VERTICAL PACKAGING MACHINE

Abstract

The invention relates to a vertical packaging machine comprising a forming tube, an internal passage section, and retaining means associated with the forming tube. The retaining means comprise a retaining device (3) configured to move between a blocking position (P1) in which it at least partially blocks the internal passage section of the forming tube, and a release position (P2) in which it does not block said internal passage section of the forming tube. In the blocking position (P1), the retaining device (3) is positioned at a fixed height and is configured to prevent the passage of a product through said internal passage section of the forming tube. Upon moving to the release position (P2), said retaining device (3) is removed from the path taken by said product.

Description

VERTICAL PACKAGING MACHINE TECHNICAL SECTOR The present invention relates to vertical packaging machines. PRIOR STATE OF THE ART A vertical packaging machine comprises a hollow forming tube with an inlet and an outlet downstream of the inlet. The forming tube is configured to receive a continuous sheet from a sheet feeder and to shape the sheet into a tube. The machine includes a longitudinal sealing tool for longitudinally sealing the tubular sheet, thus creating a sheet tube. The machine further comprises a sealing and cross-cutting tool located downstream of the forming tube. This tool cuts the sheet metal tube and seals it on both sides of the cut, creating a sheet metal tube closed at one end upstream of the cut and a closed container downstream of the cut. The product to be packaged is fed into the forming tube through its inlet and exits through the outlet, ultimately being deposited onto the sealing and cross-cutting tool or onto the closed end of the sheet metal tube. The machine includes a drive mechanism to advance the sheet metal tube, such that when the sealing and cross-cutting tool operates, a portion of the sheet metal tube containing a product is located downstream of both the forming tube and the sealing and cross-cutting tool. Thus, after the sealing and cross-cutting tool has operated, the product is packaged in a container that is physically separated from the sheet metal tube. During its descent along the tube, the product increases its speed due to gravity. This can mean, especially with longer forming tubes, that the product strikes the sealing and cutting tool and breaks or is damaged by the force of the impact, or that the product tears or breaks the foil tube, for example, by impacting the closed-end seal or the tube walls, thus compromising the integrity of the packaging. To solve this problem, the forming tube can be tilted with respect to the vertical, thus decreasing its falling speed. US4722373A also discloses a machine that solves this problem. This machine has multiple platforms distributed inside the forming tube at different heights, which move vertically together towards the outlet. Inside the forming tube, a vertical wall divides it longitudinally into two zones. The first zone is where the product to be packaged is fed and where the platforms move downwards, while the second zone is not. RCbi nn / C7n7 / e / YiAi feeds the product and through which the platforms fold back upwards. Each product to be packaged that is fed into the forming tube is supported on a platform and descends through this first section of the forming tube accompanied by the corresponding platform. Thus, the product no longer accelerates during its descent through the forming tube due to gravity, and only experiences acceleration between the outlet of the forming tube, where the platform ceases to support it, and the sealing and cross-cutting tool or the sealed end of the sheet tube. This eliminates or reduces the risk of striking the product or negatively affecting the integrity of the package. This allows for multiple products to be placed inside the forming tube simultaneously, as many as there are platforms present at the same time. EXPLANATION OF THE INVENTION The object of the invention is to provide a vertical packaging machine, as defined in the claims. The vertical packaging machine comprises a vertical forming tube with a product inlet, a product outlet downstream of the inlet, and an internal passage section. The machine further comprises retaining means associated with the forming tube, comprising at least one retaining device configured to move between a locked position, in which it at least partially blocks the inner passage section of the forming tube between the inlet and outlet, and a released position in which it does not block said inner passage section of the forming tube. In the context of the invention, “not blocking” is to be interpreted as not preventing the passage of the product through the interior of the forming tube (through the corresponding passage section), and “at least partially blocking” is to be interpreted as preventing the passage of the product through the interior of the forming tube (through the corresponding passage section). The retaining device is arranged at a fixed height relative to the outlet of the forming tube in the locked position, and configured to, in the locked position, prevent the passage of a product through said inner passage section of the forming tube and, when moving from the locked position to the released position, to move out of the way of the product through said inner passage section of the forming tube. In this way, the product is easily allowed to descend gradually along the forming tube by gravity, without any assistance. When the product exits the forming tube through the outlet, it does not do so at a speed that could damage it by hitting the sealing and cross-cutting tool, or that could negatively affect the integrity of the container by impacting the walls or the seals of the foil tube. Furthermore, by preventing the retention device from moving vertically inside the forming tube in the locked position, it also prevents the... RCbl nn / C7n7 / R / VIAI retention device has to return through the inside of the forming tube to its initial starting point, in a simple way it is possible to take advantage of a larger internal passage section of the forming tube, allowing feeding a greater quantity of product, as well as optimizing the consumption of film to generate the containers. These and other advantages and features of the invention will become evident from the figures and the detailed description of the invention. DESCRIPTION OF THE DRAWINGS Figure 1 shows a first embodiment of the vertical packaging machine. Figure 2 shows in perspective some retaining means of the machine of Figure 