Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B70/00—Making flexible containers, e.g. envelopes or bags
  • B31B70/003—Opening or distending bags
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B70/00—Making flexible containers, e.g. envelopes or bags
  • B31B70/02—Feeding or positioning sheets, blanks or webs
  • B31B70/04—Feeding sheets or blanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B70/00—Making flexible containers, e.g. envelopes or bags
  • B31B70/26—Folding sheets, blanks or webs
  • B31B70/52—Folding sheets, blanks or webs by reciprocating or oscillating members other than plungers and dies, e.g. by fingers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2150/00—Flexible containers made from sheets or blanks, e.g. from flattened tubes
  • B31B2150/001—Flexible containers made from sheets or blanks, e.g. from flattened tubes with square or cross bottom
  • B31B2150/0016—Flexible containers made from sheets or blanks, e.g. from flattened tubes with square or cross bottom made from already formed bags
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2155/00—Flexible containers made from webs
  • B31B2155/003—Flexible containers made from webs starting from tubular webs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2160/00—Shape of flexible containers
  • B31B2160/20—Shape of flexible containers with structural provision for thickness of contents

Definitions

• the invention relates to a method of forming flexible bags of the kind comprising two walls connected by bellows and closed at one end by a bottom. It also relates to a machine implementing such a method.
• document FR 1 270 400 describes a machine and a process in which a strip is unwound and then formed into a hose.
• the hose is flattened so that it has a first and a second wall, then the hose is sectioned in sections so that at each end of the section remains a tab which extends the first or the second wall.
• the tab is folded and glued by being folded down on the wall other than that from which the tab originates.
• Document FR 786 579 shows several examples of this technique. It shows in particular in FIGS. 4 to 6 a manufacturing process in which the paper strip is provided at regular intervals with lines of transverse perforations, with a line in the center and two lines, offset axially with respect to the central line on each the band.
• the hose is formed by folding each edge over the central part and gluing the two edges between them along a central junction so that that the perforations form two transverse lines offset respectively on one and the other of the faces of the hose.
• the hose thus formed passes between a pair of drive rollers which drive the hose at a constant speed.
• the front part of the hose is gripped by the folding device which includes a drum and a counter-rotating folding roller.
• the drum and the folding roller rotate at a higher peripheral speed than that of the pair of drive rollers.
• the folding roller has a bar capable of gripping the front of the hose against the drum, so that the front part of the hose is pulled and torn apart along the perforations to form a section.
• a rear tab is thus formed on the section, as is a front tab at the end of the hose.
• This front leg will be found on the next section.
• the front tab is folded by the folding device over a glued area to close the front part of the section.
• the roller further comprises a folding blade, placed just behind the bar, which pushes the hose in a clamp carried by the drum so as to fold the hose.
• the hose is formed with bellows which connect the first and the second wall.
• Document WO 2016 097310 A1 shows an example of such bags.
• Document EP 2 864 114 B1 describes an example of a machine implementing such a method.
• a blank is first formed and has two skins connected together along two opposite edges by two bellows. The blank is placed flat on a table, one of the so-called lower skins being against the table, the other skin being on top and the bellows being folded down between the two skins. The blank is driven in translation on the table in a direction parallel to the bellows towards a drum at the periphery of which different stations are distributed.
• First delivery means produce a first fold line at bellows level, and a second fold line at a predetermined mined distance from the first line, in a direction perpendicular to the bellows.
• the discharge means comprise a rotary blade holder and complementary grooves carried by a counter-rotating drum.
• the drum has front gripping means for driving the blank by pinching the front edge of the lower skin.
• the opening roller has suction means which hold the upper skin against the roller after it has passed between it and the drum.
• first lateral pinching means pinch the lateral edge of the blank at the junction between the bellows and the lower skin.
• second pinching means pinch the lateral edge of the blank at the calf of the junction between the bellows and the upper skin.
• the lateral gripping means move away from each other, open the blank and form a fold on the bellows in a radial plane of the drum and the roller.
• the second gripping means release the blank while, following the movement of the drum which drives the blank, spatulas fold the open part towards the center.
• the upper skin folds back at the second fold line.
• second delivery means mark two transverse lines, on either side of the second fold line. One of these lines coincides with the first fold line. Then the two flaps delimited by these fold lines are glued and folded over one another to close the flat bottom and thus form the bag.
• the invention aims to propose a method and a machine for making bags which have the advantage of bags with a square bottom but with production rates close to the production of flat bags.
• the invention relates to a method for forming a flexible bag, the bag comprising a first wall and a second wall superimposed on the first wall, the walls being interconnected along longitudinal edges by two bellows , according to which, successively:
• the first wall is grasped at a predetermined distance from the closed end of the bag by lower clamps mounted on a lower support and the second wall by upper clamps mounted on an upper support and the walls are spread using the clamps,
• the second wall is released by the upper clamps and the closed end is folded down with a reel on the second wall by forming a first fold coming out on the first wall between the lower clamps, a second fold coming out on the second wall between the ends of the ribs, and a third fold returning to the second wall symmetrically at the end of the bag relative to the second fold, thus producing a bottom delimited between the first and the second fold,
• the method being characterized in that during the spacing of the clamps, a rib is formed on the bellows extending from one wall to the other.
• the production of flat bags is followed by a step of forming a special bottom.
• the formation of the ribs creates stiff parts which hold the walls apart before the folding, then when using the bag.
• the bellows fold obliquely on the one hand from the closed end to the ends of the ribs and on the other hand from a fold line internal bellows to the ends of the ribs.
• bags with a rectangular bottom are formed from flat bags. We can thus obtain rates close to those of the production of flat bags with a function similar to that of bags with square bottoms.
• the step of spreading the walls is similar to that in the method of making bags with square bottoms, but it is applied to a bag which is already closed.
• Maintaining the flap is achieved for example by bonding with a meltable adhesive or a solvent adhesive, or by welding when the material is suitable, for example if it is or comprises a thermoplastic material. According to an improvement, it is supported with support means on the second wall after the release of the upper clamps. This facilitates the formation of the third fold by initiating the folding of the second wall on itself.
• a spacing is maintained between the second wall and the first wall over at least part of the width of the bag and over its entire length in order to create an air supply channel from the open end to the closed end.
• the bags closed by the flap are initially formed, they are stacked, then they are unstacked to make the bottom.
• the flat bags can be produced at the optimum rate of the machine that makes them. Stacks of the bags are then taken up, by the number of machines necessary to form the special funds according to the invention.
• the formation of the bottom is carried out in line with the formation of the bag. This avoids the intermediate storage and the unstacking means necessary in the previous embodiment.
• the predetermined distance between the closed end and the first fold, respectively the second fold is substantially equal to the depth of the bellows.
• the bag when open, the bag has flanks formed by the bellows which have the same width as the bottom.
• the invention also relates to a machine for manufacturing flexible bags, the bag comprising a first wall and a second wall superimposed on the first wall, the walls being connected together along longitudinal edges by two bellows, one end of the bag.
• the machine comprising receiving means for receiving in series bags moving in a main direction parallel to the longitudinal edges, the closed end being in front, a lower support for supporting two lower clamps, the lower clamps being arranged for grip the first wall at a predetermined distance from the closed end of the bag, an upper support for supporting upper clamps, the upper clamps being arranged to grip the second wall at a predetermined distance from the closed end of the bag, the support upper and the lower support being arranged to separate the lower clamps from the upper clamps to form a rib on the bellows extending from one wall to the other, a reel to fold the bottom onto the second wall by forming a first fold coming out on the first wall between the lower clips, a second fold coming out on the second wall between the ends of the ribs, and a third fold returning to the second wall symmetrically at the end of the bag relative to the second fold.
• the lower and upper supports are respectively lower and upper counter-rotating cylinders.
• the machine comprises support means for pressing on the second wall after the release of the upper clamps and which include a rule extending in the direction of a generator of the upper cylinder, and actuating means for extracting the rule from the upper cylinder during the folding phase and then retracting it.
• the rule output can be controlled for example by a cam system or by an electric or pneumatic motorized control.
• the reel is produced by a folding cylinder configured to clamp the bag against the lower support. The reel first guides the closed end of the bag towards a neck between it and the first support then tightens the bag at this neck in order to form the folds well, so that the bag is flattened for storage and transport.
• the lower support and / or the upper support comprises suction means for respectively aspirating the first and / or the second wall so as to separate them before gripping by the clamps. This guarantees that the clamps only grip the near wall in order to properly separate the walls.
• the suction means extend upstream of the upper support over a length sufficient to create at least one air supply channel from the open end of the bag to the closed end. These means allow the bag to be filled with air during the separation of the walls at the closed end.
• the suction means comprise a band permeable to air mounted in a loop and against which the second wall of the bag is sucked, the band being driven to pass at the same speed as the bag.
• the band accompanies the movement of the second wall to avoid friction of the latter.
• the strip constitutes one of the walls of a box placed under vacuum, which makes it possible to create the suction through the strip.
