IT201800008101A1 - MULTIPLE PLATES MOLD FOR HEAT-SEALING MACHINE - Google Patents

Description

Description of the invention entitled:

"MULTIPLE PLATES MOLD FOR HEAT SEALING MACHINE"

Description

Field of technique

The present invention operates in the field of packaging machines, in particular those suitable for sealing trays of any shape, with transparent film welded to the edge of the tray. Even more in detail, the present invention relates exclusively to the mold of any packaging machine.

Known art

The packaging sector is, nowadays, one of the most technologically advanced. Given the ever-increasing demand for packaged products of any type, in particular for food, for large-scale distribution in supermarkets, the machines that seal the containers must work at very high speed and with incredibly high efficiency.

Each failure leads to a machine downtime which could mean serious losses for the company in terms of logistics and turnover. Having to stop a machine to repair it, even for a short period of time, would mean the loss of hundreds of unsealed containers and many times the loss of the product (food) that cannot be recovered.

The molds are the component of the heat sealing machines that deals with the sealing of the transparent film on the edge of the container and the cutting of the portion of film just outside the sealed one.

The sealing takes place by heating the portion of the matrix that presses against the edge of the tray to be sealed, on which the transparent plastic film is superimposed.

After sealing, the film is usually cut by a blade that surrounds the edge of the tray. The critical issue currently unresolved in this processing phase concerns the point at which to cut the film. On the one hand, the customers' request is to cut the film as close as possible to the sealed edge, to avoid unsightly leftovers that could also escape from the lid of the package. On the other hand, it frequently happens that the blades that cut the film may meet the lower portion of the edge of the trays, ruining the package and wearing out much faster than expected. This happens all the more frequently the closer you get to the edge of the plastic tray. The greater wear of the blades is linked to the considerable hardness of the plastic of some types of containers.

At the level of industrial property rights, the sector is very crowded, both nationally and internationally. A large number of recent filings concern machines that seal containers, such as, for example, the patent extended with PCT procedure n. WO 2018069 880.

WO 2016 055 599, on the other hand, claims a specific heat sealing machine for packing frozen meat.

WO 2014 166 940 relates to a machine for packaging food in plastic containers in modified atmosphere which is configured to obtain the least possible scrap of the plastic film with which the sealing is carried out.

Although some machines on the market are able to carry out efficient packaging, they are not yet exempt from the critical issues described above.

The purpose of this patent is to propose a mold for any heat-sealing machine that solves all the aforementioned criticalities, combining the requests of the customers with the needs of the producers.

Description of the invention

According to the present invention, a mold is produced for any heat-sealing machine which effectively solves the above-mentioned problems. Advantageously, it can be installed in correspondence with existing machinery, regardless of their handling system (with slats or drag rods) and for any form of containers to be sealed, even if sealing in a modified atmosphere is required. advantageously including the mold described below in a sealed vacuum bell.

Unlike known molds, with the problems described above, the one of the present invention reverses the sequence of sealing and cutting into cutting and subsequent sealing with technical measures that prevent the cutting blade that cuts the plastic film from ever coming into contact with the plastic. containers and wear out prematurely, as well as avoiding the risk of cutting the edge of the container being processed, damaging it.

To obtain these results, advantageously, the mold is made from a plurality of superimposed plates.

Depending on the embodiments, said plates will be 4 or 5 in number and, more precisely, from top to bottom:

- a top plate;

- an internal plate;

- a film award plate;

- a contrast plate (if any);

- a bottom plate.

With the exception of the lower plate, all the others are advantageously connected to each other by a common system of secondary springs, preferably positioned at the four corners of the plates, which have the role of cushioning the contact between all these plates, protecting them from premature wear and adjusting their mutual end point.

The upper plate is substantially stationary and defines the "limit stop" of the closed configuration of the mold. The open or closed configuration of the mold is determined by the position of the bottom plate. When this is at the point of maximum lowering with respect to said upper plate which is fixed, the mold is in the open configuration. Said lower plate, rising, determines the progressive contact between all the intermediate plates and the assumption of the closed configuration of said mold.

During this lifting advantageously all the steps of blocking the film, cutting and sealing take place, to then free again the container by now sealed and allow it to move away from the mold.

Below the upper plate, therefore, an internal plate is connected through said system of springs, which is the one equipped with the cutting blade responsible for cutting the plastic film.

The configuration of said cutting blade is such as to surround the edge of the container, whatever its shape, exceeding its perimeter by a few millimeters or a zero distance, to allow a cut as close as possible to said edge or exactly in axis with it.

