Breaker module for converter

Abstract

The present invention relates to a breaker module (8) for separating a stack (4) of juxtaposed blanks (3a, 3b) joined by a line of weakness (16). The breaker module comprises an upper pressing member (18) having first and second contact plates (19a, 19b), each of which has a pusher mechanism (32) comprising a plurality of pusher rods (34) each housed in a slot (36).

Description

[Technical Field]

[0001] The present invention relates to a breaker module for separating juxtaposed blanks in a converting machine configured to produce paper and cardboard containers, such as flat pack boxes. [Background technology]

[0002] Converting machines are used to produce packaging articles, such as blanks or boxes made from paper, cardboard, or plastic. One type of converting machine is a rotary die-cutter. This type of machine can be configured to produce blanks in the form of flatpack boxes from sheet substrates. The flatpack boxes can then be manually folded to form the boxes.

[0003] Rotary die cutters use die cutting tools to punch blanks from a sheet substrate. The punched blanks may be composite blanks comprising multiple side-by-side blanks joined by a line of weakness. A cutting device (also called a "breaker") may be used to break the line of weakness and separate the blanks from one another. Such a cutting device is disclosed in Bobst Patent EP 3445549. The cutting device includes an upper pressure member that is fixed around the line of weakness of the stack of blanks and undergoes a rotational movement, thereby separating the juxtaposed blanks.

[0004] In a cutting device, the top blank of a stack of blanks tends to adhere to the upper pressing member and become displaced relative to the position of the rest of the stack. This effect is caused by static electricity between the top blank and the upper pressing member.

[0005] Because the cutting device is sensor-driven, displacement of the upper sheet causes detection problems for the optical system. Typically, this causes the optical system to miscalculate the arrival of the subsequent stack of composite blanks. As a result, the cutting device may start cutting the stack of blanks at an incorrect position that does not coincide with the line of weakness. This results in damage to the blanks and the risk of jamming within the cutting device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 3445549 Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the prior art, it is an object of the present invention to provide a breaker module that reduces the risk of causing paper jams. [Means for solving the problem]

[0008] This object is solved by a breaker module as claimed in claim 1.

[0009] According to a first aspect of the present invention, there is provided a breaker module for separating a stack of juxtaposed blanks joined by a line of weakness. The breaker module comprises a first conveyor and a second conveyor arranged one after the other in a conveying direction of the stack. An upper pressing member is movable between a spacing position, an immobilizing position, and a breaking position. The upper pressing member comprises a first contact plate and a second contact plate, each having a contact surface configured to contact an upper blank of the stack.

[0010] Each contact plate is provided with a push-out mechanism having a plurality of push-out rods each housed in a slot, the push-out rods being vertically movable so as to be housed in the slots when the upper pressing member is in the immobilization position and the breaking position, and to protrude from the slots to push out the upper blank of the stack when the upper pressing member is moved to the separated position.

[0011] The present invention is based on the recognition that the top sheet of a stack tends to move freely and jams can be prevented if the top sheet is not displaced.

[0012] In one embodiment, the push rod protrudes from the contact surface of the upper pressing member by a predetermined protrusion distance in the separated position, which may be between 5 and 50 mm.

[0013] In one embodiment, the pusher rod is coupled to the contact plate by a fastener, the fastener comprising a coupling rod and a stopper, the stopper may be displaceable along the coupling rod to adjust the protrusion distance.

[0014] In one embodiment, the longitudinal extension of the push rod coincides with the transport direction of the stack.

[0015] In another embodiment, the longitudinal extension of the push rod is perpendicular to the conveying direction.

[0016] In a further embodiment, the longitudinal extension of the push rod is oblique to the transport direction of the stack.

[0017] In one embodiment, the pusher rod has a width that is less than the width of the slot, preferably in the range of 70% to 95% of the width of the slot.

[0018] In one embodiment, a resilient layer is provided between the slot and the push rod. The resilient layer can be bonded to the push rod. Alternatively, the resilient layer can be bonded to the bottom surface of the slot.

[0019] In one embodiment, the breaker module further comprises an optical sensor configured to detect the arrival of the leading edge of the stack and provide a control signal to a control circuit of the breaker module, the control signal being configured to activate a conveyor motor that drives the conveyor and a second motor that moves the upper pressing member to the immobilization position and the breaking position.

[0020] According to a second aspect of the present invention, there is provided a converting machine comprising a breaker module according to any one of claims 1 to 12 and a die-cutting module, the die-cutting module being arranged upstream of the breaker module in the conveying direction, the die-cutting module comprising at least one cutting tool configured to provide a line of weakness in the blank, such that the blank comprises at least first and second blanks joined together by the line of weakness and arranged side by side.

