HK1130744B - Folding unit for producing sealed packages of pourable food products - Google Patents

Description

Folding unit for producing sealed packages of pourable food products

Technical Field

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

Background

Many pourable food products such as beverages, fruit juices, pasteurized or UHT (ultra-high-temperature treated) milk, wine, tomato sauce etc. are sold in packages made of sterilized packaging material.

An example of this type of package is a parallelepiped-shaped package for liquid or pourable food products, an example of which is known under the trademark Tetra Brik Aseptic (registered trademark).

Another example of this type of package is a gable-top package for liquid or pourable food products, the following description being directed purely to such packagesThe extract is by way of example, as described in European patent EP1440010 and in published patent application EP1584563, this example being Tetra Gemina^TMTrade names of Aseptic are well known.

In both cases, the packages are produced by folding and sealing the laminated strip packaging material.

The packaging material has a multilayer structure essentially comprising a substrate layer providing stiffness and strength, which may comprise a layer of fibrous material, such as paper, or a layer of mineral-filled (mineral-filled) polypropylene material; and a plurality of layers of heat-seal plastic material, such as polyethylene film, covering both sides of the substrate 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 ethyl vinyl alcohol (EVOH) film, 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, such packages are produced on fully automatic packaging machines, on which a continuous tube is formed from a web-fed packaging material. More specifically, the web of packaging material is unwound from a reel on a packaging machine and passed through an aseptic chamber where it is sterilized, for example by applying a sterilizing agent such as hydrogen peroxide, whereupon the sterilizing agent is evaporated by heating and/or subjecting the packaging material to radiation of a suitable wavelength and intensity; and the web of packaging material thus sterilized is kept in a closed, sterile environment, folded into a cylinder and sealed longitudinally to form a continuous tube in a known manner.

The tube of packaging material, which in practice forms an extension of the aseptic chamber, is fed continuously in the vertical direction, is filled with the sterilized or sterile-processed food product, and is fed through a forming unit for producing the individual packages. I.e. the tube is sealed along a number of equally spaced cross sections inside the forming unit to form a continuous strip of pillow packs, which are connected to each other with respective transverse sealing strips, i.e. sealing strips extending perpendicularly to the direction of travel of the tube.

More specifically, each pillow pack comprises a parallelepiped main portion; and opposite end portions, respectively top and bottom, inclined from the main portion towards the respective sealing strip. Each end portion has substantially triangular flaps (or wings) projecting from opposite sides of the main portion, and each end portion also has a narrow rectangular projection projecting from the associated sealing strip.

The pillow packs are separated by cutting the relative transverse sealing strips and then folded further to form the respective finished packages.

In the case of parallelepiped-shaped packages, the end portions are first flattened, followed by folding the top flaps onto the respective transverse walls of the main portion and the bottom flaps onto the flattened bottom end portions.

In the case of gable-top packages, on the other hand, the top end portion of the package is folded to form two inclined walls joined at the sealing strip, and the flaps of the bottom end portion are folded onto the already flattened bottom end portion.

In industrial production there is a felt need for versatile folding units, i.e. they are designed to produce packages of different heights quickly and with few operations, i.e. from pillow packages of different sizes of the main part.

Disclosure of Invention

It is an object of the present invention to provide a folding unit for packaging machines of pourable food products, designed to satisfy the above-mentioned requirements.

According to the present invention, there is provided a folding unit for producing sealed packages of pourable food products from respective packages, each package having a main portion folded into a desired shape and opposite end portions folded to form respective folded ends of a relative final package; said unit being characterized in that it comprises: a first folding station, in turn having first retaining means for securing each of said packages by an associated first end portion, and first folding means for folding an associated second end portion of said packages; and a second folding station located downstream of the first folding station in the travelling direction of the packs, said second folding station in turn comprising second retaining means for securing each of the packs by the relative folded second end portion, and second folding means for folding the relative first end portion.

Drawings

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

figure 1 shows a side view of a folding unit according to the invention;

FIG. 2 shows a web of packaging material having a plurality of fold lines (crease pattern);

FIG. 3 shows a gable top package produced by the folding unit of FIG. 1;

figures 4 to 7 show a first folding assembly of the unit shown in figure 1, for forming the gable portion of the package of figure 3;

fig. 8 shows a component part (a component part) of the first folding assembly of fig. 4 to 7 interacting with a pillow package being formed into a chevron section;

FIG. 9 shows a detail of the unit shown in FIG. 1;

FIG. 10 shows the components interacting with the detail of FIG. 9;

figures 11 and 12 show perspective views of two working configurations of the second folding assembly of the unit of figure 1, for forming the bottom wall of the package of figure 3; and

fig. 13 shows a detail of fig. 11 and 12 on an enlarged scale.

Detailed Description

Number 1 in fig. 1 indicates as a whole a folding unit of a packaging machine (not shown) for continuously producing gable-top sealed packages 2 (fig. 3) of a pourable food product, such as pasteurized or UHT milk, fruit juice, wine, etc., from a known tube (not shown) of packaging material.

The tube is formed upstream of the unit 1 in a known manner by folding and sealing a web of heat-seal sheet material in the longitudinal direction.

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

In the case of aseptic packages 2 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 ethyl vinyl alcohol (EVOH) film, 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 packages 2 eventually contacting the food product.

With particular reference to fig. 2, the web of packaging material comprises a crease pattern 10, i.e. a plurality of folding lines along which the material is folded during the folding operation to form first pillow packs 3 and subsequently packages 2.

