MACHINE FOR FORMING BAGS WITH INFUSION OR EXTRACTION

PRODUCTS

Technical field This invention relates to a machine for forming bags with infusion or extraction products.

Background art

The type of bag according to the invention is obtained from a sheet of material obtained from metal films, such as, for example, aluminium, but the material which can be used may be different even though with features similar to metal films.

Individual powder or granular products, or composite mixtures of a main basic product and a secondary product such as, for example, an aromatising product, are inserted in this bag.

Each bag has a quadrangular shape and is closed by three seals, two lateral and one at the top, whilst the bottom is created by folding the sheet in a "U" shape and has a partly embedded shape.

These bags usually have a lateral line of weakness close to the top sealing to allow the pull-off opening of the bag.

Automatic machines are used in order to obtain this type of bag as illustrated partly also in patent document WO2012/117308 and comprising:

- a station for feeding a continuous strip of packaging material along a feed direction; - a cutting station configured for separating single sheets from the continuous strip;

- a station for folding the single U-shaped sheet comprising a folding device and a first carousel, rotating about a first axis of rotation, equipped with radial grippers configured to each receive a corresponding sheet folded in a "U" shape and in such a way as to keep the closed bottom of the "U" of the individual sheet embedded towards the inside;

- a unit for sealing the two lateral edges of the sheet folded into a "U" shape; the sealing unit being positioned along the rotary path of the first carousel.

Some stations are added to this structure, in some machine solutions, such as:

- a second carousel, rotating about a second axis, equipped with a plurality of radial grippers configured to receive, each, the sheet folded in a "U" shape and sealed at the sides; the sheet is positioned on the corresponding gripper with its open end or mouth towards the outside of the gripper; the second carousel rotates about the second axis to define an arc-shaped path for each gripper so as to allow the reaching of a series of further stations in succession, that is to say:

- a station for dosing at least one infusion product fed through the open mouth of the U-shaped sheet comprising at least one dosing device;

- a station for closing, by sealing, the mouth of the sheet;

- a station for cutting excess material present between the sealing line and the free end of the sheet or bag thus formed using a cutting element;

- a station for collecting formed bags.

It should be noted that there may be two stations for sealing the sheet one after another. The first station performs an ultrasonic sealing using a unit comprising a sonotrode, whilst the second station performs a thermal sealing, superposed on the first sealing, in order to guarantee a secure closing line.

Moreover, at least the group of stations positioned close to the second carousel and the second carousel itself are arranged in a closed space and in a controlled atmosphere or environment (through the presence of nitrogen) to maintain a high level of the integrity of the product inserted in the sheets and in such a way as to increase the times for integrity of the bags themselves, since they will have a predetermined quantity of nitrogen inside them. The cutting station, which is particularly relevant to the invention, comprises a cutting tool having a body for supporting two opposite heads defining a punch (provided with a blade) and a die shaped to match to allow separation of the excess material on the bag.

At least one of the two heads (usually the cutting punch) is articulated to the body in such a way as to rotate between a non-operating position, wherein a first head is in a position away from the second head, and an operating position for cutting wherein the first head is rotated and in contact with the second head with the interposing of the material to be separated from the rest of the sheet.

The supporting body is fixed and positioned radially relative to the second axis of rotation of the second carousel in such a way as to position the two heads (in an operating position) partly inside the outer edge of the carousel (outer edge being defined by a virtual circular arc the radius of which is given by the sum of the length of each gripper and the length of the portion of sheet protruding from each gripper).

The heads are therefore interfering, in the operating position, during the passage of each gripper with the sheet closed to allow the sheet to be intercepted and to obtain the cutting of the excess material.

However, the cutting tool made up in this way has several drawbacks due in particular to the fixed structure of the supporting body and the position of the two operating heads.

The fixed structure of the body relative to the carousel and to the grippers is not very flexible, since if the dimensions of the bags are changed on the machine and therefore also the size of the waste material to be cut, it is necessary to act on the body in order to be able to modify its position relative to the position of the grippers passing, with relatively long setting times, in view of the presence of the controlled atmosphere in which the cut is positioned.

The positioning of the heads within the outer edge of the carousel forces the head(s) to have a very large angle of opening to allow the passage of the gripper with the bag before cutting.

It has been found that this large angle of opening of the heads makes it difficult for precise cuts to be made in the material of the sheet and, above all, uncertainty in the total separation of the waste material from the sheet. In this situation, the waste material might remain partly connected to the sheet (thus creating a hypothetical waste) or might remain positioned on one of the cutting heads and then cause problems for subsequent cutting. To this must be added the fact that any waste material cut incorrectly falls freely on the bottom of the machine and inside the zone with controlled atmosphere; this factor therefore requires machine stoppages for cleaning the operating zone.

Aim of the invention

The aim of the invention is to provide a machine for forming bags with infusion or extraction products which overcomes the above-mentioned drawbacks of the prior art.

