HK1036960B - Closable opening device for sealed packages of pourable food products - Google Patents

Description

Closable opening device for sealed packages of pourable food products

Technical Field

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

Background

As is known, many pourable food products, such as fruit juice, ultra-high temperature treated milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.

A common example of such a package is a parallelepiped-shaped package for liquid or pourable food products, such as the known Tetra Brik Aseptic (registered trademark), which is formed by folding and sealing a laminated web packaging material. The packaging material has a laminate structure comprising a layer of fibrous material, such as paper, which is covered on both sides with a layer of, for example, polyethylene, heat-seal plastic material, and, in the case of aseptic packages for long-storage products, such as uht milk, it also comprises a layer of oxygen-barrier material, for example, formed by an aluminium film, which is superimposed on the layer of heat-seal plastic material and in turn is covered with another layer of heat-seal plastic material eventually forming the inner surface of the package contacting the food product.

Such packages are typically made on fully automatic packaging machines. On a packaging machine, a continuous tube is formed from a supply of band-shaped packaging material; the web of packaging material is sterilized on the packaging machine, for example by supplying a chemical sterilizing agent, such as a hydrogen peroxide solution, which is removed from the surface of the packaging material after sterilization, for example by evaporation by heating; the thus sterilized packaging material web is kept in a closed sterile environment and is folded and sealed in the longitudinal direction to form a vertical tube.

The tube is filled with the sterilized or sterile-processed food product and is sealed and cut at equally spaced cross sections to form pillow assemblies, which are then mechanically folded to form, for example, a generally parallelepiped-shaped, finished package.

In addition, the packaging material is cut into blanks, which are formed into packages on forming spindles, and the finished packages are filled with the food product and sealed. An example of such a package is the so-called gable-top package, generally known under the trademark Tetra Rex (registered trademark).

Various proposals have been made for opening the package, one of which is described in us patent nos. 4,655,387 and 4,410,128, which involve forming preferential tear lines in the corners of the lid of the package, the tear lines being formed by continuous perforations extending down through the outer layer of the packaging material to the layer of barrier material; the package is opened by lifting the lid and cutting or tearing along the perforations. Obviously, such packages cannot be closed once opened and, therefore, must be handled with care to prevent spillage of the remaining food product within the package.

To solve this problem, packages of the above-mentioned type are provided with closable opening devices which generally comprise a seat which defines an aperture and is fitted over the aperture or over a portion of the wall of the package which is engaged or torn, and a lid which is hinged to the seat. The cap is typically integrally moulded with the seat and is initially sealed to the seat along a circumferential edge around the opening by a thin breakable annular connection. Once opened, the lid is moved between a closed position in fluid-tight engagement with the seat and an open position. In addition, a threaded cap is used which is separate from the seat and is initially screwed onto the seat.

One problem with such opening devices is that it is practical to ensure that the lid does not have to be laboriously detached from the seat when opening the package. For this purpose, the opening device is made of a plastic material with low tear strength, typically polyethylene.

However, since polyethylene does not act as an effective oxygen barrier material, the side of the packaging material eventually defining the interior of the package must be provided with an additional sheet member formed from a small piece of heat-seal plastic material over the aperture. The opposite side of the packaging material must be provided with an oxygen barrier, for example a tear-off tab, which is heat-sealed to the sheet member and which has a thin layer of aluminium.

Providing a package with spacers and foil members requires additional handling of the packaging material before sterilization and folding and sealing into a vertical tube, thus increasing the production time and cost of the package.

In addition, after opening the lid, the user must also remove the spacer to open the package.

Therefore, closable opening devices have been designed which allow the package to be opened in one operation while obtaining an effective oxygen barrier.

According to international patent application WO 95/05996, such opening device comprises a seat having a cylindrical sleeve defining a pouring opening and fixed to an engagement portion of the packaging, a removable cap screwed onto the outside of the sleeve of the seat to close the pouring opening, and a substantially tubular cutting member; the tubular cutting member is screwed inside the sleeve of the seat and has an end edge with a number of substantially triangular end teeth which interact with and partially separate the package engaging portion from the relevant wall, for example, except for a small angular range.

