NZ539754A - Tamper proof and tamper evident cap for aerosol can - Google Patents

Abstract

A tamper evident cap for an aerosol can has a pair of concentric can engagement "rings" 9 and 10, ring 9 on the distal base end of the cap and ring 10 on the top end of the cap. The distal portion and the top portion are joined by a frangible portion 5. The cap is fitted to the top of the can with both of the rings engaging respective formations on the can. When the top end of the cap is removed from the base portion by breaking the frangible portion 5, the base portion remains attached to the can by engagement of the ring 9 and the top portion may be refitted to the can using the ring 10 of the top portion. Fig. 7 shows a variation of the arrangement.

Description

53^ Patents Form #5 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL # : 539754 DATED : 02 May 2005 TITLE : TAMPER EVIDENT OR TAMPER PROOF CAP We, WHURL PLASTICS LIMITED Address: Cnr Kaka & Tui Sts, Otahuhu, Auckland, New Zealand Nationality: A New Zealand company do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: 190700NZ_Cap_20060424_1338_AEELdoc - 1 FEE CODE 1050 intellectual property office of n.z. -1 MAY 2008 FIELD OF INVENTION This invention relates to improvements to caps in particular but not exclusively to caps used with aerosol cans.

BACKGROUND ART KNOWN TO THE APPLICANT Containers generally come in two forms, those that require some form of lid or cap and those that do not. Those that require or otherwise utilise a lid or cap, tend to do so to allow ready access to the contents of the container whilst also providing a means of protecting or preserving the contents of the container from the outside world. However, some containers, for example aerosol cans, and "ball deodorants", tend to use caps to prevent or reduce to a minimum, any unwanted discharge or loss of the contents of the container.

In the area of aerosol can technology the cap for the can, as well as the can itself has undergone several changes in design over the last few decades. Originally, the body of the can (usually an elongate cylinder) was provided with an identical concentric flange top and base, ostensibly to protect the get up applied to the body of the can from impact damage during transit.

The flange top or exterior flange was integral with a dome shaped head of the can. The dome was typically provided with a flange head base or interior flange and a flange head top. Concentrically located within the flange head top was a spray nozzle operatively connected to a valve member that is liable to accidental discharge through a downward pressure applied to the nozzle unless protected by a cap.

The first type of cap used with such a can (known as an "over-cap") was an elongate cylinder closed at one end with a flange base mouth adapted to engage with the exterior flange in a complementary manner. Such complementary engaging, usually in a snap-fit arrangement, was usually provided by a plurality of spaced radial projections located on the interior rim of 25 the mouth. In this way, the cap, once fitted, would prevent depression of a spray nozzle.

Using the same type of can body, another generation of caps were developed that were cylindrical and devoid of a flange base. These so-called "snap-lock" caps were provided with ^ 10 G:\190700NZ Ps.406.doc a plurality of planar, downwardly projecting, resilient, cantilevered teeth located on the internal rim of the mouth of the cap.

These teeth would engage with can through a snap fit by overlying the interior flange in a complementary manner instead of overlying the wider exterior flange, thus dispensing with 5 the need for a cap with a flange base.

With the advent of spin-necking and the realisation that there was no real need to protect the get up on the body of the can through the use of an exterior flange that projected from the body of the can, the exterior flange and as a result the interior flange, became, was allowed to become more narrow than the diameter of the body, thus allowing cylindrical caps without flange bases, but nevertheless with spaced radial projections located on the interior rim of the mouth to be used to snap fit with the narrower diameter exterior flange.

In this way the exterior surface of the cap once fitted to the can, would now be substantially flush with the exterior surface of the body of the can.

The use of increasingly more dangerous substances in cans and the increasing numbers of 15 instances of young children being harmed by such substances on account of the ease of access to the contents of such cans led to the development of so-called "child-proof' caps.

