US20050229546A1

US20050229546A1 - Method and system for packaging rolls of products

Info

Publication number: US20050229546A1
Application number: US11/107,592
Authority: US
Inventors: Gilberto Poli; Matteo Pattuelli
Original assignee: TMC SpA
Current assignee: TMC SpA
Priority date: 2004-04-20
Filing date: 2005-04-15
Publication date: 2005-10-20
Also published as: CN1689915A; ITBO20040232A1

Abstract

A method and system for packaging rolls of products, in particular rolls of toilet and/or kitchen paper, in which a wrapping sheet is wrapped in a “U” shape around a group of products so that its two end flaps project from the group, each of the end flaps then being folded in an “L” shape so that one portion adheres to the group and the remaining end portion extends transversally to the group and adheres, at the point where they meet, to the end portion of the other flap; the flaps then being sealed to one another at their end portions to form a tubular wrapper.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a method and system for packaging rolls of products, in particular rolls of toilet and/or kitchen paper.
At present, in the automatic systems which package the above-mentioned rolls, the rolls are grouped in one or more layers, each consisting of two or more rolls lined up in a row or in rows and columns, and the rolls are sent to a feed station downstream of which there is a packaging unit, designed to wrap the group of rolls with a wrapping sheet made of heat-sealable material, normally transparent polypropylene, and to stabilize the wrapper obtained in this way.
In a known system configuration, the roll feed station and the packaging unit are arranged one after the other, the former below the latter and with a horizontal elevator plate between them, which receives the rolls in the feed station and transfers them to the packaging unit.
There are normally two vertical walls linked to the elevator plate, to laterally delimit the size, that is to say the format, of the group of rolls. These vertical walls allow the format to be held stable, in particular when the format includes two or more layers on top of one another.
The packaging unit normally comprises a chain conveyor or conveyor belt, which is closed in a loop and fitted with U-shaped compartments (formed by feed teeth), designed to hold respective groups of rolls. The conveyor is driven with a stepping motion and is located above the feed station so that, with each dwell, it stops with one of its compartments with the opening opposite the elevator plate.
Connected to the packaging unit there is a wrapping sheet feed line which, after each conveyor stop, feeds a wrapping sheet to the compartment located opposite the elevator plate. The wrapping sheet is fed in such a way that it closes the compartment opening, so that, when the elevator plate is subsequently raised, the sheet is intercepted by the group of rolls and is forced into the compartment by the rolls.
Insertion of the group of rolls in the compartment folds the wrapping sheet into a U shape around the group, then two end flaps of the wrapping sheet project from the compartment.
According to a known packaging method, a first of the two flaps is folded at a right angle on the group of rolls by a first folder on the packaging unit, then the second of the two flaps is folded at a right angle on the first flap by a second folder on the packaging unit. The zone where the flaps overlap is then subjected to a wrapper stabilizing operation which consists in sealing the flaps to one another further downstream than the folding zone (that is to say, as the compartments are fed forwards with a stepping motion).
This widespread method has the disadvantage of being rather complicated and requiring considerable implementation times for packaging, with obvious negative effects on the system production costs and on system productivity. Moreover, the method described above may often cause unwanted sealing of the first flap on the group of rolls. In other words, after an unwanted overtemperature in the sealing means (for example, due to heat inertias), the fist flap often melts, sticking to one or more rolls or, in some types of packs with outer packaging, sticking to the film of the inner packs.

