HK1170990A - Folding unit for pourable food product packaging machines - Google Patents

Description

Folding unit for pourable food product packaging machines

Technical Field

The present invention relates to a folding unit for a packaging machine for continuously producing sealed packages of pourable food products from a tube of packaging material.

Background

It is well known that many food products, such as fruit juices, pasteurized or UHT (ultra high temperature treated) milk, wine, potato paste, etc., are sold in packages made of sterilized packaging material.

A typical example of this type of packaging is the parallelepiped-shaped packaging for liquid or pourable food products, known as Terra Brik Aseptic (registered trademark), which is made by folding and sealing a laminated strip packaging material.

The packaging material has a multilayer structure, which essentially comprises a substrate layer for stiffness and strength, which may comprise a layer of fibrous material, such as paper, or a layer of mineral-filled polyethylene material; and a plurality of layers of heat-seal plastic material, such as polyethylene film, covering both sides of the base layer.

In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material also comprises a layer of gas and light barrier material, for example aluminium foil or ethylene vinyl alcohol copolymer (EVOH), which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material forming the inner face of the package eventually contacting the food product.

As is known, packages of this type are produced on fully automatic packaging machines, on which a continuous tube is formed from a web-fed packaging material; the web of packaging material is sterilized on the packaging machine, for example by applying a chemical sterilizing agent, such as a peroxide solution, which is removed from the surface of the packaging material once sterilization is completed, for example by evaporation by heating; the web of packaging material thus sterilized is maintained in a closed, sterile environment and is folded and sealed longitudinally to form a vertical tube.

The tubular body is filled continuously downwards with the sterilized or sterile-processed food product and is sealed and then cut along equally spaced cross sections to form pillow packs, which are then fed to a folding unit to form finished packages, for example substantially parallelepiped-shaped packages.

More specifically, the pillow packs substantially comprise a main portion of parallelepiped shape; and opposed top and bottom ends projecting laterally on opposite sides of the main portion and defining respective triangular end flaps for folding onto the main portion.

The longitudinal sealing strip formed when sealing the packaging material to form the vertical tube extends along the pillow packs; and the end portion of each pillow pack has a respective transverse sealing band perpendicular to the opposite longitudinal sealing bands and defining respective end flaps projecting from the top and bottom of the pack.

The end portion of each pillow pack tapers from the respective end flap toward the main portion and is squeezed toward each other by the folding unit to form the flat opposite end walls of the pack while folding the end flaps onto the respective walls of the main portion.

Packaging machines of the above-mentioned type are known in which pillow packs are folded to form parallelepiped-shaped packages by means of ｃA folding unit as disclosed, for example, in EP- ｃA-1726526 in the name of the same applicant.

The folding unit disclosed in EP- ｃA-1726526 basically comprises:

-a chain conveyor feeding the packages along a forming path from a supply station to an outfeed station;

-a fixed elongated guide member facing the conveyor chain and positioned at a distance therefrom and cooperating cyclically with each pack to flatten the respective top end portion of the pack and thus fold the respective tab onto such top end portion; and

folding means cyclically cooperating with each pack to flatten the respective bottom end and thus fold the respective flap onto the bottom end.

More precisely, the folding device comprises a plurality of movable plates which at least partially define opposite links of the chain conveyor and are hinged to such opposite links.

Each panel defines an impact surface that receives the relative pack through the relative bottom flaps and rotates between a first operative position and a second operative position.

More specifically, in the first operating position occupied by the initial portion of each plate along the forming path, the opposite impact surfaces form an angle of more than 90 degrees with the axis of the opposite packages, so as to fold the packages in the direction of travel of the packages along the forming path. In a second operating position occupied along the remainder of the forming path, the impact surface is instead turned towards the pack, with which it cooperates to complete the folding of the opposite flaps onto the pack.

The folding unit further comprises a fixed first cam to move the impact surface from the opposite second operative position to the opposite first operative position; and a fixed second cam means located immediately upstream of the supply station and for moving the impact surface from the first to the second opposite operating position.

The folding action is therefore mainly dependent on the energy associated with the impact between the impact surface and the bottom end of the package.