Crease pattern 10 comprises four transverse fold lines 11, 12, 13, 14. The lines 11, 12 are located close to the ends of the packaging material and define respective top and bottom sealing areas (or zones) 11a, 12 a.

Crease pattern 10 comprises, in a known manner, four longitudinal fold lines 15, 16, 17, 18 extending between transverse fold lines 13, 14.

The lines 15, 18 are located close to the transverse edges 19 of the packaging material, while the lines 16, 17 are sandwiched between the lines 15 and 18.

Crease pattern 10 also comprises a plurality of first additional fold lines in the area between lines 11 and 13.

These first additional lines comprise two folding lines 22, 23 extending obliquely between the lines 11, 13 and converging from the line 11 to the line 13; and two fold lines 24, 25 extending between the lines 11, 13 and converging from the line 13 to the line 11.

The lines 22, 23, 24, 25 start at respective intersection points 15a, 18a, 16a, 17a of the respective lines 15, 18, 16, 17, and in the embodiment shown these lines 22, 23, 24, 25 are slightly inclined in the longitudinal direction.

Lines 22 and 24, the portion of line 13 between points 15a and 16a, and the portion of line 11 between the intersection of lines 11 and 24 and the intersection of lines 22 and 11 define a region 26. Similarly, lines 23 and 25, the portion of line 13 between points 17a and 18a, and the portion of line 11 between the intersection 11f of lines 11 and 23 and the intersection of lines 11 and 25 define a region 27.

Lines 24 and 25, the portion of line 11 between the intersections of lines 24, 25 with line 11, and the portion of line 13 between the intersections of lines 24, 25 with line 13 define a panel a sandwiched between regions 26 and 27 in the form of an isosceles trapezoid with the oblique sides converging from line 13 to line 11.

On the opposite side to panel a (or the opposite side), lines 22 and 23, the portion of line 11 extending between points 11e and 11f, and the portion of line 13 extending between points 15a and 18a on the opposite side to panel a define a panel B, which is sandwiched between areas 26 and 27 and is in the form of an isosceles trapezoid with the oblique side converging from line 13 to line 11.

Crease pattern 10 comprises, in area 26, two fold lines 30, 31, starting respectively at points 15a, 16a and connected to each other at a point 11b along line 11 to form an isosceles triangle, a portion of line 13 extending between points 15a and 16 a. Similarly, crease pattern 10 comprises, in area 27, two further fold lines 32, 33, which start at points 17a, 18a, respectively, and are connected to each other at a point 11c along line 11 to form an isosceles triangle, a portion of line 13 extending between points 17a and 18 a.

The portion of lines 31, 24 extending with line 11 between the point 11b and the intersection of lines 24 and 11 defines the outer boundary of the triangular panel C adjacent to panel a. And similarly the portion of line 32, 25 extending with line 11 between the point 11C and the intersection of lines 25 and 11 defines the outer boundary of a triangular panel D adjacent to panel a and on the opposite side of panel C.

Crease pattern 10 comprises three lines 34, 35, 36 in area 26 and three lines 37, 38, 39 in area 27; lines 34, 35, 36 extend from points 15a, 16a, 11b, respectively, to a point 45 within the isosceles triangle in area 26; and lines 37, 38, 39 extend from points 17a, 18a, 11c, respectively, to a point 46 within the isosceles triangle in area 27.

Lines 34, 35 extend symmetrically on opposite sides of an extension of line 36; while lines 37, 38 extend symmetrically on opposite sides of an extension of line 39.

Thus forming in area 26 a panel E in the form of an isosceles triangle and bounded by lines 34, 35 and the portion of line 13 extending between points 15a, 16 a; and also forms a triangular panel F bounded by lines 30, 34, 36; and a triangular panel G bounded by lines 31, 35, 36.

Similarly, in area 27 a panel H is formed, in the form of an isosceles triangle and bounded by lines 37, 38 and the portion of line 13 extending between points 17a, 18 a; a triangular panel L bounded by lines 32, 37, 39 is also formed; and triangular panels M bounded by lines 33, 39, 38.

Crease pattern 10 also includes, in region 26, line 40 extending between intersection 11e of lines 11 and 22 and point 47, which is substantially at the midpoint of line 30. And, likewise, crease pattern 10 also includes, in region 27, line 41 extending between intersection 11f of lines 11 and 23 and point 48, which is substantially at the midpoint of line 33.

Thus forming a triangular panel N in the region 26, which panel N is bounded by the portions of the lines 22, 40 and 30 extending between the points 15a and 47; and also forms a triangular panel O bounded by line 40, the portion of line 11 extending between points 11e and 11b, and the portion of line 30 extending between points 11b and 47.

Similarly, a triangular panel Q is formed in the region 27, the panel Q being bounded by the portions of the lines 23, 41 and 33 extending between the points 18a and 48; and also forms a triangular panel P bounded by line 41, the portion of line 33 extending between points 11c and 48, and the portion of line 11 extending between points 11c and 11 f.

Crease pattern 10 also includes a plurality of second additional fold lines, indicated by reference numeral 20, in the area between line 14 and sealed area 12 a. The lines indicated by reference numeral 20 are folded to form the transverse flaps 128 (fig. 11 and 12), after which these flaps are folded to form the bottom wall 62 of the package 2.

