WO2012032377A1

WO2012032377A1 - System for manufacturing paper bags

Info

Publication number: WO2012032377A1
Application number: PCT/IB2010/054128
Authority: WO
Inventors: Stefano Giacometti; Fernando Giacometti
Original assignee: J.W.T. Snc Di Giacometti Stefano & Zanon Walter
Priority date: 2010-09-10
Filing date: 2010-09-14
Publication date: 2012-03-15
Also published as: ITPD20100268A1

Abstract

The invention is a system for the mass production of paper shoppers or bags (B)5 comprising a station (2) for feeding at least one continuous paper strip (N) along a longitudinal advance direction (L), and at least one station (3) where the continuous strip (N) is folded along a longitudinal folding line (L'). The folding along the latter line is carried out in such a way that at least one pair of longitudinal laps (S', S") substantially face each other, wherein said longitudinal laps (S', S") define corresponding opposite sides (P', P") of the bags (B). In particular, the folding station (3) comprises guide means (6) for the strip (N) that are suited to move both the longitudinal laps (S', S") from a substantially horizontal position to a substantially opposite vertical position, thus forming the continuous bottom of the bag.

Description

SYSTEM FOR MANUFACTURING PAPER BAGS

Description

Field of application of the invention

The present invention can be generally applied in the sector of paper shoppers and bags, and in particular it concerns a system for manufacturing bags of the type described in the preamble of claim 1.

State of the art

The patent document WO2009/122451 discloses a machine for making paper bags with continuous bottom, comprising a station where a continuous paper strip is unwound from a roll. The roll is constrained so as to turn around a horizontal rotation axis. The machine also includes the following: a creasing station suited to allow the paper to be successively folded; a station where vinyl glue is spread along the edges of the bag to be glued and in predetermined areas for the successive glueing of the handles; a station where the paper is folded along its advance direction; a station where the edges and the handles are glued by compression; a station where the bags are cut. In particular, all the operations are carried out with the paper strip in a substantially horizontal position. This feature makes it necessary for the longitudinal folding station to raise one edge of the continuous strip and rotate it by 180° until bringing it on the corresponding opposite edge.

This last operation in which the strip is folded longitudinally with a 180° rotation poses the drawback that it causes the paper to be considerably deformed, with the double negative consequence that the folding must be carried out in a relatively long time and large space along the paper advance direction. Said negative consequences cause a first practical drawback which lies in that they limit the maximum speed at which it is possible to make the paper strip advance in order to carry out the folding operation, thus reducing the number of bags that can be manufactured per unit of time.

Description of the invention

A primary object of the present invention is to overcome the drawbacks described above, carrying out a system that allows a relatively high production speed to be obtained.

An additional object of the invention is to carry out a system that generates a relatively low mechanical stress on the paper strip during the folding operation. A further object of the invention is to carry out a system that allows a safe and reliable folding operation to be carried out on the paper strip.

These objects, and others that will be highlighted in greater detail below, are achieved, according to claim 1, by a system for the mass production of paper shoppers or bags, comprising a station for feeding at least one continuous paper strip along a longitudinal advance direction, and at least one station where the continuous strip is folded along a longitudinal folding line. In said station at least one pair of longitudinal laps are arranged so as to substantially face each other, said laps defining corresponding opposite sides of the bags. In particular, the folding station comprises strip guide means that are suited to move both the longitudinal laps from a substantially horizontal position to a substantially vertical position.

Thanks to this particular configuration it will be possible to reduce the degree of deformation produced on the paper during the folding stage, with the double advantage of increasing the production speed and reducing the overall dimensions along the strip advance direction, while at the same time avoiding any contact with the parts where the glue has already been spread.

The bags obtained have a continuous bottom, folded like a bellows, which can be obtained only thanks to the new configuration of the system described and claimed here below.

The system that processes the strip by folding it in a substantially vertical position, in fact, ensures high production speed and furthermore guarantees high quality of the folding and glueing operations, and therefore of the finished product.

In fact, a system manufacturing the same product but working only horizontally would not only have a much lower hourly output, but also be unable to guarantee such an optimal result, due to inevitable structural time limits, which can be experimentally confirmed and are difficult to overcome.

Brief description of the drawings

The characteristics of the new system for the mass production of paper shoppers or bags will be better illustrated in the following description with reference to the drawings, attached by way of non-limiting examples.

Figure 1 shows a schematic view of an example of embodiment of the system carried out according to the invention, while Figure la shows just a detail of the same;

Figure 2 is a side view of the system shown in Figure 1, while Figure 2a shows just a detail of the same;

Figures 3a, 3b and 3c respectively show a view of a closed bag that can be manufactured with the system shown in Figure 1, a view of the open upper side Bs of a bag and a view of the open lower side Bi of a bag, where the glueing areas are hatched; Figure 4 shows a view of a section of the paper strip during an intermediate stage of the process carried out with the system of Figure 1;

Figure 5 shows a view of a section of the strip in a final stage of the process carried out with the system of Figure 1.

