System and method for forming boxes from cardboard blanks

Abstract

A system for automatically forming packaging boxes comprises a folding station comprising four folding units adapted to fold panels of cardboards blanks to form substantially cuboid boxes or lids or combinations of a box and a lid, some of said panels in the folded state forming pairs of two panels running substantially parallel to each other in a processing direction, in which the blanks are transported through the system, and orthogonal to a width direction of the blanks, which is the orthogonal direction to the processing direction in the plane of the blanks, one or more glue application units adapted to put glue on at least one panel of each of said pairs of two panels, a feeding conveyor to convey a cardboard blank into the folding station, a curing station adapted to take over the boxes or lids or combinations of a box and a lid folded in the forming station from the folding station, said curing station comprising holding structure to form-fittingly hold said pairs of panels and to guide the boxes or lids or combinations of a box and a lid through the curing station.

Claims

1. A system for automatically forming packaging boxes, the system comprising: a folding station comprising four folding units to fold panels of cardboard blanks to form substantially cuboid boxes or lids or combinations of a box and a lid, some of said panels in the folded state forming pairs of two panels running substantially parallel to each other in a processing direction, in which the cardboard blanks are transported through the system, and orthogonal to a width direction of the cardboard blanks, which is the orthogonal direction to the processing direction in the plane of the cardboard blanks, one or more glue application units to put glue on at least one panel of each of said pairs of two panels, a feeding conveyor for conveying ones of the cardboard blanks into the folding station, a curing station adapted to take over the boxes or lids or combinations of a box and a lid folded in the folding station from the folding station, said curing station comprising a holding structure to form-fittingly hold said pairs of panels and to guide the boxes or lids or combinations of a box and a lid through the curing station, said holding structure comprising a first side guiding element and a second side guiding element substantially parallel to the first side guiding element, a distance of the first and second side guiding elements and a distance of the folding units in said width direction being adjustable to different widths of boxes or lids or combinations of a box and a lid to be folded in the folding station, and wherein said first and second side guiding elements are extendable in their length seen in the processing direction.

2. The system of claim 1, wherein the folding units are arranged to form a pair of rear folding units and a pair of front folding units, the pair of rear folding units being arranged in the processing direction closer to the feeding conveyor than the front folding units, said pairs of folding units being movable relative to each other.

3. The system of claim 1, said holding structure and at least one of said pairs of folding units being movable relative to each other.

4. The system of claim 1, wherein said first and second side guiding elements are formed by panels or arrangements of rods.

5. The system of claim 1, further comprising a transport device operable to transport the box into and/or through the curing station.

6. The system of claim 1, wherein said at least one glue application unit applies portions of hot melt glue with at least two different surface-to-volume ratios.

7. A method for automatically forming packaging boxes comprising: folding the panels of cardboard blanks to form substantially cuboid boxes or lids or combinations of a box and a lid, some of said panels in the folded state forming pairs of two panels running substantially parallel to each other in a processing direction in which the blanks are transported, and orthogonal to a width direction of the blanks, which is the orthogonal direction to the processing direction in the plane of the blanks, wherein the folding is done in a folding station comprising four folding units arranged to form a pair of rear folding units and a pair of front folding units, the pair of rear folding units being arranged in the processing direction closer to a feeding conveyor, which feeds cardboard blanks to said folding station, than the front folding units, the method further comprising moving at least one of said pairs of folding units towards the curing station for transporting the folded boxes or lids or combinations of a box and a lid into the curing station; prior to folding the panels forming said pairs into a position, in which both panels of a pair run substantially parallel to each other, applying glue on at least one panel of each of said pairs of two panels, transporting the folded boxes or lids or combinations of a box and a lid while form-fittingly holding said pairs of panels into a curing station comprising a holding structure to form-fittingly hold said pairs of panels and for guiding the boxes or lids or combinations of a box and a lid through the curing station, form-fittingly holding said pairs of panels in the curing station allowing the glue to cure and guiding the boxes or lids or combinations of a box and a lid through the curing station, and extending said guiding elements in their length seen in the processing direction.

