AU743057B2 - A machine and a method for automatically forming, filling, and closing bags - Google Patents

Description

1- P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title:

FLEXICO-FRANCE

Henri BOIS CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia A MACHINE AND A METHOD FOR AUTOMATICALLY FORMING, FILLING, AND CLOSING BAGS The following statement is a full description of this invention, including the best method of performing it known to us

IA

A MACHINE AND A METHOD FOR AUTOMATICALLY FORMING, FILLING, AND CLOSING BAGS The present invention relates to machines for automatically forming, filling, and closing packages based on film, in particular of thermoplastic material, and including closure ribs, e.g. complementary male and female closure ribs.

Such machines are often known as "Form, Fill, and Seal machines" or FFS machines.

Numerous machines of this type have already been proposed.

Most such machines comprise: 009. 1 a former which is fed with film in the plane state 15 coming from a pay-out spool and which delivers the film shaped into a tube; a filler chute opening out into said oo o former and consequently into said tube; longitudinal sealing means for closing the tube longitudinally; and 20 means suitable for generating sequentially a first transverse line of sealing before any product is put into the tube via the filling chute, and then a second transverse line of sealing when product has been put into the tube, to close a package around the product.

The present invention seeks to improve such known machines.

One aspect of the invention provides a machine for automatically forming, filling, and closing bags made from a flexible film provided with complementary closure ribs, the machine including means suitable for generating at least one fold associated with the film that is to constitute a bag, to form at least one gusset in the final bag, means suitable for conveying transversely a U-shaped strip integrally molded with the support strips for the closure ribs, means suitable for fixing said U-shaped strip and the associated support strips to the film, and means suitable subsequently for making a line of cut between the U-shaped Melbourne\003942072 Printed 14 November 2001 (11:46) strip and the strips supporting the ribs.

In various implementations, the above-mentioned fold can be longitudinal, i.e. parallel to the travel direction of the film, or it can be transverse, i.e. perpendicular to said film travel direction.

According to an advantageous characteristic of the invention, the machine further includes fixing means suitable, prior .to the bags being formed, for defining localized zones for securing one of the above-mentioned folds in locations that preferably correspond to transverse lines of sealing.

In a first embodiment, at least one longitudinal transverse fold is provided to form a gusset in the bottom of the bag, in which case the fold is formed in a region remote from the mouth that receives the closure assembly.

In a second embodiment, two longitudinal transverse •ego folds are provided, to form lateral gussets in the bag, extending transversely relative to the closure ribs.

In a first variant embodiment of the invention, the 20 longitudinal transverse fold is made in the form of a Zshaped fold in the body of the film.

g In a second variant embodiment of the present invention, the longitudinal or transverse fold is made by adding a folded strip to the film, e.g. corresponding to the desired 25 bottom gusset.

Another aspect of the invention provides a method of manufacturing bags from a flexible film provided with complementary closure ribs, by using an automatic forming, filling, and closure machine, the method including the steps of generating at least one fold associated with the film that is to constitute a bag, so as to form at least one gusset in the final bag, conveying a U-shaped strip transversely, which strip is integrally formed with support strips for the closure ribs, fixing said U-shaped strip and the associated support strips to the film, and subsequently forming a line of cut between the U-shaped strip and the strips supporting the ribs.

Melboume\003942072 Printed 14 November 2001 (11:46) According to another advantageous characteristic of the invention, the method further includes the step which consists, prior to the bags being formed, in defining localized zones for securing the above-mentioned fold in locations that preferably correspond to the transverse lines of sealing.

In a first variant of the method of the invention, the fold-generating step consists in forming a Z-shaped fold in the body of the film.

In a second variant of the method of the present invention, the fold-generating step consists in making the fold by adding a longitudinally-folded strip to a film, e.g.

