WO1997045339A1

WO1997045339A1 - Method for manufacturing a container receiving bulk products and container thus produced

Info

Publication number: WO1997045339A1
Application number: PCT/FR1997/000946
Authority: WO
Inventors: Didier Ayroulet
Original assignee: Filtisac France
Priority date: 1996-05-30
Filing date: 1997-05-30
Publication date: 1997-12-04
Also published as: FR2749283B1; FR2749283A1; EP0857151A1

Abstract

The invention discloses a method for manufacturing a container, in particular a large volume container for receiving bulk products, and containers thus produced. The tubular or prismatic container comprises an internal lining (4) and an external bag, one of the two bases thereof constituting the bottom and the other the top of the container. The top comprises or constitutes at least one loop forming a lifting handle (33) enabling gripping, filling and handling. At least part of the lateral surfaces and bases of the lining (4) are covered with at least one contiguous coil winding (13, 24, 29) of a flexible strip (8) or band, integrally overlapped to ensure container solidity. The invention is useful for the packaging of various bulk industrial products such as chemical, building and agri-food products.

Description

METHOD FOR MANUFACTURING A CONTAINER FOR RECEIVING BULK PRODUCTS, AND CONTAINER THEREFOR

GOT.

The present invention relates to containers intended to receive bulk products, and more particularly to large capacity containers.

The present invention has two objects linked together by the same inventive concept: firstly a process which is expressed in several variants for the preparation of such containers and then the various containers obtained by the implementation of the variants of the inventive process. Any container corresponding to the aforementioned types currently comprises an inner lining or bag made of a flexible film, generally made of polyethylene or more exceptionally of polypropylene, a lining which is intended to seal the container. It also includes an outer bag intended to ensure the mechanical strength of the container and obtained by assembling woven parts from ribbons or narrow strips.

Each container has a general shape developing in a longitudinal direction or height, and more precisely a cylindrical or prismatic shape, one of the two bases constituting the bottom and the other the top of the container. To allow gripping, filling and handling of the finished container, its extreme upper part comprises or constitutes a loop or the like, intended to serve as a gripping handle.

In general, although flexible, the material constituting the outer bag of the container is always chosen to be very resistant because the container is intended to receive several hundred kilos of any bulk product from building industries, food industry

CUϋ • • •

As already indicated, the outer bag of each of the aforementioned types of containers is obtained by assembling woven parts, panels, panels, for example by sewing. These parts are obtained from narrow strips of width between 2 and 5 mm from a flexible material, preferably polypropylene, taking into account the resistance of this material. Weaving is carried out in the traditional way using the so-called "warp and weft" mode, in which narrow strips arranged in the warp direction intersect with narrow strips disposed in the warp direction.

The assembly of these parts is carried out so that the direction of the warp of the fabric used extends in the longitudinal direction or height of the container and that the direction of the weft of the fabric is perpendicular to this longitudinal direction.

The manufacture of such a bag includes the extrusion of a narrow strip of polypropylene, the weaving of this narrow strip, the cutting of the woven pieces and finally the assembly or making of the pieces thus cut according to the arrangement described above.

It is understood that each stage of the manufacture of this type of outer bag requires significant production time. The purpose of the present invention is to eliminate the weaving, cutting and assembly steps detailed above and to replace these three successive steps with a single continuous step.

The present invention therefore proposes to pass directly from the extrusion operation of the polypropylene strip to the production of the finished product with a strip of greater width which ensures an interesting gain in production time.

But this saving of time is not the only advantage of the present invention relative to the traditional weaving technique used prior to the invention.

The present invention eliminates the assembly operation by sewing, welding or gluing the cut pieces. This assembly alters the resistance of the bag at any junction line between two adjacent parts. This reduction in strength is evaluated at 30%, whatever the method of assembly used. To take account of this loss of resistance, any bag is manufactured so as to be oversized by the quality of the fabric and that of each of its seams in order to present a satisfactory and sufficient resistance to the use for which it is intended.

By eliminating the joining of parts, the implementation of the present invention makes it possible to obtain a significant gain in weight of the base material used, therefore in the cost of the finished product since it suffices that this material is 30% less by weight. to that used in the traditional technique by weaving "warp and weft" to achieve the same result. The present invention firstly relates to a process for manufacturing a flexible container, for example intended for receiving bulk products, of the type comprising an inner lining or bag made of a flexible film, generally made of polyethylene or polypropylene, intended for sealing, and an outer bag obtained by crossing strips of flexible material, generally polypropylene or polyethylene, intended to ensure the mechanical strength of the container, the container having a general shape in cylinder or prism whose l one of the two bases constitutes the bottom and the other the top of the container, which comprises or constitutes at least one loop for use as a lifting handle for gripping, filling and handling of the container, the method being characterized in that the lining is arranged around a shrink mold having the shape of the container to be produced, in that the all or part of the lateral faces and bases of the lining are covered by a first winding with contiguous turns of the strip of flexible material, by at least one rotation about an axis parallel or substantially parallel to the bases of the container to be produced, then that the side faces of the lining are covered by a second winding of the strip of flexible material by rotation about an axis perpendicular or substantially perpendicular to the bases of the container to be produced, so using this second winding to maintain sufficient cohesion at the level of the first winding, and in that, simultaneously with each of the two aforementioned recoveries, the first ba is secured ndelette wound to the lining, and respectively the second strip to the first, by gluing or by heat-sealing, and finally in that the mold is retracted to release and extract the finished container thus obtained.