As a result, the folding action is substantially dependent on the fact that the packages are fed to the folding action at a certain speed value. In other words, the folding action can only be performed efficiently when the output speed of the packaging machine is higher than a certain value.

There is a need in the industry to correctly fold the flaps of the bottom end of the packs, even when the pack speed is particularly low, in order to obtain a folding unit suitable for packaging machines with a low output speed.

Furthermore, there is a need in the industry to reduce the stress on the package in order to improve the overall folding quality of the package.

There is also a need in the industry to meet the above-mentioned requirements in connection with packages made of a wide range of packaging materials, in particular particularly rigid packaging materials.

Finally, there is a need in the industry to easily fold different types of packages having opposing bottom flaps that are more or less pinched to opposing main portions.

Disclosure of Invention

It is an object of the present invention to provide a folding unit for a pourable food product packaging machine, designed to satisfy at least one of the above requirements.

According to the present invention, there is provided a folding unit for a pourable food product packaging machine, as claimed in claim 1.

Drawings

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

fig. 1 shows a side view of a folding unit for producing packages of pourable food products from sealed pillow packs, according to the present invention, with portions removed for clarity;

fig. 2 shows a perspective view of the folding unit of fig. 1 on a larger scale, with parts removed for clarity;

figures 3 to 8 show a side view, on a larger scale, of a pillow pack folding sequence carried out along a portion of the pack feed path, with portions removed for clarity; and

figure 9 shows a perspective view of a pillow pack in the form of a supply to the folding unit of figure 1.

Detailed Description

Number 1 in fig. 1 indicates as a whole a folding unit for a packaging machine (not shown) for continuously producing parallelepiped-shaped sealed packages 2 of pourable food products, such as pasteurized or UHT milk, fruit juice, wine, etc., from a known tube (not shown) of packaging material.

The tubular body is formed in known manner upstream from unit 1 by longitudinally folding and sealing a web (not shown) of known heat-seal sheet material comprising a layer of paper material covered on both sides with layers of heat-seal plastic material, for example polyethylene. In the case of aseptic packages 2 for long-storage products, such as UHT milk, the packaging material comprises a layer of oxygen-barrier material, for example aluminium foil, which is superimposed on one or more layers of heat-seal plastic material eventually forming the inner face of the package contacting the food product.

The tube of packaging material is then filled with the food product for packaging and is sealed and cut along equally spaced cross sections to form a plurality of pillow packs 3 (fig. 9), these pillow packs 3 being then transferred to unit 1, where they are folded mechanically to form respective packages 2.

With reference to fig. 9, a longitudinal sealing band 4, formed for producing a tube of packaging material from a web folded into a cylinder, extends along one side of each pack 3, which is closed at the opposite ends by respective transverse sealing fins 5, 6, which transverse sealing fins 5, 6 are perpendicular to and connected to the longitudinal sealing band 4.

Each pack 3 has an axis a parallel to longitudinal sealing band 4 and comprises a main portion 7 of parallelepiped shape; and opposite top and bottom ends 8, 9, respectively, which taper from the main portion 7 towards the respective transverse sealing fin 5, 6.

More specifically, main portion 7 of each pack 3 is laterally bounded by two flat rectangular walls 10 parallel to each other and to axis a, and by two flat rectangular walls 11 extending perpendicularly between walls 10.

Each end portion 8, 9 is defined by two walls 12, each substantially in the shape of an isosceles trapezium and each slightly inclined towards each other with respect to a plane perpendicular to axis a, and having a minor edge defined by a respective terminal edge of wall 10 of main portion 7, and a major edge interconnected by respective sealing fins 5, 6.

As best shown in fig. 9, the longitudinal sealing band 4 extends between the transverse sealing fins 5 and 6 and along all of one wall 10 and the corresponding wall 12 on the same side as the wall 10.

Each sealing fin 5, 6 forms a respective substantially elongated rectangular end flap 13, 14, which flaps 13, 14 project from the relative pack 3 in the direction of axis a; and two substantially triangular flaps 15, 16, which flaps 15, 16 project laterally on opposite sides of the main portion 7 and are defined by the ends of the opposite walls 12.

