UNIT FOR FORMING A PLATE ELEMENT FOR MANUFACTURING FOLDING BOXES

Abstract

The unit for forming a plate element (2) for the continuous flow manufacturing of folding boxes (CA1, CA2) from plate elements (3), the plate elements (3) being successively inserted into the unit (2) and moving in a feed direction (FD), comprising pairs of rotary cylindrical shafts (2001-2031, 200.sub.2-203.sub.2), carrying forming tooling, which forms the plate elements (4) using slitting, creasing and cutting operations, comprising a cutting unit (21), and pairs of rotary cylindrical shafts (200.sub.1-203.sub.1, 200.sub.2-203.sub.2),

Claims

1. A forming unit for continuous production of folding boxes from a plurality of plate elements, wherein the plurality of plate elements are successively inserted into the forming unit and move in a feed direction, the forming unit comprising: a first slotter unit and a second slotter unit, each provided with pairs of rotating cylindrical shafts carrying respective forming tools which perform slitting, creasing, and cutting operations to form a plate element among the plurality of plate elements, and a cutting unit in which the pairs of rotating cylindrical shafts and the cutting unit work together to create, in the formed plate element, front and rear juxtaposed folding box layers, wherein two pairs of shafts among the pairs of rotating cylindrical shafts of the first slotter unit are configured to work together to provide central slits in each plate element aligned on a central transverse axis of the plate element, and two pairs of shafts among the pairs of rotating cylindrical shafts of the second slotter unit are configured to work together to respectively create rear edge slits in the rear layer and front edge slits in the front layer, and wherein the pairs of rotating cylindrical shafts each carry a single slitting tool, wherein an angular position of at least one of the pairs of rotating cylindrical shafts is adjustable with respect to a feed position in the feed direction of the plate element, and wherein the first slotter unit is arranged upstream of the second slotter unit in the feed direction and is configured to provide the central slits before the second slotter unit creates the rear edge slits and the front edge slits.

2. The forming unit according to claim 1, wherein the cutting unit comprises a perforation blade perpendicular to the feed direction, and which allows the front and rear juxtaposed folding box layers to be serially associated and connected to each other by attachment points.

3. The forming unit according to claim 1, further comprising: a pair of shafts arranged to perform cutting operations of a box flap in the rear layer and pre-creasing operations for folding lines in the front and rear layers.

4. The forming unit according to claim 3, further comprising: a pair of shafts arranged to perform cutting operations of a box flap in the front layer and creasing operations for the pre-creased folding lines in the front and rear layers, and a pair of shafts arranged to perform crushing operations on the front and rear layers.

5. The forming unit according to claim 1, wherein the first slotter unit and the second slotter unit are serially associated, and have a same architecture with regard to the pairs of rotating cylindrical shafts.

6. The forming unit according to claim 5, wherein the first and second slotter units each comprises four pairs of shafts aligned and arranged transversely to the feed direction, and the first and second slotter units are associated so as to form an alignment of eight pairs of shafts.

7. The forming unit according to claim 6, wherein second and fourth pairs of shafts of the first slotter unit work together to make central slits in the plate element aligned with a central longitudinal axis of the plate element, the second pair of shafts comprising a tool-holder shaft carrying a first slitting tool arranged to provide first central slit portions, and the fourth pair of shafts comprising a tool-holder shaft with a second rotating tool arranged to provide second central slit portions, wherein each central slit is formed by a combination of the first central slit portion and the second central slit portion, and has a length determined by an overlap area between the first and second central slit portions which is defined by angular positional adjustments of the first slitting tool and the second rotating tool.

8. The forming unit according to claim 7, further comprising a first box flap cutter mounted on a third pair of shafts of the first slotter unit, the first box flap cutter performing cutting operations on a first box tab on a proximal lateral edge of the plate element.

9. The forming unit according to claim 8, further comprising a first pre-creasing device mounted on the third pair of shafts of the first slotter unit, the first pre-creasing device performing pre-creasing operations on the plate element in order to produce fold lines in the front and rear folding box layers.