These tended to be of the type where an internal downwardly depending concentric column located on the internal top surface of the cap and provided with a pair of opposing radial projections located on the interior surface of this column was so-sized and shaped as to snap fit over the flange head top to affix the cap to the can.

The exterior sides of the cap transverse to the radial projections are provided with a pair of opposing "U" shaped cut outs so linked to the column as to cause the radial projections to move apart when the cut outs are squeezed, thus allowing the cap to be removed from the can. As young children would not have the strength to perform this action, these types of "child-proof' caps have become wide spread.

With the development of more exotic container contents, the need for tamper-evident caps for aerosols has suddenly become a requirement. The current generation of whipped cream aerosol cans tend to comprise two ingredients, cream and a propellant. The propellant typically used is nitrous oxide (laughing gas).

G:\190700NZ Ps.406.doc It is well known that these can contents separate, if left for long periods (cream below, propellant on top). The problem with such aerosol containers is that young teens, for a laugh (literally) will remove the cap of such a can, shove the nozzle up their nose, (which by coincidence it is well designed for) depress the nozzle "button" and receive an instant 5 "High".

Attempts to solve this problem have revolved around applying a close fitting cylindrical sleeve of clear plastics material that overlies the join where the cap meets the body of the can.

However, this is unsatisfactory as it is expensive as a process to carry out and for the 10 determined "laughing gas inhaler enthusiast", it is possible, although tricky, to replace the cap without disturbing the plastics sleeve and thus give the impression that the aerosol has not been tampered with.

Forms of tamper proof cap do exist and they involve breaking an otherwise integral seal that initially locks the cap to the container, however once the seal has been broken, the cap tends 15 to no longer "snap fit" back to the can in a satisfactory manner.

It is an object of the present invention to attempt to alleviate the problem as specified herein through the re-design of the cap alone, or which will at least provide the public with a useful choice.

STATEMENTS OF THE INVENTION Accordingly in one aspect of the present invention there is provided a tamper proof or tamper evident cap, for use with a container such as an aerosol can, the cap comprising a body having a proximal top portion and a distal base portion, wherein the cap is provided with a plurality of concentric can engagement means, at least one of the engagement means being adapted to be operatively connectable to one portion of the can, whilst at least another 25 of the engagement means is adapted to be operatively connectable to another portion of the can.

Preferably, the distal base portion is provided with the plurality of concentric can engagement means.

G:\190700NZ Ps.406.<toc Although each can engagement means could be so adapted as to engage directly with a can, preferably, at least one can engagement means is adapted to engage directly to the can.

Although each of the can engagement means can be adapted to engage or operatively connect with more than one portion of a can, preferably, each can engagement means is 5 adapted to operatively connect with only one portion of a can.

The portions of a can or can fitment ideally suited to receive an operatively connectable can engagement means are an exterior flange, an interior flange, a flange head top or a dispensing aid such as a spout fitted to a can so whilst the permutations and combinations of can engagement means to can portion, are in reality limited, more preferably, therefore, at least one of the can engagement means is adapted to operatively connect with an exterior flange of a can whilst at least one other can engagement means is adapted to operatively connect with an interior flange of a can.

More preferably still, at least one of the can engagement means is adapted to operatively connect to an exterior flange of a can whilst at least one other can engagement means is 15 adapted to operatively connect to a can fitment.

Preferably, the cap is provided with a frangible portion to enable a portion of the cap provided with one can engagement means to be completely separated from the remainder of the cap.

There may be two or three can engagement means and aspects of one can engagement means may be functionally connected to one or more of the other can engagement means through, for example, opposing surfaces of a wall mutual to both can engagement means. However, this is going to be inevitable if the entire cap is a single piece of plastics material.

Thus for the purposes of clarity, all because separate can engagement means share a mutual aspect, this does not deprive each of the can engagement means of the fact that they are 25 distinct and separate. The issue is more one of what portion of a can or can fitment is each can engagement means intended to engage with.

Preferably therefore, there are only two distinct can engagement means.

