EP0448444A1 - Folding and glueing machine for precut blanks adaptable for making boxes of different dimensions - Google Patents

Abstract

Lateral forming walls constituted by endless moving belts (11) are stretched between a roller (12) with a horizontal axis AA' disposed at the level of the horizontal conveyor bands (9) and a shaft (13) with a vertical axis BB' placed laterally at the output of the said bands, the said belts forming helically contoured channels for folding down the edges of the cardboard blanks displaced on the horizontal bands. Application to the manufacture of cardboard boxes.

Description

The invention which relates to a machine intended for forming boxes of variable size relates more precisely to a folding and gluing machine for pre-cut cardboard sheets.

To fold the tabs of pre-canned cardboard boxes, then glue them, it is known to use automatic machines which have the great advantage of cutting up the boxes formed from these boxes, at rapid rates. It goes without saying that the machine must first of all provide the parts of the carton or its edges which must be joined with glue, before folding said edges and keeping them applied together to ensure good bonding. Most machines use glue pads placed on rotating rollers which apply small areas of glue to the flat cartons which run behind one another between at least two rotating rollers. The flat cartons, pre-scalloped and pre-grooved, thus provided with glue in the appropriate places, are then directed towards a forming mandrel, which folds the edges of the carton for their automatic bonding. A forming mandrel is presented as a punch with a rectangular head, with the dimensions of the bottom of the box to be obtained, moving vertically under the action of a jack, which punch penetrating inside a box whose edges constitute the edge lifting device.

A flat box centered on this box is therefore "pushed" by the jack in the box, the edges of which simultaneously lift and glue the edges. Then the box thus formed is evacuated downwards by a conveyor belt, while the next pre-glued cardboard takes its place above the case, etc.

It must of course be that the box thus formed cannot go back up with the mandrel, so we have provided retractable locking fingers which intervene during this upward movement to release the box out of the mandrel.

These known machines are advantageously used for the mass production of boxes of same template. But they very quickly become unusable for small or medium series, insofar as any dimensional modification of the base carton, or of the dimensions of the box to be folded and glued, requires the change of the mandrel, and new presets and tests of the machine, all operations which are long and costly. The problem already arises quite simply when it comes to making a series of lids for a series of formed boxes. It is indeed necessary to change the mandrel, since the bottom will be very slightly smaller than that of the cover and to modify the depth since the edges of a cover are generally less tall than those of the bottom of the corresponding box. It will also be necessary to move and / or modify the bonding pads of the corresponding roller. All these adjustment and replacement operations are carried out by disassembly and reassembly, manually, using appropriate keys; under these conditions, it is understood that for limited series, the loss of time caused by these adjustments largely compensates for the advantages inherent in the production rate.

Apart from these structural drawbacks, it has appeared that the distribution of glue by application from rollers is extremely delicate, either because of the excess of product which causes sagging or stains, or because of the lack of product which causes detachment. of the box.

The improvements envisaged on existing machines, not being able to sufficiently improve their flexibility of use, the Applicant has imagined a machine of entirely different design which avoids the abovementioned drawbacks, and moreover is simpler to produce.

The main object of the invention therefore consists of a folding and gluing machine for pre-cut boxes, adaptable to the manufacture of boxes of different dimensions, comprising a distribution zone piece by piece of boxes stacked flat on at least one conveyor belt which routes them to a forming mechanism intended to fold and glue the tabs of said cardboard, and of the bodies for evacuating the formed boxes, machine in which the forming mechanism consists essentially of two lateral forming walls framing the horizontal conveyor belt and forming gutters profiled in a helix from from a horizontal plane at the entrance to the forming zone to a vertical plane at the exit from this zone, and according to which it comprises, after said forming mechanism, a gluing zone comprising a gluing mechanism and at least one cylinder movable from bottom to top to fold the front and rear edges of the carton.

According to another particular characteristic of the invention, the lateral forming walls consist of several endless moving belts stretched between a roller with a horizontal axis disposed at the level of the horizontal conveyor belts and at the entrance to the forming zone and a vertical axis shaft placed at the outlet of said zone laterally to the conveyor belts.

More specifically, at least one belt returns to the roller and the shaft as close as possible to the conveyor belts, while at least one other belt returns to the roller and the shaft as far as possible from said belts.

The machine according to the invention also has, in the gluing area, glue dispensing nozzles, oriented horizontally in the direction of the central strips and supplied from a programmed central glue production unit.