Underneath the internal plate, a film-pressing plate is connected, through a further register of secondary springs, which is located in a position immediately above said plastic film which passes through the mold. Advantageously, said film-pressing plate is located externally to a heated plate with a shape corresponding to the edge of the container and suitably configured to press the plastic film just cut against the edge of the container and, thanks to its heating, determine the sealing. Said heated sealing element can possibly be adjustable in its position in height so as to never cause the cutting elements to interfere with the container. In some versions, moreover, said heated sealing element can be mechanized to leave the cutting blade at a higher level than the heated sealing edge.

As already illustrated, below all the aforesaid plates there is the lower plate, which is responsible for moving the container to be sealed up and down.

In an alternative and preferable embodiment, between the upper plate and the film-pressing plate, there is a contrast plate which will be located below said plastic film which passes through the mold.

The function of this further component is to firmly hold the plastic film before it is cut by the cutting blade, resulting in a clear and precise separation. An incomplete cut of the film, in fact, could cause many problems, up to the jamming of the whole machinery if, for example, when the container is released, the film has not been completely disconnected from the container itself.

Advantageously, the sealing speed of the machines currently available on the market is very high, all the processing steps illustrated below take place in a single lifting and lowering of the lower plate:

(A) first step of presenting at least one container in correspondence with the mold which is in the open configuration (lower plate completely lowered);

(B) second lifting phase of the lower plate until it comes into contact with the film-pressing plate, also lifting said plastic film with respect to its original seat, stretching it. Advantageously, in case of presence of the contrast plate, during lifting, the lower plate will first contact said contrast plate which has the function of leveling itself on the plane of the edge of the container to be sealed and of acting as a lower support on which the plastic film undertakes to be cut, in a clear and precise way, in the following

(C) third phase of cutting the plastic film, which is performed automatically as a result of the further lifting of the lower plate until it reaches the cutting blade of the internal plate. Advantageously, the cutting blade is at a height such as to always be higher than the edge of the container. The cutting of the plastic film, therefore, always takes place far from the edge of the container, eliminating the risk of this being cut and that the blade wears prematurely. The cut follows the

(D) fourth phase of sealing the plastic film, advantageously performed automatically for the further lifting of the lower plate until the edge of the container reaches the heated edge of the film-pressing plate;

(E) fifth step of lowering said lower plate until reaching the open configuration again and starting a new welding cycle.

Even if the very short time interval between the cutting of the film and its sealing does not normally allow a significant displacement of the cut portion of the plastic film, technical measures can be envisaged that prevent unwanted displacements and therefore welds that differ from the standard required. These devices can be represented by common holding means, suitable for fixing the position of the cut portion of said plastic film before it is sealed, or a common suction pump able to start working after the cutting of the plastic film to hold it. last in the correct position to be sealed on the edge of said container.

The preferred embodiment of the present invention, which is also the most advantageous, also comprises at least one adjustment device connected below the upper plate and a system of main springs which protrude above the upper plate.

The adjustment device crosses the internal plate and protrudes from the bottom of the latter by a predetermined distance designed to determine the "limit stop" of the film-pressing plate at the desired height. Advantageously, said adjustment device, being "adjustable" by nature, allows an operator to adjust the width of the stroke of said film-pressing plate when the mold assumes said closed configuration. This means that the same mold can be easily and quickly adjusted to operate on a multiplicity of containers different in shape and size.

Finally, the main springs are connected at the top to the film-pressing plate, cross the internal plate and protrude above the top plate. They are advantageously adapted to regulate the pressure exerted by the lower plate against the film-pressing plate. The advantageous removal system to which they are connected allows their exclusive disassembly without having to act on the entire top plate or on other components of said mold.

The advantages offered by the present invention are evident in the light of the description set out up to now and will be even clearer thanks to the attached figures and the related detailed description.

Description of the figures

The invention will be described below in at least one preferred embodiment for explanatory and non-limiting purposes with the aid of the attached figures, in which:

- FIGURE 1 shows an overall three-dimensional view of the mold 100 of the present invention, in its preferred embodiment.

- FIGURE 2 illustrates the mold 100 in the open configuration, before the start of the work cycle, with the container 10 still open ready to be sealed by the plastic film 20.

- FIGURE 3 shows a first lifting of the lower plate 150 at the beginning of the work cycle until it comes into contact with the contrast plate 140.

- FIGURE 4 shows the contact with the film-pressing plate 130 and the consequent cutting of the plastic film 20.

- FIGURE 5 shows the previous Fig. 4 in detail to better appreciate the position of the cutting blade 125 which is always higher than the plane of the edge 11 of the container 10. From here you can also see the "limit switch" represented by the position of the device adjustment 160.

- FIGURE 6 illustrates the subsequent sealing phase in which the plastic film 20 is compressed between the edge 11 of the container 10 and the heated edge 170. - FIGURE 7, finally, represents the end of the work cycle in which the container 10 is now sealed it can be removed from the mold 100.

