enclosure sealing machine, sealing head and can equipped with a cover enclosure

Abstract

This invention relates to a sealing machine and related improved sealing heads, as well as cans equipped with corresponding covering seals. The sealing head applies a covering seal (1) to the surface (3s) of a can (3) to be sealed, the can including an edge (3b) and an opening (3a) covered by a pull ring (31) for dispensing the contents of the same can. The sealing head (10) includes: a plurality of circular sealing sectors (20), an elastic device (30), and a heating device (12). A feature of this invention is the inclusion of elastic devices (31-36) with different stiffnesses when connected to the circular sealing sectors; that is, elastic devices with higher stiffness when connected to circular sectors (21-23) positioned corresponding to a distal point (D) of the edge (3i) adjacent to the opening of the can, and elastic devices with lower stiffness when connected to circular sectors (24-26) positioned at a proximal point (P) of the can edge adjacent to the can opening.

Description

Technical Field

[0001] This invention relates to a sealing machine with an improved sealing head for applying a cover seal to the top surface of a can or covering the top surface of a can with a seal, and to an improved sealing head and a can with a corresponding cover seal.

[0002] In this document, the terms "shell" and "covering shell" are equivalent and refer to a very thin metal shell, typically made of aluminum alloy, that forms a cover or seal for a can to be packaged.

[0003] The present invention is applicable to the industrial field of can manufacturing and / or processing, which cans are typically cylindrical in shape made of thin aluminum and can hold various types of liquids, such as, for example, soft drinks, beer, rather than food, or similar items that are readily available by an opening that is radially positioned on the top surface of the can and closed by a removable pull ring. Background Technology

[0004] For hygiene reasons, the technique of covering the entire upper surface of the can, especially the area where the mouth of the user who wants to drink its contents from the can opening after removing the pull tab comes into contact with the covered seal, has been used for some time.

[0005] The technology known in this art is disclosed in patent document number US2005160698, which describes and illustrates a sealing machine for applying a seal to a can. In the sealing station of this machine, a can, moved by a rotating roller, is positioned substantially coaxially with a pusher that supports the can downwards, the seal to be applied, and a sealing head adapted to be fixedly inserted between the upper portion of the can and the sealing head. The sealing head is radially provided with a plurality of circular sectors, which are positioned such that, as the can with the seal inserted approaches the head during processing, one of its lower ends forms around the circumference of the upper edge of the can to be covered. Additionally, the sealing head is provided with elastic devices of equal stiffness, typically relative elastic springs, coupled to the individual circular sectors to resist axial movement of the circular sectors when they come into contact with the seal and the edge region of the can. More specifically, as the can enters the processing station, the machine drives a pusher that pushes the can upwards from the bottom toward the sealing head, whose circular sector has been previously heated to a given temperature by resistance within the same head to facilitate localized fusion of the seal onto the can's edge profile. Specifically, as the conformal lower portion of the circular sector contacts the covering seal and the covering seal contacts the upper surface of the can, a coupling tension is generated relative to the springs. This coupling tension, along with the given temperature, creates a surface seal of the seal over the area surrounding the can's edge. The resulting seal occurs substantially uniformly along its entire extent, causing the seal to adhere evenly to the entire circumference of the can's edge and cover the entire top surface of the can.

[0006] The applicant has identified and resolved the need in the field of can sealing machines for cans equipped with a cover seal that is difficult to completely separate from the can itself, while the risk is that when the cover seal is manually removed from its upper support to freely contact the pull ring so that the can is used and its contents are emptied, the cover seal separates from the can and falls into the environment.

[0007] The known limitation of sealing machines regarding the above-mentioned technical problems is that they apply the same adhesive force and tightness of seal around the entire periphery of the covered can, thus providing the same tear or peel strength around the entire periphery of the can's edge. Due to carelessness and / or distraction, a user wishing to access the contents of the can may easily apply a force significantly greater than that required to release the pull ring area from the can opening and its adjacent approach to the edge onto the can's protruding edge, thereby completely separating the seal from the can itself. Both the seal and the can are made of metal and are typically made of the same material (i.e., aluminum alloy) so that they can be recycled together to protect the environment. This is particularly true for seals that are uniformly sealed at the edge, as taught in US2005160698, and even more so if the seal is quite strong and the user expects to use the contents of the can quickly, making it highly likely that the seal will be completely torn off from the top edge and fall randomly into the environment and / or fall separately from the can itself. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art mentioned above, and to disclose a sealing machine with an improved type of sealing head for applying a cover seal to the top surface of a can, and related improved sealing heads, as well as a can equipped with a corresponding cover seal that enables substantial recyclability of the can and the corresponding cover seal to be recycled together.