10. The forming unit according to claim 9, wherein: a second pair of shafts of the second slotter unit comprises a cylindrical tool-holding shaft carrying a third slitting tool arranged to make back edge slits in the plate element, and a fourth pair of shafts of the second slotter unit comprises a tool-holding shaft carrying a fourth slitting tool arranged to make front edge slits in the plate element.

11. The forming unit according to claim 10, further comprising: a second box flap cutter mounted on a third pair of shafts of the second slotter unit, the second box flap cutter performing cutting operations on a second box tab on the proximal lateral edge of the plate element.

12. The forming unit according to claim 11, further comprising: a final creasing device mounted on the third pair of shafts of the second slotter unit, the final creasing device performing final creasing operations on the plate element of the fold lines in the front and rear folding box layers.

13. The forming unit according to claim 12, further comprising: an edge cutter mounted on one of the first and second slotter units and arranged to perform an edge cutting operation on a distal lateral edge of the plate element, wherein a first pair of shafts of the first slotter unit is configured to feed the plate element, and a the first pair of shafts of the second slotter unit comprises a crushing device arranged to crush a thickness of a proximal lateral strip and a distal lateral strip of the plate element.

14. The forming unit according to claim 1, wherein the cutting unit is a rotary cutter with rotating cylindrical shafts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further advantages and characteristics of this invention will become more apparent from the following detailed description of one particular embodiment of the invention, with reference to the attached drawings, in which:

[0027] FIG. 1 is a diagram showing a process for the production of folding boxes of the prior art;

[0028] FIG. 2 is a diagram showing different states of processing a plate element in a process to manufacture folding box packaging using the unit according to this invention;

[0029] FIG. 3 is a diagram showing a general architecture of a unit for forming a plate element according to this invention;

[0030] FIG. 4 is a diagram showing examples of center slits of different lengths that may be made in a plate element with the plate element forming unit of FIG. 3; and

[0031] FIG. 5 is a diagram showing examples of plate elements that may be produced with the unit for forming a plate element of FIG. 3 to manufacture folding boxes of different sizes.

[0032] The longitudinal direction is defined with reference to the direction of movement or feed of the plate elements in the package manufacturing line, along their longitudinal centerline. The transverse direction is defined as the direction perpendicular in a horizontal plane to the scrolling direction of the plate elements. The upstream and downstream directions are defined with reference to the direction of movement of the plate elements, along the longitudinal direction throughout the package manufacturing line, from the line entrance to the line exit. The proximal and distal edges of the plate element are defined in this non-limiting example with respect to the conductive side and the opposite conductive side of the machine and the unit for processing a plate element as the plate element moves in the horizontal plane.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] With reference to FIGS. 2-5, a particular embodiment 2 of a unit for forming a plate element according to the invention, in the form of corrugated sheets, is now described by way of example.

[0034] The general architecture of the unit for forming a plate element 2 is visible in FIG. 3. In FIG. 3, the unit for forming a plate element 2 is shown associated with a cutting unit 21, the function of which will become clear in the following description.

[0035] The plate elements, in their various processing states, are all referred to by the numeral 3 in FIGS. 2 and 3, with index letters A, B0, B and C associated with the numeral 3 indicating the processing state of the plate element under consideration.

[0036] The plate element 3 is shown in FIG. 2 in the different processing states explained above, with the labels 3.sub.A, 3.sub.B, and 3.sub.C.

[0037] The direction of the plate elements 3 feed in the unit for forming a plate element 2, and in the package production line in which it is included, from upstream to downstream is indicated by arrow FD in FIGS. 2 and 3. The plate elements 3 are conveyed and processed in the unit for forming a plate element 2 in a transverse arrangement, i.e., with their longitudinal center axis AL being perpendicular to the feed direction FD.

[0038] The plate element 3.sub.A, shown in FIG. 2, is typically formed from a rectangular plate, for example here from corrugated board, which is to be processed to form two folding boxes CA1 and CA2. The plate element 3.sub.A, for example, is here a plate element that has been printed by a printing unit placed upstream of the unit for forming a plate element 2 in a package production line.

