EP0472981B1 - Method and machine for erecting a foldable box - Google Patents

Abstract

Method for erecting a foldable box from a one-part cardboard blank which has a bottom surface, side walls articulated on this via folding lines and a front wall and rear wall, there being formed on the side wall flaps which are folded into the region of the front and rear walls, and which is coated at least partially with a sealable plastic. At the same time, the two side walls are first erected in that the cardboard blank is pressed into a U-shaped bottom mould (4). The flaps are folded in by means of rotating drivers (30); the rear wall and front wall are heated until the plastic coating becomes sealable, whereupon the rear wall and front wall and the flaps are pressed against one another and sealed together. <IMAGE>

Description

The invention relates to a method and a machine for erecting a folding box from a one-piece cardboard blank, which has a bottom surface, side walls articulated thereon via folding lines and a front and a rear wall, flaps being formed on the side walls, which flaps are formed in the region of the front and the rear wall are folded and which is at least partially coated with a sealable plastic, the two side walls first being erected by pressing the cardboard blank into a U-shaped lower mold by means of a stamp, whereupon the flaps are folded in.

Such folding boxes should be erected quickly because they are used in large numbers. At the same time, however, a high quality of the erection process is required in order to obtain dimensionally accurate folding boxes.

Such a method for erecting a folding box is known from US-A-1 978 057, but it is extremely complicated. After raising the two Side walls are first folded over two dust flaps and glued together. Then the two-part front wall and rear wall are folded around these dust flaps and glued to both sides of the dust flaps. Folding the two dust flaps on one side of the box in and out is very complex. The front and rear walls can only be folded up and back after the stamp has been removed; however, due to the lack of internal support, a mutual sealing cannot be carried out.

The invention has for its object to show a method and a machine with which the erection can be carried out with very high precision and at the same time very easily and quickly.

This object is achieved in that the rear wall and the front wall are heated to such an extent that the plastic coating becomes sealable, whereupon the rear wall and the front wall as well as the flaps are pressed against the form stamp and thus against one another and sealed to one another, with the rotating drivers being the Flaps are pressed against the front wall and the rear wall or the two walls against the flaps.

With this process, an exactly and always consistently erected folding box is produced in an extremely efficient manner.

A machine according to the invention for erecting a folding box from a one-piece cardboard blank, which has a bottom surface, side walls articulated thereon via folding lines and a front and a rear wall, between which and the side walls dust flaps are provided and which is at least partially coated with a sealable plastic, wherein a U-shaped lower mold attached to a transport chain is provided is, which has a base plate and a front and rear leg, with this lower mold is assigned a stamp attached to another chain, is characterized in that on both sides of these transport chains are provided with a recess provided locking wheels that serve to fold in the dust flaps that the two closing wheels are provided with a circumferential groove, which preferably extends to the bottom of the recess and in which retaining rails for the folded-in dust flaps are able to engage, which connect to the closing wheels, that a hot air nozzle is provided on both sides following the closing wheels, whose outlet openings are directed against the inside of the front and the rear wall, and that pressure rails are provided behind the hot air nozzles for placing the front and rear walls on the dust flaps and pressing them against one another.

This machine allows a folding box to be erected in a functionally correct manner, and in addition to a very high precision of the folding box, a very high working speed can be achieved.

Another machine according to the invention for erecting a folding box from a one-piece cardboard blank, which has a bottom surface, side walls articulated thereon via folding lines and a front and a rear wall, flaps being formed on the two side walls, which also form gussets with the other two Walls are connected, with a U-shaped lower mold fastened to a transport chain, which has a base plate and a front and rear leg each, which is assigned a form stamp fastened to a further chain, is characterized in that rails for folding in the transport chains on both sides Front and rear walls are provided, to which are connected closing wheels provided with a recess, which serve to fold in the flaps, that the two closing wheels are provided with a circumferential groove, which preferably extends to the bottom of the recess and in which holding rails are able to engage, with hot air nozzles being provided directly in front of the locking wheels, which are used to heat the outside of the front or rear wall and the gusset and flaps, and that pressure rails for pressing the flaps with the gussets and the front and rear walls are arranged after the locking wheels.

With this machine it is possible to produce tight folding box lower parts with high precision and at high speed.

It is also very advantageous if, according to the invention, the pressure rails are provided with cutouts in which pressure rollers mounted in a spring-elastic manner are arranged.

As a result, not only is the pressure applied very gently on the material, but the contact pressure is also easily adjustable.

It has proven to be very favorable if, according to the invention, levers are pivotally mounted on the underside of the pressure rails, on which springs act and which carry the pressure rollers.

It has also proven to be very advantageous if, according to the invention, the form stamp is guided in a rail, which forcibly adjusts the distance of the form stamp from the base plate of the lower mold.