Detailed description of the invention

The present invention will now be illustrated purely by way of example but not limiting or binding, by resorting to the figures which illustrate some embodiments relating to the present inventive concept.

With reference to FIG. 1 shows a mold 100 according to the preferred embodiment of the present invention.

It is made up of five superimposed layers or plates and, like normal molds, it is suitable for sealing a plastic film 20 on the edge 11 of a common food container 10.

Already from this first image, in addition to the plates whose operation will be illustrated in detail later on, it is possible to notice the main springs 190 which protrude above the upper plate 110. Said springs 190 are connected above the plate of the removal system 200, crossing the upper plate 110 and internal plate 120. They cushion the impacts between the aforesaid plates, extending their useful life and making the welding cushioned. Their replacement is facilitated by the presence of the removal system 200 which allows the exclusive disassembly of the springs 190 without acting on the other components of the mold 100.

Again with reference to Fig. 1, the presence of an adjustment device 160 fixedly connected below said upper plate 110, able to cross said internal plate 120 and projecting below from the latter by a predetermined distance, is highlighted laterally. “End of stroke” of the film press plate 130 at the desired height. The possibility of adjusting the projection of the adjustment device 160 therefore allows you to adjust the width of the stroke of the film-pressing plate 130 adapting to the various shapes and sizes of the containers 10.

It can also be noted that among all the plates with the exception of the lower plate 150 there are registers of secondary springs 180 which avoid strong collisions between the plates due to the high speed of execution of a work cycle.

Turning now to a detailed explanation of these work phases, with the help of the attached figures, it is of interest to specify that although their illustration requires a few minutes of explanation, everything takes place at very high speeds permitted by all the technical devices aimed at amortize the contacts between the various constituent parts of the machinery object of this patent.

With reference to Fig. 2 there is shown a container 10 still without sealing which is presented in the mold 100 by the movement system of the machine which exploits the present invention (this container handling mechanism can be of any known type). The mold 100 is in the so-called open configuration.

The second lifting phase B is illustrated in Fig. 3: the lower plate 150, that is the one that houses the container 10, rising up, comes into contact with the contrast plate 140 which has the function of leveling itself on the plane of the edge 11 of said container 10, thus acting as a lower support surface on which said plastic film 20 engages to be first locked and then cut in a clear and precise manner in the third cutting step C. More specifically, during the third cutting step C (Fig. 4), the plastic film 20 is lifted from its seat and stretched between said contrast plate 140 and the internal plate 120 placed above. This positioning causes when the lower plate 150 is raised further, the plastic film 20, well stretched, encounters the cutting blade 125 which cuts it off neatly.

With reference to Fig. 5, the very important mutual configuration of the various parts that contribute to a cut of such precision is shown. It should be noted that, following the appropriate adjustments of the springs 180-190 and of the adjustment device 160, when the mold 100 is in the closed configuration, said cutting blade 125 is at a higher level than the edge 11 of said container 10 to be seal, avoiding the above problems.

The fourth step of sealing the plastic film 20 is illustrated in Fig. 6. It consists in a further lifting of the lower plate 150 until the edge 11 of the container 10 reaches the heated edge 170 of the film press plate 130. The temperature at the which the heated edge is found to make the portion of plastic film 20 which has just been cut adhere to the edge 11 of the container 10 in a stable manner and above all with millimeter precision.

Finally, the lowering of the lower plate 150 will result in a new achievement of the open configuration (Fig. 7) and the possibility of starting a new welding cycle starting from the activation of the handling system of the containers 10 to be welded.

Finally, it is clear that modifications, additions or variants that are obvious to a person skilled in the art can be made to the invention described up to now, such as for example the extrusion of the sealing element so as to make it protrude beyond the blade in the case of particular shapes of containers which do not allow correct operation with the configuration described in the images, without thereby departing from the scope of protection provided by the attached claims.

Claims (11)

