Precharged ground coffee capsule, method for its production and apparatus for implementing said method

Taught herein are a precharged ground coffee capsule comprising a polygonal cross-section container body made of a liquid-impermeable material, the container body having an open end and a large axial opening formed in a bottom wall of the container body, two walls made of a liquid-permeable material being arranged on the open end and at the bottom wall respectively, the liquid-impermeable material comprising a metallic material support layer and a thermoplastic material layer, the thermoplastic material layer facing the interior of the container body, the permeable walls being coupled to the container body through the thermoplastic material layer, an outwardly projecting radial flange being provided at the open end of the container body; a method for producing the capsule; and an apparatus for implementing the method.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to precharged ground coffee capsules, a method of production thereof, and an apparatus for implementing such method

2. Description of the Related Art

Precharged ground coffee capsules are gaining more and more importance in the market since they are easy and practical to be used, and because each single ground coffee dose assures for a better maintenance of coffee fragrance. Precharged capsules can be projected for both espresso coffee machines and moka type coffee machines or the like; in the last years, the shape and structure of the different capsules have been widely developed because of different use and preservation requirements.

In the choice of the materials and structure to be imparted to a precharged capsule, a considerable problem is to determine a right balance between strength and effectiveness in use; in other terms, if water-permeable materials such as filter paper, non-woven fabric and the like allow for a good utilization of the capsule on one hand, they have considerable drawbacks regarding to preservation and positioning of the capsule in a capsule-holder on the other hand.

The majority of commercially available precharged capsules follow two main veins: in one case, the main container body is made of a plastic material while, in the other case, the container body is made of a metallic material. In either cases, it is necessary to adopt special measures to solve several problems that hamper the production and/or use of the different precharged capsules. For example, capsules with a container body made of a plastic material can comprise certain materials which are adapted to resist the heat load, and generally they have to be molded, filled and than covered with layers of a water-permeable material. Capsules made of a metallic material are easy to be formed and require a very short thickness on one hand; on the other hand, they are difficult to be matched with a suitable filtering material, and they also have a drawback to react with ground coffee and speed up the development of rancidity. In most cases, in order to achieve good results from the point of view of preservation and preparation of a coffee brew, the device used with the precharged capsule has to be modified to an extent which can also be considerable, so that the precharged capsule can be pierced or otherwise fluid-communicated with means for supplying hot water under pressure and/or means for dispensing the ground coffee brew.

An aim of the present invention is to provide a precharged ground coffee capsule which does not compromise the preservation state of ground coffee while being of a simple and inexpensive construction, such capsule being easy to be used with both common espresso coffee machines and “moka type” coffee machines without any special modification to the coffee machine used with the precharged capsule.

Another aim of the present invention is a method for producing ground coffee precharged capsules, which method can be carried out in a simplest way using a single operating unit without transferring semi-finished products from a machine to another one.

Another aim of the present invention is to provide an apparatus for implementing such new method of production.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is a precharged ground coffee capsule comprising a polygonal cross-section container body, and preferably a circular cross-section container body, made of a liquid-impermeable material, said container body having an open end and a large axial opening formed in a bottom wall of said container body, two walls made of a liquid-permeable material being arranged on said open end and at said bottom wall respectively; said liquid-impermeable material comprises a metallic material support layer and a thermoplastic material layer, said thermoplastic material layer facing the interior of said container body, said permeable walls being coupled to said container body through said thermoplastic material layer, an outwardly projecting radial flange being provided at said open end of said container body.

Another object of the present invention is a method for producing a ground coffee precharged capsule, said method comprising the steps of:feeding a continuous ribbon of liquid-impermeable material and punching a cavity, thus forming a container body;shearing an opening in the bottom wall of said cavity;feeding a continuous ribbon of liquid-permeable material and shearing a piece of liquid-permeable material, said piece of liquid-permeable material being disposed in the bottom of said cavity;heat-welding said piece of liquid-permeable material to the bottom of said cavity;filling the said cavity with ground coffee;pressing said ground coffee into the said cavity;feeding a ribbon of liquid-permeable material and shearing a piece of the said material, said piece being disposed over said filled cavity;heat-welding said piece and liquid-permeable material to the top of said cavity; andshearing said liquid-impermeable material and releasing the so-formed precharged ground coffee capsule.

