Field of the Invention

This invention relates to an enclosed capsule for containment of product and a method of forming same.

Background to the Invention

There are many situations in which a product needs to be encapsulated. For example it is common to encapsulate a medical treatment product such as a tablet. The encapsulation is intended for packaging and storage of a plurality of tablets prior to use but in such a manner as to provide for easy dispensing of the tablets. Another example is the packaging of a drink additive or ingredients in a capsule which is located within a cap for a container. The capsule is one where it can be ruptured so as to release the additive or ingredients into a liquid in the container on which the cap is located. Examples of container caps with a capsule for an additive (whether they be in powder, liquid or tablet form) can be found in my New Zealand patent nos. 500063, 511955 and 512904 the content of which is included herein.

Essentially the capsule is a pocket or cavity of dished form covered by a lid or cover. With capsules for drink additives each capsule will be an individual unit. However, with tablets for medical purposes, for example, a number of pockets will be provided in a single "package" or "tray" and these will be covered by a single cover layer. The user will then puncture the lid over a pocket to recover the tablet residing therein.

The pockets can, according to one known production method, .be formed by a method commonly referred to as cold forming. Other production methods can be used and the inventive concept described herein is not limited solely to cold forming of the dish part of the capsule. Nevertheless, by way of describing the present invention reference will be made to the cold forming production method.

Cold forming Is achieved by placing and holding a cold form foil material. Generally the foil material will be an aluminium foil which is coated with a plastic material(s) such as PVC. The coating(s) help the stretching of the foil.

While the foil is held in place a punching tool comes into contact with it and cold forms a pocket or cavity (dish shape generally) of a size and shape for the product or ingredient intended to be placed therein. The product or ingredient can be placed into the pocket(s) immediately or subsequently to the cold forming process being completed.

Once the product/ingredient has been placed into the pockets, a lidding material is laid out over the punched foil and a sealing iron is then bought down and seals the lidding material to the punched foil by activating glues which have been applied to each.

The sealing tool is made to match up with the corresponding pocket(s)/cavities. The lidding material will also generally be a foil (e.g. aluminium) to which one or more coatings (e.g. plastic) has/have been applied.

The product/ingredient placed in the pocket can be in tablet, granulated or powdered form, for example. These need to be sealed into the resultant capsule as it is only the material of the cold form part and lid which provides a total barrier. Irrespective of how good the foil is, it is thus necessary to have a good seal between the two layers of foil (pocket and lid). Generally this will require an ample sealing area to ensure moisture cannot penetrate into the internal cavity in which the product/ingredient resides.

Naturally in the manufacturing process variations will and do occur in both the punching (cold forming) of the pocket/dish/cavity shape, as well as in the second manufacturing stage of sealing on the lid material. Typically a crisscross type pattern is applied to the foil which provides an ample seal when trays of pockets are used in a normal air environment. However, when the trays or individual capsules cut from the tray are used in a fluid environment, the resultant crisscross patterns can actually provide a channel or channels for fluid leading into the internal cavity by capillary action.

To combat this, larger sealing margins are required. This may be possible with trays. However, with single capsules, and particularly those intended for fitment into container caps, this may not be possible or practical. For example, an increase in sealing area may result in an increased overall size (e.g. diameter) of the capsule which would in turn require an increase in size of the cap which generally is undesirable.

Even with allowance for larger sealing margins with capsules for container caps, consistent and effective sealing cannot be assured. The main cause for this seems to arise from the need to cut the capsule from the tray.

Regardless of whether or not the cutting is accurate, there is generally not enough sealing area to ensure stability of the seal between the cold formed pocket and the lid.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert and the applicant reserves the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in Australia, New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning, ie that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term "comprised" or "comprising" is used in relation to one or more steps in a method or process.

An object of the present invention Is thus to provide an Improved sealed engagement of a lid section to a body section of a capsule intended for sealed containment of a product or ingredients.

A further object of the present Invention is to provide a method of sealing a lid to a body section of a capsule for encapsulating a product or ingredients.

Summary of the Invention

Broadly according to one aspect of the invention there is provided a capsule comprising a body section which incorporates an open topped cavity with a surrounding flange and a lid section engaged over the body section to seal closed the capsule, the area of the lid which is in contact with the flange being adhered to the flange to seal closed the pocket wherein one or more non-intersecting indentations are formed in the lid and underlying flange to enhance the sealing of the capsule.