0. corresponding to the looked-for bottom gusset.

oo *oo o o Melboume\003942072 Printed 14 November 2001 (11:46) Other characteristics, objects, and advantages of the present invention appear on reading the following detailed description with reference to the accompanying drawings given as non-limiting examples, and in which: Figure 1 is a diagrammatic perspective and crosssection view of a bag of the present invention, made using a film that is simple; Figure 2 is a diagrammatic perspective and crosssection view of a bag constituting another variant embodiment of the present invention made using a film that is composite; Figures 3, 4, 5, and 6 are cross-section views of bags constituting other variants of the invention, with Figures 3bis and 4bis showing implementation details of oooo 15 longitudinal lines of sealing; SFigure 7 is a diagrammatic perspective and crosssection view of a bag constituting another variant embodiment of the present invention, obtained using a closure assembly including a U-shaped support strip; 20 Figure 8 is a detail view of the closure assembly, and Figures 8bis and 8ter show two variants of said closure assembly; Figure 9 is a diagrammatic side view of an automatic forming, filling, and closing machine of the present invention; Figure 10 is a plan view of the machine; Figure 11 is a plan view showing a detail of means for localized heat sealing of a longitudinal fold, in application of the present invention; Figure 12 is a diagrammatic vertical section view of baffle-forming means used for making a longitudinal fold in the context of the present invention; SFigure 13 is a diagrammatic vertical section view of a longitudinal fold in accordance with the invention; Figure 14 is a diagram showing the risk of slip along the longitudinal fold, which risk is remedied by means of the present invention; SFigure 15 is a diagrammatic horizontal section view of the means for stretching in accordance with the present invention, prior to making the transverse lines of sealing; Figures 16 and 17 are horizontal section views through the filling chute of a machine of the present invention and they show the way in which it is possible to make bags having gussets of different depths on the same filler chute; Figures 18 and 19 are diagrammatic cross-section views of two variant embodiments of bags of the present invention having gussets of different depths, and made by adding a folded strip to a film; Figure 20 is a diagrammatic perspective view of a 15 variant machine of the present invention that operates by adding a folded strip to make the gusset; Figure 21 is a detail view at a transverse line of sealing; SFigure 22 is a diagrammatic side view of a filler 20 chute in accordance with the present invention; Figures 23, 24, and 25 are three horizontal section views through the same filler chute on planes XXIII-XXIII, XXIV-XXIV, and XXV-XXV of Figure 22; "Figures 26 and 27 show two variant embodiments of bags having pairs of gussets; and Figures 28 and 29 show two variants of ribs and strips disposed transversely on a film to form bottom gussets in the bags.

In the description below, the embodiments initially described all make use of bags including bottom gussets, thereby simplifying description. However, as mentioned above, the invention is not limited to gussets in that position. In particular, in a variant, the invention can apply to making bags having pairs of lateral gussets.

Also, the description begins with variant implementations in which the fold made in the film is a longitudinal fold, i.e. parallel to the film travel direction. Thereafter, other variants are described in which the fold is made transversely relative to the film.

In the accompanying figures, there can be seen a bag formed from a film 12. The film is preferably thermoplastic. However, the invention can be extended to any flexible film capable of constituting a bag. The bag includes a closure assembly 20 formed by two complementary closure ribs 22 and 24, respectively a male rib and a female rib that are fixed on the inside surface of the bag 10, at the mouth 11 thereof. The ribs 22 and 24 extend longitudinally in the first embodiments, along the film 12 that is being processed to manufacture a bag.

The bag is closed transversely perpendicularly to the ribs 22 and 24) by lines of heat sealing e o 15 In the first embodiments of the present invention, the bag 10 is provided with a gusset 40 in its bottom remote from its mouth 11ii.

In the figures, the gusset 40 is made up of two facets 42 and 44 which together form a tuck inside the 20 bag, having a concave face looking towards the outside.

Numerous configurations are possible for the ribs 22 and 24. By way of example, they may be integrally molded with the film 12, or they may be added thereto. For this S.purpose, the ribs 22 and 24 may be carried by respective strips 23 and 25 as shown in particular in Figures 3 and

S.

4, or they may be carried by a single strip 28 that is folded into a U-shape, as shown in particular in Figure i.

Such strips 23, 25, 28 may be fixed to the inside surface of the film 12 (or to the outside surface for the strip 28) by any appropriate means, preferably by heat sealing.

As can be seen in particular in Figure i, the closure assembly 20 may be provided in conventional manner with a longitudinal rip-cord 26 to facilitate opening the bag.

The bag 10 may be closed longitudinally by the strip 28 carrying the ribs 22 and 24 as shown in Figure 1, or by a longitudinal line of sealing 14, as shown in Figures 3 and 4, for example.