Another object of the present invention is an apparatus for producing precharged ground coffee capsules, said apparatus comprising:feeding means for feeding a continuous ribbon of liquid-impermeable material;punching means for punching a cavity in said continuous ribbon;shearing means for shearing an opening in the bottom of said cavity, anddischarging means for discharging a corresponding scrap;feeding means for feeding a continuous ribbon of liquid-permeable material;shearing means for shearing a piece of liquid-permeable material, and positioning means for positioning said piece of liquid-permeable material within said cavity;welding means for welding said piece of liquid-permeable material to said cavity;feeding means and dosing means for feeding and dosing ground coffee in said cavity respectively;pressing means for pressing a coffee dose into said cavity;feeding means for feeding a continuous ribbon of liquid-permeable material;shearing means for shearing a piece of liquid-permeable material, and positioning means for positioning said piece of liquid-permeable material over said cavity filled with said pressed ground coffee dose;welding means for welding said piece to said liquid-impermeable material; andshearing means for shearing said liquid-impermeable material, and releasing means for releasing the so-formed ground coffee precharged capsule.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

InFIG. 1, reference numeral1denotes a precharged ground coffee capsule according to the present invention; said capsule comprises a substantially frustoconical shaped container body101having an open end. Said body101is made of an impermeable material such as, for example, a sheet metal and particularly aluminium, and it has a large axial opening111formed in a bottom wall thereof. The body101has a plastic material layer on the inner side thereof, and a filtering permeable material301is heat-welded at an opening111formed in the bottom wall of the internal cavity151of the body101through such plastic material layer. Similarly, a radial flange121projecting outwardly from the trailing edge of said cavity151enables such filtering permeable material layer401to be heat-welded; a ground coffee dose2is filled within the capsule1.

FIG. 2schematically shows the steps of a first embodiment of the method for producing precharged ground coffee capsules according to the present invention; a roll1100feeds a sheet metal ribbon100coated with a thermoplastic material layer to a station10, where the cavity151of the container body101is punched. The bottom wall of the container body101is sheared in a subsequent station20, then the filtering permeable material300fed by the roll1300is sheared in a subsequent station30. Subsequently, the filtering material is welded to the bottom of the body101in station40, then the cavity151is filled with ground coffee in station50; after pressing of the ground coffee in station60, a filtering material layer is sheared from a ribbon400fed by a roll1400(station70). In the next step, the filtering material layer is welded to the top trailing edge of the body101in station80, the ribbon around the body101is sheared in station90, and finally the so-formed capsule1is released.

FIG. 3shows the first three steps of the method according to the present invention, along with their corresponding operating stations; station10comprises a punch11and a die13which are provided with a punch head12and a cavity14respectively, and they co-operate to punch the cavity151of the container body101from the continuous ribbon100. In the next station20, a shearing punch21and a matrix23co-operate to shear the bottom of the cavity151of the body101, resulting in an opening111and a corresponding scrap131. The shearing punch21is provided with a shearing head22which co-operates with an axial through-bore24of the matrix22; the scrap131is discharged through a discharge duct25which is coaxial with the bore24. In the next step, a shearing punch31and a matrix33co-operate to shear a filtering permeable material piece301from the ribbon300. A shearing head32of the shearing punch co-operates with an axial through-bore34of the matrix, and the filtering permeable material piece301is discharged to the bottom of the cavity151, over the opening111, through a duct35.

FIG. 4shows the next three steps of the method according to the present invention; station40comprises a punch41and a die45. The punch is provided with a welding head42comprising heating means43and an annular projection44; similarly, the die45is provided with a cavity46comprising heating means47and an annular projection48in the bottom thereof. By heating the annular projections of the welding head42and of the cavity46respectively, the thermoplastic material layer201is molten and makes the permeable material layer301to be fixed to the edge of the opening111. Subsequently, the container body101is moved to station50, which houses a coffee grinding assembly51provided with a dosing hopper52which discharges a ground coffee dose2into the cavity151of the container body101. The dose2is pressed by pressing means61, the body101being positioned in a cavity63of a support62(station60).