The lines indicated with 20 comprise two folding lines 73, 74 extending obliquely between the lines 12, 14 and converging from the line 12 to the line 14; and two fold lines 75, 76 extending obliquely between the lines 12, 14 and converging from the line 14 to the line 12.

Lines 73, 74, 75, 76 originate at respective intersections 14a, 14d, 14b, 14c of lines 15, 18, 16, 17 with line 14.

Lines 75 and 76, the portion of line 14 extending between points 14b and 14c, and the portion of line 12 extending between the intersection of lines 75, 76 and line 12 define a panel V in the form of an isosceles body with oblique sides converging from line 14 to line 12.

The portions of lines 73 and 74, on the side opposite to panel V, where line 14 extends between points 14a and 14d, and the portions of line 12, on the side opposite to panel V, between the intersections of lines 73, 74 and line 12, define a panel W in the form of an isosceles trapezoid, the panel W having inclined side edges converging from line 14 to line 12.

Crease pattern 10 comprises two lines 77, 78 running between respective points 14a, 14b and one point 12c along line 12 and located halfway between the intersections of lines 73, 75 and line 12. Similarly, crease pattern 10 includes two lines 79, 83 running between respective points 14c, 14d and one point 12d along line 12 and halfway between the intersections of lines 74, 76 and line 12.

Lines 75 and 78, and the portion of line 12 extending between the point 12c and the intersection of lines 12 and 75 define a triangular panel I adjacent panel V; lines 73 and 77, and the portion of line 12 extending between the point 12c and the intersection of lines 12 and 73, define a triangular panel K adjacent to panel W; and lines 77 and 78, and the portion of line 14 extending between points 14a and 14b, define a triangular panel J sandwiched between panels I and K.

Lines 76 and 79, the portion of line 12 extending between point 12d and the intersection of lines 12 and 76 defining a triangular panel X adjacent panel V; lines 74 and 83, the portion of line 12 extending between point 12d and the intersection of lines 12 and 74 defining a triangular panel Z adjacent panel W; and lines 79 and 83, the portion of line 14 extending between points 14c and 14d defining a triangular panel Y sandwiched between panels X and Z.

Once formed, the tube of packaging material is filled with the food product to be packaged, and is sealed and cut along equally spaced cross sections to form a plurality of pillow packs 3 (as shown in figure 1).

Fig. 8 shows a partial view of pack 3 at the beginning of the formation of gable top 61 (fig. 3) of corresponding package 2.

More specifically, packs 3 extend along axis R and each comprise, in a known manner, a parallelepiped-shaped main portion 49, and opposite end portions 50a, 50b (only one end is shown in fig. 8) inclined by main portion 49 towards a respective transverse sealing strip 53 of packs 3.

Portion 49 corresponds to the area of the web extending between lines 13 and 14. More specifically, the regions are folded along lines 15, 16, 17 and 18 to form two parallel walls 49a (only one wall is shown in fig. 8) and two parallel walls 49b (only one wall is shown in fig. 8) perpendicular to walls 49 a.

Wall 49a corresponds to the area between lines 16 and 17 and between lines 15 and 18, respectively; and wall 49b corresponds to the area between lines 15 and 16 and between lines 17 and 18, respectively.

The portions 50a, 50b correspond to the areas of the web extending between the lines 11 and 13 and between the lines 12 and 14, respectively; while strip 53 corresponds to regions 11a, 12a of the web of packaging material.

Each portion 50a, 50b is defined by a respective pair of walls 51a, 51b and 54a, 54b (fig. 1), which are substantially in the form of an isosceles trapezium, which are slightly inclined towards each other with respect to a plane perpendicular to longitudinal axis R of pack 3, and whose longer edges are defined by the respective end edges of opposite wall 49a, while relative strip 53 connects the shorter edges to each other.

More specifically, walls 51a, 51B of portion 50a correspond respectively to panels a, B of the web of packaging material.

Similarly, the walls 54a, 54b of the portion 50b correspond respectively to the panels V, W of the web of packaging material.

Each pack 3 comprises, on wall 51a of portion 50a, two substantially triangular portions 52a projecting laterally on opposite sides of wall 51a and defined by end portions of wall 51 a.

Similarly, each pack 3 comprises, on wall 51b of portion 50a, two substantially triangular portions 52b projecting laterally on opposite sides of wall 51b and formed by end portions of wall 51 b.

With reference to portion 50a, portions 52a of wall 51a correspond respectively to panels C and D, while portions 52b of wall 51b correspond respectively to panels N, O and Q, P of the web of packaging material.

Each pack 3 comprises, on wall 54a, two substantially triangular portions 59a (shown in figures 11 and 12 with respect to pack 3, portion 50a of which has been folded to form portion 61 of package 2), which project laterally on opposite sides of wall 54a and are formed by end portions of wall 54 a.

Similarly, each package comprises, on the wall 54b, two substantially triangular portions 59b (also shown only in fig. 11 and 12) projecting laterally on opposite sides of the wall 54b and formed by end portions of the wall 54 b.

Portions 59a of wall 54a correspond to panels I and X, respectively, of the web of packaging material, while portions 59b of wall 54b correspond to panels K and Z, respectively, of the web of packaging material.

Each portion 52a of wall 51a is connected to a corresponding portion 52b of wall 51b by a respective transverse surface 55 projecting from one end of relative wall 49 b. Each surface 55 comprises a respective surface 56 in the form of an isosceles triangle and extending upwards from the respective wall 49 b; and the respective pair of triangular surfaces 57, 58 have a common first side. Each surface 57, 58 also has a second side common to surface 56 and a third side common to the associated portion 52a, 52 b.