The longitudinal line of sealing 14 may be formed in various different locations on the bag 10, e.g. along the width of its side walls 15, 16 in the body of the bag as shown in Figures 3 and 4, or in the zone where a side wall 16 joins the bottom gusset 40, as shown in Figures and 6.

The overlap of the two margins of the film 12 at the longitudinal line of sealing 14 can be right-handed or left-handed, as contrasted by Figures 3, 4 compared with Figures 3bis, 4bis.

oooo 15 The film 12 may be a simple single-layer flexible Sfilm as shown in Figure 1, or it may be a composite film Smade up of a plurality of adjacent layers, e.g. by S. coextrusion, as shown in Figure 2.

In a preferred embodiment shown in Figure 7, the 20 U-shaped strip 28 supporting the ribs 22 and 24 is heatsealed halfway across its width to the margins 18 and 19 of the film 12. There are thus formed both an outer, first sheet 29 constituted by the web of the U-shaped strip 28 and an inner, second sheet 30 passing via the ribs 22 and 24. This prevents pressure inside the bag stressing the ribs 22 and 24 on opening, because the rib support is not connected to the margins 18 and 19 of the film 20 level with the ribs 22, 24, but at a point that is offset therefrom. This effect can be reinforced and even guaranteed by ensuring that the inner, second sheet carrying the ribs 22 and 24 is of longer dimensions than the outer sheet 29, as shown in Figure 7.

Figures 7 and 8 show a variant in which the U-shaped strip 28 is fixed to the inside surface of the margins 18 and 19 of the film 12. In a variant, as shown in Figure 8bis, the U-shaped strip 28 can be fixed to the outside surface of said margins 18 and 19 of the film 12.

Also, as shown in Figures 7, 8, and 8bis, the U-shaped strip 28 is fixed to the margins 18 and 19 of the film 12 via zones of the strip 28 lying between the ribs 22, 24 and the center of the strip 28 which may be provided with a rip-cord 26, for example. However, in a variant, as shown in Figure 8ter, the U-shaped strip 28 can be fixed to the margins 18 and 19 of the film 12 via zones of the strip 28 situated between the ribs 22, 24 and the longitudinal free edges of the U-shaped strip 28.

More precisely, in Figure 8ter, the strip 28 is fixed via its own longitudinal margins to the outside surface of the margins 18 and 19 of the film 12.

Nevertheless, in another variant, the strip 28 could be fixed via its own longitudinal margins to the inside ooeo 15 surfaces of the margins 18 and 19 of the film 12.

Under such circumstances, the looped closure assembly formed in this way can be sealed vertically to a margin of the film 12, like a fold.

Figures 9 and 10 show the general structure of a 20 machine 100 in accordance with the present invention.

These figures show a pay-out portion 102 followed by a drive portion 104 that includes a jumper roller 106 whose height varies. The gusset 40 is prepared in this portion 104 by means of a baffle 110 constituted by two overlapping and superposed plates 112 and 114. The

S..

baffle 110 defines a Z-shaped fold P, as can be seen in Figure 12.

Also, as mentioned above, according to the present invention, the machine 100 includes fixing means 118 suitable, prior to the bags being formed, for defining localized zones 13 for securing the above-mentioned fold at locations corresponding to the transverse lines of sealing (made subsequently).

These fixing means 118 are preferably provided at the portion 104 or at the portion of the machine 100 that is situated immediately downstream therefrom.

They can be implemented in various ways. In a preferred embodiment, they are designed to heat-seal spots-in the fold P in order to hold it together.

However, in other variants, the means may be designed to fix the fold by static discharge, by spots of adhesive, or by any other equivalent fixing means.

The above-mentioned fixing means 118 are preferably adjustable along the length of the film 12 so as to make it possible to adjust accurately the positioning of the fixing means relative to thezones that subsequently correspond to the transverse lines of sealing.

Naturally, it is also necessary to synchronize with care the instants at which the fixing means 118 are caused to operate relative to travel of the film 12, since the instants at which the fixing means 118 operate determine both the locations of the zones 13, and the pitch of said zones.

As mentioned above, securing the fold P in localized manner immediately after it has been formed enables the 20 fold to be held together all along its travel path. This thus constitutes an essential characteristic of the present invention. It should also be observed that since *:the fold is secured at locations corresponding to the transverse lines of sealing, the zones 13 do not interfere in any way with subsequent making of the bag.