SUMMARY OF THE INVENTION

An aim of the present invention is to provide a method for packaging rolls of products, in particular rolls of toilet and/or kitchen paper, which is simple and requires relatively contained packaging times.
Another aim of the present invention is to provide a method for packaging rolls of products, in particular rolls of toilet and/or kitchen paper, which can be implemented by a relatively simple and economical system.
Yet another aim of the present invention is to provide a method for packaging rolls of products, in particular rolls of toilet and/or kitchen paper, which guarantees that the products are free of the above-mentioned defect.
Accordingly, the present invention achieves said aim with a method and system for packaging rolls of products, in particular rolls of toilet and/or kitchen paper, in which a wrapping sheet is wrapped in a “U” around a group of products so that its end flaps project from the group, each end flap then being folded into an “L” shape so that one portion of it adheres to the group and its remaining end portion extends transversally to the group and adheres, where they meet, to the end portion of the other flap. Finally, the flaps are sealed to one another at their end portions to form a tubular wrapper.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention, without limiting the scope of the inventive concept, are described below with reference to the accompanying drawings, in which:
FIGS. 1 and 2 are schematic illustrations at respective moments of operation, of an embodiment of the packaging system according to the present invention;
FIG. 3 is a schematic illustration of a sequence of packaging steps performed by the system illustrated in FIGS. 1 and 2;
FIG. 4 is a view of a detail of the system illustrated in FIGS. 1 and 2;
FIG. 5 is a view of an alternative embodiment of the detail illustrated in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, the numeral 1 denotes as a whole a system for packaging rolls of products, in particular rolls 2 of toilet and/or kitchen paper.
In the system 1, the rolls 2 are grouped, in the known way not illustrated, in one or more layers, each consisting of two or more rolls 2 lined up in a row or in rows and columns, and the rolls are sent to a feed station 3. In particular, in the embodiment illustrated, without limiting the scope of the invention, the rolls 2 are arranged in parallelepiped groups 4 in three layers 5, 6 and 7.
Downstream of the feed station 3, the system 1 comprises a packaging unit 8, designed to wrap each group 4 with a wrapping sheet 9 and to stabilize the wrapper 10 obtained in this way.
The wrapping sheet 9 is made of a heat-sealable material, preferably transparent polypropylene.
The feed station 3 and the packaging unit 8 are arranged one after the other, the former below the latter, with transfer means between them consisting of a horizontal elevator device 11 which is also part of the system 1.
Linked to the elevator device 11, which receives the rolls 2 in the feed station 3 (broken line in FIG. 1) and transfers them to the packaging unit 8 (continuous line in FIG. 1), there are two vertical walls 12 which laterally delimit the size, that is to say, the format, of the groups 4 of rolls 2.
In the embodiment illustrated, the elevator device 11 comprises a central elevator plate 13 and two side elevator plates 14, located on opposite sides of the central plate 13.
The side plates 14 are horizontal and coplanar, and are secured to one another by a lower bridge 15 to which a first vertical movement part 16 is connected.
The central plate 13 is also horizontal and is connected to a second vertical movement part 17, which is independent of the first vertical movement part 16, allowing the central plate 13 to move to a position in which it is coplanar with the side plates 14 (dashed line in FIG. 1) and positions in which it is raised relative to the side plates (continuous line in FIG. 1 and FIG. 2).
The packaging unit 8 comprises a conveyor 18, equipped with a chain and/or belt 19, closed in a loop over two pulleys 20 one of which is a driving pulley, and a plurality of feed units or compartments 21 having an inverted “U” shape and of the correct size to hold respective groups 4 of rolls 2 without play.