More precisely, each end flap 13, 14 extends along a direction F orthogonal to axis a and comprises a central zone 17 and a pair of lateral zones 18.

To form pack 2, unit 1 flattens ends 8, 9 of relative pack 3 downwards towards each other, and at the same time folds respective flaps 13, 14 onto ends 8, 9.

With reference to figures 1 to 8, unit 1 substantially comprises a chain conveyor 20 for feeding packages 3 continuously along a mainly straight horizontal forming path B from a supply station 21 to an outfeed station 22 (both schematically shown); and first folding means 23 and second folding means 24, which cooperate cyclically with each pack 3 to flatten respective end portion 8, 9 of pack 3 and thus fold respective tab 13, 14 onto end portion 8, 9.

The conveyor 20 comprises at least one gear and in the example shown a driving gear 25 and a driven gear 26; and a hinged chain 27, which surrounds gears 25, 26 and meshes with gears 25, 26 and supports a plurality of flat rectangular paddles 28, each of rectangular paddles 28 projecting from chain 27 and cooperating with a corresponding wall 10 of relative pack 3 and pushing corresponding wall 10 of relative pack 3 to feed the packs along path B.

The chain 27 comprises a straight horizontal top branch 30; a bottom branch 31 substantially parallel to branch 30; and two curved C-shaped portions 32, 33, the C-shaped portions 32, 33 being positioned with their recesses facing, connecting, the branches 30 and 31, and the middle of the C-shaped portions 32, 33 defining the supply station 21 and the output station 22, respectively.

The path B comprises a straight main portion B defined by the branches 30 of the chain 27₁(ii) a And two curved ends B for supply and discharge respectively₂、B₃End part B₂、B₃Defined by respective tops 32a, 33a of portions 32, 33 of chain 27, tops 32a, 33a extending between respective stations 21, 22 and branch 30. Branch 30 and portions 32a, 33a of portions 32, 33 thus define a conveying portion of chain 27 to convey packages 3 from station 21 to station 22, while branch 31 and the remaining portions of portions 32, 33 define a return portion of chain 27 to feed paddle 28 from station 22 to station 21.

The chain 27 comprises a plurality of articulated connections 35 defined by substantially flat rectangular plates, from which articulated connections 35 respective paddles 28 project perpendicularly. More specifically, each paddle 28 extends from a point intermediate relative to connecting member 35 and divides the latter into two substantially rectangular bearing portions 36, 37 for supporting packages 3, bearing portions 36, 37 differing in length along path B and positioned respectively upstream and downstream of paddle 28 along path B. More specifically, along path B, portion 37 is longer than portion 36.

Given the configuration of conveyor 20, paddle 28 follows portion B of path B₁But is placed vertically.

Each package 3 is positioned on conveyor 20 with end 9 in contact with the conveying portion of chain 27, with one wall 10 resting on the opposite paddle 28 and axis a parallel to paddle 28 and crosswise to path B.

At supply station 21, each pack 3 is fed onto conveyor 20 in a feed direction C, coaxial with axis a of pack 3, and in an input position in which end 9 and opposite end flap 14 are positioned facing the conveying portion of chain 27. Similarly, each completed package 2 is removed from conveyor 20 in a horizontal output position (not shown, as it is not necessary for a clear understanding of the invention).

More specifically, along the curve B of the path B₂Given the natural spacing created between adjacent links 35 of chain 27, end portion 9 of each pack 3 is only loosened onto bearing portion 37 of relative link 35; and a straight portion B along path B₁End 9 of each pack 3 contacts both bearing portion 37 of relative link 35 and bearing portion 36 of preceding link 35.

With particular reference to fig. 1, the folding device 23 comprises a fixed elongated guide member 40, the guide member 40 being positioned facing the conveying portion of the chain 27 and at a distance from the conveying portion of the chain 27, the guide member 40 being along a portion B of the path B₁And part B₂The joined-up portions extend and define, on the side facing chain 27, a concave cam surface converging with the conveying portion and cooperating with end portion 8 of each pack 3 to flatten it downwards towards chain 27.

The action of guide member 40, combined with the force of gravity, loosens packages 3 downwards towards the conveying portion of chain 27, flattening both end portions 8, 9 of packages 3.