In addition, in the gluing zone are provided, on either side of the central strips, pressure cylinders acting transversely towards the center of the machine, and at the exit from the gluing zone are provided cylinders the profiled head movable from the bottom up can act on the edges of a cardboard.

• Figure 1 une vue générale schématique en perspective de la machine plieuse et colleuse ;
• Figure 2 une vue partielle en perspective d'un mécanisme de formage à courroies sans fin ;
• Figure 3 une représentation en perspective d'une forme particulière de réalisation de la zone de distribution et de la zone de formage de la machine ;
• Figure 4 et 5 des vues schématiques en élévation et de dessus des différents éléments de la machine ;
• Figure 6 une vue en élévation d'une autre représentation schématique de la machine et figure 7 une vue en plan des quatre phases I à IV de préparation d'un carton correspondant aux zones de fabrication de la machine.

Other particular characteristics and advantages of the invention will appear on reading the following description of embodiments taken from title of examples and referring to the attached drawings which represent:

• Figure 1 a general schematic perspective view of the folding and gluing machine;
• Figure 2 a partial perspective view of an endless belt forming mechanism;
• Figure 3 a perspective representation of a particular embodiment of the dispensing area and the forming area of the machine;
• Figure 4 and 5 schematic elevational views from above of the various elements of the machine;
• Figure 6 an elevational view of another schematic representation of the machine and Figure 7 a plan view of the four phases I to IV of preparing a carton corresponding to the manufacturing areas of the machine.

The machine shown as a whole in FIG. 1 consists of a frame 1 extending longitudinally, which can be divided into four zones: a distribution zone (A), a forming zone (B), a zone glue (C) and an evacuation zone (D).

Zone (A) essentially comprises a feed belt 5 formed of a plurality of conveyor belts 2 receiving a stack of cartons 3 guided between two lateral guide edges 4. A bracket 6 overhanging the belt 5, carries a profiled blade 7 for retaining cartons in offset stack, blade through which the cartons are distributed piece after piece one after the other in the direction of the next station, in the direction of the arrow. A retractable stopper 8 is provided to allow only one cut to be engaged at a time.

The forming zone (B) has a forming mechanism which can be called the "former" and essentially comprises a set of horizontal conveyor belts 9 extending the belts 2 and two lateral forming walls 10, framing the bands 9 and in a way constituting gutter profiles in helix, of width 1 which, at the level of the beginning of the strips 9, are in a plane horizontal, then gradually straighten in twist until the exit of this zone where the two walls 10 are then in a vertical plane. These walls may, according to a variant embodiment not shown, consist of independent semi-rigid rods juxtaposed and more or less spaced from each other, rods which together form a helical sheet as before.

According to another advantageous alternative embodiment illustrated in FIG. 2, the lateral forming walls consist of several endless moving belts 11.

For the sake of clarity, only three have been shown, on one side of the horizontal conveyor belts 9. Each of these belts 11 is stretched between a roller 12 with a horizontal axis AA ′ disposed at the level of the distribution belt 2 and bands 9, at the entrance to the forming zone and a shaft 13 of vertical axis BB ′ placed at the exit from the forming zone, laterally to the conveyor belts 9. It can be seen that the belt 11a runs approximately along the horizontal conveyor belt since it returns to the roller 12 as close as possible to said belt and to the shaft 13 at the bottom thereof. Conversely, the belt 11c starts from a location on the roller 12 as well as on the shaft 13 which is furthest, laterally and in height, from the conveyor belt. The belt 11b occupies an intermediate position. So that the belts do not shift on their support, they are guided in profiled rollers 14 forming sleeves around the roller and the shaft, to which they can be fixed to follow their rotational movement. At least two side rollers 14a and 14c, both on the roller 12 and on the shaft 13 can be moved on their support, that is to say more or less apart or closer together to modify the location and spacing of the belts 11 depending on the width of the carton to be folded. Once in position the rollers 14 are easily fixed to their support by keying or other system similar.

FIG. 3 shows a general schematic representation of a particular embodiment showing the distribution zone (A), the forming (B) and gluing (C) zone, in which continuous central strips 15 replace the carpet d feed 5 and the conveyor belts 9. These belts mesh on a drive roller 16 driven by a motor 17. The same motor by means of the transmission chains 18 drives the two horizontal rollers 12 and consequently the belts 11, which rotate in synchronism with the bands 15.

Referring also to FIGS. 4 and 5 in which the forming walls consist of belts 11, it can be seen that the central strips 15 extend a little beyond the vertical shaft 13.

