CH634788A5 - MACHINE FOR FORMING, FILLING AND DEPOSITING BAGS FILLED IN CARDBOARDS AND METHOD FOR ACTIVATING THE SAME. - Google Patents

Description

The invention relates to a machine for shaping, filling and depositing bags filled in cardboard boxes, and to the method of actuating this machine.

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The U.S. Patent N ° 3983682 relates to the formation and filling of bags with a particulate material, and to the deposit of filled bags in cardboard boxes, the principle underlying this patent being intended to facilitate the introduction of filled bags into cardboard boxes, a guide formed by two stirrup sections placed face to face being intended to conform the bags filled and suspended by vibrations transmitted to this guide. The guide enters the open upper end of the carton and, therefore, each filling operation must be completed and the filled carton must be removed before the next filling operation can begin, the speed of handling being thus limited. Furthermore, after a bag has been released and fallen into a carton, its speed of descent is delayed by the friction of contact with the guide and by the effect produced by the air cushion inside from the carton, these factors preventing the bag from quickly falling into the carton.

The object of the invention is to eliminate these disadvantages of the machine of the patent cited above so that the speed of cardboarding is increased by about 60%.

To this end, the machine according to the invention is characterized in that it comprises a hollow mandrel disposed vertically and on which a sheet of material is formed into a continuous tube, a device for filling part of the tube above a sealing device, a conveyor located under the sealing device, aligned with the mandrel, and mounted so as to move cartons successively to place them below the sealing device to receive filled bags, a tubular shaping device located below the sealing device, between the latter and the carrier, its upper end being close to the lower side of the sealing device and its lower end being located above of the conveyor, at a level above the upper end of the cartons resting on the conveyor, a device intended to move the parts of the tube situated above the sealing device and having been filled, to put them in a position such that they are below the sealing device while being suspended inside the forming device, the device having a length calculated so that it receives the filled parts of the tube placed under the sealing device in order to give it its transverse profile, a vibrator acting on the shaping device in order to give the suspended part of the tube practically the transverse profile of the setting device form, a device for sealing and cutting the tube suspended above its filled part, so as to form a bag and to release it, and a conveyor movement device intended to ensure that an empty carton is placed in place below the shaping device in synchronism with the release of the filled bag.

A method for activating the machine according to the invention is characterized in that it consists in putting a section of flexible material in the form of a tube, in sealing the tube transversely, in filling part of the tube above the seal by a determined load of particulate matter, to lower the filled part of the tube to put it in a shaping device having a determined transverse profile and, while the bag is retained by being suspended in this device , to produce vibrations so as to bring it to practically match the transverse profile of the shaping device, to put an empty cardboard in place below the shaping device, in alignment with the lower end of the suspended part of the tube, while vibrations are produced, then to cut the tube above its filled part so that the bag thus formed falls from the shaping device into the carton.

The invention will be described in more detail with reference to the drawings annexed by way of example and in which:

fig. 1 is a front view of a vertical forming and filling machine according to the invention;

fig. 2 is an elevation of the machine, seen from the right with respect to its representation of FIG. 1;

fig. 2A is a horizontal section of the forming device and shows the elements for projecting air jets downwards;

fig. 3 is a partial front view on an enlarged scale of the machine and shows the device for shaping the filled bags so that they follow the transverse profile of the carton, as well as the elements for guiding the bags filled in the cartons, this figure also showing the transporter which supports the cartons below the training device in order to allow the bags to be deposited in these cartons;

fig. 4 is a partial elevation seen from the right with respect to the representation of FIG. 3;

fig. 4A is a partial plan view of a conveyor belt designed to convey the cartons so that they are placed at regular distance from each other;

fig. 5 is a partial axial section of the sealing and cutting mechanism;

fig. 5A is a section similar to that of FIG. 5 and shows, in section, the sealing jaws below the cutting blades;

fig. 6 is a horizontal section of a carton and shows the space left free between the bag and this carton, which represents one of the means for evacuating the air;

fig. 7 is a plan view of a narrow conveyor belt intended for conveying the cartons and represents the end flaps or dust protection flaps in the upright position and the two lateral or shutter flaps folded down;

fig. 8 is a plan view of a narrow conveyor belt intended for transporting cartons in which the end or dust protection flaps, as well as one of the side flaps, are straightened, while one of the side flaps shutter is folded down;

fig. 9 is a cross section of the carton shown in FIG. 7 and shows the latter while it rests on the belt and its end flaps or dust protection are straightened, while the two lateral shutter flaps are folded down;

fig. 10 is a plan view of the sealing mechanism of the open top of the bags, and FIG. 11 is an elevation of the device of FIG. 10.

