Machine for making tubular bags

ES 2 242 176 T3

DESCRIPTION

Machine for forming, filling and sealing bags.

The invention relates to a machine for continuously forming, filling and sealing bags with a continuous sheet, a feeding roll, reversing pulleys for feeding the flat continuous sheet to a forming heel, a sheet unwinder for the conveying the web, jaws of a transverse welding device to produce transverse seams, a cutting device to cut the tube from the foil and with flat separating elements connected to the filling tube that are distanced from the filling tube, where an edge welding device is provided in each case for each separating element arranged downstream of the separation elements in the direction of film transport, edge welding device directed against the edge of the film tube deflected in each case by a separating element.

A known machine of this type for forming, filling and sealing bags is used for the production of bags from a flexible tube, the four edges of which are welded. These flexible tube bags have relatively good stability.

In a machine for forming, filling and sealing bags known from EP 0 627 355 A, a longitudinal cord arranged in the center of the bag is produced by means of a symmetrical shaping heel. The edges of the bag are welded separately so that a bag has five longitudinal weld beads.

Furthermore, from IT 0 127 41 00 B, such a machine for forming, filling and sealing bags is known, in which a longitudinal cord in the form of an overlapping cord comes into contact with a foil tube.

A bag with only four longitudinal seam beads does not have any longitudinal seam that adversely affects the printing on the bag. For the production of a bag with a central longitudinal cord that interrupts the impression on the bag, a traditional symmetrical forming stub is used.

The known machines for forming, filling and sealing bags do not offer the possibility of producing bags with an easy-to-use opening aid or with an aid for repeated closing, so that this aid takes advantage of the special shape of the bag welded to it. along its four edges.

The object of the invention is to eliminate this disadvantage in a machine for forming, filling and sealing bags according to the preamble of the claim.

1.

This object is achieved according to the characterizing part of claim 1. A separate longitudinal welding device is provided to weld the area adjacent to the edge of the sheet tube. By using the asymmetrically shaped heel, the longitudinal cord, which otherwise passes through the center of the bag, is moved to the area of ​​one edge of the bag, so that a separate longitudinal cord is no longer produced that passes through the center. The longitudinal welding device is offset in the direction of the edges of the sheet compared to the welding device of the adjacent edges.

The advantage of the invention is that due to the two welding devices provided at one edge of the foil tube, i.e. an edge welding device and the separate longitudinal welding device, two directly adjacent longitudinal seams are produced at the area of ​​the edge of the sheet tube along which the sheet tube is longitudinally closed. Of these two longitudinal cords, one can be provided as relatively secure against opening and not reclosable, and the other cord can serve as an easy-to-open and reclosable cord. Alternatively, one cord fulfills, due to its edge sealing, in the first place the purpose of stabilizing the bag while the other cord serves as a secure closure for the bag. In this case, for example, the edge welding seam, in general, has a lower resistance than the longitudinal seam that seals the bags.

A bag produced in this way is of particular importance also if the outer drawstring, that is to say the drawstring to be opened first, is a drawstring that opens easily, and the adjacent drawstring fulfill the function of stabilizing the edges. The cord that opens first may have an aid for repeated closing.

Because the longitudinal welding device is offset towards the edge of the sheet in front of the adjacent edge welding device, the longitudinal welding device provides closure of the sheet tube at that point where the two edges of the sheet meet. find. These edges are followed by an edge zone. This arrangement allows in a simple way the production of bags welded on all four edges with a longitudinal cord limited by one edge. The edge can also be formed without the bag closure feature.

The proposed machine for forming, filling and sealing bags is used to obtain bags whose edge of the foil contacts the bag in the form of a cord overlapped in the bag (foil tube). The contact can be provided by means of a corresponding soldered connection.

Due to the fact that a device has been installed in the flat continuous sheet to place a bag opening aid or a repeated closing aid, since this aid is intended for integration into the longitudinal cord and / or the edges to be welded, It is possible to equip a selected lanyard with a corresponding aid. As an aid, according to claim 2, especially a layer in the form of a strip that can be removed, in order to achieve an easy opening after grasping the edges of the sheet, an adhesive tape on both sides, to achieve a closure secure in connection with a possibility of repeated closure, as well as a “Zipp” repeated closure strip to take advantage, in particular, of several repeated closures.

The bag forming, filling and sealing machine can operate in continuous or synchronized mode. The operation of the extraction of the sheet proceeds correspondingly. Circulating sealing strips for longitudinal welding (claim 3) and a rotating system of transverse jaws are suitable for continuous operation. With synchronized operation, hot sealing jaws can be used that are operated synchronously (claim 4).

ES 2 242 176 T3

Devices for producing side folds serve to produce side folds in a sheet tube. A pair of devices are used to produce side folds that move towards each other, to produce two opposite side folds in the sheet tube. In this way, by means of two pairs of lateral folding devices, one pair being provided in the direction of transport of the sheet and one pair after the transverse sealing device (claim 5), bags are welded from a tube of foil, each bag with two opposite transverse cords. These bags are very stable in shape. They are welded at the top and bottom with the help of transverse welds. The lateral folds are integrated by welding into the transverse welds. If the distance of one pair from the transverse welding device is equal to the distance of the other pair from the transverse welding device (claim 6) the bag is symmetrical in its lateral pleat arrangement and may have a relatively round shape, to give it a similar appearance to a boat once lifted on the edges, and serve advantageously as a replacement for cans (material saving).