Also, localized securing of the fold P facilitates subsequent making of the transverse lines of sealing, given the extra'thickness at such locations that results from the fold that is to form the gusset.

The film 12 provided with the fold P is then conveyed in conventional manner to the FFS machine proper which comprises a former 120, a filling chute 130, longitudinal heat-sealing means 135, and transverse heatsealing means 140.

More precisely, in the context of the present invention, the fixing means 118 serve to secure two of the walls of the fold P together when the film 12 is composite, and three portions thereof when the film 12 is simple.

The fold P formed on leaving the pay-out means 102 of the machine is thus subsequently held together as the film travels. For a composite film, only two portions of the fold P are generally fixed together so there is a risk of the fold P slipping laterally, as shown in Figure 14. To remedy this difficulty, it is preferable in the context of the present invention to provide a system for guiding the walls of the film 12 by wheels having axles movable under control and/or any other system for guiding the edges of the film.

The final fold P is preferably formed while the film 12 is being taken off, firstly adjacent to the ribs 22 e oe and 24, and secondly adjacent to the fold P, by means of a set of pneumatic, hydraulic, electromagnetic, or mechanical clamps 150 which pinch and stretch the film 12 while transverse heat-sealing is taking place.

Such clamps 150 are consequently controlled 20 sequentially to open and close firstly to take hold of the film and secondly to move laterally in order to apply a certain amount of tension to the film and avoid any *unwanted folding.

Such a clamp system is shown diagrammatically in Figure The fold P can be positioned on one side or the other of the axis of the tube 130 relative to its longitudinal line of sealing 14.

It should be observed that the present invention makes it possible to use a single filler tube 130 and a single former 120, which are expensive parts of an FFS machine, in association with different depths of fold P, and thus of gusset 40, merely by altering the area of overlap between the plates 112 and 114 constituting the shaping baffle 110.

Thus, Figures 3 to 6, 16, and 17 show gussets of various depths.

In another variant, the fold P can be finalized by being forced into the filler tube 130. For this purpose, it suffices to split the former longitudinally to form an inlet window 132 for the fold P and situated at an appropriate height (see Figure 22).

Such a window 132 and the corresponding shaping technique are shown in particular in Figures 22 to In the above embodiments, the gusset 40 is formed by making a Z-shaped fold in the film 12.

However, in a variant shown in Figures 2 and 18 to 21, the gusset 40 can be implemented by adding a strip of film in the vicinity of the former 120. This strip is fixed to the film 12 by any conventional technique, and preferably by heat-sealing.

o 15 This technique makes it possible to add a strip oooo **of composite or simple film to a composite or simple film fitted with a closure assembly 20 before it passes through the former 120, and the strip then forms the bottom gusset 40 by means of longitudinal heat-sealing.

20 It should also be observed that the transverse line of sealing 30 may be straight or curved to help make a bag freestanding in a vertical position after the gusset -40 has become deployed. More precisely, under such circumstances, the transverse lines of sealing 30 made on the two sides of the bag are symmetrical. To implement such curved transverse lines of sealing 30, it suffices to shape the transverse heat-sealing jaws 140 accordingly.

The strip 50 that is to form the gusset 40 can be prefolded or it can be folded in the machine. It is likewise pre-fixed in steps at zones 13 corresponding to the transverse lines of sealing 30, as mentioned above.

Here again, the size of the final gusset 40 depends on the width of the strip 50 used.

Naturally, the present invention is not limited to the embodiments described above, but extends to any variant coming within the spirit of the invention.

In particular, it will be observed that the film 12 can be provided with the closure assembly 20 before the fold P is made (with the closure assembly 20 being formed originally in the film 12 or being added thereto) or the closure assembly can be fitted to the film immediately upstream from the former 120.

Also, and in conventional manner, the advance of the film 20 can be driven and synchronized as a function of the operation of the heat-sealing jaws 135, 140, or it can advance continuously.

In yet another variant, it should be observed that with an add-on bottom gusset 40, the color of the gusset can be different from that of the body of the bag.

Also, in the context of the present invention, the o 15 transverse lines of sealing 30 may be made either to bond together the two walls 42 and 44 of the bottom gusset at the transverse lines of sealing, or else to avoid bonding them together in this way.

