EP3498616A1

EP3498616A1 - A package forming unit for forming sealed packages

Info

Publication number: EP3498616A1
Application number: EP18210494.3A
Authority: EP
Inventors: Franco Santi
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2017-12-13
Filing date: 2018-12-05
Publication date: 2019-06-19
Also published as: CN109941477A; WO2019115315A1; CN210162289U

Abstract

There is described a package forming unit (17) for forming packages (2) from an advancing tube (3) comprising at least one jaw assembly (18) for forming a respective package (2) from the advancing tube (3). The jaw assembly (18) comprises a pair (46) of interaction tabs (47) adapted to interact with the tube (3) for exerting a pulling force and being controllable between a first limit configuration and a second limit configuration and a cam follower (49) adapted to interact with a cam arrangement (50) and being coupled to the pair (46) of interaction tabs (47) for controlling the pair (46) of interaction tabs (47) between the first limit configuration and the second limit configuration. The cam arrangement comprises an initial cam portion (57) for controlling the pair (46) of interaction tabs (47) into the first limit configuration, the initial cam portion (57) having a guiding surface (58) for guiding the cam follower (49) so as to define the first limit configuration of the pair (46) of interaction tabs (57) and a delimiting surface (59) for limiting movement of the cam follower into a direction (D) transversal to and away from the guiding surface (58).

Description

TECHNICAL FIELD

The present invention relates to a package forming unit for forming sealed packages, in particular for forming sealed packages from a tube of a web of packaging material, even more particular for forming substantially parallelepiped sealed aseptic packages.
The present invention relates for the particular advantage to a package forming unit for forming sealed packages for packaging a pourable product, in particular a pourable food product.

BACKGROUND ART

As is known, many liquid or pourable food products, such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
A typical example is the parallelepiped-shaped package for liquid or pourable food products known as Tetra Brik Aseptic (registered trademark), which is made by sealing and folding a web of packaging material.
The web of packaging material has a multilayer structure comprising a base layer, e.g. of paper, covered on both sides with layers of heat-seal plastic material, e.g. polyethylene. In the case of aseptic packages for long-storage products, such as UHT milk, the web of packaging material also comprises a layer of oxygen-barrier material, e.g. an aluminum foil, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material forming the inner face of the package eventually contacting the food product.
Commonly, the web of packaging material comprises a repeated pattern, in particular a plurality of equally spaced images or decorations on the face of the base layer facing the outside of the packages.
Packages of the sort mentioned above are normally produced on fully automatic packaging apparatuses.
A typical packaging apparatus comprises a conveying device for advancing a web of packaging material along an advancement path, a sterilizing unit for sterilizing the web of packaging material, a tube forming device arranged within an aseptic chamber and being adapted to form a tube from the advancing web of packaging material, a sealing device for longitudinally sealing the tube along a seam portion of the tube, a filling device for continuously filling the tube with a pourable product and a package forming unit adapted to produce single packages from the tube of packaging material.
E.g. WO-A-2005012102 discloses such a package forming unit for producing single packages from the continuously filled tube.
The package forming unit comprises:

a plurality of jaw assemblies, each one having a respective jaw and a respective counter-jaw being configured to form, in cooperation with one another, a respective package from the, in use advancing, tube of packaging material; and
at least a first chain conveyor for advancing the plurality of jaws along a first endless path and at least a second chain conveyor for advancing the plurality of counter-jaws along a second endless path.