The surfaces 55 correspond respectively to the isosceles triangle formed by the points 11b, 16a, 15a of the packaging material and to the isosceles triangle formed by the points 17a, 18a, 11 c.

Surfaces 56 correspond respectively to panels E, H of the web of packaging material; surfaces 57 and 58 of first surface 55 correspond respectively to panels G, F of the web of packaging material; and surfaces 57 and 58 of second surface 55 correspond to panels L, M, respectively.

A respective transverse surface 44 (shown in figures 1, 9, 10) projecting from relative wall 49b at the end opposite relative to relative surface 55 connects each portion 59a of wall 54a to a corresponding portion 59b of wall 54 b.

More specifically, surfaces 44 correspond to panels J and Y, respectively.

Packages 3 are then fed to unit 1 where they are folded mechanically to form respective packages 2.

With particular reference to fig. 3, each package 2 substantially comprises a parallelepiped-shaped main portion 60 corresponding to portion 49 of pack 3; and a gable portion 61, which defines the top of portion 60 and is formed by folding portion 50a of pack 3 over unit 1, as will be described in detail below.

Package 2 also comprises a bottom wall 62 defining the bottom of portion 60 and formed by folding portion 50b of pack 3 on unit 1, as will be described in detail below; and two parallel walls 63, 64; and two parallel walls 65, 66 extending perpendicularly between the walls 63, 64 of the package 2.

More specifically, the walls 63, 64, 65, 66 extend perpendicularly to the plane of the wall 62.

Walls 63 and 64 correspond to the areas of the web extending between lines 16 and 17 and between lines 15 and 18, respectively; and walls 65 and 66 correspond to the areas of the web extending between lines 15 and 16 and between lines 17 and 18, respectively.

Portion 61 comprises a wall 67 with opening means 68; and a wall 69 connected to wall 68 at top sealing strip 53.

More specifically, each of walls 67 and 69 is in the form of an isosceles trapezoid, inclined with respect to walls 63, 64, 65 and 66, converging towards top strip 53, being extended by respective walls 63 and 64 at their respective longer bases (or bases), and being joined to their respective shorter bases adjacent to top strip 53.

Walls 67 and 69 correspond to panels a and B, respectively, of the web of packaging material.

Portion 61 also comprises two transverse flaps 70, 71 folded outside the volume of package 2 available for the food product, which extend along the prolongation of respective walls 65, 66 and extend obliquely with respect to respective walls 65, 66.

More specifically, each flap 70, 71 is triangular and is formed by a respective oblique side of wall 67, by a relative end 53b, 53a of strip 53 folded onto a relative oblique side of wall 69 and by a relative edge 72 parallel to relative wall 65, 66 when folded.

More specifically, the flaps 70, 71 correspond to the panels C, D, respectively, of the web of packaging material and are folded onto the overlapping lines (superinselins) 31, 32 on the respective lines 22, 23.

Unit 1 advantageously comprises a first folding station 80, in turn comprising a plurality of first holding devices 86, each first holding device 86 holding an associated pack 3 with portion 50b, and first folding assembly 90 for folding portion 50a of pack 3 to form portion 61. Unit 1 also comprises a second folding station 81, which is located downstream of first folding station 80 in the travelling direction of packs 3, and which in turn comprises a plurality of second retaining devices 86 ', each second retaining device 86' retaining with portion 50a an associated pack 3 previously folded to form portion 61, and second folding assembly 130 for folding portion 50b of pack 3 to form wall 62.

Unit 1 also comprises a conveyor 82 for conveying packages 3 from station 80 to station 81.

Conveyor 82 moves back and forth between stations 80 and 81 and performs a forward movement to feed to station 81 packs 3 whose portions 50a have been folded to form portion 61 of packages 2, and a return movement, in which it is empty.

More specifically, each work station 80, 81 comprises a respective hub 84, 85, which is rotated about a respective axis 140 or 140' by a respective motor, not shown; and a plurality of respective conveying devices 86 or 86 ', in the example shown four each, which are angularly integral with the relative hubs 84, 85 and are moved by the relative hubs along an arcuate path about the relative axes 140 or 140'.

More specifically, the respective axes 140 or 140' about which the hubs 84, 85 rotate are parallel to each other and spaced apart from each other.

The first and second folding assemblies 90, 130 are radially external to the respective device 86 or 86 'with respect to the respective axis 140 or 140' of the associated hub 84, 85.

The devices 86 or 86 'are fixed to the relative hubs 84, 85 at angularly equidistant intervals, and each device 86 or 86' forms a respective open housing for the pack 3.

More specifically, the housing defined by each device 86 or 86 ' is delimited on said facing relative hub 84, 85 by a respective groove 87 or 87 ' for engaging the relative strip 53 and radially retaining the pack 3, and by two paddles 88 or 88 '; while two paddles 88 or 88 ', respectively, cooperate with walls 49a of pack 3, these walls 49a of pack 3 corresponding to walls 63 and 64 of package 2 to circumferentially retain pack 3 with respect to relative axis 140 or 140'.

The housings are open at opposite ends to relative hubs 84, 85, so as to allow insertion of relative pack 3 into device 86 or 86 'and/or extraction of relative pack 3 by device 86 or 86'.

