Capsule-sealing system with improved sealing head

Abstract

According to the present disclosure, a system for capsule sealing using an improved sealing head for applying a top to a can is contemplated. The improved sealing head is contemplated as being capable of producing a sealed can having greater adhesion and strength in at least one area of the can edge, and a weaker adhesion in the remaining area of the can edge, in order to simplify opening and to reduce any requirements for the use of non-metallic adhesives.

Claims

1. A sealing head of a capsule-sealing machine for applying a covering capsule on a top surface of a can to be encapsulated, the can comprising an edge and an opening covered by a tab for dispensing the contents of the can, the sealing head comprising: first and second circular sealing sectors being radially positioned around an axis of vertical motion of the sealing head, at least one of the first and second circular sealing sectors being provided with a conformed lower edge, the conformed lower edge being operative to interpose between the covering capsule and a can edge proximal area as they approach together during the operation of the capsule-sealing machine; first and second elastic means being coupled with said corresponding first and second sealing circular sectors for counteracting axial movement of the said circular sealing sectors as the covering capsule and the can edge proximal area approach together during operation of the capsule-sealing machine; heating means being connected to said first and second circular sealing sectors, the heating means being operative to heat the first and second circular sealing sectors to a given sealing temperature; wherein the sealing head is configured such that during the operation of the capsule-sealing machine, the first sealing circular sectors and the first elastic means are configured to apply a higher pressure on a first circumferential arc zone of the can, and the second sealing circular sectors with the second elastic means are configured to apply a lower pressure on a second circumferential arc zone of the can to achieve a differential adhesion between the covering capsule and the first and second circumferential arc zones on the first and second circumferential arc zones such that the capsule is separable from the second circumferential arc zone to open the can while remaining adherent to the first circumferential arc zone.

2. The sealing head according to claim 1, wherein the first and second circumferential arc zones are angularly arranged such that an opening of the can is facing said second circumferential area of the can.

3. The sealing head according to claim 1, wherein the first and second elastic means comprise springs, the first elastic means having a greater stiffness than the second elastic means, the first circular sealing sector being configured to align, during operation of the can-sealing machine, with a first can edge proximal area opposing the can opening, and with the second circular sealing sector being configured to align, during operation of the can-sealing machine, with a second can edge proximal area facing the can opening.

4. The sealing head according to claim 1, wherein the sealing head is incorporated within a capsule sealing machine for applying a covering capsule on a top surface of a can to be encapsulated, the capsule sealing machine additionally comprising a pusher having a support surface for supporting the can to be encapsulated, and a suction cup for holding the covering capsule.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further purposes, features and advantages of the present invention will be clear from the following detailed description of a preferred form of application of the invention, provided for explanatory and non-limiting purposes only with a variant thereof by means of the appended figures, wherein:

(2) FIG. 1 represents a schematic upwards view of a longitudinally sectioned sealing head according to the invention and other parts of a capsule-sealing machine according to the invention, the machine depicted in a processing station thereof for capsule-sealing a can;

(3) FIG. 2 represents a perspective view of a can obtained by processing the capsule-sealing machine of FIG. 1;

(4) FIGS. 3 and 4 represent schematic views according to an A-A section of FIG. 1 respectively of some details of the sealing head of FIG. 1 and of a variant of the same head according to the invention.

DETAILED DESCRIPTION

(5) According to the above figures, a sealing head of a capsule-sealing machine for applying a covering capsule or capsule 1 to an upper surface 3s of a can 3 in a processing station of the same machine, as schematically illustrated in FIG. 1, is indicated by 10 in its entirety. The can 3 is of a type comprising an upper edge 3b and an opening 3a covered by tab 31 for dispensing the contents of the same can 3.

(6) The sealing head 10 and the capsule-sealing machine are for example of a type as illustrated and described in patent application N. ITBO22020325, the description of which, in particular with regards to FIGS. 3 and 8 of the said document, is deemed to be incorporated in the present description for the sake of completeness.

(7) More in detail, the sealing head 10 is of a type comprising: a plurality of circular sealing sectors, indicated in their entirety by 20, arranged around a vertical movement axis X of the same sealing head 10 and capable of interfering, through one of their conformed lower ends 28 and the interposed covering capsule 1, with a circumference 3i of the upper edge of the can 3b when the can 3 approaches the sealing head 10 during a processing phase in an capsule-sealing station of the capsule-sealing machine, elastic means, indicated by 30 in their entirety, in coupling with the circular sealing sectors 20 for the counteracted axial movement of the same circular sectors 20 when they come into contact with the covering capsule 1 and with the edge surrounding the can 3i; heating means, for example a pair of electrical resistors with a temperature sensing probe 12, connected to the circular sealing sectors 20 and suitable for bringing them to a given and fixed sealing temperature.

(8) In the example, the elastic means comprise a plurality of helical springs 30 guided by first guide pins 14 integral with a central body 11 of the sealing head 10 and by second guide pins 16 integral with the circular sealing sectors 20. In this way, said circular sectors 20 are integral with the central body 11 and cannot rotate with respect to the same.