By way of example, accompanying Figure 26 shows an 20 embodiment in which the bag 10 has two longitudinal gussets 40a and 40b that are parallel to the closure ribs More precisely, in Figure 26, the two gussets and 40b are equidistant from the closure assembly Nevertheless, such equal distances are not absolutely necessary.

To make the two gussets 40a and 40b, it suffices to make two folds P in the film 12 prior to conveying it to the former 130, or to apply two strips 50 for this purpose, in which case the bag is made not from a single film 12, but from two overlying sheets 12a and 12b.

Figure 27 shows a a variant embodiment of a bag that has two lateral gussets 40a and 40b extending perpendicularly to the closure assembly 20. These lateral gussets 40a and 40b are likewise obtained by means of longitudinal folds formed in the film before it reaches the former, or by adding appropriate strips 50 to the film, as described above. In this case, means are provided to place the closure assembly 20 on the film 12 transversely to the travel direction of the film. Such means for conveying the closure assembly 20 in a transverse direction can be in compliance, for example, with the means described in the following documents: US-A-4 617 683, US-A-4 655 862, US-A-4 666 536, US-A-4 701 361, US-A-4 709 398, US-A-4 878 987, US-A-4 844 759, US-A-4 929 225, US-A-4 909 017; and 111 643. In Figure 27, reference 14 designates the longitudinal line of sealing between the free edges of the film 12, while references 30 and 32 designate the transverse lines of sealing that finish off the bags. It will be observed that the closure assembly 20 is advantageously adjacent to one of the transverse lines of So 15 sealing 32 to guarantee that the bags are leakproof in spite of the presence of the lateral gussets 40a and Where appropriate, it is possible to envisage making the fold(s) 40 upstream or downstream from the former.

In other variant embodiments, the fold 40 that is to 20 form the gusset can be a transverse fold, i.e. a fold extending perpendicularly to the travel direction of the film 12.

Under such circumstances, it is also possible to provide for the fold 40 being implemented in the form of a Z-shaped fold extending transversely in the body of the film 12.

However, it is preferable for a transverse fold to be made by means of a strip 50 that is itself folded longitudinally into a U-shape and that is added to the film 12.

Figure 28 shows such a U-shaped strip 50 with its convex side directed rearwards relative to the travel direction of the film 12, which strip is initially connected (integrally formed with) the support strips 23, 25 of the ribs 22, 24. The strip 50 connected to the ribs 22, 24 and placed on the film 12 is of a length equal to half the width of the film 12. One side of the U-shaped strip plus the adjacent support strip 23 is heat-sealed to the film 12 in a station upstream from the former 120. The other side of the U-shaped strip plus the second support strip 25 is heat-sealed to the inside wall of the film 12 constituting the package after the film has been folded into the tubular configuration and the package has been filled, i.e. while the package is being finished, in a station for performing transverse heat-sealing 140.

Such a strip 50 connected to the ribs 22, 24 may be conveyed transversely relative to the film 12 by means known for this purpose and as described in the abovementioned documents.

Naturally, it is necessary to provide the transverse 0000 heat-sealing station 140 with means suitable for cutting said strip so as to separate the U-shaped strip 50 proper 60.6that is to form a gusset from the ribs 22 and 24 along a line of cut referenced 200 in Figure 28. Thus, after cutting along the line 200, the ribs 22 and 24 are .0 20 connected to the mouth zone of a bag that has just been individualized, while the U-shaped strip 50 forms a gusset for the bottom of the bag that is being made.

The opposite configuration is also possible, i.e.

the assembly constituting the U-shaped strip 50 and the ribs 22 and 24 can be put into place with the convex side @0 of the U-shape strip at the front relative to the travel 0000 direction.

In another variant shown diagrammatically in Figure 29, such a U-shaped transverse strip 50 placed on the film 12 can be separated ad initio from the transverse closure ribs 22 and 24. This avoids the subsequent operation of cutting said strip as described with reference to Figure 28. Nevertheless, it is still necessary to separate bags in conventional manner along the line 202 between the closure ribs 22 and 24 and the strip 14 When using a transverse U-shaped strip 50, the operation of transversely heat-sealing said strip 50 to the film 12 can be adapted either to fix together the ends of the strip via the inside surfaces of the folds, in a manner comparable to Figure 27, or else to allow the inside surfaces of the fold to remain free, in a manner comparable to Figure 26.