In other words, by implementing the method according to the invention, the weaving of narrow strips used in the technique prior to the invention is replaced by a crossing of strips by simple superposition in which one proceeds by at least two successive crossed windings. of a wider strip. The strip of the upper layer is simply placed perpendicular to the strip of the lower layer and is glued to this strip of the lower layer.

Other specific advantages of the method according to the invention compared to the prior art can be stated as follows: a) in the case of weaving, each strip warp and even weft extends by obligation in a zigzag over its entire length; now, to each salient angle of this succession of zigzags corresponds a zone of weakening of the resistance of the strip; by implementing the invention, the use of the strip is optimized by applying it always perfectly flat or straight, either on the lining or on the strip of the lower layer; b) always in the case of weaving, but this time during its manufacture, it is inevitable to cause a compaction of the weft strip when placing the immediately following weft strip; this settlement, the importance of which results in a loss of covered surface area appreciated at around 20%, is eliminated by the implementation of the method according to the invention since the latter provides that the contiguous strip elements are all always perfectly dishes; c) according to the prior art, the lining is introduced into the bag after making it and it is then glued to the inside of all the walls of the bag in order to conform to the shape of the latter; now, thanks to the invention, this additional gluing operation is also eliminated, hence a new saving in the cost of manufacturing the bag, since the strip which, by winding, will form the bag is directly glued to the lining as it is wound up; d) the weaving, cutting, making and sewing operations which the implementation of the prior art requires have disappeared.

In its application to the manufacture of a container having the shape of a prism with a square or rectangular section, the method according to the invention provides that the phase of first winding with contiguous turns is obtained in two successive operations, one consisting in covering at least partly two of the opposite lateral faces of the lining and at least partly its bases, by rotation about an axis parallel or substantially parallel to the bases of the container to be produced, the other consisting in covering at least for part the other two opposite lateral faces of the lining and at least partly its bases, by rotation about an axis which is also parallel or substantially parallel to the bases of the container to be produced and which is itself perpendicular to the first axis.

In its application to the manufacture of a container having the shape of a prism with at least hexagonal section, the method according to the invention provides that the phase of first winding with contiguous turns is obtained in n successive operations, one consisting to cover at least partly two of the opposite lateral faces of the lining and at least partly its bases, by rotation about an axis parallel or substantially parallel to the bases of the container to be produced, the others each consisting of covering, two by two , always at least in part, the other opposite lateral faces of the lining and its bases, by rotation about an axis which is also parallel or substantially parallel to the bases of the container to be produced and which forms an angle of 180 / n relative to the axis of the previous rotation.

According to a first implementation variant, the method according to the invention is characterized in that the operation or each of the successive operations of first winding is carried out by rotation of the mold / lining assembly around a parallel axis at the bases of the container to be produced, and in that the second winding phase is carried out by rotation of the mold / lining assembly around an axis perpendicular to said bases, the strip dispenser remaining fixed in rotation during each of the above winding phases.

According to a second implementation variant, the method according to the invention is remarkable in that the operation or each of the successive operations of first winding is carried out by rotation of the strip dispenser around an axis parallel to the bases of the container to be produced, and in that the second winding phase is carried out by rotation of the strip dispenser about an axis perpendicular to the bases, the mold / lining assembly remaining fixed in rotation during each of the phases of above winding.

Advantageously, the method according to the invention can also provide that, during the phase of first winding with contiguous turns, that this phase is carried out in one, two or n operations, the handle or handles allowing gripping, filling are carried out simultaneously. and handling of the finished container. In other words, the implementation of the present invention makes it possible to produce, during the same operation, the bag and its loop (s) serving as lifting handle (s), which constitutes another important advantage relative to the traditional technique which that, on certain types of bag, after making them, it is necessary to attach to their top, by sewing, welding or gluing, one or more pieces each intended to constitute a lifting loop. In the aforementioned case, it can then also be provided that, during the second winding phase, said second winding extends beyond the lateral faces of the lining on the side of the handle (s) of the container, then gradually tightening, so as to ensure shaping of the said handle (s) by grouping the loops provided at their ends. According to a manufacturing method, during the first winding phase with contiguous turns carried out in one, two or n operations, all of the side faces and all of the bases of the lining are covered.

According to another manufacturing method, and always during the phase of the first winding with contiguous turns carried out in one, two or n operations, only part of the side faces and only part of the bases of the lining are covered, in that the 'there is in the area not covered with at least one of said bases a mold element intended for the production of a chute for the entry or exit of bulk products, then in that said chute is formed during the second winding phase, by covering the mold element which corresponds to it, by winding contiguous turns of the strip of flexible material around said mold element. The observation made previously with regard to the attachments intended to each constitute a lifting loop applies to the production of any chute; according to the traditional technique, any chute is obtained from an attached piece secured to the bag after making the latter. Thanks to the invention, any chute intended to be used for filling or emptying the bulk product can now be produced at the same time as the bag, thereby further saving time and thus appreciably reducing the manufacturing cost.

Advantageously, the method according to the invention can also provide that, during the second winding phase, the lateral faces of the lining are completely covered by a winding with turns which are also contiguous.