The machine shown in figs. 1 and 2 is a vertical type filling and filling machine, which comprises a frame 10 on which is vertically mounted a hollow filling mandrel 12 on which is directed a sheet of flexible material 14 intended to be formed into a continuous tube on this mandrel; a hopper 16 placed above this tube delivers the material to be conditioned; a lateral sealing element 19 is intended to form a lateral weld joint which is continuous; a mechanism 18 is intended to move the formed tube downwards on the mandrel; a sealing and cutting mechanism 20a, 20b is intended to shape the tube into bag sections and to separate these sections into individual bags; a mechanism 22 is intended to give the tubular bags a transverse profile corresponding to the cross section of the interior volume of the cartons in which they are to be deposited, an element 23 (fig. 3) being intended to vibrate this shaping mechanism and a conveyor 24 being intended to put the cartons in a position allowing them to receive the bags, then to evacuate them.

The cutting mechanism 20a as shown in FIG. 5 comprises two jaws 68, arranged face to face and mounted so as to be able to carry out reciprocating horizontal movements which bring them together and move them away; each of these jaws has a vertical flat surface 70 intended to be applied, on the one hand, against the anterior side and, on the other hand, against the rear side of the tube in order to compress it and seal a short length of this tube , as shown in fig. 5, between the upper end and the lower end of the faces of the jaws. These jaws have a vertical depth sufficient to form a sealed region which is capable of being cut, between its upper and lower limits, in order to form a weld joint at the lower end of the bag, above the jaws, as well as '' a solder joint at the upper end of the bag below the jaws.

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The sectioning mechanism 20b comprises cutting blades 72 which are housed inside the jaws 68 so that they can be moved horizontally when the jaws have been brought together, in order to section the sealed part of the bags. When a structure of this kind is implemented, as soon as the jaws are brought back, the bag located on the lower side of these jaws is released and falls from the shaping device into the carton.

It may be desirable in some cases to leave the top of the bag under the jaws open until the bag is placed in the carton and, in this case, the bottom of the jaws 68 which is under the cutting blades 72 is chamfered, as shown in fig. 5A, so that the sealing is done only above the cutting blades. The tube under these blades is not sealed and, therefore, the section of bag formed by cutting the tube remains open at the top and falls into the carton in which it is brought by a guide. When the operations are carried out in this way, a device 101 is required, as shown in FIGS. 10 and 11, intended to seal the open upper end of the bags while they are in the cartons, after the latter have been evacuated by the conveyor 24 from the position they occupied under the lower end of the mandrel .

The sealing jaws 68 have on the upper side, in the representation of FIG. 5, flat surfaces 74 on which the lower end of the bag located on either side of the weld joint is intended to rest during filling; the sequence of operations in the machine is carried out in such a way that the sealing jaws 68 are held in application against the bottom weld joint until the bag is completely filled, and for a period of time long enough to allow the weld to be completed and set before these jaws are brought back to allow the bag to fall into the carton below it. The advantage as mentioned lies in the shaping of a bag so that its transverse profile is constant over its length. As a result, the filling volume is maximum and the length of the bag is also maximum.

When the tube has been sealed transversely, so as to form the bottom of a bag, and the part above the solder joint has been filled with a predetermined amount of particulate material, the tube is lowered and put in a position where its filled part is inside the tubular shaping device 22 (whose transverse profile corresponds substantially to the cross section of the interior volume of the carton in which the bag is to be placed) and, while it is suspended in this device, this bag is caused to vibrate so as to conform to the shape of the interior volume of the cardboard, then this bag is sectioned so as to be separated from the part of the tube situated above it and, finally, it falls by gravity into the box resting on the carrier.

