Background Art It has been well known for a long time that one of the major problems connected with the use of cans as containers of beverages or other liquids for human consumption (but also including ordinary cylindrical tin cans designed to contain solid food products) is that of protecting the top portion of the can (or rather, the portion of it that is designed to be opened to allow the contents to be poured out) against contamination by contact with impurities during storage, transportation and sale. Contamination is an especially serious problem in the case of beverage cans with the familiar snap opening top from which the consumer can pour the beverage or drink it directly from the can.

Numerous types of covering elements have been devised to overcome this problem. These come in various forms designed to fit, in such a way as to be easily removed, at least over the portion of the can top where the can opening means are located. In some cases, the top of the can is covered completely.

These covering elements, some of which are disclosed in patents US-5.105.964, US-5.221.020 and US-5.647.497, provide a good seal over the can tops since their shape exactly matches the shape of the can. They are, however, uneconomical not only because of the complexity of the moulds used to make them but also because it is necessary to set up extremely complex purpose-designed additional stations on the can packaging lines. In many cases, the high costs involved and the nature of the end product are such that the investment in an accessory of this type cannot be justified.

Also known is another type of covering element that can be obtained by moulding the cover directly on the top of the can as the

can moves along the production line.

Patents US-4.281.502 and US-5,088,269 envision a process for making container covers which uses, along the product feed line, a forming plate placed over the cans and having a circular opening in it, a sheet of thermosensitive plastic placed between the plate and the cans moving forward, and means for heating the plastic sheet. In practice, the heating means act on the portion of the sheet concerned through the circular opening in the forming plate in such a way as to soften the sheet. The forming plate then moves down over the can and causes the softened plastic sheet to adhere to the top of the can.

This process cycle, although it is more flexible in applying the covers to the cans, involves heating and cooling the portion of film concerned. This greatly increases the costs of the process not only because of the equipment required but also because the movements of the various component parts of the station must be constant and precisely coordinated and are therefore slow.

Further, for the method to be economical, without significantly raising the unit cost of the cans, it must be used on packs of products which reach the point of sale in considerable numbers since the forming plates must have the openings made in them in defined sizes and styles and the thermosensitive plastic sheet must be cut to the size required by the style of the cans in the packaging line (the cans then being bound to each other by the lengths of plastic sheet that do not adhere to them). This means that processes of this kind are limited to production of arrays consisting of a fixed number of cans (packs of six, twelve, and the like) but cannot be used to cover a single can at a time.

Disclosure of the Invention It is an object of the present invention to overcome the disadvantages mentioned above by providing a method and a device for making and applying a covering element on beverage cans and similar containers. The method disclosed is extremely simple and economical, can be applied to single containers and is therefore independent of the number of articles in the array required and gives an economical and practical end product.

Another object of the invention is to provide a device which implements the above method and which can be added to the container

production lines (including existing production lines) at a minimum cost for manufacturers, while allowing high production speed in such a way as not to negatively affect the productivity of the production lines.

Further characteristics of the invention, in accordance with the above-mentioned aims, are set out in the claims below and the advantages more clearly illustrated in the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment without limiting the scope of the invention, and in which: -Figures 1 to 4 are schematic perspective views, with some parts cut away in order to better illustrate others, of four stages of the method for making and applying a covering element on beverage cans and similar containers; -Figure 5 is a schematic side view, with some parts cut away in order to better illustrate others, of the device that implements the method illustrated in Figures 1 to 4; -Figure 6 is a scaled up side detail view of the device illustrated in Figure 5; -Figure 7 shows the same detail as that in Figure 6 in a view from R and with some parts cut away in order to better illustrate others; -Figure 8 is a schematic top plan view, with some parts cut away in order to better illustrate others, of the device illustrated in Figure 5; -Figure 9 is a scaled up view of a detail from Figure 7; -Figure 10 is a perspective view of a container with a cover made using the method and device disclosed; -Figure 11 is a scaled up, schematic front view of a detail from Figure 8, showing second cutting means.

With reference to the accompanying drawings listed above, and in particular Figures 1 to 4, the method disclosed is used for making and applying a covering element 1 on containers 2, such as beverage cans or tins, each having a top surface 3 and a lower surface or base 4 which rests on a feed belt surface 5. The containers 2 illustrated in the accompanying drawings are, purely by way of example, cylindrical beverage cans. It is obvious that, without losing in originality, the method and device disclosed can be applied to containers of any shape for other types of products that

need to be protected by a covering element.