In a preferred form, there is a plurality of spaced apart indentions. These indentations are preferably substantially concentric to one another and the open top of the cavity. The indentations are preferably of a curved cross- sectional shape.

Broadly in a second aspect of the invention there is provided a method of forming a capsule from metal sheet material comprising the steps of forming an open topped cavity in a first sheet, laying a second sheet over the first sheet, applying a sealing tool to the second sheet to activate adhesive applied to contacting surfaces of the first and second sheets wherein during the application of the sealing tool one or more non-Intersecting indentations are applied to the first and second sheets, at least in the area of contact between the first and second sheets adjacent the cavity.

In the preferred form of the method, there is a plurality of spaced apart indentations. These indentations are preferably substantially concentric to one another and to the cavity about which the indentations are formed.

In one form of the invention a plurality of cavities are formed in a single operation.

According to one form of the invention individual capsules are removed from the construction by a cutting operation. Further aspects of the invention will become apparent from the following description which is given by way of example only.

Description of the Drawings

In the following more detailed description of the preferred embodiment, reference will be made to the accompanying drawings in which:-

Figure 1 is a top plan view of a single unit or "tray" of a plurality of capsules formed according to a prior art construction method, Figure 2 is cross-sectional perspective view of a single capsule cut from the single unit or tray of Figure 1 ,

Figure 3 is a top plan view of a tray formed according to the present invention, and

Figure 4 is a cross-sectional perspective view of a single capsule cut from the tray shown in Figure 3.

Description of the Preferred Embodiment

The tray 10 and capsule 11 cut therefrom, as shown in Figures 1 and 2 respectively, are formed according to known art. The tray 10 comprises a first sheet of foil formed into a plurality of cavities as previously described e.g. by cold forming. Over this a second sheet 12 of foil is placed. A sealing tool is applied to the surface of the first sheet to activate glues on the opposed surfaces of the first and second sheets. This causes the contacting surfaces of the sheets to adhere to one another.

The sealing tool is of a construction such that it applies into both the first and second sheets a crisscross pattern 13 of grooves, channels or the like ("indentations"). As shown, the first sheet, where it extends over the open top of each cavity, remains unaltered. A capsule 11 cut from tray 10 is shown in Figure 2. The capsule 1 1 thus has a body 14 in which a pocket or cavity 16 is formed by the e.g. cold forming of the foil sheet to create a cavity 16 into which a tablet or granulated or powder product/ingredients can be placed. A flange 17 surrounds the open top of the cavity 16. The lid 18 formed from the second sheet 12 extends over the open top of cavity 16 and the flange 17. The opposed contacting surfaces of lid 18 and flange 17 are glued together.

As shown, the crisscross pattern 13 created by the sealing tool is formed in both the lid 18 and flange 17. The pattern 13 is a series of intersecting, preferably straight, indentations 19.

According to the present invention, as shown in Figures 3 and 4, the sealing tool applies at least one and preferably a plurality of non- intersecting indentations 20 in the lid 18 and flange 17. These indentations in plan are of a form which corresponds to the cross-sectional shape of the open top of the cavity 16. Generally, the cavity 16 will be of circular cross-sectional shape hence the indentations 20 will be, as shown, spaced apart rings or bands.

By employing non-intersecting indentations 20 the problems associated with the crisscross pattern 13 are overcome because there Is no continuous channel or passageway from the peripheral edge of the capsule 11 to the cavity 16. Even if the cutting of a capsule from tray 10a (of Figure 3) is semi-accurate, the resultant individual capsule (Figure 4) is well sealed and thus suitable for use in fluid environments. This is achieved while keeping the sealing area to a minimum. Hence, the overall size of a container cap to accommodate the capsule 1 1 can also be kept to a minimum. The invention is open to modification as will be appreciated by those skilled in the art. For example, the cross-sectional shape of the indentation 20 can vary. Also, the number of spaced apart indentations 20 can vary, and while one indentation is a possibility, it is believed a plurality of indentations is preferable.

Where in the foregoing description particular integers are described it is envisaged that their mechanical equivalents can be substituted as if they were set forth herein.

Particular examples of the invention have been described and it is envisaged that improvements and modifications can take place without departing from the scope of the attached claims.