According to yet another variant of the abovementioned method, during the second winding phase, only partially covers the lateral faces of the lining, said second winding being made at least in places with non-contiguous turns but in an amount sufficient to maintain cohesion at the level of the first winding.

A second object of the present invention is, for example, a flexible container obtained by the implementation of any one of the modes of execution of the manufacturing method according to the invention described above. The container being the result of the process there is no need to describe it in detail.

It is of the type comprising an inner lining and an outer bag and has the general shape of a cylinder or of a prism of which one of the two bases constitutes the bottom and for the other the top of the container which comprises or constitutes a handle for gripping, filling and handling the container.

Such a container is characterized in that at least a portion of the lateral faces and of the bases of its lining are covered with at least one winding with contiguous turns of a strip of flexible material, this or these windings ensuring the resistance mechanical of said container. According to a first embodiment, the bottom of such a container is covered at least in part with at least one winding with contiguous turns of a strip of flexible material.

According to a second embodiment, its bottom is entirely covered with at least one winding with contiguous turns of a strip of flexible material. In this alternative embodiment, the lateral faces of the container are entirely covered with a first winding with contiguous turns of a strip of flexible material and at least in part of a second winding of a strip of flexible material which crosses perpendicularly the first winding. Still in this particular case, the second winding of the container can be a winding with non-contiguous turns capable of maintaining sufficient cohesion at the level of the first winding. In another construction variant, the lateral faces of the container can be entirely covered with two windings with contiguous turns of a strip of flexible material which extend in two substantially perpendicular directions. In the latter case, the or each of the lifting handles formed at the top of the container is either obtained by a single winding with contiguous turns of a strip of flexible material, or obtained by two windings with contiguous turns of a strip of flexible material , the general directions of said two windings being substantially perpendicular to each other.

Finally, in the particular case where it must include at least one chute, for the entry or exit of bulk products, it can advantageously be provided that said chute is also covered with at least one winding with contiguous turns of a flexible material strip.

An obvious additional advantage of the invention makes it possible to envisage making all the desired container shapes. It suffices to provide for manufacturing support a retractable mold of a shape suitable for the embodiment that one wants to obtain. In addition, in all cases, it is possible to obtain, during the same manufacturing operation, all the constituent elements of the container, that is to say the outer bag itself, but also, if necessary, its lifting handle (s) as well as its chute (s), respectively for entering and discharging the divided product that said container is intended to receive.

We will understand the invention by reading of the additional description which follows of several preferred embodiments of the invention, and with reference to the accompanying drawings in which:. FIG. 1 schematically represents, in perspective, a retractable mold around which the flexible container according to the invention will be manufactured,. FIG. 2 represents, still schematically, the installation around the retractable mold of FIG. 1 of a lining or bag, inside the future container, and intended to ensure the sealing of the latter,. FIG. 3 schematically illustrates, according to a first mode, the first operation of the phase of first winding with contiguous turns of the mold / lining assembly mounted in accordance with FIG. 2,

. FIG. 4 illustrates the phase of second winding of the intermediate product obtained in accordance with FIG. 8, at the end of the phase of first winding with contiguous turns,. FIG. 5 schematically illustrates, according to a second mode, the first operation of the phase of first winding with contiguous turns of the mold / lining assembly mounted in accordance with FIG. 2,. FIG. 6 illustrates the phase of second winding of the intermediate product obtained in accordance with FIG. 5, at the end of the phase of first winding with contiguous turns,. FIG. 7 schematically represents the successive phases of the manufacture of a container according to the invention provided in the upper part with a lifting handle produced directly during the abovementioned manufacture,. FIG. 8 illustrates the successive phases of the manufacture of a container similar to that obtained in accordance with FIG. 7, and being distinguished only in that the second winding extends beyond the lateral faces of the lining on the side of the handle of the container, while gradually tightening, so as to ensure better shaping of said handle by throttling it at its roots, Figure 9 illustrates the different phases of the manufacture of another variant of container provided at its upper part with four lifting handles and, at its lower part, with a chute allowing the evacuation of the divided product which said container will contain, FIG. 10 represents in bottom view and, respectively, in top view the container with four lifting handles obtained in accordance with FIG. 9, FIG. 11 schematically represents, in perspective, a mold / lining assembly intended for the manufacture of another variant of container of tubular shape, FIGS. 12 and 13 schematically represent the phases of first winding, and respectively of second winding, of the mold / lining assembly of FIG. 11, the tubular intermediate product obtained at the end of the first winding phase being folded back on itself in order to conduct the second winding phase, in order to constitute two small adjacent and adjoining containers, which, together, constitute a U whose middle part of the central core forms the lifting loop of the two small associated containers, FIG. 14 schematically represents the successive phases of the manufacture of a last variant of container, the features of which are that they are of smaller size and do not have a lifting handle, FIGS. 15 to 20 schematically illustrate the use of a retractable mold which can be expanded by inflating or filling, . FIGS. 21 and 22 illustrate the wide-band variant formed by several juxtaposed strips and its use by winding to form the container,. FIG. 23 is a schematic view illustrating a first particular winding on a retractable body serving as a mold,. Figure 24 is a schematic view explaining the formation of the preformed sheath by an assembly, a winding of suitable shape intended to come to cover with securing the first windings existing on the retractable mold.