More specifically, the aim of this invention is to provide a machine for forming bags for infusion or extraction products which can increase the production quality of the bags and the productivity of the machine through greater flexibility of the cutting station.

A further aim of the invention is to provide a machine for forming bags with infusion or extraction products which is able to rationalise the collection of the waste material generated by the cutting station.

Said aims are fully achieved by the machine for forming bags with infusion or extraction products according to the invention, as characterised in the appended claims.

Brief description of the drawings

These and other features of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment of it, with reference to the accompanying drawings, in which: - Figure 1 is a schematic front view, with some parts cut away to better illustrate others, of a machine for forming bags with infusion or extraction products according to the invention;

- Figure 2 is a perspective view, with some parts cut away to better illustrate others, of an enlarged detail of Figure 1 , in particular a station for cutting bags positioned close to a carousel for moving bags;

- Figures 3 and 6 are schematic front views of a succession of positions which can be actuated by the cutting station of Figure 2;

- Figure 7 is a schematic front view of a bag obtained with the machine of the preceding drawings.

Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, and in particular with reference to Figure 1 , the machine according to the invention, labelled 100 in its entirety, is used for forming bags 1 containing infusion or extraction products.

These bags 1 (for example, the one illustrated in Figure 7) are made, as described in more detail below, from single sheets of wrapping material obtained from metal films, such as, for example, aluminium, or from different material even if they have similar properties to metal films.

As illustrated, the machine 100 comprises a station 2 for forming and feeding single sheets 3 of wrapping material.

Again as illustrated, the machine 100 comprises a station 4 for U-shaped folding of the single sheet 3 comprising a folding device 5 and a first carousel 6, rotating about a first axis 6X of rotation.

The first carousel 6 is equipped with a plurality of radial grippers 7 configured to each receive a corresponding single sheet 3.

The machine 100 also comprises a unit 8 for sealing two lateral edges 3a and 3b of the single sheet 3, positioned in the corresponding gripper 7, in such a way as to form a sheet 3 with a closed bottom 3c for folding and the two closed sides 3a and 3b for sealing. Again as illustrated, the machine 100 comprises a second carousel 9, rotating about a second axis 9X of rotation, equipped with a plurality of radial grippers 10 configured to each receive the individual sheet 3.

The single sheet 3 is positioned on the corresponding gripper 10 with one end or mouth 3d open towards the outside of the gripper 10.

As illustrated, the second carousel 9 rotates about the second axis 9X to define a circular path P for each gripper 10 so as to allow a series of further stations to be reached in succession and along a feed direction A. The stations reached by the grippers 10 are the following, along the feed direction A.

A dosing station 11 comprising at least one device 12 for dosing an infusion or extraction product fed through the open opening 3d of the single sheet 3.

A first station 13 for closing the opening 3d of the single sheet 3 protruding from the gripper 10, by means of a transversal sealing line L.

A station 14 for cutting an edge 3e of excess material present between the transversal sealing line L and the free end of the sheet 3 or bag 1 formed in this way using a cutting element 15 positioned radially relative to the second axis 9X of rotation of the second carousel 9.

As illustrated (see also Figures 2 to 6) the cutting element 15 comprises a supporting body 16 for a first contact head or die 17 and a second cutting head or punch 18 positioned facing the die 17.

The cutting element 15 also comprises an actuator 19 interposed between the die 17 and the punch 18 and the supporting body 16.

The actuator 19 is configured for moving, in both directions, the die 17 and the punch 18, relative to the supporting body 16, along a rectilinear and radial trajectory relative to the second axis 9X of rotation between a first withdrawn non-operating position, wherein the die 17 and the punch 18 are moved away from the edge 3e of material in excess of the bag 1 positioned at the cutting station 14 (Figures 3 and 6), and a second advanced operating position, wherein the die 17 and the punch 18 are brought close to each other and intercept the edge 3e of material in excess of the bag 1 , so as to separate the edge 1 of material in excess (Figures 4 and 5).

The cutting element 15 also comprises a kinematic unit 20 connected to the die 17 or to the punch 18 and configured for moving them between a first open non-operating position, wherein the die 17 and the punch 18 are spaced apart (Figures 3, 4 and 6), at least at the first withdrawn non operating position of the actuator 19, and a second closed operating position, wherein the die 17 and the punch 18 are in contact with each other, with interposed the excess edge 3e to be cut, at least at the second advanced operating position of the actuator 19.

In other words, the cutting unit is located, in a non-operating position, spaced from the path P followed by the grippers with the bag being formed on board. The element is activated and moves towards the bag only when the gripper is in front of the cutting element.

This axial translation operating mode allows the cutting element to be structured with a reduced movement of the die and punch towards and away from each other, since they are positioned in front of the gripper in such a way as to superpose the edge to be cut.

To this must be added the fact that the step of withdrawal of the die and punch after cutting the excess edge determines a secure complete detachment of the excess edge from the bag, thanks to its retaining inside the die and the punch.

