Method and machine for producing a single-use capsule for beverages and capsule obtained using method

1. A method for producing a single-use capsule ( 1 ) for beverages comprising a cup-shaped external rigid body ( 2 ) comprising a closed bottom ( 3 ) and a top opening ( 4 ) coupled with a filter extending, with a concave cross-section, into the body ( 2 ) to form a chamber ( 5 ) for containing a dose (D) of product, and a sheet lid ( 6 ) for closing the top opening ( 4 ) of the rigid body ( 2 ) along an external rim ( 7 ) of the body ( 2 ), characterised in that it comprises the following steps in this sequence:

positioning a flat piece ( 8 ) of filter paper over the rigid body ( 2 );

joining the flat piece ( 8 ) of filter paper along at least the rim ( 7 ) of the rigid body ( 2 );

forming the piece ( 8 ) of filter paper towards the interior of the rigid body ( 2 ) and by means of a plastic deformation of the piece ( 8 ) of filter paper to define the containment chamber ( 5 );

filling the containment chamber ( 5 ) with a dose (D) of product;

closing the chamber ( 5 ) and the external rigid body ( 2 ) with the sheet lid ( 6 ).

2. The method according to claim 1 , wherein the forming step comprises:

a first sub-step of preforming the flat piece ( 8 ) of filter paper to form a partial concavity of the piece ( 8 ) towards the interior of the rigid body ( 2 ) and

a second sub-step of complete forming of the piece ( 8 ) to define the shape of the containment chamber ( 5 ).

3. The method according to claim 2 , wherein in the first, preforming sub-step at least a peripheral annular zone ( 8 a ) of the piece ( 8 ) of filter paper close to the rim ( 7 ) of the rigid body ( 2 ) is plastically deformed to stretch said peripheral annular zone ( 8 a ).

4. The method according to claim 2 , wherein in the second sub-step of complete forming of the piece ( 8 ) of filter paper, at least a central portion of the piece ( 8 ) of filter paper is affected.

5. The method according to claim 1 , wherein forming of the piece ( 8 ) of filter paper is achieved by means of heat transfer.

6. The method according to claim 1 , wherein the step of positioning the flat piece ( 8 ) of filter paper comprises a step of cutting the piece ( 8 ) of filter paper from a continuous strip (S) of filter paper, so as to obtain a piece ( 8 ) matching a top surface of the external rigid body ( 2 ).

7. The method according to claim 1 , wherein the step of positioning the piece ( 8 ) of filter paper comprises:

a step of cutting the piece ( 8 ) of filter paper from a continuous strip (S) of filter paper, so as to shape it to match the top surface of the external rigid body ( 2 ), and

a step of moving the piece ( 8 ) of filter paper obtained by cutting onto the top opening ( 4 ) of the external rigid body ( 2 ).

8. A machine for producing a single-use capsule for extraction beverages, comprising at least:

a conveyor ( 9 ) for conveying cup-shaped external rigid bodies ( 2 ), comprising a closed bottom ( 3 ) and a top opening ( 4 ), for moving them one after another in a direction of feed (A); and

feed means ( 10 ) for feeding flat filter paper and designed to position the filter paper along at least one stretch of the feed line (A);

characterised in that the machine also comprises, along the direction of feed (A):

cutting units ( 11 ) for cutting the filter paper to obtain a flat piece ( 8 ) of filter paper matching a top surface of the rigid body ( 2 );

joining means ( 12 ) for perimetrally joining the flat piece ( 8 ) of filter paper on the top opening ( 4 ) of the rigid body ( 2 ) defined by a top rim ( 7 );

forming means ( 13 ) for forming the flat piece ( 8 ) of filter paper joined to the rigid body ( 2 ), said forming means being positioned downstream of the joining means ( 12 ) for perimetrally joining the flat piece ( 8 ) of filter paper relative to the direction of feed (A), and acting on the flat piece ( 8 ) of filter paper so as to plastically deform the piece ( 8 ) of filter paper towards a interior of the rigid body ( 2 ) to define a chamber ( 5 ) for containing a dose ( 0 ) of product inside the rigid body ( 2 ).

9. The machine according to claim 8 , wherein said forming means ( 13 ) comprise:

a first punch ( 14 ) for preforming the flat piece ( 8 ) of filter paper and designed to stretch at least a peripheral annular zone ( 8 a ) of the piece ( 8 ) of filter paper, close to the rim of the rigid body ( 2 ), according to a direction converging towards the interior of the rigid body ( 2 ) and

a second punch ( 15 ) for completely forming the piece ( 8 ) of the filter paper, operatively coupled with the first punch ( 14 ), for deforming at least the central portion of the piece ( 8 ) of the filter paper so as to define the internal chamber ( 5 ).

10. The machine according to claim 8 , comprising preforming means ( 14 ) for preforming the flat piece ( 8 ) of filter paper, interposed between the perimetral joining means ( 12 ) and the forming means ( 13 ) for forming the piece ( 8 ) of filter paper relative to the direction of feed (A), said preforming means ( 14 ) being designed to stretch at least a peripheral annular zone ( 8 a ) of the piece ( 8 ) of filter paper close to the rim of the rigid body ( 2 ) according to a direction converging towards the interior of the rigid body ( 2 ).

11. The machine according to claim 8 , comprising units ( 16 ) for receiving the piece ( 8 ) of fitter paper obtained by the cutting units ( 11 ) and designed to move the piece ( 8 ) of filter paper along the direction of feed (A) to the operating zone of said joining means ( 12 ) for perimetrally joining the flat piece ( 8 ) of filter paper to the top rim ( 7 ) of the rigid body ( 2 ).

12. The machine according to claim 11 , wherein said units ( 16 ) for receiving and moving the piece ( 8 ) of the filter paper comprise a movable platform ( 17 ) for supporting the piece ( 8 ) of filter paper and designed to release the piece ( 8 ) of filter paper onto the top surface of the rigid body ( 2 ).