1, attached to a retaining structure of said machine. Figure 3a shows the retaining means of Figure 2 from the side. Figure 3b shows the retaining means of Figure 2 from the side, with the retaining devices in a different position compared to the position they are in in Figure 3a. Figure 4a shows a lateral view of retention means of another embodiment of the machine of the invention, comprising a plurality of retention devices that are arranged in an intermediate position between the locking position and the release position, which move simultaneously and are attached to a retention structure of said machine. Figure 4b shows a side view of retention means of another embodiment of the machine of the invention, comprising a plurality of retention devices that are arranged in an intermediate position between the locking position and the release position, which move simultaneously and are attached to a retention structure of said machine. Figure 5 shows in perspective some retention means of another embodiment of the machine of the invention, comprising a single movable band and attached to a retention structure of said machine. Figure 6 shows a lateral view of retention means of another embodiment of the machine of the invention, comprising two retention assemblies associated by two movable bands and attached to a retention structure of said machine. RCbl nn / C7n7 / R / YIAI Figure 7 shows a lateral view of retention means of another embodiment of the machine of the invention, comprising two retention assemblies associated with drive means of the machine and attached to a retention structure of said machine. Figure 8 shows a lateral view of retention means of another embodiment of the machine of the invention, comprising two movable belts with respective active drive means for each movable belt and which are attached to a retention structure of said machine. DETAILED EXPLANATION OF THE INVENTION The vertical packaging machine 100, as shown in Figure 1, comprises a hollow vertical forming tube 1 into which the products to be packaged are introduced. The forming tube 1 comprises an inlet opening 11 through which the products to be packaged enter the forming tube 1, an outlet opening 12 downstream of the inlet opening 11 through which the products exit the forming tube 1, and an internal passage section longitudinally delimited between the inlet opening 11 and the outlet opening 12 through which the products to be packaged fall. Preferably, the internal passage section remains constant along the entire length of the forming tube 1. Preferably, the forming tube 1 comprises at least two opposing and parallel vertical walls. Preferably, the forming tube 1 is rectangular, such that the internal passage section is rectangular and is bounded by four internal vertical walls of the forming tube 1. When the forming tube 1 is rectangular, a first vertical wall of the forming tube 1 faces a third vertical wall of the forming tube 1, and a second vertical wall of the forming tube 1 faces a fourth vertical wall of the forming tube 1, each vertical wall preferably being at 90° to the adjacent vertical wall. Machine 100 also includes: • a sheet feeder 2 to feed the forming tube a continuous sheet not shown in the figures, the forming tube 1 being configured to give a tubular shape to said sheet; • a longitudinal sealing tool 6 configured to longitudinally seal together the longitudinal ends of the tubular-shaped sheet surrounding the forming tube 1, generating a sheet tube not shown in the figures; and • a transverse sealing and cutting tool 5 arranged downstream of the forming tube 1 and configured to seal and transversely cut the sheet tube, obtaining a closed sheet tube upstream of the transverse cut and a closed container (not shown in the figures) physically separated from the sheet tube downstream of said transverse cut, with the corresponding product remaining packaged in the container. RCbl nn / C7n7 / R / YIAI Preferably, the machine 100 comprises a hopper 10 arranged upstream of the forming tube 1 and connected to the inlet 11 of said forming tube 1, such that the product falls through the hopper 10, enters the forming tube 1 through the inlet 11, and exits said forming tube 1 through the outlet 12. Depending on when the transverse sealing and cutting tool 5 acts on the sheet tube to perform the sealing and cutting, and on when and at what speed the product reaches the outlet 12 of the forming tube 1, the product may fall against the transverse sealing and cutting tool 5 if it is acting, or onto the closed end of the sheet tube if the transverse sealing and cutting tool 5 is not acting on the sheet tube.Depending on the situation, the product may be damaged or broken due to impact with the transverse sealing and cutting tool 5, or the integrity of the packaging may be compromised, for example, by causing the sealed end of the foil tube to break. This problem becomes more significant the longer the forming tube 1 is. To solve this problem, the machine 100 further comprises retaining means associated with the forming tube 1 and comprising at least one retaining device 3, which enables the product to descend through the forming tube 1 in a stepped manner. In some embodiments, the retaining means are attached to the forming tube 1, thus being directly associated with it, while in other embodiments, the machine 100 comprises a retaining structure 101 housed inside and fixed to the forming tube 1, and the retaining means are attached to said retaining structure 101 so as to be associated with the forming tube 1 via said retaining structure 101. The retaining structure 101 is preferably hollow, with the retaining means housed within said retaining structure 101 (at least partially), and may comprise a closed or open perimeter.For example, in the case of a rectangular forming tube 1, the retaining structure 101 may also be rectangular (closed perimeter) or may comprise three vertical walls in the shape of a “U” or other similar shape (open perimeter), but preferably, whether open or closed perimeter, it follows the shape of the forming tube 1 (except in the open part, in the case of an open perimeter). The retention means may comprise a number of retention devices 3 that preferably depends on the length of the forming tube 1 and / or the characteristics of the product P to be packaged, so there may be machines 100 with a single retention device 3 and machines 100 with a plurality of retention devices 3. In cases where the machine 100 comprises a plurality of retention devices 3, said retention devices 3 are distributed longitudinally along the length of the forming tube 1. Figure 2 shows, as