Skin Packaging Machine

Abstract

A skin packaging machine in which a first continuous film and a second continuous and thermoplastic film above the first film are supplied in a forward direction of the machine. The machine includes a sealing station configured for receiving both films, and it comprises an upper tool pressing on the films to seal them to one another, with a closed holding contour delimiting the area of said films being sealed. The sealing station further comprises a sealing gasket attached to the holding contour, the sealing gasket having, on each side with respect to the forward direction, an operation zone with a notched configuration which is facing the space delimited by said sealing gasket.

Claims

1. A sealing station configured to receive a first film and a second film disposed above the first film, the sealing station having a rearward entrance side and a forward exit side and configured to seal the second film to the first film, the sealing station comprising: a lower tool that is configured to support the first film; and an upper tool positioned above the lower tool, in a first arrangement the upper and lower tools are in contact with one another, in a second arrangement the upper and lower tools are not in contact with one another, the upper tool including a heating surface and a gasket that is configured to urge the second film against the first film when the upper and lower tools are in the second arrangement, the gasket having a first side with a first operation zone, the first operation zone including notches that are separated by trenches, the notches facing inward into a space delimited by the gasket, the heating surface having a plurality of suction holes that are configured to draw the second film towards the heating surface when a suction is applied through the suction holes, the notches and trenches of the first operation zone being configured to cause the second film to be deformed inside the trenches in a tensed state to inhibit or reduce the formation of creases in the second film when the second film is drawn toward the heating surface.

2. The sealing station according to claim 1, wherein the notches of the first operation zone are configured to limit the deformation of the second film in the trenches in a manner that postpones a contact of the second film with the heating surface when the second film is drawn towards the heating surface.

3. The sealing station according to claim 1, wherein the gasket comprises a second side opposite the first side, the first and second sides of the gasket extending lengthwise in a direction transverse to the rearward entrance side and forward exit side of the sealing station, the second side the gasket having a second operation zone, the second operation zone including notches that are separated by trenches, the notches facing inward into the space delimited by the gasket, the notches and trenches of the second operation zone being configured to cause the second film to be deformed inside the trenches in a tensed state to inhibit the formation of creases in the second film when the second film is drawn toward the heating surface.

4. The sealing station according to claim 3, wherein the notches of the second operation zone are configured to limit the deformation of the second film in the trenches in a manner that postpones a contact of the second film with the heating surface when the second film is drawn towards the heating surface.

5. The sealing station according to claim 1, wherein the trenches of the first operation zone have a same first width and the notches of the first operation zone have a same second width, the second width being greater than the first width.

6. The sealing station according to claim 3, wherein the trenches of the first and second operation zones have a same first width and the notches of the first and second operation zones have a same second width, the second width being greater than the first width.

7. The sealing station according to claim 1, wherein the gasket has a first width outside the first operation zone, the notches of the first operation zone have a second width that is substantially the same as the first width.

8. The sealing station according to claim 3, wherein the gasket has a first width outside the first and second operation zones, the notches of the first and second operation zones have a second width that is substantially the same as the first width.

9. The sealing station according to claim 1, wherein the gasket has a thickness that is substantially uniform around an entire perimeter of the gasket.

10. The sealing station according to claim 1, wherein the trenches of the first operation zone have a same length and the notches of the first operation zone have a same second length.

11. The sealing station according to claim 3, wherein the trenches of the first and second operation zones have a same length and the notches of the first and second operation zones have a same second length.

11. The sealing station according to claim 1, wherein the first side of the gasket is disposed transverse to at least one of the rearward entrance side and forward exit side of the sealing station, the first side having a first length, the first operation zone extending less than the entire first length.

12. The sealing station according to claim 3, wherein the first and second sides of the gasket are each disposed transverse to at least one of the rearward entrance side and forward exit side of the sealing station, the first side having a first length, the first operation zone extending less than the entire first length, the second side having a second length, the first operation zone extending less than the entire second length.

