GB2344101A

GB2344101A - Time indicator for packaging closures

Info

Publication number: GB2344101A
Application number: GB9825767A
Authority: GB
Inventors: Brent Lee Taylor; Diane Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-11-26
Filing date: 1998-11-26
Publication date: 2000-05-31
Anticipated expiration: 2018-11-26
Also published as: GB2344101B; GB9825767D0

Abstract

A closure for a container comprises timing means and means for generating an audible or visible warning signal when the timing means indicates that a predetermined time interval has elapsed from the occurrence of a trigger event. The trigger event may be the first sealing of the container by a manufacturer to signal a "best before" date or the first opening of the container by a user to signal a "use after opening" date. In one embodiment, a first compartment 26 of the closure contains a first material 30 and a second compartment 28 contains a second material 32 with a seal 24 between the first and second compartments 26,28, which is broken when the trigger event occurs. The warning signal is a visible signal generated as a result of contact between the first and second materials. Alternatively, the timing and signalling means may be electronic.

Description

TITLE Time indicator for packaging closures DESCRIPTION Technical field The invention relates to the field of packaging for consumer goods and particularly for perishable goods that must be used within a predetermined period after manufacture or first opening.

Background of the invention Perishable goods such as food and medicines frequently have printed on their packaging a"best before"date or a "use by"date, which is a date calculated at a predetermined interval from the date of manufacture. The consumer is thereby warned not to use the goods after that date in case they should have begun to deteriorate in quality or may even have become dangerous. A similar concept is the"sell by"date, which warns retailers not to keep the goods for too long after the date of manufacture before selling them.

Perishable goods that are packaged in sealed containers may additionally or alternatively carry a"use after opening"date. This warns the consumer only to use the goods within a stated period after the consumer has opened the packaging and thereby exposed the goods to environmental conditions instead of the conditions sealed into the container by the manufacturer. The manufacturer naturally does not know when the packaging will be opened by the consumer so the manufacturer can only advise what is a suitable"use after opening'period. It is up to the consumer to remember when the package was opened and to calculate the resulting"use by"date correctly. With increasing demand for consumer safety, there is a need for a more reliable system of determining"use by"dates.

Other current issues in the area of consumer safety concern the correct handling and storage of food by the manufacturer and the consumer to ensure that it is safe to eat; and in cases where food is found to be unsafe, the allocation of blame between the consumer and the manufacturer. It would thus be desirable to have means for recording the storage conditions of the food at various times.

There have also been incidents of blackmailers and ill-wishers tampering with food on supermarket shelves.

Accordingly, there is a demand for closures that reveal evidence of having been opened or otherwise tampered with.

When medicines are sold, they are generally prescribed to be taken according to a strict regime or at least are not to be taken too frequently in order to avoid undesirable side effects. Again, this places a burden on the consumer to remember to take the medicine at appropriate times and only at appropriate times. A more foolproof system would be welcome.

The invention The invention provides a closure for a container, comprising timing means and means for generating an audible or visible warning signal when the timing means indicates that a predetermined time interval has elapsed from the occurrence of a trigger event.

By building a timing means into the closure, the invention can provide a flexible solution to many of the problems previously explained. By a suitable choice of the trigger event and the predetermined time interval, a consumer of goods that are contained in packaging incorporating the invention can be spared the burden of correctly calculating and remembering the"use by"date.

In one embodiment of the invention, the trigger event is the first occasion when the closure of the container is closed. This will generally occur during packaging of the goods by the manufacturer. Thus the predetermined interval can be set to coincide with the"sell by"date, the"best before"date or the"use by"date of the goods.

The warning signal can give the retailer or consumer a clear sign that the container in question should no longer be sold or used, without any need to consider the date as such.

In an alternative embodiment of the invention, the trigger event is the first occasion when the closure of the container is opened, having previously been closed. This will generally occur when the goods are first used by the consumer. Thus the predetermined interval can be set to coincide with the"use after opening"date of the goods.

The warning signal can give the consumer a clear sign that goods from the container in question should no longer be used, without any need to remember the date on which the container was opened.

With suitable resettable timing means, the predetermined interval can be triggered on each occasion when the container is opened. This allows the generation of a signal at repeated intervals, which has applications such as reminding a patient to take a dose of medicine or reminding the user to replace the cartridge in a water filter.

In a preferred embodiment of the invention, the closure comprises a first compartment containing a first material, a second compartment containing a second material and a seal between the first and second compartments; wherein when the trigger event occurs the seal is broken, and the warning signal is a visible signal generated as a result of contact between the first and second materials.

