ES2686072T3 - A corrugating device for sheets of paper material - Google Patents

Abstract

A method of corrugating sheets of paper material comprising the following steps: - providing two corrugation cylinders (21, 22) having work surfaces (21b, 22b) suitable for substantially reciprocally engaging to define a deformation zone (20a ) and for printing a deformation force on said sheets of paper material (10), - providing a movable pushing member (30) from a rest position where it is separated from the work surface (22b) of one of the two corrugation cylinders (22), to a working position to apply additional pressure to one of said corrugation cylinder (22), characterized in that the method further comprises the steps of: - moving the thrust member (30) to the working position for applying additional pressure to one of said corrugation cylinders (22) and increasing the deformation force applied on said sheets of paper material (10) if the thickness or of the paper material (10) is greater than a predetermined minimum thickness, and - processing said sheets of paper through said deformation zone (20a), after the pushing member (30) has moved in the position of work.

Description

DESCRIPTION

A corrugating device for sheets of paper material

[0001] The present invention relates to a corrugating device for sheets of paper material of the type

described in the preamble of claim 1.

[0002] In particular, the invention relates to a device in which a sheet of paper material, which is initially presented flat, undergoes a plastic deformation suitable to give it a corrugated profile to be used,

10 for example, to make corrugated cardboard. Currently, the corrugation devices known in the prior art are mainly composed of a calender that has two corrugation cylinders shaped in such a way that they plastically deform the sheets and thus give them a corrugated profile.

[0003] In particular, said corrugation cylinders have the corrugated outer surface suitably 15 to engage reciprocally and thereby define a work zone through which the sheets pass,

experiencing plastic deformation. The force necessary to deform the sheets is applied to the corrugation cylinders by means of pushing devices acting on the ends of said cylinders. The distribution of the necessary force, which will be applied uniformly throughout the mechanical free space of the machine, is carried out thanks to the inclination of one of the two cylinders, whose value is calculated to compensate for the elastic deformation of said corrugation cylinders. It follows that the force to deform the sheets can be a unique value, calculated in the design phase and related to the geometry and elasticity of the corrugation cylinders. US 6,012,501 describes how a labyrinth path in a single-sided corrugated line is substantially reduced, using a small diameter corrugation roller captured between a larger diameter conventional corrugation roller and a reinforcing roller arrangement . The smallest diameter corrugated roller 25 is captured to prevent bending under corrugated loads.

[0004] US 2003/054136 describes a corrugating unit, particularly for sheets or bands of paper, or the like, of the type comprising at least two rollers, having a serrated or corrugated surface, and which are mutually coupled and pressed against each other by a predetermined pressure or force. The

30 mutual compression between rollers is exerted over the entire axial length of the rolls. This can be obtained through mechanical or magnetic means.

[0005] US 2003/066590 describes a single-face corrugator of the type that uses a large diameter corrugation and joint roller and a small diameter corrugator roller that is operated without a drive

35 applied directly to any of the corrugating rollers. Instead, the arrangement of the pressure belt that supports the lower corrugated roller to provide the pressure force includes a series of driven support pressure belts that are loaded against the lower corrugated roller and that transmit the rotational movement thereto and through from the narrowing to the large diameter joint roller.

[0006] US 6,155,319 describes a unit for joining sheets of paper together in equipment

corrugated cardboard manufacturing comprising at least one serrated or corrugated roller, which is mounted in such a way that it rotates around its axis: means for feeding and pressing at least one sheet of flat paper, which interact with the serrated or corrugated laminating roller said flat sheet on the corrugated paper sheet transported by said serrated or corrugated roller and gluing means that apply adhesive on one of the sheets.

According to the invention, the means for feeding / pressing the flat sheet of paper against the sheet of corrugated paper on the serrated or corrugated roller consists of a roller that is mounted in such a way that it rotates around its axis and parallel to the dentate or corrugated and which is made, at least on its periphery, of a layer of natural or synthetic fibers or compacted mixtures thereof, which have a certain compressibility and / or deformability. The prior art described above has several significant drawbacks.