With particular reference to fig. 9 and 10, each paddle 88 or 88 ' of each device 86 or 86 ' comprises, at its outer end, an edge 89 or 89 ' curved towards the other paddle of the same device, to prevent pack 3 from being thrown by centrifugation when hubs 84, 85 are rotated. More specifically, each edge 89 or 89' is toothed and hinged to the relative paddle.

Each device 86 at station 80 receives a pack 3 in a first angular position, in which pack 3 is slightly inclined with respect to a horizontal plane; feeding the package clockwise along an arc of about 90 degrees to a second angular position in which assembly 90 forms portion 61; package 3, completed by portion 61, is then fed along another arc of about 90 degrees to a third angular position, in which carrier 82 picks up package 3 and conveys it to station 81.

Along the arc between the first and third angular positions, device 86 of station 80 is set to a closed configuration in which paddle 88 cooperates with wall 49a of pack 3 to retain pack 3 within the housing defined by paddle 88 and groove 87.

In the first and third angular position, on the other hand, devices 86 of station 80 are set to an open configuration in which paddles 88 of each device 86 are separated so as to allow insertion/extraction of relative pack 3. More specifically, each pack 3 is inserted/extracted through the open end of the respective housing formed by relative device 86.

More specifically, as packs 3 are advanced, grooves 87 of each device 86 of station 80 are engaged by portion 50b of relative pack 3.

Each device 86 may advantageously be fitted with a respective adapting assembly 120 (shown in fig. 10) to reduce the size of the housing of package 3 between paddles 88 and to allow device 86 to be used with packages 3 having respective portions 49 of different sizes.

More specifically, assembly 120 comprises two bodies 121 having, on opposite sides, respective end walls and respective projections 123, wherein the end walls fit within respective recesses 122 formed along the inner edges of respective paddles 88, while respective projections 123 define between them a seat (a seat)124 engaged by strip 53 of relative pack 3.

The projection 123 is sandwiched radially between the relative axis 140 or 140 ' and the open end of the housing with respect to the relative axis 140 or 140 ', so as to retain the packs 3 having portions 49 of different sizes in the relative devices 86 or 86 '.

On the side opposite to hubs 84, 85, projection 123 is inclined with respect to axis R of pack 3 housed in device 86 or 86', so as to cooperate with relative portion 50a, 50b of pack 3.

Each body 121 is releasably secured to the associated paddle 88 or 88' by an associated threaded fastener 127.

Assembly 90 interacts, on opposite sides of axis R of each pack 3, with portions 52a, 52b of pack 3 to fold each portion 52b onto relative surface 56 and each portion 52a onto relative portion 52b to form relative flaps 70, 71 of package 2.

Referring to fig. 4 to 7, assembly 90 comprises two tools 91, 92 for folding each portion 52b onto relative surface 56 and each portion 52a onto relative portion 52b, respectively. More specifically, each portion 52b is folded onto the associated surface 56 after each portion 52b is first folded onto the associated line 40, 41.

The tools 90, 91 are hinged to respective outputs of the respective motors 105 about respective axes 141 parallel to the axis 140, and are hinged to each other about a common axis 142 parallel to the axes 141.

More specifically, tool 91 comprises a support surface 100 and two folding surfaces 101, which respectively cooperate with wall 51b to control the volume of portion 61 to be formed and with portion 52b to fold these portions onto relative surface 56.

Surfaces 100 and 101 are made to move integrally with each other in a closing movement (an approach movement), in contact with wall 51b and portion 52b respectively, and are made to move relative to each other in a folding movement in which surface 101 folds portion 52b onto relative portion 56.

More specifically, the tool 91 comprises a frame 95, which is provided, on one side, with projecting surfaces 100 and is connected, in operative relationship, to a surface 101, on the opposite side; the tool 91 further comprises two first links 93 hinged to the frame 95 and to the output of the relative motor 105; and a second link 94 hinged to the tool 92 and to the frame 95.

Frame 95 comprises a first piece 96 provided on one end and on the side opposite axis 142 with a projecting surface 100; and a second member 97 sliding with respect to member 96 and hinged to link 93 about an axis 143 parallel to axes 141, 142.

Link 93 is hinged at one end to the output of motor 105 about axis 141 and at the opposite end to frame 95 about axis 143.

The link 94 is hinged at one end to the tool 92 about an axis 142 and at the opposite end to the frame 95 about an axis 144 parallel to the axis 142.

Tool 91 also comprises two third links 99, each of which is hinged at one end to relative link 93 about axis 143 and is connected in running relationship and movably to surface 100 and to respective surface 101 at the opposite end by means of a respective connecting rod 102.

More specifically, each connecting rod 102 is L-shaped, is hinged at opposite ends to surface 100 and to a plate 107 integral with relative surface 101, and each connecting rod 102 comprises, between surface 100 and relative plate 107, an intermediate portion housed inside a ring passing through a seat formed on the end of relative link 99 relative to axis 143.

Members 96 and 97 are resiliently connected to each other by spring 98 which is compressed during the folding movement of surface 101 and which expands when surface 100 is withdrawn from wall 51 b.

The tool 92 is similar to the tool 91 and will only be described in relation to the tool 91, with the same reference numerals being used for the same or corresponding parts of the tools 91, 92.

The tool 92 differs from the tool 91 in that: the relative surface 100 cooperates with the wall 51a at the end of the relative approach movement.

Surface 101 is of the same triangular shape as portion 52a and once surface 100 cooperates with wall 51a, surface 101 folds portion 52a onto portion 52 b.

