EP3996905A1

EP3996905A1 - Method for folding a corrugated cardboard blank intended to form a folded box

Info

Publication number: EP3996905A1
Application number: EP20739349.7A
Authority: EP
Inventors: Maxime BRENAUT; Guillaume MARTIN-BASTENAIRE
Original assignee: Bobst Lyon SAS
Current assignee: Bobst Lyon SAS
Priority date: 2019-07-11
Filing date: 2020-07-09
Publication date: 2022-05-18
Also published as: JP7445739B2; JP2022540222A; US20220266562A1; CN114080319B; CN114080319A; US11975502B2; WO2021005139A1; KR20220034168A

Abstract

The invention relates to a method for folding a corrugated cardboard blank (1) intended to form a folded box, the method comprising the following successive steps: i) supply of a blank (1) comprising at least one longitudinal score (11); ii) application of a liquid to the longitudinal score (11) so as to make the corrugated cardboard more flexible at the location of the longitudinal score (11), the application being performed by means of a liquid application arrangement (130) comprising a liquid-ejecting nozzle (134) provided with a liquid outlet; iii) folding the blank (1) around the longitudinal score (11); wherein liquid suction is carried out within a suction compartment (163) of the liquid application arrangement (130) during step ii). The suction makes it possible to remove any excess liquid which might not have been absorbed by the cardboard and/or the cardboard dust produced.

Description

DESCRIPTION

TITLE: Folding process of a corrugated cardboard blank intended to form a folded box

The present invention relates to the field of the manufacture of packaging, and in particular of packaging made from cardboard blanks.

In particular, the present invention relates to the method and to the machine which produces, from a cardboard blank already upset, the folding of two side flaps coming to fold in the direction of a central line, with a partial overlap of the outer edge of these shutters.

State of the art

In the packaging industry, cardboard boxes, or boxes, are commonly made from plate elements in the form of sheets of cardboard or corrugated cardboard. The sheet elements can be processed in a continuous flow in a packaging manufacturing machine in which they are printed, cut and upset, then folded and assembled by gluing, so as to form the cases. In another type of packaging industry, the packaging manufacturing machine is a folder-gluer, the plate elements being printed and cut beforehand.

In the packaging manufacturing machine, a folding-gluing unit performs combined folding-gluing operations of cardboard blanks, along a path which follows the longitudinal axis of the folding-gluing unit. During these processing operations for each cardboard blank, positional deviations of the two flaps are regularly encountered once they are folded and glued, relative to their desired position. These deviations may in particular be due to incorrect lateral alignment of the fold lines. This incorrect lateral alignment generally occurs due to the stiffness of the cardboard and due to the presence of the corrugated support layer which aligns the position of the fold lines on the corrugations. When folding the side flaps of the cardboard blank onto the central flap, this incorrect lateral alignment generates a gap defect between the edges of the side flaps. In the end, this gap produces a deformation of the box.

To remedy this problem and to limit variations in the gap, documents US 2013/0184135 and WO 2017/121503 describe an application of a liquid by means of an ejection nozzle on the upsets of the cardboard blank, beforehand at the folding step. This liquid makes it possible in particular to soften the material at the location of the

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SUBSTITUTE SHEET (RULE 26) upsetting, which facilitates bending and prevents incorrect lateral alignment of the bend lines. However, this solution has the drawback of forming a mist when the liquid comes into contact with the cardboard. This mist then settles on the parts of the machine located near the ejection nozzle and mixes with the cardboard dust. The mixture of solution and dust obtained can therefore potentially clog the nozzle, which leads to poor or no application of the liquid to the delivery lines and, in fact, the lack of gap making the folding ejection nozzle ineffective. downstream. In addition, the resulting mixture of solution and dust disperses in the environment of the folding-gluing unit of the machine, which can cause deterioration of the driving means.

Summary of the invention

The present invention therefore aims to provide a method of folding cardboard blank and a folding-gluing unit that does not have the aforementioned drawbacks.

