CN111746931A

CN111746931A - Opening device, package and method for applying an opening device to a wall of a package

Info

Publication number: CN111746931A
Application number: CN202010221786.5A
Authority: CN
Inventors: 安吉洛·索巴拉; 彼得罗·马提尼; 罗科·德保拉; 塞尔吉奥·雷斯卡卡奇亚里
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2019-03-26
Filing date: 2020-03-26
Publication date: 2020-10-09
Also published as: EP3715275A1; CN214139702U; WO2020193089A1

Abstract

The present invention relates to an opening device configured to be applied to a package containing a pourable product; the opening device comprises a cap configured to close a passage for the pourable product, said passage being accessible at an opening area of the package; the cap being movable towards and away from the open region in use to close and open the channel respectively; the opening means comprises a connecting element fitted to the cap and configured to fit to the package, thereby tethering the cap to the package and thereby defining a maximum distance the cap can be removed from the opening area in use. It also relates to a package comprising the opening device and a method of applying the opening device to a wall of a package.

Description

Opening device, package and method for applying an opening device to a wall of a package

Technical Field

The present invention relates to an opening device, in particular a reclosable opening device, configured to be applied to a package containing a pourable product, preferably a pourable food product.

The invention further relates to a method for applying an opening device to a package containing a pourable product, preferably a pourable food product.

Background

It is well known that many pourable food products, such as fruit juice, UHT (ultra high temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterile packaging material.

A typical example is a parallelepiped-shaped package for pourable food products, known as Aseptic Tetra Brik Aseptic (registered trademark), which is made by folding and sealing laminated packaging material.

In particular, the packaging material has a multilayer structure essentially comprising a base layer for stiffness and strength, which may be made of fibrous material (e.g. paper or mineral-filled polypropylene material), and a plurality of laminated layers of heat-seal plastic material (e.g. polyethylene film) covering both sides of the base layer.

In the case of aseptic packages for long-storage products, such as UHT milk or fruit juice, the packaging material also comprises a layer of gas-barrier material, for example aluminium foil or ethyl vinyl alcohol (EVOH) film, which is superimposed on a layer of heat-seal plastic material, in turn covered with another layer of heat-seal plastic material. This further layer of heat-seal plastic material forms the inner surface of the package eventually contacting the pourable food product.

Such packages are usually produced on fully automatic packaging machines, wherein a continuous tube is formed from a sheet-like packaging material.

Further, the sheet packaging material is sterilized in the packaging machine by using a chemical sterilizing agent, which is then removed after the sterilization is completed.

The sheet packaging material is then maintained in a closed, sterile environment and is folded and sealed longitudinally to form a tube.

To complete the forming operation, the tube is filled from above with the pourable food product by means of a duct, and is formed, sealed and subsequently cut along equally spaced cross sections.

Pillow packs are thus obtained, having longitudinal sealing bands, top transverse sealing bands and bottom transverse sealing bands, which are then folded mechanically to form respective substantially parallelepiped-shaped finished packages.

Alternatively, the packaging material may be cut into blanks, the blanks formed into packages on forming spindles, and the resulting packages filled with the food product and sealed. An example of such a package is the so-called "gable-top" package known under the trade name Tetra Rex (registered trade mark).

Various solutions have been proposed for opening the above-mentioned packages, one of which involves the use of reclosable opening devices made of plastic.

This type of opening device generally comprises:

-a frame defining an opening and fitted on a hole or pierceable or tearable portion on a wall of the package; and

a cap configured to be coupled to the frame so as to close the opening.

According to a known solution, the frame is fitted over a so-called pre-laminated hole, i.e. a hole formed only through the base layer, which hole is covered by other laminate layers of the packaging material (including the gas barrier material layer) by means of a lamination process.

In other words, the frame is assembled, usually glued, onto the pierceable portion of a pre-laminated hole made of such a laminated layer.

According to an alternative solution, the pierceable portion may be defined by a patch (patch) attached to the packaging material to close a hole formed in this case through the entire thickness of the packaging material.

Threaded opening devices are known in which the frame generally comprises an externally threaded substantially cylindrical collar, while the cap comprises an internal thread and is initially screwed onto the collar. Moreover, the cap is generally injection-moulded integrally with a relative anti-tamper ring (tamper-evidence ring) which is coaxially connected to the cap itself by means of a plurality of breakable bridges and which, once the bridges are broken and the cap is unscrewed, is destined to remain fitted to the collar.

It is known in the art that after unsealing the cap, i.e. detaching the cap from the tamper-evident ring and unscrewing the cap from the frame by applying a torque, the user must also remove (i.e. cut or tear) the pierceable portion covering the prelaminated hole in order to gain access to the package interior.

To this end, according to a known configuration, the opening means comprise a pull-off tab (pull-off) coupled to the pierceable portion and configured to be torn by the user once the cap is unscrewed from the frame.

According to an alternative solution, the known opening device comprises a substantially tubular cutting member screwed inside the collar and having an edge with a plurality of substantially triangular end teeth which cooperate with the pierceable portion and partially detach the pierceable portion from the opposite wall, preferably with the exception of a small-angle portion, so as to avoid the pierceable portion tearing after cutting from falling inside the package.

More precisely, the cutting member is actuated by the cap by means of a one-way ratchet-type transmission operated during disengagement of the cap from the collar of the frame. In detail, the cutting member is movable along a helical path with respect to the frame from a raised rest position, in which the end teeth face the pierceable portion, to a successively lowered cutting position, in which the end teeth interact with the pierceable portion so as to cut open the pierceable portion.

It is known in the art that there is an increasing need to reduce the environmental impact accompanying the packaging and bottling of food and non-food products. In particular, great care must be taken with the plastic parts of the packaging, as they can contaminate both aquatic and terrestrial environments.

Disclosure of Invention

It is therefore an object of the present invention to provide an opening device for packages containing pourable products, designed to meet the above-mentioned need in a simple and low-cost manner.

This object is solved by an opening device. The opening device is configured to be applied to a package containing a pourable product; the opening device comprises a cap configured to close a passage for the pourable product, said passage being accessible at an opening area of the package; the cap being movable towards and away from the open region in use to close and open the channel respectively; wherein a connecting element is included that is fitted to the cap and configured to fit to the package, thereby tethering the cap to the package and thereby defining a maximum distance that the cap can move away from the open area in use.

Another object of the present invention is to provide a method for applying an opening device to a package containing a pourable product, designed to satisfy the above-mentioned need in a simple and low-cost manner.

This object is achieved by a method for applying an opening device to a package. In particular, the present invention provides a method of applying an opening device to a wall of a package containing a pourable product; the method comprises the following steps: i) forming a package from a tube of packaging material; ii) providing a cap to close the passage for the pourable product available at the opening area of the wall; in particular comprising the following steps: iii) fitting a connecting element to the cap; and iv) fitting the connecting element to the package, thereby tethering the cap to the package and thereby defining a maximum distance that the cap can be removed from the wall in use.

Drawings

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

fig. 1 is a perspective view of the top of a sealed package containing a pourable product, fitted with an opening device according to a first embodiment of the present invention;

FIG. 2 is an enlarged side view in section of the opening device and package of FIG. 1 with portions omitted for clarity;

FIG. 3 is an enlarged side view in cross-section of a detail (indicated by the circle designated "D") of the opening device and package of FIG. 2, with portions omitted for clarity; and

fig. 4 is a perspective view of the top of a sealed package for containing a pourable product, equipped with an opening device according to a second embodiment of the present invention.

Detailed Description

With reference to fig. 1, numeral 1 indicates as a whole a package made of a multilayer sheet packaging material 2, suitable for containing a pourable product, and having a wall, in particular a top wall 4, on which an opening device 3 is fitted, the opening device 3 preferably being made of plastic material.

In particular, package 1 is suitable for containing pourable food products, such as milk, water, fruit juices, etc.

In the example shown, the opening device 3 is fitted on the opening area of the packet 1 by conventional fixing means, for example adhesive substances (such as glue), or by means of a welding system, for example laser welding or micro-flame welding.

Referring to fig. 2 and 3, the packaging material 2 comprises a base layer 5, which may be made of fibrous material (e.g. paper or mineral filled polypropylene material) for providing rigidity and strength, and a cover layer arrangement 6.

In detail, the cover layer means 6 comprise a first cover layer 6a and a second cover layer 6b, both made of heat-sealable plastic material (for example polyethylene film), and covering both sides of the base layer 5.

Packaging material 2 comprises, at top wall 4 of package 1, a pierceable portion 7, which pierceable portion 7 is externally covered, in use, by opening device 3 and is configured to be at least partially detached from top wall 4 so as to allow the pourable product to exit package 1.

In one embodiment, the pierceable portion 7 defines an opening area fitted with the opening means 3.

In another embodiment, not shown, the opening area may be a through hole formed in the packaging material 2, in particular in the portion of the packaging material 2 forming the top wall 4.

In the present case, the package 1 is an aseptic package for long-term storage of food products; correspondingly, the cover layer arrangement 6 also comprises a barrier layer 8 of a gas barrier material, for example an aluminium foil or an ethyl vinyl alcohol (EVOH) film, which barrier layer 8 is superimposed on the second cover layer 6b and in turn is covered with a third cover layer 6c of heat-seal plastic of the cover layer arrangement 6.

In particular, the third cover layer 6c forms the inner surface of the package 1 eventually containing the pourable food product.

In other words, in the production of the packaging material 2 in the form of a continuous sheet, the first cover layer 6a, the second cover layer 6b, the barrier layer 8 and the third cover layer 6c define a laminate layer which is applied to the base layer 5 by a lamination process, before it is cut and folded to form the package 1.

The pierceable portion 7 is defined by a through hole formed only through the base layer 5 and covered by the first cover layer 6a, the second cover layer 6b, the barrier layer 8 and the third cover layer 6 c.

In practice, the pierceable portion 7 is made of the laminated layer described above and closes the through hole formed in the base layer 5.

Preferably, the pierceable portion 7 is an integral part of the cover means 6.

According to an alternative embodiment, not shown, the pierceable portion 7 may be made of only one or more of the first cover layer 6a, the second cover layer 6b, the barrier layer 8 and the third cover layer 6 c. For example, the pierceable portion 7 may be made solely of the barrier layer 8.

In another alternative embodiment, not shown, pierceable portion 7 may be defined by a patch attached to packaging material 2 so as to cover a hole formed in this case through the entire thickness of packaging material 2.

The pierceable portion 7 has an axis a, preferably orthogonal to the top wall 4, which is vertical, in particular when the package 1 is erected on a bottom wall (not shown and substantially parallel to the top wall 4).

According to the non-limiting example shown, the pierceable portion 7 has a substantially circular shape concentric with the axis a.

Referring to fig. 1 to 3, the opening device 3 includes:

a frame 10 defining a passage 11 for the pourable product, and fitted around pierceable portion 7 on top wall 4 of package 1, passage 11 ending in an opening 11a through which opening 11a, in use, the pourable product is poured; and

a cap 12 configured to cooperate in contact with the frame 10 to close the channel 11 and the opening 11 a.

In detail, the opening 11a is arranged coaxially to the axis a, and the cap 12 is configured to engage the frame 10 coaxially to the axis a to close the passage 11.

More specifically, the frame 10 includes: a base plate 13, preferably flat, configured to be attached to the package 1 substantially parallel to the top wall 4 and around the pierceable portion 7; and a cylindrical collar 14 projecting crosswise, in particular orthogonally, from base plate 13 and having, in use, a longitudinal axis B coaxial with axis a. In particular, the collar 14 defines the passage 11 coaxially and internally. Therefore, the opening 11a is also arranged coaxially with the axis B.

The cap 12 comprises a substantially flat circular top wall 15 and a cylindrical wall portion 16, the cylindrical wall portion 16 projecting from the top wall 15 along the longitudinal axis C of the cap 12 itself and being configured to coaxially engage the collar 14 so as to close the passage 11.

For this purpose, the collar 14 is provided with an external thread 17 extending onto an outer lateral surface 18 of the collar 14 itself, and the cap 12 is provided with an internal thread 19 extending onto an inner lateral surface 20 of the cylindrical portion 16.

In detail, the external thread 17 and the internal thread 19 are configured to engage each other so as to determine, in use and under the action of the user, the loosening and tightening of the cap 12 with respect to the frame 10 (and therefore with respect to the collar 14), thus causing the opening and closing of the channel 11.

The opening device 3 further comprises a tamper-evident means, in particular a tamper-evident ring 21, which is preferably integrally formed with the cap 12, for example injection-molded together with the cap 12, and is initially coaxially connected to the rim 22 of the cap 12 by means of a plurality of frangible connecting bridges.

In detail, the cap 12 is initially fitted to the frame 10 in the closed position, in which the cap 12 is completely screwed onto the collar 14, with the edge 22 and the anti-detach ring 21 still connected to each other.

In more detail, the anti-detach ring 21 is fixed angularly with respect to the axes a and B, and once detached from the cap 12, the anti-detach ring 21 remains fixed angularly with respect to the axes a and B.

To this end, the collar 14 comprises a plurality of recesses 23, which recesses 23 are configured to engage with corresponding protrusions 23a of the tamper-evident ring 21.

In particular, the recesses 23 are circumferentially distributed on the collar 14 with respect to the axis B, and the protrusions 23a are circumferentially distributed on the tamper ring 21.

In the process of fitting the cap 12 to the frame 10, the tamper-evident ring 21 is fitted to the collar 14 such that the protrusions 23a face the recesses 23, thereby engaging the corresponding recesses 23.

More precisely, each recess 23 acts as a rotational and axial stop for the respective projection 23a, preventing angular movement, i.e. rotation, of the tamper ring 21 with respect to the axes a and B.

According to an alternative embodiment, not shown, the tamper ring 21 is rotatably fitted to the collar 14, i.e. it is free to rotate with respect to the collar 14.

Once unsealed, the cap 12 is movable between:

an open position in which the cap 12 is unscrewed from the collar 14 and detached from the frame 10; and

a closed position, in which cap 12 is screwed again on collar 14, closing channel 11 and opening 11 a.

During the first disengagement of the cap 12 from the collar 14, i.e. during the first movement of the cap 12 from its closed position to its open position, the connecting bridges initially connecting the tamper-evident ring 21 and the cap 12 break.

More specifically, after the cap 12 is first disengaged from the collar 14, each projection 23a of the tamper-evident ring 21 remains engaged in one of the corresponding recesses 23, which recesses 23 serve as rotational stops for such projections 23a, as described above.

These bridges break due to the resisting torque transmitted to them, releasing the cap 12 from the tamper-evident ring 21 and allowing it to be unscrewed from the collar 14.

In view of the above, the cap 12 is movable in use towards and away from the collar 14, i.e. towards and away from the opening area of the package 1, in order to close and open the passage 11, respectively.

According to the non-limiting embodiment shown, opening device 3 further comprises a known tubular cutting member 24, which cutting member 24 axially engages collar 14 in a movable manner and is actuated by cap 12 to interact with pierceable portion 7 to open package 1.

In detail, the cutting member 24 is provided with cutting means (known per se and not described in detail) and is connected to the collar 14 by means of guiding means (also known per se and not described in detail) such as a threaded element or a cam element and is configured to move between a raised rest position and a lowered open position during the first disengagement of the cap 12 from the collar 14.

In more detail, in the raised rest position, the cutting member 24 is completely housed inside the collar 14, with the cutting means facing the pierceable portion 7; in the lowered position, the cutting member 24 protrudes axially from the collar 14 so as to cut, penetrate and tear the pierceable portion 7 in a known manner, thereby allowing a fluid connection between the interior of the package 1 and the channel 11 (and also the opening 11 a).

The movement of the cutting member 24 is controlled in a known and not described in detail manner via a unidirectional angular transmission 25, which unidirectional angular transmission 25 is carried by the cap 12, in particular fitted on the top wall 15.

In an alternative embodiment not shown, the opening means 3 comprise a pull tab coupled to the pierceable portion 7 and configured to be pulled by the user once the cap 12 is unscrewed from the collar 14, in order to manually tear off the pierceable portion 7.

According to an important aspect of the present invention, the opening device 3 comprises a connecting element, in particular a strip 26, made of flexible material, in particular of flexible plastic material, fitted to the cap 12 and configured to be fitted to the frame 10, in particular to the frame 10 after the assembly of the opening device 3 is completed.

In this manner, the strap 26 tethers the cap 12 to the frame 10 and defines the maximum distance the cap 12 can be removed from the collar 14 and open area of the package 1 in use.

In detail, such maximum distance is substantially equal to the longitudinal extension of the strip 26.

The strip 26 is configured to allow unscrewing of the cap 12 from the collar 14 and to prevent removal (particularly separate disposal) of the cap 12 from the frame 10 (i.e. from the package 1).

As shown in fig. 1 and 2, the strap 26 includes:

a first end 27 fitted to the cap 12;

a second end 28 configured to be fitted to the frame 10, in particular to the frame 10 after completing the assembly of the opening device 3; and

a connecting portion 29 connecting the first end portion 27 to the second end portion 28.

In the example shown, the first end 27, the second end 28 and the connection 29 are integrally formed. In particular, the first end 27, the second end 28 and the connection 29 are obtained integrally from a sheet-like flexible plastic material, not shown, which is preferably more flexible than the plastic material forming the opening device 3.

According to an alternative embodiment, not shown, the strip 26 is made of a plurality of laminated layers of different flexible plastic materials.

According to this non-limiting preferred embodiment, the second end 28 is configured to be attached to the base plate 13, in particular to the base plate 13 after the assembly of the opening device 3 is completed.

Thus, the second end 28 is angularly fixed with respect to the axis B and also with respect to the axis a.

Preferably, the second end 28 is attached to a peripheral portion of the base plate 13 opposite the collar 14. In detail, such peripheral portion is the rear portion of the base plate 13 with respect to the pouring trajectory of the pourable product exiting from the package 1 in use.

Thanks to this configuration, during pouring of the pourable product out of package 1, cap 12 is prevented from moving in front of the pouring trajectory of the pourable product exiting from package 1, thereby avoiding undesired interferences between cap 12 and/or strip 26 and the pourable product exiting from package 1.

In fact, the strip 26 defines an area with a radius equal to the above-mentioned maximum distance of the caps 12 from the frame 10, in which the caps 12 can move away from and towards the frame 10 without interfering with the pourable product exiting from the channel 11 in use.

As shown in fig. 1 and 2, the first end 27 is attached to the top wall 15 of the cap 12.

In detail, the first end 27 is attached to the top wall 15 in an eccentric position with respect to the axis C. In this way, the strap 26 does not interfere with rotation of the cap 12 as the cap 12 is screwed/unscrewed from the collar 14.

In an alternative preferred embodiment, not shown, the first end 27 is attached to the cylindrical portion 16.

The opening device 3 of the above-described type is configured to be attached to the package 1 after filling, sealing and folding the package 1.

In detail, after the opening device 3 is applied to the top wall 4 of the package 1, the strip 26 may be applied to the opening device 3.

In more detail, after assembling the opening device 3 with the package 1, the first end 27 may be attached to the top wall 15 of the cap 12 and the second end 28 may be attached to the base plate 13.

Alternatively, the strip 26 may be applied to the opening device 3 before the opening device 3 is assembled with the package 1.

Furthermore, after assembling the opening device 3 with the package 1, the second end 28 may be attached to the base plate 13, while the first end 27 may have been attached to the top wall 15 of the cap 12.

The operation of the opening device 3 is described hereinafter with reference to fig. 1 and 2 and starting from a state in which the cap 12 is still screwed on the frame 10.

Starting from this condition, to open the package 1, the user unscrews the cap 12, causing the breakage of the connecting bridges of the tamper-evident ring 21 and the actuation of the cutting member 24, which determines the tearing of the pierceable portion 7.

The unscrewing action moves the cap 12 from its closed position to its open position.

As described above, during movement of the cap 12 from the closed position to the open position, the cap 12 is tethered to the frame 10 by means of the strap 26.

Once the desired amount of pourable product has been poured through channel 11, the user can close channel 11 by screwing cap 12 onto collar 14 again.

With reference to fig. 4, the numeral 3' generally designates an opening device assembled to the package 1 and made according to a second preferred embodiment of the present invention.

Since the opening device 3' is similar to the opening device 3, the following description is limited to the differences between them and, where possible, the same reference numerals are used for the same or corresponding parts and components.

In particular, the opening device 3 ' differs from the opening device 3 by comprising a strip 26 ', the strip 26 ' having a first end 27 ' and a second end 28 ', the first end 27 ' being attached to the top wall 15 of the cap 12, similarly to the first end 27 of the strip 26, the second end 28 ' being configured to be fitted directly on the top wall 4 of the packet 1, instead of on the base plate 13 of the frame 10.

In particular, after completing the assembly of the opening device 3 ', the second end 28' is fitted, preferably attached, to the top wall 4.

Thus, the second end 28' may be attached to the top wall 4.

The first end portion 27 ' and the second end portion 28 ' are connected to each other by a connecting portion 29 '.

In this second embodiment, the strip 26 'may be applied after the application of the opening device 3' to the top wall 4 of the package 1.

In more detail, after assembling the opening device 3 ' with the package 1, the first end 27 ' may be attached to the top wall 15 of the cap 12, while the second end 28 ' may be attached to the top wall 4.

Alternatively, the strip 26 ' may be applied to the opening device 3 ' before the opening device 3 ' is assembled with the package 1.

The advantages of the opening device 3, 3' according to the invention will be apparent from the foregoing description.

In particular, thanks to the presence of the strips 26, 26', the caps 12 are firmly tethered to the frame 10 and the risk of the caps 12 scattering in the environment after use of the packet 1 is always reduced, preventing plastic contamination of the environment deriving from the type of packet 1 described above.

In addition, since the first end 27, 27 'is attached to the top wall 15 eccentrically with respect to the axis C, the strip 26, 26' does not interfere with the normal operation and use of the opening device 3, 3 ', at least maintaining the same versatility as opening devices known in the art which are not provided with a strip 26, 26', while being more environmentally friendly.

Furthermore, the strips 26, 26 ' can be easily fixed to known opening devices 3, 3 ' before or after assembling the opening devices 3, 3 ' with the relative packages 1.

Therefore, the strips 26, 26 'do not require substantial modifications to the known opening devices 3, 3' in order to be implemented thereon.

Clearly, changes may be made to opening device 3, 3' as described herein without, however, departing from the protective scope as defined in the accompanying claims.

In particular, the frame 10 of the opening device 3 may be directly molded on the opening area of the package 1, for example by injection molding. In this case, a predetermined amount of molten plastic is injected by known molding means onto the pierceable portion 7 and through the pierceable portion 7. During moulding, due to the injection pressure and geometry of the moulding means used to form the opening device 3, the plastic material is pushed to pierce the pierceable portion 7 from a first side thereof, so as to pass through the pierceable portion 7, and to protrude from a second side of the pierceable portion 7, opposite to the first side. The laminate layer forming the pierceable portion 7 and closing the hole of the base layer 5 is first pierced and then resealed by the frame 10 formed of plastic material.

In this case, the finished package 1 is defined by an assembly comprising the filled, folded and sealed package 1 and a frame 10, which frame 10 has been injection-molded on the top wall 4 of the package 1, in particular at the opening area thereof. In other words, the frame 10 may be considered as part of the package 1 and the opening device 3. Thus, in this case, since the frame 10 is part of the packet 1, the strips 26, 26' are fitted to the cap 12 and to the top wall 4 of the packet 1, i.e. they fix the frame 12 to the packet 1.

Furthermore, the second end 28 of the strip 26 may be fitted between the frame 10 and the top wall 4, below the base plate 13 and above the portion of the top wall 4 covered by the base plate 13.

Claims

1. An opening device (3, 3') configured to be applied to a package (1) containing a pourable product; said opening device (3, 3') comprising a cap (12), said cap (12) being configured to close a passage (11) for said pourable product, said passage (11) being accessible at an opening area of said package (1);

said cap (12) being movable, in use, towards and away from said opening region to close and open said passage (11), respectively;

characterised by comprising a connecting element (26, 26 '), said connecting element (26, 26') being fitted to said cap (12) and configured to be fitted to said package (1), thereby tethering said cap (12) to said package (1) and thereby defining a maximum distance said cap (12) can be displaced from said opening area in use.

2. The opening device according to claim 1, wherein the connecting element (26, 26 ') comprises a first end (27, 27') fitted to the cap (12), a second end (28, 28 ') configured to be fitted to the package (1), and a connecting portion (29, 29') connecting the first end (27, 27 ') to the second end (28, 28').

3. The opening device according to claim 2, wherein the connecting portion (29, 29 '), the first end portion (27, 27 ') and the second end portion (pei28, 28 ') are integrally formed.

4. The opening device according to claim 2 or 3, wherein the passage (11) has a first longitudinal axis (A); and wherein the second end (28, 28') is configured to be angularly fixed with respect to the first longitudinal axis (a).

5. The opening device (3) according to any one of claims 2 to 4, and comprising a frame (10), the frame (10) defining the passage (11) and being fittable around the opening area; the cap (12) being configured to cooperate in contact with the frame (10) to close the channel (11);

wherein the connecting member (26) is configured to fit to the frame (10), thereby tethering the cap (12) to the frame (10).

6. The opening device according to claim 5, wherein the frame (10) comprises a base plate (13), which base plate (13) is fittable to a wall (4) of the package (1) having the opening area;

the second end (28) is attachable to the substrate (13).

7. The opening device of claim 5 or 6, wherein the cap (12) comprises a top wall (15) and a side wall (16), the side wall (16) protruding from the top wall (15) and being configured to engage the frame (10) to close the passage (11);

the first end (27) is attached to the top wall (15).

8. The opening device of claim 7, wherein the side wall defines a cylindrical portion (16), the cylindrical portion (16) being provided with a first thread (19) extending onto an inner side surface (20) thereof;

said frame (10) comprising a cylindrical collar (14) having a second longitudinal axis (B) and coaxially defining said passage (11);

said collar (14) being provided with a second thread (17) extending onto an outer surface (18) thereof and configured to engage with said first thread (19) in order to decide screwing/unscrewing of said cap (12) onto/from said collar (14);

the second end (28) is angularly fixed with respect to the second longitudinal axis (B) at least during screwing/unscrewing of the cap (12) onto/from the collar (14).

9. The opening device (3 ') according to any one of claims 2 to 4, wherein the second end (28 ') of the connecting element (26 ') is attachable to a wall (4) of the package (1) having the opening area.

10. The opening device according to any one of the preceding claims, wherein the connecting element (26, 26') is defined by a strip of flexible plastic material.

11. The opening device according to any one of the preceding claims, wherein the opening region defines an opening portion (7) of the package (1);

the opening device (3) comprises a cutting member (24), the cutting member (24) being configured to movably engage the passage (11) and being configured to cooperate in contact with the opening portion (7) to open the package (1).

12. A package (1) containing a pourable product and being obtained from a sheet packaging material (2) having an opening portion (7);

the package (1) comprising an opening device (3, 3 ') according to any one of the preceding claims and the opening device (3, 3') being fitted around the opening portion (7).

13. A method of applying opening devices (3, 3') to a wall (4) of a package (1), said package (1) containing a pourable product; the method comprises the following steps:

i) forming a package (1) from a tube of packaging material (2);

ii) providing a cap (12) to close the passage (11) for the pourable product available at the opening area of said wall (4);

the method is characterized by comprising the following steps:

iii) fitting a connecting element (26, 26') to said cap (12); and

iv) fitting said connecting element (26, 26') to said package (1), thereby tethering said cap (12) to said package (1) and thereby defining a maximum distance said cap (12) can be removed from said wall (4) in use.

14. The method of claim 13, wherein the connecting element (26, 26 ') comprises a first end portion (27, 27'), a second end portion (28, 28 ') and a connecting portion (29, 29') connecting the first end portion (27, 27 ') and the second end portion (28, 28') to each other;

the method further comprises the steps of:

v) fitting said first end (27, 27') to said cap (12); and

vi) fitting said second end (28, 28') to said package (1).

15. The method of claim 14, wherein the step vi) of assembling comprises the steps of:

vii) attaching the second end (28 ') of the connecting element (26') to the wall (4) of the package (1).

16. The method according to claim 14, wherein the opening device (3) comprises a frame (10), said frame (10) defining the passage (11) and being fittable on the wall (4) around the opening area; the cap (12) being configured to cooperate in contact with the frame (10) to close the channel (11);

and wherein step vi) of assembling comprises the steps of:

viii) attaching the second end (28) of the connecting element (26) to the frame (10).