The method forming the subject matter of the present invention comprises the following steps: -positioning with suitable means 7 a web 6 of single-sided adhesive film, that is to say, of a material having one adhesive surface 6a, over the top surface 3 of at least one container, so as to bring into contact with said top surface 3 the surface 6a whose adhesive means may be spread on the web during the process by a suitable feeder or may already be present on the web; -cutting from the web 6 a single sheet 8, using suitable cutting means 9 and 10, one side of the single sheet being at least as large as the top surface 3; -causing the single sheet 8 to adhere permanently to and thus seal the top surface 3 by using suitable means 11 to press the sheet down.

In the steps described above, reference is made to at least one container 2 but, for convenience, the description from here on will refer to a plurality of containers 2 in order to better outline both the method and the device disclosed.

As shown in Figure 5, the step of positioning the web 6, is preceded by a step of unwinding the web 6 from a roll 12.

As will be described in more detail below, the cutting step makes a single sheet 8 that is larger in size than the top surface 3. In the embodiment illustrated, the sheet 8 is substantially quadrangular since the step of cutting it is effected by cutting the web 6 lengthways and crossways relative to its unwinding direction.

In the next step, as described above, the top of the can is covered by the single sheet 8 by making the single sheet 8 adhere to the top surface 3 and to an area around it, which in the embodiment illustrated, is a cylindrical portion of the body of the can.

Figures 1 to 4,5 and 8 show a plurality of containers 2 arranged in rows Fl, F2... Fn moving along a feed direction A side by side on a feed belt 5.

In this case, the method envisages, in more detail, the following steps: -unwinding from the film roll 12 a length of the web 6 having a surface 6a on which there are adhesive means ; -positioning with the means 7 the web 6 of single-sided adhesive film on the top surfaces 3 of the containers 2 in such a

way that the adhesive surface 6a comes into contact with each of the top surfaces 3 (see Figure 1); -performing a first cut on the web 6 lengthways in at least two or more directions parallel to the feed direction A, using suitable first cutting means 9, in such a way as to make a corresponding number of separate, parallel strips 6b, 6c,... 6n, each in contact with the top surfaces 3 of the containers 2 of a row F1, F2,... Fn (see Figure 2); -performing a second cut on each of the separate strips 6b, 6c,... 6n crossways relative to the feed direction A, using suitable second cutting means 10, in such a way as to make for each container 2 one single sheet 8 at least as large in size as each top surface 3 of each container 2 and in contact with the top surface 3 itself (see Figure 3); -causing each single sheet 8 to adhere permanently to and thus seal each top surface 3 by using suitable means 11 to press each sheet down (see Figure 4).

As shown in Figures 5 to 8, the method described above can be implemented, for example, by a device that comprises the following parts located along a feed belt 5 moving in a feed direction A: -a station 7 for feeding the web 6 of single-sided adhesive film and designed to position the web 6 in such a way that the adhesive surface 6a is in contact with the top surfaces 3 of the containers 2; -means 9 and 10 for making from the web 6 of film being fed single sheets 8, each of which is at least as large as the top surfaces 3; and -means 11 for pressing the single sheets 8 over the top surfaces 3 in such a way as to cover and seal the top surfaces themselves.

Looking more closely at the constructional details of the device, the feed station 7 comprises the above mentioned roll 12 of film to be fed to the belt 5, and means 13 for unwinding the film web 6 and positioning it over the top surfaces 3 of the containers 2.

The unwinding means 13 may (see Figure 5) consist of a plurality of tensioning rollers 13r and a conveyor 13n that is guided up to the point of contact with the containers 2 moving forward on the feed belt 5. If the film is of a type that already has adhesive

means on its surface 6a, the station 7 has no other components. On the contrary, if it is necessary to spread adhesive on the surface 6a, means 14 are envisaged for spreading the adhesive on the surface 6a prior to the positioning of the surface itself over the top surface 3 (in Figure 5, the means 14 are represented by a block since they are of a type well known to experts in the trade).

Further means 13t are envisaged for cutting the web into suitable lengths depending on the style and number of the containers 2 moving along the feed belt 5. Such means 13t may consist of a knife acting perpendicularly to the direction of film feed.

Between the station 7 that feeds the film web 6 and the above mentioned means 9 and 10 that make the single sheets 8, there may be means 21 for the pre-adhesion of the web 6 on the top surfaces 3 of the containers 2 so as to ensure better contact between the web 6 and the containers 2.

The pre-adhesion means 21 may consist of a third, motor-driven roller 22 that turns about a horizontal axis, mounted transversally to the feed belt 5, and that is designed to press the web 6 down onto the top surfaces 3.

The above mentioned means 9 and 10 that make the single sheets 8 are located downstream of the feed station 7 relative to the feed direction A.