An object of the invention relates in particular to a method of folding a blank of corrugated cardboard, intended to form a folded box, the method comprising the following successive steps:

i) feeding with a blank comprising at least one longitudinal upsetting;

ii) application of a liquid on the longitudinal upsetting so as to make the corrugated cardboard more flexible at the location of the longitudinal upsetting, the application being carried out by means of a liquid application device comprising an ejection nozzle liquid provided with a liquid outlet;

iii) folding of the blank around the longitudinal upsetting;

wherein a liquid suction is carried out inside a suction compartment of the liquid application arrangement during step ii).

The aspiration makes it possible to remove any excess liquid which would not have been absorbed by the cardboard, whether or not accompanied by cardboard dust produced upstream of the folding-gluing unit or during the impact of the liquid with the cardboard .

The method of the invention may include one or more of the following characteristics:

the suction is carried out discontinuously,

the excess liquid sucked in and / or the dust sucked in are evacuated to a liquid recovery tank,

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SUBSTITUTE SHEET (RULE 26) the method comprises an additional step of cleaning the ejection nozzle so as to remove any deposit of liquid and / or dust at least partially covering the liquid outlet of the nozzle,

the cleaning step is carried out by blowing air at the level of the liquid outlet,

cleaning is carried out discontinuously

the air blowing is carried out by means of an air blower supplied with compressed air.

Another object of the invention also relates to a folding-gluing unit for the manufacture of folded corrugated cardboard boxes implementing the folding method as described above, comprising:

at least one drive device configured to drive corrugated cardboard blanks provided with at least one longitudinal upsetting,

at least one conveyor configured to move the corrugated cardboard blanks in a longitudinal direction from the drive device,

at least one liquid application arrangement configured to apply liquid to the longitudinal discharge, the liquid application arrangement comprising an ejection nozzle provided with a liquid outlet, at least one suction device configured to generating negative pressure within a suction compartment of the liquid application arrangement, and configured to suction liquid,

at least one folding device configured to fold the blank around the longitudinal upsetting.

Alternatively, the application arrangement comprises a guide plate configured to contact a lower face of the cardboard blanks. The guide plate may include an opening or a slot, through which the liquid ejected from the nozzle can exit, and at least one suction opening configured to suck the liquid and juxtaposed with the opening or the slot.

The folding-gluing unit according to the invention may further include a cleaning device configured to remove any deposit of liquid and / or dust at least partially covering the liquid outlet of the ejection nozzle. The cleaning device may include an air blower supplied with compressed air.

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SUBSTITUTE SHEET (RULE 26) Brief description of the figures

The invention will be better understood with the aid of the detailed description which is set out below with reference to the appended figures in which:

[Fig. IA] is a plan view of a cardboard cutout;

[Fig. 1B] is a top view of a folded and glued box obtained from the blank shown in FIG. 1;

[Fig. 2] is a perspective view of a folding-gluing unit intended for the production of folded corrugated cardboard boxes from a cardboard blank according to FIG. 1;

[Fig. B] is an enlarged perspective view of a detail of the fold-glue unit shown in FIG. 2;

[Fig. 4] is a perspective view of the liquid application arrangement fitted to the folding-gluing unit shown in FIG. 2;

[Fig. 5] is a cross-sectional view along the mid-plane P of the liquid application arrangement shown in FIG. 4;

[Fig. 6] is an overall schematic view of the liquid application unit shown in FIG. 4 and related devices;

[Fig. 7] is a perspective view of a cardboard blank as it is processed in the folding-gluing unit of FIG. 2;

[Fig. 8a] is a cross-sectional view along the median plane P 'of the folding-gluing unit as shown in FIG. 4, when introducing a new cardboard blank;

[Fig. 8b] is a view similar to FIG. 8a, at the start of the liquid ejection step on the cardboard blank;

[Fig. 8c] is a view similar to FIG. 8a, at the end of the liquid ejection step on the cardboard blank.