an example, the retaining means of a first embodiment of a machine 100 comprising a plurality of retaining devices 3, said retaining means being attached to a retaining structure 101 (with an open perimeter in this case) of said machine 100. The vertical walls of the retaining structure 101 can be made of a transparent material as in Figure 2 (for example, methacrylate), although they could be opaque materials. RCbl nn / C7n7 / R / VIAI The retention device 3 prevents the speed of the product falling inside the forming tube 1 from increasing uncontrollably from the inlet 11 to the outlet 12, due to gravity, so that the product reaches the end of the sheet tube or hits the transverse sealing and cutting tool 5 at a lower speed compared to a machine without any retention device like the one proposed, avoiding damage or breakage of the product or compromising the integrity of the container for this reason (or at least greatly reducing the risk of this problem). In all embodiments of machine 100, each retaining device 3 is configured to be in a locking position P1 and a release position P2 (see, for example, Figures 3a and 3b), and to move between these positions P1 and P2. During the change of position of a retaining device 3, at least one element is displaced or moved, as will become evident throughout the description, and in the context of the invention, any element that moves during the change of position of a retaining device 3 is thus interpreted as a movable element. The machine 100 restraint means further comprise actuating means for causing said changes of position of the restraint device 3, and said actuating means may comprise active means 37.1 for causing all the changes of position, or active means 37.1 for causing the change of position in one direction (for example, from the release position P2 to the locking position P1 of a restraint device 3) and passive means 37.2 for causing the change of position in the opposite direction (in this example, from the locking position P1 to the release position P2 of said restraint device 3). The passive means 37.2 do not require a signal or control to actuate, and may comprise, for example, at least one spring, a pulley, or a counterweight. The active means 37.1, on the other hand, require a signal or control to actuate and may comprise, for example, at least one actuator in the form of a controllable motor or cylinder.Depending on the embodiment of machine 100, the active means 37.1 may comprise a plurality of actuators, in which case the actuation of said actuators would preferably be synchronized and / or coordinated. The actuating means are configured to act on at least one of the moving elements. All the moving elements of a restraining device 3 are linked together, such that acting on one of them may be sufficient to cause the change of position required for said restraining device 3 (such actuation may cause the movement of all the moving elements). Depending on the embodiment of machine 100, as will be detailed throughout the description, different retaining devices 3 are associated with each other, and it may be sufficient to act on one of the moving elements of these retaining devices 3 to cause the displacement of all of them. When there are retaining devices 3 not associated with each other, it is possible to require at least two active means 37.1 from the actuating means: one to cause the displacement of a first retaining device 3 and all the retaining devices 3 associated with that first retaining device 3, and another to cause the displacement of RCbl nn / C7n7 / R / YIAI a second retention device 3 (not associated with the first retention device 3) and all retention devices 3 associated with said second retention device 3. Machine 100 comprises a control unit 4 for controlling the position changes of the holding device 3. This control unit 4 may be a unit specifically designed for this function, or it may be the general control unit of Machine 100 or another control unit with additional functions. In particular, the control unit 4 communicates with the active means 37.1 of the drive means and is configured to control the actuation of these active means 37.1 with respect to the corresponding moving element(s). A control unit 4 may be, for example, a microcontroller, a microprocessor, an FPGA, or any other type of device with computing and / or control capabilities. Preferably, the change in position of the retaining devices 3 and the product feeding are coordinated to improve the efficiency and productivity of machine 100. Normally, the product is supplied to the forming tube 1 from a product dispenser (not shown in the figures) located upstream of the forming tube 1 and the hopper 10. In some embodiments, depending on the requirements or even the type of product dispenser used, for example, to detect when product is fed into the forming tube 1, machine 100 includes at least one sensor that detects the passage of the product. In other embodiments, such as those comprising a multi-head product dispenser, it is possible to know when the product is fed into the forming tube 1 by monitoring when the multi-head opens. In the P1 locking position, the retaining device 3 is at a fixed predetermined height with respect to the outlet 12 of the forming tube 1, between the inlet 11 and said outlet 12 of said forming tube 1, and at least partially blocks the passage section of the forming tube 1 at said fixed predetermined height, preventing the passage of a product from said fixed predetermined height towards the outlet 12. In the release position P2, the retaining device 3 does not block the passage section of the forming tube 1, so that when said retaining device 3 moves from the blocking position P1 to the release position P2, the product P whose fall had been interrupted by said retaining device 3 at the fixed predetermined height restarts its fall through the forming tube 1 towards the outlet mouth 12 from said fixed predetermined height, since said retaining device 3 no longer prevents its fall when in the release position P2. When the retaining device 3 moves to the release position P2, it is removed from the path of the product inside the forming tube 1, so that, in addition to releasing the product, it does not accompany the product as it falls towards the outlet 12 of the forming tube 1. The retaining device 3 thus does not move in a vertical linear direction along the forming tube 1, which RCbl nn / C7n7 / R / YIAI allows said retention device 3 not to interfere with the fall of the product or accompany it during its descent along the forming tube 1, thus increasing the productivity of the machine 100 with respect