The cutting member is actuated by the cap by means of a one-way ratchet transmission, which operates when the cap is disengaged from the sleeve, the cap moving along a helical path with respect to the seat from a raised rest position, in which the end teeth face the engagement portions, to a sequentially lowered cutting position, in which the end teeth interact with the engagement portions.

A drawback of opening devices of the above type is that they require the stocking and assembly of three separate pieces (seat, cover, cutter), and even more, they have to be made using three different moulds, thus resulting in high costs.

Disclosure of Invention

The object of the present invention is to provide a closable opening device for sealed packages of pourable food products, designed to eliminate the above-mentioned drawbacks typically associated with known opening devices.

According to the present invention, there is provided a closable opening device for a sealed package containing a pourable food product, said opening device comprising:

-a seat defining a through hole and fixed around the engagement portion of said package;

-a removable cover cooperating with said seat to close said hole; and

-a substantially tubular cutting member which, in use, cooperates with said aperture in an angularly and axially movable manner and has end edges which, at their end faces, have cutting means which interact with said engagement portions to open said package;

characterised in that said seat and said cutting member are moulded as a single piece of pre-assembled construction, in which they are mutually coaxially fixed by breakable connecting means; and

said breakable connection means comprise a plurality of connecting bridges extending radially between the other end edge of said cutting member opposite said end edge and a surface by which said seat is fixed to said package; the connecting bridge is broken when the cutting member engages the aperture.

Drawings

With reference to the accompanying drawings, there will be illustrated a preferred, non-limiting embodiment of the present invention; wherein:

fig. 1 shows a perspective view of the upper part of a sealed package of a pourable food product, having a closable opening device according to the invention;

figures 2 and 3 show enlarged cross-sectional views of two embodiments of materials representing the package of figure 1 showing the combined layers;

FIG. 4 shows an enlarged exploded side view of the device of FIG. 1 prior to being loaded onto a package;

FIG. 5 shows an enlarged exploded axial cross-sectional view of the device of FIG. 1 prior to attachment to a package;

FIG. 6 shows an enlarged axial cross-sectional view of the device of FIG. 1 sealingly attached to a package;

FIG. 7 shows a cross-sectional view taken along line VII-VII of FIG. 6;

FIG. 8 shows an enlarged axial cross-sectional view of the device of FIG. 1 with the package open;

FIGS. 9-11 show views of the device of FIG. 1 in sequential states with the package open, as viewed from the interior of the package;

FIG. 12 shows an enlarged bottom perspective view of the cover of the device of FIG. 1;

FIG. 13 shows an enlarged side view of the cutting member of the device of FIG. 1;

fig. 14 shows an enlarged side view of a detail of the cutting element of fig. 13.

Detailed Description

Fig. 1 shows a wholly sterile sealed package of pourable food products, for example a parallelepiped-shaped package known as tetra brik aseptic (registered trademark), made from the above-mentioned packaging sheet material and comprising closable opening devices 2 made of plastic material and fixed to package 1 in a conventional manner, for example by means of adhesive or using micro-flame or laser sealing techniques.

The packaging material (fig. 2 and 3) has a multilayer structure and, at the circular join 4 of the upper wall 3 of the package 1 with respect to the axis a, is, in use, externally covered by the opening device 2 and at least partially detached from the upper wall 3 in order to pour the product from the package 1.

In the case of non-aseptic packages for pasteurized products (e.g. yoghurt, cheese and other products of the frozen range), the packaging material comprises a layer 5 of fibrous material, usually paper, which is covered on the outside and inside by respective layers 6, 7 of thermoplastic material, such as polyethylene (figure 2); the joints 4 are defined by preferential tear lines 8 and sequential perforations formed in the layer of fibrous material 5.

