EP2585258B1 - Supporting device for a workstation of a profiling machine - Google Patents

Description

The present invention relates to a device making it possible to hold sheet-shaped elements when these are introduced one by one into a work station fitted to a shaping machine.

The invention finds a particularly advantageous, but not exclusive, application in the field of the manufacture of cardboard packaging.

The state of the art is represented for example by the documents US2004 / 0245711 and EP1935820 .

It is known to cut out poses in a succession of sheets by means of a shaping machine commonly called a cutting press. In this type of machine, each sheet is successively introduced into a cutting station inside which the actual cutting operation is carried out, then into an ejection station where the removal of the waste generated in the previous step.

In such a waste ejection station, each sheet is introduced individually in a pre-cut form. The poses are indeed cut out but still attached to each other by means of attachment points. The same is true for many portions of leaves which have no final use, and which are therefore considered waste.

When a cut sheet decelerates in the ejection station, before coming to a stop between the ejection tools, its rear part naturally tends to catch up with its front part which is held by the gripper bar. This phenomenon is particularly sensitive when the leaves are relatively light and / or large.

Anyway, this has the effect of significantly deforming the flatness of the sheet, which increases the risk of offset relative to the tools. Now we know that the ejection operation requires precision in the prior positioning of the sheet; said precision being of course all the greater as the waste has small dimensions.

To remedy this difficulty, it has been thought to maintain each cut sheet during its introduction into the ejection station, by partially retaining it by its rear part. For this, systems have in particular been developed that generate local aspiration at one side of the sheet. We are thinking here in particular of a Bernoulli tablet placed transversely at the entrance to the ejection station.

However, this type of arrangement has the drawback of offering insufficient efficiency with sheets of low grammage, in particular with those weighing less than 400 g. Indeed, as soon as the sheet is too light, its rear part tends to float during movement and thus find itself relatively distant from the Bernoulli tablet. The latter cannot therefore properly fulfill its suction function.

In the end, this makes the positioning of the sheet more than approximate, and therefore it generates inaccuracy when ejecting the waste. But the lack of effectiveness of the Bernoulli tablet also causes clicks at the rear part of the sheet. As a result, many attachment points tend to break, which becomes problematic when ejecting the waste and often forces the operator of the forming machine to lower the rate.

Also, the technical problem to be solved by the object of the present invention is to provide a device for holding a sheet-shaped element during its phase of introduction into a work station of a shaping machine, said holding device comprising a suction member capable of partially retaining each sheet by its rear part during the phase of introducing said sheet into said work station, holding device which would make it possible to avoid the problems of the state of the technique by notably offering a significantly improved efficiency.

The solution to the technical problem posed consists, according to the present invention, in that the holding device further comprises blower means capable of pressing the rear part of each sheet against the suction member during the phase of introduction.

It is understood that throughout this text, the term sheet designates very generally any sheet-shaped element, such as for example a sheet of paper, compact cardboard, corrugated cardboard, plastic material, etc.

Be that as it may, the principle of the invention therefore consists in combining the action of a suction member with that of a blower. Schematically, the air flow generated by the blower presses on one side of the sheet, which makes it possible to press the other side against the suction member and therefore guarantee full efficiency for the latter.

The invention as thus defined has the advantage of generating effective retention of the sheets in the work station, regardless of their grammage and / or format. This ultimately allows the shaping machine to operate at high speed.

The present invention further relates to the characteristics which will emerge during the description which follows, and which should be considered in isolation or according to all their possible technical combinations.

• La figure 1 illustre une machine de façonnage dans laquelle est intégrée une station d'éjection de déchets qui est équipée d'un dispositif de maintien conforme à l'invention.
• La figure 2 montre en détail l'entrée de la station d'éjection de déchets, au moment où une feuille s'apprête a y être introduite.
• La figure 3 est une vue sensiblement analogue à la figure 2, mais avec la feuille en fin de phase d'introduction dans la station d'éjection de déchets.

This description, given by way of nonlimiting example, is intended to better understand what the invention consists of and how it can be implemented. The description is also given with reference to the accompanying drawings in which:

• The figure 1 illustrates a shaping machine in which is integrated a waste ejection station which is equipped with a holding device according to the invention.
• The figure 2 shows in detail the entrance to the waste ejection station, when a sheet is about to be inserted.
• The figure 3 is a view substantially similar to the figure 2 , but with the sheet at the end of the phase of introduction into the waste ejection station.

For reasons of clarity, the same elements have been designated by identical references. Likewise, only the essential elements for understanding the invention have been shown, and this without respecting the scale and schematically.