to the state of the art, as said product falls freely once the retention device 3 has moved to the release position P2 by taking advantage of the acceleration of gravity. When machine 100 comprises a plurality of retaining devices 3, each retaining device 3 is at a fixed predetermined height with respect to the outlet 12 of said forming tube 1 in its respective locked position P1, and these fixed predetermined heights are different from each other. Thus, a product fed into the forming tube 1 stops its fall down said forming tube 1 upon reaching the fixed predetermined height of a retaining device 3 in the locked position P1, and remains retained at that fixed predetermined height until said retaining device 3 moves to the release position P2, whereupon it resumes its fall towards the outlet 12 of the forming tube 1, until it reaches the fixed predetermined height of another retaining device 3 in the locked position P1, where it is again retained until said retaining device 3 moves to the release position P2, and so on.such that the maximum speed that said product can reach when leaving the forming tube 1 depends on the fixed height of the last retaining device 3 that has retained said product, the distance between said retaining device 3 and the outlet 12 being less than the distance between the inlet 11 and said outlet 12, thus making said speed lower compared to the case in which there is no retaining device 3 at all. Preferably, all the retention devices 3 are arranged at the same vertical distance from each other, so that the product travels the same height each time it falls from one retention device 3 to the next. This ensures that the product receives the same impact between one step and the next (between one retention device 3 and the next), increases the packaging rate of the machine 100 when more than one product is simultaneously placed inside the forming tube 1 at different heights (see example in figures 3a and 3b), and simplifies the synchronization of the product dispenser, the retention means, and the sealing and transverse cutting tool 5, among others, because all products take the same amount of time to fall from one step to the next (from one retention device 3 to the next). Figures 3a and 3b illustrate an example of the operation of the retaining means of an embodiment of machine 100. The retaining means shown in these figures comprise four retaining devices 3, two of which are in the locking position P1 and the other two in the release position P2. Figure 3a shows two products 91 and 92, each resting on a retaining device 3 in the locking position P1. Below each of these retaining devices 3 is another retaining device 3 in the release position P2. When the retaining devices 3 change position (the result shown in Figure 3b), each product 91 and 92 falls until it comes to rest on the next retaining device 3 in the locking position P1. RCbl nn / C7n7 / R / YIAI In this way, products 91 and 92 only accelerate until they encounter another restraint device 3 in the locking position P1, falling a distance equal to the distance between two adjacent restraint devices 3 before coming to a stop or braking again, thus preventing them from reaching higher speeds. At least in the examples in Figures 3a and 3b, the retaining structure 101 comprises a length equal to the length of the forming tube, so that the height H from a lower base of said retaining structure 101 to a retaining device 3 when said retaining device 3 is in the locking position P1 is equal to the corresponding fixed determined height with respect to the outlet mouth 12 of the forming tube 1. In embodiments of machine 100 in which the retaining means comprise a plurality of retaining devices 3, said retaining means may be configured so that when a first retaining device 3 is in the locking position P1, another retaining device 3 adjacent to said first retaining device 3 is in the release position P2 (see example of figures 3a and 3b), so that said retaining devices 3 are alternately in the locking position P1 and in the release position P2 along the length of the forming tube 1; or said retaining means may be configured so that all the retaining devices 3 are in the same position simultaneously, all the retaining devices 3 being at the same time in the locking position P1 or in the release position P2 (see figures 4a and 4b for example).In the latter case, the time it takes for the retaining devices 3 to move from the locking position P1 to the release position P2 and back to the locking position P1 is preferably less than the time it takes for the corresponding product to fall from one retaining device 3 to the next. Figures 4a and 4b show two embodiments where all the retaining devices 3 move simultaneously and in the same direction. In the embodiment of Figure 4a, the retaining means comprise a connecting bar 36 (or connecting element) that joins all the retaining devices 3 together, and the actuating means comprise active means (not shown) for moving the connecting bar 36 and passive means 37.2 (counterweights in this case) for moving the movable belt 31 and assisting the movement of the retaining devices 3.In the embodiment of figure 4b, the drive means comprise active means 37.1 for moving the movable band 31 and passive means 37.2 associated with each retention device (a spring in this case). When retaining means comprise a plurality of retaining devices 3, in some embodiments of machine 100, as shown in Figure 5, at least one retaining device 3 moves in a first direction D1 inside the forming tube 1 to reach the locking position P1 and in a second direction D2 opposite to the first direction D1 to reach the release position P2, and at least one retaining device 3 moves in the second direction D2 inside the forming tube 1 to reach the locking position P1 and in the first direction D1 to reach the release position P2, preferably in a synchronized manner. In Figure 5, all the retaining devices 3 are in an intermediate position between the locking position P1 and the release position P2. RCbi nn / C7n7 / e / YiAi release P2 to facilitate understanding. In other embodiments, such as the embodiment shown in the examples in Figures 4a and 4b, for example, all the retaining devices 3 move in the same direction to move to the locking position P1 and in the same direction to move to the release position P2. If machine 100 comprises inactive retaining devices 3 (which for whatever reason are not operational during the operation of machine 100), these retaining devices 3 remain in the release position P2 at all times, so as not to interfere with the product's descent. The explanations given above apply only