In the case of aseptic packages for long-storage products, such as ultrathermally treated milk, the packaging material also comprises, on the side eventually contacting the food product of the package 1, for example, on the layer 7 of thermoplastic material, a layer 9 of barrier material, such as aluminium, the layer 9 of barrier material being in turn covered by one or more layers 10 (figure 3) of thermoplastic material; the joint 4 is defined by the layers 6, 7, 10 of thermoplastic material and by the layer 9 of insulating material covering the hole 11, the hole 11 being formed in the layer 5 of fibrous material with respect to the axis a.

With reference to fig. 4-8, opening device 2 comprises a seat 15 defining a through hole 16 about axis a, through hole 16 a food product is poured; seat 15 is fixed around joint 4 on wall 3 of package 1; the cover 17 is formed separately from the seat 15; a tubular cutting member 18 about axis a engages hole 16 in an axial and angular movement, which is acted upon by a cover 17 to interact with engaging portion 4 of wall 3 to open package 1.

Seat 15 comprises an annular flange 19, end face 19a of flange 19 being fixed around joint 4 on wall 3 of package 1; and a cylindrical sleeve 20 extends axially from the radially inner edge of the flange about axis a, sleeve 20 defining bore 16.

The respective opposite sides 21, 22 of the sleeve 20 comprise an external thread 23 and an internal thread 24, which are inclined in opposite directions with respect to the axis a and which, in use, engage respectively a thread 25 of the cap 17 and a thread 26 of the cutting element 18. The thread 23 extends along a majority of the surface 21, except for the bottom cylindrical band adjacent the surface 21 of the flange 19; likewise, the thread 24 extends along a substantial portion of the surface 22, except for the upper cylindrical band of the surface 22 near the end edge 27 of the sleeve 20 at the opposite end of the dividing flange 19.

The sleeve 20 also comprises an annular flange 28 on the surface 21, which is axially interposed between one end of the thread 23 and the flange 19, and is positioned at a fixed axial distance from the flange 19.

With reference to figures 4-8 and 12, the cap 17 comprises a hollow cylindrical body defined by a circular end wall 29 for closing the hole 16 and a cylindrical side wall 30 projecting from the circumferential edge of the end wall 29, the cap comprising an internal thread 25 which can be screwed onto the sleeve 20 of the seat 15.

The end wall 29 comprises a projecting annular flange 35 adjacent to the side wall 30 and defining, with the side wall 30, an abutment 36 for receiving the end edge 27 of the sleeve 20.

The cover 17 is integrally moulded in a conventional manner with a respective tamper-evident ring 37, the tamper-evident ring 37 being coaxially connected at the opposite end to the end edge 38 of the cover 17 by a plurality of breakable radial connection points.

The cap 17 is initially fitted onto the sleeve 15 and is in the closed position, in which it is completely screwed onto the sleeve 20, the end edge 38 of the cap and the tamper-evident ring 37 still being connected to each other and abutting against the opposite side of the flange 28 of the sleeve 20. In the closed position, the tamper-evident ring 37 clicks between the flange 19 and the flange 28, the abutment 36 of the lid 17 coming into contact with the end edge 27 of the sleeve 20.

Once opened, the cap 17 moves between an open position, in which it is unscrewed from the sleeve 20 and detached from the seat 15, and a closed position, in which it closes the hole 16.

With reference to fig. 4-8, 13 and 14, the cutting member 18 has a thread 26 on the outer surface 29, by means of which thread 26 the cutting member 18 is engaged with the thread 24, is attached inside the sleeve 20 of the seat 15, and has an end edge 40, which end edge 40 has cutting means 41 on its end face, which interact with the abutment 4 to open the package 1.

When package 1 is first opened, threads 24 and 26 define a helical path about axis a, along which cutting member 18 is fed through junction 4 from a raised rest position (fig. 6 and 9) to a lowered open position (fig. 8 and 11). In the raised rest position, the cutting member 18 is completely housed inside the sleeve 20, the cutting means 41 facing the engaging portion 4 of the pack 1; in the lowered open position, the cutting member 18 projects axially with respect to the sleeve 20 and penetrates the package 1 for a predetermined distance and completes the cutting of the joint 4, while the joint is kept connected to the wall 3 by the small angled portion 42.