The figure 1 represents a shaping machine 1 making it possible to cut out poses in a succession of sheets of cardboard 10. These poses are intended to be subsequently folded and glued to form packaging boxes.

In this particular embodiment, chosen only by way of example, the shaping machine 1 is conventionally composed of several work stations 100, 200, 300, 400, 500 which are juxtaposed, but interdependent one by one to form a set unitary. There is thus an introduction station 100, a cutting station 200, a waste ejection station 300, a reception station 400 with separation of the blanks, and a discharge station 500 for the residual waste. We also observe the presence of means of transport 600 which are responsible for individually moving each sheet 10 from the output of the introduction station 100 to the discharge station 500.

It should be noted that out of all Figures 1 to 3 , the different workstations 100, 200, 300, 400, 500 have been shown in an extremely schematic manner. Each of them is in fact materialized by two rectangles respectively symbolizing its upper part and its lower part; parts which are positioned on either side of the sheet movement plane 10.

Conventionally, the introduction station 100 mainly comprises a feeder and a margin table, and it is fed with sheets of cardboard 10 from a stack stored on a pallet. The feeder is more particularly responsible for removing the sheets 10 from the top of the stack one by one and sending them successively to the directly adjacent margin table. At the margin table, the sheets 10 are laid in a tablecloth, that is to say placed one after the other so as to be partially overlap. The whole of the sheet is driven in displacement along a plate by means of a conveyor belt system, in the direction of the cutting station 200. At the end of the sheet, the head sheet 10 is systematically positioned with precision by means of a tracking system commonly called a register. Since such an introduction station 100 is perfectly known from the state of the art, it will not be described further here. This is also the reason why these various components have not been shown in detail in the figures.

The cutting station 200 is in the conventional form of a platen press which, in this embodiment, implements an upper fixed base on the underside of which is joined a cutting tool, and a movable lower base on the upper face of which the delivery counterparts are fixed.

The work station located just after the cutting station 200 is the ejection station 300. The latter has the function of removing the waste which is directly produced during the cutting of the sheets 10. We are thinking here in particular of waste zones central, as well as rear and side bands. Anyway, this operation is carried out here conventionally thanks to the cooperation of three elements, namely an upper ejection tool, a central ejection board and a lower ejection tool.

Downstream of the ejection station 300, there is the reception station 400 whose main function consists in breaking the attachment points between the poses by means of a male upper tool and a tool lower female. The objective is twofold, namely to separate the poses from each other, and to constitute stacks of poses capable of being subsequently worked by folder-gluers.

The process for processing the sheets 10 in the shaping machine 1 ends in the discharge station 500 where the residual waste is discharged. This is released automatically, then evacuated from the evacuation station 500 by a mat.

The shaping machine 1 has means of transport 600 making it possible to individually move each sheet 10 from the outlet of the introduction station 100 to the discharge station 500.

Here again very conventionally, the means of transport 600 use a series of gripper bars 610 which are mounted movable in transverse translation by means of two chains of chains 620 arranged laterally on each side of the shaping machine 1. Each chain train 620 runs through a loop which allows the gripper bars 610 to follow a trajectory passing successively through the cutting station 200, the ejection station 300, the reception station 400 and the evacuation station 500.

Concretely, each gripper bar 610 performs a forward path in a substantially horizontal passage plane between a drive wheel 630 and a deflection wheel 640, then a return path in the upper part of the shaping machine 1. Once brought back to the level of the drive wheel 630, each gripper bar 610 is then able to grasp a new sheet 10.

As can be seen more clearly at figure 2 , each clamp bar 610 consists of a transverse bar 611 on which is mounted a plurality of clamps 612 which are designed to be able to grip the front edge of the same sheet 10 simultaneously. Each clamp bar 610 is coupled to the two chain trains 620 via the two ends of its transverse bar 611.

The Figures 1 to 3 show that the ejection station 300 is moreover provided with a device 310 for holding each sheet 10 during its introduction phase. This holding device 310 comprises a suction member 320 which is responsible for partially retaining each sheet 10 by its rear part, during its phase of introduction into the ejection station 300. Concretely, the suction member 320 maintains the rear part of the sheet 10 without immobilizing it, allowing it to slide gradually as it moves in accordance with the figure 3 .