Detailed description of the invention

Fig. 1 shows a cardboard blank 1 used for the manufacture of a folded box T, as shown in FIG. 2, and intended to supply a folding-gluing unit according to the invention. The cardboard blank 1 has a generally rectangular shape flat with two sides of greater length, forming the front edge 2 for the side which enters the fold-glue unit first and the rear edge 3 for the side which enters. the last in the folding and gluing unit. During the advance of the blank 1 in the folding-gluing unit in the direction and the direction of the arrow A, this front edge 2 and this rear edge 3, which are parallel to each other, are generally orthogonal to the longitudinal axis XX 'of the folding-gluing unit. The two lateral sides of smaller

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SUBSTITUTE SHEET (RULE 26) length define the right edge 4 and the left edge 5 which are parallel to each other and to the longitudinal axis XX 'of the folding-gluing unit. The right edge 4, respectively left 5, is the lateral side which is located to the right, respectively to the left, of the longitudinal axis XX 'of the folding-gluing unit. The left edge 5 has a cutout along its two end portions so as to delimit a tab 14 in the central portion of the left edge 5.

Two upsets 12 parallel to the front and rear edges 2, 3 define a central portion 1a of the cutout 1 which is intended to form the peripheral face 21 of the folded box 1 ', the central portion 1a being disposed between a rear portion 1b, which is intended to form the lower face 22 of the folded box 1 ', and a front portion the, which is intended to form the upper face 23 of the folded box 1'. The blank 1 further comprises two pairs of upsets 11 and 11a which are parallel to the right and left edges 4, 5, as well as to the corrugations or grooves 10 of the corrugated layer of the cardboard constituting the blank 1. These upsets 11, 11a extend over the entire width of the central portion 1a. One of the upsets IIa adjoins the tab 14, while the other upsetting 11a, called the central upsetting, is aligned with the longitudinal axis XX '. One of the upsets 11 is arranged between the right edge 4 and the central upsetting 11a, while the other upsetting 11 is arranged between the left edge 5 and the central upsetting 11a, the distance separating this last upset 11 from the central upsetting 11a being equal to the distance of the first upsetting 11 with the right edge 4.

In the extension of the upsets 11 and of the central upsetting 11a, the rear and front portions lb, the are cut so as to form slits 13 extending over the entire width of the rear and front portions lb, the. The slits 13 thus respectively define two pairs of flaps in each of the rear and front portions lb, the, respectively a first pair of large lower flaps 6b-6b ', a second pair of large upper flaps 6c-6c', a first pair of small lower flaps 7b-7b 'and a second pair of small upper flaps 7c-7c'. The large lower and upper flaps 6b, 6c and 6b ', 6c' are respectively arranged on either side of a large central flap 6a and 6a '. Similarly, the small lower and upper flaps 7b, 7c and 7b ', 7c' are respectively arranged on either side of a small central flap 7a and 7a '.

As illustrated in Figs. 1 and 7, the upsets 11 and 11a and their slits 13 will make it possible to fold the blank 1 into a folded box 1 'in the form of a rectangle, each upsetting 11 defining a fold line. The folded box ′ folded flat in the fold-glue unit 100 exits the packaging machine. This folded box 1 'is obtained in particular by folding 180 ° towards the inside of the blank 1 and

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SUBSTITUTE SHEET (RULE 26) around the fold lines 11 of a first set formed by the flaps 6a, 6b and 6c and a second set formed by the flaps 7a ', 7b' and 7c '. These first and second sets are designated respectively by the terms left flap and right flap, and the set formed by the flaps 7a, 7b, 7c and 6a ', 6b', 6c 'is for its part designated by the term part central. The large central left flap 6a accompanied by the large upper flap 6c and the large lower flap 6b is bent at 180 ° with respect to the left push-up 11 and the small central right flap 7a 'accompanied by the small upper flap 7c' and the small lower flap 7b 'is bent at 180 ° with respect to the right-hand delivery 11. FIG. B represents a folding-gluing unit 100 according to the invention. This folding-gluing unit 100 makes it possible to produce blanks T, as defined above, from blanks of cardboard 1 having a configuration similar to that shown in FIG. 1. This folding-gluing unit 100 comprises in particular a first folding module 101 disposed to the left of a longitudinal axis XX 'and a second folding module 102 disposed to the right of the longitudinal axis XX', the first and second folding modules 101, 102 being symmetrical to one another with respect to the axis XX '.

