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
  • B31B70/005—Making flexible containers, e.g. envelopes or bags involving a particular layout of the machinery or relative arrangement of its subunits
• • 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
  • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
• • 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
  • B31B70/14—Cutting, e.g. perforating, punching, slitting or trimming
  • B31B70/146—Cutting, e.g. perforating, punching, slitting or trimming using tools mounted on a drum
• • 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
  • B31B70/14—Cutting, e.g. perforating, punching, slitting or trimming
  • B31B70/16—Cutting webs
  • B31B70/18—Cutting webs longitudinally
• • 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
• • 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
  • B31B2150/003—Flexible containers made from sheets or blanks, e.g. from flattened tubes made from tubular sheets
• • 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
  • B31B2160/10—Shape of flexible containers rectangular and flat, i.e. without structural provision for thickness of contents
• • 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
  • B31B2160/10—Shape of flexible containers rectangular and flat, i.e. without structural provision for thickness of contents
  • B31B2160/102—Shape of flexible containers rectangular and flat, i.e. without structural provision for thickness of contents obtained from essentially rectangular sheets
• • 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
  • B31B2160/10—Shape of flexible containers rectangular and flat, i.e. without structural provision for thickness of contents
  • B31B2160/106—Shape of flexible containers rectangular and flat, i.e. without structural provision for thickness of contents obtained from sheets cut from larger sheets or webs before finishing the bag forming operations
• • 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
  • B31B70/14—Cutting, e.g. perforating, punching, slitting or trimming
  • B31B70/148—Cutting-out portions from the sides of webs or sheets
• • 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
  • B31B70/14—Cutting, e.g. perforating, punching, slitting or trimming
  • B31B70/16—Cutting 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
  • B31B70/00—Making flexible containers, e.g. envelopes or bags
  • B31B70/26—Folding sheets, blanks or webs
  • B31B70/262—Folding sheets, blanks or webs involving longitudinally folding, i.e. along a line parallel to the direction of movement
  • B31B70/266—Folding sheets, blanks or webs involving longitudinally folding, i.e. along a line parallel to the direction of movement involving gusset-forming