The cutting element 18 comprises a plurality of stop lugs 44 projecting radially from the surface 39 at the end edge 40. In case lid 17 is turned in the wrong way when opening package 1, for example in the direction of screwing lid 17 onto seat 15, projection 44 will abut against the end of thread 24 of sleeve 20 near flange 19 to prevent axial displacement of cutting member 18 beyond the raised rest position and possible damage to end wall 29 of lid 17.

The displacement of the cutting member 18 from the raised position to the lowered position is controlled by the cover 17 via a one-way angular actuator 45 (figures 5-8, 12), which is selectively deactivated once the cutting member 18 reaches the lowered open position.

The transmission means 45 comprise a plurality of first teeth 46, four in the embodiment shown, the first teeth 46 having a saw-tooth profile, which protrudes from the end wall 29 of the cover 17 and is angularly equally spaced about the axis a in the closed position and in the open position of the cover 17; the transmission means 45 comprise a plurality of second teeth 47, eight in the embodiment shown, the second teeth 47 also having a saw-tooth profile, which projects radially from the inner surface 48 of the cutting member 18 and which, when the package 1 is first opened, during disengagement of the cover 17 from the sleeve 20, the second teeth 47 engage in an axially free, angularly integral manner with the teeth 46. Fig. 1 shows the cap 17 disengaged by rotation of the cap 17 in a counter-clockwise direction about axis a.

Each tooth 46 comprises a connecting portion 49 projecting perpendicularly from the end wall 29 of the cover 17 and an engaging portion 50 projecting from the connecting portion 49 towards the side wall 30 and having an obtuse triangular cross-section. The engagement portion 50 is defined by two inclined outwardly converging sides 51, 52; the flank 51, which is more steeply inclined with respect to the connecting portion 49, defines an abutment for the corresponding tooth 47 in the direction of rotation R of the cover 17; the other side 52 allows the teeth 4 to slide angularly in the opposite direction.

Each tooth 47 extends the entire axial height of the cutting member 18 and has an obtuse triangular cross-section identical to the meshing portion 50 of the tooth 46, which is defined by two inclined converging sides 53, 54; the side 53 is more steeply inclined with respect to the surface 48 of the cutting member 18 and faces the side 51 of the respective tooth 46.

In a preferred embodiment, the cutting means 41 comprise a single cutter 55, the single cutter 55 cutting along a circumferential portion C (substantially three quarters in the embodiment shown) of the joint 4 when the cutting member 18 is moved with respect to the seat 15, so as to only partially separate the joint 4 from the wall 3, for example almost the portion 42.

With particular reference to fig. 4, the cutter 55 is defined by a tooth formed on the end edge 40 of the cutting member 18, which has a substantially triangular profile defined by a cutting edge 56 and a side cutting edge 57 crosswise to the junction 4 of the wall 3; the side cutting edge 57 has a curved profile inclined with respect to the axis a and it joins the free end of the cutting edge 56 of the end edge 40.

The cutter 55 comprises a cutting portion 58, the cutting portion 58 projecting axially with respect to the end edge 40, which is formed towards the inside of the cutting member 18 by a surface 59 slightly inclined with respect to the joint 4, so as to define a section of the cutting portion 58, which tapers towards the joint 4.

Adjacent to the cutters 55, the end edge 40 of the cutting element 18 has a ramp-shaped recess 60, the ramp-shaped recess 60 increasing in depth towards the cutters 55 and defining an axial height of the cutting edge 56 which is greater than the axial height of the cutting portion 58.

According to an important feature of the invention, the seat 15 and the cutter 18 are moulded in a single piece and are coaxially interconnected in a pre-assembled configuration (fig. 4 and 5) by a number of breakable radial connecting bridges 62, while the cutter 18 protrudes axially and completely with respect to the end of the flange 19 in the pre-assembled configuration. In this pre-assembled configuration, the cutting element 18 is axially aligned with the flange 19 at an end edge 63 of the cutting element opposite the end edge 40 and is connected to the inner edge of the surface 19a of the flange 19 by a connecting bridge 62.