In this gluing zone (C) there are provided nozzles 19 for dispensing glue oriented horizontally in the direction of the central strips and supplied by conduits 20 from a programmed central unit 21 for producing glue (FIG. 1). Near the nozzles are provided, on either side of the central strips, two press jacks 22 acting transversely towards the center of the machine.

At the exit from the gluing zone (C) are provided jacks 23, whose profiled head 24, movable from bottom to top can act on the edges of a carton.

In the gluing zone (C) the evacuation takes place by a horizontal transfer mat 25 mounted on rollers 26, which is bordered laterally by a plurality of endless belts 27 returning on vertical rotating axes 28. A the output of this mat, there is a set of cylinders 29 similar to the cylinders 23 disposed at the entrance. Beyond this transfer belt 25, extends a recovery plate 30 located in the evacuation zone (D), possibly also consisting of a movable belt, which develops between guide edges 31. A jack pressing 32 acting vertically from top to bottom, frames two lateral jacks 33 acting in the direction of the center, all of the jacks being located at the entrance to said recovery plate 30.

The operation of the machine will now be described with reference to FIGS. 6 and 7 which show the development of a carton with respect to the different zones of the machine.

At the distribution zone (A), a cardboard box 3, received by the supply conveyor 5 is placed so that its notches 34 are oriented transversely to the direction of unwinding of the conveyor. The cardboard 3 is therefore flat, including its lateral edges 3a, its front edge 3b and its rear edge 3c.

Grooves 35 mark the cardboard - in view of its folding - between the central part 3 and its peripheral edges. Other small grooves 36 delimit on the front and rear edges, at the notches 34, small tabs or tabs 37. The marking of the longitudinal grooves 35, that is to say grooves located between the bottom 3 and the lateral edges 3a can easily be provided continuously on a succession of cardboard and by the same pass, on another machine for preparing grooved cardboard. As against the transverse grooves 35, between the bottom 3 and the front edges 3b and rear 3c are, it is understood, less easy to achieve than the previous ones, and require a total recovery of the boxes and a new grooving station.

The machine according to the invention has the advantage of being able to use cartons which would not have these transverse grooves, since the jacks 24, 29 ensuring the folding of the front and rear edges, would ensure this work correctly, even in the absence of this transverse pre-cleaning. The machine therefore saves time upstream during the preparation of cartons.

The cardboard (position I) is therefore released from the distribution zone (A) by the stopper 8 and will be taken up in the forming zone (B) by the strips 9. The edges sides 3a of the carton 3 then come to bear against the lateral forming walls 10. In the case of the embodiment according to FIG. 2 where the walls in question consist of endless bands 11, the lateral edges 3a of the carton engage between two neighboring bands 11a, 11b closest to the bands 9.

In all cases, the cardboard being driven by the bands 9 causes the lateral edges 3a to be folded upwards according to the corresponding grooves 35 as well as the tongues 37 to be folded relative to the front and rear edges according to the grooves 36. At the leaving this folding zone, the cardboard 3 therefore has its folded lateral edges as seen in position II in FIG. 7. At the end of the forming zone B, this partially folded cardboard will overflow forward. The latter stop for a short time when the front edge 3b has escaped from said strips. Or when, in the case of FIG. 4, the cardboard has reached the limit of the projecting part of the strips 15. At this time the nozzles 19 apply a few lines of glue to the outer wall of the small folded tabs 37. Immediately afterwards, the jack 23 comes into action so that the head 24, by its vertical movement from bottom to top folds said front edge towards the inside of the carton, front tabs 37 therefore being folded along the inner flank of the side edges 3a already folded. These front tabs provided with their glue lines, are therefore glued against the lateral edges 3a of the carton. A pressure mechanism, not shown, with timed action can promote the bonding action. It will be noted that the fact of applying glue horizontally to the cutting tabs or tabs by means of the nozzles has an advantageous advantage, because when the tongues have tilted under the action of a jack the lines of glue are are oriented vertically and strengthen their bonding to the folded side of the cardboard.

The cardboard in position III then leaves the start of the gluing area (C). It is then taken up by the carpet horizontal transfer 25 and moved, guided by the belts 27 until its rear tabs 37 are in front of the nozzles 19 where they can receive their dose of glue, this operation being done during a very short stop of the carton or during its continuous movement on the mat 25. Then the cardboard reaches the plate 30 on which it stops when its rear edge 3a is at the level of the jacks 29. These act like the jacks 23 and fold the rear edge 3c whose tabs come to bonding, similar to those of the front edge, against the inner flank of the side edges 3a. The pressing cylinders 32 and 33 operate on the front and rear edges to perfect the bonding of the finished cardboard (position IV in figure 7).

All of the mechanisms, whether at the forming, gluing or evacuation area, can be easily adjusted in width or height to adapt to any size of cardboard to be produced. Thus, when we want to move to the realization of a series of cartons of larger dimension than the current series, it is first necessary to move aside the lateral forming walls 10, or the set of endless belts 11 which constitute the former. . These walls are mounted on mobile supports which can be moved away from one another by the operation, for example, of a single rod with double thread, with manual or motorized rotation. In the same way, the gluing machines, the lateral jacks, the lateral guiding edges, etc ... move apart in the same way to adapt to the new size of the boxes. This adjustment of adjustment is advantageously carried out in a programmable manner on the keyboard, making it possible to eliminate long and imprecise manual adjustments.

Apart from the possibility of making, with this machine, boxes of small or large lengths or widths, it is possible to use, and this is an important advantage, - different thicknesses and materials, for example compact cardboard or corrugated cardboard with fine grooves or larger grooves. make very long cartons, since the folding and gluing of a front edge can be carried out while the back of the carton is still in distribution area A, and even further forward. This kind of exceptional achievement is quite impossible with a conventional machine.

Finally, thanks to this machine with height-adjustable feet, a work station is defined which makes the command, control and adjustment organs easily accessible to the user.

Claims (11)

1.- Folding and gluing machine for pre-cut boxes, adaptable to the manufacture of boxes of different dimensions, comprising a piece-by-piece distribution zone of boxes stacked flat on at least one conveyor belt which routes them to a forming mechanism intended for fold and glue the edges of said carton, and of the evacuation members of the formed boxes characterized in that the forming mechanism essentially consists of two lateral forming walls (10, 11) framing the horizontal conveyor belt (9) and forming gutters profiled in a helix from a horizontal plane at the entrance to the forming zone (B) to a vertical plane at the exit from this zone, and in that it comprises, after said forming mechanism, a gluing area (C) comprising a gluing mechanism (19, 21) and at least one cylinder (23, 24) movable from bottom to top to fold down the front and rear edges of the carton. 2. Machine according to claim 1, using on either side of the horizontal conveyor belt, a lateral forming wall consisting of an endless moving belt, characterized in that the lateral forming wall consists of several belts endless mobiles (11) which are stretched between the same roller (12) with a horizontal axis AA ′ disposed at the level of the horizontal conveyor belts (9) and at the entrance to the forming zone (B) and one or the other of two trees (13) with a vertical axis BB ′ placed at the outlet of said zone laterally to the conveyor belts. 3.- Machine according to claims 1 and 2 characterized in that at least one belt (11a) returns to the roller (12) and the shaft (13) closest to the horizontal conveyor belts (9), while at least one other belt (11c) returns to the roller and the shaft farthest from said strips (9). 4.- Machine according to claims 2 and 3 characterized in that the belts (11) are guided in profiled rollers (14) forming sleeves around the roller and the shaft, at least two side rollers which can be moved apart or brought together from each other, both on the roller (12) and on the shaft (13). 5.- Machine according to claims 1 and 2, characterized in that continuous central strips (15) extend from the distribution area (A) to the forming area (B) and gluing area (C) and mesh on a roller (16) which also rotates the horizontal rollers (12) of the endless moving belts (11). 6.- Machine according to claims 1 and 2, characterized in that in the gluing zone (C) are provided nozzles (19) for dispensing glue, oriented horizontally towards the central strips and supplied from a programmed central unit (21) for glue production. 7.- Machine according to claim 6, characterized in that the nozzles apply horizontal lines of glue on folding tabs (37) of a carton, so that the lines of glue are vertical after folding of said tabs, at the time of bonding . 8.- Machine according to claims 1 and 2, characterized in that in the gluing zone (C) are provided, on either side of the central strips, press jacks (22) acting transversely towards the center of the machine. 9.- Machine according to claims 1 and 2, characterized in that at the outlet of the gluing zone (C) are provided jacks (23) whose profiled head (24), movable from bottom to top can act on the edges of a carton. 10.- Machine according to claims 1 and 2 characterized in that at the entrance to an evacuation zone (D) following the gluing zone (C) are provided other cylinders (29) movable from bottom to top to act also on the edges of a carton 11.- Machine according to claim 10 characterized in that the evacuation zone (D) comprises a transfer mat (25) followed by a plate (30) for recovery, pressing cylinders (32,33) being provided respectively above and laterally to this transfer mat.

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