Definitions

• the present invention relates to a bag manufacturing method according to which, from a hose comprising transverse perforation lines delimiting legs of the future bag, two separation steps are carried out along the lines of perforations to separate two bags and a waste remaining on one of the bags between the two legs. It also relates to a machine implementing said method.
• a technique of forming a hose from a sheet of paper roll, to separate sections from this hose and to close one end of the section to form a bag is known a technique of forming a hose from a sheet of paper roll, to separate sections from this hose and to close one end of the section to form a bag.
• the hose may also be made of a plastic part, for example transparent, assembled by gluing with the paper by covering the respective edges.
• Document FR 786 579 shows several examples of this technique. It shows particularly on Figures 7 to 10 a method wherein the paper web is provided at regular intervals with transverse perforation lines, with a single line in the center and two lines respectively opening and base, offset on either side of the central line on each side of the sheet, the bottom line being viewed as arriving after the center line in the direction of paper movement, the opening line being viewed as arriving before the central line.
• Punch lines connect the bottom line and the opening line to the center line obliquely.
• the hose is formed by folding each edge over the central portion and gluing together the two edges along a central junction.
• the thus formed hose passes between a pair of drive rollers which drive the hose at a constant speed.
• the hose passes between a pair of separation rollers rotating with a peripheral speed greater than that of the drive rollers before being driven to a folding device.
• One of the rollers of the pair of separation rollers is recessed over a large part of its periphery so as to come into contact with the other roller only intermittently. During this contact, which occurs between the opening line and the central line, the hose is tensioned between the drive rollers and the separation rollers so as to obtain the separation of a section from the hose to level of the central perforation line and the bottom lines.
• the front part of the section which has just been separated is then grasped by the folding device which rotates with a peripheral speed greater than that of the pair of separation rollers.
• the pair of separation rollers at this time maintains the separated section between the center line and the bottom line, that is to say only the upper part of the section, so that the portion of the section between the line of opening and the bottom line is separated from the section forming a waste.
• the waste is driven downwards by the lower roller of the pair of separation rollers provided for this purpose with pins that are planted in the waste between the center line and the bottom line.
• a rear leg is formed on the section, as well as a front leg at the end of the hose. This front leg will be on the next leg.
• the front and rear legs are located on the same side of the section, that is to say in the lower part.
• the front leg is glued and folded by the folding device to close the front portion of the section.
• the peripheral speed ratios between the drive rollers, the separation rollers and the folding device are generally determined in a fixed manner by mechanical drives from the same drive motor.
• Rear-end waste entry imposes limitations on the speed of operation of the machine. Indeed, the front part of the waste can turn around because it is not maintained. This phenomenon is particularly noticeable with a great length of waste and with a high rate. When the front part turns around, it can cause the detachment of the waste which may then get stuck in the path of its evacuation.
• DE 647 889 shows an identical technique in which the central line is subdivided into two lines, so that the waste forms a complete ring.
• the document FR 829 591 proposes to add a pair of rolls between the pair of separation rollers and the folding device, in order to be able to perform the separation function in place of the folding device. This document also proposes to add a pair of auxiliary rollers between the drive rollers and the separation rollers, by pinching the hose only during the pulling operation.
• the document FR 1 159 929 proposes to distinguish the two separation operations by providing two stations between which takes place the separation between the section and the casing and two other stations between which the second separation between the section and the waste takes place. This arrangement tends to make the manufacturing machine cumbersome and expensive because of the multiplication of the number of stations. It can be applied on a machine whose dimensions have been provided sufficient to accommodate additional stations, which is not the case as standard.
• the invention aims to provide an alternative arrangement that simplifies the construction of the machine implementing the manufacturing process, which allows a compact machine and facilitates the implementation of the method when adjusting according to the size of the bags to be made. It also aims to be applicable on existing machines whose size does not allow to receive additional stations. The invention also aims to solve the problem of waste disposal at high speed.
• the invention relates to a method of manufacturing a bag according to which, from a casing having transverse perforation lines defining a rear end of a first bag and at least one foreleg a second bag following the first between a central line and a bottom line, is carried out in a first step to separate the first and second bag and, in a second step, is separated a waste remaining on one of the bags between the rear end and the front leg, characterized in that the first and second stages are carried out between firstly a first pair of separation cylinders and secondly a second pair of downstream separation cylinders.