[0009] The object of this invention is to achieve a seal with greater adhesion and strength in at least one region of the can edge and weaker adhesion in the remaining region of the can edge where the can opening is located. Therefore, the region of greater adhesion is located away from the edge adjacent to the opening.

[0010] One objective is to achieve head improvements in a fundamentally simple, inexpensive, and effective manner.

[0011] One purpose is to avoid potential contamination of the can surface by non-metallic materials, such as adhesives placed on the edge of the can to maintain the sealing seal with greater strength and adhesion.

[0012] To achieve these objectives, the present invention aims to provide a sealing machine and an improved sealing head for applying a covering seal to the top surface of a can, and a can having a covering seal thereon.

[0013] In a first embodiment, the present invention relates to a sealing head for a sealing machine. This sealing head is characterized by comprising elastic devices of varying stiffness coupled to circular sectors, and more specifically, a higher stiffness elastic device when coupled to a circular sector positioned at a distal point (i.e., in the absence of an edge of the can adjacent to the can's opening), and a lower stiffness elastic device when coupled to a circular sector positioned at a proximal point (i.e., in the presence of an edge of the can adjacent to the can's opening). Therefore, the area covering the seal corresponding to the distal point can advantageously seal to the edge of the can in a more adhesive and resistive manner compared to the area covering the seal corresponding to the proximal point of the edge adjacent to the can's opening, thereby allowing for greater tear resistance of the seal in areas away from the edge where the user utilizes the contents of the can.

[0014] Therefore, this feature eliminates the risk that a user, due to inattention and / or distraction, applies a force significantly greater than that required to completely tear the seal from the can in the area near the opening, which is slightly greater than the force required to remove the seal in the area near the opening (because the user feels less adhesion and resistance in those areas he wants to find, and is therefore more likely to apply a lighter force on the edges of the seal).

[0015] Advantageously, the solution applied is also readily applicable to known existing sealing heads, as it only requires replacing the spring with another spring of variable stiffness. Therefore, it advantageously enables the improvement of known sealing heads in a simple and cost-effective manner, making known types of sealing machines, as mentioned above, fully available, convertible, and flexible. Attached Figure Description

[0016] Further features and advantages of the invention will become apparent from the following detailed description of a preferred form of application of the invention, with the aid of the accompanying drawings. This preferred form and its variations are provided for illustrative and non-limiting purposes only, wherein:

[0017] - Figure 1 A schematic upward view showing a longitudinally sectional sealing head according to the invention and other parts of the sealing machine according to the invention, the machine being depicted for sealing cans in its processing station;

[0018] - Figure 2 Indicates processing Figure 1 A perspective view of the tank obtained by the sealing machine;

[0019] - Figure 3 and Figure 4 They represent according to Figure 1Some details of the sealing head and variations of the same head according to the invention. Figure 1 A schematic diagram of section AA. Detailed Implementation

[0020] Based on the above attached diagram, it is used as follows: Figure 1 As schematically shown, the sealing head of the sealing machine, which applies a cover or cover 1 to the upper surface 3s of the can 3 in the processing station of the sealing machine, is indicated by 10. The can 3 is of the type including an upper edge 3b and an opening 3a for dispensing the contents of the same can 3, covered by a pull ring 3l.

[0021] The sealing head 10 and the sealing housing are, for example, of the type described and illustrated in patent application N. ITB022020325. For the sake of completeness, the description of that patent application, particularly regarding the document mentioned therein, is further elaborated. Figure 3 The description in Figure 8 is considered to be incorporated into this specification.

[0022] More specifically, the sealing head 10 is of a type that includes the following items:

[0023] - Multiple circular sealing sectors, collectively indicated by 20, are arranged around the vertical movement axis X of the same sealing head 10, and are able to enter the circumference 3i of the upper edge 3b of the tank through one of its conformal lower ends 28 and the inserted covering seal 1 when the tank 3 approaches the sealing head 10 during the processing stage in the sealing station of the sealing machine.

[0024] - An elastic device, generally indicated by 30, is connected to the circular sealing sector 20 to resist axial movement of the same circular sector 20 when it comes into contact with the covering shell 1 and the edge 3i surrounding the can;

[0025] - A heating device, such as a pair of resistors having a temperature sensing probe 12, is connected to the circular sealing sector 20 and is adapted to bring it to a given and fixed sealing temperature.