Each jaw assembly of the package forming unit further comprises a pair of interaction tabs adapted to interact, in use, with the tube from opposite sides thereof for selectively exerting a pulling force on the advancing tube and for promoting the folding of the tube and being moveable between a first limit configuration and a second limit configuration.
In particular, each pair of interaction tabs is configured to at least partially control advancement of the tube of packaging material such that the tube of packaging material is in "register", meaning that the repeated pattern present on the web of packaging material and, accordingly, on the tube of packaging material is formed, sealed and cut so as to ensure that each repeated pattern corresponds to one respective package.
Even though the printed decorations are equally spaced, the position of each printed decoration with respect to the position of the jaw assemblies may vary, in use, due to the varying deformations of the packaging material by the mechanical pressures exerted on it by the jaw assemblies, and due to the pulsating pressure of the pourable food product inside the tube of packaging material.
Therefore, each pair of interaction tabs needs to be controlled such to exert the needed pulling force onto the tube of packaging material for guaranteeing the tube of packaging material being in "register". In other words, each pair of interaction tabs is controlled such that each repeated pattern is correctly aligned with the respective jaw and counter-jaw. In this way, the tube of packaging material is sealed so that each package has the respective repeated pattern.
Therefore, the package forming unit comprises a cam arrangement having a moveable portion and being adapted to interact with a cam follower coupled to the pair of interaction tabs of the jaw assembly so as to control the pair of interaction tabs between the first limit configuration and the second limit configuration.
Even though the package forming unit disclosed in WO-A-2005012102 provides for satisfying operational results, a need is felt to further improve such package forming units.

DISCLOSURE OF INVENTION

It is therefore an object of the present invention to provide, in a straightforward and low-cost manner, an improved package forming unit.
According to the present invention, there is provided a package forming unit as claimed in claim 1.
Further advantageous embodiments of the packaging apparatus according to the invention are specified in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a packaging apparatus having a package forming unit according to the present invention, with parts removed for clarity;
Figure 2 is a schematic sectionized side view of a package forming unit according to the present invention, with parts removed for clarity;
Figure 3 is a perspective front view of a detail of the package forming unit of Figure 2, with parts removed for clarity;
Figure 4 is a perspective back view of a portion of the detail of Figure 3, with parts removed for clarity; and
Figure 5 is a perspective back view of the detail of Figure 3, with parts removed for clarity.

BEST MODES FOR CARRYING OUT THE INVENTION

Number 1 indicates as a whole a packaging apparatus for producing sealed packages 2 of a pourable food product, such as fruit juice, pasteurized milk, wine, tomato sauce, etc., from a tube 3 of a web 4 of packaging material. Each package 2 comprises a pair of transversal sealing bands 5 and a longitudinal seal 6.
Web 4 of packaging material has a multilayer structure (not shown), and comprises a layer of fibrous material, normally paper, covered on both sides with respective layers of heat-seal plastic material, e.g. polyethylene.
Preferably, web 4 also comprises a layer of gas- and light-barrier material, e.g. aluminum foil or ethylene vinyl alcohol (EVOH) film, and at least a first and a second layer of heat-seal plastic material. The layer of gas- and light-barrier material is superimposed on the first layer of heat-seal plastic material, and is in turn covered with the second layer of heat-seal plastic material. The second layer of heat-seal plastic material forms the inner face of package 2 eventually contacting the food product.
Furthermore, web 4 also comprises a repeated pattern, in particular a plurality of equally spaced images or decorations on the face of the layer of fibrous material facing the outside of the packages.
With particular reference to Figure 1, packaging apparatus 1 comprises:

conveying means 7 for advancing at least web 4 along its longitudinal axis along a web advancement path P from a delivery station 8 to a tube forming station 9, at which, in use, web 4 is formed into tube 3;
an isolation chamber 10 separating an inner environment, in particular an inner aseptic environment, from an outer environment;
a tube forming device 14 extending along a longitudinal axis L, in particular having a vertical orientation, and being arranged, in particular at tube forming station 9, at least partially, preferably fully, within isolation chamber 10 and being adapted to form tube 3 from the, in use, advancing web 4;
a sealing device 15 at least partially arranged within isolation chamber 10 and being adapted to longitudinally seal tube 3 formed by tube forming device 14;
filling means 16 for continuously filling tube 3 formed by tube forming device 14 with the pourable product; and
a package forming unit 17 adapted to form packages 2 from the, in use, advancing tube 3 formed by tube forming device 14 and filled by filling means 16.