Two fixed sides 41 (not shown in fig. 1) located on opposite sides of the conveyor 20 provide lateral retention of the packages along path B.

Folding device 24 also comprises a plurality of movable plates 42 hinged to relative connectors 35 about relative axes D, crosswise to path B and to axis a of relative pack 3.

With particular reference to figures 3 to 7, each panel 42 defines a surface 43 suitable for cooperating with a flap 14 of an opposite pack 3.

More precisely, when it reaches station 21, each plate 42 is arranged in a rest position (fig. 4) in which the opposite surface 43 defines an angle γ with direction C on the opposite side to chain 27.

Moreover, after impact with flaps 14, each plate 42 is moved at station 21 towards a first operating position (fig. 5) in which opposite surface 43 defines an angle α with respect to axis a of pack 3. More precisely, the angle α exceeds 90 degrees and opens in the direction of the forming path B. In the depicted embodiment, the angle α is equal to 140 degrees.

Finally, when following part B₂During movement, each plate 42 moves towards a second operating position (figure 7) in which relative surface 43 defines an angle β smaller than angle α with respect to axis a of pack 3.

Due to the fact that angle β is smaller than angle α, each surface 43 causes flaps 14 to be partially folded towards relative pack 3 while moving from the first operating position to the second operating position.

Preferably, the angle of rotation of the surface 43 between the first and second operating positions, i.e. the angle α - β, ranges between 40 and 50 degrees and is equal to 45 degrees in the depicted embodiment.

The folding means 24 advantageously comprise a plurality of cams 80, the cams 80 being carried by the chain 27 and each cooperating, in use, with the opposite plate 42 to move the opposite surface 43 between the opposite first and second operating positions.

More precisely, cam 80 cooperates with surface 50, surface 50 being opposite surface 43 of plate 42.

In more detail, each cam 80 is carried by a portion 37 of the opposite first link 35 and cooperates with a surface 43 of the opposite plate 42 carried by a portion 25 of the second link 35, this second link 35 being located immediately upstream of the first link 35 with respect to the direction of advance of the chain 27.

In this wayFollowing the curve B of the path B, the first and second connectors 35 follow₁Moving relative to each other, each plate 42 slides onto a corresponding cam 80, causing the opposite surfaces 43 to rotate from the opposite first position to the opposite second position.

Furthermore, each cam 80 substantially comprises a first surface 81 and a second surface 82 (fig. 4 to 8) which interact with the surface 50 and are inclined with respect to each other.

More precisely, the surface 81 is arranged upstream of the opposite surface 82 with respect to the advancing direction of the chain 27.

In other words, along the portion B₁When moved, each plate 42 cooperates first with surface 81 and then with surface 82.

As for part B of path B₁Said surface 82 is substantially parallel to portion B₁And surface 81 is inclined relative to surface 82 and rises toward surface 82.

The folding device 24 also comprises (fig. 1 and 2):

a pair of idle wheels 100 supported by a fixed structure (not shown) of the folding unit 1 and rotatable about a common axis E; and

a pair of tracks 101 converging towards guide member 40 and each comprising a portion 102 arranged below respective wheel 100 and respective portion 103, portion 103 being arranged along portion B according to pack 3₁Downstream of the advancing portion 102.

More precisely, the wheels 100 and the track 101 are arranged on respective opposite lateral sides of the chain 27.

Axis E is substantially orthogonal to the plane in which path B lies, portion 102 is inclined with respect to branch 30, and portion 103 is inclined with respect to both portion 102 and branch 30.

More precisely according to portion B along which pack 3 follows₁Is advanced, portion 102 approaches axis E and portion 103 approaches branch 30.

In other words, both portion 102 and portion 103 are raised.

Wheels 100 and portions 102 of respective tracks 101 define respective paths 108, through which lateral zones 18 of packs 3 circulate.

Furthermore, the wheel 100 and the portions 102, 103 are arranged in correspondence with the portion B₁Portion B of adjacent path B₂At the end of (a).

Due to the fact that rails 101 converge towards guide members 40, lateral zones 18 of each pack 3 are partially folded towards main portion 7 of pack 3 along with central zone 17 of such pack 3 as they pass through passage 108.