• the waste being pinched between the center line and the bottom line between the rolls of the first pair during the first step e to be retained on the second bag and then pinched and torn off by the second pair during the second step, the first pair of cylinders being driven by a peripheral speed lower than that of the second pair at least during the first and second stages.
• the method according to the invention makes it possible to produce the bags according to the same principle as in the prior art, but with only two pairs of separation cylinders, whereas the prior art required at least one additional pair of cylinders to perform the second separation. .
• the machine implementing the method according to the invention can thus be more compact since it uses the same two pairs of cylinders to perform the two separation steps. As a result, it is less expensive by reducing the number of pairs of cylinders and reducing the size of the machine.
• Another advantage is that the waste is carried to the front of the second bag, which allows to grab it from the front for its evacuation. Although it is long, its evacuation n 'is not affected, the long portion lying back and not likely to return or come off. Indeed, in the prior art, when the waste remains attached to the rear of the first bag, the only possibility to grasp is the rearmost part, and it becomes difficult to guide during its evacuation, especially in case of great length of the waste.
• the casing is conveyed upstream of the first pair of cylinders by a pair of drive rollers rotating at a constant peripheral speed referred to as the reference speed, the peripheral speed of the first pair of rolls being less than the speed of the first pair of rollers. reference during the first and second stages.
• the casing is thus retained by the first pair of cylinders, the portion of the casing between the pair of drive rollers and the first pair of cylinders being relaxed and sometimes able to temporarily form a corrugation. This possible ripple is subsequently absorbed when the first pair of rollers no longer clamp the hose.
• the speed of at least one of the rolls of the first pair of rolls is adjusted between the second and the first step so that the clamping of the waste between the rolls of the first pair is synchronized with the clamping and tearing of the first bag by the second pair of cylinders.
• the length of the bag must fit on the machine.
• the length of hose that passes between the pinch on the bag during the first and then the second step substantially corresponds to the distance between the first and the second pair of cylinders. Indeed, during the first step, the pinch by the first pair of rolls takes place at the level of the waste between the central line and the bottom line, to maintain it with the second bag.
• the pinching during the second step takes place when the waste maintained on the second bag is at the second pair of cylinders, so after a course of a substantially fixed distance, which does not depend on the length of the bag.
• the interval between the tightening of the second step and that of the first step for the next bag depends on the length of the bag. It can be therefore advantageous to adjust the rotational speed of the first pair of rollers between the second and the first step to adjust the cycle length of the bag.
• the adjustment of the rotational speed of the cylinders is achieved for example by the use of a synchronous electric motor servo.
• the means for adjusting the speed of the first pair of cylinders can also be used to adapt the peripheral speed during the first and the second step so as to limit the difference with the speed of travel of the hose.
• the speed difference can be adjusted to each type of production, depending on the size of the bags and the nature of the hose material.
• the speed of at least one of the cylinders of the second pair of rolls is adjusted between the second and the first step so that the clamping of the first bag between the rolls of the second pair is synchronized with the nip of the second pair of rolls. waste by the first pair of cylinders.
• the peripheral speed of the second pair of cylinders is always greater than the peripheral speed of the first pair of cylinders during the first and second stages, but evolves freely between the stages and may be faster or slower than the first cylinders and may differ depending on the sizes of the bags.
• the perforation lines further define a rear leg at the rear end of the first bag facing the front leg of the second bag.
• the invention also relates to a bag making machine comprising means for forming a hose having transverse perforation lines defining a rear end of a first bag and at least one front leg of a second bag following the first, separation means for, in a first step, to separate the first and second bag and, in a second step, separate a waste remaining on one of the bags between the rear end and the front leg, the characterized in that the separating means comprise a first pair of separating rolls driven by first driving means, and a second pair of separating rolls driven by second driving means, the separating means being configured to pinch the waste between the rolls of the first pair during the first step and retain it on the second bag while e the first bag is clamped between the second pair of separation cylinders, and to pinch the waste and tear it with the cylinders of the second pair during the second step while the second bag is clamped between the first pair of cylinders of separation, the first and the second driving a peripheral speed to the first pair of cylinders lower than that of the second pair at least during the
• a main cylinder of the second pair of separation cylinders has gripping means for gripping the waste in the second step.
• the gripping means are used to carry the waste in the rotating cylinder which comprises these means. These are classically a row of pins, but it can also be a sucker or an adherent surface. Other means are provided for subsequently removing the waste out of the gripping means.
• the main cylinder of the second pair of separation cylinders comprises a bar for clamping the hose, the gripping means being retractable to be retracted during the first step.