Preferably, packaging apparatus 1 also comprises a sterilizing unit adapted to sterilize the, in use, advancing web 4 at a sterilization station, in particular the sterilization station being arranged upstream of tube forming station 9 along path P.
With particular reference to Figure 1, conveying means 5 are also adapted to advance tube 3 formed by tube forming device 14 along its longitudinal axis along a respective tube advancement path Q, in particular from tube forming device 14 to package forming unit 17.
Preferentially, conveying means 5 are also adapted to at least partially advance tube 3 and any intermediate of tube 3 along path Q. In particular, with the wording intermediates of tube 3 any configuration of web 4 is meant prior to obtaining the tube structure and after folding web 4 by tube forming device 14 has started. In other words, the intermediates of tube 3 are a result of the gradual folding of web 4 so as to obtain tube 3.
In particular, operation of conveying means 5 and operation of package forming unit 17 are synchronized with respect to one another.
Preferably, package forming unit 17 is arranged downstream of isolation chamber 10 and of tube forming device 14 along path Q. Even more preferably, package forming unit 17 is arranged below isolation chamber 10 and tube forming device 14.
Preferentially, package forming unit 17 comprises:

a plurality of jaw assemblies 18 (only one shown in Figure 2), each having one respective jaw 19 and one respective counter-jaw 20 for forming in cooperation with one another a package 2 from the, in use, advancing tube 3;
at least a first chain conveyor 21 configured to advance jaws 19 along a first endless path R; and
at least a second chain conveyor 22 configured to advance counter-jaws 20 along a second endless path S, in particular distinct (different) from first endless path R.