Detailed description of a preferred embodiment of the invention

The system is described with particular reference to the enclosed figures, the reference numbers used in the description and in the claims are used to improve the intelligibility of the invention and do not constitute a limitation to the claimed scope of protection.

The system for the mass production of paper shoppers or bags is indicated as a whole by 1. The system 1 comprises a station 2 for feeding a continuous paper strip N along a longitudinal advance direction L, and at least one station 3 where the continuous strip N is folded. Folding is carried out along a longitudinal folding line L' so that at least one pair of longitudinal laps S', S" substantially face each other. At the end of the production process, the latter define corresponding opposite sides P', P" of the bags B, while the longitudinal folding line L' defines the bottom of the bags B. If necessary, the system 1 may comprise a creasing station 4 suited to carry out one or more longitudinal and if necessary transversal creases, in order to improve the successive folding stage. The system 1 may also comprise a station 5 for the application of the handles M that are permanently fixed to each bag B during a successive compression stage, and an upper glueing device 5' for spreading glue on the upper side of the strip N, in the areas that will be successively glued by compression.

A special characteristic of the invention lies in that the folding station 3 comprises means 6 suited to guide the strip N and to match said longitudinal laps S', S", rotating them by 90° from a substantially horizontal position to a substantially vertical position, and keeping them parallel to the longitudinal advance direction L.

In greater detail, the guide means 6 of the folding station 3 may comprise one or more constrained cylinders 7 turning around corresponding substantially vertical rotation axes. Each vertical cylinder 7 may have a side wall 8 suited to interact with the longitudinal laps S', S" of the strip N, in order to guide them and if necessary bring them to the vertical position. The guide means 6 may comprise one pair of constrained vertical cylinders 7 having their rotation axes substantially parallel and spaced of a distance substantially equal to the sum of their radii. In this way, the side walls 8 may also exert a limited compression on the longitudinal laps S\ S", increasing the effectiveness of the downward guiding action of the vertical cylinders 7.

The guide means 6 of the folding station 3 may comprise at least one slide pad 9, or another device suitable for folding, having a surface 10 shaped in such a way that the strip N, sliding on it, is at least partially folded at the level of longitudinal folding lines L", L'", as shown in Figures 3b, 4.

The guide means 6, furthermore, may also comprise at least one constrained disc 11 turning around a rotation axis that is substantially horizontal and transversal to the advance direction L. The disc 11 may have a peripheral wall 12 in contact with the strip N positioned at the level of the longitudinal folding line L' between the longitudinal laps S\ S".

Between the guide means 6 there may be at least one substantially horizontal supporting and tensioning edge or roller 13 positioned upstream and at a different height with respect to the slide pad 9 and the constrained disc 11. In particular, the difference in height between the latter and the horizontal edge 13 exerts on the strip N a force having a component that is orthogonal to the strip itself, which makes it possible to fold the longitudinal laps S\ S" from their initial horizontal position to the substantially vertical final position. In this way, each lap S', S" is substantially rotated by 90° and there is no 180° rotation as in the current state of the art. These two simultaneous operations, each substantially by 90°, make it possible to reduce the folding times and the possible deformations of the paper, and therefore to increase the speed of the strip N and the output. The horizontal edge or roller 13 can be substantially integral with the system 1 or can be a constrained roller turning around a substantially horizontal axis.

In the preferred embodiment of the invention, said horizontal edge or roller 13 is in a higher sliding position compared to the sliding position of said slide pad 9 and said constrained disc 11, wherein said constrained disc 11 rests on the lower side of the strip N, which will coincide with the external surface of the bag B, forming the bottom and the bellows of the bag B.

In the preferred embodiment of the invention, downstream of said horizontal edge or roller 13 and upstream of said constrained disc 11, the new system comprises a further lower glueing device 5" for spreading the glue on the lower side of the strip N, at the level of the transversal joints as indicated in Figure 3c, in order to glue the bottom of the bag.

In a preferred embodiment of the invention the slide pad 9 is positioned upstream of the constrained disc 11. In this way, the pad 9 exerts a first deforming and partially folding action on the strip N, while the disc 11, having contained thickness in the transversal direction, makes it possible to improve the fold along the crease previously made on the strip N between the two longitudinal laps S', As shown in Figure 2, the folding station 3 may comprise one or more moving guides 14, 14' suited to support and move the slide pad 9, the constrained disc 11 and the vertical cylinders 7. The moving guides can be substantially horizontal 14 or substantially vertical 14'.