The compartments 21 are evenly distributed along a lower transfer branch of the chain/belt 19 and each has a bottom wall 22, formed by a fixed horizontal plate 23 located below the chain/belt 19, and two groups of teeth forming mobile side walls 24, which are fixed at a right angle to the chain/belt 19 and run comb-style relative to the plate 23 along the above-mentioned lower transfer branch.
The pulleys 20 are positioned at the same height and have the same diameter, so that the lower transfer branch of the chain/belt 19 is horizontal and, as a result, the walls 24 are vertical. For each compartment 21, the latter form an opening 25 which is opposite the bottom wall 22.
The conveyor 18 is motor-driven, with a stepping motion, and is located above the feed station 3, so that with each dwell, one of its compartments 21 stops with its opening 25 opposite the plates 13 and 14 and with the walls 24 aligned with the walls 12 and separated from the latter to form respective rectangular gaps 26. In other words, after each conveyor 18 chain/belt 19 feed step, a compartment 21 stops so that it is vertically aligned with a group 4 of rolls 2 located in the feed station 3, and the compartment 21 is angled in such a way that its opening 25 is opposite and vertically aligned with the group 4.
Connected to the packaging unit 8 there is a wrapping sheet 9 feed line (not illustrated), which, after each conveyor 18 stop, feeds a wrapping sheet 9 to the compartment 21 located opposite the plates 13 and 14. In particular, the wrapping sheet 9 is fed according to known methods in a direction at a right angle to the plane of the sheet in FIG. 1 so as to close the compartment 21 opening 25 and extend in a stretched out position through the two gaps 26.
The packaging unit 8 also comprises two folders 27 consisting of respective plates with opposite horizontal motion along a shared direction D and through the gaps 26. Each folder 27 is hinged to a connecting rod 28, in turn hinged to a motor-driven crank 29. The action of the folders 27 on each sheet 9, as is explained in more detail below, forms a tubular wrapper 30, whose subsequent folding, by further folders of the known type and not illustrated, produces the above-mentioned wrapper 10.
The tubular wrapper 30 is stabilized by a packaging unit 8 stabilizing device 31.
The device 31, as illustrated in FIG. 4, is incorporated in the folders 27 to allow outer closure of the group 4 of products at the final step of flap 38 folding and the relative stable connection of the end portions 39 of the flaps 38 of the sheet 9 of film to one another when the group 4 is still above the lifting plates 13 and 14.
This device 31 may comprise a sealing plate 32 housed in a cavity in the head 33 of a first folder 27 of the two. The head 33 is transversal, in particular at a right angle, to the direction D.
The plate 32 gives onto the head 33 at the edge of the latter, has low heat inertia and is preferably thermally insulated from the folder 27. The plate 32, in its simplest form, consists of an electrical resistor of a circuit controlled by a control unit 34. However, in an alternative embodiment, not illustrated, the plate 32 may be heated by electromagnetic induction.
In addition to the plate 32, the device 31 comprises a pad 35, for example made of silicone rubber, which is slidably housed in a cavity in the head 36 of the second folder 27 of the two. In its preferred geometric configuration the head 36 is parallel with the head 33.
Between the pad 35 and the bottom of the cavity in the head 36 there may be a spring 37, which makes the pad 35 elastically yielding in the direction D in which the folders 27 slide.
In the alternative embodiment of the device 31 illustrated in FIG. 5, the spring 37 may be absent and the elastic action of the pad 35 is guaranteed only by the elastic properties of the silicone rubber. Moreover, the tops of the heads 33 and 36 of the folders 27 may have a projection 41 and, respectively, a recess 42, which, in contact with one another, form a male-female connection. The function of the projection 41 is to hold the respective flap 38 far enough from the plate 32 during the initial step of bringing the folders 27 together. This avoids the risk of overheating the flap 38 before sealing, and so prevents the flap 38 from puckering and causing an incorrect join, that is to say, misalignment of the end portions or strips 39.
As illustrated in FIG. 1, the two cranks 29 may be independently motor-driven by two motors 29 a and 29 b schematically illustrated with a block.