to active retaining devices 3 (retaining devices 3 that are operational and change position during the operation of machine 100). In some embodiments of machine 100, the retaining means comprise a drive element 32 associated with each retaining device 3, and said drive element 32 is movable inside the forming tube 1 when the associated retaining device 3 changes position. In the case where machine 100 comprises a connecting bar 36, preferably said connecting bar 36 joins the corresponding retaining devices 3 via the drive elements 32.The retention means further comprise at least one movable belt 31 (for example, a conveyor belt), and said movable belt 31 and the drive element 32 move together, such that a section of said movable belt 31 associated with a drive element 32 is extended inside the forming tube 1 when the corresponding retention device 3 is in the locking position P1, blocking said section of the movable belt 31 at least partially the inner passage section of the forming tube 1 and said section acting as a retention device 3. Preferably, in these cases the forming tube 1 comprises at least two opposing vertical walls as mentioned above, and the drive element 32 is configured to move between both walls.Preferably, the retention means comprise a diverter 35 upstream of the drive element 32 and another diverter 35 downstream of said drive element 32 associated with each retention device 3, to guide the displacement of the moving belt 31. Preferably, a drive element 32 comprises a roller, a stem or a similar element. The section of the moving belt 31 associated with the drive element 32 may be arranged outside or inside the forming tube 1, or inside the retaining structure 101 in embodiments of the machine 100 comprising a retaining structure 101, with the corresponding retaining device 3 in the release position P2. In embodiments comprising said section of moving belt 31 arranged outside the retaining element 101 or outside the forming tube 1, the deflectors 35 may correspond, for example, to a through-hole made in the retaining structure 101 and / or in the forming tube 1, as appropriate, for inserting the moving belt 31 inwards. In other embodiments in which the section of moving belt 31 is arranged inside the forming tube 1 or inside the structure 101, the deflectors 35 may correspond, for example, to a roller, a rod, or the like arranged inside the forming tube 1. RCbl nn / C7n7 / R / VIAI In the simplest embodiments of machine 100 comprising such restraining means, said machine 100s comprise a single restraining device 3, a single drive element 32, and a single movable belt 31. However, in other, less simple embodiments, the machine 100s comprise a plurality of restraining devices 3, a drive element 32 associated with each restraining device 3, and one or more movable belts 31. For example, in the embodiment of Figures 3a and 3b, the restraining means comprise a single movable belt 31 associated with all the drive elements 32, whereas in the embodiment shown in Figure 6, the drive means comprise two movable belts 31 (this embodiment is otherwise similar to that of Figures 3a and 3b). In some embodiments of machine 100, such as in the first embodiment and in the embodiment of Figure 6, for example, the retention means comprise at least one retention assembly 200 with a first retention device 3 and a second retention device 3 distributed longitudinally along the length of the forming tube 1, the first retention device 3 being the retention device furthest from the outlet 12 of the forming tube 1 and the second retention device 3 being the retention device closest to the outlet 12 of the forming tube 1. The retention assembly 200 comprises a connecting unit 33 for joining together the two drive elements 32 associated with the two retention devices 3 of said retention assembly, and said connecting unit 33 comprises a pivot axis 330 fixed with respect to the forming tube 1 and a connecting bar 331 joining both drive elements 32.The pivot axis 330 is directly connected to the forming tube 1, or to the retaining structure 101 in embodiments of the machine 100 comprising a retaining structure 101. The connecting unit 33 may comprise two parallel connecting bars 331, as shown in Figure 2. Each of the connecting bars 331 is connected to the two drive elements 32 of said retaining assembly 200 and is arranged facing each other on either side of said drive elements 32. Each pivot axis 330 is connected to both connecting bars 331. The connecting bars 331, and therefore the drive elements 32, rotate about the pivot axis 330 when a change of position of the retaining devices 3 of the retaining assembly 200 is caused, such that both retaining devices 3 of the same retaining assembly 200 change position simultaneously with a single actuation.Therefore, in a 200 retention assembly, when the first retention device 3 is in the locking position P1, the second retention device 3 is in the release position P2 and vice versa. In some embodiments of machine 100, such as the first embodiment and the embodiment of Figure 6, for example, the retaining means comprise a plurality of retaining assemblies 200 as described above, and these retaining assemblies 200 are distributed along the length of the forming tube 1, one after the other. In some of these embodiments, such as the first embodiment, for example, the retaining means comprise a single movable band 31 that is associated with all the retaining assemblies 200 (and therefore with all the retaining devices 3 of the retaining means). RCbl nn / C7n7 / R / VIAI In other embodiments of machine 100 in which the retaining means comprise a plurality of retaining assemblies 200, as for example in the one shown in Figure 6 where two retaining assemblies 200 are depicted, said retaining means comprise a number of movable bands 31.1 and 31.2 equal to the number of retaining assemblies 200 (two in this case). One movable band 31.1 is associated with the first retaining device 3 of the retaining assembly 200 furthest from the outlet 12 of the forming tube 1 and with the second retaining device 3 of the retaining assembly 200 closest to said outlet 12, and each of the remaining movable bands 31.2 is associated with the second retaining device 3 of a retaining assembly 200 and with the first retaining device 3 of the retaining assembly 200 that is arranged adjacent to and downstream of said retaining assembly 200. In other embodiments of machine 100, such as the one shown in Figure 7 where two retaining assemblies 200 are depicted, the retaining means comprise a plurality of retaining assemblies 200 distributed along the length of the forming tube 1 one