• the strip can be perforated at regular intervals.
• the machine comprises a delivery station for marking the walls of the bag according to a first marking at a predetermined distance from the closed end and according to a second marking at the same predetermined distance from the first marking.
• the first marking will then correspond to the first and second fold lines.
• the second marking will correspond to the third fold line.
• the delivery station comprises a delivery cylinder and a counter-cylinder mounted counter-rotating parallel to each other, the delivery cylinder comprising two blades extending along two generators and projecting from the cylinder surface and the counter cylinder having a flexible surface.
• Figure 1 is a schematic side view of a machine according to a first embodiment of the invention.
• Figure 2 is a perspective view of a flat bag before processing according to the method of the invention.
• Figure 3 is a view similar to Figure 2 of the bag having undergone a rib forming step
• Figure 4 is a view similar to Figure 2 of the bag during a folding phase
• Figure 5 is a side view of the bag of Figure 2 at the end of the folding phase
• Figure 6 is a perspective view of the open bag is placed standing near to be filled
• Figure 7 is a view similar to Figure 1 according to a second embodiment
• Figure 8 is a view similar to Figure 2 after completion of the upsetting according to the second embodiment.
• a machine for manufacturing flexible bags comprises a conventional bottom forming station 1 and the detailed description of which is not repeated here.
• a flat bag 2 is provided, the bag 2 comprising, as shown in FIG. 2, a first wall 21 and a second wall 22 superimposed on the first wall 21.
• the walls 21 , 22 are interconnected along longitudinal edges 23 by two bellows 24.
• One end 20 of the bag 2 is closed by a flap 25 from the first wall 21 and glued to the second wall 22.
• the bag 2 is shown with a tongue 26 which extends the first wall 21 beyond the end of the second wall 22 opposite the closed end.
• the invention also applies to the case where the tongue 26 extends the second wall 22, or, more generally, whatever the shape of this end.
• the machine further comprises receiving means 3, a lower support 4, an upper support 5, and a reel 6.
• the receiving means 3 are provided for receiving in series the bags 2 moving in a main direction parallel to the longitudinal edges coming from the bottom forming station 1, the closed end 20 in front.
• the receiving means 3 allow the bags 2 to pass through one by one, at regular intervals until the next step.
• the lower support has the form of a lower cylinder 4 rotatably mounted.
• the lower cylinder 4 supports two lower clamps 41, the lower clamps 41 being arranged to grip the first wall 21 of the bag 2 presented by the receiving means 3 at a predetermined distance from the closed end 20 of the bag 2.
• the lower clamps 41 are aligned on the same generator of the lower cylinder 4.
• the upper support has the shape of an upper cylinder 5 rotatably mounted in the opposite direction to that of the lower cylinder 4.
• the upper cylinder 5 supports upper clamps 51 which are arranged to grip the second wall 22 at the predetermined distance from the closed end 20 of the bag 2. For this, the lower clamps 41 and upper 51 are opposite one another without angular offset.
• the upper clamps 51 are aligned on the same generator of the upper cylinder 5. The gripping of the walls is carried out when the clamps are at the neck between the lower and upper cylinders 4, 5.
• the upper and lower cylinders 4, 5 have suction means 8, for sucking the first and second walls 21, 22 respectively so as to separate them before gripping by the grippers 41, 51.
• These suction means 8 comprise two lower boxes 81 and two upper boxes 82 facing each other upstream of the upper support 5 and, for each box 81, 82, a permeable strip 83, 84 air loop mounted.
• the permeable strip 83, 84 is placed against the box 81, 82 in front of an opening of the latter and is driven to scroll at the same speed as the bag.
• the strip 83, 84 is for example pierced with a row of holes in the middle.
• the box 81, 82 is put under vacuum by means not shown so that the second wall 22 of the bag is sucked against the strip 84 of the upper box 82 and the first wall 21 of the bag is sucked against the strip 83 of the lower box 81
• the length of the boxes 81, 82 is sufficient so that, when the clamps grip the upper and lower walls 21, 22, an air supply channel is created from the open end 21 of the bag to the closed end 20 by the spacing of the walls due to the suction against the strips 83, 84.
• the boxes 81, 82 are placed to vacuum the edges of the walls 21, 22 at the bellows 24.
• the upper support 5 and the lower support 4 are arranged to separate the lower clamps 41 from the upper clamps 51.
• the spacing is obtained by continuing the rotation of the lower and upper cylinders 4, 5 so that the distance between the clamps 41, 51 increases.
• a rib 27 is thus formed on each of the bellows 24 extending from one wall to the other.