[0021] The present invention will now be described with reference to the accompanying drawings, in which like features are designated with the same reference numerals. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a converter with a breaker module. [Figure 2a] FIG. 2 is a schematic diagram of a converter breaker module. [Figure 2b] FIG. 2b is a schematic diagram of a blank suitable for processing in the breaker module of FIG. 2a. [Figure 3a] 2 is a schematic diagram of the breaker device of FIG. 1 in a separated position. [Figure 3b] 2 is a schematic diagram of the breaker device of FIG. 1 in an immobilized position. [Figure 3c] 2 is a schematic view of the breaker device of FIG. 1 in a breaking position. [Figure 4a] 3 is a schematic cross-sectional view of a pressing member of a breaker module according to an embodiment of the present invention; FIG. [Figure 4b]4b is a schematic cross-sectional view of the upper pressing member of FIG. 4a in the extrusion position; [Figure 4c] 4b is a schematic cross-sectional view of the upper pressure member of FIG. 4a in a retracted position; [Figure 5a] FIG. 10 is a bottom view of a pressure plate according to one embodiment of the present invention. [Figure 5b] FIG. 10 is a bottom view of a pressure plate according to another embodiment of the present invention. [Figure 5c] FIG. 10 is a bottom view of a pressure plate according to a further embodiment of the present invention. [Figure 6] FIG. 2 is a partial view of the top of a breaker device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention can be used with several types of converting machines, such as rotary die cutter machines or flexo folder gluer machines, however, for simplicity, the following description will refer to rotary die cutter machines.

[0024] 1 illustrates a converting machine 1 in the form of a rotary die cutter machine 1. The converting machine 1 includes multiple workstations in a modular format. While multiple configurations are possible, an exemplary converting machine 1 may include at least one auxiliary workstation such as a pre-feed module 2, a feed module 3, a printing module 4 with multiple printing units 5, a die-cutting module 6, a stacker module 7, a breaker module 8, and a palletizer module 9. A main operator interface 11 may also be provided adjacent the converting machine 1.

[0025] The feeding module 3 is configured to feed sheet substrates into the converting machine 1. The sheet substrates are converted into blanks 3 by the converting machine 1 and transported through the converting machine 1 on a transport path P along a transport direction T. Before the breaker module 8, each blank 3 may include multiple juxtaposed box blanks 3a, 3b that need to be separated.

[0026] As best seen in Figures 1, 2a, 2b and 3a-3c, the breaker module 8 is located downstream of the stacker module 7 and receives the stack 4 of superimposed blanks 3. Each blank 3 includes at least juxtaposed individual first and second blanks 3a, 3b joined by a line of weakness 16. The breaker module 8 is configured to separate each stack 4 of blanks into two stacks 4a, 4b by breaking the line of weakness 16.

[0027] The breaker module 8 includes an upper pressing member 18 and a conveyor 20. The breaker module 8 further includes a chassis 24 to which the upper pressing member 18 and the conveyor 20 are attached.

[0028] The upper pressing member 18 includes a first contact plate 19a and a second contact plate 19b.

[0029] The conveyors include a first conveyor 22a and a second conveyor 22b. The first and second conveyors 22a, 22b have a conveying direction T perpendicular to the line of weakness 16 on the stack 4.

[0030] 3a to 3c, the upper pressing member 18 is movable between a distanced position A, an immobilized position B, and a breaking position C. In the distanced position A, the upper pressing member 18 is not in contact with the stack 4. When the stack 4 is transported into the breaker module 8, the upper pressing member 18 is in the distanced position.

[0031] In the immobilization position, the upper pressure member 18 applies pressure to the upper blanks 3 of the stack 4. In this position, the first and second contact plates 19a, 19b are arranged on either side of the line of weakness 16. The upper pressure member 18 moves downwards in the vertical direction V and contacts the upper blanks 3 of the stack 4. The upper pressure member 18 descends until a pressure sufficient to immobilize the stack 4 is generated, i.e. the pressure is selected so that the distance between the conveyor 20 and the upper contact plates 19a, 19b corresponds to the sum of the thicknesses of the blanks 3 in the vertical direction V.

[0032] As shown in FIG. 3c, at the breaking position C, the second pressing member 19b and the second conveyor 22b perform a rotational movement to break the line of weakness 16.

[0033] The upper first and second contact plates 19a, 19b and the first and second conveyors 22a, 22b are vertically related in their motion. The vertically aligned first contact plate 19a and lower conveyor 22a are configured for coordinated motion. The two vertically related pairs of contact plates 19a, 19b and lower conveyors 22a, 22b can be referred to as the inlet side I and the outlet side O, respectively.