Moreover, the presence of the actuator increases the flexibility of use of the cutting element, as the stroke of the die and punch towards each other can be modified according to the size of the bag, that is to say, the excess quantity of edge to be cut.

It should be noted that the station 2 for forming individual sheets 3 may comprise a station 31 for feeding a continuous strip of wrapping material (comprising a reel 31b) and a cutting station 32 configured for separating the individual sheets 3 from the continuous strip. The above-mentioned unit 8 for sealing the sides 3a and 3b of the sheet 3 may be, in a first embodiment, along the path of the first carousel 6 and close to the first carousel 6 (see the dashed line block in Figure 1) or, in a second embodiment, again along the path of the first carousel 6, but inserted directly on the carousel 6.

The second embodiment of the sealing unit 8 may comprise one or more sealing units positioned on each of the plurality of radial grippers 7 present on the first rotary carousel 6. In this way, the transport times can also be used for sealing the sides 3a and 3b of each sheet 3 directly on each gripper 7.

Preferably, the machine 100 also comprises an intermediate carousel 33 for the passage of the individual sheets 3 from the first carousel 6 (after the lateral folding and sealing of the individual sheet 3) to the second carousel 9.

Preferably, the kinematic unit 20 is equipped with a unit 21 for transmitting motion connected to the supporting body 16 in such a way as to coordinate the movement of the die 17 or the punch 18 between the first open non-operating position and the second closed operating position, and vice versa, at the activation of the actuator 19 between the first withdrawn non-operating position and the second advanced operating position, and vice versa.

In light of this and without limiting the scope of the invention, the die 17 is fixed to a rigid support 22 and the punch 18 is connected to the kinematic unit 20 and is movable towards and away from the die 17.

Preferably, the above-mentioned motion drive unit 21 comprises a connecting rod-crank mechanism (see Figures 2 to 6).

The crank 21a is associated with a shaft 27, freely rotatable about its axis 27X, and connected to a column 28 forming part of the supporting body 16.

The connecting rod 21b is articulated to the crank 21a, at its first end, and to an L-shaped lever 29 defining the kinematic unit 20 for moving the punch 18 between the first open non-operating position and the second closed operating position through a rectilinear trajectory towards and away from the die 17.

More specifically, the L-shaped lever 29 is articulated at three different points: the first, upper, to lever 29, the second, lower, to the actuator 19, and the third, lateral, to the punch 18.

This configuration allows the punch 18, slidably constrained to a pair of fixed cylinders, to move towards and away from the fixed die 17.

Preferably, the die 17 and/or the punch 18 are connected to a suction unit 23 for retaining the cut excess edge 3e.

The suction unit 23 can be activated at least at the passage of the actuator 19 between its first non-operating position and its second operating position.

In light of this, the die 17 has an open inner area connected to the suction unit 23 for collecting the cut excess edge 3e.

It should be noted that the suction unit 23 comprises a fixed support 22 to which the die 17 is associated and in which a suction channel 23c is made which extends from the open inner area of the die 17.

The support 22 comprises a lower slide base 22s slidable along a wall 24 forming part of a box-shaped collector 25 for picking up and unloading the cut excess edge 3e towards a collecting point (not illustrated).

The slide base 22s therefore adapts to the movement of the die 17, however keeping the connection with the box-shaped collector 25 at all times.

Preferably, the punch 18 is connected to a unit 30 for generating a flow of air passing through a plurality of through holes made on the punch 18 to allow the retaining of the cut excess edge 3e by the pushing of the cut excess edge 3e on the die 17.

The flow of air also allows the pushing of the excess edge 3e towards the discharge channel 23c.

Preferably, the die 17 and the punch 18 are also configured for removing a flap of material on one side 3a or 3b of the bag 1 (during the step for cutting the excess edge 3e) in such a way as to define a weakened zone Zl of the bag 1 to allow a tear-type opening (see Figure 7).

It should be noted that the die 17 and the punch 18 may have different cutting geometries depending on the type of bag 1 to be obtained.

Figure 7 illustrates a cutting configuration wherein the bag 1 is obtained with the slightly curved top, but it may be obtained with a rectilinear head parallel to the closing seal (illustrated with a dashed line).

Preferable, the machine 100 comprises a second closing station 26 interposed between the first closing station 13 and the cutting station 14.

In light of this, the first closing station 13 comprises an ultrasonic sealing unit 13a to form the transversal closing line L of the individual sheet 3.

The second closing station 26 comprises a hot thermal sealing unit 26a to form a transversal sealing strip S superposed on the transversal closing line L of the single sheet 3.

The machine structured in this way therefore achieves the preset aims thanks to the axially movable cutting station.

This cutting element solution offers a series of advantages:

- a reduction in the extent of opening and closing movement of the die and of the punch with a reduction in the operating times and greater cutting quality;

- greater safety in the removal of the excess edge, thanks to the backward movement of the actuator with die and punch still in the near operating position, combined with the air flow units; - greater cleaning of the machine thanks to the suction channels which direct and discharge the excess cut edges towards zones outside the machine.