FIG. 5shows the last three steps of the method according to the present invention; station70houses a shearing punch71which co-operates with a matrix73to shear a permeable material piece401from the ribbon400through a shearing head72; the permeable material piece401falls through a conduit75across the matrix and onto the top of the container body101filled with the previously pressed ground coffee dose2. Subsequently (station80), a welding head81provided with heating means82and an annular projection83co-operates with the cavity of a die84whose trailing edge comprises an annular projection87under which heating means86are provided. Similarly to station40, the filtering permeable material is also welded to the metallic support by exploiting the thermoplastic character of its inner coating201. In the last step of the method according to the invention (station90), a shearing punch91co-operates with a matrix93to separate the precharged capsule1from the metallic foil ribbon100. A shearing head92co-operates with an axial bore94of the matrix to carry out the cutting step, and the capsule1is released through a conduit95of the matrix itself. The capsule is now provided with the radial flange121, as already previously described referring to FIG.1, and this radial flange enables the capsule to be sealed into the device used for preparing a coffee brew, whether it is an espresso coffee machine or a moka type coffee machine, or the like.

FIG. 6shows a variant embodiment of the method according to the present invention; in this variant embodiment, after welding of the permeable material piece301to the edge of the opening111in station40(seeFIG. 2), the container body101is separated from the metal sheet ribbon100before being filled in station50as previously described. That is, a station140is added, and this station comprises a shearing punch141having a shearing head142, and a matrix143having a through-bore144, and the shearing head142co-operates with the through-bore144to shear the container body101from the ribbon100. Subsequently, the container body101is dropped onto a transport line500which can be of any suitable construction; the subsequent stages are substantially the same as those previously described herein except that, of course, the container body is not transported by the same metal sheet from which said body was obtained in the first station (station10, seeFIG. 2). Also note that, in order to make the transportation of container body101easier, the radial flange161obtained by the shearing step in station140is considerably larger (i.e. about twice) than the flange131obtained at the end of processing.

In both embodiments of the method according to the invention, the so-produced capsules can be subsequently treated according to per se known methods, which are not illustrated and described herein in further detail, to enhance their preservation. Preferably, single capsules will be packaged in vacuo or under an atmosphere of an inert gas such as, for example, nitrogen, using a suitable packaging material.

The precharged capsule according to the present invention solves several problems affecting precharged capsules known in the previous art; first, due to its functional simplicity, it can be easily used with different types of devices adapted to prepare coffee brews, since it simply and only needs means for supplying water and means for gathering the coffee brew. Furthermore, the capsule is structurally robust, and this feature assures its integrity and makes its storage considerably simple. Another important aspect is provided by the construction structure of the capsule. The plastic material layer avoids a direct contact between ground coffee and metal, which is detrimental for both. Finally, the use of an inner layer of plastic material allows for a simple coupling with the filtering permeable material during the assembly procedure. The shape of the container body can be the shape which is most advantageously adapted to the process for production thereof, frustoconical and cylindrical shapes are preferred, but the container body can also have a polygonal section, e.g. the shape of a frusto-pyramid with a regular or irregular polygonal base.

The method according to the present invention has several clear advantages from the process economy point of view; indeed, the whole process is carried out in one apparatus which can be made extremely compact, and the process system is continuous, resulting in a high yield. As for the first variant embodiment, it is completely clear that using the metal sheet ribbon100, from which the container body101is obtained, as process transport line considerably simplifies the process. As for the second variant shown inFIG. 5of the accompanying drawings, it is necessary to consider an aspect observed during the study which led to the present invention. It was noted that the “slow” step of the process was that of station50, i.e. the step where the container body101is filled with the ground coffee dose; accordingly, it was considered that, by separating the container body from the metal sheet ribbon in a step just before this filling step, it was possible to obtain two different lines for the subsequent steps, resulting in an increased yield of the apparatus.

Finally, as for both variant embodiments of the method according to the present invention, using a metallic foil provided with a thermoplastic material layer considerably simplifies the fixing operations for the permeable material, which can be consequently chosen from materials such as paper, a non-woven fabric made of natural fibers, or the like.