Device for rupturing attachment zones on folding boxes and production unit comprising such a rupture device

This severing device (1) includes an upper pressing member (2), a pile support part (4) having a plurality of conveying members (10) for conveying the pile in a conveying direction (X), a lower pressing member (6) arranged under the conveying members (10). The conveying members (10) are juxtaposed in a transverse direction. Two juxtaposed conveying members can be parted. The lower pressing member (6) has: i) two adjacent lower plates (6.1, 6.2) that can be moved apart, and ii) a lower translation actuator (6.3) for moving the lower plates (6.1, 6.2) so as to cause the severance slot (2.0) between juxtaposed conveying members to coincide with a frangible line in the plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. §§ 371 national phase conversion of PCT/EP2017/025078, filed Apr. 5, 2017, which claims priority of French Patent Application No. 16 53390, filed Apr. 18, 2016, the contents of which are incorporated by reference herein. The PCT International Application was published in the French language.

TECHNICAL FIELD

The present invention relates to a severing device for severing attachment zones defining frangible lines on stacked sheets of cardboard.

The present invention applies to the field of the manufacture of collapsible boxes made from sheets of cardboard. A collapsible box may for example be a packing case. In general, such sheets of cardboard are precut when stacked. The precutting produces on each sheet of cardboard a frangible line defined by attachment zones.

Prior Art

The document FR 2527189 describes a severing device for severing attachment zones defining frangible lines on stacked sheets of cardboard forming a pile. The severing device of FR 2527189 comprises:an upper pressing member which is mobile between an immobilizing position, in which it immobilizes the pile, and a clear position, in which it is distant from the pile; anda lower part configured to support and convey the pile when the upper pressing member is in the immobilizing position.

The lower part comprises a conveyor including a multitude of rollers configured to move the pile in the conveying direction.

However, because each roller needs to be relatively narrow, the pressure of the pile on the rollers carries the risk of causing deep marks at least on the underside of the pile. Because of these marks, at least the bottom sheet of each pile exhibits a quality defect that requires it to be scrapped, thereby increasing the level of waste and the production cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to solve the aforementioned problems, completely or in part.

To this end, one subject of the present invention is a severing device, for severing attachment zones defining frangible lines on stacked sheets of cardboard forming a pile, the severing device comprising at least:an upper pressing member which is mobile at least between:an immobilizing position, in which the upper pressing member applies pressure to the top sheet of the pile, so as to immobilize the pile, anda clear position, in which the upper pressing member is arranged in such a way as to be distant from the top sheet of the pile; anda support part configured to support the pile when the upper pressing member is in the immobilizing position, the support part comprising a plurality of conveying members configured to convey and move the pile in a conveying direction,

the severing device comprising:the conveying members are juxtaposed in a transverse direction which extends transversely to the conveying direction, the conveying members are configured in such a way that two juxtaposed conveying members are movable relative to one another in the transverse direction, several conveying members each include: i) a belt extending parallel to the conveying direction and configured to drive the pile in the conveying direction, ii) at least one rotary pinion configured to drive the belt in a belt circuit, anda lower pressing member arranged under the conveying members, and the conveying members being mobile at least between:an immobilizing position, in which the lower pressing member applies pressure to the undersides of the conveying members so that the conveying members immobilize the pile, anda clear position, in which the lower pressing member is arranged in such a way as to be distant from the undersides of the conveying members;

the lower pressing member comprising:

i) two adjacent lower plates that can be moved apart in the transverse direction so as to define a severance slot, and

ii) a lower translation actuator arranged to move the lower plates in translation in the transverse direction, so as to cause the severance slot to coincide with a frangible line.

Thus, such a severing device allows the frangible lines to be severed at different positions in the transverse direction without marking the bottom sheet of the pile. This is because the belts of the conveying members are relatively broad, and this spreads the pressure of the lower pressing member over a relatively large area and therefore minimizes the risk of marking the bottom sheet of the pile.

According to an alternative, several conveying members each have an elongate shape with a ratio of width to length less than 10%, or even less than 5%. This elongate shape is, for example, rectilinear and rectangular.

According to an alternative form, the transverse direction is orthogonal to the conveying direction. Thus, such lower pressing members make it possible to sever attachment zones that form rectilinear frangible lines. The conveying direction may be horizontal when the severing device is in the service configuration.

According to an alternative form, the lower translation actuator comprises a rack mechanism and rack rails.

According to an alternative form, the lower ram is a linear actuator, for example a ram. The linear actuator may be moved by electrical, pneumatic or hydraulic power.

The belt conveying members allow piles to be conveyed effectively into the severing device and allow the attachment zones to be severed along the frangible lines.