Opening device 2 is assembled by inserting cutting member 18 into sleeve 20, thus disconnecting bridge 62, and simultaneously or subsequently fitting cover 17 onto seat 15, before opening device 2 is fixed to joint 4 of package 1.

During insertion of the cutting element 18 into the sleeve 20, the threads 24 and 26 cooperate with each other, the teeth 47 sliding axially on both of the opposite angled sides of the respective tooth 46 engaging portion 50.

After the cap 17 has first been brought into a predetermined angular position relative to the cutting member 18, the cap 17 is preferably fitted onto the seat 15 by applying axial pressure so that the threads 23 and 25 engage each other and the tamper-proof ring 37 clicks over the annular flange 28 of the sleeve 20 on the flange 19.

Alternatively, it is possible to use the movement of unscrewing of the lid 17 when opening the package by first applying an axial pressure and then screwing the lid 17 onto the sleeve 20 of the seat 15 and into the final angular position.

At the end of the above-mentioned operations, cutting member 8 is in a raised rest position inside sleeve 20 and, together with cover 17 closing aperture 16, forms a sealing structure that secures opening device 2 to package 1 (fig. 6).

In actual use, with the above-described sealing arrangement, rotating the cap package 17 in the direction R to release the cap from the sleeve 20, rotating the cap 17 relative to the axis a does not allow the package to be opened.

When cap 17 is rotated about axis a in direction R, engaged threads 23 and 25 simultaneously axially separate cap 17 from wall 3, so as to break the radial point of connection of the cap to tamper-proof ring 37, tamper-proof ring 37 remaining axially abutting against flange 28 of sleeve 20.

Upon initial rotation of the cover 17, the tooth 46 is positioned with the side 51 abutting against the side 53 of the corresponding tooth 47 of the cutting member 18, so that the cutting member 18 rotates about the axis a in the direction R.

The axial movement of the lid 17 away from the wall 3 of the package 1 is accompanied at the same time by an axial movement of the cutting member 18 towards the wall 3, by means of the engaging threads 23, 25 and 24, 26 being inclined in opposite directions. The cutting member 18 is rotated by the cap 17 and the teeth 46 and 47, the teeth 46 and 47 being in contact with the respective flanks 51 and 53, the teeth 46 and 47 simultaneously sliding axially with respect to each other due to the helical movement imparted to the cap 17 and to the cutting member 18 by the respective pairs of threads 23, 25 and 24, 26.

Initial rotation of cap 17 about axis a in direction R causes cutting member 118 to likewise rotate, causing cutting portion 58 (fig. 9) of cutter 55 to axially penetrate joint 4.

As the cap 17 is further rotated, the cutting edge 56 of the cutter 55 is angularly advanced along the circumference of the joint 4 to separate the joint from the wall 3. As the cutter 55 is angularly fed, the cutter 55 also axially penetrates, whereby a portion of the joint 4 gradually separated from the wall 3 is folded close to the cutting edge 56, and this portion is gradually folded toward the inside of the package toward a portion of the joint 4 not separated from the wall 3, as shown in fig. 10. The inclination of the surface defining the cut 58 inwardly of the cutter 18 further facilitates such folding of the section.

In this process, the axial penetration of the cutter 55 with respect to the joint 4 is greater than the axial height of the cutting portion 58 of the cutter 55, by means of the groove 60.

Once package 1 is penetrated axially by cutting knife 55 to such an extent that engaging portion 4 contacts the bottom of groove 60, when cutting knife 55 reaches the end of circumferential portion C of engaging portion 4, in the example shown, corresponding to an angular displacement of about 270 ° about axis a, further rotation of cutting knife 55 about axis a only acts to fold the remaining portion of engaging portion 4 still connected to wall 3 towards the outside of cutting member 18 without cutting it (fig. 11).