In more detail, first endless path R and second endless path S comprise respectively an operative portion R1 and an operative portion S1 at which respectively jaws 19 and counter-jaws 20 advance, in use, parallel and adjacent to and in the same direction of tube 3 and interact with, in particular contact, in use, tube 3. In particular, jaws 19 advancing along operative portion R1 cooperate with the respective counter-jaws 20 advancing along operative portion S1 for forming the respective packages 2. Even more particular, each jaw 19 and the respective counter-jaw 20 are configured to contact, in use, tube 3, in particular when advancing along respectively operative portion R1 and operative portion S1, from opposite sides thereof.
In even more detail, first endless path R and second endless path S also have respectively a return portion R2 and a return portion S2 at which respectively jaws 19 and counter-jaws 20 are distanced from tube 3 advancing along path Q. In particular, each jaw 19 advancing along return portion R2 and the respective counter-jaw 20 advancing along return portion S2 are taken back to respectively operative portion R1 and operative portion S1, in particular so as to form, in use, a new package 2.
With particular reference to Figure 2, chain conveyor 21 and chain conveyor 22 are arranged parallel to and spaced apart from one another, in particular leaving a gap 26 through which, in use, tube 3 advances.
More specifically, chain conveyor 21 and chain conveyor 22 each comprises a respective operative branch 27 (only partially shown) for defining respectively operative portion R1 and operative portion S1. In particular, operative branches 27 face one another.
Even more specifically, chain conveyor 21 and chain conveyor 22 each comprises a respective return branch 28 for defining respectively return portion R2 and return portion S2. In particular, return branches 28 (only partially shown) face away from one another.
More specifically, chain conveyor 21 comprises a plurality of elongated main bodies 29 (only one shown in Figure 2) each one carrying one respective jaw 19, in particular each main body 29 extends along an axis A transversal to first endless path R.
Preferentially, main bodies 29 are coupled to (connected to) one another so as to define an endless chain, in particular main bodies 29 define mutually articulated links of the above-mentioned endless chain.
Preferentially, chain conveyor 21 also comprises at least a pair of endless tracks 30 (only one shown in Figure 2) having a substantially vertical orientation and being arranged parallel to and spaced apart from one another and being configured to guide main bodies 29 (i.e. main bodies 29 move, in use, along endless tracks 30). In particular, each endless track 30 carries a portion of the respective operative branch 27 and the respective return branch 28.
More specifically, as shown in Figures 3 to 5, each main body 29 comprises a first end portion 31 and a second end portion 32 opposite to first end portion 31. Each first end portion 31 is coupled to one endless track 30 and the respective second end portion 32 is coupled to the other endless track 30.
Furthermore, each main body 29 comprises a plurality of roller elements 33, arranged in the proximity of the respective first end portion 31 and the respective second end portion 32 and engaging with one respective endless track 30 of the pair of endless tracks, in particular being configured to run on (being guided by) the respective endless track 30 in a manner known as such.
As chain conveyor 22 is similar to chain conveyor 21, we will only describe the differences between chain conveyor 21 and chain conveyor 22.
In particular, chain conveyor 22 differs from chain conveyor 21 in that the respective main bodies of chain conveyor 22 carry the respective counter-jaws 20. Additionally, the respective axes A are transversal to second endless path S.
With particular reference to Figures 2 to 5, each jaw 19 comprises a respective half-shell 34 being adapted to contact, in use, tube 3, in particular from a first side thereof, and the respective counter-jaw 20 comprises a respective counter-half-shell 35, in particular being complementary to the respective half-shell 34, and being adapted to contact, in use, tube 3, in particular from a second side thereof opposite to the first side. In particular, each half-shell 34 and the respective counter-half-shell 35 are adapted to form and shape in cooperation the respective package 2.
In particular, each half-shell 34 and each counter-half-shell 35 is adapted to be controlled between a respective working position in which the respective half-shell 34 and the respective counter-half-shell 35 contact, in use, tube 3 and a respective rest position in which the respective half-shell 34 and the respective counter-half-shell 35 are detached from tube 3 (they do not contact tube 3).
Even more particular, each half-shell 34 and each counter-half-shell 35 is adapted to be controlled into the working position with respectively the respective jaw 19 and the respective counter-jaw 20 advancing, in use, along respectively operative portion R1 and operative portion S1.
More specifically, each half-shell 34 and each counter-half-shell 35 is pivotably mounted to the respective main body 29, in particular in the area of a central portion 36, in particular interposed between the respective first end portion 31 and the respective second end portion 32, of the respective main body 29.
Furthermore, each jaw 19 and each counter-jaw 20 comprises a respective cam follower element 37 coupled to the respective half-shell 34 or the respective counter-half-shell 35 and being adapted to interact with a cam body 38 (known as such and not further described) of package forming unit 17 (only partially shown in Figures 3 and 5 to the extend necessary for the comprehension of the invention) so as to control the respective half-shell 34 or the respective counter-half-shell 35 between the respective working position and the respective rest position.
With particular reference to Figures 2 to 5, each jaw 19 also comprises one of a sealing element or a counter-sealing element (in the example shown a counter-sealing element 43 and the respective counter-jaw 20 comprises the other one of a sealing element or a counter-sealing element (in the example shown a sealing element 44). In particular, each sealing element 44 and the respective counter-sealing element 43 are adapted to transversally seal tube 3 in a known manner, in use, between adjacent packages 2, in particular so as to form a common sealing band 45 between two adjacent packages 2 (see Figure 1).
Preferably, each sealing element 44 and each counter-sealing element 43 is mounted to the respective main body 29, in particular in the area of the respective central portion 36.
In the specific example shown, each sealing element 44 and each counter-sealing element 43 is arranged downstream of respectively counter-half-shell 35 and half-shell 34 along respectively first endless path S and second endless path R.
In a preferred embodiment, each jaw 19 and the respective counter-jaw 20 also comprises one of a cutting element (not shown and known as such) or a counter-cutting element (not shown and known as such) for transversally cutting tube 3 between adjacent packages 2, in particular along the respective common sealing band 45 so as to separate adjacent packages 2 from one another and to obtain the respective sealing bands 5 of the two adjacent respective packages 2.