[0039] As visible in FIG. 2, the printed plate element 3.sub.A here has two printed areas 30.sub.1 and 30.sub.2, located on either side with respect to the longitudinal centerline AL of the plate element. The printed areas 30.sub.1 and 30.sub.2 belong respectively to two layers, P1 and P2, in the plate element. The two layers P1 and P2, correspond respectively to the folding boxes CA1 and CA2, to be made from the plate element, with the aid of the unit for forming a plate element 2. In the plate element, layers P1 and P2 are arranged transversely to the feed direction FD in a side-by-side relationship.

[0040] The unit for forming a plate element 2 receives the printed plate element 3.sub.A as input, processes it and outputs a formed plate element 3.sub.B in which processing operations have been carried out to obtain the two layers P1 and P2. The processing operations specifically comprise, slitting, cutting and slitting operations to form box sides 31, body flaps 32 and two box tabs 33.sub.1 and 33.sub.2 for layers P1 and P2 of the plate element.

[0041] The formed plate element 3.sub.B comprises center slits 34.sub.12 and front edge slits 34.sub.1 and rear edge slits 34.sub.2. The central slits 34.sub.12 are aligned along the longitudinal centerline AL and participate in forming the box sides 31 and box flaps 32 of layers P1 and P2. The front edge slits 34.sub.1 are formed on a longitudinal front edge 35.sub.AV of the plate element and participate in the formation of the box sides 31 and box flaps 32 of layer P1. The rear edge slits 34.sub.2 are formed on a longitudinal rear edge 35.sub.AR of the plate element and participate in the formation of the box sides 31 and box flaps 32 of layer P2. The box tabs 33.sub.1 and 33.sub.2 are formed on the proximal lateral edge 38 of the plate element.

[0042] The formed plate element 3.sub.B also has creasing 36 to form future fold lines, which are created by creasing operations in the unit for forming a plate element 2.

[0043] The plate element 3C is obtained after the processing operation performed by the cutting unit 21 on the plate element 3.sub.B. The cutting unit 21 performs selective cuts to form attachment points 37. The plate element 3C thus has layers P1 and P2 which are now connected only by the attachment points 37.

[0044] The plate element 3.sub.C is then processed by a folding-gluing unit (not shown), which performs a folding operation and glues the box flaps 33.sub.1 and 33.sub.2 to corresponding box sides to obtain a folded assembly 4 formed by the two folding boxes CA1 and CA2 connected by the attachment points 37, the two folding boxes CA1 and CA2 corresponding to layers P1 and P2 respectively. The attachment points 37 are broken, later in the manufacturing process, to allow the folding boxes CA1 and CA2 to be separated.

[0045] The angular position of at least one of the slitting shafts 201.sub.1, 203.sub.1, 201.sub.2, 203.sub.2 is adjustable relative to the feed position in the feed direction (FD) of the plate element. The angular position α may be defined as the position of a reference point P (predefined) on the circumference of the slitting shaft 201.sub.1, 203.sub.1, 201.sub.2, 203.sub.2 in relation to the feed surface S upon which the plate elements 3 are transported. This angle α is measured between the reference point P on the slitting cylinder/shaft 201.sub.1, 203.sub.1, 201.sub.2, the slitting cylinder axis X, and the plate feed surface S.

[0046] The general architecture and operation of the unit for forming a plate element 2 is now described in detail below with particular reference to FIG. 3.

[0047] The plate elements are successively inserted, one by one, into the unit for forming a plate element 2 for processing, with an insertion rate corresponding to a machine step upon which the various pieces of equipment of the package production line are synchronized, thus, various pieces of equipment make up unit 2.

[0048] In accordance with the invention, the unit for forming a plate element 2 is formed by the serial association of two units for processing a plate element 20.sub.1 and 20.sub.2, known as “slotter” units, having a same general architecture. The first unit 20.sub.1 is traversed before the second unit for processing a plate element 20.sub.2 by the plate element moving in the feed direction FD. Both units for processing a plate element 20.sub.1 and 20.sub.2 are of the type described in WO 2013/029768.