G:\I90700NZ Ps.406.doc Preferably, one of the can engagement means is designed to remain attached to the can (usually the neck or body) after the frangible portion has been broken. This will provide evidence of tampering as the public will be able to see clearly whether a 'seal' (the frangible portion) has been broken and thus whether someone has had access to such a can.

It may be possible to redesign a can or container to have a screw thread (like a plastics milk bottle) so that removal of the cap could occur through a rotary action. However, the cost of redesigning a standard can or container would be prohibitive and in any event, can or container redesign is not the remit of this invention, cap redesign is.

Nevertheless, even if it were possible to redesign the cap in some way to provide a sloping 10 internal thread that could 'bite' against the flange of a container to assist frangible portion breakage during a rotary action of the cap, even more preferably, the frangible portion is broken by a movement of the cap in a direction that is substantially along a direction of a longitudinal or principal axis of the cap.

If the cap is circular, then more preferably, this movement is a linear or rotary action 15 substantially orthogonal or oblique to the radial lines of the circular cap.

The frangible portion preferably comprises a plurality of sections, more preferably, at least three sections and yet more preferably still, a plurality of sections in the range of 2-16.

Instead of a smooth finish to the exterior surface of the cap, a knurled portion to assist grip and subsequent frangible portion breakage could be provided as in reality, the frangible 20 portion is going to be broken by bending the cap in a direction substantially orthogonal to the radial axis of a can that it has been attached to. Therefore it would be advantageous to be able to grip the cap in a satisfactory manner to facilitate initial breakage of the frangible portion.

The cap could be any colour or shape, however, a distinctive shape at least would establish in 25 the minds of the buying public the fact that this is a new type of cap/container combination.

Yet more preferably still, the frangible portion is bevelled towards a virtual point below the cap along its longitudinal or principal axis.

G:\190700NZ Ps.406.doc Although it is conceivable that each can engagement means could be identical. Preferably, each of the can engagement means is not identical. In this way, if a frangible portion is broken, one part of the cap could be so designed as to remain affixed to a can that it has been fitted to whilst the other could break away providing a means of tamper-evidence for a can 5 fitted with such a cap.

A preferred can engagement means is through the use of a plurality of spaced apart teeth adapted to grip a particular aspect of a can. These teeth can vary in number from three to twenty and can be any appropriate shape.

In fact the design of the teeth can be selected without further inventive thought by the skilled 10 addressee of this specification. As such, they need not be described any further here.

Alternatively, a continuous inwardly projecting radial rib could be provided to enable some form of snap fit to a complementary designed can fitment (such as a dispensing aid or spout snap fitted to a can) to take place, if this form of can engagement means fits directly to such a can fitment.

The invention includes within its scope, a tamper proof or tamper evident cap substantially as herein described with reference to and/or as illustrated in any one of the accompanying drawings.

The invention further includes within its scope a container incorporating a tamoper proof or tamper evident cap as specified herein.

The invention fiirther includes within its scope a container in the form of an aerosol can incorporating a tamper proof or tamper evident cap as specified herein.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention will now be more particularly described by way of example only with reference to the accompanying sheets of drawings in which: Figure 1 illustrates a front view of a cap showing a minor base portion of the cap connected to a major top portion of the cap via a frangible area.

G:\190700NZ Ps.406.doc Figure 2 illustrates a front view of the cap shown in figure 1 once the frangible area has been broken and the cap has been separated into its major and minor fragments.

Figure 3 illustrates a sectional view of the cap shown in figure 1 showing both minor and major portions of the cap still connected and also showing the internal arrangement of the 5 major portion of the cap.

Figure 4 illustrates a sectional view of the cap shown in figure 2.

Figure 5 illustrates an isometric view of a base end of the cap shown in figures 2 & 4.

Figure 6 illustrates a sectional view of a container in the form of an aerosol can, fitted with a cap as shown in figure 1.