Various variants of the manufacturing process according to the invention of a container have been shown in the accompanying drawings.

In all these manufacturing variants, a mold 1 is used for the core which has the general shape of the container to be produced without being limited to a container of the bag type. However to simplify the description, we will take for example a container of the bag type.

The bag type containers always have a generally tubular shape and more particularly in a cylinder or a prismatic shape, one of the bases constituting the bottom and the other the top of the container. The shape of the retractable mold 1 will therefore also be at least approximately that of a cylinder or a prism.

In the example shown in Figure 1, the mold 1 has the shape of a cube whose apex 2 is open so as to allow access to the devices provided inside this mold, for example jacks, which control the pivoting of certain parts of the walls of the cube, for example folding flaps, and by means of which the mold is retractable or the like.

As a variant, the mold 1 can be a envelope inflatable using a liquid or gaseous fluid under pressure or an envelope filled with a finely divided solid material.

Around the retractable mold 1, a lining or bag 4 is made from its bottom 3 consisting of a flexible film, generally made of polyethylene or more exceptionally of polypropylene, which also has the shape of the container to be produced.

This flexible lining 4 is conventionally intended to seal the bag.

Depending on its shape, the lining 4 can have on its bottom 5 one or more weld lines 6 connecting panels cut from the original film to form a flexible envelope of the receptacle type.

To allow the wrapping of the mold 1 by the lining 4 and more particularly to thread it onto the mold 1 as shown in FIG. 2 by the arrows 7, the volume defined by the lining is also open at the end.

In accordance with a first variant of the manufacturing process shown in FIGS. 3 and 4, the assembly formed by the mold 1 and the lining 4 is then covered by several windings of a strip 8 of flexible material, generally polypropylene or more exceptionally polyethylene. It is important that this material is mechanically resistant, that is to say adapted as to its thickness to the load of bulk product which it is intended to contain because the covering by winding strips according to the invention is only the constituent element in itself of the outer bag of the container.

The strip 8 used may advantageously be a strip of width between 5 and 15 mm, therefore significantly wider than that used in the traditional weaving technique which is only in the range of 2 to 5 mm.

Firstly, a first covering of the lateral faces 9, 10 and of the bases 11, 12 of the mold coated with the lining 4 is carried out by a first winding 13 with contiguous turns of the strip 8, by rotation of the mold with the lining 4 around an axis 14 parallel or substantially parallel to the bases 11, 12, according to the arrows 15.

So that this winding 13 takes place at contiguous turns, the coil 16 from which the strip 8 is unwound is subjected to a transverse translational movement 17 during the entire rotation of the mold around the axis 14, this- it also remains stationary in translation. At each rotation, the pitch of the movement 17 is equivalent to the width of the strip 8.

As a variant, throughout the rotation, the coil 16 can remain immobile in translation and it is the mold which is subjected to a transverse translational movement always at a step equal to the width of the strip 8.

The strip 8 is glued to the face which will come into contact with the lining 4, for example by means of a distributor-glue dispenser 18 which sprays an adhesive 19 of the so-called "hot melt" type or any other adhesive compatible with polypropylene.

The joining of the strip 8 wound with contiguous turns on the lining 4 can be obtained by heat sealing. This first winding 13 with contiguous turns is produced lengthwise, that is to say in the direction of the load of the container. It is hereinafter called the chain winding. An offset 20 is created for the winding 13 with contiguous turns in the upper part of the mold. This offset will then be used to form the container lifting handle (Figure 3). In the case where the container to be produced is flat or practically flat, the mold and the bag are of the pocket type. The first winding 13 described above, obtained by rotation about the axis 14, suffices to cover with contiguous turns the only two lateral faces 9, 10 of the mold and the bases 11, 12 which each reduce to an edge.

On the other hand, if the container to be produced is thick and if the mold 1 / lining 4 assembly consequently has at least two other lateral faces, respectively 21, 22, not covered by the first winding 13, a second operation is carried out. winding of the strip 8, also with contiguous turns, by rotation of the mold / lining assembly about an axis 23, shown in phantom in Figure 3 which is perpendicular to the first axis 14 of rotation.

By then applying the same means as those described above, there is thus obtained a second first winding 24 with contiguous turns of "chain", second first winding which is shown in FIG. 4 in solid lines opposite the side face 21 and in dotted lines 25 opposite the upper base 12 of the mold / lining assembly. In other words, at the end of these two rotations around the axes 14 and 23, two first windings 13, 24 are formed around the lining 4, with contiguous turns in the "chain" direction, that is to say in the direction of the load of the container, windings which ensure recovery of all of the side faces and of the bases of the lining.

If, instead of being of square or rectangular section, the container to be produced has the shape of a prism with at least hexagonal section, it is clear that the operations 13, 24 of first winding (s) will be multiplied ( s) identically to what has been described previously, by at least three rotations around axes which are all parallel or substantially parallel to the bases 11, 12 and which, between them, make an angle of 180 ° / n, n being the number of operations of first winding (s) in the direction " string "then necessary.

When the first winding in this warp direction obtained in one or more operations is completed, a second winding phase of the already covered lining is carried out, using the means shown in FIG. 4.