13. The sealing station according to claim 1, wherein first operation zone is located nearer the rearward entrance side of the sealing station than to the forward exit side of the sealing station.

14. The sealing station according to claim 3, wherein the first and second sides of the gasket are arranged substantially parallel to one another with each of the first and second operation zones being located nearer the rearward entrance side of the sealing station than to the forward exit side of the sealing station.

15. A packaging machine comprising: a first feeding station for supplying a first film in a forward direction of the packaging machine; a second feeding station for supplying a second film in the forward direction and above the first film; and a sealing station that includes a lower tool and an upper tool, the lower tool being configured to support the first film, in a first arrangement the upper and lower tools are in contact with one another, in a second arrangement the upper and lower tools are not in contact with one another, the upper tool including a heating surface and a gasket that is configured to urge the second film against the first film when the upper and lower tools are in the second arrangement, the gasket having a side with an operation zone, the operation zone including notches that are separated by trenches, the notches facing inward into a space delimited by the gasket, the heating surface having a plurality of suction holes that are configured to draw the second film towards the heating surface when a suction is applied through the suction holes, the notches and trenches of the first operation zone being configured to cause the second film to be deformed inside the trenches in a tensed state to inhibit or reduce the formation of creases in the second film when the second film is drawn toward and heated by the heating surface.

16. The packaging machine according to claim 15, further comprising a pre-heating station located upstream from the sealing station in the forward direction for pre-heating the second film before being supplied to the sealing station, the sealing station having a rearward entrance side and a forward exit side, the operation zone being located nearer the rearward entrance side of the sealing station than to the forward exit side of the sealing station.

17. The packaging machine according to claim 15, wherein the first feeding station includes a cutting station upstream from the sealing station in the forward direction, the cutting station having a cutting tool that is suitable for generating at least one opening in the first film, the sealing station comprising vacuum means for applying a vacuum between the first and second films through the at least one opening during the sealing of the first and second films, the cutting tool being configured so that, or arranged in the packaging machine such that the at least one opening made in the first film coincides with a trench of the operation zone of the gasket during the sealing of the first and second films.

18. The packaging machine according to claim 17, wherein the cutting tool is configured for making an opening for each of the trenches of the operation zone of the gasket.

19. The packaging machine according to claim 17, wherein the sealing station comprises at least one additional element arranged in the lower tool that is configured for being introduced through the at least one opening made by the cutting tool in the first film.

20. The packaging machine according to any of claim 15, wherein the first feeding station comprises a feeder supplying the first film and a forming station downstream from the feeder in the forward direction, the forming station being configured for sequentially generate a plurality of cavities in the first film in the forward direction, the packaging machine comprising a separating station arranged downstream the sealing station in the forward direction and configured for cutting the first and second films to generate individual packages comprising a tray with a corresponding cavity and a flap around the cavity, the forming station being configured to form the cavity such that a width on the sides of the first film extending from a lateral end of the cavity to an end of the first film is left unformed, the sealing station being configured so that the gasket is supported on the first and second films beyond the flap, towards an outer side of the first and second films during the sealing of the first and second films.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a schematic view of a skin packaging machine according to one embodiment.

[0020] FIG. 2a is a partial section view of an upper tool and a lower tool of the sealing station of the machine of FIG. 1, tightly holding the films between them during sealing, in which the second film in the zone of a notch-free area of the sealing gasket is depicted by means of a continuous line, and the same second film in the zone of a notch of said sealing gasket is depicted by means of a discontinuous line.

[0021] FIG. 2b is a partial, perspective, section view of an upper tool and a lower tool of the sealing station of the machine of FIG. 1, tightly holding the films between them during sealing (the second film is not depicted).

[0022] FIG. 2c is a side section view of the tools of the sealing station of the machine of FIG. 1, tightly holding the films between them during sealing (the second film is not depicted).

[0023] FIG. 3 shows a sealing gasket of the sealing station of the machine of FIG. 1.

[0024] FIG. 4a shows a perspective view of a package generated in the machine of FIG. 1, in the form of a tray, with a packaged product.

