EP4642720A1

EP4642720A1 - Breaker module for a converting machine

Info

Publication number: EP4642720A1
Application number: EP23833733.1A
Authority: EP
Inventors: Maxime BRENAUT; Pierre Brun
Original assignee: Bobst Lyon SAS
Current assignee: Bobst Lyon SAS
Priority date: 2022-12-28
Filing date: 2023-12-18
Publication date: 2025-11-05
Also published as: CN120435430A; JP2025542429A; WO2024141297A1; KR20250119643A

Abstract

The present invention relates to a breaker module (8) for separating stacks (4) of juxtaposed blanks (3a, 3b) joined together by frangible lines (16). The breaker module comprises an upper pressing member (18) comprises a first and second 5 contact plates (19a, 19b) where each contact plate is provided with an ejection mechanism (32) comprising a plurality of ejection rods (34) each received in a slot (36).

Description

BREAKER MODULE FOR A CONVERTING MACHINE

Field of the invention

The present invention relates to a breaker module for separating juxtaposed blanks in a converting machine. The converting machine being configured to produce paper and cardboard containers, such as flat-packed boxes.

Background

Converting machines are used for producing packaging items, such as blanks or boxes made from paper, cardboard or plastics. One type of a converting machine is a rotary die-cutter machine. This type of machine may be configured to produce blanks in the form of flat-packed boxes from sheet substrates. The flat-packed boxes can be manually folded to form a box.

The rotary die-cutter machine uses a die-cutting tool in order to punch out a blank from the sheet substrate. The punched-out blank may be a composed blank comprising several side-by-side located blanks which are connected by frangible lines. A severing device (also referred to as a “breaker”) can be used for rupturing the frangible lines and to separate the blanks from each other. Such a severing device is disclosed in the Bobst patent EP3445549. The severing device comprises an upper pressing member which is immobilizing and performing a rotating movement around the frangible line of the stack of blanks, whereby the juxtaposed blanks are separated.

In the severing device, the upper blank in the stack has a tendency to stick to the upper pressing member and becomes displaced in relation to the position of the remaining stack. This effect is caused by static electricity between the upper blank and the upper pressing member.

As the severing device operates with sensors, the displacement of the upper sheet causes a detection problem for the optical system. Typically, this causes the optical system to miscalculate the arrival of a subsequent stack of composed blanks. Consequently, the severing device may then start breaking a stack of blanks in the wrong position which is not aligned with the frangible lines. The results in a risk of damage to the blanks and a paper jam in the severing device.

Summary

In view of the prior art, it is an object of the present invention to provide a breaker module with a reduced risk of causing a paper jam.

This object is solved by a breaker module according to claim 1 .

According to a first aspect of the present invention, there is provided a breaker module for separating stacks of juxtaposed blanks joined together by frangible lines. The breaker module comprises a first conveyor and a second conveyor arranged one after the other in a direction of transportation of the stack. An upper pressing member is mobile between a clearing position, an immobilizing position and a rupturing position. The upper pressing member comprises a first contact plate and a second contact plate, each contact plate having a contact surface configured to contact an upper blank in the stack.

Each contact plate comprises an ejection mechanism comprising a plurality of ejection rods each received in a slot, and wherein the ejection rods are vertically movable so as to be received within the slots when the pressing member is in the immobilizing position and rupturing position, and to protrude from the slots and eject the upper blank in the stack when the pressing member is moved into the clearing position.

The invention is based on a realization that the upper sheet of the stack tends to move freely, and a paper jam can be prevented if the upper sheet is not displaced.

In an embodiment, the ejection rods protrude at a protrusion distance from the contact surface of the upper pressing member in the clearing position. The protrusion distance may be between 5 and 50 mm.

In an embodiment, the ejection rods are connected to the contact plates by a fastener, the fastener comprising a connection rod and a stopper. The stopper may be displaceable along the rod such as to adjust the protrusion distance.

In an embodiment, a longitudinal extension of the ejection rods coincides with the direction of transportation of the stack. In another embodiment, the longitudinal extension of the ejection rods is perpendicular in relation to the direction of transportation.

In a further embodiment, a longitudinal extension of the ejection rods is oblique in relation to the direction of transportation of the stack.

In nan embodiment, the ejection rods have a width which is smaller than the width of the slot, and preferably within the range of 70% to 95% of the slot.

In an embodiment, a resilient layer is provided between the slots and the ejection rods. The resilient layer may be connected to the ejection rods. Alternatively, the resilient layer is connected to a bottom surface of the slot.

In an embodiment, the breaker module further comprises an optical sensor configured to detect the arrival of a front leading edge of the stack and provide a control signal to a control circuitry of the breaker module, and wherein the control signal is configured to initiate a conveyor motor to drive the conveyor and a second motor to move the upper pressing member into the immobilizing position and the rupturing position.