The means 9 and 10 comprise a first unit 9 for cutting the web 6 lengthways parallel to the feed direction A so as to make a separate strip 6b, 6c,... 6n for each of the rows Fl, F2,... Fn (see also Figure 2), and a second unit 10 for cutting the separate strips 6b, 6c,... 6n crossways relative to the feed direction A and designed to make for each container 2 a single sheet 8 that is at least as large as the top surface 3 of the containers 2 (see Figure 3).

Looking in more detail, the first, lengthways cutting unit 9 (see Figures 5 and 8) is located upstream of the second, crossways cutting unit 10 relative to the feed direction A of the containers 2.

The first, lengthways cutting unit 9 consists of a first motor- driven roller 15 synchronised with the feeding of the rows of containers 2 and rotating about a horizontal axis. The first roller 15 is mounted transversely over the belt 5 and is equipped with a plurality of cutting rings 16, the latter being rotatably connected with the first roller 15 and protruding from the roller itself in

such a way that they can cut the film into separate strips.

Obviously, the number of cutting rings depends on the number of rows on the feed belt 5.

Again with reference to Figures 5 and 8, the second cutting unit 10 consists of a second motor-driven roller 17 synchronised with the belt 5 and rotating about a horizontal axis. The second roller 17 is also mounted transversely over the belt 5 and is equipped with a plurality of knives 18, the latter being equally spaced around the outer surface of the second roller 17.

Each knife 18 may protrude radially from the second roller 17 and extends along the full length of the second roller. Obviously, the knife 18 spacing, that is to say the distance between two consecutive cuts, depends on the size of the containers 2 on the feed belt 5.

Alternatively, each knife 18 may move in and out of the roller 17 radially (see Figure 11) and may be equipped with control means 18a (for example a cam fitted coaxially in the second roller 17) designed to push the knife 18 out of the second roller 17 in a radial direction when it is at the area between two adjacent containers 2 and to retract the knife into the second roller after cutting the film (see arrows F18 in Figure 11).

The above mentioned means 11 for pressing the single sheets 8 comprise a motor-driven drum 19 that rotates about a horizontal axis and that is mounted transversely over the belt 5.

The drum 19 is located downstream of the two cutting units 9 and 10 relative to the feed direction A and has on its surface a set of impressions 20 that match the shape and size of the top surfaces 3 of the containers 2 and of the part of the container body adjacent to the top surface.

In practice, the drum 19 has a plurality of impressions 20 made in it (which, in the detail of the embodiment illustrated in Figures 6 and 7, are partly cylindrical in shape) located one after the other right around its surface and side by side to form a plurality of rows running its full length. Again the number of the rows of impressions 20 depends on the number of container rows on the belt 5.

As shown in Figure 6, when the containers 2 move under the drum 19 each impression 20 engages the top of a container 2 in such a way as to press the corresponding single sheet 8 onto the container 2

causing it to adhere to the top surface 3 and on the part of the container 2 body adjacent to the top surface 3. This is accomplished through the relative motion between the drum 19 and the containers 2.

Advantageously, each impression 20 (see Figure 9) may have a break 20a in its perimeter, extending in a radial direction and used to make a protrusion 8s on the sheet 8 (see Figure 10) by folding a corner portion of it onto itself. This protrusion forms a pull element used by the consumer to remove the sheet 8 from the top surface 3.

Up to now, the invention has been described with reference to containers 2 of cylindrical shape with a tapered upper portion to allow the single sheet 8 to be cut. To cover containers with a completely straight outer surface even at the upper portion to be covered (for example, containers of parallelepipedal shape), spacing means 30 and 31 (illustrated schematically in Figure 2) may be inserted between the containers 2 to create sufficient space between them both lengthways and crossways relative to the feed direction A.

This space allows the film to be cut in such a way that each single sheet 8 extends beyond the top surface of each container 2 on all sides.

Figure 10 shows the finished container covered using the method and device disclosed. The container 2 has on its top surface 3 the sheet 8 of single-sided adhesive film which covers the top surface itself and which extends downwards over a part of the body of the container 2. The sheet 8 also has a protrusion 8s extending outwards radially from the top surface 3 to form a pull element used by the consumer to remove the covering sheet 8 when he/she wants to open the container 2.

In the embodiment illustrated in Figure 10, the protrusion 8s has the shape of an ear formed by crimping a portion of the covering sheet 8.

The method and device disclosed therefore accomplish economy and ease of production and provide protection of the clean condition of the drinking area of the container with a covering element that is not only economical and safe for consumers but also reliable and effective in sealing the container top.

In addition, the device is structured for flexibility and can be adapted to suit a wide range of production requirements, that is to

say, it can be used on a wide variety of container types, sizes and styles. Moreover, the layout of the device is extremely simple and compact. The device can be applied at very reasonable cost not only to new production. lines but also to existing lines.

The invention described can be subject to modifications and variations without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements.