HK1087082B - Closable opening device for packages of pourable food products - Google Patents

Description

Closable opening device for packages of pourable food products

Technical Field

The present invention relates to a closable opening device for packages of pourable food products.

Background

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

A typical example of such packages is a parallelepiped-shaped package for liquid or pourable food products, known as Tetra Brik Aseptic (registered trademark), which is manufactured by folding and sealing a web of sheet-like packaging material. The packaging material has a multilayer structure comprising a layer of fibrous material, such as paper, covered on both sides with a heat-seal plastic material, such as polyethylene; and for aseptic packages of long-storage products, such as UHT milk, the packaging material comprises a layer of oxygen-barrier material, such as aluminium foil, which is superimposed by a layer of heat-seal plastic material, and is also covered with another layer of heat-seal plastic material, so as to finally form the inner face of the package contacting the food product.

Such packages are usually made by fully automatic packaging machines, on which a continuous tube is formed from a reel-fed packaging material. The web of packaging material is sterilized on the packages, for example by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which is, after sterilization, evaporated by heating to remove the hydrogen peroxide solution on the surface of the packaging material; and the web of packaging material so sterilized is maintained in a sealed, sterile environment and is folded and sealed longitudinally to form a vertical tube.

The tube is filled with the sterilized or sterile-processed food product and is sealed and cut along equally spaced cross sections to form pillow packs, which are subsequently folded mechanically to form the finished, e.g. substantially parallelepiped-shaped, packages.

Alternatively, the packaging material is cut into blanks, which are folded over a forming mandrel to form packages, which are subsequently filled with food products and sealed. An example of this type of package is a "gable-top" package, which is known by the trade name Tetra Rex (registered trade mark).

In order to open the above packages, various solutions have been proposed, one of which known from us patents 4655387 and 4410128 comprises: forming a preferred tear line at a corner of a flap on the package, the tear line being defined by a series of perforations extending through the outer layer of the packaging material down to the layer of barrier material; and the package is opened by pulling the flap and cutting or tearing along the perforation. It goes without saying that this type of package cannot be resealed once opened and must therefore be handled with care to avoid the food product from spilling until it is used up.

In order to overcome this drawback, packages of the above type are equipped with closable opening devices, which substantially comprise: a bracket defining an opening and applied around the aperture or a removable or pierceable portion in a wall of the package; and a cover hinged to the bracket. The cover is typically integrally moulded with the carrier and has initially been sealed to the carrier along the peripheral edge around the opening by means of a weakened thin annular connecting portion. Once the seal is removed, the cover is movable between a closed position in airtight engagement with the frame and an open position. Alternatively, a threaded cap may also be used which may be separate from the bracket and which has been initially screwed onto the bracket.

One problem with opening arrangements of the type described is that the lid must be separated from the holder practically without effort when unsealing the package. The opening device is therefore made of a plastic material, typically polyethylene, having a low breaking strength.

However, polyethylene has the disadvantage of not being an effective oxygen barrier. Thus, on the side of the packaging material eventually defining the inside of the package, the opening is closed by an additional tab of heat-seal plastic material comprising a small sheet, and the opposite side of the packaging material is fitted with an oxygen barrier element, such as a pull-off tab, which is heat-sealed with the tab and has an aluminium layer.

However, providing the package with the tab and the blocking element requires additional handling of the packaging material before the package is sterilized and folded and sealed to form the vertical tube, thus prolonging the manufacture of the package and consequently being more expensive.

Moreover, once the lid is opened, the blocking element also needs to be removed in order to gain access to the contents of the package.

Therefore, closable opening devices have been proposed, by means of which the package can be opened in one operation and at the same time the oxygen barrier is ensured to be effective.

In the solution described in international patent application WO 95/05996, such opening devices substantially comprise: a holder having a cylindrical collar defining a pour opening and fitting around a pierceable portion of a package; a detachable cover screwed to the holder collar on the outside to close the opening; and a substantially tubular cutting element screwed inside the holder collar and having an end edge with a plurality of substantially triangular end teeth which engage the pierceable portion of the package so as to separate its portion, except for a small portion of its peripheral portion, from the opposite wall.

The cutting member is operable by means of a one-way ratchet-type transmission when the cap is removed from the ferrule, and rotates relative to the holder from an upper rest position, in which the end teeth face the pierceable portion, to a lower successive cutting position, in which the end teeth simultaneously interact with the pierceable portion.