According to a second aspect of the present invention, there is provided a converting machine comprising a breaker module according to any one of the preceding claims and a die-cutting module, the die-cutting module being arranged upstream of the breaker module in the direction of transportation, wherein the diecutting module comprises at least one cutting tool configured to provide a frangible line on a blank such that the blank comprises at least a first and a second juxtaposed blanks joined together by the frangible line.

Brief description of the drawings

The invention will now be described with reference to the appended drawings, in which like features are denoted with the same reference numbers and in which:

Fig. 1 is a schematic view of a converting machine comprising a breaker module;

Fig. 2a is a schematic view of a breaker module for a converting machine;

Fig. 2b is a schematic view of a blank suitable for processing in the breaker module of figure 2a; Fig. 3a is a schematic diagram of the breaker device of figure 1 in a clearing position;

Fig. 3b is a schematic diagram of the breaker device of figure 1 in an immobilizing position;

Fig. 3c is a schematic diagram of the breaker device of figure 1 in a rupturing position;

Fig. 4a is a schematic cross-sectional view of a pressing member for a breaker module according to an embodiment of the present invention;

Figs. 4b and 4c are schematic cross-sectional views of the upper pressing member in fig. 4a in an ejection position and a retracted position, respectively.

Figure 5a is a bottom view of a pressing plate according to an embodiment of the present invention;

Figure 5b is a bottom view of a pressing plate according to another embodiment of the present invention;

Figure 5c is a bottom view of a pressing plate according to a further embodiment of the present invention; and

Figure 6 is a partial view of an upper portion of the breaker device according to an embodiment of the present invention.

Detailed description

The present invention may be used in different types of converting machines, such as rotary die-cutter machines or flexo-folder gluer machines. However, for simplicity, reference will be made to a rotary die-cutter machine in the following description.

Figure 1 illustrates a converting machine 1 in the form of a rotary die-cutter machine 1. The converting machine 1 comprises a plurality of workstations in the form of modules. Several configurations are possible, but an exemplary converting machine 1 may comprise a prefeeder module 2, a feeder module 3, a printing module 4 comprising a plurality of printing units 5, a die-cutting module 6, a stacker module 7, a breaker module 8 and at least one auxiliary workstation such as a palletizer module 9. A main operator interface 11 may also be provided in the proximity of the converting machine 1.

The feeder module 3 is configured to feed sheet substrates into the converting machine 1 . The sheet substrates are transformed into blanks 3 by the converting machine 1 and are transported on a transportation path P along a direction of transportation T through the converting machine 1. Before the breaker module 8, each blank 3 may comprise a plurality of juxtaposed box blanks 3a, 3b which need to be separated.

As best seen in figures 1 , 2a, 2b and 3a to 3c, the breaker module 8 is located downstream of the stacker module 7 and receives a stack 4 of superposed blanks 3. Each blank 3 comprises at least a first and a second juxtaposed individual blanks 3a, 3b which are connected by frangible lines 16. The breaker module 8 is configured to separate each stack 4 of blanks into two stacks 4a, 4b by rupturing the frangible lines 16.

The breaker module 8 comprises an upper pressing member 18 and a conveyor 20. The breaker module 8 further comprises a chassis 24 to which the upper pressing member 18 and the conveyor 20 are mounted.

The upper pressing member 18 comprises a first contact plate 19a and a second contact plate 19b.

The conveyor comprises a first conveyor 22a and a second conveyor 22b. The first and the second conveyors 22a, 22b have a direction of transportation T which is perpendicular to the frangible lines 16 on the stacks 4.

As illustrated in figures 3a to 3c, the upper pressing member 18 is movable between a clearing position A, an immobilizing position B and a rupturing position C. In the clearing position A, the upper pressing member 18 is not in contact with the stack 4. The upper pressing member 18 is in the clearing position when the stack 4 is transported into the breaker module 8.

In the immobilizing position, the upper pressing member 18 applies pressure to an upper blank 3 in the stack 4. In this position, the first and second contact plates 19a, 19b are placed on each side of the frangible line 16. The upper pressing member 18 is moved downwardly in the vertical direction V and is contacting the upper blank 3 of the stack 4. The upper pressing member 18 is descended until a sufficient pressure is created in order to immobilize the stack 4. This means that the pressure is selected such that the distance between the conveyor 20 and the upper contact plates 19a, 19b corresponds to the sum of the thickness of the blanks 3 in the vertical direction V.

As illustrated in figure 3c, in the rupturing position C, the second pressing member 19b and the second conveyor 22b perform a rotary movement to rupture the frangible line 16.

The upper first and second contact plates 19a, 19b and the first and second conveyors 22a, 22b are vertically associated in their movement. A vertically aligned first contact plate 19a and a lower conveyor 22a are configured to perform a coordinated movement. The two vertically associated pairs of contact plates 19a, 19b and the lower conveyors 22a, 22b can be referred to as inlet side I and outlet side O, respectively.

When rupturing the frangible lines 16, the inlet side I remains in the immobilizing position B, while the outlet side O performs a pivoting movement of the second contact plate 19b and lower second conveyor 22b in unison. The pivoting movement results in a lateral movement of a second part 4b of the stack 4 in relation to a first part 4a of the stack 4. A lateral distance between the first and second conveyors 22a, 22b is thus increased as the first and second contact plates 19a, 19b and the first and second conveyors 22a, 22b move apart.

The breaker module 8 further comprises a control circuitry 46 comprising a memory 48 and controller 50. The memory 48 comprises displacement instructions for a conveyor motor 52 which is mechanically connected to the first and second conveyors 22a, 22b. The memory 48 also comprises instructions for a motor 53 of the upper pressing member 18 in order to move and position the upper pressing member 18 into the clearing position A, the immobilizing position B and the rupturing position C.

The breaker module 8 may further comprise an optical sensor 26 configured to detect the arrival of a front leading edge 5a of a stack 4 as it is transported into the breaker module 8. In such a way, the optical sensor 26 may send information to the control circuitry 46 such that the conveyor 22 is moved until the frangible line 16 is positioned in-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 instance, the sensor 26 can be located at the inlet of the breaker module 8. Alternatively, the optical sensor 26 can be located between the first and contact plates 19a, 19b of the upper pressing member 18.

As best seen in figures 4a to 4c, 5a and 5b, contact surfaces 30 of the first and second contact plates 19a, 19b are provided with an ejection mechanism 32. The ejection mechanism 32 is configured to release the upper blank 3 in the stack 4 when the upper pressing member 18 returns to the clearance position A. The ejection mechanism 32 thus ejects the upper blank 3 in the stack from the upper pressing member 18. This avoids that the upper blank 3 momentarily sticks to the upper pressing member 18 and becomes misaligned with the remaining stack 4.

The ejection mechanism 32 comprises a plurality of elongate ejection rods 34 which are received within slots 36 in the first and second contact plates 19a, 19b. The ejection rods 34 are movable in the vertical direction V.

The ejection rods 34 are movable between first position P1 where the ejection rods are fully received in the slots 36, and a second position P2 in which the ejection rods protrude from the contact surface 30. As the ejection rods 34 protrude from the slot 36, they are located 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 to the contact surface 31 of the ejection rods 34 at its most extended position P2. The protrusion distance dp can be between 6 and 30 mm. It is preferable with a protrusion distance dp of less than 50 mm.

The ejection rods 34 enter into the slots 36 when the pressing member 18 is pressed against the stack 4 of blanks 3. In such a way, the ejection rods 34 are flush with or vertically above the contact surface 30 of the pressing member 18. This reduces the risk that the ejection rods 34 create marks in the upper blank 3.

When the pressing member 18 is displaced vertically upwards and returns to the clearing position A, the ejection rods 34 move downwardly by gravity and eject the upper blank 3 from the upper pressing member 18. Each individual stack 4a, 4b can then be evacuated by the conveyor 20. The ejection rods 34 are attached to the contact plates by fasteners 38. The fasteners 38 comprise a rod 40 which is traversing the contact plates 30, and a stopper 42. The stopper 42 can be adjustable. Preferably, the stopper 42 is adjustable such as to adjust the vertical protrusion distance dp of the ejection rods 34. For instance, the stopper 42 can be a threaded nut. The required protrusion distance dp may be different depending on the area and weight of the blank 3. Typically, the smaller and heavier the blank 3 is, the smaller the protrusion distance dp needs to be.

The rod 40 may have one or several marks to define predetermined positions of the stopper 42. In an embodiment, the at least one mark may provide a haptic indication and guide the stopper 42 to its predefined position.

Each ejection rod 34 may be individually movable. Optionally, the ejection rods 34 on each contact plate 19a, 19b may be interconnected with each other. This allows the guiding of the ejection rods 34 such that they move on unison.

In an embodiment illustrated in figure 5a, the ejection rods 34 may extend in a perpendicular direction in relation to the frangible line 16. In other words, the longitudinal extension of the ejection rods 34 coincide with the direction of transportation T.

In another embodiment illustrated in figure 5b, the ejection rods 34 may extend obliquely and thus in a diagonal direction in relation to the frangible line 16. This ensures that the entire width of the stack 4 is in contact with at least one the ejection rod 34. Additionally, this prevents that the ejection rods 34 enter into the fluting of a blank 3 (made from corrugated cardboard), which may otherwise create a local deformation. Hence, the diagonal ejection rods 34 are configured to establish a simultaneous contact with several flutes in the blank 3, and in such a way they are configured to spread the contact pressure.