• the machine further comprises support means 7 for pressing on the second wall 22 after the upper clamps 51 have been released.
• the support means 7 comprise a rule 71 extending in the direction of a generator of the upper cylinder 5, and actuating means for extracting the rule 71 from the upper cylinder 5 during the folding phase and then retracting it.
• the reel 6 is designed to fold the bottom onto the second wall 22.
• the reel 6 is produced by a folding cylinder 6 configured to clamp the bag 2 against the lower cylinder 4 by being rotated in the opposite direction to the lower cylinder 4.
• the machine implements a process for forming a special bottom on the 2-flat bags.
• the bag 2 After one end of the bag 2 has been closed in the bottom forming station 1 by a flap 25 from one of the walls 21 and glued to the other wall 22, in a manner known per se, the bag 2 is transported in a direction of transport by the receiving means 3, the longitudinal edges 53 of the bag 2 being parallel to the direction of transport F1, towards the neck between the upper and lower cylinders 4, 5, which are counter-rotating.
• the closed end 20 of the bag 2 projects beyond the neck and the suction means tend to separate the first 21 from the second wall 22.
• a channel is created inside the bag along each edge to put in place communication the bottom with the opening of the bag.
• the lower 41 and upper 51 clamps are actuated to grip respectively the first and the second wall 21, 22 at a predetermined distance from the closed end 20 of the bag 2.
• clamps 41, 51 are introduced into the delimited space by the bellows 24. They hold the first wall 21, respectively the second 22, on the lower cylinder 4, respectively upper 5.
• the walls are separated using the clamps 41, 51 to form a rib 27 on the bellows 24 extending from one wall to the other 21 , 22, as shown in Figure 3.
• the cavity thus created is filled with air from the open end through the air supply channels.
• the upper clamps 51 are then controlled to release the second wall 22.
• the rule 71 of the support means 7 is deployed to press on the second wall 22 after the release of the upper clamps 51, as shown in FIG. 4.
• the bag 2 continues its path towards the folding cylinder 6 to fold the closed end 20 of the bag 2 onto the second wall 22 by forming a first fold 281 exiting on the first wall 21 between the lower clamps 41, a second fold 282 exiting on the second wall 22 between the ends of the ribs 27, and a third fold 283 returning to the second wall 22 symmetrically at the end of the bag 2 relative to the second fold 282, thus producing a bottom 29 delimited between the first and the second fold 281, 282.
• the distance between the closed end 20 and the first fold 281, respectively the second fold 282 is substantially equal to the depth of the bellows 24.
• the bag 2 When using the bag 2, it can be opened by the open end, spreading the first and second walls 21, 22, to obtain a shape as in FIG. 6. Depending on the nature of the material of the bag 2, it can stand upright on the bottom 29 created by the method.
• the material may be paper, plastic film or a woven material of thermoplastic material.
• the bags closed by the flap 25 are initially formed, they are stacked, then they are unstacked to make the bottom 29. Unstacking means replace the bottom forming station 1 and feeds the receiving means 3 with the bags one by one.
• the machine differs from that of the first embodiment in that it comprises a delivery station 9 to mark the walls of the bag and facilitate the setting form of it.
• the discharge station 9 is placed upstream of the suction means 8 and comprises a discharge cylinder 91 and a counter-cylinder 91.
• the two cylinders 91, 92 are rotatably mounted parallel to one another and are counter-rotating.
• the discharge cylinder 91 has two blades 911, 912 extending along two generators and projecting from the surface of the cylinder 91.
• the counter-cylinder 92 has a flexible surface, produced for example by a rubber coating, at least opposite blades 911, 912.
• the peripheral speed of the cylinders 91, 92 is that of movement of the bags.
• the blades 911, 912 successively pinch the bag 2 against the counter-cylinder 92 and thus carry out two markings on each bag.
• the first marking corresponds to the first fold 281 and to the second fold 282, while the second marking anticipates the third fold 283, as shown in FIG. 8.
• the preferential distance between the first marking and the edge of the closed end is equal to the depth of the bellows.
• the preferred distance between the second marking and the edge of the closed end is twice the depth of the bellows.

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ID=66049342

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• 2018
  • 2018-12-12 FR FR1872808A patent/FR3089860B1/fr active Active
• 2019
  • 2019-12-11 WO PCT/EP2019/084737 patent/WO2020120616A1/fr unknown
  • 2019-12-11 EP EP19817711.5A patent/EP3894204A1/de active Pending
  • 2019-12-11 US US17/413,220 patent/US11833775B2/en active Active

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