WO2008120062A2

WO2008120062A2 - Process and apparatus for making bags and plastic film bag

Info

Publication number: WO2008120062A2
Application number: PCT/IB2008/000703
Authority: WO
Inventors: Nora Perdoni
Original assignee: BORDI CARLO Srl
Current assignee: BORDI CARLO Srl
Priority date: 2007-03-30
Filing date: 2008-03-26
Publication date: 2008-10-09
Anticipated expiration: 2009-09-30
Also published as: WO2008120062A3; ITBO20070230A1

Abstract

In a process and in an apparatus for making bags (50), a film (51), preferably a flexible plastic film, is fed from a suitable roll (53) and at least one indented pleated portion is made in the film (51), in particular a first and a second indented pleated portions (56, 58) having a first and a second flap (56a, 56b and 58a, 58b), wherein the corresponding indented pleated portion (56, 58) has at least one respective longitudinal end (56', 56' and 58', 58'). Advantageously, a corresponding part (56'a, 56'a, 58'a, 58'a) of the pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (52) opposite, immediately after, or downstream of, the step of forming the pleats (56, 58) and, in any case, before making the film (12) into a tube. The invention also relates to a bag made of flexible plastic film.

Description

PROCESS AND APPARATUS FOR MAKING BAGS AND PLASTIC FILM BAG.

Technical Field

The present invention relates mainly but not exclusively to a process for making bags.

The bags are preferably obtained starting with a plastic film, in particular a flexible plastic film, especially a plastic film consisting of a plurality of layers.

The bag is preferably but not exclusively intended for packaging foodstuffs, including pet foods.

Background Art In this field, bags made of flexible plastic layered material to contain products, in particular foodstuffs, are known. These bags comprise a front face, a rear face and side faces, in the form of respective V-shaped pleats.

Some prior art bags have an upper tubular mouth without pleated parts which can be opened and closed by means, consisting of a zip, extending across the full width of the bag to also form means for sealing the upper end of the bag side pleats.

The bag normally has images and writing printed all around it, on its front, rear and side faces.

In a first prior art process for making a bag of this kind, a film designed to form a front or rear face of the bag is fed lengthways and a continuous strip of material to form the bag closing zip is fixed at a suitable distance from one of the longitudinal edges of the film and in a direction parallel with the longitudinal edge.

A large sheet is cut from the film fed lengthways to form one of the bag's main walls and is joined to an opposite large sheet to form the bag's other main wall. At the same time, smaller lengths of film to form the pleated side walls of the bag are fed in transversally and placed between the upper and lower large sheets.

This process for making the bag, however, requires a large number of rolls of film on which respective printing operations are performed. In practice, an extremely large number of operations are required to print images and writing on the faces of the film webs that will form the front, rear and pleated side walls of the bag. As a result, bags of this kind are expensive to produce and not always good quality. Indeed, the process of assembling two or more films is a tricky one and often leads to badly made, poor quality bags, and requires complex machines 5 which are difficult to make.

In another prior art method, a single web of printed film is fed, this sheet has transversally aligned openings made in it along the longitudinal zones or portions of the film to form the side pleats of the bag; The sheet of film is then folded into a tubular shape by joining its longitudinal end edges after a zip or other0 suitable means for opening and closing the bag has been positioned transversally. Once the film has been folded and sealed into a tubular shape, suitable V-shaped side portions to form the pleated side faces of the bag are provided and a series of transversal seals are made in the tube, each forming the bottom of a bag when the tube is cut into separate bags as it advances. 5 One disadvantage of bags obtained using the prior art procedure just described is the risk that bag quality will not be optimum. This is because the transversally aligned openings weaken the structure of the film, creating edges and surfaces that tend to move out of line and form creases as the film advances resulting in misalignment between the portions of film intended to form the o different parts of the bag.

Disclosure of the Invention

A process for making bags is provided, in which a film is fed, preferably a plastic film, in particular a flexible plastic film, making at least one indented5 pleated portion and, in particular, a first and a second indented pleated portions; characterised in that a corresponding part of the respective pleated portion is joined to a corresponding part of the film face opposite.

In this way, the pre-folded film is made more stable during feed, being advantageous in terms of the precision with which the subsequent operations are o performed.

In particular, a corresponding part of the respective pleated portion is joined to a corresponding part of the film face opposite before the film is made into a tube.

Other advantageous aspects of this process are described in the claims 5 herein.

The invention also relates to an apparatus and a bag as described in the claims herein. The invention also relates to a film for making bags and a web of bags as described in the corresponding claims.

Brief Description of the Drawings These and other technical characteristics of the present process, apparatus and bag are clearly described in the claims below and the advantages are more apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate preferred, non-limiting embodiments of the invention provided merely by way of example, and in which: - Figure 1 is a perspective schematic view of an embodiment of a bag which can be obtained using the present preferred process;

Figures 2A and 2B are perspective schematic views of the various steps for making a bag, in particular a bag like that of Figure 1, in accordance with a first preferred embodiment of the process and apparatus according to the present invention;

Figure 3 is a schematic top plan view of the zone where the reinforcing seal is made between the pleat and the end of the film below, in accordance with the first preferred embodiment of the process and apparatus;

Figure 4 is a schematic cross-section of the zone where the reinforcing seal is made between the pleat and the end of the film below, in the condition prior to making the seal, in accordance with the first preferred embodiment of the process and apparatus;

Figure 5 is a schematic cross-section of the zone where the reinforcing seal is made between the pleat and the end of the film below, in the condition of making the seal, in accordance with the first preferred embodiment of the process and apparatus;

Figure 6 is a perspective schematic view of the zone where the reinforcing seal is made between the pleat and the end of the film below, in the condition prior to making the seal, in accordance with the first preferred embodiment of the process and apparatus;

Figure 7 is a perspective schematic view of the zone where the reinforcing seal is made between the pleat and the end of the film below, with the film in the condition in which it is closed in a tubular shape, in accordance with the first preferred embodiment of the process and apparatus;

Figure 8 is a schematic cross-section of the zone where the bag closing zip is positioned and sealed, in accordance with the first preferred embodiment of the process and apparatus; - Figure 9A is a perspective schematic view of a second and advantageous embodiment of the bag;

Figure 9B is a schematic cross-section of the upper zone of the second embodiment of the bag, in the filled condition;

Figure 1OA is a perspective schematic view of the zone where the bag closing zip is provided and sealed, in accordance with a second preferred embodiment of the process and apparatus according to the present invention;

Figure 1OB is a perspective schematic view of the zone where the bag closing zip is provided and sealed, in accordance with the second preferred embodiment of the process and apparatus according to the present invention, seen from a different angle to that of Figure 1OA;

Figures 1 IA to 1 ID are top plan views of the various steps of providing and sealing the bag closing zip, in accordance with the second preferred embodiment of the process and apparatus according to the present invention;

Figure 12 is a perspective schematic view of the zone where the means for sealing the bag pleat are provided and sealed, in accordance with the second preferred embodiment of the process and apparatus according to the present invention;

Figure 13 is a perspective schematic view of the zone where the bag closing zip is provided and sealed, in accordance with a third preferred embodiment of the process and apparatus according to the present invention;

Figure 14 is a perspective schematic view of the zone where the bag closing zip is provided and sealed, in accordance with a fourth preferred embodiment of the process and apparatus according to the present invention;

Figure 15 is a perspective schematic view of the zone where the means for sealing the bag pleat are provided and sealed, in accordance with a fifth preferred embodiment of the process and apparatus according to the present invention;

Figure 16 is a perspective schematic view of the zone where the means for sealing the bag pleat are provided and sealed, in accordance with a sixth preferred embodiment of the process and apparatus according to the present invention;

Figure 17 is a perspective schematic view of the zone where the means for sealing the bag pleat are provided and sealed, in accordance with a seventh preferred embodiment of the process and apparatus according to the present invention;

Figures 18A to 18D are top plan views of the various steps of providing and sealing the band for closing one end of a bag pleat, in accordance with an eighth preferred embodiment of the process and apparatus according to the present invention;

Figure 19 is a perspective schematic view of the zone where the means for sealing the bag pleat are provided and sealed, in accordance with the eighth preferred embodiment of the process and apparatus according to the present invention; - Figure 20 is a perspective schematic view of the grippers for feeding and positioning the means for sealing the bag pleat, in accordance with the eighth preferred embodiment of the process and apparatus according to the present invention.

Detailed Description of the Preferred Embodiments of the Invention

Figure 1 illustrates a preferred embodiment 10 of a bag made of plastic film, obtained according to a first preferred embodiment of the process in accordance with the present invention.

As shown in the drawings, the bag 10 comprises a front wall 12, a rear wall 14 and opposite side walls 16, 18, made in such a way as to form generally V- shaped indented pleats.

As illustrated, the pleats or side walls 16 and 18 consist of respective longitudinal portions 19, 21, and 23, 25 extending from the respective edges 12a, 14a and 12b, 14b of the front and rear walls 12 and 14. The numerals 16a and 18a denote the longitudinal connecting and folding edges between the indented pleated portions or panels 19, 21 and 23, 25.

The bottom of the bag 10 is made by joining or sealing opposite lower transversal ends of the front and rear walls 12, 14.

As shown in Figure 1, when the bag is full, the lower portions or zones of the front and rear walls 12, 14 contribute to forming the bottom of the bag.

At the top, the bag has a product access opening 30 defined by a tubular collar or mouth 32 without pleated side zones.

In practice, the mouth 30 is formed by opposite upper ends of the front and rear walls 12, 14, which are joined together, or sealed, at the opposite lateral ends 12d, 14d and 12e, 14e.

Means 34 are provided for opening and closing the mouth 30 and consisting, in particular, of a zip comprising a first fastening element 34a, on the wall 12, and a second fastening element 34b, on the rear wall 14, that can be reciprocally engaged and disengaged.

Said fastening elements 34a and 34b are supported by respective supporting elements or strips 36a, 36b, which are joined, in particular sealed, to respective inner faces 12' and 14' of the walls 12 and 14.

Although not illustrated in detail, said elements which can be reciprocally engaged and disengaged 34a, 34b are, in the known way, of the type comprising at least one respective portion, or projection, which is inserted in a cavity formed between opposite portions or projections on the other element.