[0025] FIG. 4b shows a side view of the tray of FIG. 4a, with the packaged product.

DETAILED DESCRIPTION

[0026] FIG. 1 shows a schematic view of a skin packaging machine 100 according to one embodiment. The machine 100 is suitable for packaging products P arranged between a first continuous film 10 and a second continuous film 20 sealed to one another around the perimeter of the product P arranged between both by means of heat, and these are then cut for generating individual packages with a product P packaged therein. In some of the drawings the products P are not depicted for the sake of clarity.

[0027] Continuous must be interpreted as the films 10 and 20 being supplied without pre-cuts, i.e., without having been previously cut to the sizes required for the final package. Therefore, the films 10 and 20 can be stored in the form of reels, for example, and can be gradually unwound from the corresponding reel to be supplied.

[0028] The machine 100 comprises a first feeding station 1 for supplying the first continuous film 10 in a forward direction A of the machine 100, a second feeding station 2 for supplying the second continuous film 20 in the forward direction A and above the first film 10, and a sealing station 3 which is configured for receiving both films 10 and 20 in said forward direction A, with the second film 20 above the first film 10, and for sealing them together using heat. Previously, particularly before the first film 10 is fed into the sealing station 3, the products P to be packaged are arranged on said first film 10 in a specific manner.

[0029] The skin packaging machines 100 works intermittently, one sealing operation being performed in the sealing station 3 every machine cycle. Once a cycle is performed and the films 10 and 20 are stationary, said films 10 and 20 are made to move in the forward direction A a specific distance to perform a new machine cycle. In every machine cycle, one product P is packaged in its corresponding package in the sealing station 3, or a plurality of products P can be packaged simultaneously (each one in a corresponding package). For this last case, the products P are arranged on the first film 10 before entering the sealing station 3, forming a line in the forward direction A (or a plurality of parallel lines), a plurality of products P being located in the sealing station 3 in one and the same machine cycle.

[0030] The sealing station 3 comprises an upper tool 3.1 depicted in FIGS. 2a, 2b and 2c, pressing on the films 10 and 20 and being supported on a lower tool 3.2 to apply said pressure, both films 10 and 20 being tightly held between both tools 3.1 and 3.2 during sealing. The upper tool 3.1 comprises at least: [0031] one closed holding contour 3.10 pressing on the films 10 and 20 during sealing, and delimiting the area of said films 10 and 20 to be sealed together in every cycle of the machine 100, [0032] one heating surface 3.4 delimited by the holding contour 3.10 and facing said area corresponding to the second film 20, [0033] heating means (not depicted in the drawings) for heating the heating surface 3.4, and [0034] suction means for bringing the second film 20 towards said heating surface 3.4 for heating, said heating surface 3.4 comprising a plurality of holes 3.41 that are part of the suction means and through which said second film 20 is brought towards said surface 3.4.

[0035] The suction means further comprise an actuator not depicted in the drawings, causing said suction through said holes 3.41. Suction means for this purpose in skin packaging machines 100 are already known, so neither their operation nor their configuration will be described in detail. Likewise, heating means are also known and can be, for example, resistances configured for heating said heating surface 3.4 when required.

[0036] The sealing station 3 further comprises a sealing gasket 3.12 which is attached to the holding contour 3.10 for preventing direct contact of the upper tool 3.1 and the films 10 and 20 during sealing, said films 10 and 20 therefore being protected from heat in the holding contour 3.10, and this is shown by way of example in FIG. 3. On the sides with respect to the forward direction A, the sealing gasket 3.12 comprises an operation zone 3.5 with a notched configuration which is facing the space delimited by said sealing gasket 3.12, such that when the second film 20 is brought towards the heating surface 3.4 for being heated, the second film 20 tends to tense up through the notch-free areas 3.51 of the operation zone 3.5 towards the heating surface 3.4, becoming deformed, whereas the notches 3.52 limit said deformation, thereby preventing early contact between said second film 20 and said heating surface 3.4, particularly in the zones of the notch-free area 3.51. The second film 20 tenses up and becomes deformed through said notch-free areas 3.51, and the notches 3.52 prevent early contact between said deformed part of the second film 20 and the heating surface 3.4 in the zone of the sealing station 3 that is arranged on the notch-free areas 3.51, thereby preventing the second film 20 from heating up too much in said zones prone to early contact, and due to its ductility caused by a higher temperature, causing damage to in the second film 20. According to some embodiments there are provided two operation zones 3.5. According to some implementations the operation zones 3.5 are the same and symmetrical with respect to the forward direction A.