after the other and a number of movable bands 31.1 and 31.2 equal to the number of retaining assemblies 200 (two in this case). Each movable band 31.1 and 31.2 is associated with the first and second retaining device 3 of the same retaining assembly 200. In these embodiments, preferably, as in the embodiment of Figure 7, the drive means are associated with all the retaining assemblies 200, such that all the retaining devices 3 move simultaneously. In some embodiments of machine 100 in which the restraint means comprise a plurality of restraint devices 3, a drive element 32 for each restraint device 3 and at least one movable band 31, at least one drive element 32 moves in a first direction D1 when the corresponding restraint device 3 moves to the locking position P1 and in a second direction D2 opposite to the first direction D1 when said corresponding restraint device 3 moves to the release position P2, and at least one drive element 32 moves in the second direction D2 when the corresponding restraint device 3 moves to the locking position P1 and in the first direction D1 when the corresponding restraint device 3 moves to the release position P2.Retaining devices 3 whose driving elements 32 move in the first direction D1 to reach the locking position P1 can form a first retaining group, and retaining devices 3 whose driving elements 32 move in the second direction D2 to reach the locking position P1 can form a second retaining group, the retaining means thus comprising two retaining groups. The retaining devices 3 of the first retaining group are configured to be in the locking position P1 when the retaining devices 3 of the second retaining group are in the release position P2, and the retaining devices 3 of the first retaining group are configured to be in the release position P2 when the retaining devices 3 of the second retaining group are in the locking position P1.A single movable band 31 may be associated with all the drive elements 32 (see Figure 5), or the retention means may comprise a first band 31.1 associated with all the drive elements 32 of the first retention group and a second movable band 31.2 associated with all the drive elements 32 of the second retention group (see Figure 8). In the case of the embodiment represented in the. RCbl nn / C7n7 / R / VIAI figure 8, the drive means comprise respective active means 37.1 for each moving band 31.1 and 31.2. Some embodiments of machine 100 comprising a plurality of retaining devices 3 with associated drag elements 32 and at least one movable belt 31, to facilitate the simultaneous movement of all the retaining devices 3, the retaining means may further comprise a joining element 36 to join all the drag elements 32 together, as in the embodiments shown in some figures. In any embodiment of machine 100 in which the retaining means comprise at least one drive element 32, said retaining means may comprise guiding means 38 for guiding the displacement of the drive element 32 (see Figures 4a, 4b, and 5, for example). For example, the forming tube 1, or the retaining structure 101 in embodiments of machine 100 comprising a retaining structure 101, may comprise a groove (which may be through-groove) with the shape of the desired displacement (linear or curved, for example), and one end of the drive element 32 (or an additional element attached to said end of the drive element 32) is housed in the groove. Preferably, the guiding means comprise two grooves, one groove associated with each end of the drive element 32.Alternatively, the forming tube 1, or the retaining structure 101 in embodiments of machine 100 comprising a retaining structure 101, may comprise a complementary projection or guide (not shown in the figures) and the drive element 32 may comprise a groove cooperating with the guide or projection of the forming tube 1 or the retaining structure 101 in embodiments of machine 100 comprising a retaining structure 101. In some embodiments of machine 100 not shown in the figures, the retaining device 3 comprises a flexing element housed longitudinally inside the forming tube 1 and attached at a first end to said forming tube 1. The actuating means are preferably associated with a second end of the flexing element and configured so that by their action they cause the displacement of said second end towards the first end of the flexing element to cause the passage of the retaining device 3 to the blocking position, such that with said displacement the flexing element bends and part of said flexing element moves into the interior of the forming tube 1 (from one wall to the opposite wall of the forming tube 1) blocking at least partially the inner passage section of said forming tube 1. In some embodiments of machine 100 not shown in the figures, in which the retaining means comprise one or more retaining devices 3, each retaining device 3 comprises a platform housed inside the forming tube 1, associated with the drive means, the platform being freely connected to the drive means via a non-vertical pivot axis, said platform being configured to rotate with RCbl nn / C7n7 / R / YIAI with respect to said axis of rotation in a controlled manner to cause the change of position of the retention device 3. The change of position of the platform can be carried out by means of an actuator, such as a cylinder. In other embodiments of machine 100 not shown in the figures, in which the retaining means comprise one or more retaining devices 3, each retaining device 3 comprises a platform housed inside the forming tube 1. The platform of each retaining device 3 is positioned on an inflatable chamber housed in the forming tube 1 such that the inflation of the inflatable chamber causes the platform to partially block the passage section of the forming tube 1. Preferably, the inflatable chamber is attached or glued to the platform and causes the platform to be in a horizontal position in the blocking position. The control unit 4 is responsible for controlling the actuation of the actuator or the inflation / deflation of the inflatable chamber. In other embodiments of machine 100 not shown in the figures, in which the retaining tool comprises one or more retaining devices 3, each retaining device 3 comprises an inflatable chamber that is at least partially housed in the forming tube 1. The drive means are configured to inflate said inflatable chamber 15 to cause the retaining device 3 to change position, the retaining device 3 at least partially blocking the passage section of the forming tube 1 when the inflatable chamber is inflated. The control unit 4 is responsible for controlling the inflation / deflation of the inflatable chamber.