The fastening elements 34a and 34b may, however, be of any suitable type within the knowledge of an expert in the trade and made in such a way as to be easily disengaged and engaged, in particular disengaged by pulling the upper portions of the front and rear walls 12 and 14 apart to open the bag, and engaged by pressing the portions 12d, 14d together again to close it.

In particular, as illustrated, the bag closing means 34 comprise supporting elements or strips 36a, 36b and fastening elements 34a, 34b which are made in a single body with the respective supporting element 36a, 36b .

The supporting elements 36a, 36b comprise a respective first flange or band 36"a, 36"b, extending from the respective fastening element 34a, 34b towards the outside of the bag, and a respective second flange or band 36'a, 36'b, extending from the respective fastening element 34a, 34b towards the inside of the bag. In practice, both the first and second flanges 36'a, 36'b and 36"a, 36"b of each supporting element or strip 36a, 36b are sealed to the respective wall 12, 14 of the bag 10.

As illustrated, there are longitudinal seals or joins, labelled 31, 33, 35, 37, at the edges 12a, 14a and 12a and 14b for respectively connecting the front wall 12 and the rear wall 14 with the portions 19, 21, 23, 25 forming the bag side pleats.

The bag 10 also comprises pleated side walls 16, 18, having a respective upper end 16' (illustrated with a dashed line in Figure 1), which is closed or sealed by a band or strip 40 placed over it.

The band 40 is suitably attached or sealed on top of the upper ends 16', 18' of the pleats 16, 18, which are arranged in contact with a corresponding wall, in particular, as illustrated, the inner face 14' of the bag rear wall 14. The band 40 is also fixed or sealed to the corresponding face 14' of the bag wall 14. In this way, the inside of the bag remains perfectly sealed from the outside environment.

The band 40 consists of a strip of material whose front face 40a is towards the inside of the bag and which has an opposite face 40b engaging with and joined to the inner face 14' of the bag rear wall 14 and the inner face 19', 23' of the corresponding pleat 16, 18 panels 19, 23, projecting above it.

As illustrated, the upper mouth 30 closing means consist of a zip 34 which is attached in a position longitudinally distanced from the band 40, in the direction of the upper edge of the bag 10.

However, according to other embodiments, not illustrated, the zip may also be positioned directly above the band 40, at the same height as the band, or even in a position longitudinally below it.

In practice, the zip would not be used to close the upper end of the pleats but would constitute simple opening/closing means allowing access to or the outflow of the contents of the bag on a number of occasions. According to another embodiment, the band 40 could be substituted with a portion, or flange, 36b of the zip for closing the upper end of the pleats 16 and 18.

As illustrated in Figures 2A and 2B, according to a preferred process, which can preferably be implemented by a single apparatus or production line to make a bag according to the embodiment shown in Figure 1, there is a step of unwinding a film of plastic or plasticised material 51 from a roll 53, where said film has a sealable face, in particular heat-sealable, 51', and an opposite face 51" which is not sealable and which is printed with appropriate writing, colours and images on predetermined areas of it, corresponding to predetermined parts of the front, rear and side faces of the finished bag. According to the present preferred, advantageous embodiment, the film of plastic material 51 is fed with continuous motion in predetermined zones, and with intermittent motion having film feed and film dwell steps in other zones, as described in more detail below.

The layered plastic film 51, in a flat condition, has its opposite longitudinal edges 5 Ia, 5 Ib extending parallel with the longitudinal direction of film feed.

This process comprises, in a first operating station, corresponding to a zone in which the film is fed with intermittent motion, a step of making in the film 51 the openings 55, 57 transversally aligned with and distanced from each other on the extension of the corresponding longitudinal zones or strips 56, 58 of the film 51 itself that will form a respective pleated side 16, 18 of the bag and which are illustrated with dashed lines in Figure 2A.

5 As shown in Figure 2A, the openings 55, 57 have a quadrangular shape obtained using suitable cutting elements or punches 55', 57', forming means for making the openings, schematically illustrated, which move up and down and which cut the openings 55, 57 during the step in which the film or web 51 is not being fed forward. Obviously, the openings 55 and 57 could also be punched during film feed0 by using suitable means which track the film as it is fed forward. Obviously, making said openings 53, 57 which produce the upper part of the bag without pleats, means removing material.

In a subsequent station or step of this process, V-shaped pleated portions are formed in the flat film 51, using blades or means for forming the pleats in the film,5 schematically illustrated in Figure 2A and labelled 61 and 63.

In this condition, the flat film 51, according to the present preferred embodiment, is divided into V-shaped portions, 56 and 58, suitable for forming the respective pleated side wall 16, 18 of the finished bag, and into flat portions 52, 54, designed to form the front and rear walls 12 and 14 of the bag. o This pleating step is carried out while the film is fed with continuous motion, allowing optimum execution of the pleat folds.

For this purpose, the present part of the apparatus is separated from the upstream part, for making the openings 55 and 57, by compensation means which specifically consist of a roller 59 able to move vertically, which allows the film to be5 kept taut between two successive zones in which the film moves with a different type of motion. There are similar compensation means 59' upstream of the zone between the punches 55', 57' and the roll 53.

As illustrated, in this condition, the pleated side portion 56 is delimited by a folding edge 54a (shown with a dashed line) which joins the part 54 of the film that o will form the rear wall 14 of the bag to the corresponding portion 56a that will form the pleated side 16 of the bag. Also, in this condition, the other section, or flap, 56b of the portion that will form the pleated side 16 extends in the same plane as the part 52 of the film that will form the front wall 12 of the bag. Said flaps 56a and 56b of the pleated portion 56 are divided, or connected to each other by an inner folding 5 edge labelled 516a.

As illustrated, in this condition, the pleated side portion 58 is in turn defined by a connecting edge 54b which joins the part 54 of the film that will form the rear wall 14 of the bag to the corresponding portion 58a that will form the pleated side 18 of the bag. Also, in this condition, the other section, or flap, 58b of the portion that will form the pleated side 18 extends freely outwards and ends with an edge 52b, coinciding with the edge 51b of the film 51 and which will be attached to the lateral edge 51a of the wall 52 that will form the front wall 12 of the bag. Said flaps 58a and 58b of the pleat 58 are divided by an inner folding edge labelled 518a.

In practice, according to this process pleated side portions 56, 58 are made in the film 51 before closing the film into a tubular shape, as indicated in more detail in the following description, in particular before connecting or joining the lateral edges 51a, 51b of the film 51.

As illustrated, the first and second indented pleated portions 56, 58 have respective longitudinal ends 56', 58' to be hermetically closed or sealed, as described in more detail below, to isolate the inside of the bag from the outside environment. The first and second indented pleated portions 56, 58 also have additional opposite longitudinal ends 56", 58", closed or sealed at the moment of making the transversal seal at the bottom of the bag with sealing means, described in more detail below.

In a subsequent station or step of this apparatus or process which, as illustrated, is preferably immediately downstream of the zone where the pleats are made, joining means are used to join a part 56'a, 56"a, 58'a, 58"a of the respective portion, or flap, 56a, 58a of the pleat to a part 546a, 546b, 548a, 548b of the film face 54 opposite, as may be inferred in particular from Figure 3 and Figures 6 and 7.

Said joining of part of the respective pleated portion 56a, 58a to a part of the film face 51' opposite is performed immediately downstream of the pleat forming zone.

This preliminary joining of one pleat flap to the opposite film flap, performed while folding the film and making the bag, labelled 56's, 56"s, 58's, 58"s, allows the film to be made more stable during the subsequent steps. This advantageously allows precision execution of subsequent operations and the production of a precision, well-finished bag using this process.

As illustrated, advantageously, said part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is joined to a corresponding part 546a, 546b, 548a, 548b of the film face 51' opposite before the film 12 is closed a tubular shape. As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the means for closing the film in a tubular shape, according to the direction of film feed. In this way, the pre-folded film is made more stable during the step of closing the film in a tubular shape, being advantageous in terms of the precision with which the latter operation is performed.

As illustrated, advantageously, said part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is also joined to a corresponding part 546a, 546b,

548a, 548b of the film face 51' opposite before attaching the pleat sealing means 40 to the film. As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the means for attaching the pleat sealing means, according to the direction of film feed. The means for attaching the pleat sealing means are, in particular, means for applying a band to the film 51.

In this way, the pre-folded film can be made more stable during the application of the pleat sealing means, being advantageous in terms of the precision with which the latter operation is performed.

According to another aspect, advantageously, the part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is joined to a corresponding part 546a,

546b, 548a, 548b of the film face 51' opposite before attaching the bag opening/closing means, or zip, 34 to the film. As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the means for attaching or applying the bag product outflow mouth opening/closing means, according to the direction of film feed.

In this way, the pre-folded film can be made more stable during the application of the bag opening/closing means, being advantageous in terms of the precision with which the latter operation is performed.

As illustrated, advantageously, at 56's, 56"s, 58's, 58"s, the part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is joined to a corresponding part 546a, 546b, 548a, 548b of the film face 51' opposite, before making the transversal seal 44 which will form the bottom of the bag. As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the transversal sealing means, according to the direction of film feed. In this way, the pre-folded film can be made more stable during the bottom

44 joining step, being advantageous in terms of the precision with which the latter operation is performed.

Advantageously, said part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is also joined to a corresponding part 546a, 546b, 548a, 548b of the film face 51' opposite before making the longitudinal seals at the sides of the pleats.

As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the means for making the longitudinal seals at the sides of the pleats, according to the direction of film feed.

In this way, the pre-folded film can be made more stable during the pleat edges longitudinal joining step, being advantageous in terms of the precision with which the latter operation is performed.

5 As illustrated, advantageously, said part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a is also joined to a corresponding part 546a, 546b, 548a, 548b of the film face 51' opposite before pleat longitudinal trimming. As illustrated, the means for joining the respective pleated portions to the film face opposite are upstream of the means for longitudinal trimming of the sides of the bag, l o according to the direction of film feed.

In this way, the pre-folded film can be made more stable during the step of trimming a longitudinal portion of the longitudinal edge of the pleats, being advantageous in terms of the precision with which the latter operation is performed.