• the same bar performs the clamping during the first and the second step, which requires that the gripping means are retracted during the clamping of the first step.
• the main cylinder of the second pair of separation rollers comprises a first strip pullout to clamp the hose in the first stage and a second tear strip to clamp the hose in the second stage, gripping means being arranged in the environment of the second tear strip.
• Each of the bars is dedicated to one of the steps, which makes it possible to perform both steps during a rotation cycle of the main cylinder.
• the main cylinder of the second pair of cylinders comprises at least two tear-off bars, the gripping means being arranged in the environment of all the tear-off bars or a tear-off bar two to pinch the hose during the first step with a bar not provided with a gripper or with the gripper system retracted and a second tear bar with a gripper operative to pinch the hose during the second step and grab the waste.
• the second driving means it is possible using the second driving means to realize the clamping steps for the first step either with the same or with different webs webs from those used in the second step.
• the two steps may be performed, according to the adopted settings, in less than one revolution of the main cylinder, a turn or more than one turn, allowing a high rate over the entire range format.
• the tear strips can be arranged regularly or shifted differently.
• a main cylinder of the first pair of separation cylinders has a retaining bar for gripping the casing during the first and second stages.
• the clamping on the bar is limited to carrying out the separation steps, which leaves the possibility of giving the main cylinder which carries it or to the pair of rolls a rotational speed without constraint outside these stages.
• the same bar is used for the first and the second stage, which allows a compact realization with a small diameter for the first pair of cylinders.
• a main cylinder of the first pair of separation cylinders has a first holding bar for gripping the hose during the first step and a second holding bar for gripping the hose during the second step. Both stages are realized during the same revolution of the main cylinder, which allows a high rate.
• the two holding bars may be arranged opposite to each other or shifted differently.
• a counter-cylinder of the first or second pair of rollers has an eroded zone, the corresponding drive means being configurable so that the first pull-out bar or the second tear-off bar is opposite the zone eroded intermittently during the rotation of the main cylinder.
• the eroded area may take the form of a groove, a flat or any other shape that locally reduces the radius of the cylinder and extends along a generatrix of the cylinder.
• the counter-cylinder may have several eroded areas.
• Figure 1 is a schematic view of a machine implementing the method according to the invention
• FIG. 2 is a perspective view of a hose on which are represented the limits of the bags to be made;
• Figure 3 is a side view of the hose of Figure 2;
• FIG. 4 is a schematic view of the separation means in a position at the beginning of the first separation step
• Figure 5 is a schematic view of the hose in the position of Figure 4;
• Figures 6 and 7 are views similar to Figures 4 and 5 in a final position of step 1;
• Figures 8 and 9 are views similar to Figures 4 and 5 in a position between the first and the second step;
• Figures 10 and 1 1 are views similar to Figures 4 and 5 in a position at the beginning of the second step;
• Figures 12 and 13 are views similar to Figures 4 and 5 in a position at the end of the second step;
• Figure 14 shows a timing diagram of the rotational speeds of a first and a second pair of rolls.
• a machine is shown schematically in FIG. It comprises successively in the direction of unwinding a feeding device 1 receiving a strip of paper 2 in a reel for unwinding, a perforation station 3 for perforations transversely on the strip of paper 2 which unwinds, a training station d a hose 4, separating means 5 for separating the casing 20 into blanks of successive bags, a folding device 6 for forming the bottom of each bag and a receiving table 7 for stacking the bags made.
• the formation station of the hose 4 ends with a pair of drive rollers 40 rotating constant peripheral speed called reference speed.
• the machine further comprises transport means, not shown, arranged between the various stations for guiding and transporting the hose 20 or the blanks between the stations. Only the separation means 5 are modified in the context of this invention, the other equipment will therefore not be described in detail.
• the casing 20 shown has gussets 21, but it should be understood that the invention also applies to a 20 single hose, for bags provided without gussets.
• the casing 20 has an upper face 22 facing a lower face 23, the faces 22, 23 being interconnected by the lateral gussets 21.
• the hose 20 is made by sticking together the edges of the original paper strip 2, the superposed edges being substantially in the middle 24 of the upper face 22.
• the hose 20 is intended to be separated into a first bag 27, a waste 26 and a second bag 28 according to the first bag 27, knowing that in the next cycle, the first bag 27 will be replaced by the second bag 28 and so on.
• the first bag 27 has a rear leg 232 from the lower face 23 of the hose 20, and defined by a central line 233 in the transverse direction and two oblique lines 234 joining the gussets 21.
• the gussets 21 and the upper face 22 are cut at the same transverse level of an opening line 235 from which the rear leg 232 protrudes rearwardly.
• the second bag 28 comprises a front lug 231 issuing from the lower face 23 of the casing 20, and delimited by the central line 233 in the transverse direction and two oblique lines 234 joining the gussets 21.
• the gussets 21 and the upper face 22 are cut at the same transverse level of a bottom line 236 from which the front lug 231 protrudes forward.
• the portion of hose 20 delimited between the oblique lines 234 and between the bottom lines 236 and opening 235 on the upper face 22 forms the waste 26 which will be extracted.