8. The method of claim 7, comprising moving said holding structure and said folding station relative to each other.

9. The method of claim 7, said holding structure comprising a first side guiding element and a second side guiding element substantially parallel to the first side guiding element, the method further comprising adjusting the distance of the side guiding elements and the distance of the folding units in said width direction to different widths of boxes or lids or combinations of a box and a lid to be folded in the folding station.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a perspective view of a cardboard blank for folding an open box.

(2) FIG. 2 is a perspective view of a box folded from the blank shown in FIG. 1.

(3) FIG. 3 shows some parts of a folding station for folding cardboard blanks.

(4) FIG. 4 shows a folding unit of a folding station according to FIG. 3.

(5) FIGS. 5 to 10 show very schematically different stages during operation of a system according to the invention.

(6) FIG. 11 shows parts of a system for automatically packaging varying shipment sets in custom-sized cardboard boxes.

(7) FIG. 12 shows parts of a curing station according to one embodiment of the invention.

(8) FIG. 13 shows parts of a curing station according to one embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

(9) FIG. 1 shows a blank 10 fora type 0300 box, having a bottom panel 12, a first end panel 14, a second end panel 16, a first side panel 18, a second side panel 20, two first corner panels 22 and 24 joined to opposite edges of the first end panel 14 and two second corner panels 26 and 28 joined to opposite edges of the second end panel 16. The panels are delimited against each other via eight crease lines 30-44 respectively four slots 46, 48, 50 and 52. The crease lines 38 and 44 are with respect to the crease line 36 slightly shifted, namely to an amount corresponding to the thickness of the cardboard towards the first end panel 14 respectively the second end panel 16. Likewise, the crease lines 40 and 42 are shifted in an amount corresponding to the thickness of the cardboard towards the first end panel 14 respectively towards the second end panel 16 with respect to the crease line 48. Thus, the width W.sub.EP of the end panels 14 and 16 is slightly less than the width W.sub.BP of the bottom panel 12. This allows that in the erected state as shown in FIG. 2, the corner panels 22 and 28 run perfectly parallel to the side panel 18 and the corner panels 24 and 26 run parallel to the side panel 20.

(10) Shifting the crease lines 38 and 44 with respect to the crease line 36, and shifting the crease lines 40 and 42 with respect to the crease line 32 also leads to the fact that the length L.sub.CP of the corner panels is to the amount of shifting greater than the height H.sub.SP of the side panels.

(11) The slots 46, 48, 50 and 52 are also dimensioned to take into account the thickness of the cardboard: the height H.sub.CP of the corner panels has to be decreased by the thickness of the cardboard as in the erected state these corner panels abut against the bottom panel while the top side of the corner panels shall, in this type of box, be level with the top end of the end panels. The height H.sub.EP of the end panels 14 and 16 corresponds to the height H.sub.SP of the side panels 18, 20, which in this type of box defines the maximum height of the box. However, the invention is not limited to this type of boxes, but can for example also be used with boxes such as the ones disclosed in WO 2019 081773 A1 or other types.

(12) Due to the material inherent properties, the slots are typically not made such that only the height Hop of the cornel panels is shortened, but also the length L.sub.SP of the side panels, which facilitates erecting the box and ensures that the side panels do not extend beyond the end panels in the erected state. Hence, the length L.sub.SP of the side panels 18, 20 is typically a bit shorter than the length L.sub.BP of the bottom panel 12. As stated above, the first end panel 14 is considered here to be the front end panel, that is the panel that forms the front of the blank in the processing direction, in which it is transported through the system for creating boxes, whereas the second end panel 16 forms the rear end in that direction and is accordingly called rear end panel. Likewise, the first corner panels 22 and 24 are called front corner panels, whereas the second corner panels 26 and 28 are called rear corner panels.

(13) FIG. 3 shows schematically some parts of a folding station 60 according to the prior art for folding cardboard blanks like the blank 10 shown as one example in FIG. 3 to form packaging boxes. The blank 10 has a slightly different layout than the blank shown in FIGS. 1 and 2 (the height of the end panels 14 and 16 is greater than the height of the side panels 18 and 20), but both and other layouts may equally be treated according to the invention.

(14) The folding station 60 shown comprises four folding units, each comprising a corner panel folding element 62, of which in the shown situation, in which a cardboard blank 10 has been placed on the folding station and the corner panel folding elements 62 have started to push the corner panels 22, 24, 26 and 28 upwards, only two are visible.

(15) The folding units are slidably mounted on rods 64, 66 and 68 in order to be moveable in a plane parallel to the plane of the cardboard blank 10, as the cardboard blanks to be folded may in this embodiment differ in size and hence the positions of the panels of the cardboard blank to be folded by the folding station 60 may vary from blank to blank.

(16) The shown folding station 60 is of exemplary nature to facilitate understanding the folding process. In a preferred embodiment, at least the front folding units, which come first into contact with a blank to be folded, are movable so that they can be moved towards a curing station.

(17) The folding station 60 forms part of an automatic packaging system, in which custom sized boxes can be created from cardboard fed into the system usually from zig-zag folded stacks of cardboard and in which items to be shipped are automatically packaged in the boxes formed. Such system is disclosed for example in WO 2014/117817 A1. Such automatic packaging system comprises a blank forming apparatus, in which the cardboard is cut and creased to form a custom sized blank, which then can be folded automatically.

(18) FIG. 4 depicts the upper part of a folding unit 70, which advantageously may be movable in two directions, namely in (and against) a processing direction, in which cardboard blanks and then, once folded, boxes are transported through the system, and in (and against) the width direction of the blanks processed, which is the orthogonal direction to the processing direction in the plane of the blanks. As will be explained later, being movable in the processing direction (and against it to return to a starting position) allows both folding blanks of different lengths and guiding the blanks resp. the boxes folded thereof towards a curing station, and being movable in and against the width direction allows, if necessary, to fold blanks of different widths.

(19) A corresponding folding station typically comprises four such folding units adapted to fold the four corner panels, the two front and rear end panels and the two side panels of a box (or a lid) to be created. FIG. 4 also shows a portion of a blank 10, namely a part of a bottom panel 12, a part of a side panel 18, a part of a rear end panel 16, and a corner panel 28. The folding unit 70 exemplarily shown in FIG. 4 is adapted to fold the rear corner panel 28 upwards, the rear end panel 16 upwards and the side panel 18 upwards. For doing so, the folding unit 70 comprises a corner panel folding element with an actuable guiding plate 72, a blank fixing element (not visible) for fixing the bottom panel 12 in position during folding the panels attached to the bottom panel 12, an end panel folding element 74 and a side panel folding element 76. The fixing element may be implemented in form of an elastic suction cup, which is connected with means for evacuating air from the suction cup so that the surrounding air pressure would press a corresponding panel placed on the fixing element to the fixing element. Depending on the specific implementation of the folding unit, such fixing element may not be necessary, for example when the folding unit is used to fold panels upward after items to be packaged have been placed on a bottom panel of a cardboard blank. Depending on the form and weight of the items, the items may fix the blank sufficiently while the side and end panels and also the corner panels attached to the end panels are being folded. However, the presence of a fixing element makes the folding of boxes with only low weight items more reliable.

(20) In the embodiment shown in FIG. 4, the guiding plate 72 has substantially the shape of a quarter circle with rounded corners. In the end position of its movement, one of its edges runs substantially along an end portion of the crease line 36 between the bottom panel 12 and the side panel 18. During movement of the end panel 16, the flat surface of the guiding plate 72 will guide the respective corner panel 28 attached to the rear end panel 16.

(21) In the situation shown in FIG. 4, guiding plate 72 is still in contact with corner panel 28, which slides along the guiding plate 72 as the end panel 16 is pushed upwards by end panel folding element 74. As the end panel folding element 74 has started pushing end panel 16 upwards, also corner panel 28 attached to it has moved upwards while being guided by guiding plate 72 to its final position approximately against crease line 36. In the shown situation, hot melt glue (not shown) will be or may have already been applied to a portion of the side panel 18 that in the final folding state comes into contact with corner panel 28. Similarly, the other corner panels will be glued to the side panels. Hitherto, the panels had to be held in place during curing of the hot melt glue by the respective side panel folding elements, thus that the folding units were blocked from processing a new blank. The invention now advantageously frees the folding units from this task.

(22) FIGS. 5 to 10 show very schematically different stages during operation of a system according to the invention, which may be used as part of a system for automatically packaging varying shipment sets in (open) boxes, which are closed separately, but which may also be used to produce lids, empty boxes or to place and glue lids onto filled boxes (in case of which of course the panels would not, as shown, be folded upwards but downwards). A system for automatically packaging varying shipment sets that employs the system shown in FIGS. 5 to 10 will—as described in the prior art mentioned above—comprise means like laser scanners for obtaining information on the overall length, width and height dimensions of a shipment set to be packaged and means like a computer for calculating, based on said information, the layout of a cardboard blank. The system will further comprise, as mentioned above, structure for cutting and creasing cardboard to have the calculated layout and an input conveyor for conveying the shipment set onto the bottom panel at least prior to folding the rear corner panels.

(23) The system shown in FIGS. 5 to 10 comprises a feeding conveyor 80 for feeding a cardboard blank 10 in a processing direction 82 into a folding station that in this case comprises four folding units folding arranged in pairs forming a pair of rear folding units, of which one folding unit 70 is visible, and a pair of front folding units, of which one folding unit 84 is visible. In the shown example, the pairs of folding units are movable relative to each other.

(24) The system also comprises one or more glue application units (not shown in these schematic drawings as these drawings are intended to show the principle of employing a a curing station) for applying glue on at least one of the panels of the blank 10 that are to be glued together and a curing station formed by a base 86 and holding structure to take over the boxes or lids or combinations of a box and a lid formed at the folding station and to guide them through the curing station while form-fittingly holding the panels that are glued together allowing the glue to cure. The glue application unit may be adapted to apply portions of hot melt glue with at least two different surface-to-volume ratios, which can contribute to speeding up the whole process as the portions having a higher surface to volume ratio may cure faster and thus fix the panels provisionally, while the other portion may contain more glue and may lead, once cured, to a stronger bond.

(25) Of the holding structure, which supports, seen in the processing direction, the sides and the bottom of—in this case an open—box, a first side guiding element 88 is visible in these schematic drawings, while a second side guiding element substantially parallel to the first side guiding element 88 is provided. The distance of the side guiding elements and the distance of the folding units in the width direction, which is the direction orthogonal to the processing direction 82 in the plane of the blank 10, are adjustable to different widths of boxes or lids or combinations of a box and a lid to be folded in the folding station. The side guiding elements 88 may for example be formed by panels or arrangements of rods and may be extendable in their length seen in the processing direction 82.

(26) The system further comprises a transport device (not shown) for transporting the box fully into and through the curing station.

(27) In the situation shown in FIG. 5, some items 90, 92, 94 forming a shipment set have been placed on blank 10, either before or after handing over the blank from the feeding conveyor 80 to the folding station, and placing may be done manually or automatically, but as mentioned, the system and in particular the curing station may also be used within other configurations, for example in systems, where no items are handled.

(28) Each folding unit 70, 84 comprises a cornel panel folding element (not shown in these schematic drawings), a blank fixing element (also not shown), an end panel folding element 74, 96 and a side panel folding element 76, 98. In a first step of the folding process according to this example, the front and rear corner panels 22, 28 and the front and rear end panels are erected as shown in FIG. 6. In FIG. 6, the parts of the items 90, 92, 94 that are no longer visible due to folding up the corner panels are shown in dotted lines.

(29) Next, the side panels, of which only side panel 18 is visible, are erected as shown in FIG. 7 by the side panel panel folding elements 76 and 98, thus an open box is formed. For sake of simplicity, the items in the box are no longer indicated. Prior to folding the side panels onto the respective corner panels, hot melt glue has been applied on at least one of the panels to be glued together. This may already have been done upon transferring the blank into the folding station.

(30) As indicated by arrow 100, the holding structure of the curing station, of which only side guiding element 88 is visible in FIG. 7, has started moving towards the folding station to take over the box.

(31) FIG. 8 depicts the situation in which the holding structure with side guiding element 88 has arrived at a position for taking over the box from the folding station. In order to do so, the front end panel folding elements, of which only element 96 is visible in FIG. 8, have returned to their initial position. Separate means not shown in FIG. 8 may be provided to take over the support of front panel 14 to prevent it from leaving its straight-up position allowing the hot melt glue to cure.