A drawback of opening devices of this type is that, in use, the cut-out portion of the pierceable portion tends to at least partially obstruct the opening section of the cutting member and, consequently, the pouring opening, thereby affecting the outflow of the product from the package.

Moreover, for functional reasons, the cutting member is generally made of a material (for example polypropylene) having a structural rigidity which is higher than that of the material of the support and of the lid (generally polyethylene), which may cause the end teeth of the cutting member to be excessively fragile, possibly breaking during transport and/or when the package is unsealed, and thus to spill the food product.

These problems have been solved by the solution described in EP- ｃA-1088765, wherein the end edge of the cutting member comprises ｃA single cutting edge acting along the main peripheral portion of the pierceable portion of the package.

In addition to the cutting, a single cutting edge, which moves rotationally and acts along the main peripheral portion of the pierceable portion of the package, also exerts a thrust on the cut portion of the pierceable portion and tends to bend inside and outside the cutting member and eventually surround it, thus preventing the cut portion of the pierceable portion from interfering with the outflow of the articles from the package.

Moreover, the use of a single cutting edge of suitable configuration makes it possible to obtain a high efficiency of the cutting member, which can therefore be made of a less rigid material, for example the same material as the cover and the support, and can advantageously be moulded integrally with the support.

Although the above solution is advantageous for use in most applications, it is limited with respect to the material from which the pierceable portion of the package is made. That is, when the pierceable portion is made of a particularly rigid material, such as a barrier material covered by a metallo-organic compound or a metallocene-catalyzed polymer, the latter tends to "stretch" rather than tear under the action of the cutting edge, thus forming a helical residue on the cutting edge, which may be incorporated into the food product.

Disclosure of Invention

The aim of the present invention is to provide a closable opening device designed to eliminate the above-mentioned typical drawbacks related to known devices, in particular when the pierceable portion is made of a particularly rigid material, avoiding the formation of a helical residue in the pierceable portion that may enter the food product.

According to the present invention, an opening device is provided. In particular a closable opening device for sealed packages of pourable food products, comprising:

a bracket secured around the pierceable portion of the package and defining a through-hole;

a removable threaded cap screwed onto the bracket to close the aperture;

a tubular cutting member engaged with the aperture and having an end cutting edge cooperating with the pierceable portion to unseal the package;

first connecting means for connecting the lid to the cutting member so as to rotate the cutting member during rotation of the lid to screw the lid off the holder when unsealing the package; and

second connecting means for connecting the holder to the cutting member to move the cutting member through the pierceable portion along a helical path in response to said rotation of the cap;

the cutting edge comprises a primary blade;

characterized in that the cutting edge comprises at least a first plurality of teeth arranged along the cutting edge in a direction opposite to the direction of rotation of the cutting member so as to be downstream of the main blade; the height of said first plurality of teeth is gradually reduced so as to act on the pierceable portion one by one.

Furthermore, the main blade has a cutting side facing the direction of travel of the cutting member relative to the pierceable portion and inclined rearwardly. The height of the first tooth decreases linearly with respect to the height of the main blade. The first tooth has a respective end disposed along a line having a slope less than the helical path of the cutting member. One of the first teeth adjacent to the main blade has the same height as the main blade.

The cutting edge of the cutting member includes a plurality of second teeth located on an opposite side of the first teeth relative to the main blade. The second teeth all have the same height and are at most equal to the minimum height of the first teeth.

The cutting edge of the cutting member comprises a secondary blade having a width of 3-7 times one of said first or second teeth. The secondary blade has a cutting side facing the direction of travel of the cutting member and having the same slope as the side of the first or second tooth.

The holder includes a cylindrical collar to receive the cap and to define the bore; and the second connecting means comprise an internal thread of the ferrule and an external thread of the cutting element.

The holder and the cutting element are moulded in one piece in a pre-assembled configuration, in which they are coaxially connected to each other by means of connecting means.

Drawings

Preferred but non-limiting embodiments of the present invention are described below 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 for pourable food products, provided with a closable opening device according to the present invention;

fig. 2 is a partially exploded view of the opening device shown in perspective in fig. 1 in a state of use;

fig. 3 is a detailed side view of the opening arrangement shown in fig. 1 in a pre-assembled state before assembly to a package;

fig. 4 is a side view of the cutting member of the opening device shown in fig. 1, positioned facing the pierceable portion of the package;

FIG. 5 is a plan view of the cutting element shown in FIG. 4;

FIG. 6 is an expanded plan view of the cutting element shown in FIG. 4; and

fig. 7 is an enlarged view of a detail in fig. 6.