Claims

1. A vertical packaging machine comprising a vertical forming tube (1) with a product inlet (11), a product outlet (12) downstream of the inlet (11), and an internal passage section, characterized in that the machine (100) further comprises retaining means associated with the forming tube (1) and comprising at least one retaining device (3) configured to move between a blocking position (P1) in which it at least partially blocks the internal passage section of the forming tube (1) between the inlet (11) and the outlet (12), and a release position (P2) in which it does not block said internal passage section of the forming tube (1), the retaining device (3) being in the blocking position (P1),arranged at a fixed height with respect to the outlet (12) of the forming tube (1) and configured to prevent the passage of a product through said inner passage section of the forming tube (1), and said retaining device (3) being further configured so that, when passing from the locking position (P1) to the release position (P2), it is at least partially withdrawn from the path to be taken by said product through said inner passage section of the forming tube (1).

2. Vertical packaging machine according to claim 1, wherein the retention means comprise a plurality of retention devices (3), each retention device (3) being configured to move between a respective locking position (R1) in which it at least partially blocks the inner passage section of the forming tube (1) and a respective release position (P2) in which it does not block said inner passage section of the forming tube (1), each retention device (3) being arranged at a fixed determined height with respect to the outlet mouth (12) of said forming tube (1) in the respective locking position (P1), and said fixed determined heights being different from each other.

3. Vertical packaging machine according to claim 2, wherein the retention means further comprise a drive element (32) associated with each retention device (3), said drive element (32) being movable inside the forming tube (1) when said retention device (3) changes position between the locking position (P1) and the release position (P2); at least one movable belt (31) that moves together with the drive element (32), such that a section of said movable belt (31) associated with said drive element (32) is extended inside the forming tube (1), at least partially blocking the inner passage section of the forming tube (1) when the corresponding retention device (3) is in the locking position (P1); and drive means configured to cause the change of position of the retention device (3).

4. Vertical packaging machine according to claim 3, wherein at least one retaining device (3) is configured to move in a first direction (D1) inside the forming tube (1) to move to the locking position (P1) and in a second direction (D2) opposite to the first direction (D1) to move to the release position (P2), and at least one retaining device (3) is configured to move in the second direction (D2) inside the forming tube (1) to move to the locking position (P1) and in the first direction (D1) to move to the release position (P2), the retaining means being configured such that one of said retaining devices (3) is in the locking position (P1) when the other retaining device (3) is in the release position (P2).