(32) FIG. 9 depicts the situation in which the box has already been partially handed over to the curing station, such that the side guiding elements contact a portion of the respective side panels and hold them in place allowing the hot melt glue to cure. In FIG. 9, the dotted lines indicate the portion of side panel 18 that has already been moved into the curing station, i.e. between the elements forming the holding structure. The movement of the box is caused by a respective movement of the rear folding units, of which only unit 70 is visible in FIG. 9, towards the front folding units, of which only unit 84 is visible here, and thus towards the holding structure. As the rear end panel folding elements, of which only element 74 is visible here, are still in their upright (or folding) position, they abut against the box just formed and push it into the curing station when the rear folding units move towards that station.

(33) FIG. 10 depicts the situation in which the box is fully in the curing station, such that the side guiding elements contact the respective side panels and hold them in place allowing the hot melt glue to cure. The rear folding units, of which only unit 70 is visible here, have returned to their starting position next to feeding conveyor 80. The rear end panel folding elements, of which only element 74 is visible here, have returned to their initial position allowing a next blank to be moved onto them. The holding structure, of which only side guiding element 88 is visible here, will start returning as indicated by arrow 102 towards its initial position, where a box can be pushed or otherwise transported out of the curing station for further processing such as (if not yet done) labelling and/or franking and/or transporting towards a lid placing station to place a lid on the box. Transporting the box fully into and through curing station may be done by a suitable transport device such as one or more movable fingers pushing the box or revolving rubber and/or vacuum belts integrated in the holding structure and pulling the box through the curing station.

(34) While in the shown embodiment both, the rear end folding units and curing station, here in particular the holding structure, are movable in and against the processing direction, other configurations are possible. For example, the rear folding units may stay in a fixed position, while the front folding units move in and against the processing direction in order to adapt to blanks of different lengths, and the curing station may move towards the front folding units for picking up a box. Likewise, all three, the rear folding units, the front folding units and the curing station may be movable in and against the processing direction in order to optimize the throughput of a respective system by freeing the folding units as early as possible for handling a next blank while ensuring sufficient support of the current box to allow the glue to cure.

(35) In a specific embodiment the front folding units 84 may start to move back towards the feeding conveyor 80 as soon as the box has been set-up, the front end panel folding elements 96 have been lowered and the side guiding elements 88 are in position adjacent to the front folding units 84 to take over the box. The side panel folding elements 98 of the front folding units 84 are still up to support the side panels 18, 20 of the box. While the front folding units move back towards the feeding conveyor, the movable side guiding elements 88 of the curing station follow the front folding units until the box has been fully moved into the curing station, such that there is a continuous form-fit support of the box by either the folding units or the curing station. The rear folding units 70 will stop transporting the box into the curing station and also start to move back towards the feeding conveyor before the front folding units reach the rear folding units and a collision of the folding units would occur. From the disclosure, it is apparent that the timing of the front folding units, the rear folding units and the guiding elements in this embodiment depends on the length of the box created.

(36) FIG. 11 shows parts of a system 110 for automatically packaging varying shipment sets in custom-sized cardboard boxes, namely an input or assembly station 112, where during operation shipment sets are placed on a custom-sized cardboard blank having a layout as described above, a glue application station 114, where glue is applied to parts of the side panels of the blank that will come in to contact with the respective corner panels, a folding station 116 comprising four folding units 118 adjustable in their position to handle differently sized blanks, a curing station 120 and a pick-up station 122, where the final folded boxes arrive when the glue has cured and are picked-up for further processing. The curing station 120 comprises holding structure for form-fittingly holding the side panels of a box erected in the folding station 116 and for guiding the boxes through the curing station. The holding structure comprises in particular two side guiding elements 124, 126 that are substantially parallel to each other while the distance between them is adjustable to different box widths.

(37) FIG. 12 shows parts of a curing station 112 in more detail. It comprises two side guiding elements 124, 126 movably mounted via blocks 128, 130 on a rail 132 such that the distance between them is adjustable to different box widths. In use, the side guiding elements 124, 126 synchronously move in opposite directions along the rail, i.e. towards to or away from each other, such that there is a fixed center line.