Tool 92 also includes two spaced apart links 94 and is hinged to links 94 of tool 91 about axis 142.

The folding assembly 90 also comprises two pressure members 110 (one shown in figure 8), each of which exerts a pressure on the relative surface 56 when forming the relative flap 70, 71, to facilitate the folding of the portions 52a, 52 b.

More specifically, the pressure member 110 is fitted to an actuating assembly 111 operatively connected to the motor 105 in a known manner not shown.

Assembly 111 (only partially shown in fig. 8) comprises two panels 112 which cooperate with respective walls 49b of pack 3 and from which respective pressure members 110 project; and the assembly 111 further comprises two linkages which are coupled to the motor 105 of the tool 91 with a cam mechanism, not shown.

Motor 105 and linkage 115 are connected in such a way that pressure member 110 cooperates with relative surface 56 when surface 100 of tool 91 cooperates with wall 51b, and pressure member 110 is disengaged from relative surface 56 when surface 100 of tool 91 is disengaged from wall 51 b.

More specifically, the pressure member 110 is preferably made of a deformable plastic material and is toothed. More specifically, each pressure member 110 comprises a flat surface 113 cooperating with the relative surface 56; and a surface 114 opposite to surface 113, which is inclined by relative plate 112 and cooperates with relative surfaces 57, 58 once portions 52a, 52b are folded.

The workstation 81 (fig. 1) also includes a pre-folding assembly 135 for pre-folding the portion 50 b; and a heating assembly 139 (not shown in detail) for heating and facilitating subsequent sealing of flaps 70, 71 to the inclined sides of wall 69. Each package 3 is fed through assemblies 135, 139 before assembly 130.

More specifically, each device 86' at station 81 receives a pack 3, completed by portion 61, by conveyor 82 in a first angular position, in which pack 3 is slightly inclined with respect to a horizontal plane; clockwise along an arc of about 90 degrees, feeds the package to a second angular position, in which the heating assembly 139 heats the flaps 70, 71; feeding pack 3 clockwise along another arc of about 90 degrees to a third angular position in which assembly 130 folds portion 50b of pack 3 to form portion 62; and subsequently packs 3 are fed clockwise through another approximately 90 degrees to a fourth angular position, where finished packages 2 are removed from unit 1.

Along the arc between the first and fourth angular position, devices 86 ' of station 81 are set to a closed configuration in which paddles 88 ' of each device 86 ' cooperate with wall 49a of pack 3 to retain pack 3 within the housing defined by paddles 88 ' and grooves 87 '.

In the first and fourth angular position, on the other hand, devices 86 ' of station 81 are set in an open configuration in which paddles 88 ' of each device 86 ' are separated so as to allow insertion/extraction of relative pack 3. More specifically, each pack 3 is inserted/extracted through the open end of the respective housing defined by relative device 86.

When advancing packages 3, groove 87 'of each device 86' of station 81 is engaged by portion 61 of relative package 3 formed at station 80.

Pre-folding assembly 135 folds opposite lateral portions of strip 53 of surface 44, portions 59a, 59b, and portion 50b to form two flaps 128 converging towards axis R, and folds the intermediate portion of said strip 53 and walls 54a, 54b to form a flat surface 119 (fig. 11) onto which flaps 128 are successively folded.

More specifically, each flap 128 is defined, on the side opposite to axis R, by relative surface 44 and, on the side facing axis R, by corresponding portion 59a, 59b and relative transverse portion of strip 53 passing through portion 50 b.

Surface 119 extends perpendicularly to walls 49a, 49b of pack 3 and to axis R.

More specifically, assembly 135 includes an arcuate wall 137 for folding the intermediate portion of strip 53 of portion 50b and walls 54a, 54b to form surface 119.

Assembly 135 also includes a roller 136 for exerting further pressure on the intermediate portion of strip 53 of portion 50b and walls 54a, 54 b; and two cross members (only one shown in fig. 1) 138 (located on opposite sides of the roller 136) and each forming a gap with the roller 136 through which the respective flap 128 is fed. The gap will be smaller from the first to the second angular position of the means 86 of the station 81, so as to fold the relative flap by a given angle, normally 45 degrees, towards the axis R.

More specifically, wall 137 extends along an acute angle of about 45 degrees from the first angular position of device 86 of workstation 81, while cross-member 138 extends from the end of wall 137 opposite the end at the first angular position of device 86 to the second angular position of device 86.

Assembly 139 is adjustable in position relative to axis 140' of hub 85 so as to be usable with packs 3 having different sized portions 49.

The station 81 also comprises an arc-shaped wall 125 extending between the second and third angular positions of the device 86' and cooperating with the flap 128 to hold them in the pre-folded position produced by the assembly 135.

Referring to fig. 11 and 12, assembly 130 includes a support body 131; a pressure pad 132 functionally connected to body 131 and movable radially back and forth with respect to axis 140' to fold flap 128 onto surface 119; and also two panels 133 functionally connected to body 131 and movable towards wall 49b and away from wall 49b when flaps 128 are folded, to control the volume of pack 3.

More specifically, the movement of plate 133 is linked to the movement of pressure pad 132, so that plate 133 cooperates with wall 49b when pressure pad 132 cooperates with flap 128 (fig. 12), and plate 133 disengages from wall 49b when pressure pad 132 disengages from flap 128 (fig. 11).