In the present case, the suction member 320 is in the form of a Bernoulli tablet 321, that is to say a device provided with several suction holes at each of which a vacuum is created individually. by Venturi effect. This type of organ being known in itself it will not be described further here, both structurally and functionally. Anyway, the Bernoulli 321 tablet is located transversely at the entrance to the ejection station 300, at the lower part of said station so as to be positioned under the plane of movement of the sheets 10, and thus being able to act on the underside of the latter.

In accordance with the object of the present invention, the holding device 310 is further provided with blower means 330 which are able to press the rear part of each sheet 10 against the suction member 320 during the phase of introduction.

In fact, the blower means 330 are capable of generating an air flow on each sheet 10 entering the ejection station 300, at the face of said sheet 10 which is opposite to the member. 320. As a first step, the air flow will tend to push the sheet 10 towards the suction member 320, until it brings a portion of the latter into effective contact with said member. suction 320. But in a second step, the air flow will exert pressure on the rear part of the sheet 10, which will naturally tend to press it against the suction member 320.

According to a feature of the invention, the blower means 330 are capable of generating an air flow over a part of the sheet 10, which is located upstream of the suction member 320 relative to the direction of movement of said sheet 10 in the ejection station 300. It is understood here that the air flow is likely to exert pressure on any part of sheet 10 which has not yet passed the suction member 320, including including the portion of said sheet 10 which is placed directly in line with said suction member 320.

According to another feature of the invention, the blower means 330 are able to generate an air flow as close as possible to the plane of movement of the sheets 10 in the ejection station 300. Such proximity makes it possible to maximize the pressure exercised by the air flow for a given blower power, or to minimize the dimensioning of the blower for an equivalent result.

In a particularly advantageous manner, the blower means 330 are capable of generating an air flow over substantially the entire width of each sheet 10 entering the ejection station 300. This characteristic responds to the fact that generally, the suction member 320 is dimensioned to act also on the entire width of the sheets 10.

According to another advantageous characteristic, the blower means 330 are capable of generating a substantially planar air flow in a direction which is coplanar with the direction of movement of the sheets 10 in the ejection station 300. The fact that the flow air is substantially planar means that it is somehow in the form of an air curtain, that is to say a substantially laminar flow whose section has a width much greater than its height . The fact that the air flow is projected in a direction coplanar with the direction of movement of the sheets 10, meanwhile mean that the plane in which it propagates intersects the plane of movement of the sheets 10 along a straight line which is substantially orthogonal to the direction of movement of said sheets 10 in the ejection station 300.

According to another feature of the invention, the blower means 330 are able to generate an air flow in a direction which is inclined relative to normal to the plane of movement of the sheets 10, and which is directed in one direction substantially opposite to the direction of movement of said sheets 10 in the ejection station 300. The main objective here is to guarantee perfect spreading of the sheet 10, thanks to the fact that the pressure exerted by the air flow takes place in a direction substantially opposite to the direction of displacement of said sheet 10.

That said, such an arrangement also proves to be advantageous when the sheet 10 has not yet arrived at the right of the blower means 330 but is still in the cutting station 200 placed directly upstream. In such a situation, in fact, the air flow coming from the blower means 330 will propagate at least partially under the sheet 10. By venturi effect, this will create a depression which will tend to pull said sheet 10 downwards. , thereby facilitating the detachment of the poses from the platen press.

Preferably, the blower means 330 are capable of generating an air flow with an angle of incidence of 30 to 50 °, relative to the plane of movement of the sheets 10 in the ejection station 300.

In accordance with a currently preferred embodiment of the invention, since it is perfectly suited to shaping machines 1 operating at very high speeds, the blower means 330 operate here continuously. That said, it is of course possible to provide a more or less discontinuous mode of operation of the blower means 330.

Similarly, the blower means 330 operate here at constant power, but it is perfectly conceivable to operate the blower means 330 with a variable power level.

In this preferred embodiment, the blower means 330 are also disengageable. This characteristic gives versatility to the forming machine 1 as a whole. It in fact offers the possibility of operating the holding device 310 without the blower means 330. This constitutes a solution particularly suited to low speeds and / or to the work of relatively rigid sheets.

As can be seen more clearly in figures 2 and 3 , the blower means 330 comprise at least one nozzle 331 provided with a slot-shaped outlet orifice; the latter being oriented parallel to the plane of movement of the sheets 10 in the ejection station 300. In practice, two scenarios will mainly arise. Either the blower means 330 will only use one single nozzle 331 acting over substantially the entire width of the sheet 10, or they will have a plurality of jets 331 juxtaposed to cover substantially the entire width of the sheet 10.