Each of the folding modules 101, 102 particularly comprises an upper drive device or conveyor 110 configured to continuously drive the blanks 1. As shown in FIG. 3, this upper drive device 110 comprises in particular a conveyor belt 112 disposed above several conveyor rollers 114 and sufficiently spaced from the conveyor rollers 114 to allow the passage of a cutout 1 between their outer surface. Motors are provided to drive in rotation the conveyor rollers 113 (see Fig. 8b) around which the conveyor belt 112 is wound, thus allowing the translational movement of the conveyor belt 112. The combined action of the conveyor belt 112 and conveying rollers 114 thus make it possible to drive each cutout 1 in translation in direction A.

Subsequently, a conveyor 120 is arranged under the upper drive device 110. The conveyor 120 and the upper drive device 110 are configured to move the blanks 1 in the longitudinal direction A to an outlet 150 of the. folding-gluing unit 100. As in the configuration shown, this conveyor 120 may comprise an endless belt on which the blanks 1 rest. During their movement to the outlet 150, the blanks 1 are taken in charge by a device. folding 140 which is configured to fold 180 ° the left and right flaps of the cutout 1 against the central part thereof.

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SUBSTITUTE SHEET (RULE 26) This folding device 140 can in particular comprise a folding helix (not shown) formed of bars and belts provided with groups of pushing cleats and describing a curve whose torsion is proportional to the curvature, the axis of the helix coinciding with the folding axis. This folding device 140 is in particular configured to effect a folding of the blanks 1 around their longitudinal upsets 11. In order to facilitate this folding, each folding module 101 and 102 of the folding-gluing unit 100 is equipped with a liquid application arrangement 130 configured to apply liquid to one of the longitudinal upsets 11 just before the folding of the blanks 1. Thus, the arrangement 130 is advantageously positioned at the inlet of the upper drive device 110 and of the folding device 140 .

As shown in Figs. 4 to 6, the liquid application arrangement 130 comprises a housing 131 within which is housed a liquid ejection nozzle 134 supplied with liquid via a duct 171 connected at one end thereof to an orifice of the liquid. inlet 137 of the nozzle 134 and at another end to a liquid reservoir 172. The nozzle 134 has an outlet 138 through which the liquid is ejected. This orifice 138 is directed towards a guide plate 132 which is fixed to the housing 131 by means of screws. The guide plate 132 is advantageously arranged so as to be parallel to the direction of movement A of the cutouts 1 and in contact with the underside of the cutouts 1, thus allowing the guiding of the cutouts 1 during their movement. The plate 132 is further provided with an opening or a slot 133 through which can escape the liquid ejected by the nozzle 134. This slot 133 is positioned to be aligned with one of the longitudinal upsets 11 of the cutouts. 1 during their movement along the plate 132. In the example shown, the plate 132 is arranged under the cutouts 1 (see Figs. 4 and 5). However, in another possible configuration of the invention, the liquid application arrangement 130 with the plate 132 can be placed above the cutouts 1.

Furthermore, the liquid application arrangement 130 is equipped with a device in the form of an air blower 135 integral with the housing 131 and arranged so as to protrude inside a central cavity 136. of the housing 131. An air circulation channel 135b passes through the air blower 135 and is in fluid communication with a channel 135a passing through the housing 131 and opening to the outside. This channel 135a can thus be connected to a source of compressed air 173 so as to allow the projection of compressed air inside the central cavity 136 by means of the air blower 135. The channel 135b is advantageously oriented. so as to project air over the outlet port 138 of the ejection nozzle 134 and thereby allow cleaning of the outlet port.