To do this, the mold / lining assembly is rotated around an axis 26 perpendicular to the first and, during this new rotation shown diagrammatically by the arrows 27, the lateral faces 9, 10, 21 and 22 of the lining 4 (already covered by the first windings 13, 24 with contiguous turns) by means of a complement of the same strip 8 or another strip delivered from the support 16 on which it is wound.

This second winding is then carried out in a direction perpendicular to the direction of the load of the container and will be called "weft" winding. This second winding is made with contiguous or non-contiguous turns, the quality of this second winding being such that it simply guarantees the maintenance of sufficient cohesion of the first winding in order to prevent this first winding from weakening in certain areas. In FIG. 4, the second winding has however been shown diagrammatically as also being carried out with contiguous turns, that is to say that at each rotation of the mold / lining assembly around the axis 26, the strip 8 shifts by a step equivalent to its width. For this, as has been seen previously, either the coil 16 is moved longitudinally, from top to bottom, as indicated by arrow 28, the assembly mold / lining being stationary longitudinally, or it is this assembly which is movable longitudinally, in a direction of movement then opposite to that marked by arrow 28 and it is then the coil 16 which is stationary longitudinally, produced as during driving of the operation or operations of first winding (s) 13, 24 with contiguous turns. The strip 8 or another intended to make the second winding 29 is also glued using the distributor-glue 18 so as to ensure the necessary and sufficient cohesion at the level of this first winding.

A container has thus been produced in which all the lateral faces and the two bases of the lining 4 are covered by at least one first winding with contiguous turns of a polypropylene strip in the warp direction and whose lateral faces are also covered by a second winding, with contiguous or non-contiguous turns, this second winding 29 having the equivalent of the weft direction.

The container thus produced can then be extracted from the installation core. For this, it is sufficient to retract for example by deflating the mold 1 and to release the container.

The container thus formed consists of an inner lining 4 which provides sealing and an outer bag formed from the windings 13, 24, 29 obtained by crossing strips which guarantee the mechanical strength of the container, the outer bag being glued when making on the inner lining 4.

In the particular case represented in FIGS. 3 and 4 in which, during the preparation of the container, provision has been made to simultaneously create at least one lifting handle, the parts of the strip of the first windings 13, 24 present at the offset 20 will be grouped and engaged in a holding part: loop, loop, ring or other, as indicated below.

According to a variant of the aforementioned manufacturing process, shown in FIGS. 5 and 6, the same container as that obtained above is produced by a simple inversion of the mobile and fixed parts of the means used. Thus the mold remains fixed while the dispenser-glueer 18 of the strip 8 is made mobile in rotation around the mold.

Thus, while the mold 1 / lining 4 assembly is fixed in rotation, the first winding operation with contiguous turns 13 is carried out by rotating the support 16 of the strip 8 around an axis 14 'coincident with the old axis 14, as shown by the arrows 30 in FIG. 5.

The glue dispenser 18 which sprays the glue 19 on the strip 8 has the same rotational movement as the coil 16 around the mold

1.

If the container to be produced is thick, as shown in FIG. 5, a second winding operation is carried out with contiguous turns of the strip 8, by rotation of the reel 16 and of the distributor-glue dispenser 18 around an axis 23 ', confused with the old axis 23.

To make the first windings 13, 24 with contiguous turns, the mold 1 / lining 4 assembly is driven by a rectilinear movement of movement, designated by the arrow 17 '.

When the operations of the first winding (s) with contiguous turns are completed, with the possibility of an offset 20 in the upper part, in order to subsequently form a lifting handle, the second phase is carried out in the same way. winding while keeping fixed in rotation the mold / lining assembly and by rotating the reel 16 and the dispenser-glue 18 around a vertical axis of rotation 26 ', coincident with the old axis 26. During this rotation around the axis

26 ', the direction of which is represented in FIG. 6 by the arrows 31, the first windings 13, 24 are covered with contiguous turns by the second winding 29, with turns also contiguous or not in a rectilinear movement from bottom to top, shown diagrammatically in Figure 6 by arrow 32.

A container identical to the previous one is thus obtained.

The successive phases of windings shown diagrammatically in FIGS. 3 and 4 have been shown in more detail in FIG. 7. In particular, the prediction of the offset 20 shows the formation of the parts of the first windings 13, 24 with contiguous turns in the "chain" direction of the load on the container thanks to which we achieve the simultaneous production of a handle 33 allowing the subsequent handling of the container. This handle 33 can also be formed as soon as the two operations of the first windings 13, 24 are completed, by rotation about the axis 14 and respectively of the axis 23. For this, all the elements of the strip 8 belonging at the two offsets 20 are grouped together at their extreme upper middle part and joined and then held together by gluing, by welding, or more simply using a strap, a ring or a polypropylene strip 34 or all another means which surrounds the grouping of the elements of strips and which is then sewn or glued on itself.

After the second winding 29 has been formed, shown in contiguous turns in FIG. 7, the finished container 35 is released and disengaged after having retracted the mold 1. If necessary, provision can also be made to add this container 35, already provided with a lifting handle 33, 34, to the upper part, of a chute 36 allowing said container to be loaded with bulk material. This chute 36 is easily placed in the upper part of the finished container, just below the lifting ring 34.