In the example of realization of Figures 1 to 3 , each sheet 10 being introduced into the ejection station 300 via a clamp bar 610 carrying a plurality of clamps 612, the blower means 330 comprise several nozzles 331 positioned transversely offset from the trajectories of respective displacement of the different pliers 612 of the pliers bar 610. Such an arrangement prevents directing the air flow directly against the pliers 612, and therefore avoids creating unnecessary turbulence capable of reducing the efficiency of the blower means 330 .

Of course, the invention also relates to any work station 200, 300, 400 intended to equip a shaping machine 1, and having a device for maintenance 310 as previously described. We are thinking here in particular of a waste ejection station 300 as in the particular embodiment chosen to illustrate the invention, but also of a cutting station 200 or a reception station 400 with separation of poses.

But even more generally, the invention also relates to any shaping machine 1 equipped with at least one such work station 200, 300, 400.

In the embodiment, the holding device 310 is fully integrated at the ejection station 300, that is to say including the blower means 330 which thus form an integral part of the work station. The fact remains that in the case where the shaping machine 1 comprises a first work station 300 equipped with a holding device 310 as previously described, as well as a second work station 200 placed directly upstream of the first work station 300, it is perfectly conceivable to mount the suction member 320 in the first work station 300, and to mount the blower means 330 at the level of the second work station 200.

Claims (14)

1. Moulding machine (1) comprising a workstation (300) including a device for holding (310) a sheet-shaped element (10) during the introduction phase thereof in the workstation (300), said holding device (310) comprising a suctioning member (320) able to partially retain each sheet (10) by the rear portion thereof during the phase of introducing said sheet (10) in said workstation (300), characterised in that the holding device (310) further includes blowing means (330) capable of flattening the rear portion of each sheet (10) against the suctioning member (320) during the introduction phase.
2. Moulding machine (1) according to claim 1, characterised in that the blowing means (330) are capable of generating an airflow on each sheet (10) being introduced in the workstation (300), on the face of said sheet (10) which is opposite the suctioning member (320).
3. Moulding machine (1) according to one of claims 1 or 2, characterised in that the blowing means (330) are capable of generating an airflow over a portion of the sheet (10), which is situated upstream of the suctioning member (320) with respect to the movement direction of said sheet (10) in the workstation (300).
4. Moulding machine (1) according to any one of claims 1 to 3, characterised in that the blowing means (330) are capable of generating an airflow as close as possible to the movement plane of the sheets (10) in the workstation (300).
5. Moulding machine (1) according to any one of claims 1 to 4, characterised in that the blowing means (330) are capable of generating an airflow over substantially all of the width of each sheet (10) being introduced in the workstation (300).
6. Moulding machine (1) according to any one of claims 1 to 5, characterised in that the blowing means (330) are capable of generating an airflow substantially flat in a direction which is coplanar to the movement direction of the sheets (10) in the workstation (300).
7. Moulding machine (1) according to any one of claims 1 to 6, characterised in that the blowing means (330) are capable of generating an airflow in a direction which is inclined with respect to the normal to the movement plane of the sheets (10), and which is directed in a direction substantially opposite the movement direction of said sheets (10) in the workstation (300).
8. Moulding machine (1) according to claim 7, characterised in that the blowing means (330) are capable of generating an airflow with an angle of incidence of 30 to 50°, with respect to the movement plane of the sheets (10) in the workstation (300).
9. Moulding machine (1) according to any one of claims 1 to 8, characterised in that the blowing means (330) are capable of operating continuously.
10. Moulding machine (1) according to any one of claims 1 to 9, characterised in that the blowing means (330) are capable of operating at a constant power.
11. Moulding machine (1) according to any one of claims 1 to 10, characterised in that the blowing means (330) are disengaged.
12. Moulding machine (1) according to any one of claims 1 to 11, characterised in that the blowing means (330) include at least one nozzle (331) equipped with a slot-shaped outlet orifice; said slot being oriented parallel to the movement plane of the sheets (10) in the workstation (300).
13. Moulding machine (1) according to any one of claims 1 to 12, characterised in that each sheet (10) being introduced in the workstation (300) by way of a clamping bar (610) carrying a plurality of clamps (612), the blowing means (330) including several nozzles (331) positioned transversally offset with respect to the respective movement paths of the different clamps (612) of the clamping bar (610).
14. Moulding machine (1) according to any one of claims 1 to 13, comprising a second workstation (200) placed directly upstream of the first workstation (300), characterised in that the suctioning member (320) is integral with the first workstation (300), and in that the blowing means (330) are integral with the second workstation (200).

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