

Figure 7c shows details of a protrusion of the band of the cap assembly of Figure 1;

Figure 8 shows a front view of the cap assembly shown in Figure 1 connected to a container;

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Figure 9 shows a cross-section view along line C-C of the cap assembly and bottle shown in Figure 8;

Figure 10 shows a front view of a core mould for use in manufacturing the cap assembly of Figure 1;

Figure 11 shows a perspective view from above of the core mould of Figure 10;

Figure 12 shows a front view of a cavity mould for use in manufacturing the cap assembly of Figure 1;

Figure 13 shows a perspective view from above of the cavity mould of Figure 12;

Figure 14 shows a top view of the cavity mould of Figure 12; and

Figure 15 shows a cross-section view along line D-D of the cavity mould of Figure 12.

DETAILED DESCRIPTION

Referring to Figures 1 to 9, there is shown a cap assembly 100 including a top 102. Top 102 is shown with a dimple 104 located substantially in the centre of the upper surface of top 102. Dimple 104 is often an artefact of the manufacturing process of assembly 100, 15 and may not necessarily be present. The underside of top 102 may show information about assembly 100, such as manufacturer name 106a, model number 106b or material code 106c. This information may be printed, embossed, or in any other suitable form, as will be clear to those skilled in the art.

A tubular skirt 110 depends from top 102, which together form the cap body. Skirt 110 20 may be adapted to increase the grip a user may put on the skirt. This may include a number of splines 112 arranged around the outer surface of skirt 110.

It will be appreciated that cap assembly 100, including top 102 and tubular skirt 110, may be formed integrally, and so the term assembly should be construed as including such an embodiment.

A thread 114 is arranged around the inner surface of skirt 110. Thread 114 may be a multi-start thread, such as a triple-start thread, and may have a substantially steep helical angle. Either or both of these features serve to allow the cap to move downward along a cooperating thread with reduced rotational movement. As is common in the art, thread 114 may be a right-hand thread. In the embodiment shown, thread 114 is composed of a number of raised parts which are interrupted at regular intervals, thereby defining substantially non-raised sections 116.

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A band 118 is connected to skirt 110 by a number of frangible bridges 120. Bridges 120 are adapted so that they break when a pre-determined amount of force is used to rotate the cap body, with band 118 remaining substantially stationary, thereby dividing the assembly into a separate cap body and band. The pre-determined amount of force may be chosen to enable an ordinary user (a person or machine, depending on the application) to break the bridges without undue exertion. The increased angle of thread pitch of preferred embodiments increases the rate of the parting of the tubular skirt 110 and the band 118. This results in a cleaner break of bridges 120, as the plastic has less time to potentially stretch and orientate and thus strengthen. In a preferred embodiment, the cap body has a diameter of about 52.5 mm. When connected to band 118 having a height of about 4.95 mm to about 6.5 mm, the cap has total height of about 24.2 mm.

The outer face of each bridge 120 is shown as being trapezoidal, having a shorter side and a longer side being substantially parallel thereto. The shorter side is connected to the bottom edge of skirt 110 and the longer side is connected to band 118.

In a preferred embodiment, the shorter side is about 0.5 mm, and the longer side substantially longer, whereby the two other sides are at an angle of about 60° relative to each other. The outer face is angled about 22.5° from the inner face of bridge 120. The part of skirt 110 connected to bridge 120 may be about 0.4 mm deep

While a trapezoidal shape has a particular advantage in that the smaller connection to skirt 110 compared to band 118 typically lends itself to breaking at the former connection point, it will be appreciated that other shapes may be used without departing from the inventive concept.

For the avoidance of doubt, the term connected as used herein should be construed to include integral forming. For example, bridges 120 may be formed integrally with band 25 118 and/or skirt 110.

In the embodiment shown, band 118 may be castellated to include raised portions 122 and lower portions 124. Raised portions 122 may have the shape of a quadrilateral semifrustum (being half of a quadrilateral frustum, having one side with a profile of a trapezium and the opposing side being substantially perpendicular to the top and bottom faces). Bridges 120 may be located on the upper edge of raised portions 122.

Along the inner surface of band 118, there are a number of inwardly-pointing protrusions 126. Protrusions 126 may be shaped as a quadrilateral semi-frustum, and in some embodiments, protrusions 126 taper, having a greater extent of protrusion near the top and a lesser extent near the bottom.

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Preferably, protrusions 126 are aligned with non-raised sections 116 when top 102 is connected to band 118, and may be more specifically located on the lower portions 124 of a castellated band 118.

In a preferred embodiment, protrusions 126 have a height of about 3 mm and protrude from the inner surface of band 118 by approximately 2 mm near the top and approximately 1 mm near the bottom, with the angle of tapering being about 27.88°.

Referring now to Figure 7, assembly 100 is adapted for use with a container 128, the container 128 having a neck 130. The neck 130 includes a thread 132 on the outer surface thereof and a circumferential outwardly-projecting protrusion 134 arranged below the 10 thread 132. The protrusion 134 may be continuous or separated into discrete parts.

In use, assembly 100 will be located around the neck 130 of the container 128 so as to seal the open end thereof. The tapering of the protrusions 126 may enable the band to be slipped over protrusion in a first direction, but resists movement in a second direction.