[0034] When breaking the line of weakness 16, the inlet side I remains in the immobilized position B, but the second contact plate 19b and the lower second conveyor 22b pivot together at the outlet side O. The pivoting movement causes a lateral movement of the second part 4b of the stack 4 relative to the first part 4a of the stack 4. The lateral distance between the first and second conveyors 22a, 22b therefore increases as the first and second contact plates 19a, 19b and the first and second conveyors 22a, 22b move apart.

[0035] The breaker module 8 further includes a control circuit 46 including a memory 48 and a controller 50. The memory 48 includes displacement instructions for a conveyor motor 52 mechanically coupled to the first and second conveyors 22a, 22b. The memory 48 also includes instructions for a motor 53 of the upper pressure member 18 to move and position the upper pressure member 18 in a separation position A, an immobilization position B, and a breaking position C.

[0036] The breaker module 8 may further include an optical sensor 26 configured to detect the arrival of the leading edge 5a of the stack 4 as it is transported into the breaker module 8. In this manner, the optical sensor 26 may send information to the control circuit 46 so that the conveyor 22 moves until the line of weakness 16 is located between the first contact plate 19a and the second contact plate 19b. The optical sensor 26 may be located upstream of the second conveyor 22b. For example, the sensor 26 may be disposed at the entrance to the breaker module 8. Alternatively, the optical sensor 26 may be located between the first and second contact plates 19a, 19b of the upper pressing member 18.

[0037] 4a to 4c and 5a and 5b, the contact surfaces 30 of the first and second contact plates 19a, 19b are provided with a push-out mechanism 32. The push-out mechanism 32 is configured to release the upper blank 3 in the stack 4 when the upper press member 18 returns to the separated position A. Thus, the push-out mechanism 32 pushes the upper blank 3 in the stack away from the upper press member 18. This prevents the upper blank 3 from momentarily adhering to the upper press member 18 and becoming misaligned with the rest of the stack 4.

[0038] The pusher mechanism 32 includes a plurality of elongated pusher rods 34 housed in slots 36 in the first and second contact plates 19a, 19b. The pusher rods 34 are movable in a vertical direction V.

[0039] The push rod 34 is movable between a first position P1, in which the push rod is fully housed within the slot 36, and a second position P2, in which the push rod protrudes from the contact surface 30. When the push rod 34 protrudes from the slot 36, the push rod 34 is positioned vertically below the contact surface 30. A maximum protrusion distance dp can be defined as the distance between the contact surface 30 of the contact plates 19a, 19b and the contact surface 31 of the push rod 34 at its most extended position P2. The protrusion distance dp can be between 6 and 30 mm. Preferably, the protrusion distance dp is less than 50 mm.

[0040] The push rod 34 enters the slot 36 when the pressure member 18 is pressed against the stack 4 of blanks 3. In this way, the push rod 34 is flush with or vertically above the contact surface 30 of the pressure member 18. This reduces the risk of the push rod 34 marking the upper blank 3.

[0041] When the pressing member 18 is displaced vertically upwards and returns to the separated position A, the push rod 34 moves downwards due to gravity and pushes the upper blank 3 out of the upper pressing member 18. The individual stacks 4a, 4b can then be withdrawn by the conveyor 20.

[0042] The push rod 34 is attached to the contact plate by a fastener 38. The fastener 38 includes a rod 40 that traverses the contact plate 30 and a stopper 42. The stopper 42 is adjustable. Preferably, the stopper 42 is adjustable to adjust the vertical protrusion distance dp of the push rod 34. For example, the stopper 42 can be a threaded nut. The required protrusion distance dp may vary depending on the area and weight of the blank 3. Typically, the smaller and heavier the blank 3, the smaller the protrusion distance dp needs to be.

[0043] The rod 40 may have one or more markings to define the predetermined position of the stopper 42. In one embodiment, at least one marking may provide a tactile indication to guide the stopper 42 to its predetermined position.

[0044] Each push rod 34 can move independently. Optionally, the push rods 34 on each contact plate 19a, 19b can be interconnected, which can guide the push rods 34 so that they move as a unit.

[0045] 5a, the push rod 34 can extend perpendicular to the line of weakness 16. In other words, the longitudinal extension of the push rod 34 coincides with the conveying direction T.

[0046] In another embodiment, shown in Figure 5b, the push rod 34 can extend obliquely, and thus diagonally, relative to the line of weakness 16. This ensures that the entire width of the stack 4 is in contact with at least one push rod 34. In addition, this prevents the push rod 34 from entering the fluting of the blank 3 (made of corrugated cardboard), which could otherwise cause localized deformation. The oblique push rod 34 is therefore configured to contact multiple grooves of the blank 3 simultaneously, thus distributing the contact pressure.

[0047] In a further embodiment, as shown in Figure 5c, the push rod 34 can extend perpendicular to the conveying direction T. The push rod 34 is therefore parallel to the weakened line 16 on the blank 2. This can also prevent damage to the blank 2, as the grooves in the cardboard often extend in the conveying direction T.