As shown in Figures 1 and 2, the system 1 according to the invention may have, downstream of the folding station 3, at least one station 15 for the compression of the longitudinal laps S', S" that substantially face each other. The compression station 15 may be provided with a plurality of constrained compression rollers 16 turning around substantially vertical axes, so as to compress the areas to be glued and make them adhere to each other without changing the substantially vertical orientation of the longitudinal laps S', S".

Said compression rollers 16 furthermore drive said folded strip N along said longitudinal advance direction L.

Furthermore, the system 1 may have, downstream of the compression station 15, at least one station 17 for cutting the individual bags B from the continuous strip N. The cutting station 17 may be provided with one or more moving blades 18 positioned in a substantially vertical direction to carry out the cutting operation without changing the substantially vertical orientation of the longitudinal laps S\ S".

As shown in Figure 5, said cutting station 17 carries out the transversal cut 171 between the adjacent bags B.

Finally, the system comprises at least one overturning device or conveyor 19 that overturns the finished bags B from the substantially vertical position to a substantially horizontal position for the successive packaging and storage operations.

The above clearly shows that the system 1 carried out according to the invention achieves the set objects, and in particular makes it possible to obtain high production speeds and relatively contained overall longitudinal dimensions.

Therefore, with reference to the above description and the attached drawings, the following claims are expressed.

Claims

C L A I M S

1. System for the mass production of paper shoppers or bags (B), comprising a station (2) for feeding at least one continuous paper strip (N) along a longitudinal advance direction (L), and at least one station (3) where the continuous strip (N) is folded along at least one longitudinal folding line (L'₅ L",

L"') suited to define one pair of longitudinal laps (S\ S") that will form the corresponding opposite sides (Ρ', P") of the bags (B), characterized in that said folding station (3) comprises means (6) for guiding the strip (N) suited to match said longitudinal laps (S\ S") by rotating both said longitudinal laps (S\ S") from a substantially plane horizontal position to a substantially vertical position.

2. System according to claim 1, characterized in that said guide means (6) of said folding station (3) comprise at least two constrained cylinders (7) turning around corresponding substantially vertical rotation axes, each one of said vertical cylinders (7) having the side wall (8) destined to interact with said longitudinal laps (S\ S' ') of the strip (N).

3. System according to claim 1 or 2, characterized in that said guide means (6) of said folding station (3) comprise at least one slide pad (9) suited to carry out at least a partial folding of the strip (N) along longitudinal folding lines (L", L"').

4. System according to claims 1 or 2 or 3, characterized in that said guide means (6) of said folding station (3) comprise at least one constrained disc (11) turning around a rotation axis that is substantially horizontal and transversal to the advance direction, and having a peripheral wall (12) that is in contact with the strip (N) and is positioned at the level of the longitudinal folding line (L^f) between the longitudinal laps (S¹, S").

5. System according to one or more of the preceding claims, characterized in that said guide means (6) of said folding station (3) comprise at least one substantially horizontal supporting and tensioning edge or roller (13) positioned upstream and at a different height with respect to said at least one slide pad (9) and said at least one constrained disc (11).

6. System according to one or more of the preceding claims, characterized in that said at least one pad (9) sliding on a horizontal plane is positioned upstream of said at least one constrained disc (11).

7. System according to one or more of the preceding claims, characterized in that said folding station (3) comprises one or more moving guides (14, 14') suited to support and move said at least one slide pad (9), said at least one constrained disc (11) and said pair of vertical cylinders (7).

8. System according to one or more of the preceding claims, characterized in that it comprises, downstream of said folding station (3), at least one station (15) for compressing the longitudinal laps (S\ S") that substantially face each other, said compression station (15) being provided with a plurality of constrained compression rollers (16) turning around substantially vertical axes, and wherein said compression rollers (16) drive said folded strip (N).

9. System according to one or more of the preceding claims, characterized in that it comprises, downstream of said compression station (15), at least one station (17) for cutting the individual bags (B) from the continuous strip (N), said cutting station (17) being provided with one or more moving blades (18) arranged in a substantially vertical direction.

10. System according to one or more of the preceding claims, characterized in that it comprises, upstream of said folding station (3), at least one station (4) for making longitudinal and/or transversal creases, and at least one station (5) where the handles (M) are applied.

11. System according to one or more of the preceding claims, characterized in that it comprises at least one upper glueing device (5') for spreading glue on the upper side of the strip N, positioned upstream of said folding station (3), and at least one lower glueing device (5") for spreading glue on the lower side of the strip N, positioned downstream of said horizontal edge or roller (13) and upstream of said constrained disc (11).

12. System according to one or more of the preceding claims, characterized in that it comprises, downstream of said cutting station (17), at least one overturning device or conveyor (19) that overturns the finished bags (B) from the substantially vertical position to a substantially horizontal position for the successive packaging and storage operations.