(38) In this embodiment, the side guiding elements are extendable in their length seen in the processing direction. To this purpose, each side guiding element 124, 126 has a fixed part 134, 136 and a movable part 138, 140, each part being formed by an assembly of parallel guide bars. Both, the fixed and the movable parts comprise a number of support rollers 142, of which for sake of clarity only some have been provided with reference numbers. The support rollers 142 carry the boxes when they are being transported through the curing station 112. As they are present on both, the fixed and the movable parts, support for the bottom of a box is provided throughout the curing station 112.

(39) In order to facilitate understanding the functioning of the extendable side guiding elements, element 124 is shown in a position, in which the movable part 138 has been moved to a partially extended position, in which it extends the length of the side guiding element 124, while movable part 140 is in a non-extended position. During operation of the curing station, the movable parts 138, 140 would be moved (if extending the side guiding elements 124, 126 is desired) synchronously by a respective linear motor 144 along a respective guide rail 146. The advantage of extendable side guiding elements is that they can provide support over a longer distance so that longer boxes can be supported. In other words, long boxes can be supported over their full length with a curing station having side guiding elements that are in the non-extended position shorter than the respective boxes.

(40) FIG. 13 shows a curing station 112 similar to that of FIG. 12, but from a different perspective. The same reference numbers as in FIG. 12 are used for similar parts. In this embodiment, a central track 148 with rows of support rollers 150 on both sides is provided. For sake of clarity, only two support rollers 150 are provided with reference numbers. For sake of clarity also the folding station 116 with folding units 118 as shown in FIG. 11 are left out of this drawing.

(41) The central track 148 accommodates a transport chain having one or more transport fingers 152, 154 which are adapted to push boxes handed over from a folding station, of which only parts like for example conveyors 156 are shown, through the curing station 112. The transport chain may have two revolving fingers and may be configured so that when one of the fingers moves with a box through the curing station, the other finger moves back at the bottom side of the chain. Advantageously, two independently controllable transport chains with one or more fingers may be provided, one chain adapted to push a box through the curing station by pressing with a finger against the rear end panel of the box, while the other may be adapted to provide support for the front end panel of the box during its transport through the curing station.

(42) When two independently controllable transport chains each with one or more fingers are provided, the system may be configured such that the finger that pushes a box through the curing station will support the front side of the next box. In such configuration, the finger may stop at the end of the curing station, when it has pushed the current box out of the curing station, and may then return to a position near the entry of the curing station, where it can contact and support the front end panel of the next box. It may then move with that box through the curing station, turn at the end of track 148 by about 90° around an end of the track to allow the box to be pushed out of the curing station. Finger 156 is shown in such position. Depending on the configuration of the transport chains and the track, the finger may then be moved above or underneath track 148 to the entry of the curing station 112 for pushing the next box through the station.

LIST OF REFERENCE NUMBERS

(43) 10 blank 12 bottom panel 14 first end panel (front end panel) 16 second end panel (rear end panel) 18 first side panel 20 second side panel 22, 24 first corner panels (front corner panels) 26, 28 second corner panels (rear corner panels) 30-44 crease lines 46-52 slots 60 folding station 62 corner panel folding element 64 rod 66 rod 68 rod 70 rear folding unit 72 guiding plate 74 end panel folding element 76 side panel folding element 74 rear end panel folding element 76 side panel panel folding element 80 feeding conveyor 82 processing direction 84 front folding unit 86 base 88 side guiding element 90 item 92 item 94 item 96 front end panel folding element 98 side panel panel folding element 100 arrow indicating movability 102 arrow indicating movability 110 system for automatically packaging varying shipment sets 112 assembly station 114 glue application station 116 folding station 118 folding unit 120 curing station 122 pick-up station 124 side guiding element 126 side guiding element 128 block 130 block 132 rail 134 fixed part 136 fixed part 138 movable part 140 movable part 142 support roller 144 linear motor 146 guide rail 148 track 150 support roller 152 transport finger 154 transport finger 156 conveyor H.sub.CP height of the corner panels H.sub.EP height of the end panels H.sub.SP height of the side panels L.sub.BP length of the bottom panel L.sub.CP length of the corner panels L.sub.SP length of the side panels W.sub.BP width of the bottom panel W.sub.EP width of the end panels