[0048] As shown in Figure 6, the push rod 34 may be connected to earth (and thus "grounded"). To this effect, an electrical wire 50 may be connected to the push rod 34. The electrical wire 50 may be connected to a fastener 38 or to another protruding connection element that is connected to the push rod 34. The electrical wire 50 may extend beyond the length of the contact plates 19a, 19b and connect to the chassis 24. The electrical wire 50 may be connected directly to the chassis 24 or indirectly to the chassis 24 via another machine component. Since the chassis 24 is also grounded, this grounds the electrical wire 50.

[0049] Alternatively, the material of the push rod 34 can be selected to be less conductive than steel, thus making the push rod 34 less conductive to static electricity. For example, the material can be an insulating material in the form of a coating.

[0050] By preventing electrostatic energy, the upper blank 3 of the stack 4 can be prevented from sticking to the pusher rod 34 .

[0051] Optionally, the slot 36 can have a bottom with a resilient layer, which can reduce noise and wear on the upper push member 19 when the push rod 34 enters the slot 36. Alternatively, the resilient layer is provided on the top surface of the push rod 34. The resilient layer can be bonded to the push rod 34 with an adhesive. In this way, the resilient layer can be replaced along with the push rod 34. [Explanation of symbols]

[0052] 3a Blank 3b Blank 4 Stacks 8 Breaker Module 16 Weak Lines 18 Upper pressing member 19a First contact plate 19b Second contact plate 32 Extrusion mechanism 34 Extrusion Rod 36 slots

Claims

1. A breaker module (8) for separating a stack (4) of juxtaposed blanks (3a, 3b) joined together by a line of weakness (16), comprising: a first conveyor (22a) and a second conveyor (22b) arranged in sequence in the transport direction (T) of the stack; an upper pressing member 18 movable between a separation position (A), an immobilization position (B), and a breaking position (C); Equipped with the upper pressing member (18) comprises a first contact plate (19a) and a second contact plate (19b), each of said contact plates having a contact surface (30) configured to contact an upper blank (3) of the stack; Each of the contact plates includes a pusher mechanism (32), the pusher mechanism including a plurality of pusher rods (34) each housed in a slot (36); The push rod is vertically movable so as to be accommodated in the slot (36) when the upper pressing member (18) is in the immobilization position (B) and the breaking position (C), and to protrude from the slot (36) to push out the upper blank (3) of the stack (4) when the upper pressing member (18) is moved to the separation position (A).

2. 2. The breaker module according to claim 1, wherein the push rod protrudes from the contact surface (30) of the upper pressing member (18) by a protrusion distance (dp) in the separated position (A), the protrusion distance being between 5 and 50 mm.

3. 3. The breaker module of claim 1, wherein the push rod is connected to the contact plate (19a, 19b) by a fastener, the fastener comprising a connecting rod (40) and a stopper (42).

4. The breaker module of claim 3 , wherein the stopper is displaceable along the connecting rod to adjust the protrusion distance.

5. 5. Breaker module according to any one of claims 1 to 4, wherein the longitudinal extension of the push rod coincides with the conveying direction (T) of the stack (4).

6. 5. Breaker module according to any one of claims 1 to 4, wherein the longitudinal extension of said push rod is perpendicular to said conveying direction (T).

7. 5. A breaker module according to any one of claims 1 to 4, wherein the longitudinal extension of the push rod is oblique to the conveying direction (T) of the stack (4).

8. 8. The breaker module according to any one of claims 1 to 7, wherein the push rod has a width (w1) that is smaller than the width (w2) of the slot, preferably in the range of 70% to 95% of the slot.

9. The breaker module of claim 1 , wherein a resilient layer is provided between the slot and the push rod.

10. The breaker module of claim 9 , wherein the resilient layer is coupled to the push rod.

11. The breaker module of claim 9 , wherein the resilient layer is bonded to a bottom surface of the slot.

12. 12. The breaker module of claim 1, further comprising an optical sensor (26) configured to detect the arrival of a leading edge (5a) of the stack (4) and to provide a control signal to a control circuit (46) of the breaker module, the control signal being configured to activate a conveyor motor (52) that drives the conveyor (20) and a second motor (53) that moves the upper pressing member (18) to the immobilization position and the breaking position.

13. 13. A converting machine comprising a breaker module (8) according to any one of claims 1 to 12 and a die-cutting module (6), the die-cutting module being arranged upstream of the breaker module in the conveying direction, the die-cutting module comprising at least one cutting tool configured to create a line of weakness (16) on a blank (3), the blank (3) comprising at least first and second blanks (3a, 3b) joined together by the line of weakness and arranged side by side.

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