Fig.1

eine schematisierte Seitenansicht einer Maschine zum Aufrichten einer Faltschachtel mit zwei Transportketten für einen Formstempel und einer U-förmigen Unterform sowie mit zwei Schließrädern,

Fig.2

eine Draufsicht auf die Maschine nach Fig.1 mit sichtbarer Rollenstrecke,

Fig.3

eine schematisierte Seitenansicht einer weiteren Maschine zum Aufrichten einer dichten Faltschachtel,

Fig.4

eine Ansicht eines Kartonzuschnittes aus dem die Faltschachtel mit der Maschine gemäß Fig.1 u. 2 aufgerichtet werden soll,

Fig.5

eine Ansicht eines Kartonzuschnittes zum Herstellen eines dichten Unterteils einer Faltschachtel mit der Maschine gemäß Fig.3

Fig.6

ein aus dem Zuschnitt nach Fig.5 aufgerichtetes Faltschachtel-Unterteil und

Fig.7 u.8

vergrößert dargestellte Details der Rollenstrecke.

This configuration makes it possible to dispense with further control elements for the form stamp.
The invention is illustrated in the drawing using several exemplary embodiments. Show:

Fig. 1

2 shows a schematic side view of a machine for erecting a folding box with two transport chains for a form stamp and a U-shaped lower mold and with two closing wheels,

Fig. 2

1 shows a plan view of the machine according to FIG. 1 with a visible roller path,

Fig. 3

a schematic side view of another machine for erecting a tight folding box,

Fig. 4

a view of a cardboard blank from which the folding box with the machine according to Fig.1 u. 2 to be erected,

Fig. 5

a view of a cardboard blank for producing a tight lower part of a folding box with the machine according to Figure 3

Fig. 6

a folding box bottom part erected from the blank according to FIG. 5 and

Fig. 7 and 8

Details of the roller track shown enlarged.

1 with a machine for erecting a folding box is referred to, which has two transport chains 2 and 3. On the lower transport chain 2, a plurality of U-shaped lower molds 4 are attached, with this Run around the transport chain and each have a base plate 5 and a front and rear leg 6.7. Each of these U-shaped lower molds 4 is assigned a die 8 which is attached to the upper transport chain 3 and rotates with it. A guide rail is provided within the upper transport chain 3, which forcibly guides the molding die in its vertical position and brings it into engagement with the U-shaped lower mold.

A cardboard blank 10 as shown in FIG. 4 is inserted between the lower mold 4 and the die 8. This cardboard blank has a bottom 11, on each of which a side wall 14 or 15 is articulated via fold lines 12 and 13. Each of these two side walls 14, 15 laterally carries a dust flap 16, 17 and 18, 19, respectively, which are hinged to the two side walls via folding lines 20 and 21. A front wall 23 and a rear wall 24 are also articulated on the floor 11 via these folding lines 20, 21. The rear wall 24 carries, via a further folding line 25, a cover flap 26 which has side wall flaps 27, 28 and a front wall flap 29 which cover the two side walls 14, 15 and the front wall 23 in the fully erected state of the folding box.

To the side of the lower transport chain 2 there are two locking wheels 30 which rotate in opposite directions and are provided with a circumferential recess 32. In addition, the two closing wheels are each equipped with a circumferential groove 33, in which a subsequent folding strip 34 engages with one end. A hot air nozzle 35 is arranged laterally next to this folding strip 34 and has its outlet openings 36 on the side facing away from the folding strip 34. On the side of the hot air nozzle 35 facing away from this folding strip 34, a further folding strip 37 is arranged, which extends from below the closing wheels 30 to at least the height of the first folding strip 34 and is detached from a pressure rail 38.

As can be seen from FIG. 2, not only the closing wheels 30 but also the folding strips 34 and 37, the hot air nozzles 35 and the pressure rails 38 are arranged on both sides of the transport chains 2 and 3.

The pressure rail 38 is provided with rotatably mounted pressure rollers 39, which are embedded in corresponding cutouts 40 in the pressure rail and are seated on levers 41 mounted on the underside of the rail. Invisible springs attack the levers, which press them and thus the rollers outwards.

When the die is lowered, it presses the bottom 11 of the cardboard blank 10 according to FIG. 4 into the U-shaped lower mold 4, the two side walls 14 and 15 standing up laterally and being clamped between the two legs 6, 7 and the die. The dust flaps 16, 17, 18, 19 protrude laterally from the lower mold 4. As soon as the lower mold reaches the closing wheels 30, the two front dust flaps 17 and 19 are placed by the latter on the die 8 and held in this position by the folding strips 34. The two rear dust flaps 16 and 18 get into the recess 32 of the two locking wheels 30 and are also applied to the form stamp by their rotational movement and then held in this position by the folding strips 34. The folding strips 37 raise the front wall 23 and the rear wall 24 somewhat, so that the hot air coming from the hot air nozzles 35 or their outlet nozzles 36 reaches the inner surface of these two walls coated with sealable plastic. In the further course, the two folding strips 37 press these two walls up until they come into contact with the dust flaps, the actual pressing process being carried out by the subsequent pressure rails 38 or their pressure rollers 39, which directly adjoin the folding strips 37. Due to the resilient pressure of this Pressure rolls can also compensate for slight differences in material thickness.