In a further embodiment and as illustrated in figure 5c, the ejection rods 34 may extend perpendicular to the direction of transportation T. Hence, the ejection rods 34 are parallel to the frangible line 16 on the blank 2. This may also prevent damage to the blank 2 as the fluting in corrugated cardboard often extends in the direction of transportation T. As illustrated in figure 6, the ejection rods 34 may be connected to ground (hence be “earthed”). To this effect, a wire 50 may connect to the ejection rods 34. The wire 50 may connect to the fasteners 38, or another protruding connection element which is connected to the ejection rods 34. The wire 50 may extend over the length of the contact plates 19a, 19b and connect to the chassis 24 The wire 50 may connect directly to the chassis 24, or connect indirectly to the chassis 24 via another mechanical component. As the chassis 24 is also earthed, it connects the wire 50 to earth.

Alternatively, the material of the ejection rods 34 may be selected such as they are less conductive than steel. In such a way, the ejection rods 34 are less prone to conduct electrostatic electricity. The material can for instance be an insulating material in the form of a coating.

By preventing the electrostatic energy, the upper blank 3 in the stack 4 can be prevented from adhering to the ejection rods 34.

Optionally, the slots 36 may have a bottom portion provided with a resilient layer. This may reduce the noise and wear on the upper pressing member 19 as the ejection rods 34 enter into the slots 36. Alternatively, a resilient layer is provided on the top surface of the ejection rods 34. The resilient layer may be connected to the ejection rods 34 with an adhesive. In such a way, the resilient layer can be changed with the ejection rods 34.

Claims

1 . A breaker module (8) for separating stacks (4) of juxtaposed blanks (3a, 3b) joined together by frangible lines (16), the breaker module comprising: a first conveyor (22a) and a second conveyor (22b) arranged one after the other in a direction of transportation (T) of the stack, an upper pressing member 18 which is mobile between a clearing position (A), an immobilizing position (B) and a rupturing position (C), wherein the upper pressing member (18) comprises a first contact plate (19a) and a second contact plate (19b), each contact plate having a contact surface (30) configured to contact an upper blank (3) in the stack, wherein each contact plate comprises an ejection mechanism (32), the ejection mechanism comprising a plurality of ejection rods (34) which are each received in a slot (36), and wherein the ejection rods are vertically movable so as to be received within the slots (36) when the pressing member (18) is in the immobilizing position (B) and rupturing position (C), and to protrude from the slots (36) and eject the upper blank (3) in the stack (4) when the pressing member (18) is moved into the clearing position (A).

2. The breaker module according to claim 1 , wherein the ejection rods protrude at a protrusion distance (dp) from the contact surface (30) of the upper pressing member (18) in the clearing position (A), and wherein the protrusion distance is between 5 and 50 mm.

3. The breaker module according to claim 1 or 2, wherein the ejection rods are connected to the contact plates (19a, 19b) by a fastener, the fastener comprising a connection rod (40) and a stopper (42).

4. The breaker module according to claim 3, wherein the stopper is displaceable along the rod such as to adjust the protrusion distance.

5. The breaker module according to any one of the preceding claims, wherein a longitudinal extension of the ejection rods coincides with the direction of transportation (T) of the stack (4).

6. The breaker module according to any one of claims 1 to 4, wherein a longitudinal extension of the ejection rods is perpendicular in relation to the direction of transportation (T).

7. The breaker module according to any one of claims 1 to 4, wherein a longitudinal extension of the ejection rods is oblique in relation to the direction of transportation (T) of the stack (4).

8. The breaker module according to any one of the preceding claims, wherein the ejection rods have a width (w1) which is smaller than the width (w2) of the slot, and preferably within the range of 70% to 95% of the slot.

9. The breaker module according to any one of the preceding claims, wherein a resilient layer is provided between the slots and the ejection rods.

10. The breaker module according to claim 9, wherein the resilient layer is connected to the ejection rods.

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

12. The breaker module according to any one of the preceding claims, further comprising an optical sensor (26) configured to detect the arrival of a front leading edge (5a) of the stack (4) and to provide a control signal to a control circuitry (46) of the breaker module, and wherein the control signal is configured to initiate a conveyor motor (52) to drive the conveyor (20) and a second motor (53) to move the upper pressing member (18) into the immobilizing position and the rupturing position.

13. A converting machine comprising a breaker module (8) according to any one of the preceding claims and a die-cutting module (6), the die-cutting module being arranged upstream of the breaker module in the direction of transportation, wherein the die-cutting module comprises at least one cutting tool configured to provide a frangible line (16) on a blank (3) such that the blank (3) comprises at least a first and a second juxtaposed blanks (3a, 3b) joined together by the frangible line.