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[0007] A first significant drawback is represented by the limited adaptability of corrugated devices to sheets of different thicknesses and / or made of different materials.

[0008] In fact, in the case of processing a sheet having physicochemical characteristics different from the 55 hypotheses at the design stage, the corrugation cylinders discharge a force on the sheets that is not

suitable to deform them plastically.

[0009] For example, if the sheets have a greater mechanical resistance, the force applied by the cylinders is insufficient for their plastic deformation and, consequently, an elastic deformation occurs which

it reabsorbs practically immediately, once the force of the cylinders is eliminated. On the contrary, if the sheets have a lower mechanical resistance, the force applied causes the tearing of the sheets that determines a reduction in the quality of the board produced and, in some cases, a production stop with a relative increase in costs .

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[0010] Other problems can also be found in the case of processing sheets of a thickness

different from those for which they were designed; in this case too, the corrugation cylinders cannot perform the optimum deformation of the sheets.

10 [0011] In particular, such a problem is due to the fact that, due to the different thicknesses, the cylinders of

Corrugation apply to the sheets a different force than necessary and, consequently, they can perform a plastic deformation or tearing of the sheets. For such reasons, in the case where a company wishes to process sheets of paper material that have different characteristics, it is forced to buy a plurality of corrugation cylinders that have different dimensions from one another, or must accept the reduction of the characteristics 15 board mechanics, sometimes compensating for such with a greater amount of raw material.

[0012] In this situation, the technical object of the present invention is to develop a corrugation device

for sheets of paper material capable of substantially overcoming the above-mentioned drawbacks.

[0013] Within the sphere of said technical purpose, an important objective of the invention is to develop a

device that is capable of optimally processing even sheets having different characteristics from those planned without replacing rollers, corrugation cylinders or the like.

[0014] Another important objective of the invention is, therefore, to obtain a device capable of performing the correct plastic deformation of any type of sheet.

[0015] The technical object and the specific objectives are achieved by means of a corrugating device for sheets of paper material as claimed in the attached claim 1.

[0016] Preferred embodiments are described in the dependent claims.

[0017] The features and advantages of the invention are clearly apparent from the following detailed description of a preferred embodiment thereof, with reference to the accompanying drawings, in which:

Figure 1 shows the corrugating device for sheets of paper material according to the invention in a first working configuration; Y

Figure 2 shows the same corrugation device for sheets of paper material in a different configuration from that shown in Fig. 1.

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[0018] With reference to said drawings, reference number 1 indicates globally the corrugating device for sheets in paper material 1.

[0019] It comprises a frame capable of containing within it the various components, a calender 20, 45 including two corrugation cylinders, including those of different diameters, suitable for exerting a force of

deformation in the sheet of paper material 10, and at least one pushing member 30 capable of varying the deformation force exerted by the corrugating cylinders on the sheet 10.

[0020] The calender 20 comprises two cylinders preferably at least partially hollow to allow internal passage of a hot fluid (air and / or steam and / or heat transfer oil), with lightening openings. In

detail, includes a first corrugation cylinder 21 along which the material of the paper sheet 10 slides during processing and a second corrugation cylinder 22 suitable to engage with the first corrugation cylinder 21 defining an area of deformation 20a into which the material of the paper sheet 10 passes and simultaneously undergoes plastic deformation becoming a corrugated sheet.

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[0021] The first corrugation cylinder 21 and the second corrugation cylinder 22 are connected laterally to the frame so that during the advance of the sheets 10, they can rotate, in relation to the frame, around a first axis of rotation 21a and a second axis of rotation 22a, substantially parallel to each other.

[0022] These shafts are sized and / or connected by means of pins, bearings or other elements to allow slight bending thereof if they are subjected to predetermined mechanical forces.