There has been shown in FIG. 8 the various phases of the manufacture of a container similar to that obtained in accordance with FIG. 7, and which differs from the latter only in that the second winding 29 shown with contiguous turns on this Figure 8 is continued beyond the side faces of the lining, that is to say beyond the base of the two offsets 20, with a gradual tightening of said second winding 29, so as to ensure a shaping of the lifting handle 33 by throttling it at its ends 37. The container 38 thus obtained has a better ordered lifting handle 33, while allowing the introduction of a chute 36 between the lifting ring 34 and the ends 37 of the lifting handle 33, a chute through which the container 38 will be filled with bulk products.

It was shown in Figures 9 and 10 the winding phases of another form of container which differs from the previous two in that it has four lifting handles, as well as an inlet chute and a chute output of the divided product obtained during the manufacture of such a container.

To do this, there is in the upper part 12 and, respectively, in the lower part 11 of the mold 1 / lining 4 assembly, an additional element, respectively 39 and 40, each corresponding in shape and in size to the chute to achieve. In this case, only part of the side faces 9, 10 of the lining is covered and only part of the bases 11, 12 of the lining, leaving areas 41 of the side faces and 42 of the bases located at right angles to the covering items 39 and 40.

Similarly, during the conduct of the second operation of the first winding phase 24, only part of the side faces 21, 22 of the lining and only part of the bases of said lining are covered, so that they are not covered in the warp direction, the zones 43 of the two other lateral faces 21, 22. For their part, the parts 42 of the bases 11, 12 of the lining which until then have not been covered are now in turn covered, as shown in FIG. reference 44.

In this construction, the second winding phase 29 is advantageously carried out with contiguous turns, so that the lateral faces 9, 10, 21, 22 of the container to be produced are completely covered, including in their areas 41, 43 hitherto not covered. .

During this second winding phase 29, the two mold elements 39 and 40 are covered with the aid of the strip 8, preferably with contiguous turns, so that the finished container comprises, at the time of manufacture, a chute d inlet 45 and an outlet chute 46. In addition, in the upper part of the container, in each of its angles, the strip elements obtained as above are brought together by means of the offsets 20 and a finished container 47 is thus obtained with four lifting handles 48.

FIGS. 11 to 13 show some of the stages in the manufacture of a container 52 of a particular shape according to which it is formed of two small containers 53 joined together.

To do this, a mold 1 and a tubular and very elongated lining 4 are used (FIG. 11). The two operations of the phase of first windings 13, 24 are carried out according to one of the two modes shown in Figures 3 and 5, without offset

20 because the lifting handle of the container 52 to be produced will be obtained differently.

Indeed, in this specific construction, the intermediate product 54 obtained at the end of the first winding phase 13, 24 is folded back on itself, through its middle, and the second winding phase 29 is carried out on the folded product. Two smaller containers 53 are thus obtained, joined together since joined by the strip distributed in contiguous turns during the second winding phase 29. It is made so that this second winding leaves free the upper part corresponding to the product folding zone intermediate 54, as designated by 49 in FIG. 13. It suffices to join together at the end all the strip loops at the level of the edge constituting the upper termination of the folding zone 49 to form a lifting handle 50 of the two containers 53 joined together, this meeting being materialized using any link, a strap, a ring or a polypropylene strip 34 sewn on itself.

Finally, it has been shown in Figure 14 the manufacture of a container 55 of smaller size, therefore not requiring a lifting handle. The first winding phase 13 with contiguous turns is then obtained in a single operation. At the end of the second winding phase 29, with contiguous turns or not, it suffices to split the container produced, as indicated by arrow 51, to allow it to be filled with bulk product. This container 55 can then be sealed by any traditional means at its split upper part. It will more particularly be intended to receive between twenty-five and fifty kilos of bulk products, while the containers 35, 38, 47, 52, obtained according to the other manufacturing methods described above, and all with at least one, or even four lifting handles, can receive between five hundred and two thousand five hundred kilos of bulk products. To save time in making the bag or the sachet, as illustrated by FIGS. 21 and 22, a wider strip or strip 56 which is uniform or formed by the juxtaposition-lateral junction of a plurality of elementary strips or strips, for example, will be used. three such as 57,58,59 such as for example those described above and referenced 8.

The juxtaposition-junction can come from conventional means: seams, bonding of the edges or by simultaneous extrusion or separate coextrusion and hot coplanar meeting.

The manufacturing process takes place in the same way as already described except that the bands 56 cannot exceed a certain width due to the formation of loops for the gripping handles which cannot exceed a certain width to give the necessary flexibility. to grip.

As already described above and illustrated by way of illustration in FIGS. 15 to 20, one of the variants of the method according to the present invention consists in using as a retractable mold 1 a flexible mold which is expandable, swellable or expandable by a liquid or gaseous fluid under pressure or even expanded by filling with a divided solid material compacted or made denser or even by the use of a material for the mold or a filling material capable of expansion or hardening. One example of the shape of a container produced using an expandable mold will be that of a flat pocket-type body for closed flat or cylindrical containers of identical or similar shape to that of the container itself. This expandable mold is made of extensible or expandable material suitable for affecting the final shape desired when inflated or filled to a pressure or density sufficient to give it the desired strength and rigidity.

Upon observation of the figures from 15 to 20, the inflation and then the extraction after deflation of the mold in the retracted state are observed through the space situated between the loops of the handles. This extraction can also be carried out in the space delimited by the arch of the handle loops when the latter is of sufficient size.