Referring to figures 11 and 13, at one end portion of the respective wall cooperating with relative wall 49b, each plate 133 has a sealing means 134 which cooperates with relative flap 70, 71 to seal it to the inclined side of wall 69.

Station 81 also comprises an arc-shaped wall 126 extending between the third and fourth angular positions of device 86 to keep flap 128 pressed against surface 119 when flap 128 cools.

The operation of unit 1 will now be described with reference to one pack 3, whereas pack 3 is initially supplied to station 80 of unit 1.

More specifically, inside relative device 86 of station 80 in the first angular position, packs 3 are positioned with axis R slightly inclined with respect to the horizontal plane, packs 3 being loaded with strips 53 of portion 50b inside grooves 87 and walls 49a gripped by paddles 88.

Rotation of hub 84 moves device 86 to a second angular position in which pack 3 is adjacent to assembly 90.

When hub 84 rotates, edge 89 (fig. 9 and 10) prevents pack 3 from being thrown out by centrifugation.

In the second angular position of device 86, motor 105 of tool 91 (fig. 4 to 7) moves each plate 112, by means of a cam mechanism and a linkage 115, onto relative wall 49b of pack 3 and surface 113 of each pressure member 110 onto relative surface 56.

The motor 105 then operates the tools 91, 92 to effect the respective approach movements of the respective surfaces 100.

More specifically, surface 100 of tool 91 is in contact with wall 51b of pack 3 before surface 100 of tool 92 is in contact with wall 51a of pack 3.

The motor 105 of the tool 91 is then operated to further effect the corresponding folding movement of the surface 101 of the tool 91 and thus the folding of the portion 52b onto the relative surface 56.

More specifically, portions 52b are folded with respect to wall 51b at respective lines 22, 23 and along lines 40, 41 to overlap respective panels N, Q on respective portions of respective panels E, H.

At this point, the motor 105 of the tool 92 is operated to effect a corresponding folding movement of the surface 101 of the tool 92 and, therefore, to fold the portion 52a onto the relative portion 52 b.

More specifically, portion 52a is folded with respect to wall 51a at respective lines 24, 25.

At the end of the folding movement, panels D, C are superimposed respectively on panels P, O, which in turn are superimposed respectively on panels Q, N, which are superimposed respectively on panels H, E.

Once folded, panels D, C define respective flaps 70, 71 and have respective lines 32, 31 superimposed on respective lines 23, 22.

More specifically, the approach movement starts from a starting position in which each member 97 rests on relative member 96 (fig. 4 and 5).

During the approaching movement, motor 105 rotates surfaces 100, 101 of tools 91, 92, as a whole, with respect to axis 141, by means of connecting rod 93, until surfaces 100 are seated against walls 51a, 51b of pack 3. During the approaching movement, the pieces 96, 97 of the frame 95 also move integrally with each other.

Once the approaching movement is completed, the motor 105, by means of the link 93, causes the link 99 and the piece 97 of the tools 91, 92 to rotate further with respect to the relative axes 143, 141, thus compressing the springs 98 of the tools 91, 92.

The rotation of the link 99 causes the connecting rods 102 of the tools 91, 92 to rotate with respect to the relative surfaces 100 and, consequently, by means of the plates 107, the pairs of surfaces 101 with respect to the relative surfaces 100.

At the end of the folding movement, the ends 53a, 53b are slightly detached from the inclined sides of the wall 69 and the surface 55 is slightly detached from the surface 56, so that heating and sealing can be carried out at the station 81.

Once the folding movement is completed, motor 105 is operated in reverse, first member 110 is extracted from surface 56, then surface 101 is extracted from flaps 70, 71 and finally surface 100 is extracted from walls 67, 69.

During the above-mentioned extraction movement, the previously compressed spring 98 expands, restoring the relative element 97 to the position of seating against the relative element 96.

At this point, hub 84 moves, by means of device 86, the completed packet 3 of portion 61 by another 90 degrees in a clockwise direction, into a third angular position in which carrier 82 picks up the packet and conveys it to station 81.

One of devices 86' of station 81 in the first angular position moves a pack 3, completed by portion 61, away from conveyor 82.

More specifically, inside device 86 'of station 81 in the first angular position, packs 3, in which portion 61 has been completed and with axis R slightly inclined with respect to the horizontal plane, are housed inside the casing defined by relative device 86', with strip 53 of portion 61 already formed previously inside groove 87 ', and wall 49a gripped by paddle 88'.

As hub 85 rotates about axis 140 ', device 86' feeds pack 3, with portion 61 already completed, from the first angular position to the second angular position, so that portion 50b is in contact with assembly 135, which is pre-folded.

More specifically, wall 137 exerts pressure on the middle portion of strip 53 and on walls 54a, 54b of portion 50b to form surface 119, which surface 119 is coplanar with wall 62.

Due to the shape of the gap defined between them, roller 136 and cross-member 138 fold the end portions of strip 53 of surface 44, portions 59a, 59b, and portion 50b, so that flaps 128 converge with respect to axis R of pack 3 and converge at an angle of about 45 degrees with respect to axis R (fig. 11).

Once device 86 has brought package 3, with portion 61 already completed and portion 50b already folded as described above, to the second angular position, assembly 139 heats flaps 70, 71 in a known manner to accelerate the subsequent process of sealing flaps 70, 71 to the inclined sides of wall 69.

As hub 85 rotates, device 86' will cause the pack 3, with portion 61 completed, to move to a third angular position in which pressure pad 132 (fig. 11 and 12) folds portions 59a, 59b onto surface 119 to complete the folding of wall 62, and sealing device 134 seals flaps 70, 71 onto the inclined sides of wall 69.