[0023] In addition, the first 21 and the second corrugation cylinder 22 have suitably corrugated outer side surfaces 5 that respectively define the first work surface 21b and the second surface

of work 22b. In detail, the work surfaces 21b and 22b are corrugated and suitable for reciprocally coupling so that between them the aforementioned deformation zone 20a is substantially defined through which the sheet 10 passes and plastically deforms in a manner contrary to work surfaces 21b and 22b.

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[0024] To perform the correct deformation of the sheet 10, the corrugation device 1 has, in correspondence with at least one of the cylinders 21 and 22, at least one thrust member 30 suitable for varying the deformation force by applying a pressure additional to one of the work surfaces (21b, 22b). Preferably, the corrugation device 1 has at least two thrust members 30 placed one next to the

15 and suitable for applying the additional pressure to one of the work surfaces (21b, 22b) and, even more preferably, to the second work surface 22b.

[0025] The pushing member 30 is suitable for defining a resting position, shown in Figure 2, where the pushing member 30 does not discharge said additional pressure on the working surface 22b and

Consequently, the deformation force has a minimum value and at least one working configuration, which is shown in Figure 1, where an additional pressure is applied to the work surface 22b to increase the deformation force.

[0026] For this purpose, it comprises at least one pressure body 31 suitable for exerting additional pressure 25 on the work surface 22b, a support structure 32, suitable for supporting the pressure body 31, and

drive means 33 suitable for moving the support structure 32 and the pressure body 31 to allow the pushing member 30 to vary its configuration.

[0027] The pressure body 31 is suitable for pressing against the second work surface 22b to discharge the additional pressure on the second corrugation cylinder 22.

[0028] Therefore, it can be composed of a body with a shape opposite to the outer profile of the second corrugation cylinder 22 or, alternatively, by a belt or similar element suitable to deform, preferably elastically, to acquire a shape contrary to the outer profile previously mentioned.

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[0029] Preferably, the pressure body 31 is comprised of said belt capable of discharging the additional pressure on the surface 22b in an optimal manner.

[0030] The support structure 32 comprises one or more pairs of pulleys 32a, each of which is capable of allowing the pressure body 31 to move relative to the support structure 32, and a support 32b

capable of holding the pulleys 32a and therefore the pressure body 31 in the correct position.

[0031] In addition, it may comprise at least one stop element 32c capable of maintaining the pressure body 31 in the correct position.

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[0032] The pushing element 30, arranged on the side opposite the pressure body 31 in relation to the support structure 32, has the appropriate drive means 33 to allow it to vary its configuration.

[0033] In particular, the drive means 33 move the support structure 32 such that the pressure body 31 comes into contact with the work surface 22b substantially diametrically opposite to the

deformation zone 20a.

[0034] In this way, it is capable of exerting on the support structure 32 a force having a direction of action 33a substantially perpendicular to the deformation zone 20a, which is substantially perpendicular to

55 rotation axes 21a and 22a. Preferably, the force has an action direction 33a that extends substantially in a plane defined by axes 21a and 22a and substantially perpendicular to said axes of rotation 21a and 22a. The actuation means 33 therefore comprise a linear actuator suitable for applying the aforementioned force by means of a variation in the extent substantially parallel to the direction of action 33a. In particular, the drive means 33 comprise a series of pneumatic actuators or

Hydraulics suitable for varying its extension after a variation in internal pressure. Preferably, the drive means 33 comprise an inner tube provided with specific accessories for a power supply system which, by varying the internal pressure of the inner tube, causes an expansion thereof having a main extension direction substantially parallel to the direction of action 33.

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[0035] To allow the means of the unit 33 to correctly conduct the support structure 32, the thrust member 30 comprises a connection 34 suitable for weakly connecting the support structure 32 to the frame in order to guide the movement of the support structure 32 for the second corrugated cylinder 22, an interconnection apparatus 35, suitable for positioning between the drive means 33 and the support 32b

10 to allow a correct transfer of force between the aforementioned components and a wedge base 36 suitable for placing the second drive means 33 in an inclined position so that, as described above, the main direction of the extension is substantially parallel to the direction of action 33a.