• the rear leg 232 of the first bag 27 is thus opposite the front leg 231 of the second bag 28.
• the perforation station 3 perforates the entire width of the paper web 2 at regular intervals.
• the perforations extend along the central line 233, oblique lines 234, the opening line 235 and the bottom line 236 delimiting the bags on the upper face 22 and the gussets 21.
• the separation means 5 of the manufacturing machine comprise a first pair of separation cylinders 51 driven by first drive means 53, and a second pair of separation cylinders 52, driven by second drive means 54.
• the cylinders of the same pair in the upper part rotate at the same peripheral speed as the cylinders in the lower part but in the opposite direction, so as to accompany the scrolling the hose 20 between them.
• the first pair of separation cylinders 51 comprises a first holding bar 51 1 and a second holding bar 512.
• the second pair of separation cylinders 52 comprises a first tear bar 521 and a second tear bar 522.
• the holding strips 51 1, 512 and pull 521, 522 are fixed to one main roller of the corresponding pair, in this case on the cylinder opposite the upper face 22 of the casing 20, a Generator direction of the cylinder and forms a projecting portion relative to the surface of the cylinder, so as to form a clamp that clamps the hose during the passage of the bar facing the other cylinder, called against-cylinder.
• the counter-cylinders are smooth. Gripping means 523 in the form of a row of pins are arranged near the second tear bar 522.
• the method implemented by the machine will now be described beginning with an arbitrary position, knowing that each position is also found in the next cycle.
• the process is a succession of cycles, a bag being produced for each cycle.
• first and the second bag 27, 28 are in one piece in the extension of the casing 20.
• the first bag 27 is located between the cylinders of the second pair of cylinders 52 while that the second bag 28 is located upstream of the first pair of cylinders 51.
• the casing 20 moves in the direction of the arrow F1, namely from the first pair of cylinders 51 to the second pair of cylinders 52.
• the pairs of cylinders 51, 52 driven by the first and second drive means 53, 54, bring the first support bar 51 1 into contact with the front leg 231 of the second bag 28 and the waste 26 pinching them between the central line 233 and the bottom line 236 while the first tear bar 521 comes into contact with the upper and lower faces 22, 23 of the second bag 28 by pinching them.
• the differential peripheral speeds of each pair of cylinders 51, 52 namely a peripheral speed lower than the reference speed for the first pair of rolls 51, induce traction between the first and the second bag 27, 28 so as to obtain their separation along the perforations of the central line 233, the opening line 235, oblique lines 236 connecting them, as shown in figures 6 and 7. the rear leg 232 of the first bag 27 is thus formed.
• the waste 26 remains attached to the second bag 28.
• each pair of rollers induce a pull between the waste 26 and the second bag 28 so as to separate them along the lines of oblique perforations 234 and bottom 236, as shown in FIGS. 12 and 13.
• front leg 231 of the second bag 28 is thus formed.
• the waste 26 is rammed forward by the gripping means 523 and discharged with the rotation of the main cylinder, in a manner known per se.
• the folding device 6 glues and folds the front tab 231 on the upper face 22 in order to close the end of the bag. This device is conventional and is not described in more detail here.
• the bars do not exert clamping on the other cylinder of the pair. Also, these periods without positional stress are used to speed up or slow down the rotational speeds of the rolls so that the next nip occurs at the selected time with respect to the position of the hose 20 and the desired speed. These adjustments of speeds are adapted for each length of bag.
• a diagram represents on a first curve of the peripheral position of the first pair of rolls as a function of the scrolling of the roll, on a second curve c2 the peripheral position of the second pair of rolls and on a third curve. the reference position cR for the coil.
• the curves d and c2 are synchronous, the peripheral speed of the second pair of cylinders 52 being greater than that of the first 51.
• the speeds, corresponding to the slopes of the curves are such that the speed of the first curve d is lower than the speed of the second curve c2 and that of the reference curve cR to achieve the separation between the first and the second bag.
• the slopes of the curves d, c2 are always identical to those in the first step P1.
• the cylinders in the lower part rotate at a constant speed and only the speed of the cylinders that carry the bars are adjusted. This results in a lower inertia of the moving part which undergoes accelerations. It is however necessary to provide at least one other engine for the counter-cylinders.
• the invention is not limited to the embodiment which has just been described.
• the bars can be arranged in pairs on one and the other of the cylinders of the same pair. It is also possible to provide only one bar per pair of rolls, the rolls performing two rotations per cycle to perform the pinch for both the first and the second step.
• This solution can be applied to one or both pairs of cylinders. When it is applied to the second pair of cylinders, it is necessary that the gripping means are retractable to be active only during the second step.

Landscapes

• Making Paper Articles (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=52589653

Family Applications (1)

Country Status (4)

Families Citing this family (6)

Family Cites Families (25)

• 2014
  • 2014-12-19 FR FR1462928A patent/FR3030352B1/fr active Active
• 2015
  • 2015-12-18 EP EP15820494.1A patent/EP3233461B1/de active Active
  • 2015-12-18 US US15/537,621 patent/US10792881B2/en active Active
  • 2015-12-18 WO PCT/EP2015/080531 patent/WO2016097310A1/fr active Application Filing

Also Published As

Similar Documents

Legal Events