[0049] In the unit for forming a plate element 2, the performance of processing operations on the plate element is optimized, by distributing these processing operations judiciously between the two units for processing a plate element 20.sub.1 and 20.sub.2.

[0050] Here, the units for processing a plate element 20.sub.1 and 20.sub.2 each comprise four pairs of rotating cylindrical shafts. Thus, the unit for forming a plate element 2 formed by the combination of the plate element processing units 20.sub.1 and 20.sub.2 comprises eight pairs of rotary cylindrical shafts, labeled 200.sub.1 to 203.sub.1 for the first unit for processing a plate element 20.sub.1 and 200.sub.2 to 203.sub.2 for the second unit 20.sub.2. The eight pairs of rotating cylindrical shafts, 200.sub.1 to 203.sub.1 and 200.sub.2 to 203.sub.2, are spaced apart from each other by the same center distance AX. The length of the center distance AX typically corresponds to a minimum plate element size that may be processed in the unit for forming plate element 2.

[0051] The first unit for processing a plate element 20.sub.1 processes the plate element 3.sub.A to produce a preformed plate element 3.sub.B0 visible in FIG. 3. In the first unit 20.sub.1, the first pair of rotating cylindrical shafts 200.sub.1 is dedicated to feeding the plate element.

[0052] The preformed plate element 3.sub.B0 comprises central slits 34.sub.12 that have been cut by suitable tools 51.sub.1 and 53.sub.1 provided on the second and fourth pairs of rotating cylindrical shafts 201.sub.1 and 203.sub.1, respectively. The tools 51.sub.1 and 53.sub.1 are carried by rotating tool-holder shafts (upper cylindrical shafts) of the second and fourth pairs of rotating cylindrical shafts 201.sub.1 and 203.sub.1, respectively.

[0053] The tools 51.sub.1 and 53.sub.1 typically each comprise cutting blades that conform to the cylindrical shape of the rotating tool-holder shafts. In each rotary tool shaft, a plurality of cutting blades are transversely spaced and mounted in correspondence with central positions PC1 to PC4 defined in the plate element 3.sub.B0, on the longitudinal centerline AL, at which the central slits 34.sub.12 are to be made.

[0054] The tools 51.sub.1 and 53.sub.1 are arranged and mounted on their respective rotating tool-holder shafts in such a way that a length L of the center slits 34.sub.12 in the plate element 3.sub.B0 may be set, and thus configure unit 2 for different folding box formats. The length L of the center slits 34.sub.12 is adjusted by changing the angular position (α) of tools 51.sub.1 and 53.sub.1 on their respective rotating tool-holder shafts.

[0055] By way of example, shown in FIG. 4 are three central slits 34A.sub.12, 34B.sub.12, and 34C.sub.12, having respective lengths L.sub.A, L.sub.B, and L.sub.C, made by unit 2 with a single set of tools 51.sub.1 and 53.sub.1. These three central slits 34A.sub.12, 34B.sub.12 and 34C.sub.12, are obtained with three distinct setting configurations respectively for tools 51.sub.1 and 53.sub.1 for different folding boxes.

[0056] The tools 51.sub.1 and 53.sub.1 are similar and respectively cut slit portions PR.sub.1 and PR.sub.3, having the same length LO. As an example, the length LO is considered here equal to 150 mm. The tools 51.sub.1 and 53.sub.1 may also have a different development.

[0057] The central slit 34A.sub.12 of length L.sub.A is the maximum length slit that is achievable with tools 51.sub.1 and 53.sub.1. In this first setup configuration, tools 51.sub.1 and 53.sub.1 are mounted on their respective rotating tool-holder shafts at the first angular positions that make it possible to obtain the center slit 34A.sub.12 without overlap between slit portions PR.sub.1 and PR.sub.3. The length LA obtained here is L.sub.A=2.Math.LO=300 mm.