Detailed Description

Number 1 in fig. 1 indicates as a whole an Aseptic sealed package for pourable food products, for example a parallelepiped-shaped package known as Tetra Brik Aseptic (registered trademark), made of a sheet 2 of packaging material and having a top wall 3 to which a closable opening device 4 made of plastic material is applied by means of a conventional fixing system, for example adhesive or micro-flame or laser heat-sealing techniques.

The packaging material 2 (fig. 4) has a multilayer structure comprising: for example, paper material layer 5; an outer layer 6 of thermoplastic material, for example polyethylene; and a plurality of inner cover layers, hereinafter collectively referred to as "inner cover portions 7". For aseptic packages for long-storage products, such as fruit juices, UHT (ultra-high-temperature treated) milk and the like, the inner covering portion 7 usually comprises an intermediate barrier, such as aluminium, which is in turn covered by one or more layers of thermoplastic material. The inner layer of thermoplastic material which in use contacts the article is preferably defined by a Low Linear Density (LLD) polyethylene which is metallocene catalysed and has good mechanical strength and in particular a high tensile modulus.

The wall 3 has a pierceable portion 10 which, in use, is covered on the outside by the opening device 4 and which is at least partially separable from the wall 3 so as to allow the food product to flow out of the package 1.

The pierceable portion 10 is preferably defined by a so-called "prelaminated hole", i.e. a hole 11 formed through the paper material layer 5 before the outer layer 6 and the inner cover portion 7 are laminated, so that the outer layer 6 and the inner cover portion 7 adhere to each other inside the hole 11 and define the pierceable portion 10 (see fig. 4).

Referring to fig. 2 and 3, opening device 4 includes: a support 15, which is fixed to package 1 around pierceable portion 10 and has a circular through hole 16 of axis a, through which the food product can be poured; a cover 17 coaxially fitted to the bracket 15 so as to close the opening 16; and ｃA tubular cutting member 18 of axis ｃA, which in use is engaged in axially and angularly movable manner with hole 16 and can be actuated by lid 17 as described in EP- ｃA-1088765, EP- ｃA-1088765 being incorporated herein by reference, so as to interact with pierceable portion 10 of wall 3 and unsealing package 1.

The support 15 comprises an annular base flange 19 fixed to the wall 3 of the package 1 around the pierceable portion 10, and from whose radially inner edge a cylindrical collar 20 of axis a axially projects so as to define the hole 16.

The collar 20 has an external thread 23 and an internal thread 24 (see figure 4) which, in use, have a relative inclination and engage respectively an internal thread 25 of the cap 17 and an external thread 26 of the cutting element 18.

Suitably, the thread 23 is a conventional right-hand thread; and thread 24 is a left-hand, multi-start thread having a pitch greater than that of thread 23.

The cover 17 includes: a circular end wall 27; and a generally cylindrical side wall 28 having internal threads 25 and an external protrusion 29 to facilitate gripping.

The lid 17 and the stand 15 are suitably provided with tamper-detecting means, not shown, which are known and not part of the present invention, for securing the lid 17 and the stand 15 in ｃA position for sealing the package 1, an example of which is described in the above-mentioned EP- ｃA-1088765.

The cutting element 18 is suitably injection moulded in one piece with the carrier in a pre-assembled position as shown in fig. 3, in which one axial end of the cutting element 18 is temporarily connected to the flange 19 of the carrier 15 by means of a plurality of breakable radial bridges 30 surrounding the hole 16. The cutting member 18 is in use screwed into the collar 20 of the support 15 and is suitably driven axially into the collar 20 before the support 15 is fitted to the package 1.

The cutting member 18 (see fig. 5) has two or more internal axial ribs 32 designed to cooperate with respective transmission members 33 projecting axially from the end wall 27 of the cover 17 and schematically represented by broken lines in fig. 5. The ribs 32 and the transmission element 33 define ｃA one-way transmission, not described in detail here, known from EP- ｃA-1088765, by means of which the cover 17 is connected rotationally to the cutting element 18 in the direction of cover unscrewing shown in fig. 5, but not in the opposite direction.

The cover 17 may suitably also be driven axially onto the collar 20 when assembling the opening device 4.

At the opposite axial end, cutting member 18 comprises a cutting edge 31 designed to interact with pierceable portion 10 of package 1 (see fig. 4).

According to the invention, the cutting edge 31 comprises, in succession along its periphery, a main blade 36 and a plurality of teeth 37, as clearly shown in the developed plan view of the cutting member 18 of fig. 6, an enlarged view of the profile of the cutting edge 31 being shown in fig. 7.