The machine 50 according to FIG. 3 largely corresponds to the machine 1 described above, only the hot air nozzles 35 are arranged in front of the closing wheels 30 and in front of the hot air nozzles there are still rails 51 on both sides of the transport chains 2, 3 for folding the front and rear walls of the in 5 shown blank 61 or the folding box lower part 80 erected therefrom (FIG. 6).
The flat cardboard blank 61 shown in FIG. 5 has a bottom section 62, to which a side wall section 65 and 66 is articulated via fold lines 63 and 64. In addition, two end wall sections 67 and 68 are integrally formed on the bottom section, which are also connected to the side wall sections 65 and 66 via fold lines 63 and 64. Two further fold lines 69, 70 and 71, 72 each start from the two fold lines 63 and 64, through which gusset corners 73, 74, 75, 76 are divided between the side wall sections and the end wall sections. These gusset corners 73 to 76 and the section of the respective end wall section 67 or 68 divided off by the line 77 or 78 is provided on the outside and the inside with a sealable plastic layer, which is shown in FIG. 5 by hatching. To erect this cardboard blank 61 into the cup-shaped shell 80 shown in FIG. 6, the two side wall sections 65 and 66 are first folded upward about the fold lines 63 and 64 by being pressed into the U-shaped lower mold; then the two end wall sections 67 and 68 are bent upwards by the folding rail 51. After heating by the healing air nozzles 35, the gusset corners and the end sections of the side wall sections are then unfolded by the closing wheels 30, whereupon all three layers are pressed together and sealed by the pressure rails 38.

Claims (6)

1. Process for erecting a folding carton from a single-piece board blank which has a base surface, to which side panels are hinged along folding lines, and a front and back panel, where flaps are provided on the side panels that are folded into the area of the front and back panels, and at least sections of which are coated with a sealable plastic, where first of all the two side panels are erected by pressing the board blank into a U-shaped female tool with a male tool, after which the flaps are folded into position, wherein the back and front panels are heated up to such an extent that the plastic coating is sealable, after which the back panel and the front panel and the flaps are pressed against the male tool and thus against each other and are sealed together, rotating lugs pressing the flaps against the front panel and the back panel or the two panels against the flaps.
2. Machine to erect a folding carton from a single-piece board blank which has a base surface, to which side panels are hinged along folding lines, and a front and back panel, between which and the side panels dust flaps are provided, and which is coated with sealable plastic at least in places, to carry out the process according to claim 1, where a U-shaped female tool (4) attached to a transport chain (2) is provided, which has a base plate (5) and a front and back section (6, 7), and where this female tool (4) has a male tool (8) allocated to it that is attached to another chain (3), wherein closing wheels (30) with a recess (32) at one point are provided on both sides of these transport chains to fold in the dust flaps (16, 17, 18, 19), wherein both closing wheels (30) have a groove (33) around their circumference that preferably goes down to the bottom of the recess (32) and that holding bars (34) for the folded-in dust flaps that follow the closing wheels can engage, wherein a hot air nozzle (35) the openings (36) of which are directed towards the inside of the front and the back panel (23, 24) is provided on both sides following the closing wheels (30) and wherein pressure bars (38) to position and mutually press the front and back panels against the dust flaps are provided after the hot air nozzles (35).
3. Machine to erect a folding carton from a single-piece board blank which has a base surface, to which side panels are hinged along folding lines, and a front and back panel, where flaps that are also connected to the other two panels forming gussets are provided on the two side panels, to carry out the process according to claim 1, with a U-shaped female tool (4) attached to a transport chain (2), which has a base plate (5) and a front and back section (6, 7), and to which a male tool (8) is allocated that is attached to another chain (3), wherein bars (51) for folding in the front and back panel are provided on both sides of these transport chains (2, 3) and are followed by closing wheels (30) with a recess (32) at one point that serve to fold in the flaps, wherein the two closing wheels (30) have a groove (33) around their circumference that preferably goes down to the bottom of the recess (32) and that holding bars (34) can engage, while hot air nozzles (35) for heating up the outside of the front and back panel, the gussets and the flaps are provided directly before the closing wheels and wherein pressure bars (38) for pressing the flaps against the gussets and the front and back panels are located after the closing wheels (30).
4. Machine according to claim 2 or 3, wherein the pressure bars (38) have recesses (40) in which spring-loaded pressure rollers (39) are located.
5. Machine according to one of the previous claims, wherein levers (41) are pivoted on the underneath of the pressure bars (38), which springs engage and which support the pressure rollers (39).
6. Machine according to one of the previous claims, wherein the male tool (8) is guided in a rail which automatically sets the distance between the male tool and the base plate (5) of the female tool (4).

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