When a user wishes to unseal the container, the cap body is rotated in the appropriate direction (that is, anti-clockwise for a right-hand thread). Protrusions 126 will engage with protrusion 134 to cause the cap body to urge apart from the band 118, the band 118 being prevented from moving longitudinally with respect to the container. Thus, the rotational force on the cap body causes bridges 120 to break, allowing the cap body to be removed from the container, while band 118 remains around the neck of the container.

One effect of this is that it will be evident to a user whether the container has been opened since manufacture, as even if the cap body is replaced, band 118 remains separate.

Referring now to Figures 10 and 11, there is shown a core mould 200 for use in manufacturing assembly 100. Core mould 200 includes top forming means 202 for 25 forming the inner face of top 102, skirt forming means 204 for forming the inner face of skirt 110, thread forming means 206 for forming thread 114, band forming means 208 for forming band 118 and a base 210 to connect core mould 200 to a moulding machine or the like.

The thread forming means 206 includes a number of substantially non-depressed 30 portions 214 to interrupt thread 114, thereby forming substantially non-raised sections

116.

Core mould 200 may further include an aperture 212, through which an ejector can pass to assist in holding assembly 100 in place as core mould 200 is removed.

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Referring now to Figures 12 to 15, there is shown a cavity mould 300 for use with core mould 200 in manufacturing assembly 100. Cavity mould 300 includes a top forming means 302 for forming the outer face of top 102 and skirt forming means 304 for forming the outer face of skirt 304. Cavity mould 300 may also include an aperture 306.

In use, core mould 200 and cavity mould 300 are connected together, so as to substantially define an inner hollow. Injection 308 is arranged to inject a thermoplastic material through aperture 306 into the hollow. The material then cools, forming assembly 100. The core mould can then be removed from assembly 100.

Because the substantially non-raised sections 116 of the core mould are substantially aligned with the protrusions 126 when the assembly is in its moulded form (as shown in Figures 1 to 3), they are able to move smoothly over the surfaces of the mould, and do not get trapped in hollows of the thread forming means as the cap assembly and the mould are separated. Thus, the angular extent of the protrusions 126 is preferably less or substantially equal to than that of non-raised sections 116 to reduce interference between the core mould and the assembly 100. This enables protrusions 126 to extend further inwardly than they would otherwise, which increases engagement with the protrusion or the container.

Further, the interrupted thread alleviates the radial pressure on the assembly 100 that would normally occur as the mould core is removed. This reduces the risk that thread 114 20 is distorted or torn as the mould core is removed.

The foregoing description of the invention includes preferred forms thereof. It will be appreciated that modifications may be made to the preferred forms without departing from the spirit and scope of the invention.

The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

Claims (17)

1. A tamper-evident cap assembly for use in sealing a container, the container including a neck, the neck including a thread on the outer surface thereof and a circumferential protrusion arranged below the thread, the assembly including:

a top;

a tubular skirt depending from the top, the skirt including a thread on the inner surface thereof, the thread being adapted to cooperate with the thread of the neck to seal the container; and a band connected to the skirt by a number of frangible bridges, the band including a number of inwardly-pointing protrusions arranged on the inner surface thereof adapted to engage the circumferential protrusion of the container, thereby preventing the band from separating from the container;

wherein, the thread of the skirt is interrupted at predetermined intervals along its length so as to define substantially non-raised portions of the inner surface of the skirt, and wherein the protrusions of the band are substantially aligned with the substantially non-raised portions when the band is connected to the skirt.

2. The assembly of claim 1, wherein an outer face of the bridges is trapezoidal having a shorter side and a longer side substantially parallel, the shorter side being connected to the skirt, the longer side being connected to the band.

3. The assembly of claim 2, wherein the shorter side is about 0.5 mm wide.

4. The assembly of any one of claims 1 to 3, wherein the band is castellated, having raised portions and lower portions; the bridges being on the raised portions.

5. The assembly of claim 4, wherein the protrusions are provided on the lower portions.

6. The assembly of any one of claims 1 to 5, wherein the protrusions have substantially the shape of a quadrilateral semi-frustum.

7. The assembly of any one of claims 1 to 6, wherein the skirt thread has a substantially steep helical angle.

8. The assembly of any one of claims 1 to 7, wherein the skirt thread is a triple-start thread.

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9. The assembly of any one of claims 1 to 8, wherein the assembly is made of polypropylene.

10. A mould core for producing the assembly of any one of claims 1 to 9.

11. The mould core of claim 10, including:

5 top forming means for forming a top of the assembly;

skirt forming means for forming a tubular skirt depending from the top;

thread forming means adapted to form a thread on the inner surface of the skirt;

band forming means for forming a band connected to the skirt by a number of frangible bridges and including a number of inwardly-pointing protrusions 10 arranged on the inner surface thereof;

wherein, the thread forming means includes a number of substantially non-raised portions so as to form the thread so that the thread is interrupted at regular intervals along its length, the protrusions being substantially aligned with the substantially non-raised portions such that, in use, when ejecting the assembly 15 from the mould core, the protrusions move along the substantially non-raised portions.

12. A cap assembly manufactured using the mould core of claim 10 or 11.

13. A mould cavity for producing the assembly of claim 1.

14. A cap assembly manufactured using the mould cavity of claim 13.

20

15. A set of parts, including:

one or more of the mould core of any claim 10 or 11; and one or more of the mould cavity of claim 13.

16. A cap assembly substantially as herein described with reference to Figures 1 to 9.

17. A mould core substantially as herein described with reference to Figure 10 and 11.

25 18. A mould cavity substantially as herein described with reference to Figures 12 to 15.