[0058] The central slit 34B.sub.12 of length L.sub.B is the intermediate length slit that is achievable with tools 51.sub.1 and 53.sub.1. In this second setup configuration, tools 51.sub.1 and 53.sub.1 are mounted on their respective rotary tool-holder shafts at the second angular positions that make it possible to obtain the center slit 34B.sub.12 with a partial overlap of LO/13 between slit portions PR.sub.1 and PR.sub.3. Length LB obtained here is L.sub.B=2.Math.LO−LO/3=250 mm.

[0059] The central slit 34B.sub.12 of length L.sub.C is the minimum length slit that is achievable with tools 51.sub.1 and 53.sub.1. In this third setup configuration, tools 51.sub.1 and 53.sub.1 are mounted on their respective rotary tool-holder shafts at the third angular positions that make it possible to obtain the center slit 34C.sub.12 with a partial overlap of LO between slit portions PR.sub.1 and PR.sub.3. The length L.sub.C obtained here is L.sub.C=LO=150 mm.

[0060] The unit for forming a plate element 2 according to the invention thus allows, with different angular settings of the same set of tools 51.sub.1 and 53.sub.1, the production of central slits 34.sub.12 having a length L of between 2.Math.LO and LO, i.e., in the above example, a length L of between 150 mm and 300 mm.

[0061] Referring again more in particular to FIG. 3, the first unit for processing a plate element 20.sub.1 also performs complementary first processing operations that are performed by tool devices associated with the third pair of rotating cylindrical shafts 202.sub.1. These first complementary processing operations comprise cutting operations of the box tab 33.sub.2 of layer P2 and pre-creasing operations for making pre-creasing 36 of the future folding lines in layers P1 and P2.

[0062] A cutting device 52.sub.1, mounted on the tool shaft of the third pair of rotating cylindrical shafts 202.sub.1, is provided to perform cutting operations of the box tab 33.sub.2 on the proximal lateral edge 38 of the plate element. The cutting device 52.sub.1 provides beveled cuts on the front and rear edges of the box tab 33.sub.2, as visible on the preformed plate element 3.sub.B0 in FIG. 3.

[0063] A pre-creasing device (not shown) is also mounted on the third pair of rotating cylindrical shafts 202.sub.1. This pre-creasing device performs pre-creasing 36 on the plate element. In this way, the thickness of the plate element is partially crushed along continuous lines, in order to make the fold lines in layers P1 and P2. The pre-creasing is set with a creasing rate TR, to obtain a pre-creased board thickness E.sub.PR=TR.Math.E.sub.N, with E.sub.N being the nominal thickness of the board.

[0064] The second unit for processing a plate element 20.sub.2 processes the plate element 3.sub.B0 and outputs the formed plate element 3.sub.B visible in FIGS. 2 and 3. The second plate element processing unit 20.sub.2 supplements the processing operations performed on the first plate element processing unit 20.sub.1 with other processing operations to complete the forming of the plate element.

[0065] The second unit for processing a plate element 20.sub.2 performs the front edge slits 34.sub.1 and the back edge slits 34.sub.2, as well as additional second processing operations.

[0066] The front edge slits 34.sub.1 and the back edge slits 34.sub.2 are cut by suitable tools 53.sub.2 and 51.sub.2, visible in FIG. 3, respectively, equipped with the fourth and second pairs of rotating cylindrical shafts 203.sub.2 and 201.sub.2 of the second unit for processing a plate element 20.sub.2. The tools 53.sub.2 and 51.sub.2 are carried by rotating tool shafts (upper cylindrical shafts) of the fourth and second pairs of rotating cylindrical shafts 203.sub.2 and 201.sub.2 of the second unit for processing a plate element 20.sub.2, respectively, and are similar to the tools 51.sub.1 and 53.sub.1, used for central slitting 34.sub.12.

[0067] The tools 51.sub.2 and 53.sub.2 are arranged and mounted on their respective rotating tool shafts such that they can set a length of the front and rear edge slits 34.sub.1 and 34.sub.2 equal to half L/2 of the length L of the center slits 34.sub.12. The length L/2 of the front and rear edge slits 34.sub.1 and 34.sub.2, between LO and LO/2 depending on the length of the center slits 34.sub.12, is adjusted by changing the angular position of the tools 51.sub.2 and 53.sub.2, on their respective rotating tool shafts, so as to configure the unit 2 for different folding box sizes.