In the machine described in the aforementioned US patent, the forming device 22 enters the open portion of the carton and must be raised to allow a filled carton to be removed. The operating speed is therefore limited, which slows down the production speed. Furthermore, shaping the bags so that they exactly match the cross-sectional profile of the interior of a carton has the effect of trapping the air present in it during the deposition of the bag and , since this air prevents the bags from immediately resting on the bottom, the speed of cardboarding is thus limited. The impossibility for the bags to deposit quickly on the bottom of the cartons in front of which they were was further aggravated by the friction of their surface in contact with the inner sides of the cartons. The device for forming or shaping the machine according to the invention is designed so as to eliminate these drawbacks, this device being raised or the conveyor being lowered so that the open upper end of the cartons resting on the conveyor is placed at a distance below the lower end of the forming device, so that the bottom of the bags suspended in this device is also at a distance above the open top of the carton. In addition, air jet projection elements are mounted so as to disengage the bags from the forming device and, moreover, the machine is designed so as to evacuate the air from the cartons when the bags fall into them. .

The device 22 for forming, as shown, comprises two profiles 26 in stirrup which are arranged face to face and which are placed below the sealing and cutting mechanism and above the open top of the boxes resting on the conveyor 24 placed below. Each of the stirrup sections 26, as shown in FIG. 2A, comprises a lateral partition 28 as well as anterior and rear partitions 30 forming a right angle with the previous one, these partitions being intended to be applied against the anterior side, the rear side and the lateral sides of the filled bag. The stirrup profiles 26 are supported, between the front ends of two horizontal arms 32 placed transversely at a distance from each other, by angle brackets 34 whose vertical arms are fixed to the stirrup profiles, and the horizontal arms are mounted in an adjustable manner at the anterior end of the arms 32, in order to be displaceable transversely and to make it possible to modify the space separating these profiles in stirrup and, consequently, the transverse area delimited by the latter. The rear end of the arms 32 is fixed to a mounting panel 36 by means of relatively thick blocks 38 of elastomer placed between them and the chassis. The upper end of the shaping device is located just below the lower side of the sealing and cutting mechanism, and its lower end is placed above the conveyor at a level above the upper end of the carton resting on the carrier. Orientable deflectors 40 arranged on the sides opposite to the lower end of the forming device are mounted so that they can be lowered into the upper end of a cardboard supported below, in order to retain the closure elements 42 located at the top of the carton so that they are folded outwardly from this summit, these deflectors being intended to guide the bag into the open end of the carton. These deflectors 40 can be oriented on shafts 44 on which they are mounted and, for their part, these are rotatably mounted on the chassis of the machine by means of brackets 45 fitted with bearings 46 and 48. The brackets 45 are fixed by bolts 50 mounted in buttonholes 52 on a cross-member 54, so that they can be moved transversely so as to be close and distant from each other, and the opposite ends of the cross-member 54 are fixed to uprights 56 by means of bolts 58 passing through buttonholes 60 which make it possible to adjust the position of the deflectors up and down. The deflectors 40 are brought into the working position and are moved away from them by rotation of the shafts 44; the rotation of these is controlled by arms 62, one end of which is fixed to one of these shafts and the other end of which is fixed to the rod 64 of the piston of pneumatic cylinders 66. The deflectors are retained in the withdrawal position until a carton is brought into position, and they are immediately removed when the bag falls into the carton.

The shaping or forming device is made to vibrate while the bag is suspended therein and while the part of the tube which is above the sealing and cutting mechanism is being filled, in order to give the bag filled the cross section profile of this training device. The vibration of this device is produced by a vibrator 23 bolted to the mounting panel 36. As mentioned previously, this panel is fixed to the chassis by means of rubber blocks placed between it and this chassis in order to allow this panel, and therefore the training device, to undergo significant tremors.

The lower end of the forming or training device is placed at a sufficient distance above the conveyor, so that the cartons can be put in place and evacuated under the lower end of this training device while a filled bag is suspended in this device and the part of the tube above the sealing and cutting mechanism is being filled. Thus, it is possible to speed up the packaging by placing the cartons in the loading position and removing them5

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gaining from this position without having to wait for the removal of the training device.

According to one embodiment, the forming device 22 has a transverse profile which corresponds substantially to that of the internal volume of the carton, so that a bag to which the profile of the forming device has been imparted slides gently in the open top of the carton . However, it is desirable in practice to give the transverse profile of the forming device slightly smaller dimensions than those of the cross section of the interior volume of the carton; this profile is obtained by means of the adjustable mounting of the stirrup sections 26 which constitute the training device, that is to say that the relative position of these sections is adjustable. The reduction of the transverse profile of the forming device, and therefore that of the bag before it falls from this device into the carton, makes it possible to obtain a narrow clearance a as shown in FIG. 6, this play around the bag, between the latter and the carton, avoiding frictional contact between the sides of this bag and the inner sides of the carton, since it has been observed that this friction tends to delay the entry of the bag into the cardboard. The air trapped between the bottom of the bag and the bottom of the carton, and tending to prevent this bag from going down freely in the latter, can thus escape upwards around the bag. The air in the carton can be removed from the bottom of the carton, as shown in Figs. 7, 8 and 9. In the representation of figs. 8 and 9, the strap 92 is narrow and the cardboard is placed on this strap in such a way that the end or dust protection flaps rest on the strap and the side or closing flaps are folded down . The space between the adjacent ends of the dust protection flaps allows the air to escape. As shown in fig. 9, the cardboard is placed on the belt with the dust protection flaps and one of the shutter flaps resting on this belt and with the other shutter flap folded down. The space between the dust protection flaps, which is left exposed by the shutter flap folded down, allows the air to escape.

The slight reduction in the transverse profile of the bag to eliminate friction contact with the inner surface of the cardboard, the provision of an air exhaust space around the bag and the provision of an exhaust passage air at the bottom of the carton collectively promote the rapid descent of the bag into the carton; it is therefore possible to increase the speed of cardboarding, so that it can be carried out during the time interval necessary to deposit the particulate matter in the bag above the sealing and cutting mechanism, the speed of cardboarding is thus limited only by the speed at which the bag can be filled with this particulate material. This factor is particularly important when the bags are filled with a light and bulky particulate matter whose descent is delayed, on the one hand, by friction and, on the other hand, by the mixing of the air trapped in the inside the box when the bag goes down into it.

The frictional contact of the filled bags with the internal surface of the shaping device 22 sometimes restricts the freedom of descent of this filled bag. So, as shown in fig. 2A, elements for projecting a jet directed downwards, on the front side and on the rear side, are produced in the form of tubes 90 arranged vertically, placed in the space between the stirrup sections and having holes 93 oriented downwards, spaced apart from one another vertically and by which air jets are projected downwards against the front and rear sides of the bag.

The conveyor 24 which puts the empty cartons in place under the shaping device and evacuates the filled cartons consists, according to one embodiment, of a ribbon or a belt 92, as shown in FIGS. 3 and 4, part of which is supported longitudinally by rollers 94 spaced apart lengthwise and as shown in FIG. 1; the rollers at one end are driven continuously or intermittently by being suitably connected to a motor M. When these rollers are driven continuously, a positioning device 96 is automatically put in place, across the conveyor, so as to stop a cardboard directly below the shaping device in synchronism with the control of the bag sectioning members so that this cardboard is in place, when a bag is released, to be able to receive it. A stop 98 is brought across the conveyor, so as to clamp the carton against the parapet placed on the rear side of this conveyor in order to stop the following carton. A pneumatic circuit for controlling the positioning device and the stop is supplied with air by distributors 104, 106. Alternatively, the conveyor belt (or the belt) can be moved intermittently, by means of a po-sioning mechanism, in order to bring the cartons in place, each in turn, under the shaping device. When a positioning mechanism is used, the belt is fitted with cardboard holding devices at regular distances. For example, the transporter may consist, as shown in FIG. 4A, in a belt 92 fitted with spacers 92.1 placed at a distance from each other in the direction of the length and intended to receive the cartons and to keep them at a predetermined distance. Parapets 108, placed vertically at a distance from each other in any suitable form on the opposite sides of the conveyor, are intended to guide the cartons and to prevent them from overturning.

When the bags are left open at the top until they are placed in the carton, it is necessary to provide, as mentioned above, a device 101 for sealing their open end, a mechanism 107 for folding the sealed end of the bag in the carton and a mechanism for closing the end flaps and the side flaps for closing the carton. Figs. 10 and 11 represent these mechanisms and illustrate a carton containing a bag discharged by the conveyor 24 from the lower end of the shaping and filling mechanism, this carton being transported to the right,