5. Vertical packaging machine according to claim 4, wherein the retention means comprise at least one retention assembly (200) comprising a first retention device (3) and a second retention device (3) longitudinally distributed along the length of the forming tube (1), the first retention device (3) being the retention device furthest from the outlet (12) of the forming tube (1) and the second retention device (3) being the retention device closest to the outlet (12) of the forming tube (1), said retention assembly (200) further comprising a joining unit (33) configured to join together the two drive elements (32) associated with the two retention devices (3) of said retention assembly (200), and said joining unit (33) comprising a pivot axis (330) fixed with respect to the forming tube (1) for,By rotating the joining unit (33) about the pivot axis (330), simultaneously change the position of the first retaining device (3) and the second retaining device (3).

6. Vertical packaging machine according to claim 5, wherein the retention means comprise a plurality of retention assemblies (200) distributed along the length of the forming tube (1) one after the other and the same movable band (31) associated with all the retention devices (3), such that all the retention devices (3) move simultaneously.

7. Vertical packaging machine according to claim 5, wherein the retention means comprise a plurality of retention assemblies (200) distributed along the length of the forming tube (1) one after the other and a number of movable bands (31.1, 31.2) equal to the number of retention assemblies (200), a first movable band (31.1) being associated with the first retention device (3) of the retention assembly (200) furthest from the outlet (12) of the forming tube (1) and with the second retention device (3) of the retention assembly (200) arranged closer to said outlet (12), and each of the remaining movable bands (31.2) associated with the second retaining device (3) of a retaining assembly (200) and the first retaining device (3) of the retaining assembly (200) that is arranged adjacent to and downstream of said retaining assembly (200), such that all the retaining devices (3) move together.

8. Vertical packaging machine according to claim 5, wherein the retention means comprise a plurality of retention assemblies (200) distributed along the length of the forming tube (1) one after the other and a movable band (31.2, 31.2) associated with each respective retention assembly (200), such that said retention means comprise a number of movable bands (31.2, 31.2) equal to the number of retention assemblies (200), each movable band (31.2, 31.2) being associated with the first retention device (3) and the second retention device (3) of the associated retention assembly (200), and the drive means being configured to cause the simultaneous displacement of the retention devices (3) of all the retention assemblies (200).

9. Vertical packaging machine according to claim 4, wherein the retention means comprise a plurality of retention devices (3) movable in the first direction (D1) to move to the locking position (P1), said retention devices (3) forming a first retention group, and a plurality of retention devices (3) movable in the second direction (D2) to move to the locking position (P1), said retention devices (3) forming a second retention group, the retention devices (3) of the first retention group and of the second retention group being arranged alternately along the length of the forming tube (1), and the movable belt (31) being associated with all the drive elements (32) or the movable belt (31.1) being associated with all the drive elements (32) of the first retention group and the retention means comprising a second movable belt (31.2) associated with all the drag elements (32) of the second retention group; the retention devices (3) of the first retention group being configured to be in the locking position (P1) when the retention devices (3) of the second retention group are in the release position (P2) and vice versa, the drive means being configured to cause the simultaneous displacement of the retention devices (3).

10. Vertical packaging machine according to claim 9, wherein the retention means comprise a joining unit (33) attached to all the drive elements (32) of the retention devices (3) of the first retention group and the second retention group, such that the retention means are configured so that all the retention devices (3) move simultaneously.

11. Vertical packaging machine according to claim 3, wherein the moving belt (31) is associated with all the drag elements (32) and the retention means are configured so that all the retention devices (3) change position simultaneously.

12. Vertical packaging machine according to claim 11, wherein the retention means further comprise a joining unit (33) that joins all the drive elements (32) together.

13. Vertical packaging machine according to any of claims 3 to 12, wherein the drive means comprise at least active means (37.1) acting on at least one of the moving elements RPbl nn / C7n7 / R / YIAI during the change of position of a holding device (3), or at least active means (37.1) and at least passive means (37.2) acting on at least one of said elements.

14. Vertical packaging machine according to any of claims 1 to 13, comprising a retaining structure (101) housed in and fixed to the forming tube (1), the retaining means being attached to the retaining structure (101) such that said retaining means are associated with the forming tube (1) through said retaining structure (101).

15. Vertical packaging machine according to claim 14, wherein the forming tube (1) or the retaining structure 10 (101) comprises first guiding means configured to guide the displacement of each drag element (32) and second guiding means configured to guide the section of the moving belt (31) associated with the drag element (32) that remains extended inside the forming tube (1) when the corresponding retaining device (3) is in the locked position (P1).

Images