Method and machine for making intermediate component of single use capsules for beverages

1. Method for making intermediate components ( 11 ) of single-use capsules ( 1 ) for extraction or infusion beverages including a rigid body ( 2 ), cup-shaped and featuring a bottom ( 3 ) and an upper aperture ( 4 ) with a rim ( 7 ), and a filtering element ( 8 ) engaging the upper aperture ( 4 ) and configured to present a concavity within the rigid body ( 2 ) so as to define a chamber ( 5 ) adapted to contain a dose (D) of product, the rigid body ( 2 ) being impermeable to beverage, the filtering element ( 8 ) being effective as a filter for liquid, the method comprising the following steps, in sequence:

feeding a plurality of rigid bodies ( 2 );

positioning a first strip (S 1 ) of thermoformable filtering material above at least one of the rigid bodies ( 2 );

joining the first strip of thermoformable filtering material to the rim of the rigid body ( 2 ) at an upper surface of the rim that defines a joining zone wherein the portion of the filtering material which is joined is the joined portion of filtering material; and

forming the filtering element ( 8 ) by plastic deformation to define the chamber ( 5 ) adapted to contain the dose (D) of product, wherein the step of joining precedes the step of forming and wherein the step of forming comprises:

a first sub-step of thermoforming an annular zone ( 8 a ) of the filtering element ( 8 ), the annular zone ( 8 a ) being the portion adjacent and internal to the joined portion of filtering material; and a second sub-step of thermoforming a central zone of the filtering element ( 8 ) until the filtering element ( 8 ) achieves a shape of the chamber ( 5 ) in its final configuration,

wherein the central zone is different from and interior to the annular zone ( 8 a ) and wherein the second sub-step is separate from and subsequent to the first sub-step.

2. Method according to claim 1 , wherein the step of feeding provides for feeding the rigid bodies ( 2 ) singly.

3. Method according to claim 1 , wherein the step of feeding provides for feeding the rigid bodies ( 2 ) in form of a second strip (S 2 ) of thermoformed alveolate material.

4. Method according to claim 1 , including a step of cutting, downstream of the step of forming, to cut at least the first strip (S 1 ).

5. Method according to claim 1 , including a step of cutting of the first strip between the step of joining and the step of forming.

6. Method according to claim 1 , wherein said step of joining is achieved by sealing, or hot or cold gluing, or by means of ultrasounds.

7. Method according to claim 1 , wherein the first sub-step is completed before the second sub-step is commenced.

8. Method according to claim 1 , wherein the first sub-step is performed by a first or pre-forming punch ( 14 ) which includes a heated ring element.

9. Method according to claim 8 , wherein the heated ring element has an external contact surface which is inclined and configured for thermoforming and flaring the annular zone ( 8 a ).

10. Method according to claim 1 , wherein the second sub-step is performed by a second punch ( 15 ) which includes a forming head which has an external contact surface which is configured to contact and thermoform the central zone of the filtering element ( 8 ) to define the chamber ( 5 ).

11. Method according to claim 10 , wherein the first sub-step is performed by a first punch ( 14 ) which includes a heated ring element, and wherein the first punch ( 14 ) and the second punch ( 15 ) are coaxial.

12. Method according to claim 11 , wherein the second punch ( 15 ) is dimensioned and operated to slide within the first punch ( 14 ).

13. Method according to claim 10 , wherein the first sub-step is performed by a first punch ( 14 ) which includes a heated ring element, and wherein the second punch ( 15 ) is arranged downstream of the first punch ( 14 ) along an advancing direction (A).

14. Method according to claim 10 , wherein the second punch ( 15 ) does not contact the annular zone ( 8 a ).