Figure 7 illustrates a sectional view of an alternative embodiment of the present invention where one of the can engagement means is not directly fitted to the can but fitted to a spout that is fitted to the can.

Figure 8 illustrates a sectional view of the cap shown in figure 7 once the frangible area has been broken and the cap has been separated into its major and minor fragments.

Figure 9 illustrates an isometric view of the cap shown in figures 7 & 8 once the frangible area has been broken and the cap has been separated into its major and minor fragments.

Figure 10 illustrates an alternative the cap shown in figures 7 & 8 once the frangible area has been broken and the cap has been separated into its major and minor fragments.

DESCRIPTION OF THE PREFERRED EMBODIMENT Figure 1 shows a front view of an integral white plastics cap of the present invention formed from the man-made polymer, polypropylene and is generally referenced (1). The cap (1) comprises two portions, a major top portion (2,3) and a minor base portion (4,5,6,7,8,9), both joined together via a frangible area (5) to form the cap (1).

The major top portion (2,3) comprises an elongate, circular dome, (2,3) having a truncated 25 concentric circular top (3) with a single substantially convex parabolic sloping exterior wall (2) that is integral to and depending from the entire circumferential periphery of the top (3), G:\190700NZ Ps.406.doc to form a closed end for the cap (1) at the top of the portion (2,3) and a concentric circular open end or mouth that is parallel with the top (3) at the base of the portion (2,3).

The sloping wall (2) is provided with a point of inflection towards the base of the portion (2,3) denoted by the dotted line "A" that is parallel with the top (3).

For the puiposes of this specification and any issues regarding clarity, this point of inflection "A" separates the cap (1) into two distinct portions, a proximal top portion and a distal base portion.

A further point of inflection at the very base of the portion (2,3) is denoted by the dotted line "B" which is also parallel with the truncated top (3).

The minor base portion (4,5,6,7,8,9) comprises a flat circular ring for a base that is concentric with, greater in diameter to and parallel with the top (3) and is provided with a wall (4) whose exterior surface is uniform and cylindrical, that rises from the base and terminates with the start (8) of a truncated dome (5,6,7,8,).

The top of the dome (5,6,7,8,) is castellated to form a series of six substantially equally 15 spaced apart, substantially rectangular peaks (6) and six corresponding troughs (7), the longer sides of each peak (6) and trough (7) being parallel with the top (3) and the dimensions of each peak (6) and trough (7) being substantially equal.

The frangible area (5) coincident with point of inflection "B" connects the major top portion (2,3) with the minor base portion (4,5,6,7,8,9) via a wasted section located at "B" that 20 overlies the upper most longest side of each peak (6).

Turning to figure 2, this shows the cap (1) separated along the frangible area (5) into its two component portions, the major top portion (2,3) and the minor base portion (4,5,6,7,8,9). Although present and partially shown in figure 1, a uniform internal wall (12) is revealed in figure 2.

This internal wall (12) is cylindrical, commences at the point of inflection "A" and depends vertically downwards from the major portion (2,3) and terminates at a point some where between inflection point "B" and the base of the wall (4).

G:\190700NZ Ps.406.doc Revealed for the first time, is the bevelled cut (13) of the frangible area (5) located on the major portion (2,3). This cut (13) slopes towards the internal wall (12).

Figure 3 shows a section of figure 1 which reveals the entire internal arrangement of the cap (1) from the top (3) to the base of the wall (4).

The major top portion (2,3) of figure 3 shows an annular arrangement of fourteen downwardly depending, resilient, radially spaced apart, concentric, identical rectangular teeth (10) that are cantilevered out from the start of the interior surface of the internal wall (12), the cantilever angle being denoted by the Greek letter 0 which is 35°.

The minor base portion (4,5,6,7,8,9) of figure 3 is provided with an annular continuous projection (9) of uniform cross-section along the internal wall of, and parallel with the base of the wall (4), the mid point of the projection (9) being substantially coincident with the base end of the wall (12).