At the same time, flap 16 of each pack 3 is pressed by wheel 100 against track 101.

As they slide onto portion 103 of track 101, lateral zones 18 of each pack 3 are folded completely onto main portion 7 of pack 3.

The operation of unit 1 will be described with reference to one pack 3 and from an initial moment in which pack 3 is fed in direction C onto portion 37 of opposite link 35 of chain 27 of conveyor 20.

As shown in particular in fig. 1 and 3, pack 3 is placed with end flap 14 facing portion 37 of connecting member 35 and sliding on one wall 40 along opposite paddle 28, so that flap 14 is parallel to paddle 28.

When reaching the supply station 21, the plate 42 of the connecting member 35 is arranged in the rest position (fig. 4).

Upon impact with pack 3 at feed station 21 (fig. 4), plate 42 of link 35 rotates clockwise about axis D to reach the first operating position (fig. 5).

The movement of paddle 28 and the thrust exerted by it move packages 3 along portion B of path B₂In part B of path B₁Is erected to a vertical position in the vicinity of the starting point. In the movementIn the process, end 8 of pack 3 cooperates in a sliding manner with a guide member 40, which guide member 40 converges with chain 27, as described above, and therefore cooperates with chain 27 to flatten ends 8 and 9 downwards.

As this occurs, the plate 42 slides onto the first and second surfaces 81 and 82 of the corresponding cams 80 carried by the connecting member 35 arranged immediately downstream along the path B. Due to the configuration of the cam 80, the plate 42 moves from the first operative position to the second operative position (fig. 6 and 7).

Thus, central region 17 of flap 14 is folded towards main portion 7 of pack 3.

As this occurs, lateral zone 18 of flap 14 passes through passage 108, slides onto portion 102 of track 101 and is partially folded onto main portion 7 of pack 3.

More precisely, the flap 16 of the pack 3 cooperates with the wheel 100 and the lateral zone 18 is folded by the portion 102 towards the main portion 7.

Thereafter, the connecting member 35 follows a portion B of the path B₁Moves and the partially folded lateral zone 18 of flap 14 slides onto portion 103 of track 101.

Due to the fact that portion 103 is raised and converges towards guide member 40, lateral zone 18 is completely folded onto main portion 7 of pack 3.

The complete folding of the lateral zones 18 causes the central zone 17 to be completely folded over the main portion 7 of the wrapper 3.

Once flaps 14 have been completely folded onto main portion 7, pack 3 may undergo a further forming operation, not described or illustrated as not forming part of the present invention, and pack 3 is then unloaded from conveyor 20 at an outfeed station 22.

Once pack 3 is free, connecting member 35 is arranged in the rest position by its weight and fed back to supply station 21.

The advantages of the unit 1 according to the invention will be clear from the foregoing description.

In particular, thanks to the fact that the cam 80 is carried by the chain 27, it is possible to rotate the plate 42 and therefore the surface 43 by an angle greater than the angle of rotation of the impact surface of the folding unit described in the introductory part of the present description.

As a result of this particularly increased angle of rotation of the panel 42 between its first and second operative positions, the end flap 14 slides substantially onto the surface 43 arranged in the first operative position, without striking the opposite connecting element 35.

Thus, folding unit 1 ensures folding of end flaps 14 when the speed of packs 3 is particularly low, i.e. the packaging machine has a low speed, since folding of end flaps 14 is substantially independent of the impact between end flaps 14 and surface 43.

In this way, the mechanical stresses on packages 3 are reduced and the overall quality of folded packages 2 is greatly improved.

For the same reason, even the end flaps 14 of packs 3 made of a wide range of packaging materials, in particular particularly stiff packaging materials, are effectively folded by unit 1.

Finally, the maximum lift of the plate 42 with respect to the opposite axis D can be easily varied by simply modifying the shape of the cam 80.

It is thus possible to fold different types of packs 2 with how much of the end flap 14 is pressed onto the main portion 7 by modifying the shape of the cam 80.

Clearly, changes may be made to unit 1 without, however, departing from the protective scope defined in the accompanying claims.