With particular reference to Figure 3 to 5, each jaw assembly 18 further comprises a pair 46 of interaction tabs 47 being adapted to interact, in use, with advancing tube 3 from opposite sides thereof, in particular for exerting a pulling force on, in use, advancing tube 3, even more particular for at least partially controlling advancement of tube 3, and being controllable (moveable) between a first limit configuration and a second limit configuration.
In particular, each pair 46 of interaction tabs 47 is configured to control advancement of tube 3 such that the tube of packaging material is in "register", meaning that tube 3 is formed and sealed, and in particular cut, at the intended region of the repeated pattern (in other words, tube 3 is advanced in such a manner that the package 2 obtained after sealing and, in particular after cutting, has the respective repeated pattern).
In other words, each pair 46 of interaction tabs 47 is adapted to exert a controlled pulling force on tube 3 so as to "pull" tube 3 in a downstream direction along path Q.
Furthermore, interaction tabs 47 are also configured to fold tube 3 by varying amounts towards common sealing band 45.
In particular, the controlled pulling force is dependent on how each pair 46 of interaction tabs 47 is controlled between the respective first limit configuration and the respective second limit configuration, i.e. the position of the interaction tabs 47 between the first limit configuration and the second limit configuration.
Preferentially, with the respective pair 46 of interaction tabs 47 being in the respective first limit configuration the respective interaction tabs 47 are, in use, detached (distanced) from tube 3 advancing along path Q, i.e. the respective interaction tabs 47 are not in contact with tube 3 and, thus, do not exert any pulling force on tube 3. In other words, when controlling the respective pair 46 into the respective first limit configuration the respective interaction tabs 47 are positioned such that they do not interact with tube 3 advancing along path P.
Preferably, with the respective pair 46 being in the respective second limit configuration the respective interaction tabs 47 are, in use, in contact with tube 3 advancing along path Q, in particular when being controlled into the second limit configuration the respective interaction tabs 47 exert a maximum pulling force on tube 3.
Furthermore, each pair 46 of interaction tabs 47 is configured such to be controllable between the first limit configuration and the second limit configuration so as to control the pulling force exerted by the respective interaction tabs 47 onto tube 3.
Furthermore, each jaw assembly 18 also comprises an actuation device 48 having a respective cam follower 49 adapted to interact with a cam arrangement 50 (only partially shown to the extent necessary for the comprehension of the invention) of package forming unit 17 and being coupled to the respective pair 46 of interaction tabs 47 for controlling, in particular continuously controlling, the respective pair 46 of interaction tabs 47 between the respective first limit configuration and the respective second limit configuration.
Preferentially, each cam follower 49 is controllable between a first limit position and a second limit position in which the respective pair 46 of interaction tabs 47 is respectively in its respective first limit configuration and its respective second limit configuration.
Preferably, each actuation device 48 also comprises a transmission assembly 51, in particular having an articulated inverted parallelogram configuration, coupled to the respective cam follower 49 and the respective pair 46 of interaction tabs 47 and configured to simultaneously transfer movement of the respective cam follower 49 induced by the interaction with cam arrangement 50 to the respective pair 46 of interaction tabs 47.
Preferentially, each pair 46 of interaction tabs 47 and the respective actuation device 48 are associated to, in particular are part of, one of the respective jaw 19 and counter-jaw 20 (in the specific case shown of the respective jaw 19). Accordingly, each pair 46 of interaction tabs 47 and the respective actuation device 48 are configured to advance along first endless path R or second endless path S, in the specific example shown along first endless path R. In particular, each pair 46 of interaction tabs 47 is configured to interact, in use, with tube 3, when advancing along the respective operative portion R1 or the respective operative portion S1.
Preferentially, each actuation device 48 also comprises a biasing assembly configured to bias the respective pair 46 of interaction tabs 47 into the respective first limit configuration, i.e. cam arrangement 50 is configured such to control the respective pair 46 of interaction tabs 47 against the action of the respective biasing assembly between the respective first limit configuration and the second limit configuration.
With particular reference to Figure 3, each pair 46 of interaction tabs 47 is mounted to one respective main body 29, in particular to a front side of main body 29, which, in particular, in use, faces advancing tube 3 when, in use, the respective pair 46 of interaction tabs 47 interacts with tube 3.
In more detail, each respective interaction tab 47 of each pair 46 is pivotally mounted to the respective main body 29.
Preferentially, each interaction tab 47 is adapted to angularly move around a respective rotation axis, in particular being normal to the respective axis A, between a respective outer limit position in which the respective interaction tab 47 is, in use, distanced from (not in contact with) tube 3 and a respective inner limit position in which the respective interaction tab 47 is, in use, in contact with tube 3.
In particular, the respective first limit configuration and the respective second limit configuration of each pair 46 of interaction tabs 47 is defined by the respective interaction tabs 47 being respectively in the outer limit position and the inner limit position.
In more detail, the pulling force exerted, in use, by each pair 46 of interaction tabs 47 interacting with tube 3 is dependent on the angular position of the respective interaction tabs 47. In particular, the pulling force is maximum with the respective interaction tabs 47 being angularly positioned in their respective inner limit position.
More specifically, the respective interaction tabs 47 of each pair 46 are arranged adjacent to and at opposite lateral sides of the respective half-shell 34 or the counter-half-shell 35. In particular, the respective interaction tabs 47 are arranged symmetrically with respect to the respective half-shell 34 or the respective counter-half-shell 35.
Even more specifically, the respective interaction tabs 47 of each pair 46 are arranged along a zone interposed between the respective counter-sealing element 43 or the respective sealing element 44 (in the specific case shown, the counter-sealing element 43) and the respective half-shell 34 or the respective counter-half-shell 35 (in the specific case shown the half-shell 34).
Furthermore, each interaction tab 47 comprises a respective engagement surface 56 adapted to engage tube 3 at varying contact angles in dependence of the angular position of the respective interaction tab 47.
With particular reference to Figures 4 and 5, each actuation device 48 is connected to the respective main body 29, in particular at a respective back side opposite to the respective front side.
With particular reference to Figures 3 and 5, cam arrangement 50 comprises:

a main cam portion (not shown and known as such) configured to interact with actuation devices 48, in particular cam followers 49, and to control through the interaction with actuation devices 48, in particular cam followers 49, the respective pairs 46 of interaction tabs 47 between the first limit configuration and the second limit configuration, in particular with the respective jaw 19 or the respective counter-jaw 20 advancing along respective operative portion R1 and operative portion S1; and
an initial cam portion 57 arranged upstream of the main cam portion along first endless path R or second endless path S (depending on whether pair 46 is associated to the respective jaw 19 or the respective counter-jaw 20) for interacting with actuation devices 48, in particular cam followers 49, such to control the respective pairs 46 of interaction tabs 47 into the first limit configuration.

Preferentially, cam arrangement 50 is interposed between the respective endless tracks 30. Preferably, the main cam portion extends substantially parallel to path Q.
In more detail, the main cam portion comprises an engagement surface along which cam followers 49 advance, in use, so as to control the pairs 46 of interaction tabs 47 between the respective first limit configurations and the second limit configurations, in particular when, in use, advancing along a downstream section of the respective operative portion R1 or the respective operative portion S1.
Preferably, the main cam portion comprises at least one moveable section coupled to an actuation device (known as such and not further described) of cam arrangement 50 adapted to vary the position of the moveable section so as to control the angular positions of interaction tabs 47. Thus, the force exerted by pairs 46 of interaction tabs 47 interacting, in use, with tube 3 is controlled by moving the moveable section in a manner known as such.
In more detail, initial cam portion 57 is configured to interact with cam followers 49 such that interaction tabs 47 are arranged at a defined angular position in which interaction tabs 47 are detached from tube 3.
In particular, initial cam portion 57 is configured to position cam followers 49 in the respective first limit position.
Advantageously, initial cam portion 57 comprises:

a guiding surface 58 for guiding cam followers 49 so as to define the first limit position of cam followers 49 (and, accordingly, to define the first limit configuration of pairs 46 of interaction tabs 47); and
a delimiting surface 59 adjacent to and facing guiding surface 58 and configured to limit movement of cam followers 49 along a direction D transversal to and away from guiding surface 58.