If the forming stub has a side slot through which the edge of the sheet is drawn (claim 7), the bag forming, filling and sealing machine can be equipped with a traditional but slotted asymmetric forming stub.

The pre-shaping of the edges can be carried out in the simplest technical way and is independent of the operating conditions of the machine for forming, filling and sealing bags, if, according to claim 8, two are provided in the area of ​​the shaping heel. Sheet retaining devices each arranged between two sheet spacers to preform the sheet tube for edge welding. These sheet spacers are mounted on the fill tube to achieve a secure preform (claim 9).

The machine according to the invention for forming, filling and sealing bags is described in more detail below with the help of a figure, which shows:

- Figure 1, a side view of the principle of a machine for forming, filling and sealing bags to produce a bag obtained from a flexible tube with the help of an asymmetric shaping heel to deform a flat continuous sheet and form a sheet tube , with a narrowing filling tube, with flat separating elements, with closed circulating jaws of a transverse welding device, with edge welding devices directed against the deflected edges of the hose as well as with a separate device for longitudinal welding.

In a vertical bag forming, filling and sealing machine 1, a flat web 2 is unwound from a feed spool 3 and driven to an asymmetric forming heel 5 above a deflection pulley 4 (Figure 1). The collar-front portions 34, 35 of the shaping bead 5 have different lengths. A film extractor 6 serves for the subsequent transport of the continuous film 2. A filling tube 7 receives the continuous film 2 which forms a film tube. The jaws 9, which move towards each other, of a transverse welding device 10, serve to make transverse seams 11 in the foil tube 8. In one of the jaws 9 a cutting device 12 is provided for cutting the foil tube 8 between, in each case, two transverse cords 11. The bag obtained is filled through the filling tube

13.

Four flat separating elements 14 are connected to the filling tube 7, which are spaced from the filling tube 7. In the direction of film transport after the separating elements

14, that is to say below the separating elements 14, an edge welding device 15 is provided for each separating element 14, edge welding device 15 which is directed in each case against an edge of the flexible tube diverted by a separating element 14.

The forming butt 5, moves the edges of the sheet 17, placed one above the other, to the right towards the side of the sheet tube 8. A separate device for longitudinal welding 18 is provided to weld the area adjacent to the edge of the flexible tube, to produce two directly adjacent weld beads. The longitudinal welding device 18 produces a longitudinal bead 20, while each edge welding device 15 produces a welded edge 21 on the sheet tube 8. The longitudinal welding device 18 is offset towards the edge of the sheet 17 in front of the edge welding device 15 adjacent. The edge of the sheet 17 is made in the form of an overlapped weld.

The extraction of the sheet 6 is carried out continuously. The longitudinal welding device 18 and the edge welding devices 15 are continuously actuated circulating sealing strips. The edge welding devices 15 have, in each case, a counter-bearing.

Two pairs 24, 25 of lateral folding devices 26 are provided in the transverse welding device 10. The two lateral folding devices of a pair 24, 25 move towards each other and in the sheet tube 8 which is located between the two, in order to produce lateral folds in the bag 13. A pair 24 is provided in the direction of transport of the sheet in front and a pair 25 behind the transverse sealing device 10. The distance of one pair 24 from the transverse welding device is, seen in the transport direction of the sheet, equal to the distance 27 of the other pair 25 from the transverse welding device 10.

The forming bead 5 has a lateral groove through which the edge of the sheet 17 is pulled out. In the area of ​​the forming bead 5, two sheet retaining devices 29 are provided in the filling tube 7, arranged each between two foil spacers 30 to previously shape the foil tube 8 for an edge welding 21.

A device 31 is mounted on the flat web 2 to place a bag opening aid 32. The bag opening aid 32 consists of a removable strip-shaped layer that is integrated into the longitudinal cord 20 and serves to more easily open a bag 13 produced in this way.

The bag 13 has four lateral folds 33 and is closed in its upper and lower part in each case by means of a transverse cord 11. Next to one of its four welded edges 21 there is a long cord.

ES 2 242 176 T3 tudinal 20. The removable strip-shaped layer within the longitudinal cord allows easy opening of the longitudinal cord 20 by pulling it. The produced bags 13 can be lifted on their edges 21 in which there is no longitudinal cord 20. It is then possible to open the longitudinal cord 20 located at the top to extract the product from bag 13. The edges 21 stabilize bag 13. Also the edges 21 adjacent to the longitudinal cord 20 can be hermetically closed and in the longitudinal cord 20 an adhesive tape can be found on both sides or a "Zipp" repeat closure strip, to achieve a simple repeated closure of the bag 13. As alternatively, the longitudinal cord 20 can also be hermetically welded and the adjacent edge 21 can have a repeated closing aid. For this purpose it would be necessary in this case to move the device 31 a little towards the center 36 of the web.

Bag forming, filling and sealing machine

Continuous foil

Power coil

Reversing pulley

Forming heel

Foil extraction

Filling tube

Foil tube

Jaw

Cross welding device

Cross chord

Cutting device

Bag

Separation element

Edge welding device

Foil tube edge

Sheet edge without welding

Longitudinal welding device

Longitudinal chord

Soldier song

24, 25 Pair

Side folding device

Distance

Groove

Sheet retention device

Sheet separator

Device for placement

Bag opening aid

Side fold

34.35 Collar-front part

Center of web 2