According to an alternative form, each conveying member includes such a belt and at least one such rotary pinion.

According to an alternative form, conveying members each comprise two rotary pinions situated respectively at the two ends of the conveying member in the conveying direction.

As an alternative to this embodiment, several conveying members may, instead of belts, comprise series of wheels or series of rollers configured to drive the pile in the conveying direction.

According to one embodiment, the number of conveying members is greater than eight, preferably greater than sixteen.

According to one embodiment, each conveying member is movable in the transverse direction with respect to a juxtaposed conveying member.

Thus, such a severing device allows a great many frangible lines to be severed at different positions in the transverse direction, thereby simplifying the conveying of the pile upstream of the severing device and avoiding the need to reposition in a single severing zone a pile that has several frangible lines.

According to one embodiment, several conveying members each have a width comprised between 50 mm and 500 mm, preferably between 50 mm and 200 mm, measured in the transverse direction.

Thus, such widths allows numerous conveying members to be juxtaposed, so as to define numerous severing zones, and therefore so as to be able to sever numerous frangible lines.

In other words, each of these conveying members is narrow in comparison with the conveying members of the prior art.

According to one embodiment, the upper pressing member is mobile, between its immobilizing position and its clear position, in a substantially vertical direction when the severing device is in the service configuration,

and the conveying members are mobile, between the immobilizing positions and the clear positions, in a substantially vertical direction when the severing device is in the service configuration.

For the upper pressing member, the clear position is situated above the immobilizing position, whereas for the lower pressing member, the clear position is situated below the immobilizing position.

According to one embodiment, the upper pressing member comprises a pivoting part, the severing device further comprising a pivoting actuator configured to drive the pivoting part about a direction of pivoting parallel to the transverse direction, so as to sever attachment zones defining frangible columns in the sheets of cardboard of the pile, the frangible columns extending transversely to the frangible lines.

Thus, such a severing device allows attachment zones to be severed in two perpendicular directions, along the frangible lines and frangible columns.

According to one embodiment, the upper pressing member comprises at least two adjacent upper plates that can be moved apart in the transverse direction so as to define a severance slot, the severing device further comprising an upper translation actuator designed to move the upper pressing member translationally in the transverse direction so as to cause the severance slot to coincide with a frangible line.

Thus, such adjacent plates may effectively apply pressure to the top sheet of the pile.

According to one embodiment, the upper pressing member comprises an upper ram configured to move the two upper plates apart and closer together in the transverse direction,

and in which the lower pressing member comprises a lower ram configured to move the two lower plates apart and closer together in the transverse direction.

According to one embodiment, several conveying members each further include: coupling elements which are arranged on each of the transverse faces of the rotary pinion and which are configured to collaborate with coupling elements of the juxtaposed conveying member, the severing device further comprising a rotary actuator configured to drive the rotation of the rotary pinions.

According to an alternative form, the coupling elements comprise dog clutches or friction disks.

According to one embodiment, the severing device further comprises a clutch system configured to move the conveying members translationally closer together in the transverse direction.

According to one embodiment, the clutch system further comprises at least:

i) one guide rail extending in the transverse direction,

ii) carriages designed to move on the at least one guide rail, each carriage being configured to support a respective conveying member, and

iii) at least one electromechanical clutch configured to move a conveying member so as to move the carriages along the at least one rail.

According to one embodiment, the at least one electromechanical clutch comprises a pivoting bar designed to pivot so as to cause the conveying member to move horizontally in the transverse direction.

Moreover, another subject of the present invention is a manufacturing plant for manufacturing collapsible boxes, the manufacturing plant t comprises:

i) a severing device according to the invention, and

ii) a control unit configured so as to:receive a signal indicating the position of at least one incoming frangible line in the transverse direction,command the upper pressing member to move from the clear position into the immobilizing position, so as to immobilize the pile,command the conveying members to move from the clear positions into the immobilizing positions, so as to immobilize the pile, andpart the upper plates and the lower plates in the transverse direction so as to sever the attachment zones defining the at least one frangible line.

The embodiments and alternative forms mentioned hereinabove may be considered in isolation or in any technically feasible combination.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 to 11illustrate a severing device1for severing attachment zones defining frangible lines101on stacked sheets of cardboard forming a pile100, visible inFIG. 12. In general, a sheet of cardboard has the overall shape of a rectangle and a pile100of stacked sheets of cardboard has the overall shape of a rectangular parallelepiped, as shown inFIG. 12.

The severing device1comprises an upper pressing member2, a lower pressing member6and a support part4. The severing device1further comprises a chassis5configured to support the upper pressing member2, the lower pressing member6and the support part4and other components of the severing device1.