In particular, delimiting surface 59 allows to limit movement of cam followers 49 so as to ensure that pairs 46 of interaction tabs 47 remain in the first limit configuration (and do not accidentally move towards the second limit configuration). In more detail, delimiting surface 59 allows to limit movement of cam followers 49 so as to ensure that interaction tabs 47 remain in an angular position in which interaction tabs 47 are distanced (detached / do not contact) tube 3, in particular when advancing along an upstream section of the respective operative portion R1 or the respective operative portion S1; the upstream section being arranged upstream of the respective downstream section along the respective first endless path R or the respective second endless path S.
It should be noted that without delimiting surface 59 pairs 46 of interaction tabs 47 could move in a non-controllable manner towards the second limit configuration. This again could lead to a positioning of the respective interaction tabs 47 so that these could get in a non-controlled manner into contact with tube 3.
Preferentially, delimiting surface 59 is configured to limit movement of cam follower 49 along direction D transversal to an advancement path along which cam followers 49 advance, in use (the advancement path being substantially first endless path R or second endless path S, i.e. the advancement path is determined by movement of the respective main body 29 and the interaction with cam arrangement 50).
Preferably, guiding surface 58 is placed directly upstream of the engagement surface of the main cam portion along first endless path R or second endless path S. In other words, when cam followers 49 advance, in use, along their respective advancement path at first cam followers 49 engage with guiding surface 58 and then with the engagement surface of the main cam portion.
In further detail, initial cam portion 57 comprises a first cam bar 60 carrying the guiding surface 58 and a second cam bar 61 spaced apart from and arranged substantially parallel to cam bar 60 and carrying the delimiting surface 59.
In use, web 4 advances along path P through isolation chamber 10 and is formed into tube 3 advancing along path Q.
Tube 3 advances along path Q to and through package forming unit 17.
Package forming unit 17 forms packages 2 from advancing tube 3.
In more detail, jaw assemblies 18 interact with tube 3 for forming packages 2.
In even more detail, each jaw 19 and the respective counter-jaw 20 advance along respectively first endless path R and second endless path S. Each jaw 19 and the respective counter-jaw 20 interact with tube 3 while advancing respectively along operative portion R1 and operative portion S1.
More specifically, while each jaw 19 advances along operative portion R1 and while the respective counter-jaw 20 advances along operative portion S1, the respective half-shell 34 and the respective counter-half-shell 35 are controlled into the respective working position for forming in cooperation tube 3 for obtaining the respective package 2. Preferentially, the respective sealing element 44 and the respective counter-sealing element 43 seal tube 3 so as to form the respective common sealing band 45. Preferably, after formation of the respective common sealing band 45 the respective cutting element and the respective counter-cutting element cooperate so as to transversally cut tube 3 along the respective common sealing band 45 so as to separate the respective two adjacent packages 2.
Furthermore, each pair 46 of interaction tabs 47 interacts with tube 3, in particular for exerting the required pulling force for keeping the repeated patterns "in register".
In particular, during advancement of the respective jaw 19 (or in the alternative case of the respective counter-jaw 20) the respective pair 46 of interaction tabs 47 are controlled between the first limit configuration and the second limit configuration, in particular by controlling the respective cam follower 49 between the respective first limit position and the second limit position.
In particular, cam follower 49 interacts with cam arrangement 50 so as to control the respective pair 46 of interaction tabs 47.
Prior to interaction of the respective jaw 19 with tube 3, the respective pair 46 of interaction tabs 47 is controlled into the respective first limit configuration by the respective cam follower 49 being guided by guiding surface 58 delimiting surface 59. In particular, guiding surface 58 guarantees that the respective cam follower 49 remains in the first limit position. Then, the respective cam follower 49 is guided, in particular in a controlled manner, by the engagement surface of the main cam portion so as to control the respective pair 46 of interaction tabs 47 between the respective first limit configuration and the respective second limit configuration in a manner known as such and not further described.
The advantages of package forming unit 17 according to the present invention will be clear from the foregoing description.
In particular, by providing delimiting surface 59 it is possible to guarantee that cam followers 49 remain in the first limit position prior to interaction of cam followers 49 with the main cam portion. Thus, this guarantees that pairs 46 of interaction tabs 47 remain in the first limit configuration prior to interaction of cam followers 49 with the main cam portion. This allows avoiding that the respective interaction tabs 47 unintentionally contact tube 3.
Clearly, changes may be made to packaging apparatus 1, in particular package forming unit 17 as described herein without, however, departing from the scope of protection as defined in the accompanying claims.