In an alternative embodiment not illustrated, the lifting plates 13 and 14 may be substituted with a single plate without the solution disclosed losing any of its originality.
In another alternative embodiment not illustrated, hot-melt glue may be applied on the strips 39 of each sheet 9, and the holt-melt glue is softened by applying heat, consequently gluing the strips 39 together, by means of the stabilizing device 31 described above. In this case, the sheet 9 is not necessarily made of a heat-sealable material, but may, for example, be made of paper.
The following is a description of the method of operation of the system 1 described above starting from a moment in which a group 4 of rolls 2 is located in the feed station 3 (broken line in FIG. 1), a compartment 21 is dwelling with its walls 24 aligned with the walls 12, the plates 13 and 14 are coplanar with one another in a lowered position supporting the group 4 of rolls 2 (dashed line in FIG. 1), and a wrapping sheet 9 closes the opening 25 of the compartment 21 and extends in a stretched out position through the two gaps 26 (see also FIG. 3).
A subsequent simultaneous movement of the plates 13 and 14, by the respective movement parts 17 and 16, causes the group 4 to intercept the sheet 9 and push it, at a right angle to the above-mentioned direction D, into the compartment 21. This operation, which ends when the group 4 reaches the bottom wall 22 of the compartment 21, folds the sheet 9 in a “U” shape around the group 4 and leaves two end flaps 38 of the sheet 9 outside the walls 24 extending at a right angle to the direction D. The initial position of the sheet 9 is such that it guarantees that the two flaps 38 are substantially the same length (again see FIG. 3).
At this point, the plates 14 are lowered by the movement part 16, whilst the plate 13 is held in contact with the group 4 (continuous line in FIG. 1) to keep the group 4 in position more securely.
The subsequent movement of the folders 27 towards one another causes simultaneous and symmetrical folding of the flaps 38 on the group 4. Before the folders 27 reach the plate 13, the latter is lowered by the movement part 17.
When the folders 27 reach the end of their stroke (FIG. 2) each flap 38 is folded in an “L” shape and two end portions or strips 39 of the flaps 38 are brought together and stably gripped by the heads 33 and 36 which act like the jaws of a gripper. Therefore, after being folded on the group 4, the flaps 38 each have a portion 43 adhering to the group 4 and a remaining portion, formed by the strip 39, extending transversally to the group 4 and adhering, where they meet, to the strip 39 of the other flap 38.
Said join, as illustrated in FIG. 3, produces a portion 40 of the tubular wrapper 30 which is stabilized by the device 31 by applying heat as it grips the strips 39.
The elastic action of the pad 35 on one hand guarantees correct pressure on the strips 39 while they are sealed, and on the other hand allows the strips 39 to escape the grip of the folders 27 if there are errors in synchronization between the movement of the cranks 29 and of the conveyor 18.
With regard to this, it should be noticed that the simultaneous and symmetrical movement of the folders 27 in the above-mentioned direction D is achieved by means of the two motors 29 a and 29 b, which drive the two cranks 29.
It would be possible, without limiting the scope of the invention, to use a single motor 29 c for synchronized movement of the cranks 29 (see broken line in FIG. 1).
A method and the relative system obtained in this way achieve the preset aims thanks to simplification of the sealing step, which is basically carried out during the step of folding the flaps of film.
This combined lower flap folding-sealing speeds up machine productivity even more, reduces the dimensions, eliminating a sealing station downstream of the packaging station, with evident economic advantages.
In addition, sealing is safer since it takes place far from the rolls or from the film of other packs grouped together, preventing contact between products and heated operating elements.
The invention described may be subject to modifications and variations, or various combinations of the alternative embodiments described above, without thereby departing from the scope of the inventive concept. Moreover, all of the details of the invention may be substituted by technically equivalent elements.