[0026] In the example, the elastic device includes a plurality of helical springs 30, which are guided by a first guide pin 14 integral with the central body 11 of the sealing head 10 and a second guide pin 16 integral with the circular sealing sector 20. In this way, the circular sector 20 is integral with the central body 11 and cannot rotate relative to the central body.

[0027] Figure 1The diagram schematically illustrates the sealing machine corresponding to one of the tank sealing stations 3 and the opposing cover seal 1, omitting details unnecessary for understanding the invention. It should now be noted that, under the operating condition of applying the cover seal 1 to the same tank 3, the following items are aligned coaxially with the vertical axis X in order from bottom to top:

[0028] - A pusher 4, which is provided with a support surface 6 for the can 3 to be sealed;

[0029] -Can 3, to be sealed;

[0030] - A cover 1, which is connected to a suction cup device 8 to properly position it to cover the surface of the can 3 to be sealed.

[0031] -The sealing head 10 of the above type.

[0032] In simple terms, the operation of the sealing machine involves, under the aforementioned operating conditions, driving the pusher 4 from the bottom to the top so that the can 3 encounters its supporting surface 6 and is pushed upward in the direction of the sealing head 10, causing its upper surface 3s and opposite upper edge 3b to encounter the covering seal 1, and then enter the interior of the sealing head 10, thereby intervening in the circular sector 20. The seal 1 then uses the suction cup 8 to adhere one of its central portions 1c to the upper surface 3s, and its peripheral portion 1p to the conformal lower end 28 of the circular sector 20, which is heated to a specific sealing temperature by means of the heating device 12. When the edge 3b of the can and its periphery 3i push the peripheral portion of the seal 1 against the circular sector 20, they encounter resistance from the elastic device 30, which thereby applies pressure proportional to the stiffness of the elastic device to the corresponding circumferential arc area of ​​the edge 3i. Therefore, one of these zones, corresponding to the lower stiffness spring, exhibits lower adhesion to the enclosure, while the other zone, corresponding to the higher stiffness spring, exhibits higher adhesion to the enclosure.

[0033] In this respect, the applicant has observed that, depending on the greater or lesser stiffness of the elastic device 30, a more or less strong and adhesive seal of the casing 1 can be advantageously achieved on the can 3. This concept forms the focus of the present invention.

[0034] Therefore, a feature of the present invention is that the sealing head includes elastic devices with different stiffnesses, for example, including those with reduced stiffness, particularly stiffness such as... Figure 3 and Figure 4The diagram shows helical springs that gradually decrease in stiffness from 31 to 36 when connected to circular sectors 21 to 26, respectively. 31 indicates a spring with greater stiffness connected to the circular sector 21 located corresponding to the farthest point D of the edge adjacent to the opening 3a of the can, and particularly to the circular sector located corresponding to the farthest point D of the edge 3i adjacent to the opening of the can. Preferably, the spring with higher stiffness is located at an angular position other than the angular position of the central axis of the opening, such that the opening does not face the circular sector to which the spring with higher stiffness acts.

[0035] Advantageously, as already explained, the greater stiffness of the spring 31 means that the conformal lower end 28 of the circular sector 21 applies a greater compressive force when it is away from the edge 3i of the adjacent opening of the can, thereby achieving a seal with greater strength and stiffness than at other points. This avoids the danger of removing the cover 1 when the user pulls one of the flaps 1l near the opening 3a to be able to open the can 3 and access its contents.

[0036] The elastic device has higher stiffness, such as elastic springs 31 to 33, when connected to circular sectors 21 to 23 located at the distal point D of the edge 3i adjacent to the opening of the can, and lower stiffness, such as elastic springs 34 to 36, when connected to circular sectors 24 to 26 located at the proximal point P of the edge 3i adjacent to the opening of the can. That is, one of the circular sectors 24 to 26 faces the opening 3i, and, for example, the axis corresponding to the lower stiffness spring is incident on the central axis of the opening 3i.

[0037] For reference Figure 4 The schematic cross section AA shows a variant of the sealing head 10, omitting some unnecessary details of the same parts. Compared to the circular sectors 24 to 26 located at the proximal point P of the edge 3i adjacent to the opening of the can, the circular sectors 21 to 23 located at the distal end point (D) of the edge 3i adjacent to the opening of the can have a smaller circumferential extension, and in particular, the circular sectors have a gradually decreasing circumferential extension.