In addition, the cap 17 is unscrewed, -at this point, the cap 17 is rotated substantially one turn about the axis a-its axial release teeth 46 and 47 (fig. 8), so that the cutting member 18 is blocked in the lowered open position, which protrudes axially from the seat 15 and is still fixed to the sleeve 20 by the cooperating threads 24 and 26.

The lid 17 is then unscrewed completely to open the package 1, which can be closed by simply putting the lid 17 back on the sleeve 20.

Once the package is opened, the cutting member 18 is no longer moved from the lowered open position, the cut portion of the engaging portion 4 being kept outside the cutting member 18, and therefore the aperture 16 being kept clear, since the teeth 46 of the cover 17 cannot reach the axial position of engagement with the teeth 47 of the cutting member 18.

The advantages of the opening device 2 according to the invention are evident from the above description.

In particular, the moulding seat 15 and the cutting member 18 are a single and definitive (pre-assembled) structural device, which involves only two separate bodies, from the manufacture to the final assembly of the opening device, and which, moreover, can be assembled extremely quickly, conveniently and accurately. From the outset, the seat 15 and the cutting member 18 are moulded in a configuration that takes into account the relative angular positions of the respective threads 24 and 26, of the teeth 47 of the cutting member 18 and of the teeth 46 of the cover 17, so that preliminary operations, or equipment, are necessary in order to position the components of the opening device 2.

In addition, the seat 15 and the cutting member 18 are formed using one mold, thereby reducing the cost as compared with the known opening device.

Clearly, changes may be made to the opening device as described above without, however, departing from the scope of the accompanying claims.

Claims (6)

1. A closable opening device (2) for a sealed package (1) containing a pourable food product, said opening device comprising:

-a seat (15) defining a through hole (16) and fixed around the joint (4) of said package (1);

-a removable cover (17) cooperating with said seat (15) to close said hole (16); and

-a substantially tubular cutting member (18) which, in use, cooperates in an angular and axially movable manner with said hole (16) and has an end edge (40), which end edge (40) has, at its end face, cutting means (41) which interact with said engagement portion (4) to open said package (1);

characterized in that said seat (15) and said cutting member (18) are moulded in a single piece of pre-assembled construction, in which they are mutually coaxially fixed by breakable connection means (62); and

said breakable connection means comprise a plurality of connecting bridges (62), a connecting bridge (62) extending radially between the other end edge (63) of said cutting member (18) opposite said end edge (40) and a surface (19a) by which said seat (15) is fixed to said package (1); the connecting bridge (62) is broken when the cutting member (18) engages the aperture (16).

2. Device according to claim 1, characterized in that said connecting bridges (62) extend from the side edges of said holes (16).

3. Device according to claim 1 or 2, characterized in that said seat (15) comprises a cylindrical sleeve (20) defining said hole (16) and receiving said cover (17) and said cutting member (18) at opposite ends; and said sleeve (20) and said cutting member (18) include first and second threads (24, 26) on respective sides (22, 39) that cooperate with one another in use.

4. Device according to claim 3, characterized in that said sleeve (20) has a third thread (23) on a flank (21) opposite to a flank (22) provided with said first thread (24), inclined in a direction opposite to the first thread (24) and cooperating with a fourth thread (25) formed on said cap (17).

5. Device according to claim 1 or 2, characterized in that it comprises a unidirectional angular transmission (45) interposed between said cover (17) and said cutting member (18).

6. Device according to claim 5, characterized in that said transmission means (45) comprise a plurality of first teeth (47) and a plurality of second teeth (46), the teeth (47) having a substantially saw-tooth profile and projecting radially from a flank (48) of said cutting member (18), the flank (48) of said cutting member (18) being opposite to a flank (39) provided with said second thread (26); the second tooth (46) has a substantially saw-tooth profile and is carried by said lid (17), the second tooth (46) engaging in an axially free, angularly integral manner with said first tooth (47) during disengagement of the lid (17) from said seat (15) when said package (1) is first opened.