A final example of a variant of the method according to the invention shown in FIGS. 23 and 24 consists in producing the first two winding (s) 13,24, that is to say the one or those in the direction of the chain above the lining 4 placed or threaded on the retractable mold 1 and to attach over the assembly or the two first winding (s) 13, 24 a preformed sheath 60 of suitable shape and dimensions, produced by a separate assembly 61 of a second strip or strip 62 or for example by a separate winding 63 formed by using the second strip or strip 62 in the weft direction or any other means. This separate assembly 61 or this separate winding 63 or other form is produced by a parallel operation around a shaper 64 by winding or by forming after lateral juxtaposition of the second strip or strip 62. This separate assembly 61 or this winding is then isolated separated 63 from this shaper 64 having a coherence or a self-maintaining and it is threaded or placed on the first winding (s) 13,24 while joining together by gluing or any other means the strips of the first winding (s) with the strip or strip of the assembly 61 or of the separate winding 63. A bag of the same constitution as the previous one is thus obtained, but of greater strength and faster and easier to manufacture since it is carried out in two separate parallel operations.

All the variants described above are possible within the framework of the particular embodiment described above.

Bags, sachets or other containers, manufactured in accordance with the above have the particularities that the mode of execution used of the above method gives them, in particular the different loops serving as handles and the different ways of carrying out the windings.

The containers manufactured in accordance with the method of the present invention are all of a manufacturing cost significantly lower than the cost of manufacturing an identical container obtained by the traditional method, that is to say by assembling woven panels.

It is obvious that the more complicated the container to be manufactured, the greater the general economy of its manufacture if the present invention is implemented.

Claims

1. A method of manufacturing a flexible container, for example intended to receive bulk products, the container being of the type comprising an inner lining or bag (4) consisting of a flexible film, intended to ensure sealing, and a outer bag formed by the interlacing of strips or strips of flexible material, polypropylene or polyethylene, intended to ensure the mechanical strength of the container, said container having a generally tubular or prismatic shape, the two bases (11, 12) of which constitute one the bottom and the other the top of the container, top comprising or constituting at least one lifting handle (33, 48, 50) for gripping, filling and handling the container, process characterized in that the the lining (4) is placed around a retractable body serving as a mold (1) affecting the shape of the container to be produced, in that it covers all or part of the lateral faces (9, 10, 21, 22) and basics (11 , 12) of the lining (4) by at least one first winding (13, 24) with contiguous turns of a strip (8) or of a strip of flexible material, by at least one rotation about an axis ( 14, 14 ', 23, 23') parallel to the bases (11, 12) of the container to be produced, which the side faces of the lining (4) are covered by a second winding (29) of the strip (8) of flexible material by at least one rotation about an axis (26, 26 ') perpendicular to the bases of the container to be produced to ensure the cohesion of the first winding (s) (13, 24), and in that that, simultaneously with each of the abovementioned recoveries, the first strip or strip wound to the lining is secured, then the second strip or strip to the first, and in that the mold (1) is retracted and extracted to release the container formed.

2. Method according to claim 1, characterized in that the phase of first winding (13, 24) with contiguous turns is obtained in two successive operations, the first (13) consisting in covering at least partially two of the lateral faces (9, 10) opposite the lining ( 4) of prismatic shape and at least partly its bases (11, 12), by at least one rotation about an axis (14, 14 ') parallel to the bases of the container to be produced, the second (24) consisting of covering at least partly the two other opposite lateral faces (21, 22) of the lining (4) and at least partly its bases (11, 12), by at least one rotation about an axis (23, 23 ') parallel to the bases (11, 12) of the container to be produced and perpendicular to the first axis (14, 14 ').

3. Method according to claim 1, characterized in that the phase of first winding (13, 24) with contiguous turns is obtained in n successive operations, one consisting in covering at least partially two of the n lateral faces (9, 10) opposite the lining (4) shaped in prismatic form with n lateral faces and at least partly its bases (11, 12), by a rotational movement about an axis parallel to the bases of the container to be produced, the others each consisting of successively covering, two by two, at least in part, the other opposite lateral faces of the lining and its bases, by rotation about an axis parallel to the bases (il, 12) of the container to be produced and which forms a 180 ° / n angle relative to the axis of the previous rotation.

4. Method according to any one of claims 1 to 3, characterized in that one carries out the operation or each of the successive operations of first winding (13, 24) by rotation of the mold assembly (1) / lining (4) around an axis (14, 23) parallel to the bases (11, 12) of the container to be produced, and in that the second winding phase (29) is carried out by rotation of the mold (1) / lining (4) assembly around an axis (26) perpendicular to the bases, the strip (8) or strip distributor (16) remaining fixed in rotation during each of the winding phases .

5. Method according to any one of claims 1 to 3, characterized in that one conducts the operation or each of the successive operations of first winding (13, 24) by rotation of the distributor (16) of strip (8) or strip around an axis (14 ¹ , 23 ') parallel to the bases (11, 12) of the container to be produced, and in that the second winding phase (29) is carried out by rotation of the distributor (16 ) strip around an axis (26 ') perpendicular to said bases, the mold (1) / lining (4) assembly remaining fixed in rotation during each of the winding phases.