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SUBSTITUTE SHEET (RULE 26) outlet 138 when this outlet orifice 138 is partially blocked by deposits of dust or other solid matter which prevent correct operation of the ejection nozzle 134. This cleaning step is preferably carried out when the ejection nozzle 134 is not ejecting liquid so as not to disturb the direction of the flow of liquid ejected from the ejection nozzle 134.

In the extension of the housing 131 is disposed a suction device 160 comprising an intermediate compartment 161 and a suction compartment 163 configured to generate a negative pressure inside the intermediate compartment 161. This negative pressure can be created continuously by the venturi effect generated by an accelerated air intake 174 inside the suction compartment 163. An air flow speed measurement gave a minimum value of 12 m / s at the venturi suction outlet.

The intermediate compartment 161 is fixed on the lower end of the housing 131 by means of screws cooperating with several threads 139 formed at the end. The intermediate compartment 161 is also crossed by a vertical channel 162 opening on one side into the central cavity 136 of the housing 131 and on the other side into a substantially horizontal channel 164. A tubular junction element 166 is fitted onto a free end of the channel 164. An upstream orifice 167 of the suction compartment 163 is plugged into the tubular junction element 166. Thus, the suction compartment 163 creates a negative pressure. inside the channel 164, and, consequently, inside the channel 162 and the central cavity 136. This negative pressure generates a suction flow f from the interior of the central cavity 136 towards the upstream orifice 167. This suction flow f thus makes it possible to evacuate any excess liquid ejected by the nozzle 134 which falls back inside the central cavity 136 without being absorbed by the cutouts 1. This excess of liquid sucked through the upstream orifice 167 is then discharged through a downstream orifice 168 of the suction compartment 163 towards a liquid recovery tank 175.

As shown in Fig. 5, the guide plate 132 includes an opening or a slot 133. The ejection of liquid from the nozzle can thus pass through the opening 133. Therefore, the ejection nozzle 134 and the liquid ejection opening 133 are fluidly connected. Alternatively, the same opening 133 can be used to suck up the excess liquid. To allow this, the ejection and the aspiration can be done in a discontinuous and alternating fashion. For example, the ejection of liquid is only activated when passing a cardboard blank 1. Or, alternatively the suction can

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SUBSTITUTE SHEET (RULE 26) be configured to only be activated when stopping the folding and gluing unit 100.

In another variant, the guide plate 132 comprises at least one suction opening 169, separate from the opening 133, which allows the excess liquid ejected on the cardboard blank to be sucked up 1. The suction opening 169 thus makes it possible to avoid a deposit of liquid in the folding-gluing unit 100. As illustrated, the suction device 160 comprises at least one opening 169, advantageously at least two suction openings 169 juxtaposed and arranged on each. side of the liquid ejection opening 133. It is also possible to arrange several suction openings 169, distributed around the opening 133.

Figs. 8a to 8c show the respective positions of a cardboard blank 1 in the fold-glue unit 100 shown in FIG. 3 during several successive processing steps preceding its folding.

In the position shown in FIG. 8a, the cardboard blank 1 has been introduced into the folding-gluing unit 100 at the level of the upper drive devices 110 of the first and second folding modules 101 and 102 and has moved in the direction A, in particular under the action of the conveyor belt 112, until its front edge 2 is detected by an optical detector 180 arranged directly above the guide plate 132 of the liquid application arrangement 130. In this position , one of the longitudinal upsets 11 of the cardboard blank 1, which is intended to form a fold line, is aligned with the slot 133 of the plate 132. The upsetting is further removed from the slot 133 by a distance d . This distance d is constant for the same type of cut. Depending on the speed v of advance of the blanks 1 inside the folding-gluing unit 100, a controller in charge of triggering the ejection control of the nozzle 134 programs the next ejection of liquid in a future time t, t being equal to the ratio of d to v.