LIST OF REFERENCE CHARACTERS

- 1 Packaging system 23 Plate
- 2 Rolls 24 Compartment walls
- 3 Feed station 25 Compartment opening
- 4 Groups of rolls 26 Gaps
- 5 Layer of rolls 27 Folders
- 6 Layer of rolls 28 Connecting rod
- 7 Layer of rolls 29 Crank
- 8 Packaging unit 30 Tubular wrapper
- 9 Wrapping sheet 31 Stabilizing device
- 10 Wrapper 32 Sealing plate
- 11 Elevator device 33 Folder head
- 12 Vertical walls 34 Control unit
- 13 Elevator plate 35 Pad
- 14 Elevator plates 36 Folder head
- 15 Bridge 37 Spring
- 16 Movement part 38 Wrapping sheet flaps
- 17 Movement part 39 End strips of flaps
- 18 Conveyor 40 Portion of tubular wrapper
- 19 Chain 41 Projection
- 20 Pulleys 42 Recess
- 21 Compartments 43 portion of flap
- 22 Compartment walls D direction

Claims

1. A method for packaging rolls of products, comprising the steps of:

aligning a group of rolls of products with an inverted U-shaped feed unit or compartment of a packaging unit, the compartment being angled with its opening opposite the group of rolls of products;

placing a wrapping sheet in a predetermined position between the group of rolls of products and the compartment opening;

pushing the group of rolls of products into the compartment so that it intercepts the wrapping sheet, folding the wrapping sheet in a “U” shape around the group of rolls of products and inside the compartment, the wrapping sheet, once folded into a “U” shape, having its two end flaps projecting from the compartment;

folding said flaps over the group of rolls of products to form a tubular wrapper; and

stabilizing the tubular wrapper by fixing the flaps to one another;

wherein the step of folding the flaps involves substantially folding each flap into an “L” shape so that one portion of the flap adheres to the group of rolls of products and its remaining end portion extends transversally to the group and adheres, at the point where they meet, to the end portion of the other flap; the step of stabilizing the tubular wrapper involving stably fixing the flaps to one another at the end portions and at the end of the folding step.

2. The method according to claim 1, wherein the stabilizing step is carried out by applying heat to the end portions.

3. The method according to claim 2, wherein the stabilizing step consists of sealing the end portions to one another.

4. The method according to claim 1, wherein the step of folding the flaps involves simultaneously and symmetrically folding both flaps.

5. A system for packaging rolls of products, comprising a packaging unit and transfer means for feeding to the packaging unit groups of rolls of products with respective wrapping sheets; the packaging unit comprising a conveyor with compartments, each having an inverted “U” shape and designed to receive, from the transfer means, a group of rolls of products with the relative wrapping sheet folded in a “U” around the group and with its two end flaps projecting from the compartment; the packaging unit also comprising folding means for folding the flaps over the group to form a tubular wrapper, and means for stabilizing the tubular wrapper by fixing the flaps to one another; wherein the folding means comprise two folding plates mobile in a direction at a right angle to the flaps, having respective heads transversal to said direction, and forming, with said heads, two jaws designed to bring together and stably grip together two respective end strips of the flaps.

6. The system according to claim 5, wherein the stabilizing means are integrated in the heads for fixing the flaps to one another at the end portions.

7. The system according to claim 6, wherein the stabilizing means are designed to apply heat to the end portions.

8. The system according to claim 7, wherein the stabilizing means are designed to seal the end portions to one another.

9. The system according to claim 5, comprising drive means for imparting to the folding plates opposite simultaneous and symmetrical movements in said direction.

10. The system according to claim 9, wherein the drive means comprise, for each folding plate, a connecting rod hinged to the folding plate and a crank hinged to the connecting rod.

11. The system according to claim 5, wherein the tubular wrapper stabilizing means comprise a sealing plate, housed in the head of one of the folding plates, and a pad, housed in the head of the other folding plate.

12. The system according to claim 11, wherein the sealing plate is an electrical resistor.

13. The system according to claim 11, wherein the pad is elastically yielding in said direction.

14. The system according to claim 13, wherein the pad is made of silicone rubber.

15. The system according to claim 13, wherein the pad is housed in the head of the respective folding plate with a spring that is elastically yielding in said direction inserted between the pad and the plate.

16. The system according to claim 5, wherein the heads are at a right angle to the direction.

17. The system according to claim 11, wherein, upon making contact with one another, the heads form a male-female connection.

18. The system according to claim 17, wherein, of the heads, the head housing the sealing plate has a projection, whilst the head housing the pad has a recess; the projection and the recess, upon making contact with one another, forming a male-female connection.

19. The system according to claim 10, wherein each crank is driven by a relative motor.

20. The system according to claim 10, wherein the cranks are driven by a single central motor.