6. Method according to any one of claims 1 to 5 characterized in that, during the first winding phase (13, 24) with contiguous turns, comprising two or n operations, the handle (s) is (are) produced simultaneously (33, 48) allowing the gripping, filling and handling of the container (35, 38, 47).

7. Method according to claim 6 characterized in that, during the second winding phase (29), the second winding protrudes from the side faces (9, 10, 21, 22) of the lining on the side of the handle (s) ( s) (33, 48) of the container, while gradually tightening, so as to ensure shaping of the handle (s) (33, 48) by grouping the loops thus formed at least at its ( their) end (s) (37).

8. Method according to any one of claims 1 to 7 characterized in that, during the first winding phase (13, 24) with contiguous turns comprising two or n operations, all of the side faces (9, 10) are covered , 21, 22) and the all of the bases (11,12) of the lining (4).

9. Method according to any one of claims 1 to 7 characterized in that, during the first winding phase (13, 24) with contiguous turns comprising two or n operations, only part of the lateral faces (9, 10, 21, 22) and only part of the bases (11, 12) of the lining (4), in that there is in the uncoated area of at least one of said bases a mold element (39 , 40) intended for producing a chute for the entry or exit of bulk products, then in that the chute is formed (45, 46) during the second winding phase (29), by covering the mold element which corresponds to it, by winding with contiguous turns the strip (8) of flexible material around said mold element.

10. Method according to any one of claims 1 to 9 characterized in that, during the second winding phase (29), the lateral faces (9, 10, 21, 22) of the lining are completely covered (4) by a winding with contiguous turns.

11. Method according to any one of claims 1 to 9 characterized in that, during the second winding phase (29), the side faces (9, 10, 21, 22) are only partially covered with the lining ( 4), the second winding being made at least in places with non-contiguous turns but in sufficient quantity to maintain the cohesion of the first winding (13, 24).

12. Method according to claim 1, characterized in that the retractable mold is flexible and extensible inflated or expanded by a fluid under pressure or filling.

13. Method according to the preceding claim, characterized in that the retractable mold is filled with a finely divided solid material or capable of expansion.

14. Method according to claim 1, characterized in that it consists in making the first winding (s) (13,24), that is to say those in the warp direction using a first strip above the bag enveloping the retractable mold (1) by turns around two crossed axes and to be attached to the assembly with securing a sheath (60) of suitable shape and dimensions, produced separately, by an assembly (61 ) or by a winding in the weft direction on a shaper (64) of a strip or a strip, to release this assembly or this winding separate from this shaper and to thread it or place it on the first windings (13,24) while securing it to the tape turns of the first winding (13,24).

15. Container obtained by implementing the method according to any one of claims 1 to 14, said container being of the type comprising an inner lining (4) and an outer bag of generally tubular or prismatic shape, the two bases (11 , 12) constitute one the bottom and the other the top of the container, top comprising or constituting at least one loop forming a lifting handle (33, 48, 50) for gripping, filling and handling the container, container characterized in that at least part of the lateral faces (9, 10, 21, 22) and of the bases (11, 12) of its lining (4) are covered with at least one first winding (13, 24) and a second winding with contiguous turns of a strip (8) of flexible material, the strips or strips of the first and second windings being secured to each other.

16. Container according to the preceding claim, characterized in that the lateral faces

(9, 10, 21, 22) are entirely covered with a first winding (13, 24) with contiguous turns of a strip (8) or strip of flexible material and at least part of a second winding (29) of a strip (8) or strip of flexible material which crosses the first winding (13, 24) perpendicularly.

17. Container according to the preceding claim, characterized in that the second winding (29) is a winding with non-contiguous turns capable of maintaining the cohesion of the first winding (13, 24).

18. Container according to any one of claims 15 and 16, characterized in that its lateral faces (9, 10, 21, 22) are entirely covered with two windings (13, 24, 29) with contiguous turns of a strip (8) or strip of flexible material which extend in two substantially perpendicular directions.

19. Container according to any one of claims 15 to 18, characterized in that its lifting handle (s) (33, 48, 50) formed (s) at its top is or are obtained (s) by a single winding with contiguous turns of a strip (8) or strip of flexible material.

20. Container according to any one of claims 15 to 18, characterized in that its lifting handle (s) (33, 48, 50) formed at its top is or are obtained by two windings (13,24) with contiguous turns of a strip or strip (8) of flexible material, the general directions of the two windings being perpendicular to each other.

21. Container according to any one of claims 15 to 20 of the type having at least one chute (45, 46) for inlet or outlet of bulk products, characterized in that said chute is covered with at least one winding (29) with contiguous turns of a strip or strip (8) of flexible material.

22. Container according to any one of the preceding claims, characterized in that one realizes the first winding (s) (13,24) on a retractable mold (1), which is formed separately an assembly (61) or a preformed winding (63), crossed with one of the first windings , on a separate shaper (64), which is extracted from the shaper (64) this assembly or this separate winding, and that this thread (61) or this winding (63) is threaded on the first (s) winding (s) (13,24).

23. Container according to any one of the preceding claims, characterized in that the strip (8) is a strip (56) formed by the longitudinal juxtaposition of a plurality of strips.

24. Container according to any one of the preceding claims, characterized in that the strip (56) is in one piece.

25. Container according to claim 22, characterized in that the juxtaposition of the strips is carried out by coextrusion and coplanar union.