As illustrated, advantageously opposite longitudinal ends 56'a, 56"a, 58'a, 15 58"a of the respective pleated portion 56a, 58a are joined to the film face 51' opposite, the pleated portion delimited by successive openings 55, 55 and 57, 57 in the film 52.

This increases pre-folded film feed stability.

However, it shall be understood that it would be possible to seal or join just 20 one end 56'a, 58'a or 56"a, o 58"a of the respective pleated portion 56a, 58a to a corresponding part 546a, 548a or 546b 548b of the film face 52 opposite, to still obtain satisfactory pre-folded film feed stability.

As illustrated, advantageously, said join between a part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a and a corresponding part 546a, 546b, 25 548a, 548b of the film face 51' opposite, extends transversally, in particular across the full width of the respective flap of the pleat.

This provides a high level of pre-folded film feed stability.

In particular, the joined parts of the pleat flap and of the opposite face 51' of the wall 54 of film have a shape which extends transversally, in particular a 3 o rectangle with the long side extending transversally to the film or to the longitudinal direction of film feed.

However, it would also be possible to partly join, in the transversal direction, the respective pleat flap 56a, 58a to a corresponding portion of the opposite face 51' of the wall 54 of film.

35 For example, it would be possible to join only a corresponding part of the respective pleated portion 56a, 58a located close to or extending from the inner edge 516a, 518a of the pleat to a corresponding part of the opposite face 54 of the film. Or it would also be possible to join in particular only a corresponding part of the respective pleated portion 56a, 58a located close to or projecting from the outer edge 54a, 54b of the pleat to a corresponding part of the opposite face 52 of the film.

It would also be possible to join in particular only a corresponding intermediate part of the respective pleated portion 56a, 58a located between the inner edge 516a, 518a and the outer edge 54a, 54b of the pleat, to a corresponding part of the opposite face 54 of the film.

According to another aspect, at said join between a corresponding part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a and a corresponding part 546a, 546b, 548a, 548b of the opposite face 54 of the film, subsequently, or in a downstream station, the transversal seal 44 forming the bottom of the respective bags is made. In this way, this intermediate reinforcing join does not leave substantial traces in the finished bag, in particular at the lower end of the respective pleat. Advantageously, said join between a part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a and a corresponding part 546a, 546b, 548a, 548b of the opposite face 51' of the film is made while the film 51 is fed forward.

In this way, providing this intermediate reinforcing join does not slow the normal bag making process. Advantageously, the means for joining a part 56'a, 56"a, 58'a, 58"a of the respective pleated portion 56a, 58a to a corresponding part 546a, 546b, 548a, 548b of the opposite face 51' of the film are sealing means.

The preliminary retaining join 56's, 56"s, 58's, 58"s is made while the film 51 is fed forward, in particular while the film 51 is fed forward with continuous motion, in the zone of the apparatus which also forms the pleats, immediately downstream of these.

For this purpose there are sealing plates 65, 67 which track the film feed motion while in contact with it over a predetermined distance then are lifted and go back to the lowered starting position to begin a new retaining join, as indicated by the arrows "S", "E", "R" in Figure 2A and as shown in Figures 4 and 5.

However, it shall be understood that, although it is particularly preferable that the joining seals 56's, 56"s, 58's, 58"s should be made while the film is fed forward, the seals could also be made during a film feed dwell period.

As is indicated more clearly later in this description, longitudinal joining strips or seals will be made in the film tube, respectively labelled 43, 45, 47, 49 in the accompanying drawings.

The longitudinal end strips 43 and 45 are made between the portion of film 54 that will form the rear face 14 of the bag and the corresponding pleated portion 56a, 58a, and the longitudinal end strips 47, 49 will be made at the zones joining the pleated portions 56b, 58b and the portion 52 that will form the front face 12 of the bag.

5 For this purpose, it would also be possible to make, in this step or zone of the apparatus, in particular immediately downstream of the means which make the above-mentioned transversal join between the respective flap of the pleat and the face 54 of the film, a longitudinal seal at the edges between the portion of film 54 that will form the rear face 14 of the bag and the corresponding pleated portion 56a,0 58a, so as to form the longitudinal end strips 43 and 45 in an upstream zone of the present apparatus and thus obtain increased film tube rigidity during feed, allowing more precise execution of the subsequent operations.

In this way, as is clearer below, the longitudinal edges 43, 45 of the respective pleats are joined in an upstream station or before the film 12 is closed in a5 tubular shape, or in an upstream station or before the pleat sealing means 40 are attached to the film, or in and upstream station or before the bag opening/closing means 34 are attached to the film.

Moreover, in this way the longitudinal edges 43, 45 of the respective pleats are joined in an upstream station or before the transversal seal 44 is made, which o will form the bottom of the bag, or in an upstream station or before the join 47, 49 is made between the other longitudinal edges of the pleats.

In practice, in this way, the means for joining the longitudinal edges 43, 45 of the respective pleats are upstream of the means for closing the film 12 in a tubular shape, upstream of the means for attaching the pleat sealing means 40 to the film, 5 upstream of the means for attaching the bag opening/closing means 34 to the film, and upstream of the means for making the transversal seal 44 that will form the bottom of the bag.

These longitudinal seals or joins could be obtained with the film 51 being fed forward, using suitable join making means, in particular heated plates (not o illustrated in the accompanying drawings) on which the film conveniently slides. In particular, the seals of the pleat side strips 43, 45 would be made while the film was fed forward with continuous motion.

The subsequent station or step of this process could also operate with the film being fed forward with intermittent motion and is separate from the zone for 5 intermediate and partial sealing of the film, partly folded using compensation means, in particular consisting of a roller which can move vertically and is labelled 69.

There are means for providing pleat sealing means on the film, in particular consisting of means for attaching sealing means 40 to the film.

In the next station, means for sealing the ends of the pleats are applied or provided on the film, the sealing means preferably consisting of a band or strip 40, preferably of heat-sealable material, especially a material that is heat-sealable on both of its sides or faces. Suitable means for attaching the sealing means are used for this purpose.

Figure 2A schematically illustrates the means for positioning the transversal band 40. However, it shall be understood that these means may operate in any suitable way whether transversally or perpendicularly to the film, suitably moving the band, which is cut to the desired length from a web 71 unwound from a roll 73. Obviously, it would also be possible to use a feeder for bands 40 already pre-cut to the correct length.

As illustrated, the band 40 is positioned in particular in the space between the punched openings or holes 55, 57, with the pleated portions in the folded condition, on a part 54 of the film 51 that will form the rear wall 14 of the bag and positioned over the end portions 56'b and 58'b of the upper pleated portions 56b,

58b.

To attach the transversal band 40 to the film 51, suitable joining or sealing means 75, 77, positioned opposite each other, are used. They move vertically towards and against the film, and vice versa, in such manner as to seal the band 40 to the opposite upper face 51" of the film and to the portions 56'b, 58'b of the sections 56b, 58b of the V-shaped folded portions that will form the pleated portions 16 and 18, which are connected to the front wall 12 of the bag. In this way, the respective end 56', 58' of the pleated portions, forming the upper end of the pleats in the finished bag, are sealed.

The sealing band 40 has a main extension length "1", a height or width "h" and minimum thickness, as well as a first and second opposite longitudinal faces, of which only one, labelled 40a, is illustrated in Figure 2A. The band 40 is sealed to the upper face 51' of the film and on top of the ends 56'b and 58'b of the pleats, so that part of the band remains on top of the pleats and part of the band is connected to the face 51' of the film at the margins of the pleats, thus sealing the ends of the pleats.

The strip or band 40 may be made in any suitable way. For example it may consist of a single layer of polythene or similar material that can be sealed to the film the bag is made of, or it may consist of a layered material consisting of two layers, one layer of polythene and another layer for example of polyester or other similar materials that can be sealed to the film the bag is made of, or in any other suitable way. Since the band 40 can be sealed both by its lower face, which comes into contact with the film face 54, and by its upper face 40a, it is possible, as explained below, to seal its upper face 40a to the corresponding part 52 of the film at the lateral ends 40b, 40c of the band 40, thereby imparting added strength to the assembly at these lateral zones.

Figure 2A also schematically illustrates the means for positioning the transversal zip 34 for bag opening/reclosing. For this purpose suitable means for attaching or applying opening/closing means 34 are used. However, it shall be understood that said means may operate in any suitable way, whether transversally or perpendicularly to the film, suitably moving the zip 34, which is cut to the desired length from a tape 79 unwound from a roll 81. Obviously, it would also be possible to use a feeder for zips 34 already pre-cut to the correct length.

The zip 34 is fed to the film in the closed condition, that is to say, in a condition in which its fastening elements 36a and 36b are engaged and the respective supporting flanges, or strips, 34a, 34b, lie opposite one another.

Figure 8 illustrates advantageous means for applying the zip to the film, which advantageously comprise means 84 for positioning the zip, and joining means 83, 85, in particular means for sealing a zip 34 end, or flange, 36'a to the film, that is to say, to the upper heat-sealable face 52 of the film 51 at 83s. The sealing means 83, 85 are downstream of the zip 34 positioning means

84 relative to the direction of film feed indicated by the arrow A in Figure 8.

These sealing means comprise a first and a second heated sealing bar 83, 85, which can move towards each other to clamp the zip 34 against the film and seal the zip to the film at 85s, and can move away from each other to allow the film 51 feed movement.

In this way, as illustrated, the zip flange 36'a seal is obtained which, relative to the position of the fastening elements 34a, 34b, in the finished bag faces the inside of the bag, that is to say, towards the bottom of the bag.

In practice, the means 84 for positioning the zip 34 on the film comprise means for feeding the zip transversally to the film, that is to say, transversally to the longitudinal edges of the film.

In particular, the means 84 for positioning the zip comprise zip supporting means 84, located above the film 51 and extending transversally to the film. They have a recessed housing and sliding cavity for the zip fastening elements 34a and 34b. The cavity forms zip 34 guide and sliding means, the zip being moved along the guide means by suitable feed means.

The feed means, not illustrated in detail in Figure 8, may be, for example, a plurality of feed rollers, suitably distributed along the supporting means, or fixed guide, 84, and can move from the lowered position, that is to say, from the zip engagement and feed position, towards the raised position for disengaging the zip 34 and allowing it to be pulled downstream by the film 51 as the latter is fed forward. As illustrated, the guide 84a is positioned above the portion of film where the zip 34 must be positioned, extending to the film from a lateral zone.

There are also means for cutting the zip 34 from a zip tape 79, not illustrated in detail in the accompanying drawings.

The other flanges of the zip 34 are attached to the film 51 at a station downstream of this station for applying the zip 34 to the film 51.

As illustrated, the zip 34 is positioned in particular outside the space between the punched openings or holes 55, 57, on a part 52 of the film that will form the front wall 12 of the bag. This positioning of the zip 30 and the band 40 on different transversal zones of the film facilitates their mechanical implementation. However, it shall be understood that it would be possible to attach the zip to the film in a position between the openings 55, 57.

Moreover, as illustrated, the zip 34 is placed longitudinally in a position offset relative to the sealing band 40.

However, it shall be understood that the closing zip could be applied in such a way that it is longitudinally distanced from the band 40, alternatively, both in the direction of the upper part of the bag, as illustrated, or towards the lower part of the bag, or in a position such that when the film is closed in a tubular shape it is above, that is to say, over, the band 40.

To attach the transversal zip 34 to the film 51, there are suitable opposite joining or sealing means 83, 85, able to move vertically towards and against the film, and vice versa, in such manner as to seal the flange, or strip, 36a supporting the zip 34 fastening element 34a to the opposite upper face 51' of the film.

In the next step or station for forming the film into a tubular shape, the edges 51a and 51b of the film are drawn near each other by a rotational movement that positions one transversal portion 52 of the film over the other part of the film. Said movement is imparted by means 87 for making the film into a tube.

This forms a tube of film with V-shaped pleated side portions, as shown in Figure 7.

In a subsequent step, or station, illustrated in Figure 2B, the remaining flange 34b of the zip 34 fastening element 36a is sealed to the respective wall 54, which will form the rear wall 14 of the bag, using sealing means 89, 91 positioned opposite each other and able to move vertically towards and against the film, and vice versa. In a subsequent step, or station, illustrated in Figure 2B, transversal joining or sealing means or elements, labelled 93 and 95, are used that move towards each other against the film tube in such a way as to make the transversal seals 44 to form the bottom 12c, 14c of the bag.

5 The numerals 97, 99, 101, 103 in Figure 2B denote longitudinal sealing elements or means, arranged opposite each other in pairs, which move vertically towards each other and towards and against the respective longitudinal portions of the film 51 tube, in such a way as to clamp the longitudinal end strips of the bag to make joining or sealing strips, labelled 43, 45, 47, 49 in the drawings. The0 longitudinal end strips 43 and 45 are made between the film portion 54 that will form the rear face 14 of the bag, and the corresponding pleated portion 56a, 58a. The longitudinal end strips 47, 49 are made at the joining zones between the pleated portions 56b, 58b and the portion 52 that will form the front wall 12 of the bag.

These longitudinal joining means 97, 99, 101, 103 also constitute means for5 joining the lateral end of the pleat sealing band to the inner face of the film wall 52. Thanks to the fact that the band is heat-sealable, in addition to the lower face which engages with the corresponding end of the pleat, the upper face also makes contact with the upper wall 52 that will form the front wall 12 of the bag, due to engagement of the sealing plates 97, 99, 101, 103 with the corresponding lateral ends of the o band, sealing or joining the lateral ends of the band to the inner face of the film wall 52. This gives bags with an improved, secure hermetic seal.

In the next or downstream station or step, illustrated in Figure 2B, there are suitable opposite means or elements 105, 107, 109, 111 for cutting or trimming the film longitudinally, which move vertically towards and against the film, and vice5 versa, and remove the longitudinal ends of the sealed strips 43', 45', 47', 49' at the edges of the bag. The lateral longitudinal ends are labelled 43', 45', 47', 49' in Figure 2B. The width of the lateral joining strips 43, 45, 47, 49 may be between 5 and 15 mm, whilst the longitudinal ends trimmed 43', 45', 47', 49' may be between 0.5 and 6 mm wide. 0 In the next station, illustrated for convenience in Figure 2B, transversal cutting means 113, 115 are provided for cutting each bag 10, illustrated in Figure 1, at the seal 44 to separate it from the continuous bag web 51.

As may be inferred from the above, the joins between the inner surfaces 51' of the bag are preferably made by heat-sealing. 5 A second preferred embodiment 100 of a bag is illustrated in Figure 9A. The bag of this second preferred embodiment is similar to that of the first embodiment, having components corresponding to those of the first embodiment, which are labelled with the same reference numerals and, for brevity, will not be described in detail again.

The bag of this second embodiment differs from the bag of the first embodiment in that there are means 134 for opening and closing the mouth, consisting, in particular, of a zip comprising a first fastening element 134a, on the front wall 12, and a second fastening element 134b, on the rear wall 14, that can be reciprocally engaged and disengaged.

The fastening elements 134a and 134b are supported by respective supporting elements or strips 136a, 136b, which are suitably joined, in particular sealed, at 183s and 183's, to respective inner faces 12' and 14' of the front and rear walls 12, 14, as shown in Figure 9B.

In particular, as illustrated, the closing means 134 comprise supporting elements or strips 136a, 136b, for the fastening elements 134a, 134b which are made in a single body with the respective element 134a, 134b and which comprise a single flange, or band, 136"a, 136"b, which relative to the fastening element 134a, 134b, faces the outside of the bag, that is to say, faces the direction opposite that of the bottom of the bag, i.e. the direction of product outflow from the bag.

Since the supporting means 136a, 136b for the fastening elements have this particular shape the zip can easily be opened. To open the zip, the user can simply insert his hand, pushing lengthways towards the bottom of the bag, with the flanges

136"a and 136"b guiding the hand towards the fastening elements 134a, 134b to open the zip.

This particular zip configuration also allows improved maintenance of the bag seal. Particles of material contained in the bag can get between the flanges 136"a and 136"b and the corresponding walls 12, 14 of the bag, promoting maintenance of the engagement between the fastening elements 134a and 134b.

Moreover, in this way a zip 134 which requires a minimum of material is obtained.

Advantageously, the means for sealing the end 56', 58' of the indented pleated portion 56, 58 consist of a first and a second short transversal sealing band 140a 140b, designed to seal off one end of a pleat.

As illustrated, the respective sealing band 140a, 140b designed, in the same way as the band 40, to seal off a respective end of an intended pleated portion 16', 18' is similar to the band 40 of the first preferred embodiment, differing only in that it is shorter 1' than the band 40.

The single band 140a, 140b preferably has an upper face 140' a, 140'b, a lower face 140" a, 140"b and can be sealed on both sides, being made for example of polythene.

The respective sealing band 140a, 140b, designed to seal off one end of a pleated portion, has a face 140"a, 140"b which engages with and is placed over the pleated end, to which it is sealed, and which engages with and is sealed to the rear wall 14 of the bag.

In practice, the sealing band 140a, 140b designed to seal off one end of the pleated portion engages with and is joined to the end of the pleat and to the wall 14 of the bag, being placed over the end of the pleat and holding it against the film face 54 opposite. In practice, the end of the pleat is held and sealed off between the sealing band 140a, 140b and part of the rear wall 14 of the bag.

The sealing band 140a, 140b also has a face 140'a, 140'b, opposite that engaging with and over the end of the pleat, said face being towards the front wall of the bag, to which it is sealed at said end and at the side of the bag. As illustrated in Figure 9A, the length 1' of the sealing band 140a, 140b designed to seal off one end of an indented pleated portion is slightly greater than the width of the pleat, and extends, over a predetermined stretch, longitudinally beyond the upper edge of the pleat.

In this way, as well as saving material for the sealing band, prolonged heating in the zone between the pleats is avoided, which avoids any bag deformations, the bag therefore being of better quality and having an appearance that is more attractive to consumers.

This second preferred embodiment of the bag 100 may advantageously be obtained using the same process previously described for the first preferred embodiment of the bag and which is not described again in detail.

The process for obtaining the embodiment of the bag 100 differs from that of the first preferred embodiment of the bag because, as illustrated in Figures 1OA, 1OB and from HA to HD, it comprises advantageous and specific means for applying the zip to the film, which advantageously comprise means 184 for positioning the zip 134 and means 183, 185 for joining, in particular sealing, at 183s an end, or flange, 136"a of the zip 134 to the film, or to the upper face of the film 51 which is made of heat-sealable material.

Advantageously, the sealing means 183, 185 are upstream of the zip 134 positioning means 184 relative to the direction of film feed "A". These joining means comprise a first and a second heated sealing bar 183,

185, which can move towards each other to clamp the zip 134 against the film 51 and seal a zip 134 flange 136"a to the film 51, and they can move away from each other to allow the film 51 feed movement.

In this way, as illustrated, the zip 134 flange 136"a seal is obtained which, relative to the position of the fastening elements 134a, 134b, in the finished bag extends towards the outside of the bag, that is to say, in the opposite direction to the bottom of the bag.

In practice, the means for positioning the zip 134 on the film 51 comprise means for feeding the zip transversally to the film 51, that is to say, transversally to the longitudinal edges of the film, said feed means comprising zip 134 supporting means 184, positioned above the film and extending transversally to it, that is to say, transversally to the longitudinal edges of the film, and zip 134 feed means 184' consisting of a plurality of feed rollers distributed along the supporting means 184 forming a guide 184a on which the zip can slide transversally.

The feed rollers 184' can move from the bottom upwards, as indicated by arrow H in Figure 1OB, to disengage the zip 134 and, after the lateral movement of the supporting plates 184, allow the zip to be drawn in the downstream direction by the film 51 being fed.

In particular, the zip supporting and holding means 184 form a zip sliding guide in the form of a recessed cavity 184a for fastening element 134a and 134b housing and sliding. Advantageously, the zip supporting means 184 can move between a position in which the zip is positioned close to the film 51, and a position in which they are distanced from the film and the zip 134 is free to pass downstream of the positioning zone, drawn by the film being fed.

In practice, advantageously, the zip 134 supporting means 184 can move, transversally, as indicated by the arrow B, to the film 51, between a zip positioning position, in which the supporting means are positioned above the portion of film 51 where the zip must be positioned, and a position offset relative to the zip applied, in particular to the side of the film, as may be inferred also from Figures 1 IA to 1 ID.

As illustrated, the zip 134 flanges 136"a and 136"b project upstream, beyond the transversal edge 184' of the holding support 184, which holds the zip 134 stationary while it is sealed to the film 51.

There are also means 184c for cutting the zip 134 from a tape of zip 179, not illustrated in detail in the drawings of the first preferred embodiment of the process.

The numerals 184", 184" denote feed rollers for the tape of zip 179. Advantageously, as illustrated, the zip 134 positioning means 184 can move away from and towards the longitudinal side or edge of the film 51 which is opposite that from which the zip is fed towards the film 51. As shown in Figure 12, this second preferred embodiment of the process also differs from the process of the first embodiment in that means for sealing the ends of the pleats are applied or provided on the film, the sealing means preferably consisting of a first and a second transversal band or strip 140a, 140b, preferably made of heat-sealable material, in particular heat-sealable on both sides or faces, designed to seal off one end of a pleat.

As illustrated, the length 1' of the sealing band 140a, 140b designed to seal off one end 16', 18' of an indented pleated portion 16, 18 is slightly greater than the width of the pleat. The sealing bands 140a, 140b consist of completely separate bands which are transversally distanced from each other.

Similarly to the first preferred embodiment of the process, the sealing bands 140a, 140b designed to seal off one end of the pleated portion engage with and are joined to the end of the pleat and to the film wall 54, being placed over the end of the pleat and so holding it against the film face 54 opposite. Figure 12 schematically illustrates advantageous means for positioning the respective transversal band 140a, 140b.

It will be understood, however, that these means may operate in any suitable manner, moving the band either transversally or perpendicularly to the film and allowing it to be cut to the required length 1' from a continuous web 171a, 171b unwound from a roll 173a, 173b. Obviously, a band 140a, 140b feeder designed to feed bands that have been pre-cut to the required length might also be used.

Advantageously, as illustrated the means 173a, 173b for applying the bands 140a, 140b are on the opposite sides of the film and move the bands 140a, 140b transversally to the film and in opposite directions to each other. As illustrated, the bands 140a, 140b are positioned in particular on the pleated portions in the folded condition, on a part 54 of the film 51 that will form the rear wall 14 of the bag and positioned over the end portions 56'b and 58'b of the upper pleated portions 56b, 58b.

To attach the transversal bands 140a, 140b to the film 51, suitable joining or sealing means 175, 177 positioned opposite each other, are used. They move vertically towards and against the film, and vice versa, in such manner as to seal the bands 140a, 140b, in particular the lower faces 140" a, 140"b, to the opposite upper face 51' of the film and to the portions 56'b, 58'b of the sections 56b, 58b of the V- shaped folded portions that will form the pleated portions 16 and 18 which are connected to the front wall 12 of the bag. In this way, the respective end 16', 18' of the pleated portions of the finished bag are sealed.

Advantageously, the sealing elements 175, 177 have, between the sealing ends 175', 175', 177', 177", a recessed portion 175a, 177a, which does not heat the 51 at all.

Each sealing band 140a, 140b has a main length "1", a height or width "h" and a first and a second opposite longitudinal faces, of which only one, labelled 5 140'a, 140'b, is evident in Figure 12. The respective band 140a, 140b also has a minimum thickness "t".

Each band 140a, 140b is sealed to the upper face 51' of the film and on top of the ends 56'b and 58'b of the pleats, so that part of the band remains on top of the pleats and part of the band is connected to the face 54 of the film at the margins of l o the pleats, thus sealing the ends of the pleats.

The strips or bands 140a, 140b may be made in any suitable way. For example they may consist of a single layer of polythene or similar material that can be sealed to the film the bag is made of, or they may consist of a layered material consisting of two layers, one layer of polythene and another layer for example of 15 polyester or other similar materials that can be sealed to the film the bag is made of, or in any other suitable way.

Since the respective band 140a, 140b can be sealed both by its lower face, which comes into contact with the film face 54, and by its upper face 140'a, 140'b, it is possible, as explained relative to the first embodiment, to seal its upper face 20 140'a, 140'b to the corresponding film face 52 at the lateral ends 140c, 14Od of the band 140a, 140b, thereby imparting added strength to the assembly at these lateral zones.

In a third preferred embodiment, illustrated in Figure 13, there are also third zip positioning means.

25 In practice, the third embodiment of the means for positioning the zip on the film comprise means 284 for supporting and feeding the zip transversally to the film 51, that is to say, transversally to the longitudinal edges of the film, which are designed to engage the zip 134 at a plurality of points along its length, these means consisting of gripper means for gripping and releasing the zip. For this purpose, the 30 gripper means comprise a first and a second jaw 284'a and 284"a positioned opposite each other, which can move between a position in which they are spread apart and do not hold onto but instead release the zip 134 and a position in which they are close to each other and hold onto the zip 134.

At the zip 134 positioning zone, the gripper means 284 can move between a 35 raised position and a lowered position on the film, in which they position the zip in contact with the film.

As shown in Figure 13, the film moves in the direction indicated by the arrow A and the numerals 283, 285 denote the bars for sealing the zip to the film.

The zip supporting means 284 can also move transversally, as indicated by the arrow B, between a zip positioning position, close to the film 51, and a position in which they are distanced from the zip positioning and gripping position. In a fourth preferred embodiment, illustrated in Figure 14, there are also fourth zip positioning means, which are similar to the third positioning means.

In practice, the means for positioning the zip on the film comprise means

284 for supporting and feeding the zip transversally to the film 51, that is to say, transversally to the longitudinal edges of the film, which are designed to engage the zip 134 at a plurality of points along its length, these means consisting of gripper means for gripping and releasing the zip. For this purpose, the gripper means comprise a first and a second jaw 284'a and 284a positioned opposite each other, which can move between a position in which they are spread apart and do not hold onto but instead release the zip 134 and a position in which they are close to each other and hold onto the zip 134.

At the zip 134 positioning zone, the gripper means 284 can move between a raised position and a lowered position on the film, in which they position the zip in contact with the film.

In this fourth embodiment the film moves according to the direction indicated by the arrow A and the zip positioning grippers are positioned downstream of the zip 134 and downstream of the sealing means 283, 285.

In this fourth preferred embodiment, the gripper means 284 can also move between a position for positioning the zip 134 on the film 51 and a position distanced from the film to allow the passage of the portion of film with the zip 134 longitudinally beyond the gripper means. For this purpose, the gripper means can rotate, as indicated by the arrow R, relative to a parallel axis transversal to the film.

The zip supporting means 284 can also move transversally, as indicated by the arrow B, between a zip positioning position, close to the film, and a position in which they are distanced from the zip positioning and gripping position. Figure 15 illustrates a fifth preferred embodiment of the process and apparatus for making a bag.

The process and apparatus of this fifth preferred embodiment is similar to that of the first and second preferred embodiments, having steps and components corresponding to those of the previous embodiments, labelled with the same reference numerals and, for brevity, not described in detail again.

This fifth preferred embodiment differs from the previous embodiments in that a part 56'a, 58'a of the portion, or flap, 56a, 58a of the pleat is joined to a part 546a, 548a of the film face 54 opposite with an oblique connecting strip 156's, 158' s extending from an edge of the pleat facing the inside of the film, in particular from the inner end 56', 58'e of the transversal joining strip 56's, 58's towards and as far as the opposite edge 54a, 54b of the pleated portion. In practice, this join 156's, 158's consists of a straight strip, set at an angle to the respective transversal joining strip 56's, 58's.

In practice, these oblique joins 156's, 158's extend in such a way that they converge upstream, relative to the direction of film feed, that is to say, towards the mouth or the upper part of the bag. The respective join 156's, 158's extends from the upper edge, or upstream, and inside the pleat set at an angle to the longitudinal direction of film feed until it reaches the outer lateral edge of the pleat.

In the finished bag, this oblique join 156's, 158's prevents the material contained in the bag from entering the upper zone between the flaps 21 and 25 of the pleats and the corresponding inner face of the rear wall 14 of the bag, getting stuck there and causing a problem.

Said oblique seals 156's, 158's may also advantageously be made simultaneously with the transversal stabilising seals 56's, 58's, in particular, by the same sealing means when they are suitably shaped. It would also be possible to use only the oblique seals 156's, 158's as stabilising joins in place of the transversal seals 56's and 58's.

Figure 16 illustrates a sixth preferred embodiment of the process and apparatus for making bags.

The process and apparatus of this sixth preferred embodiment is similar to that of the second embodiment, having steps and components corresponding to those of the second embodiment, which are labelled with the same reference numerals and, for brevity, are not described again in detail.

The process and apparatus of this sixth preferred embodiment only differs from the second preferred embodiment in that means for sealing the ends of the pleats are applied or provided on the film, the sealing means preferably consisting of a first and a second transversal strip or band 140a, 140b, positioned one after the other, in two different stations longitudinally distanced from each other and, in any case, adjacent to each other.

In practice, unlike what is shown in Figure 12, as illustrated in Figure 16, there is a first and a second transversal band or strip 140a, 140b, preferably made of heat-sealable material, in particular heat-sealable on both sides or faces, the bands being designed to seal off one end 16', 18' of a pleat, the bands 140a, 140b of material being cut to the desired length from a respective web 171a, 171b unwound from rolls 173a, 173b, located at the longitudinal side or edge 51b of the film 51, with the bands 140a, 140b moving transversally to the film 51 and in the same direction. 5 Obviously, as illustrated, the distance covered by the band 140a is longer than that covered by the band 140b.

As illustrated, according to the direction A of film 51 feed, the band 140a is placed on the film 51, in a longitudinally upstream position, or before the band 140b is applied. Obviously, it would also be possible for the band 140a to be placed on the l o film 51 in a downstream position, or after application of the band 140b.

Moreover, advantageously, the rolls 173a, 173b from which a sealing band

140a, 140b is taken are located on the side of the film 51 corresponding to the side immediately adjacent to the zone of the film where the pleats are made, or at least the pleat 58a, 58b. 15 According to another embodiment, it would also be possible for the rolls

173 a, 173b to be located on the opposite side 51a of the film 51.

To attach the transversal bands 140a, 140b to the film 51, suitable joining or sealing means 175a, 177a and 175b, 177b positioned opposite each other are used.

They move vertically towards and against the film, and vice versa, in such manner as 20 to seal the bands 140a, 140b, in particular the lower faces, to the opposite upper face

51' of the film and to the portions 56'b, 58'b of the sections 56b, 58b of the V- shaped folded portions that will form the pleated portions 16 and 18 which are connected to the front wall 12 of the bag. In this way, the respective end 16', 18' of the pleated portions of the finished bag is sealed. 25 Advantageously, the sealing elements 175a, 177a and 175b, 177b have sealing ends 175', 177' which project perpendicularly.

As illustrated, the first means 175a, 177a for sealing the pleat sealing band

140a are located in a position longitudinally upstream of the second means 175b,

177b for sealing the respective pleat sealing band 140b. 30 Figure 17 illustrates a seventh preferred embodiment of the process and apparatus for making bags.

The process and apparatus of this seventh preferred embodiment is similar to that of the second and sixth embodiments, having steps and components corresponding to those of the second and sixth embodiments, which are labelled 35 with the same reference numerals and, for brevity, are not described again in detail. The process and apparatus of this seventh preferred embodiment, as for the sixth embodiment, involves applying or providing means for sealing the ends of the pleats on the film, the sealing means preferably consisting of a first and a second transversal strip or band 140a, 140b, provided one after the other, in two stations which are longitudinally distanced from each other.

In this seventh preferred embodiment, unlike the sixth preferred embodiment, the pleat sealing bands 140a, 140b, cut to the desired length from a respective web 171a, 171b, unwound from suitable rolls 173a, 173b, are positioned on opposite longitudinal sides or edges 51a, 51b of the film, with the bands 140a,

140b moving transversally to the film and in opposite directions.

In this seventh preferred embodiment, again, as illustrated, according to the direction A of film 51 feed, the band 140a is placed on the film 51, in a longitudinally upstream position, or before the band 140b is applied. Obviously, it would also be possible for the band 140a to be placed on the film 51 in a downstream position, or after application of the band 140b.

Both the sixth and seventh embodiments offer respective advantages for operators and for the specific positioning of the corresponding device.

Figures 18A to 18D and 19 illustrate a device which can be used in particular in an apparatus for making bags, for applying pleat end sealing bands 140a, 140b.

The device implements an eighth preferred embodiment of the process, similar to that of the second embodiment, having steps and components corresponding to those of the second embodiment, which are labelled with the same reference numerals and, for brevity, are not described again in detail.

The device comprises, in particular, first and second means 310, 311 for applying respective sealing bands 140a, 140b to the film 51, at the respective longitudinal portion, designed to form the pleats.

The device is supported on a shared supporting frame 313, which supports the transversally aligned application means 310, 311.

The result is a compact device, allowing an apparatus to be obtained which has a reduced length and is easy to install even in existing apparatuses. The frame 313 comprises lateral plates 313a, 313b, which can be connected to the frame of the apparatus for making the bag, in which this device is inserted, and has upper crosspieces 313c, extending between the lateral plates, or uprights, 313a, 313b and which support other plates that support device components, in particular supporting a central horizontal upper plate 313d for the device's sealing means.

As shown in Figure 19, respective elements or plates 313e, 313e of the frame 313 are supported by the respective rolls 373, 373, from which a web of material 371, 371 is unwound to make a sealing band 140a, 140b for the end of the pleat.

As illustrated, the band web 371 goes around return rollers 375 and through an opening 377 made in the respective plate or upright 313a, 313b, the web 317 entering the central operating part of the device towards the film 51.

As illustrated, the rolls 373, 373 are supported on opposite sides of the device and the film, in particular on the outside of and by the plates or uprights 313a, 313b, making them very easy to substitute.

Advantageously, the first and second means 310, 311 for applying the respective sealing band 140a, 140b operate simultaneously with each other.

Each of the application means 310, 311 comprises respective means 320 for holding, or releasing, the band web 371, not illustrated in Figure 19 and consisting of a gripper 320, having a first and a second jaw for gripping and releasing the band web 371, the jaws extending parallel with the film 51 and trans versally to the direction of the feed of the band web 371.

The means for holding and releasing the band web 371 are fixed to the frame 313.

When open, the holding and releasing gripper 320 allows the passage of the web 371 towards the zone for application of the respective band 140a, 140b to the bag film 51.

When closed, the holding and releasing gripper 320 grips and firmly holds the band web 371 during separation and application of the sealing band 340a, 340b on the film 51.

To move the jaws of the gripper 320 of each operating unit 310, 311 there is a pneumatic cylinder, not illustrated in detail in the accompanying drawings.

In practice, the upper jaw of the gripper 320 moves perpendicularly to the band web 371, between a raised position allowing the web free passage and a lowered position in which it engages with the band web 371 and stops it from sliding. The means 310, 311 for applying the sealing bands to the film also comprise respective band web 371 feed means 312.

The band web 371 feed means 310 can move transversally to the bag film 51 and consist of a gripper 312, having a first and a second jaw for gripping the band web. As can be inferred from Figures 18A and 18B, the band web 371 feed means 312 can move between a gripping position, illustrated in Figure 18 A, and a position in which they release the band web 371, illustrated in Figure 18B. Said feed stroke, and subsequent return to the position in Figure 18 A, by the film feed gripper 312 is controlled by a pneumatic cylinder 312', which drives a rod 312", supporting equipment with another cylinder for driving the gripper 312, illustrated in detail in Figure 20, and a vertical cylinder 314' for driving cutting means 314 forward movement, schematically illustrated in Figures 18A to 18D with a dashed line.

The cutting means 314 also move transversally to the film 51, simultaneously and together with the feed gripper 312, as illustrated in Figures 18A to 18D. The means 310, 311 for applying the respective band 140a, 140b therefore comprise means 314 for cutting the band 340a, 340b from the band web 371, the cutting means cutting the web 371 after the feed gripper 312 has performed a feed stroke.

Following the cut, the equipment consisting of the feed gripper 312 and the cutting means 314 returns to the back, starting position in Figure 18 A.

The feed gripper 312 transversal stroke, forward and backward, has a length matching the length 1' of the sealing band 140a, 140b. In practice, the feed means 312 and the cutting means 314 form means for forming the respective sealing band 140a, 140b As is schematically illustrated, the means for cutting the sealing band

140a, 140b comprise blade means 314, extending longitudinally or according to the direction of film 51 feed or positioned transversally relative to the band web 371.

The blade 314 moves perpendicularly to the band web 371, between a raised position allowing the web free passage and a lowered position in which it cuts the band web 371.

As indicated, the band cutting means 314 move transversally to the film 51 between a retracted position and a forward position for cutting the band 340a, 340b from the respective band web 371. As indicated, the means 314 for cutting the band 340a, 340b move together with the band web 371 means and cut the band in the position in which the feed means 312 have released the band web 371 to the means 316, consisting of a gripper with jaws for gripping the band, in the operating condition illustrated in Figure 18B. As indicated, the sealing band application means 310, 311 comprise means

316 for positioning the sealing band at the respective pleated portion of the bag film 51. The positioning means 316 grip the band web, receiving it from the feed means 312, and, after cutting a sealing band 140a, 140b from the web, position the band 140a, 140b on the film 51, below suitable sealing means 318, described in more detail below and as illustrated in Figure 18D. The band 140a, 140b positioning means 316 also move trans versally to the film 51, between a position in which they grip the band 140a, 140b, illustrated in Figures 18A and 18B, and a position in which they release the band 140a, 140b at the respective predetermined position on the film 51 illustrated in Figures 18C and 18D. In particular, the band 140a, 140b positioning means 316 move vertically, or perpendicularly to the film 51, to bring the respective band to the film and vice versa to move away from the film once the band has been transferred to the film 51, thus returning to the back position to grip a new band to be applied.

In particular, the band positioning grippers 316 of the device 312, 311 are supported by a shared plate 316', moved by vertical cylinders 316", 316", to perform a perpendicular movement towards and away from the film 51, to respectively carry the band to the film and then move away from the film 51.

In particular, the band positioning means 316 move between a raised position for gripping the band 140a, 140b and a lowered position for transferring the 140a, 140b to the film 51.

The numeral 316'" denotes horizontal cylinders, extending transversally, driving the transversal movement or stroke of the band positioning means 316.

As can be inferred from Figures 18A and 18B, in particular, the feed means 312 grip the band web 371, holding it along a respective lateral edge, or portion, and the band positioning means 316 grip a band web 371 at the lateral edge or portion opposite that gripped by the feed means 312.

The application means 310, 311 also comprise means 318 for sealing the band 140a, 140b to the bag film 51.

The means 318 for sealing the band 140a, 140b operate on the side or portion of the sealing band 140a, 140b opposite that held by the band positioning means 316.

In particular, the band positioning means 316 hold the band 140a, 140b, engaging a minimum transversal stretch of it, in particular a transversal part of the band 140a, 140b which is less than half the width of the band 140a, 140b. In practice, the band positioning gripper 316 holds the sealing band 140a,

140b by a stretch substantially two millimetres wide.

The numeral 318' denotes a cylinder, or actuator, for moving the sealing plates 318 of the first and second application means 310, 311.

The band sealing step is illustrated in Figure 18D. In this step the band feed means 312, and the corresponding cutting means 314, return towards the starting position where they grip the band web 371. During this return stroke by the band feed means 312 and the cutting means 314, the fixed gripper 320 for gripping and releasing the band web 371 is in the closed condition, meaning that the web band 371 is held stationary, with the possibility of the band web sliding between the jaws of the band feed gripper 312 without any problems. Once the sealing means 318 have engaged with the band 140a, 140b, the band positioning means 316 return to the starting position shown in Figure 18 A.

Figure 20 shows the band feed gripper 312 and the positioning gripper 316 alongside each other, the former transferring the band web 371 to the latter. As illustrated, each gripper has an upper jaw 312a, 314a and a lower jaw 312b, 314b, between which the band web 371 or film is held.

The numerals 312'", 314'" denote the cylinders for driving the grippers 312, 314.

It shall be understood that the claims herein disclose additional and respective preferred embodiments of the invention and, through this reference, they shall be considered an integral part of this description of preferred embodiments of the invention.

The invention described above is susceptible of industrial application and may be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements. It shall also be understood that it would also be possible to have preferred embodiments that are similar to the preferred embodiments described above and in which, however, corresponding steps, means or components described above could be omitted.

Claims

1. A process for making bags (50), in which a film (51), preferably a plastic film, in particular a flexible plastic film, is fed and in said film (51) at least one indented pleated portion is made, in particular a first and a second indented pleated portions (56, 58); characterised in that a corresponding part (56' a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite.

2. The process according to claim 1, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before the film (12) is made into a tube.

3. The process according to either of the foregoing claims, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite immediately downstream of the zone for forming the pleats (56, 58).

4. The process according to any of the foregoing claims or according to the preamble to claim 1, characterised in that pleat sealing means (40, 140a, 140b) are attached to the film.

5. The process according to claim 4, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before the pleat sealing means (40) are attached to the film.

6. The process according to any of the foregoing claims or according to the preamble to claim 1, characterised in that bag opening and closing means (34, 134) are attached to the film.

7. The process according to claim 6, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before the bag opening and closing means (34) are attached to the film.

8. The process according to any of the foregoing claims or according to the preamble to claim 1, characterised in that a transversal seal (44) is made, which will form the bottom of the bag.

5

9. The process according to claim 8, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before the transversal seal (44) which will form the bottom of the bag is made. 0

10. The process according to any of the foregoing claims or according to the preamble to claim 1, characterised in that it involves sealing the longitudinal edge (43, 45, 47, 49) of the respective pleat (56, 58). 5

11. The process according to claim 10, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before sealing the longitudinal edge of the respective pleat. 0

12. The process according to claim 10 or 11, characterised in that the longitudinal edge (43, 45) of the respective pleat is sealed before making the film (12) into a tube and/or before attaching the pleat sealing means (40) to the film, and/or before attaching the bag opening/closing means (34) to the film, and/or before making the transversal seal (44) which will form the bottom of the bag.5

13. The process according to any of the foregoing claims, characterised in that a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite before part of the longitudinal edge of the respective pleat is o trimmed.

14. The process according to any of the foregoing claims, characterised in that a corresponding end (56'a, 58'a or 56"a, or 58"a) of the respective pleated portion (56a, 58a) is joined to a corresponding part (546a, 548a or 546b, 548b) of the film 5 face (51') opposite.

15. The process according to any of the foregoing claims or according to the preamble to claim 1, characterised in that opposite openings (55, 57) are made in the film at a corresponding portion of film forming the indented pleated portion.

5 16. The process according to claim 15, characterised in that the join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite is made after openings (55, 57) forming the mouth of the corresponding bag have been made in the film. 0

17. The process according to any of the foregoing claims, characterised in that opposite longitudinal ends (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) delimited by successive openings (55, 55, 57, 57) are joined to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite. 5

18. The process according to any of the foregoing claims, characterised in that said join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite extends transversally. 0

19. The process according to claim 18, characterised in that said join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite extends transversally across the full width of the pleat. 5

20. The process according to any of the foregoing claims, characterised in that, at the join between a corresponding part (56"a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546b, 548b) of the film face (51') opposite, the transversal seal (44) which will form the bottom of the respective o bags is made.

21. The process according to any of the foregoing claims, characterised in that said join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of 5 the film face (51') opposite extends obliquely.

22. The process according to claim 21, characterised in that said join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite extends obliquely from an inner end of the pleat to the outer end or edge of it.

23. The process according to any of the foregoing claims from 4 to 22, characterised in that the means for sealing the corresponding end (56', 58') of the indented pleated portion (56, 58) consist of a respective sealing band (40).

24. The process according to any of the foregoing claims from 4 to 23, characterised in that the means for sealing the corresponding end (56', 58') of the indented pleated portion (56, 58) consist of a respective short sealing band (140a or 140b) designed to seal off a corresponding end of a corresponding pleat.

25. The process according to claim 24, characterised in that the means for sealing the corresponding end (56', 58') of the indented pleated portion (56, 58) comprise a respective second short sealing band (140a, 140b) designed to seal off a corresponding end of a corresponding indented pleated portion.

26. The process according to any of the foregoing claims from 22 to 25, characterised in that the length of the sealing band (140a, 140b) designed to seal off a corresponding end of a corresponding indented pleated portion is slightly greater than the width of the respective bag.

27. The process according to claim 25 or 26, characterised in that separate sealing bands (140a, 140b) are applied (173, 173b) simultaneously or one after another.

28. The process according to any of the foregoing claims from 4 to 27, characterised in that the sealing band (40, 140a, 140b) consists of a band of material which is heat-sealable on both faces.

29. The process according to any of the foregoing claims from 4 to 28, characterised in that a respective longitudinal end (56', 58') of the respective indented pleated portion (56, 58) is sealed off using respective sealing means before the film (51) is made into a tube.

30. The process according to any of the foregoing claims from 4 to 29, characterised in that means for sealing the corresponding end of the pleated portion (56', 58') are applied to the film after the respective pleated portion (56a,

5 56b, 58a, 58b) has been formed.

31. The process according to any of the foregoing claims, characterised in that the sealing band (14, 140a, 140b) for the corresponding end of the pleat is placed over said end of the pleat, holding it against the film face 54 opposite. 0

32. The process according to any of the foregoing claims from 6 to 31, characterised in that the closing means (34) are attached to the film at the film outer face (52) transversally to the openings (55, 57). 5

33. The process according to any of the foregoing claims from 6 to 32, characterised in that the closing means (34) are attached to the film immediately downstream of the zone where the pleat sealing band (40, 140a, 140b) is attached.

34. The process according to any of the foregoing claims from 6 to 33, o characterised in that the closing means (34) are of the type having elements that can reciprocally be engaged and disengaged and are applied to the film with the elements that can be engaged and disengaged in the fastened condition.

35. The process according to any of the foregoing claims from 6 to 34,5 characterised in that the pleat sealing means (40, 140a, 140b) and the closing means which can open and close (34) are arranged in such a way that they are longitudinally distanced from each other.

36. An apparatus for making bags (50), where means are provided for feeding a0 film (51), preferably a plastic film, in particular a flexible plastic film, and means designed to make at least one indented pleated portion in the film (51), in particular a first and a second indented pleated portions (56, 58); the apparatus being characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a 5 corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite.

37. The apparatus according to claim 36, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the zone in which the film is made into a tube.

38. The apparatus according claim 36 or 37, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located immediately downstream of the zone for forming the pleats (56, 58).

39. The apparatus according to any of the foregoing claims from 36 to 38 or according to the preamble to claim 36, characterised in that it comprises means for providing pleat sealing means.

40. The apparatus according to claim 39, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the means for providing the pleat sealing means on the film.

41. The apparatus according to any of the foregoing claims from 36 to 40 or according to the preamble to claim 36, characterised in that it comprises means for attaching bag opening and closing means (34) to the film.

42. The apparatus according to claim 41, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the means for attaching the bag opening and closing means (34) to the film.

43. The apparatus according to any of the foregoing claims from 36 to 42 or according to the preamble to claim 36, characterised in that it comprises means for making a transversal seal (44) which will form the bottom of the bag.

44. The apparatus according to claim 43, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the means

5 for making the transversal seal (44) which will form the bottom of the bag.

45. The apparatus according to any of the foregoing claims from 36 to 44 or according to the preamble to claim 36, characterised in that it comprises means for sealing the longitudinal edge (43, 45, 47, 49) of the respective pleat (56, 58). 0

46. The apparatus according to claim 45, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the means5 for sealing the longitudinal edge of the respective pleat.

47. The apparatus according to claim 45 or 46, characterised in that the means for sealing the longitudinal edges (43, 45) of the respective pleats are located upstream of the means for making the film 12 into a tube, and/or upstream of the0 means for attaching the pleat sealing means (40) to the film, and/or upstream of the means for attaching bag opening and closing means (34) to the film, and/or upstream of means for making the transversal seal (44) which will form the bottom of the bag. 5

48. The apparatus according to any of the foregoing claims from 36 to 47, characterised in that it comprises means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, said joining means being located upstream of the means for trimming part of the longitudinal edge of o the respective pleat.

49. The apparatus according to any of the foregoing claims from 36 to 48, characterised in that it comprises means for joining a corresponding end (56'a, 58'a or 56"a or 58"a) of the respective pleated portion (56a, 58a) to a5 corresponding part (546a, 548a or 546b, 548b) of the film face (51') opposite.

50. The apparatus according to any of the foregoing claims from 36 to 49, characterised in that it comprises means for joining opposite longitudinal ends (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) delimited by successive openings (55, 55, 57, 57) to a corresponding part (546a, 546b, 548a,

5 548b) of the film face (51') opposite.

51. The apparatus according to any of the foregoing claims from 36 to 50, characterised in that said joining means are designed to join a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a0 corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, the seal extending transversally.

52. The apparatus according to claim 51, characterised in that said joining means are designed to join a corresponding part (56'a, 56"a, 58'a, 58"a) of the5 respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, the seal extending transversally across the full width of the pleat.

53. The apparatus according to any of the foregoing claims from 36 to 52, o characterised in that the means designed to make the transversal seal (44) that will form the bottom of the respective bags make said transversal seal at the join between a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite. 5

54. The apparatus according to any of the foregoing claims from 37 to 53, characterised in that said joining means are designed to join a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite, the0 seal extending obliquely.

55. The apparatus according to claim 54, characterised in that the joining means are designed to join a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) and a corresponding part (546a, 546b, 548a, 548b) of5 the film face (51') opposite, the seal extending obliquely from an inner end of the pleat to the outer end or edge of it.

56. The apparatus according to any of the foregoing claims from 36 to 57 or according to the preamble to claim 36, characterised in that it comprises means designed to make opposite openings (55, 57) in the film at a corresponding portion of film forming the indented pleated portion.

57. The apparatus according to claim 56, characterised in that the means for joining a corresponding part (56'a, 56"a, 58'a, 58"a) of the respective pleated portion (56a, 58a) to a corresponding part (546a, 546b, 548a, 548b) of the film face (51') opposite are located downstream of the means for making the openings (55, 57) forming the mouth of the corresponding bag.