in the representation of fig. 11, with the front and rear shutter flaps in a separated position to which they are brought by parallel folding bars 111 placed at a distance from one another. The sealing device 101 comprises jaws 113, similar to those shown in FIGS. 5 and 6A, mounted so as to perform reciprocating movements in a horizontal plane above the line of the top of the containers moving along the conveyor. The open top of the bags is brought between the jaws apart and, at the desired time, a detector consisting of a photoelectric cell PC causes the jaws to close against the top of the bag projecting upward, so as to seal it. When these jaws approach each other, they push the shutter flaps of the end partitions away from each other and retain the anterior shutter flap in the pushed-down position. and, when the jaws are brought back, a pneumatic pusher 115 is pushed against the front flap, as shown in FIG. 11, so as to be placed in a substantially horizontal position, so that, when the cardboard continues to advance along the anterior closure flap, it comes into contact with the lower surface of profiles 117 placed at a distance from one the other so as to prevent it from getting up. A folding blade 119 having an inclined edge 121 and supported above the line of movement of the upper end of the boxes is intended to fold the sealed top of the bag projecting upwards, so that it is placed flat inside the open top of the carton. An adhesive is deposited simultaneously on the lower side of the closure flap at the rear of the carton, by means of two rollers 123a, 123b, the lower roller 123a removing adhesive from a tank 125. A mechanism 127, mounted on the beyond the folding and glue depositing elements, is intended to be applied against the lower side of the front flap in order to bring it back and fold it over the top of the carton. At this instant, the front end of the cardboard intercepts a ray projected onto another photoelectric cell P'C 'and a clutch 131, controlled by an electromagnet so as to make a turn, places a hook 133 under the shutter flap rear so as to fold it forwards and downwards over the open top of the carton and, in this way, the front flap and the rear flap both come under a profile 135. During the subsequent movement of the carton , the front and rear shutter flaps enter

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in contact with folding profiles 137, placed at a distance from each other, having the function of first folding inwards the rear closure flap coated with adhesive over the flaps of end, then fold the front shutter over the adhesive-coated top side of the back shutter.

Folding and sealing of the element or obturation elements folded down at the bottom of the cartons is carried out by means of adhesive deposition members, as described above, coating this element or these elements with shutter folded down, then the boxes are brought on folding profiles as described above and are placed under a retaining profile down to fold the element or the shutter elements up and against the bottom.

During an individual operating cycle, a bag is shaped above the sealing jaws, closed at the bottom end and open at the top end, and a bag is formed below the sealing jaws , the latter bag being closed at the lower end and being able to be closed or open at the upper end. The filling operation takes place while the sealing jaws are closed and the cutting takes place after the sealing operation. After filling, the sealing jaws and the cutting blades are brought back, the released bag can fall into the carton placed under it and the filled bag is lowered so that the sealing and sectioning operations of the bag are carried out. following. The bag is caused to vibrate while it is inside the guide. When the top of the bag is left open, it is subsequently sealed while it is in the carton and the latter is evacuated from the mandrel, then the closure flaps are folded over the top of the cartons.

The different operations, namely filling, sealing 5 followed by sectioning, advancing the deflectors at the lower end of the forming or shaping device, the projection of the air jets, the movement of the conveyor and the control of positioning devices and doors, are all controlled synchronously, and in the proper sequence, to ensure that the bag is filled with a predetermined amount of particulate matter, then sealed and sectioned, and then shaken for an interval long enough for it to follow the transverse profile of the shaping device, for this bag to be released in order to be placed in the cartons and for a carton to be placed in time to receive the bag when it falls from the shaping device, the sequence of operations can be controlled by limit switches, or by a perforated tape, or by a combination of limit switches urse and perforated tape, or by equivalent means.

The essential advantages of the machine according to the invention over that of the aforementioned US patent No. 3983682 lie in an increase in the speed of cardboarding of about 60% compared to that which was possible with the machine of the patent. above, and in the elimination of interruptions caused by a bag which does not fall freely from the shaping device and / or which does not descend into the carton.

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Claims (22)