[0068] The second complementary processing operations comprise box flap cutting operations 33.sub.1 of layer P1, final creasing operations to complete the fold line creases 36 in layers P1 and P2, a first box flap crushing operation, a second distal lateral edge crushing operation 39, and an edge cutting operation on a distal lateral edge 39 of the plate element. The second complementary processing operations utilize tool devices associated with the third pair of rotating cylindrical shafts 202.sub.2 and the first pair of rotating cylindrical shafts 200.sub.2 of the second unit for processing a plate element 20.sub.2.

[0069] A cutting device 52.sub.2, mounted on the tool shaft of the third pair of rotating cylindrical shafts 202.sub.2, is provided to perform cutting operations of the box tab 33.sub.1 on the proximal lateral edge 38 of the plate element. The cutting device 52.sub.2 provides beveled cuts on the front and rear edges of the box tab 33.sub.1, as visible on the preformed plate element 3.sub.B in FIG. 3.

[0070] A pre-creasing device (not shown) is also mounted on the third pair of rotating cylindrical shafts 202.sub.2. This final creasing device complements the pre-creasing operations performed in the first unit for processing a plate element 20.sub.1 to obtain a desired final value, for the creasing rate TR of the folding lines.

[0071] A first box tab crushing device (not shown) is mounted on the first pair of rotating cylindrical shafts 200.sub.2 of the second unit for processing a plate element 20.sub.2. This first box tab crushing device crushes the thickness of the proximal lateral strip of the plate element at the proximal lateral edge 38, the width of this proximal strip being substantially equal to the width of the box tabs 33.sub.1 and 33.sub.2. A second crushing device crushes the thickness of a distal lateral strip of the plate element at the distal lateral edge 39. Crushing this proximal strip and this distal strip makes it possible to obtain box tabs 33.sub.1 and 33.sub.2 and the opposite distal lateral edge 39 having a reduced thickness, in order to subsequently avoid an excess thickness in the folded assembly 4 (cf. FIG. 2), where the tabs are glued to the corresponding box flanks.

[0072] The edge cutting operation on the distal lateral edge 39 of the plate element is performed by an edge cutter (not shown) installed in the second unit for processing a plate element 202.

[0073] As visible in FIG. 3, the cutting unit 21 is located downstream of the second unit for processing a plate element 20.sub.2 for receiving the formed plate element 3.sub.B. The cutting unit 21 is typically a rotary cutter with rotating cylindrical shafts. The cutting unit 21 outputs the plate element 3.sub.C incorporating the attachment points 37 between layers P1 and P2.

[0074] The unit for forming a plate element 2 according to this invention is designed with a modular approach. In fact, the unit for forming a plate element 2 is created by associating two similar units for processing a plate element which may be modular equipment from a package manufacturing line.

[0075] The unit for forming a plate element 2 according to this invention is designed to allow maximum flexibility in the manufacture of folding boxes of different sizes. By way of illustration, FIG. 5 shows three formed plate elements, FC1, FC2 and FC3, which may be produced with the unit for forming a plate element 2 and corresponding to folding boxes of different sizes.

[0076] The plate elements FC1 and FC2 have different widths, 800 mm and 650 mm respectively, but with slits of the same dimensions respectively, 240 mm and 120 mm for the center and edge slits.

[0077] The plate elements FC2 and FC3 have the same width of 650 mm, but with different slit sizes, FC3 having center and edge slits of 160 mm and 80 mm respectively.

[0078] The combination of the unit for forming a plate element 2 with the cutting unit 21 provides a plate element forming assembly capable of providing a plate element, with two layers and their attachment points, ready to be folded and glued to make two folding boxes.

[0079] The forming unit as well as the plate element forming assembly according to the invention make it possible to substantially increase the production rate of folding boxes compared to the prior art.

[0080] The invention is not limited to the particular embodiment which was described herein by way of example. The person skilled in the art, depending on the applications of the invention, will be able to make various modifications and variants falling within the scope of protection of the invention.