58. The apparatus according to any of the foregoing claims from 39 to 57, characterised in that the means for providing means for sealing the corresponding end (56', 58') of the pleated portion (56, 58) on the film consist of means designed to apply sealing bands to the film.

59. The apparatus according to claim 58, characterised in that the means for applying the means for sealing the corresponding end (56', 58') of the indented pleated portion (56, 58) consist of means designed to apply a respective first and second sealing band (140a, 140b) on respective pleated portions (56, 58) which are transversally aligned with each other.

60. The apparatus according to claim 58 or 59, characterised in that it comprises first and second means (310, 311) for applying the respective sealing bands (140a, 140b) for corresponding pleated portions.

61. The apparatus according to any of the foregoing claims from 58 to 60, characterised in that the means (173a, 173b) for applying the sealing bands (140a, 140b) are on opposite sides of the film.

62. The apparatus according to claim 60 or 61, characterised in that the means (173a, 173b) for applying the sealing bands (140a, 140b) are on the same side of the film.

63. The apparatus according to claim 61 or 62, characterised in that the means (173a, 173b) for applying the sealing bands (140a, 140b) are longitudinally distanced from each other.

64. The apparatus according to any of the foregoing claims from 36 to 63, characterised in that it comprises means for sealing off a respective longitudinal end (56', 58') of the respective indented pleated portion (56, 58) using respective sealing means (52) before the film (51) is made into a tube.

65. The apparatus according to any of the foregoing claims from 58 to 64, characterised in that the means for applying to the film means (40, 140a, 140b) for sealing the corresponding end of the pleated portion (56', 58') are located downstream of the means for forming the respective pleated portion (56a, 56b, 58a, 58b).

66. The apparatus according to any of the foregoing claims from 36 to 65, characterised in that it comprises means for transversally separating the film at the bottom join, in such a manner as to form the bottom of one bag and the mouth of the next bag.

67. The apparatus according to any of the foregoing claims from 41 to 66, characterised in that the means for attaching the closing means (34) attach the closing means to the film at the film face (52) which is outside the openings (55, 57).

68. The apparatus according to any of the foregoing claims from 41 to 67, characterised in that the means for attaching the closing means (34, 134) are located immediately downstream of the zone where the pleat sealing band (40, 140a, 140b) is attached.

69. The apparatus according to any of the foregoing claims from 41 to 68, characterised in that the means for attaching the closing means (34, 134) apply closing means (34, 134) of the type with fastening elements which are attached to the film in the fastened condition.

70. The apparatus according to any of the foregoing claims from 41 to 69, characterised in that the pleat sealing means (40) and the closing means (34) which can open and close are arranged on the film in such a way that they are longitudinally distanced from each other.

71. The apparatus according to any of the foregoing claims from 41 to 70, characterised in that the means for applying the bag closing means to the film comprise means (84, 184, 284) for positioning the bag closing means and means (83, 85, 183, 185, 283, 285) for joining the bag closing means to the film.

5

72. The apparatus according to any of the foregoing claims from 41 to 71, characterised in that the means (183, 185) for joining the bag closing means are positioned upstream of the means (184) for positioning the bag closing means. 0

73. The apparatus according to any of the foregoing claims from 41 to 72, characterised in that the means (184) for supporting the bag closing means can move between a position in which they position the bag closing means close to the film (51), and a position distanced from the film and allowing the bag closing means (134) to pass freely downstream of the positioning zone. 5

74. The apparatus according to claim 73, characterised in that the means (184) for positioning the bag closing means can move in a direction opposite to that from which the bag closing means (134) are fed. 0

75. The apparatus according to any of the foregoing claims from 41 to 74, characterised in that the means for positioning the bag closing means on the film comprise means (284) for supporting and feeding the bag closing means.

76. The apparatus according to claim 75, characterised in that the means (284)5 for supporting and feeding the bag closing means consist of gripper means (284',

284") for gripping and releasing the bag closing means.

77. The apparatus according to any of the foregoing claims from 58 to 76, characterised in that it comprises a supporting frame (313) for first and second o means (310, 311) for applying respective sealing bands (140a, 140b) for respective transversally aligned ends of respective pleats.

78. The apparatus according to any of the foregoing claims from 58 to 77, characterised in that the application means (310, 311) comprise respective means 5 (320) for holding and releasing the band web (371).

79. The apparatus according to claim 78, characterised in that the means (320) for holding and releasing the band web are fixed to the respective supporting frame.

80. The apparatus according to claim 78 or 79, characterised in that the means for holding and releasing the band web comprise a gripper (320) having respective first and second jaws for gripping and releasing the band web (371).

81. The apparatus according to any of the foregoing claims from 58 to 80, characterised in that the application means (310, 311) comprise respective band web (371) feed means (312).

82. The apparatus according to claim 81, characterised in that the band web feed means (312) can move transversally to the film (51).

83. The apparatus according to claim 81 or 82, characterised in that the band web feed means comprise a gripper (312) having respective first and second jaws for gripping and releasing the band web.

84. The apparatus according to any of the foregoing claims from 81 to 83, characterised in that the band web (371) feed means (312) can move between a position in which they grip the band web and a position in which they release it.

85. The apparatus according to any of the foregoing claims from 58 to 84, characterised in that the application means comprise means (314) for cutting the band (140a, 140b) from the band web (371).

86. The apparatus according to claim 85, characterised in that the means (314) for cutting the band (140a, 140b) comprise blade means extending in the direction of film (51) feed.

87. The apparatus according to claim 85 or 86, characterised in that the means (314) for cutting the band (140a, 140b) can move transversally to the film (51).

88. The apparatus according to any of the foregoing claims from 85 to 87, characterised in that the cutting means (314) can move between a position in which they are retracted and a forward position in which they cut the band (140a, 140b).

89. The apparatus according to any of the foregoing claims from 85 to 88, characterised in that the means (314) for cutting the band (140a, 140b) move together with the band web (371) feed means (312).

90. The apparatus according to any of the foregoing claims from 85 to 89, characterised in that the means (314) for cutting the band (140a, 140b) make the cut while the band web (371) feed means (312) are in the band web released position.

91. The apparatus according to any of the foregoing claims from 58 to 90, characterised in that the application means (310, 311) comprise means (316) for positioning the sealing band (140a, 140b) on the film (51).

92. The apparatus according to claim 91, characterised in that the means (316) for positioning the band (140a, 140b) can move transversally to the film (51).

93. The apparatus according to claim 91 or 92, characterised in that the means for positioning the band (140a, 140b) comprise a gripper (316) having respective first and second jaws for gripping and releasing the band web.

94. The apparatus according to any of the foregoing claims from 91 to 93, characterised in that the means (316) for positioning the band can move between a position in which they grip the band and a position in which they release the band (140a, 140b).

95. The apparatus according to any of the foregoing claims from 91 to 94, characterised in that the means (316) for positioning the band (140a, 140b) can move perpendicularly to the film (51).

96. The apparatus according to any of the foregoing claims from 81 to 95, characterised in that the band web feed means (312) grip the band web (371), holding it along a respective lateral edge or portion.

97. The apparatus according to any of the foregoing claims from 91 to 96, characterised in that the positioning means (316) grip the band web (371) at a lateral edge or portion.

98. The apparatus according to claim 97, characterised in that the positioning means (316) grip the band web (371) at a lateral edge or portion which is opposite the lateral edge or portion gripped by the feed means (312).

99. The apparatus according to any of the foregoing claims from 58 to 98, characterised in that the application means (310, 311) comprise means (318) for sealing the band (140a, 140b) to the film (51).

100. The apparatus according to claim 99, characterised in that the means (318) for sealing the band (140a, 140b) to the film (51) engage with the band (140a, 140b) immediately after the positioning means (316) rest the band on the film (51).

101. The apparatus according to claim 99 or 100, characterised in that the means (318) for sealing the band to the film (51) for the bag engage with the band (140a, 140b) on the lateral edge or portion which is opposite that held by the positioning means (316).

102. The apparatus according to any of the foregoing claims from 97 to 101, characterised in that the positioning means (316) hold the band (140a, 140b) over a minimum stretch which is less than half the width of the band.

103. A bag (100), preferably made of plastic film, in particular flexible plastic film, comprising a front wall (12), a rear wall (14) and at least one corresponding indented pleated portion, in particular a first and a second indented pleated portions (16, 18) on opposite sides (16, 18) of the bag, characterised in that it comprises means for sealing the corresponding end of the pleated portion, consisting of a respective sealing band (140a, 140b).

104. The bag according to claim 103, characterised in that the means for sealing the corresponding end (16', 18') of the pleated portion (58) comprise respective first and second sealing bands (140a, 140b) designed to seal off respective ends of corresponding pleated portions.

105. The bag according to claim 103 or 104, characterised in that the length of the sealing band (140a, 140b) designed to seal off a corresponding end of a corresponding pleated portion is slightly greater than the width of the respective pleat.

106. The bag according to any of the foregoing claims from 103 to 105, characterised in that the sealing band (140a, 140b) designed to seal off a corresponding end of the pleated portion engages with and is joined to the respective end of the pleat and to the corresponding wall (14) of the bag.

107. The bag according to any of the foregoing claims from 103 to 106, characterised in that the sealing band (140a, 140b) designed to seal off a corresponding end of a corresponding pleated portion has an opposite face to that which engages with the respective end of the pleat and can be sealed on both the engaging face and the opposite face.

108. The bag according to any of the foregoing claims from 103 to 107 or according to the preamble to claim 103, characterised in that it comprises means (134) for opening and closing an opening which allows product outflow from the bag.

109. The bag according to claim 108, characterised in that the means (134) for opening and closing the opening comprise a first and a second fastening element (134a, 134b) supported by respective supporting flanges (136'a, 136'b) which can be fixed to the respective wall (12, 14) of the bag; and also being characterised in that the supporting flanges extend relative to the fastening elements (134a, 134b) towards the outside of the bag.

110. The bag characterised in that it is made in accordance with the process according to any of the foregoing claims from 1 to 35.

111. A film for making bags characterised in that it is made according to the process of any of the claims from 1 to 35.

112. A bag web characterised in that it is made according to the process of any of the claims from 1 to 35.