(9) FIG. 1 schematically illustrates, omitting details not necessary for understanding the invention, the capsule-sealing machine in correspondence with one of its can capsule-sealing stations 3 with the relative covering capsule 1. Note how, in an operative condition of application of the covering capsule 1 on the same can 3, they are coaxially aligned to the vertical axis X, in order from bottom to top: a pusher 4 provided with a support surface 6 for the can 3 to be capsule-sealed; the can 3 to be capsule-sealed; the covering capsule 1, which is connected to a suction cup device 8 for its correct positioning to cover the surface of can 3s to be capsule-sealed, the sealing head 10 of the type described above.

(10) Briefly, the operation of the capsule-sealing machine provides that, in the operating condition described above, the pusher 4 is driven to move from bottom to the top, in order to meet the can 3 with its supporting surface 6 and push the same upwards in the direction of the sealing head 10, with its upper surface 3s and relative upper edge 3b to meet the covering capsule 1 and then go to flow inside the sealing head 10, interfering with the circular sectors 20. The capsule 1 then adheres with one of its central parts 1c to the upper surface 3s by means of the suction cup 8, with its peripheral parts 1p to the conformed lower ends 28 of the circular sectors 20, which are heated to a certain sealing temperature by means of the heating means 12. When the edge of the can 3b with its surrounding 3i pushes the peripheral parts of the capsule 1 against the circular sectors 20, it meets the resistance of the elastic means 30 which thus exert a pressure force proportional to their stiffness on correspondent circumferential arc zones of edge 3i. Therefore, one of such zones, i.e. that corresponding to lower stiffness springs, shows a lower adhesion with the capsule and the other of such zones, namely that corresponding to higher stiffness springs, shows a higher adhesion with the capsule.

(11) In this respect, the applicant has observed that it is possible to realize a sealing of the capsule 1 on the can 3 advantageously more or less strong and adhesive depending on their greater or lesser stiffness of the elastic means 30. This concept constitutes the focal point of the present invention.

(12) Therefore, a peculiarity of the invention is that the sealing head comprises elastic means with different stiffnesses, for example comprising of helical elastic springs with decreasing stiffness, in particular progressively decreasing from 31 to 36 when respectively coupled to the circular sectors 21-26 as illustrated in FIGS. 3 and 4, wherein 31 identifies the elastic spring with greater stiffness coupled to the circular sector 21 positioned in correspondence of a distal point D to an edge of the can adjacent to the opening 3a, in particular to the circular sector positioned in correspondence of the furthest point D from the edge of the can adjacent to the opening 3i. Preferably, the elastic spring with higher stiffness is located in an angular position other than that of a mean axis of the opening so that the latter is not facing the circular sector on which the spring with higher stiffness acts.

(13) Advantageously, as already explained, the greater stiffness of the spring 31 means that the conformed lower end 28 of the circular sector 21 exerts a greater compression force when far from the edge of the can adjoining the opening 3i, thus realising a seal having greater strength and stiffness than that of the other points, distancing the danger of detachment of the covering capsule 1 when a user takes it by one of its flaps 11 proximal to the opening 3a in order to be able to open the can 3 and access its contents.

(14) Elastic means, for example elastic springs 31-33 have higher stiffness when coupled to circular sectors 21-23 positioned at points distal D to an edge of the can adjoining the opening of the can 3i, lower stiffness springs 34-36 when coupled to circular sectors 24-26 positioned at points proximal P to the edge of the can adjoining the opening 3i. That is, one of the circular sectors 24-26 is facing the opening 3i and, for example, an axis of the corresponding lower stiffness spring is incident to a mean axis of the opening 3i.

(15) With reference to a variant of the sealing head 10 as illustrated in the schematic section A-A of the FIG. 4, omitting some unnecessary details of the same, the circular sectors 21-23 positioned in correspondence of distal points (D) to the edge of the can adjacent to the opening 3i have a smaller circumferential extension compared to the circular sectors 24-26 positioned in correspondence of proximal points P to the edge of the can adjacent to the opening 3i, in particular they have a progressively smaller circumferential extension.

(16) This advantageously increases the extension of areas of the sealing capsule with less stiffness and which offer less tearing resistance to a user, allowing the same to more easily detach the capsule 1 in those areas where there is access to the tab, together decreasing the extension of the areas having the sealing instead with greater stiffness thus considerably increasing the probability that the same capsule remains attached to the can.

(17) It is clear that further and numerous variations are possible for a skilled person in the art of the capsule-sealing machine having an improved type of sealing head for applying an covering capsule to the top surfaces of cans and the associated improved sealing head and can having the associated covering capsule according to the invention; just as it is clear that in its practical implementation the shapes of the illustrated details may be different and the same may be replaced with technically equivalent elements.

(18) For example, in a more sophisticated version of the sealing head, the variable stiffness spring means may comprise electronically controlled air springs, rather than other known types of mechanical spring that are equivalent to coil springs.