The main blade 36 is asymmetrically triangular in shape, including a rearwardly sloping cutting side 38 facing the cutting direction, and an opposite side 39 which is slightly inclined to the slope of the thread 26, the slope of the thread 26 being indicated by line E in fig. 7. The teeth, designated as a whole by the reference numeral 37, can be divided into a first group 37a and a second group 37 b.

The teeth 37a are arranged along the cutting edge 31 in a direction opposite to the direction of rotation of the cutting member 18, each tooth 37a having a substantially triangular profile, immediately behind the main blade 36, with a symmetrical hypotenuse 40, and progressively decreasing in height with respect to a base line B of the profile of the cutting edge 31. More specifically, the first tooth 37a adjacent to the main blade 36 is preferably of the same height as the main blade 36, and the height of the following teeth 37a decreases linearly so that the teeth 37a come into contact with the pierceable portion 10 one by one. The slope of line L passing through the apex of tooth 37a is suitably less than the slope of the thread so that tooth 37a contacts pierceable portion 10 at separate and spaced points.

The teeth 37B are located on the opposite side of the tooth 37a with respect to the main blade 36, i.e. behind the tooth 37a in the direction of rotation of the cutting member 18, each tooth 37B having a substantially triangular profile with a symmetrical hypotenuse 41 and a constant height with respect to a base line B of the profile of the cutting edge 31, suitably the same as the height of the last tooth 37a, which can also be considered as the first tooth 37B.

The cutting edge 31 further comprises a secondary blade 42 having a greater circumference than the teeth 37, preferably 3-7 times the width of each tooth, more preferably even 5 times the width of each tooth 37, and the secondary blade 42 is defined by a cutting edge 44 and a guiding edge 45, the cutting edge 44 facing the direction of travel of the cutting edge 31 relative to the pierceable portion 10 and having substantially the same slope as the sides of the teeth 37, the slope of the guiding edge 45 being substantially less steep and preferably having the same slope as the sides 39 of the primary blade 36.

The cutting edge 31 includes three flat regions 46 axially set back relative to the teeth 37 and blades 42, 36, which are circumferentially spaced along the cutting edge 31. The region 46 which lies along or close to the base line B has no cutting function and serves as a thrust surface for a tool (not shown) by means of which the cutting member 18 can be driven into the collar 20 in the pre-assembly position.

The operation of opening device 4 in the sealing position shown in fig. 1 and 2 will be described below, (in fig. 2, cover 17 is shown separated for the sake of simplicity), in which cutting member 18 is fully housed within collar 20, with cutting edge 31 facing pierceable portion 10 (see fig. 4) which has not been cut open.

When selected in the opening direction (anticlockwise in fig. 5), the cover 17 causes the cutting member 18 to rotate, possibly after idling to disengage the tamper-detecting device, by means of the transmission member 33 engaging the rib 32.

Given the opposite slope of threads 24 and 26, when cap 17 is unscrewed, cutting member 18 moves axially downward to interact with pierceable portion 10.

To clearly understand the way in which the cutting edge 31 interacts with the pierceable portion 10, it should be pointed out that, as shown in fig. 7, the cutting edge 31 moves along a helical path that, when flattened, is equivalent to a translation along a direction T that forms an angle with the plane of the pierceable portion 10 that is equal to the pitch of the thread 26 and therefore parallel to the line E.

First, the main blade 36 and the first tooth 37a come into action simultaneously with each other. And once the material is pierced by the main blade 36, the "hook" -shaped main blade 36 "hooks" and circumferentially pulls it, so as to prevent any appreciable movement of the material under the action of the axial component of the thrust exerted by the travel of the cutting member 18, and thus prevents the material from disengaging the action of the teeth 37 a.

The teeth 37a act one by one and in rapid succession so as to simulate the perforating action obtained by the vertical movement. The teeth 37a pierce the material and each cut through the portion of material between its own point of contact and the cut made by the preceding tooth 37a, so that the cut is not entirely made by the main blade 36 and the horizontal stretch of the material is reduced.

The teeth 37b and the secondary blade 42 act substantially simultaneously and, when the cutting member is rotated, first pierce the material and then make a continuous cut.