[0037] The operation zone 3.5 therefore comprises a succession of notch-free areas 3.51 and of notches 3.52 distributed in the forward direction A. According to some embodiments the distribution of the notch-free areas 3.51 in the corresponding operation zone 3.5 and in the forward direction A is homogenous, the distribution of the notches 3.52 in said operation zone 3.5 and in the forward direction A therefore also being homogenous. According to some embodiments the length of all the notch-free areas 3.51 is the same in the forward direction A, and the length of the notches 3.52 is also the same in the forward direction A, although the length of one notch-free area 3.51 does not have to be the same length as one notch 3.52. The value of lengths can depend on different factors, such as the material, the properties or the thickness of the second film 20, for example.

[0038] The length of the notch-free areas 3.51 and the length of the notches 3.52 in the forward direction A are related to the deformation to be applied on the second film 20 and to the limitation of said deformation, respectively. The length of the notch-free areas 3.51 is long enough to cause said deformation and short enough to prevent early contact between said second film 20 and the heating surface 3.4. In turn, the length of the notches 3.52 is long enough to prevent early contact between said second film 20 and the heating surface 3.4 and short enough to allow deformation of the second film 20.

[0039] The width of the notch-free areas 3.51 and the width of the notches 3.52 in a direction transverse to the forward direction A are related to the deformation to be applied on the second film 20 and to the limitation of said deformation, respectively. The width of the notch-free areas 3.51 is big enough to cause said deformation and small enough to prevent early contact between said second film 20 and the heating surface 3.4. In turn, the width of the notches 3.52 is big enough to prevent early contact between said second film 20 and the heating surface 3.4 and small enough to allow deformation of the second film 20.

[0040] The thickness (height) of the sealing gasket 3.12 in the zones corresponding with the notch-free areas 3.51 and the thickness of said sealing gasket 3.12 in the zones corresponding with the notches 3.52 are related to the deformation to be applied on the second film 20 and to the limitation of said deformation, respectively. The thickness in the zones corresponding with the notch-free areas 3.51 is big enough to cause said deformation and small enough to prevent early contact between said second film 20 and the heating surface 3.4. In turn, the thickness of said sealing gasket 3.12 in the zones corresponding with the notches 3.52 is big enough to prevent early contact between said second film 20 and the heating surface 3.4 and small enough to allow the deformation of the second film 20. Preferably, the thickness of the sealing gasket 3.12 is homogenous (the same) around its entire perimeter.

[0041] Preferably, the length, width and thickness of the sealing gasket 3.12 in the zone corresponding with the notch-free areas 3.51 and the length, width and thickness of the sealing gasket in the zone corresponding with the notches 3.52 are related to the deformation to be applied on the second film 20 and to the limitation of said deformation, respectively, and said lengths, widths and thicknesses are related to one another to allow said deformation and to prevent said early contact between the second film 20 and the heating surface 3.4.

[0042] In some cases, the second film 20 can be exposed to a heating process before entering the sealing station 3, in which case the machine 100 comprises a pre-heating station (not depicted in the drawings) with heating means, such as a heating plate for example, arranged upstream from said sealing station 3 in the forward direction A. The need for heating the second film 20 in the sealing station 3 decreases as it starts from a higher temperature in said sealing station 3 compared to the case in which it is lacking said prior heating plate.