In addition, in the context of implementing a transverse fold, it is possible in a manner comparable to implementing a longitudinal fold, to form a single fold that preferably forms the bottom gusset of a bag or multiple folds that form lateral gussets, in association e oo with closure ribs that can either be parallel or else ~perpendicular to the fold or folds.

go o* c

Claims (34)

1. 2. A machine according to claim i, wherein the fold is longitudinal, parallel to the travel direction of the film. i
2. 3. A machine according to claim 1, wherein the fold is 20 transverse, perpendicular to the travel direction of the film.
3. 4. A machine according to any one of claims 1 to 3, and further including means suitable for conveying closure ribs 25 longitudinally, parallel to the travel direction of the film. A machine according to any one of claims 1 to 3, and further including means for conveying closure ribs transversely, perpendicularly to the travel direction of the film.
4. 6. A machine according to any one of claims 1 to 5, and further including fixing means suitable for defining localized zones for securing the above-mentioned fold (P)
5. 7. A machine according to claim 6, wherein the fixing means defining localized zones for securing the fold are Melboume\003942072 Printed 14 November 2001 (11:46) 16 adapted to make said zones, prior to the bags being made, and in locations that correspond to the transverse lines of sealing.
6. 8. A machine according to any one of claims 1 to 7, wherein it is adapted to make at least one gusset parallel to the closure assembly.
7. 9. A machine according to any one of claims 1 to 7, wherein it is adapted to make at least one gusset perpendicular to the closure assembly. A machine according to any one of claims 1 to 9, wherein it is adapted to make at least two parallel gussets in the 15 bag. oo o oooo
8. 11. A machine according to any one of claims 1 to wherein the fold is made in the form of a Z-shaped fold in the body of the film. 0:
9. 12. A machine according to any one of claims 1 to wherein the fold is made by adding to a film, a strip that is folded in a U-shape and corresponds to the looked-for gusset. 0 13. A machine according to any one of claims 1 to 12, for forming bags based on film, in particular film made of thermoplastic material, the bags including closure ribs, the machine comprising a former that is fed with the film in the plane state coming from pay-out means, and delivering the film shaped into a tube; a filling chute which opens out into the former and consequently into said tube; longitudinal heat-sealing means for closing the tube longitudinally; and means suitable for generating sequentially a first transverse line of heat-sealing before a product is put into the tube via the filler chute, and then a second transverse line of heat-sealing when the product has been put into the tube, Melbourne\003942072 Printed 14 November 2001 (11:46) 17 thereby closing a package around the product.
10. 14. A machine according to any one of claims 1 to 13, wherein the fold is made before the film is brought to a former. A machine according to any one of claims 1 to 13, wherein the fold is made after the film has been brought to a former.
11. 16. A machine according to any one of claims 1 to wherein the gusset is made up of two facets which form a tuck inside the bag, having a concave face looking outwards. oo 15 17. A machine according to any one of claims 1 to 16, :o:wherein the film is prefitted with closure ribs before oooreaching a former. *ooo t o
12. 18. A machine according to any one of claims 1 to 17, 20 wherein the ribs are added to the film.
13. 19. A machine according to any one of claims 1 to 17 and 19, and further including means suitable for fixing the ribs to the film. *to t¢o A machine according to claims 18 or 19, wherein the ribs are carried by respective strips fixed to the inside surface of the film.
14. 21. A machine according to claims 18 or 19, wherein the ribs are carried by a single strip that is folded into a U-shape and fixed to the inside surface of the film.
15. 22. A machine according to claim 21, wherein the U-shaped strip carrying the ribs is heat-sealed to the free margins of the film in zones situated between the ribs and the center of the stip such that the pressure inside the bag does not Melbourne\003942072 Printed 14 November 2001 (11:46) stress the ribs on opening.
16. 23. A machine according to claims 21 or 22, wherein the U- shaped strip carrying the ribs is heat-sealed across its width to the margins of the film to form an outer first sheet including the web of the U-shaped strip, and an inner second sheet including the ribs, the inner, second sheet being longer in dimension than the outer sheet so that the presser inside the bag does not stress the ribs on opening.