The first material may be fluid and the second material may be embedded in a plastics material so as to achieve a predetermined delay between the time when the first material is admitted into the second compartment and the time when the first and second materials come into sufficient contact to result in generation of the visible signal. The predetermined delay may be up to three months using currently available such materials. Alternative methods of creating a predetermined time delay would involve slowing the transport of the fluid first material into the second compartment, e. g. by diffusion or capillary action.

It is preferred that the first material should be water and the second material should be a moisture-sensitive colour change material. Other combinations of materials are possible, such as an acid (e. g. citric acid) as the first material and an acidity-sensitive colour change material as the second material. The first material need not be liquid but may be a gas to which the second material is sensitive, e. g. oxygen.

For most applications, a sudden colour change is desirable in order to give a definite indication whether the goods are safe or not. However, it is also possible to arrange for a more gradual colour change as a reaction between the materials proceeds. This gives the user some advance warning that the goods are nearing the end of their life.

This embodiment of the invention involves no moving parts and requires no source of power, apart from that applied by the person who opens or closes the packaging. A colour change provides a clear and unambiguous signal and, because the signal is triggered by the breaking of a seal, it should be irreversible. Accordingly, this embodiment lends itself to cheap and simple mass production for incorporation into high volume consumer items.

In an alternative embodiment of the invention, the timing means is an electronic clock. In this embodiment, the warning signal may be a visible signal generated by an electronic display device, such as one or more LEDs, or an audible signal generated by an electronic sound generator.

Although an electronic embodiment of the invention is likely to be more complex and more expensive to manufacture than a chemical or mechanical embodiment, it does have advantages that make it suitable for certain applications. An electronic timer is likely to be more precise and also programmable with a wider range of intervals than chemical or mechanical timing means. An electronic timer can be reset so that, for example, each time the container is opened the start of a new predetermined time interval is triggered. This may be useful in a container for medicines, to remind the patient each time another dose is due. An electronic timer can also be programmed with more than one interval, for example to generate warning signals of the"sell by"date and the"use by"date successively.

An electronic embodiment of the invention also provides the flexibility to combine it with other electronic devices. For example, once a container carries a built-in timer, it becomes possible to record a history of the storage conditions of the container. Thus a temperature sensor could be provided to generate a warning signal if a frozen food container is allowed to defrost and to record the time when that happened. A shock sensor could be provided in the case of fragile goods. The history could be checked at the time of sale of the goods by the retailer and the time of sale could even be recorded in the device so that in the event of any dispute by the customer it could be determined whether damage to the goods occurred before or after their sale.

It will be understood that the various embodiments described are not necessarily mutually exclusive, so that electronic, chemical or mechanical timing means may be used in combination. Similarly both audible and visible warning signals may be generated together if appropriate.

The drawings Fig. 1 is an exploded perspective view showing how a screw cap in accordance with the present invention may be assembled.

Fig. 2 is a plan view of the indicator disc of Fig. 1.

Description of a preferred embodiment Figure 1 shows how a screw cap for a container in accordance with the invention may be assembled from three parts: a cap 2, an indicator disc 4 and a retainer 6. The cap 2 comprises a generally cylindrical wall 8 closed at one end by an end face 10. The outer surface of the cylindrical wall 8 has longitudinal ribs 12 or other means to aid the grip of a user when turning the screw cap to open or close the container. If, as is generally the case, the end face 10 of the cap is formed of an opaque material, a window 14 is provided in the end face 10. The window 14 is filled with a transparent material and sealed.

The indicator disc 4, described in more detail below, is placed inside the cap 2 against the end face 10 of the cap. The indicator disc 4 is held in place inside the cap 2 by the retainer 6. The retainer 6 comprises a generally cylindrical wall 16 closed at one end by an end face 18.

The outer diameter of the retainer 6 is smaller than the inner diameter of the cap 2 so that the retainer 6 can be fitted inside the cap 2, trapping the indicator disc 4 between the end face 18 of the retainer 6 and the end face 10 of the cap 2. The inner surface of the cylindrical wall 16 of the retainer carries a screw thread (not shown) for engagement with a corresponding exterior screw thread of a container to which the screw cap is to be attached.

An annular flange 20 may extend a short distance radially outwards from the outer surface of the cylindrical wall 16 of the retainer 6. This may engage behind a corresponding annular flange (not shown) or within a corresponding annular recess (not shown) on the inner surface of the cylindrical wall 8 of the cap 2, to secure the retainer 6 in position in the cap 2.

Figure 2 illustrates the indicator disc 4 in more detail.

The disc comprises two foil sheets sealed together along a circular line 22 around the rim of the disc 4. The two sheets are also sealed together along a diameter 24 of the disc 4 to create first and second sealed compartments 26,28 in the disc 4. In the first compartment 26 is placed a known quantity of humid air 30. In the second compartment 28 is placed a moisture-sensitive colour change material 32 that changes colour in the presence of water. The colour change material 32 is embedded in a plastics substrate that delays the onset of the colour change for a predetermined time interval after moisture is introduced to the second compartment 28. One such plastics material with colour change material embedded therein can be obtained from Capitol Specialty Plastics Inc of Fultonville, New York, U. S. A.