In the position shown in FIG. 8b, the blank 1 has moved in the direction A from the position shown in FIG. 8a, so as to cover the aforementioned distance d. In this position, the front end of the longitudinal discharge 11 is aligned with the slot 133. The controller is about, or has just, acted on the ejection nozzle 134 so as to produce an ejection of liquid at the level. of the slot 133 and in the direction of the discharge 11.

In the position shown in FIG. 8c, the blank 1 has moved in the direction A from the position shown in FIG. 8b, so as to align the end

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SUBSTITUTE SHEET (RULE 26) rear of the longitudinal upsetting 11 with the slot IBB. The delivery 11 has therefore been subjected to the jet of liquid delivered by the ejection nozzle 134 during its entire movement from its position in FIG. 8b to its current position. The controller is about, or has just, acted on the ejection nozzle 134 so as to stop the ejection of liquid at the level of the slot 133.

Subsequently, the blank 1 will continue to move in direction A until the leading edge 2 of the new immediately subsequent cardboard blank 1 is detected by the optical detector 180. This detection will indicate to the controller that it is can trigger the next liquid ejection on this new cardboard blank 1.

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SUBSTITUTE SHEET (RULE 26)

Claims

1. Method of folding a blank (1) of corrugated cardboard intended to form a folded box (20), the method comprising the following successive steps:

i) feeding with a cutout (1) comprising at least one longitudinal upsetting (11);

ii) applying a liquid to the longitudinal upsetting (11) so as to make the corrugated cardboard more flexible at the location of the longitudinal upsetting (11), by means of a liquid application arrangement (130) comprising a liquid ejection nozzle (134) provided with a liquid outlet (138);

iii) folding the blank (1) around the longitudinal upsetting (11);

wherein a suction of liquid is carried out inside a suction compartment (163) of the liquid application arrangement (130) during step ii).

2. Method according to claim 1, wherein the suction is carried out discontinuously.

3. Method according to claim 1 or 2, wherein the excess liquid sucked in and / or the dust sucked is discharged to a liquid recovery tank (175).

4. Method according to one of the preceding claims, comprising an additional step of cleaning the liquid ejection nozzle (134) so as to remove any deposit of liquid and / or dust at least partially covering the liquid outlet. (138) of the nozzle (134).

5. The method of claim 4, wherein the cleaning step is carried out by blowing air at the liquid outlet (138).

6. The method of claim 4 or 5, wherein the cleaning is carried out discontinuously.

7. The method of claim 6, wherein the air blowing is performed by means of an air blower (135) supplied with compressed air.

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SUBSTITUTE SHEET (RULE 26)

8. Folding-gluing unit for the manufacture of folded boxes (20) of corrugated cardboard implementing the folding method according to one of the preceding claims, comprising:

at least one driving device (110) configured to drive blanks (1) of corrugated cardboard provided with at least one longitudinal upsetting (11), at least one conveyor (120) configured to move the blanks (1) of cardboard corrugated in a longitudinal direction (A) from the drive device (110),

at least one liquid application arrangement (130) configured to apply liquid to the longitudinal discharge (11), the application arrangement (130) comprising a liquid ejection nozzle (134) provided with an outlet (138), at least one suction device (160) configured to generate negative pressure within a suction compartment (163) of the liquid application arrangement (130) and configured to suck liquid,

at least one folding device (140) configured to fold the blank (1) around the longitudinal upsetting (11).

9. Unit according to claim 8, further comprising a cleaning device (135) configured to remove any deposit of liquid and / or dust at least partially covering the liquid outlet (138) of the ejection nozzle (134). ).

10. Unit according to claim 9, wherein the cleaning device comprises an air blower (135) supplied with compressed air.

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SUBSTITUTE SHEET (RULE 26)