Claims (8)

1. A folding unit (1) for producing packages (2) of pourable food products from sealed packages (3), said packages (3) each having a longitudinal first axis (a) and comprising at least one first end flap (14) to be folded, said first end flap (14) projecting in the direction of said longitudinal first axis (a); the first end flap (14) comprises, in a direction (F) transverse to the first axis (A), a central zone (17) and a pair of lateral zones (18) arranged on opposite sides of the central zone (17);

the unit (1) comprises:

-a movable conveying member (20) fed with a plurality of said packs (3) by an end corresponding to the opposite first end flap (14) and feeding said packs (3) along a forming path (B); and

-folding means (24) interacting with each of said packs (3) along said forming path (B) to fold the opposite first end flap (14) onto said opposite pack (3);

said folding device (24) comprising a plurality of plates (42) carried by said conveying member (20) and in turn comprising respective first surfaces (43);

each of said first surfaces (43) cooperates, in use, with at least said central zone (17) of said first end flap (14) to be folded of the relative pack (3) and is movable with respect to the relative pack (3) with which it cooperates between a first and a second opposite position, so as to fold at least said central zone (17) of said first end flap (14) onto said pack (3);

characterised in that said folding means (24) comprise a plurality of cams (80), said cams (80) being carried by said conveying member (20) and cooperating, in use, each with said relative plate (42) to move said relative first surface (43) between said relative first and second positions.

2. The folding unit of claim 1, characterized in that said conveying means (20) comprise a plurality of consecutive links (35) articulated with respect to each other; each of said first opposite surfaces (43) is rotatable with respect to a first of said connecting elements (35), and the corresponding cam (80) is fixed to a second of said connecting elements (35) immediately adjacent to said first connecting element (35) and downstream of said first connecting element (35), so as to advance according to the advancing direction of the packages (3) along said path (B).

3. The folding unit of claim 2, characterized in that each cam (80) comprises a second and a third surface (81, 82) inclined with respect to each other and cooperating, in use, with said first opposite surface (43).

4. The folding unit of claim 2 or 3, characterized in that the conveying member (20) is a chain conveyor (20).

5. The folding unit according to any one of the preceding claims, further comprising a folding device (23), said folding device (23) interacting, in use cyclically, with the second end flap (13) of each pack (3) along the forming path (B); the second end flap (13) is opposite the first end flap (14).

6. The folding unit of claim 5, characterized in that it comprises:

-a pair of wheels (100) arranged on opposite sides of the transport member (20) and rotatable along a second axis (E) which is fixed with respect to the transport member (20); and

-a pair of rails (10) converging towards said further folding member (23), fixed with respect to said conveying member (20) and arranged on opposite sides of said conveying member (20);

said wheel (100) and said track (101) defining a respective passage (108) which, in use, is cyclically crossed by said lateral zone (18) of the first end flap (14) of each pack (3);

the wheel (100) is adapted to cooperate cyclically with a respective flap (16) interposed between the main portion (7) and the first end flap (14) of each pack (3), and the track (101) is adapted to cooperate cyclically with the lateral zone (18) of the first end flap (14) to fold the lateral zone (18) of such first end flap (14) towards the opposite main portion (7).

7. The folding unit of claim 6, wherein said track (101) comprises a first portion (102) facing the respective wheel (100) and defining with the respective wheel (100) the respective passage (108), and a second portion (103) arranged downstream of said first portion (102), said second portion (103) advancing according to the advancing direction of the packs (3) along said path (B);

the second portion (103) cooperates cyclically, in use, with the lateral zones (18) of each pack (3) to complete the folding of the first end flap (14) onto the pack (3).

8. The folding unit of claim 7, characterized in that the path (B) comprises a curved supply (B)₂) And a straight main portion (B)₁) Each first plate (42) being along the supply portion (B)₂) Cooperating with said corresponding cam (80) and moving with respect to said corresponding cam (80), said main portion (B)₁) Is arranged at the supply part (B)₂) Downstream, advancing according to said advancing direction of said packages (3) along said path (B);

the wheel (100) and at least the first portion (102) of the track (10) are arranged with the main portion (B)₁) Adjacent said supply portion (B)₂) At the end of (a).