Figure 4 shows the cap as shown in figure 3 after it has been broken along the frangible area (5) to reveal the fully and bevelled surface (11). The wasted sections of the surface (11) that 15 are coincident with the ridge tops of the peaks (6) of the truncated dome (8) of the minor base portion (4,5,6,7,8,9) are only located where they oOverlie the ridge tops.

Figure 5 shows an isometric view of the cap after it has been broken along the frangible area (5).

Figure 6 shows a section of a typical modern aerosol can (28) formed using the technique of so-called "spin-necking" that is fitted with the integral cap (1) prior to a breakage of the frangible portion (5).

The can (28), typical of those in the market place, has an exterior flange (26) (or can flange neck) and an interior flange (27) (or can flange shoulder).

In use, direct fitment of the cap (1) to the can (28) occurs when the projection (9) and 25 exterior surface of the internal wall (12) initially resiliently passes over the surface that makes up one portion of the can (1), the can flange neck (26). This links the can top (25) to the can body. Fitment may be carried out by first warming the cap (1) to enable it to expand slightly and to make it more flexible.

G:\190700NZ Ps.406.doc The projection (9) and internal wall (12), then resiliently flex back to their equilibrium position around the base of the flange neck (26) such that the much of the flange neck (26) overlies the projection (9) and the internal wall (12) lies flush with and contacts the rear of the flange neck (26) thus "snap locking" the cap (1) to the can (28).

Cooling of the cap (1) further locks it into place.

The flange neck (26) is to all intents and purposes captured and surrounded by a surface of the walls (4 & 12) and the projection (9). In this way, these features (4,9,12) together serve as one type of can engagement means that operatively connect the cap (1) to the can (28) by direct engagement.

At the same time, each of the resilient teeth (10) initially radially flex outwards to narrow the angle 0 of each tooth (10), as they pass over another portion of the can, the can flange shoulder (27) {located towards the base of the can top (25)}, before each of the teeth (10) subsequently return substantially to their equilibrium position gripping the underside of the flange shoulder (27).

In this way, the teeth (10) and the interior surface of the wall (12) to which they are integral with, act as a second, separate and distinct type of can engagement means that operatively connect the cap (1) to the can (28) by direct engagement. As we are dealing with a plastics to metal fitment in this particular instance that needs to be demountable, teeth are used as opposed to a rib.

In this way, the cap (1) is "snap locked" to the can (28) in two positions using two can engagement techniques, one that is relatively difficult to remove (4,9,12) and one that is relatively easy to remove (10,12).

This is because the teeth (10) are separated by a number of substantially equally spaced gaps which allow a greater degree of independent movement of each tooth (10) as opposed to the walls (4,12) and projection (9) which are all single continuous bands which limit any independent movement of any aspect of these features relative to another aspect of these same features.

To remove the cap (1), the major top portion (2,3) is lifted or bent/rotated relative to the longitudinal or principal axis of the can (28) and as it is so moved, the minor base portion G:\190700NZ Ps.406.doc (4,5,6,7,8,9) remains trapped or locked around the exterior flange (26) of the can (28) allowing the frangible area (5) to subsequently break, thus allowing the major top portion (2,3) of the cap (1) to be removed from the can (28).

As this breakaway occurs, the teeth (10) as a result of their more flexible degrees of 5 movement, are (as opposed to being trapped like the other can engagement means (4,9,12)) able to resiliency flex outwards once again allowing the major top portion of the cap (1) to be removed from the can (28).

Because of the design of the flexible teeth (10), the major top portion (2,3) of the cap (1) can still mate with the flange shoulder (27) to "reseal" the now no longer integral cap (1) to the 10 can (28) as the teeth (10) are still able to flex around and subsequently "snap-lock" around the interior metal flange (27) of the can (28).

This arrangement of a frangible area (5) is a new form or "tamper-evident" means that will deter someone from ripping the cap (1) off of an aerosol can (28), as it will be visibly clear to a third party that such an act has occurred.