More specifically, during operation of pressure pad 132, plate 133 cooperates with wall 49b to control the volume of pack 3.

In the third angular position, another known heating device (not shown) heats flap 128 and another known sealing device (not shown) seals flap 128 to surface 119.

The relative device 86' then feeds the finished packages 2 formed to a fourth angular position, in which they are conveyed by unit 1 to the packaging machine station downstream.

Each device 86 ' can be fitted with a respective assembly 120 ' in order to reduce the volume between paddles 88 ' and thus to produce packages 2 from packs 3 having portions 49 of different sizes.

With assemblies 120 or 120 '(fig. 10), package 3 can be loaded with one of strips 53 inside seat 124 and with each wall 49a cooperating with the end portion of relative paddle 88 or 88' on the side of relative body 121 opposite hubs 84, 85 and with the portion of relative edge 89 extending between the end portion on the side opposite hubs 84, 85.

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

In particular, by producing packages 2 with identical portions 61 from packs 3 with portions 49 of different sizes, by modifying device 86 or 86 'or by using assemblies 120 or 120', unit 1, a great flexibility is obtained.

More specifically, the use of a respective device 86 or 86 'for each size of portion 49 (with recesses 87 or 87' at a given distance from relative axis 140 or 140 ') allows packages 3 with portions 49 of different sizes to interact with assemblies 90, 130 in a given angular position of device 86 or 86'.

Alternatively, a respective assembly 120 or 120 'may be used for the size of each portion 49, so as to reduce the volume of the housing of pack 3, while allowing pack 3 to interact with assemblies 90, 130 in a given angular position of device 86 or 86'.

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

Claims (9)

1. A folding unit (1) for producing sealed packages (2) of pourable food products from respective packages (3), each package having a main portion (49) folded into a desired shape and opposite end portions (50a, 50b) folded to form respective folded ends (61, 62) of a relative final package (2);

said folding unit (1) being characterized in that it comprises:

-a first folding station (80) in turn comprising first retaining means (86, 87, 88) for fixing each of said packages (3) by means of the relative first end portion (50 b); and first folding means (90) for folding an associated second end portion (50a) of said pack (3); and

-a second folding station (81) located downstream of said first folding station (80) in the travelling direction of said packs (3), and which in turn comprises second retaining means (86 ', 87 ', 88 ') for securing each of said packs (3) by the relative folded second end portion (50a), and second folding means (130) for folding the relative first end portion (50 b).

2. A unit as claimed in claim 1, characterized in that it comprises conveying means (82) for conveying said packs (3) from said first folding station (80) to said second folding station (81).

3. A unit as claimed in claim 1 or 2, wherein said first holding means (86, 87, 88) of said first folding station (80) and said first folding means (90) are rotated with respect to each other about a first axis (140); and wherein said first retaining means (86, 87, 88) are arranged radially internal with respect to said first folding means (90) with respect to said first axis (140); and/or

-said second holding means (86 ', 87', 88 ') of said second folding station (81), and said second folding means (130) rotate with respect to each other about a second axis (140') parallel to and spaced apart from said first axis (140); and wherein said second retaining means (86 ', 87', 88 ') are arranged radially inside with respect to said second folding means (130) with respect to said second axis (140').

4. A unit as claimed in claim 3, wherein said first retaining means (86, 87, 88) define respective housings for said packages (3); the housing rotates about the first axis (140) and is open at an outer peripheral end in a radial direction with respect to the first axis (140); and

said second retaining means (86 ', 87 ', 88 ') also defining respective housings for said packages (3); the housing rotates about the second axis (140 ') and is open at an outer peripheral end in a radial direction with respect to the second axis (140').

5. A unit as claimed in claim 4, wherein said first retaining means (86, 87, 88) comprise, at the ends radially directed towards the respective said first axis (140): a first recess (87) for engagement with the pack (3), and two first pieces (88), each of which cooperates with a respective wall (49a) of the pack (3); the respective first recess and the first piece define a respective housing; and

said second retaining means (86 ', 87', 88 ') comprise, at an end in a radial direction towards the respective second axis (140'): a second recess (87 ') for engagement with said pack (3), and two second pieces (88'), each of which cooperates with a respective wall (49a) of said pack (3); the respective second recess and the second piece also define a respective housing.

6. A unit as claimed in claim 5, characterized in that it comprises adapting means (120) cooperating with said first retaining means (86, 87, 88) and said second retaining means (86 ', 87 ', 88 ') to adjust said housing so as to be able to retain packages (3) of different characteristic sizes.

7. The unit according to claim 6, characterized in that said adapting means (120) comprise at least two bodies, each of which cooperates with a respective said first or second piece and which define a seat (124) for engaging with said package (3) and being sandwiched between the respective said first or second recess and said open end of said casing.

8. A unit as claimed in claim 4, characterized in that said first retaining means (86, 87, 88) and said second retaining means (86 ', 87 ', 88 ') each comprise at least one tooth projecting inwardly from said housing, said tooth being intended to prevent said pack (3) from being thrown away by centrifugal force.

9. A unit as claimed in claim 4, characterized in that it comprises adapting means (120) cooperating with said first retaining means (86, 87, 88) and said second retaining means (86 ', 87 ', 88 ') to adjust said housing so as to be able to retain packages (3) of different characteristic sizes.