[0043] The films 10 and 20 are supplied in the forward direction A intermittently, such that in every machine cycle a first specific area of the second film 20 is exposed to the heat of the heating plate and a second area of said second film 20 is sealed to the first film 10 in the sealing station 3. In the following cycle, said first area is arranged in the sealing station, becoming a second area sealed to the first film 10. Due to the configuration of the heating plate and the supply direction of the second film 20 to the zone where it is heated by said heating plate, the end that is farthest downstream in the forward direction A of the second film 20 is no longer heated before entering the sealing station 3, such that it is shrink-wrapped and introduced in the sealing station 3 with a lower temperature than the rest of the second film 20. In the following cycle, in which said end will be the end that is farthest downstream in the forward direction A of the second film 20 being sealed to the first film 10 in the sealing station 3, said end is less hot and has a lower risk of adhering to the heating surface 3.4, and it also has a lower risk of creased being generated therein due to the shrink-wrapping process to which it was previously subjected. The higher the temperature of the second film 20, the more ductile it is, such that since said end is at a lower temperature, the rest of the second film 20 is more ductile and more easily and more quickly brought towards the heating surface 3.4, for which reason there is no risk of said end adhering to said heating surface 3.4 too soon.

[0044] For this reason, for these cases each operation zone 3.5 of the sealing gasket 3.12 can comprise a length that is smaller than the total length of said sealing gasket 3.12, each operation zone 3.5 extending in the forward direction A from the entrance into the sealing station 3 to a specific intermediate point. The operation zone 3.5 of the sealing gasket 3.12 therefore corresponds with the zone of the sealing station 3 where the second film 20 is provided with a higher initial temperature. As a result, the zone of the sealing gasket 3.12 associated with the less hot end of the area of the second film 20 to be sealed to the first film 10 in the sealing station 3 is not notched, but nevertheless since it is less hot, it does not present the risk of adhering to the heating surface 3.4 when not wanted, and since it was previously subjected to a shrink-wrapping process, the risk of generating creases in the package is eliminated.

[0045] In the embodiment of the machine 100 shown in the drawings, the first feeding station 1 comprises a cutting station 13 upstream from the sealing station 3 in the forward direction A, with at least one cutting tool which is suitable for generating at least one opening (not depicted in the drawings) in the first film 10, to later in the sealing station 3 generate a vacuum in the space existing between the area of the two films 10 and 20 delimited by the holding contour 3.10. If a plurality of products P is going to be simultaneously packaged in the sealing station 3, each one in its own package, this opening serves to generate a simultaneous vacuum in all the packages. Naturally, if instead of one opening more openings are made (both if only one product P is packaged and if a plurality of products P is simultaneously packaged), the vacuum is generated more quickly, and in some cases more efficiently. The sealing station 3 therefore receives the first film 10 with said opening and comprises vacuum means (not depicted in the drawings) for applying a vacuum between the two films 10 and 20 through said opening (in the mentioned space), during the sealing of said films 10 and 20, such that the product P arranged in said space is vacuum packaged.

[0046] The cutting tool is configured such that, or arranged such that in the machine 100 such that, the opening made on the first film 10 coincides with a notch-free area 3.51 of the operation zone 3.5 of the sealing gasket 3.12 of the sealing station 3 during the sealing of the two films 10 and 20. The aforementioned vacuum is thereby generated without having to make the opening at a point that will pertain to the final package and would therefore have to comply with a series of requirements (closed later) and would affect the appearance of the package. Furthermore, unlike what occurs in the prior art where to generate said vacuum without the necessary opening affecting the final package, said opening is made on the sides of the films 10 and 20 outside the holding contour 3.10; here, said films 10 and 20 do not required being acted on beyond said holding contour 3.10, and it is therefore not necessary to increase the width of said films 10 and 20 beyond said holding contour 3.10 for this purpose. This allows reducing the generated remnant 60 of the films 10 and 20, remnant 60 being understood as the material from said films 10 and 20 that is subsequently eliminated or disposed of, with the subsequent material and cost savings. Preferably, the remnant 60 is collected in a collecting station 6.