634788 1. Machine for shaping, filling and depositing bags filled in cardboard boxes, characterized in that it comprises a hollow mandrel (12) arranged vertically and on which a sheet of material (14) is formed of a continuous tube, a device (16) for filling part of the tube above a sealing device (20a), a conveyor (24) located under the sealing device, in alignment with the mandrel , and mounted so as to move cartons successively to put them in place below the sealing device to receive the filled bags, a tubular shaping device (22) located below the sealing device (20a ), between the latter and the conveyor, its upper end being close to the lower side of the sealing device and its lower end being situated above the conveyor, at a level located above the upper end of the cartons resting on the conveyor, a device (18 ) intended to move the parts of the tube located above the sealing device, and having been filled, to put them in a position such that they are below the sealing device while being suspended inside the shaping device (22), the device (22) having a length calculated so that it receives the filled parts of the tube placed under the sealing device (20a) in order to give it its transverse profile, a vibrator (23) acting on the shaping device (22) in order to give the suspended part of the tube practically the transverse profile of the shaping device, a device (20a, 20b) for sealing and cutting the tube hanging from the above its filled part, so as to form a bag and to release it, and a device (94) for moving the conveyor intended to ensure that an empty carton is put in place below the delivery device form in synchronism with the release of the filled bag. 2. Machine according to claim 1, characterized in that it comprises members (72) for cutting the tube in the sealed part, between the part of the tube located above the sealing device (20a) and the suspended part of the tube located under the sealing device, so as to make a bag sealed at the top. 3. Machine according to claim 1, characterized in that it comprises members (94) intended to move the conveyor, and members (96) controlled in synchronism with the bag release device so as to stop a carton in a position where he can receive the filled bag and then release it. 4. Machine according to claim 1, characterized in that it comprises a mechanism for moving the conveyor at certain time intervals, so as to put a carton in a position where it can receive a filled bag when the latter is released and then move this carton beyond this position by simultaneously placing an empty carton at said position. 5. Machine according to claim 1, characterized in that it comprises members (32, 34) intended to allow to vary the transverse profile of the shaping device (22). 6. Machine according to claim 1, characterized in that it is equipped so as to cause the evacuation of the air being in the carton during the deposition of the bag in the latter. 7. Machine according to claim 1, characterized in that the shaping device (22) has a transverse profile smaller than the cross section of the interior of the carton, so that there is a clearance (a) between the interior surface of the carton and the sides of a filled bag when it enters this carton. 8. Machine according to claim 7, characterized in that the means for evacuating the air from the interior of the cartons consist in giving the transverse profile of the bag a section smaller than that of the interior of the carton. 9. Machine according to claim 7, characterized in that it is produced so as to provide an air discharge opening at the bottom of the carton. 10. Machine according to claim 1, characterized in that the conveyor (92) is produced so as to carry the cartons so that the end closure elements of the latter rest on it and that one of the lateral elements shutter bottom is folded down while being away from this bottom. 11. Machine according to claim 1, characterized in that the conveyor (92) is produced so as to carry the cartons so that their end closure elements rest on it and that their lateral closure elements are folded towards the bottom, each on one side. 12. Machine according to claim 1, characterized in that the shaping device (22) is fixed on a support panel (36) elastically mounted, and in that the vibrator (23) is mounted on the support panel (36). 13. Machine according to claim 1, characterized in that it comprises a mounting panel (36) and elastomer blocks (38) which support this panel, said shaping device (22) and the vibrator (23 ) being fixed on the panel (36). 14. Machine according to claim 1, characterized in that members for releasing the bag from the shaping device consist of pipes intended to project air jets downwards and against the sides of the bag while the latter is suspended in the shaping device. 15. A method of actuating the machine according to claim 1, characterized in that it consists in putting a section of flexible material in the form of a tube, in sealing the tube transversely, in filling part of the tube above the seal by a determined load of particulate matter, to lower the filled part of the tube to put it in a shaping device having a determined transverse profile and, while the bag is retained by being suspended in this device , to produce vibrations so as to bring it to practically follow the transverse profile of the shaping device, to put an empty cardboard in place below the shaping device in alignment with the lower end of the hanging part of the tube while vibrations are produced, then cutting the tube above its filled part so that the bag thus formed falls from the shaping device into the carton. 16. Method according to claim 15, characterized in that it consists in sealing the bag above its filled part and, simultaneously, in cutting it so as to close off the top of the bag. 17. The method of claim 15, characterized in that it consists in removing the filled cartons from the lower end of the shaping device and putting the empty cartons in place under the shaping device in synchronism with the sectioning of bags. 18. Method according to claim 15, characterized in that it consists in moving the cartons along a determined path, under the lower end of the shaping device, and in intercepting the cartons intermittently when they arrive under the shaping device, in synchronism with the sectioning of the bag, so that it falls from the shaping device into the intercepted cardboard. 19. The method of claim 15, characterized in that it consists in evacuating the air from the cartons placed under the shaping device when the bags are deposited there. 20. Method according to claim 19, characterized in that it consists in evacuating the air from the cartons by their lower end. 21. The method of claim 19, characterized in that it consists in folding at least one of the lateral obturation elements downward, in order to allow the evacuation of air through the space between the ends. shutter elements. 22. Method according to claim 15, characterized in that it consists in projecting air jets down against the sides of the bag, in order to release it when it is in the shaping device.