When the severing device1is in the service configuration, the upper pressing member2is higher up than the lower pressing member6and the support part4is situated between the upper pressing member2and the lower pressing member6. When the severing device1is in the service configuration (FIG. 1), the upper pressing member2is higher up in the immobilizing position than in the clear position.

The upper pressing member2is mobile between:an immobilizing position, in which the upper pressing member2applies pressure to the top sheet of the pile, so as to immobilize the pile, anda clear position in which the upper pressing member2is arranged in such a way as to be distant from the top sheet of the pile.

In the example of the figures, the upper pressing member2is mobile, between its immobilizing position and its clear position, in a substantially vertical direction Z when the severing device1is in the service configuration (FIGS. 1 and 2).

The support part4is configured to support the pile when the upper pressing member2is in the immobilizing position. The support part4comprises a plurality of conveying members10. In the example of the figures, the number of conveying members10is equal to 36.

The conveying members10are configured to convey and move the pile100in a conveying direction X. To this end, each conveying member10includes:

i) a belt12which extends parallel to the conveying direction X and is configured to drive the pile in the conveying direction X, and

ii) rotary pinions14and15configured to drive the belt12in a belt circuit; the rotary pinions are situated respectively at the two ends of the conveying member10in the conveying direction X.

The conveying members10are juxtaposed in a transverse direction Y which extends transversely to the conveying direction X. The transverse direction Y here is orthogonal to the conveying direction X. The conveying direction X is horizontal when the severing device1is in the service configuration (FIGS. 1 and 2). The conveying direction X is usually referred to as the “running direction” and the transverse direction Y is usually referred to as the “weft direction”.

The conveying members10are configured so that two juxtaposed conveying members10are movable relative to one another in the transverse direction Y. In the example of the figures, each conveying member is movable in the transverse direction Y with respect to a juxtaposed conveying member10.

Each conveying member10here has a width W10approximately equal to 50 mm, measured in the transverse direction Y. In addition, each conveying member10here has an elongate shape with a ratio of width W10to length L10approximately equal to 3.5%. The length L10is approximately equal to 1450 mm. The elongate shape of each conveying member10here is rectilinear and rectangular.

AsFIG. 3shows, the upper pressing member2comprises two adjacent upper plates2.1,2.2that can be moved apart in the transverse direction Y so as to define a severance slot2.0. The upper pressing member2comprises an upper ram26configured to selectively move the two upper plates2.1and2.2apart and closer together in the transverse direction Y.

FIG. 1symbolically illustrates a manufacturing plant51for manufacturing collapsible boxes. The manufacturing plant51comprises: i) the severing device1and ii) a control unit52configured to control several components of the severing device1.

When the severing device1has to sever frangible lines101, the upper ram26moves the upper plate2.1away from the upper plate2.2. The upper ram26then moves the upper plate2.1closer to the upper plate2.2, to return to the adjacent position. The movements of the upper ram26are controlled by the control unit52.

The severing device1further comprises an upper translation actuator24which is arranged to move the upper pressing member2, namely the upper plates2.1and2.2, in translation in the transverse direction Y. When the severing device1is in service, the upper translation actuator24moves the upper pressing member2so as to cause the severance slot2.0to coincide with a frangible line101. The movements of the upper translation actuator24are controlled by the control unit52.

The lower pressing member6is arranged underneath the conveying members10. The conveying members10are mobile between:an immobilizing position, in which the lower pressing member6applies pressure to the undersides of the conveying members10, so that the conveying members10immobilize the pile100, anda clear position, in which the lower pressing member6is arranged in such a way as to be distant from the undersides of the conveying members10.

The conveying members10are mobile, between the immobilizing positions and the clear positions, in the substantially vertical direction Z when the severing device1is in the service configuration (FIGS. 1 and 2).

In the clear position, the belts12of the conveying members10can turn and advance, and therefore move the piles100in the conveying direction X. In the immobilizing position, the belts12cannot turn or advance, because they are in contact with the lower pressing member6.

The severing device comprises a vertical drive system27which is configured to raise and lower the conveying members10in the vertical direction Z. The vertical drive system27comprises: i) vertical link rods27.1, ii) disks27.2and iii) synchronizing link rods27.3.

The vertical link rods27.1are secured to a frame27.4which supports the conveying members10. The vertical link rods27.1are four in number here, two of them visible inFIG. 3.

Each disk27.2acts as a cam because it converts a rotational movement into a translational movement. Each vertical link rod27.1is connected to a respective disk27.2excentrically. Each synchronizing link rod27.3is connected excentrically to a respective disk27.2.