[0038] This advantageously increases the ductility of the sealing area while reducing stiffness and providing less tear resistance to the user, thus allowing the user to more easily remove the seal 1 in areas with access to the pull ring, and reducing the ductility of the sealing area rather than having greater stiffness significantly increases the probability that the same seal remains attached to the can.

[0039] It is clear to those skilled in the art that further and numerous variations of the sealing machine with an improved type of sealing head for applying a covering seal to the top surface of a can and the associated improved sealing head and the can with the associated covering seal are possible; it is only clear that in its actual specific implementation, the shapes of the details shown may differ and may be replaced by technically equivalent elements.

[0040] For example, in more complex forms of the sealing head, the variable stiffness spring device may include an electronically controlled air spring, rather than other known types of mechanical springs equivalent to helical springs.

Claims

1. A sealing head for applying a covering seal (1) to the surface (3s) of a can (3) to be sealed, the can (3) including an edge (3b) and an opening (3a) covered by a pull ring (3l) for discharging the contents of the can (3), the sealing head (10) comprising: - A first circular sealing sector and a second circular sealing sector, the first circular sealing sector and the second circular sealing sector being located around the vertical axis (X) of the same sealing head (10) and adapted to intervene in the proximal region (3i) of the can edge by the shaped lower ends (22) of the first circular sealing sector and the second circular sealing sector and the covering shell (1) inserted between them when the can (3) moves closer to the sealing head (10) during the operation work steps in the sealing station of the sealing machine. - A first elastic device and a second elastic device, the first elastic device and the second elastic device being connected to corresponding first and second circular sealing sectors, so that when they come into contact with the proximal region (3i) of the can edge of the covering shell (1), they resist axial movement of the same circular sealing sector. - Heating device (12), the heating device is connected to the first circular sealing sector and the second circular sealing sector and is adapted to heat the first circular sealing sector and the second circular sealing sector to a specific and fixed sealing temperature; The sealing head is characterized by comprising a first elastic device and a second elastic device with different stiffnesses, respectively connected to a first circular sealing sector and a second circular sealing sector, wherein the first circular sealing sector and the first elastic device are configured to apply higher pressure on a first circumferential arc region of the can, and the second elastic device and the second circular sealing sector are configured to apply lower pressure on a second circumferential arc region of the can, to provide different adhesion forces of the cover shell on the first circumferential arc region and the second circumferential arc region having corresponding angular ductility, such that the cover shell can separate from the second circumferential arc region to open the can while remaining adhered to the first circumferential arc region.

2. The sealing head according to claim 1, wherein the first circumferential arc region and the second circumferential arc region are arranged at an angle such that the opening of the can faces the second circumferential arc region of the can.

3. The seal head of claim 1, wherein, The first elastic device includes a spring with greater stiffness when coupled to a first circular sealing sector located at a distal point (D) relative to the edge of the can adjacent to the can opening (3a); and the second elastic device includes a spring with lower stiffness when coupled to a second circular sealing sector located near a proximal point (P) relative to the edge of the can facing the can opening.

4. A seal head according to claim 3, characterised in that The sealing head includes a first elastic device with maximum stiffness when connected to a first circular sealing sector located near a distal point (D) relative to the edge of the can facing the can opening.

5. The sealing head according to claim 4, characterized in that, The first circular sealing sector is located near the farthest point of the can edge adjacent to the can opening.

6. The seal head of claim 1, wherein, The second elastic device has gradually decreasing stiffness when it is connected to the second circular sealing sector and is located near a point farther than the first circular sealing sector located near the far point (D) of the edge of the can facing the can opening.

7. A seal head according to any one of claims 2 to 6, characterised in that, The first circular sealing sector has a smaller circumferential extension than the second circular sealing sector.

8. The sealing head according to claim 7, wherein the circumferential extension gradually decreases.

9. A sealing machine including a sealing head (10) for applying a cover seal (1) to a can surface (3s) including a pull ring (3l) for discharging can contents, the sealing machine including a workstation wherein, in the operation step of applying the cover seal (1), the following items are axially aligned from bottom to top: - A pusher (4), which is provided with a support surface (6) for the can (3) to be sealed. -The container to be sealed (3). - Covering shell (1), the covering shell is connected to the suction cup device (8) to properly position it so as to cover the surface of the can to be sealed (3s). characterized in that The sealing machine includes a sealing head (10) according to any one of the preceding claims.

10. A can having a covering seal (1), characterized in that The can is produced in the workstation of the sealing machine according to claim 9.

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