Figure 7 shows a sectional view of an alternative embodiment of the cap (1). To all intents and purposes, the minor base portion (4,5,6,7,8,9) is identical to the previous embodiment and so is its means of fitment to the can (28) and thus will not be described further.

However, the other can engagement means (33,34) comprises a concentric circular columnar+ wall (33) that downwardly depends from the internal side wall of the major top 20 portion (2,3). The internal face of the wall (33) terminates with a continuous inwardly radially projecting rib (34) of similar dimensions throughout its circumference.

This rib (34) is designed to snap fit over a complementary sloping wall 32. The wall (32) forms part of a plastics spout 30 that is "snap lock" fitted to the flange head top (29) of the can (28) via a rib (31) in a similar manner to how the rib (9) "snap locks" the cap (1) to the 25 can (28).

Thus, in use, in this arrangement at least one of the can engagement means (33,34) does not fit directly to the can (28), but instead, fits to the can fitment fitted to the can (28).

G:\190700NZ Ps.406.doc As, in this particular instance, we are dealing with a plastics to plastics engagement, a continuous rib (34) instead of separate teeth as described in the previous embodiment can be used. However, this does not negate the possibility that teeth could not be used instead.

In embodiments not illustrated, it may yet be possible to so design the cap (1) so that the 5 more flexible of the two can engagement means could be designed to engage directly with the flange head top (29) of the can (28).

Alternatively, the other or indeed even a third can engagement means downwardly depending from either the interior surface of the top (3) or radially extending from the internal wall (2) that is also flexible, could be used to operatively connect to the flange head top (29) or the spout (30).

This invention may also be broadly be said 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 parts, elements or features, and where specific integers are mentioned herein which have known equivalents, such equivalents are deemed to be incorporated herein as if individually set forth.

G:\190700NZPs.406-doc 14

Claims (11)

1. A tamper evident aerosol can cap, comprising: a body having a proximal top portion provided with a can engagement means adapted to engage directly or indirectly with one portion of the can and a distal base portion provided with a can engagement means adapted to engage with another portion of the can, the arrangement of the can engagement means being such that they are both concentric, the cap also being provided with a frangible portion to enable the proximal top portion of the cap to be completely separated from the distal base portion, wherein once the cap has been fitted to the can with both can engagement means engaging the can, the distal base through its can engagement means is adapted to remain attached to the can after the frangible portion has been broken, whereas the proximal top portion of the cap once separated from the can may be re-fitted to the can using the proximal top portion can engagement means.

2. A cap as claimed in claim 1, wherein at least one can engagement means is adapted to engage directly to the can.

3. A cap as claimed in claim 1, wherein at least one of the can engagement means is adapted to operatively connect to an exterior flange of a can whilst at least one other can engagement means is adapted to operatively connect to an interior flange of a can.

4. A cap as claimed in claim 1, wherein at least one of the can engagement means is adapted to operatively connect to an exterior flange of a can whilst at least one other can engagement means is adapted to operatively connect to a can fitment. 15

5. A cap as claimed in any preceding claim, wherein each of the can engagement means is not identical.

6. A cap as claimed in any preceding claim, wherein the frangible portion comprises a plurality of sections.

7. A cap as claimed in any preceding claim, wherein the frangible portion is bevelled towards a virtual point below the cap along its primary or longitudinal axis.

8. A cap as claimed in any preceding claim, wherein one of the can engagement means is through the use of a plurality of resilient spaced apart teeth adapted to grip a particular aspect of a can whilst another of the can engagement means is a continuous circumferential rib.

9. An aerosol container incorporating a tamper evident cap as claimed in any preceding claim.

10. A tamper evident cap substantially as herein described with reference to and as illustrated in figures 1-6 of the accompanying drawings.

11. A tamper evident cap substantially as herein described with reference to and as illustrated in figures 7-10 of the accompanying drawings.