Claims 1. Mold (100) with multiple plates for heat-sealing machine, suitable for sealing a plastic film (20) on the edge (11) of a plurality of containers (10), said mold (100) being capable of reversibly assuming a configuration open and a closed configuration respectively adapted to allow the transit of the handling system of the heat sealing machine to present the containers (10) inside the mold (100) itself and to perform the sealing operations of said containers (10) by means of said film plastic (20); said mold (100) being characterized in that when it is in the closed configuration, the cutting of said plastic film (20) is performed first and, subsequently, it is sealed at the edge (11) of the relative container (10); said mold (100) being constituted at least by: - a fixed upper plate (110), designed to define the "limit switch" of the closed configuration, to which a system of secondary springs (180) is connected at the bottom, a - movable internal plate (120), adapted to allow the adjustment of the pressure exerted on the other components of the mold (100) when this is in said closed configuration; said internal plate (120) being equipped with at least one cutting blade (125) suitable for cutting said plastic film (20), when said mold (100) is in the closed configuration, reproducing the shape of the edge (11) of the container ( 10) on which subsequently, said cut portion of said plastic film (20) will be sealed; said internal plate (120) being connected at the bottom, by means of a common system of secondary springs (180), to a - movable film pressing plate (130), placed in a position immediately above said plastic film (20) which passes through said mold (100); said film-pressing plate (130) being able to seal said plastic film (20) already cut, by means of a heated edge of a sealing element (170) able to press said plastic film (20) against the edge (11) of the container (10) to be sealed by determining its adhesion; - a lower plate (150) movable, designed to raise and lower reversibly to determine the assumption, respectively, of the closed configuration and the open configuration of said mold (100); said lower plate (150) being equipped with at least one cell suitably configured to engage with the upper portion of said container (10) to be sealed and moved inside said mold (100); said mold (100) operating according to the following steps: (A) first step of presenting at least one container (10) in correspondence with said mold (100) which is in the open configuration; (B) second lifting step of the lower plate (150) until it comes into contact with said film-pressing plate (130), also lifting said plastic film (20) with respect to its original seat, stretching it; (C) third step of cutting the plastic film (20) performed automatically for the further lifting of the lower plate (150) until it reaches said cutting blade (125) of said inner plate (120); (D) fourth phase of sealing the plastic film (20) performed automatically for the further lifting of the lower plate (150) until the edge (11) of the container (10) reaches the heated edge (170) of said film award plate (130); (E) fifth step of lowering said lower plate (150) until reaching the open configuration and beginning of a new welding cycle. 2. Multiple plate mold (100) for heat-sealing machine, according to the previous claim 1, characterized in that it comprises a contrast plate (140) placed below said plastic film (20) and said film-pressing plate (130) and above said lower plate (150); said contrast plate (140) being connected to said film pressing plate (130) by means of a common system of secondary springs (180) and being able, during the second lifting phase (B) of the lower plate (150), to contact said lower plate (150) and level on the plane of the edge (11) of said container (10), thus acting as a lower support surface on which said plastic film (20) is committed to be cut in a clear and precise manner in the third phase ( C) cutting. Multiple plate mold (100) for heat sealing machine, according to any one of the preceding claims 1 or 2, characterized in that when in said closed configuration, said cutting blade (125) of said inner plate (120) cuts off said film plastic (20) being at a higher level than the edge (11) of said container (10) to be sealed. 4. Multiple plate mold (100) for heat-sealing machine, according to any one of the preceding claims, characterized in that it is equipped with at least one adjustment device (160) connected below said upper plate (110), able to cross said plate internal (120) protruding from below by a predetermined distance suitable to determine the "end of stroke" of the film-pressing plate (130) at the desired height; said adjustment device (160) being able to allow an operator to adjust the stroke width of said film-pressing plate (130) when said mold (100) assumes said closed configuration. 5. Mold (100) with multiple plates for heat-sealing machine, according to any one of the preceding claims, characterized in that it is equipped with common holding means suitable for fixing the position of the cut portion of said plastic film (20) before it is sealed on the edge (11) of the corresponding container (10). 6. Mold (100) with multiple plates for heat-sealing machine, according to any one of the preceding claims, characterized in that said upper plate (110) is connected to a common suction pump able to come into operation after cutting the plastic film ( 20) to hold the latter in the correct position to be sealed on the edge (11) of said container (10). 7. Multiple plate mold (100) for heat-sealing machine, according to any one of the preceding claims, characterized in that it is equipped with a common rapid removal system (200) connected to main springs (190) adapted to regulate the pressure exerted from the lower plate (150) against said film-pressing plate (130); said main springs (190) being connected above said press-film plate (130), crossing said internal plate (120) and projecting above said upper plate (110); said removal system (200) being able to allow the exclusive disassembly of said main springs (190) avoiding the disassembly of the entire upper plate (110) or other components of said mold (100). 8. Multiple plate mold (100) for heat-sealing machine, according to any one of the preceding claims, characterized in that it is included in a watertight vacuum bell adapted to allow the sealing of said containers (10) in a modified atmosphere. Multiple plate mold (100) for heat sealing machine, according to any one of the preceding claims, characterized in that it is suitable for sealing containers (10) of any shape and size. 10. Multiple plate mold (100) for heat-sealing machine, according to any one of the preceding claims, characterized by the fact that it can be applied to heat-sealing machines of any type, both equipped with a slat advancement system and equipped with a rod advancement system . 11. Multiple plate mold (100) for heat-sealing machine, according to any one of the preceding claims, characterized in that said heated edge (170) of said film-pressing plate (130) is adjustable in height and, during said fourth step of sealing (D), said heated edge (170) is able to lower to a predetermined height until it comes into contact with the edge (11) of the container (10) to seal the plastic film (20) which has just been cut.