The cutting action of the cutting member is terminated after one rotation of cutting member 18 at the location of first contacting pierceable portion 10, which is sufficient for the cutting member to cut axially downwardly through pierceable portion 10 to baseline B, and corresponds to a cut of approximately 270 degrees. The portion of the pierceable portion that remains uncut and prevents it from completely separating is the portion between the maximum cut-through point of primary blade 36 and the initial piercing point of secondary blade 42. Further rotation of the cutting member 18 causes the portion to bend axially outwards of the cutting member 18 and not cut, as schematically shown in broken lines in fig. 4, so that the pierceable portion 10 moves away from the hole 16 in the holder 15 and does not interfere with the outflow of the food product from the package 1.

When the cover 17 is unscrewed further while making substantially a full turn about the axis a, the ribs 32 and the transmission member 33 are disengaged axially, so that the cutting member 18 stops in the lower opening position, projecting axially from the support 15 into the package 1, but remains connected to the collar 20 by means of the engagement of the threads 24 and 26.

The lid 17 can be unscrewed completely to open the package 1, which can be closed by simply screwing the lid 17 back onto the collar 20.

Once the package is unsealed, the cutting member 18 is no longer moved from the lower opening position, the axial position of engagement with the rib 32 of the cutting member 18 cannot be reached by the transmission member 33, so that the cutting member 18 keeps the cut portion of the pierceable portion 10 clear of the aperture 16.

Experiments have shown that the cutting member 18 according to the invention allows the pierceable portion 10 of the package 1 to be free of any helical residue, even when using an inner covering of thermoplastic material with a high tensile modulus, and also allows the pierceable portion 10 to be correctly bent outwards of the cutting member 18.

It is clear that changes and modifications can be made to opening device 4 described and illustrated without departing from the scope of the appended claims.

Claims (11)

1. A closable opening device (4) for a sealed package (1) of a pourable food product, the device (4) comprising:

a bracket (15) fixed around the pierceable portion (10) of the package (1) and defining a through hole (16);

a removable threaded cap (17) screwed onto the support (15) so as to close the hole (16);

a tubular cutting member (18) engaged with the aperture (16) and having an end cutting edge (31) cooperating with the pierceable portion (10) to unseal the package (1);

first connecting means (32, 33) for connecting the lid (17) with the cutting member (18) so as to rotate the cutting member (18) during rotation of the lid (17) for screwing the lid (17) off the holder (15) when unsealing the package (1); and

second connection means (24, 26) for connecting the support (15) with the cutting member (18) so as to move the cutting member (18) along a helical path through the pierceable portion (10) in response to said rotation of the cap (17);

the cutting edge (31) comprises a main blade (36);

characterized in that the cutting edge (31) comprises at least a first plurality of teeth (37a), said first plurality of teeth (37a) being arranged along the cutting edge (31) in a direction opposite to the direction of rotation of the cutting member (18) so as to be downstream of the main blade (36); the height of said first plurality of teeth is gradually reduced so as to act on the pierceable portion (10) one by one.

2. A device as claimed in claim 1, characterized in that the main blade (36) has a cutting side (38) facing the direction of travel of the cutting member (18) relative to the pierceable portion (10) and inclined rearwardly.

3. The device according to claim 1 or 2, characterized in that the height of the first tooth (37a) decreases linearly with respect to the height of the main blade (36).

4. A device as claimed in claim 3, wherein the first tooth (37a) has respective ends arranged along a line (L) having a slope smaller than the helical path (T) of the cutting member (18).

5. The device according to claim 3, wherein one of the first teeth (37a) adjacent to the main blade (36) has the same height as the main blade (36).

6. The device according to claim 1, characterized in that the cutting edge (31) of the cutting member (18) comprises a plurality of second teeth (37b) located on the opposite side of the first teeth (37a) with respect to the main blade (36).

7. Device according to claim 6, characterized in that said second teeth (37b) all have the same height and are at most equal to the minimum height of the first teeth (37 a).

8. Device according to claim 6 or 7, characterized in that the cutting edge (31) of the cutting member (18) comprises a secondary blade (42) having a width of 3-7 times one of said first or second teeth (37a, 37 b).

9. Device according to claim 8, characterized in that the secondary blade (42) has a cutting side (44) facing the direction of travel of the cutting member and having the same inclination as the side of said first or second tooth (37a, 37 b).

10. The device according to claim 1 or 2, characterized in that the holder (15) comprises a cylindrical collar (20) to receive the cover (17) and to define the hole (16); and the second connecting means comprise an internal thread (24) of the ferrule (20) and an external thread (26) of the cutting element (18).

11. Device according to claim 1 or 2, characterized in that the holder (15) and the cutting member (18) are moulded in one piece in a pre-assembled configuration, in which they are coaxially connected to each other by means of connecting means (30).