The vertical drive system27further comprises transverse actuators, not depicted, which are configured to move the synchronizing link rods27.3translationally parallel to the transverse direction Y.

In service, the transverse actuators move the synchronizing link rods27.3; the synchronizing link rods27.3turn the disks27.2; the disks27.2drive the vertical link rods27.1either upward or downward.

When the vertical link rods27.1are in the clear (up) position, the conveying members10are clear of the lower pressing member6, such that the belts12can convey the piles10in the conveying direction X.

The lower pressing member6comprises two lower plates6.1and6.2. The lower plates6.1and6.2are adjacent and can be moved apart in the transverse direction Y so as to define a severance slot2.0.

The lower pressing member6further comprises a lower translation actuator6.3which is arranged to move the lower plates6.1and6.2in translation in the transverse direction Y. In the example ofFIGS. 8 and 9, the lower translation actuator6.3is made up of a rack mechanism comprising rack rails6.30.

When the severing device1is in service, the lower translation actuator6.3moves the lower pressing member6so as to cause the severance slot2.0to coincide with a frangible line101. The movements of the lower translation actuator6.3are controlled by the control unit52.

In addition, the lower pressing member6comprises a lower ram6.6, symbolized inFIGS. 8 and 9, configured to move the two lower plates6.1and6.2apart and closer together, selectively, in the transverse direction Y.

When the severing device1is to sever frangible lines101, the lower ram6.6moves the lower plate6.1away from the lower plate6.2. The lower ram6.6then moves the lower plate6.1closer to the lower plate6.2, to return to the adjacent position. The movements of the lower ram6.6are controlled by the control unit52.

Moreover, each conveying member10further includes coupling elements16and17. The coupling elements16and17are arranged on each of the transverse faces of the rotary pinions14and15. The coupling elements16and17are configured to collaborate with coupling elements of the juxtaposed conveying member10. The severing device1further comprises a rotary actuator, not depicted, configured to drive the rotation of the rotary pinions14and15.

The severing device1further comprises a clutch system30which is configured to move the juxtaposed conveying members10closer together translationally in the transverse direction Y. The clutch system30“re-engages” or re-couples the respective rotary pinions14and15with the respective coupling elements16and17.

The clutch system30thus allows the conveying members10to be returned to the initial position after the lower plates6.1and6.2have parted the conveying members10so as to sever a frangible line in the pile100of stacked sheets of cardboard. When the conveying members10are in the initial position, all their rotary pinions14and15are engaged with the coupling elements16and17, allowing all the belts12to be turned simultaneously.

The clutch system30comprises:

i) two guide rails32running parallel to the transverse direction Y,

ii) carriages34designed to slide respectively along the guide rails32, each carriage34being configured to support a respective conveying member10,

iii) two electromechanical clutches38configured to move the carriages34along the rails32.

In the example ofFIGS. 10 and 11, each electromechanical clutch38comprises a pivoting bar38.1the ends of which are fitted with rollers. The clutch system30further comprises a vertical linear actuator31which is designed to move one end of the pivoting bar38.1in translation parallel to the vertical direction Z.

A first end of the pivoting bar38.1is in contact with the vertical linear actuator31. The other end of the pivoting bar38.1is in contact with the first conveying member10(on the left inFIGS. 10 and 11).

The pivoting bar38.1is designed here to pivot through an angle A38.1approximately equal to 30 degrees, thereby causing the first conveying member10to move horizontally by approximately 15 mm to the right in the transverse direction Y.

When the severing device1and the manufacturing plant51are in service, the control unit52notably performs the following steps:

receiving a signal indicating the position of at least one incoming frangible line in the transverse direction Y,commanding the upper pressing member2to move from the clear position to the immobilizing position, so as to immobilize the pile,commanding the conveying members10to move from the clear positions to the immobilizing positions, so as to immobilize the pile, andparting the upper plates2.1,2.2and the lower plates6.1and6.2in the transverse direction Y, so as to sever the attachment zones that define the at least one frangible line101.

Next, the control unit52notably performs the following step: commanding the vertical linear actuators31so as to move the conveying members10translationally in the transverse direction Y. In the case of the two conveying members10that had previously been parted, the rotary pinions14and15respectively re-engage with the coupling elements16and17. Thus, the severing device1is once again ready to sever a frangible line101.

Of course, the present invention is not restricted to the particular embodiments described in the present patent application, or to embodiments within the competence of a person skilled in the art. Other embodiments may be envisioned without departing from the scope of the invention, on the basis of any element equivalent to an element indicated in the present patent application.