Claims

A package forming unit (17) for continuously forming sealed packages (2) from a tube (3) advancing along a tube advancement path (Q) comprising:
- at least one jaw assembly (18) having one respective jaw (19) and one respective counter-jaw (20) for forming in cooperation with one another a respective package (2) from the, in use, advancing tube (3);

- at least a first chain conveyor (21) for advancing the jaw (19) along a first endless path (R); and

- at least a second chain conveyor (22) for advancing the counter-jaw (20) along a second endless path (S);
wherein the jaw assembly (18) further comprises:
- at least one pair (46) of interaction tabs (47) associated to one of the respective jaw (19) or the respective counter-jaw (20) and being adapted to interact, in use, with the tube (3) from opposite sides thereof and being controllable between a first limit configuration in which the respective interaction tabs (47) are configured to be, in use, detached from the tube (3) and a second limit configuration in which the respective interaction tabs (47) are configured to be, in use, in contact with the tube (3); and

- an actuation device (48) having a cam follower (49) adapted to interact with a cam arrangement (50) of the package forming unit (17) and being coupled to the pair (46) of interaction tabs (47) for controlling the pair (46) of interaction tabs (47) between the first limit configuration and the second limit configuration;
wherein the cam arrangement (50) comprises:
- an initial cam portion (57) for interacting with the actuation device (48) such to control the pair (46) of interaction tabs (47) in the first limit configuration; and

- a main cam portion arranged downstream of the initial cam portion (57) along the respective first endless path (R) or the respective second endless path (S) and being configured to control the cam follower (49) such to at least control the pair (46) of interaction tabs (47) between the first limit configuration and the second limit configuration;
wherein the initial cam portion (57) comprises a guiding surface (58) for guiding the cam follower (49) so as to define the first limit configuration of the pair (46) of interaction tabs (57);
characterized in that the initial cam portion (57) further comprises a delimiting surface (59) adjacent to and facing the guiding surface (58) and configured to limit movement of the cam follower (49) along a direction (D) transversal to and away from the guiding surface (58).
The package forming unit according to claim 1, wherein the cam follower (49) advances, in use, along a respective advancement path and the delimiting surface (59) is configured to limit movement of the cam follower (49) into the direction (D) transversal to the advancement path.
The package forming unit according to claim 1 or 2, wherein the jaw (19) comprises a half-shell (34) and the counter-jaw (20) comprises a counter-half-shell (35);
wherein the half-shell (34) and the counter-half-shell (35) are configured to form in cooperation with one another the package (2) from tube (3);
wherein the respective interaction tabs (47) of the pair (46) of interaction tabs (47) are arranged adjacent to and at opposite lateral sides of one of the half-shell (34) or the counter-half-shell (35).
The package forming unit according to any one of the preceding claims, wherein each one of the first conveyor device (21) and the second conveyor device (22) comprises at least one respective elongated main body (29) for carrying respectively the jaw (19) and the counter-jaw (20);
wherein each interaction tab (47) of the pair (46) of interaction tabs (47) is mounted to one respective main body (49) and is adapted to angularly move around a respective rotation axis between a respective outer limit position and a respective inner limit position;
wherein the first limit configuration and the second limit configuration are defined by the interaction tabs (47) of the pair (46) of interaction tabs (47) being respectively in the outer limit position and the inner limit position.
The package forming unit according to any one of the preceding claims, wherein the actuation device (48) comprises a transmission assembly (51) coupled to the cam follower (49) and the pair (46) of interaction tabs (47) and configured to, in use, simultaneously transfer movement of the cam follower (49) induced by the interaction of the cam follower (49) with the cam arrangement (50) to the pair (46) of interaction tabs (47).
A packaging apparatus for forming sealed packages (2) of a pourable food product from a tube (3) of a web (4) of packaging material comprising:
- an isolation chamber (10) separating an inner environment from an outer environment;

- a tube forming device (14) being at least partially arranged within the isolation chamber (10) and being adapted to form the tube (3) from the, in use, advancing web (4) of packaging material;

- conveying means (7) adapted to advance the web (4) of packaging material along a web advancement path (P) to the tube forming device (14) and adapted to advance the tube (3) from the tube forming device (14) along a tube advancement path (Q);

- a sealing device (15) at least partially arranged within the isolation chamber (10) and being adapted to longitudinally seal the tube (3) formed by the tube forming device (14);

- filling means (16) for continuously filling the tube (3) formed by the tube forming device (14) with the pourable product; and

- a package forming unit (17) according to any one of the preceding claims being arranged downstream of the tube forming device (14) along the tube advancement path (Q) and being adapted to form the packages (2) from the tube (3).