The indicator disc 4 is placed in the cap 2 in such an orientation that the colour change material 32 in the second compartment is visible through the window 14 in the cap 2. A suitable position of the window 14 relative to the second compartment 28 is shown in dashed lines in Fig. 2. The colour change material 32 may be present a uniform area of colour to view through the window 14.

Alternatively, the colour change material 32 may be patterned or masked such that a warning message becomes visible through the window 14 when the colour change occurs.

The operation of the screw cap according to the invention will now be explained. A container is filled with goods by the manufacturer under sterile, dry or other suitable conditions. A screw cap assembled in accordance with Fig. 1 is screwed onto the container to seal it. The first and second compartments 26,28 of the indicator disc 4 remain separated from one another by the diametric seal 24.

When subsequently the screw cap is unscrewed from the container, which will generally be when the container is first opened by the consumer, the diametric seal 24 of the indicator disc 4 is broken and humid air 30 from the first compartment 26 is allowed to enter the second compartment 28. This is the trigger event for the generation of the warning signal. The embedding of the colour change material 32 in plastics material determines a delay before the reaction that produces the colour change occurs. This delay is predetermined to match the"use after opening" time preferred by the manufacturer. When the predetermined interval has elapsed, the colour change takes place and the altered colour can be seen by the consumer through the window 14 of the cap 2. The consumer is thereby alerted that the goods from the container should no longer be used.

It is envisaged that the breaking of the diametric seal 24 to trigger the warning signal will be brought about by relative rotation between the cap 2 and the retainer 6 as the screw cap is opened. If the indicator disc 4 is attached to both the cap 2 and the retainer 6, then relative rotation between them will create shear forces that may be sufficient to rupture the seal 24 at a specially weakened point. Alternative mechanical means for directly puncturing the seal 24 can be envisaged.

A ratchet or other means can be provided to ensure that, in the embodiment described above, relative rotation between the cap 2 and the retainer 6 only occurs when the screw cap is opened. By using a similar ratchet in reverse, it can be arranged that the seal 24 is ruptured when the screw cap is first closed, namely when the goods are packed by the manufacturer. That provides an alternative warning signal based on a"best before"date calculated from the time of manufacture.

One embodiment of the invention (not illustrated) using electronic indicator means has the same general construction as the screw cap described above, comprising an indicator disc sandwiched between a cap and a relatively rotatable retainer. The indicator disc carries a battery, a timing circuit and a light-emitting diode (LED). A pair of contacts is provided between one terminal of the battery and the timer, such that when a conductor mounted on either the cap or the retainer is placed across the contacts, a circuit between the battery and the timer is completed. The cap and retainer are arranged so that relative rotation between them occurs either on first closing or on first opening the screw cap, as previously described. When relative rotation occurs, the conductor completes the circuit between the contacts and triggers operation of the timer. After a predetermined time, the timer causes the LED to be illuminated, which is visible through a window in the cap to act as the warning signal.

Claims

CLAIMS 1. A closure for a container, comprising: timing means; and means for generating an audible or visible warning signal when the timing means indicates that a predetermined time interval has elapsed from the occurrence of a trigger event.
2. A closure according to claim 1, wherein the trigger event is the first occasion when the closure of the container is closed.
3. A closure according to claim 1, wherein the trigger event is the first occasion when the closure of the container is opened, having previously been closed.
4. A closure according to any of claims 1 to 3, further comprising : a first compartment containing a first material, a second compartment containing a second material and a seal between the first and second compartments; wherein the seal is broken when the trigger event occurs and the warning signal is a visible signal generated as a result of contact between the first and second materials.
5. A closure according to claim 4, wherein the first material is a fluid and the second material is embedded in a plastics material so as to achieve a predetermined delay between the time when the first material is admitted into the second compartment and the time when the first and second materials come into sufficient cortact to result in generation of the visible signal.
6. A closure according to claim 4 or claim 5, wherein the first material is water and the second material is a moisture-sensitive colour change material.
7. A closure according to any of claims 4 to 6 which is a screw cap for a container, wherein the first and second compartments are located inside the screw cap and a window is formed in the screw cap, through which the visible signal can be seen from outside the screw cap.
8. A closure according to any of claims 1 to 3, wherein the timing means is an electronic clock.
9. A closure according to claim 8, wherein the warning signal is a visible signal generated by an electronic display device.
10. A closure according to claim 8, wherein the warning signal is an audible signal generated by an electronic sound generator.
11. A closure substantially as described herein with reference to the drawings.