[0047] According to some embodiments the cutting tool is configured for making an opening for each of the notch-free areas 3.51 of the operation zone 3.5 of the sealing gasket 3.12 of the sealing station 3, although it is sometimes not necessary to make one opening for each of the notch-free areas 3.51.

[0048] In the embodiment of the machine 100 shown in the drawings, the final packages in which the products P are packaged can be trays 4 covered by a cover film. The trays 4 are generated from the first film 10, and the cover film is generated from the second film 20. Each tray 4 comprises a base 40 on which the product P is arranged, a flap 41 surrounding the base 40 at a different height and a wall 42 joining the flap 41 with the base 40, as depicted by way of example in FIGS. 4a and 4b, which show a final package (in the form of a tray) with a packaged product P. Therefore, in said embodiment the first feeding station 1 comprises a feeder 11 supplying the first continuous film 10 from a reel of film for example, and a forming station 12 downstream from the feeder 11 in the forward direction A. The forming station 12 is configured for generating a plurality of cavities 15 in the first film 10 in the forward direction A, as the first film 10 moves forward in said forward direction A, in one or more parallel lines, each cavity 15 being associated with a tray 4. The sealing station 3 is downstream from the forming station 12 in the forward direction A, such that said sealing station 3 receives said first film 10 already formed (with the cavities 15). The cutting tool is preferably upstream from the forming station 12 in the forward direction A, but it could also be downstream from the forming station 12, between said forming station 12 and the sealing station 3, in said forward direction A.

[0049] In the embodiment shown in the drawings, the machine 100 further comprises a separating station 5 arranged downstream from the sealing station 3 in the forward direction A, and configured for cutting the films 10 and 20 already sealed to one another and with the product P therein, thereby generating individual packages (each with its corresponding product P). The transverse and/or longitudinal cuts required for obtaining individual packages, depending on how the products P are packaged (in a single line in the forward direction A or in a plurality of parallel lines) are made in the separating station 5.

[0050] Each final package therefore comprises a tray 4 like the one discussed above (in the particular case that the final packages are of the tray type), with a cavity 15 and a flap 41 around said cavity 15. The forming station 12 is configured for forming a cavity 15 such that a width of the first film 10 extending from the lateral end of the first film 10 to the lateral end of said cavities 15 is left unformed, and the sealing station 3 is configured so that the sealing gasket 3.12 is supported on said non-formed zone for sealing the two films 10 and 20 to one another. Particularly, the sealing gasket 3.12 is supported on a part of said non-formed zone that is located more outwardly than the part that will later be the flap 41 of the corresponding tray 4. Acting on a zone of the films 10 and 20 that will later become part of an individual package, i.e., the flap 41, is avoided, which prevents marking said flap 41. In some cases, the zone that will become the flap 41 of a final tray 4 is also formed, so in these cases the sealing gasket 3.12 is supported on the non-formed zone. Therefore, in the embodiment shown in the drawings the configuration of the holding contour 3.10 and the configuration of the forming station 12 are related and comply with related parameters for the correct packaging of products P in said machine 100. Furthermore, the opening (or openings) made by the cutting tool is also located outside the flap of each tray 4, such that the vacuum of the package can be generated without the appearance of the tray 4 being affected as a result.

[0051] Additionally, the sealing station 3 can comprise additional elements not depicted in the drawings in the form of pins, for example, to assure the opening of the openings of the first film 10 while generating the vacuum between the first film 10 and the second film 20, and/or to tense up the second film 20 as it is brought towards the heating surface 3.4. Said additional elements are arranged in the lower tool 3.2 of the sealing station 3 below the notch-free areas 3.51 of the sealing gasket 3.12 of the upper tool 3.1, such that they are introduced through the openings of the first film 10 in the space of the notch-free areas 3.51 of the sealing gasket 3.12 and perform their function without generating a larger amount of remnant 60 of films 10 and 20.