17. 24. A machine according to any one of claims 1 to 23, wherein the film is a simple single-layer flexible film or a composite film made up of a plurality of adjacent layers, e.g. by coextrusion. A machine according to any one of claims 1 to 24, and o further including a baffle formed by two overlapping superposed plates for forming the fold which is Z-shaped. 20 26. A machine according to claim 25, and further including means suitable for modifying the overlap of the plates. oooe o*o
18. 27. A machine according to any one of claims 1 to 26, o*ooo wherein the fixing means are designed to fix the fold by 25 heat-sealing, by static discharge, or by spots of adhesive.
19. 28. A machine according to any one of claims 1 to 27, wherein the fixing means are adjustable along the length of the film.
20. 29. A machine according to any one of claims 1 to 28, and further including a system for guiding the walls of the film, which system includes wheels having axles movable under control or some other system for guiding the edges of the film. A machine according to any one of claims 1 to 29, and Melboume\003942072 Printed 14 November 2001 (11:46) 19 further including a set of pneumatic, hydraulic, electromagnetic, or mechanical clamps that pinch and stretch the film while transverse heat-sealing is taking place.
21. 31. A machine according to any one of claims 1 to wherein the fold is finalized by being forced into the filler chute.
22. 32. A machine according to claim 31, wherein the former and the filler chute include a window for receiving the fold
23. 33. A machine according to any one of claims 1 to 32, wherein the transverse lines of sealing are curved to make the bag more suitable for freestanding in a vertical position 15 after the gusset has been deployed. oooo
24. 34. A machine according to any one of claims 1 to 33, o wherein the add-on gusset is of a color that is different from that of the body of the bag.
25. 35. A machine according to any one of claims 1 to 34, wherein it is adapted to fix the ends of the fold via the inside surfaces thereof.
26. 36. A machine according to any one of claims 1 to 34, •wherein it is adapted to leave the ends of the fold free at the inside surfaces thereof.
27. 37. A machine according to any one of claims 1 to 36, and further including means suitable for conveying a U-shaped strip transversely and for fixing said strip to the film.
28. 38. A machine according to claim 37, wherein a first branch of the U-shaped strip is fixed to the film before it is put in the form of a tube, while the second branch of said strip is fixed to the film during the bag-finishing step. Melbourne\003942072 Printed 14 November 2001 (11:46)
29. 39. A machine according to any one of claims 37 to 38, wherein the U-shaped strip is of a length equal to half the width of the film.
30. 40. A method of manufacturing bags from a flexible film provided with complementary closure ribs, by using an automatic forming, filling, and closure machine, the method including the steps of generating at least one fold (P) associated with the film that is to constitute a bag, so as to form at least one gusset in the final bag, conveying a U- shaped strip transversely, which strip is integrally formed with support strips for the closure ribs, fixing said U- shaped strip and the associated support strips to the film, and subsequently forming a line of cut between the U-shaped 15 strip and the strips supporting the ribs. *fee :41. A method according to claim 40, and further includes the step of defining localized zones securing the above-mentioned fold. :42. A method according to claim 41, wherein the locations at which the fold if secured correspond to the locations of subsequent transverse lines of sealing. o*oo 25 43. A method according to any one of claims 40 to 42, S• wherein that the step of generating the fold consists in forming a Z-shaped fold in the body of the film.
31. 44. A method according to any one of claims 40 to 42, wherein the step of generating the fold consists in making the fold by adding to a film a longitudinally-folded strip corresponding to the looked-for gusset. A method according to any one of claims 40 to 44, wherein it further includes a step consisting in conveying lengths of closure rib onto the film transversely to the travel direction thereof. Melboume\003942072 Printed 14 November 2001 (11:46)
32. 46. A method according to any one of claims 40 to wherein a first branch of the U-shaped strip is fixed to the film before it is put into tubular form, while the second branch of said strip is fixed to the film during the bag- finishing step.
33. 47. A machine substantially as hereinbefore described with reference to the accompanying drawings.
34. 48. A method substantially as hereinbefore described with reference to the accompanying drawings. Dated: 14 November, 2001 15 FREEHILLS CARTER SMITH BEADLE Patent Attorneys for the Applicant .:FLEXICO-FRANCE S *o S Melbourne\003942072 Printed 14 November 2001 (11:46)