[0036] The connection 34 preferably comprises a pin or other similar connection suitable for defining an axis of relative rotation 30a of the support structure 32 and therefore of the pressure body 31 in relation to the

second corrugation cylinder 22. Preferably, the relative rotation axis 30a is substantially parallel to the rotation axes 21a and 22 of the corrugation cylinders 21 and 22.

[0037] The interconnection apparatus 35 comprises a contact plate 35a placed between the drive means 33 and the support structure 32 and a kinematism suitable to allow the contact plate 35a

follow drive means 33 during configuration between the two rest and work settings.

[0038] In particular, the contact plate 35a is firmly connected to the actuation means 33 so that when the pushing member 30 passes from rest to the work configuration, it is installed on the support

25 32b, allowing the correct transfer of forces between the drive means 33 and the support 32b.

[0039] To provide the aforementioned movement of the plate 35a, the kinematism comprises a connecting element 35b connected to the contact plate and to the frame by means of two pins that allow the connecting element 35b to rotate both in relation to the frame as in relation to the contact plate 35a around

30 of rotation axes substantially parallel to the axis of relative rotation 30a.

[0040] The operation of the corrugation device according to the invention for sheets of paper material, described above in the structural sense, is as follows: initially the device 1 has the pushing member 30 in the rest position, that is, with the pressure body 31 suitably separated from the surface of

35 work 22b so that the additional pressure is not discharged in the second corrugation cylinder 22, and therefore the deformation force is at its minimum value.

[0041] During processing, depending on the characteristics of the sheets of paper material 10 to be processed, the operator adjusts the device 1 to achieve the desired deformation force.

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[0042] In particular, if the sheets of paper material 10 have a minimum thickness, practically the same as that estimated during the design stage of the corrugated cylinders, the required deformation force is minimal and, consequently, the device 1 it is activated leaving the pushing member 30 in the resting position.

[0043] Vice versa, if the thickness of the sheets of paper material 10 is greater than the minimum thickness before

mentioned and, therefore, the required deformation force is greater, the operator activates the passage of the thrust member 30 from the rest to the working position to apply the additional pressure to the second corrugation cylinder 22 and thus increase the force of deformation.

50 [0044] In detail, the drive means 33 expand along the direction of action 33a

causing the support structure 32 to rotate around the axis of relative rotation 30a and the pressure bodies 31 sit on the second work surface on the side opposite the deformation zone 20a.

[0045] Once the pressure bodies 31 and the work surface 22b are touched, the means of

Drive 33 continues to expand along said direction of action 33a so that the pressure bodies 31 are tensioned and begin to discharge additional pressure on the second work surface 22b resulting substantially perpendicular to the deformation zone 20a and, preferably , on the plane defined by the two rotation axes 21a and 22a.

[0046] Due to the additional pressure, the axis of rotation 22 and / or the second corrugation cylinder 22 begins to deform and / or flex by determining elastically, in correspondence with the deformation zone 20a, a reduction in the distance between the work surfaces 21b and 22b and thus, an increase in the deformation force suffered by the paper sheet material 10 when it crosses said deformation zone 20a.

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[0047] A minimum deformation or bending of the second axis of rotation 22a and / or of the second corrugation cylinder 22 is sufficient to achieve a significant variation in the pressure on the sheet of paper material 10. Therefore, the bending can be a consequence of both the size of the corrugating cylinders and the rotation axes, and the type of connection thereof.

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[0048] Once the deformation force has reached the desired value, the operator stops the expansion of the drive means 33 blocking the thrust member 30 in the reached position, and then the processing of the blade 10 begins.

[0049] The invention, as can be seen from the operation described above, allows a new

corrugation process of sheets in paper material.

[0050] Such a corrugation process preferably comprises a stage of calibration of the deformation force during the processing of the sheet of paper material 10.

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[0051] In particular, at the calibration stage, an additional pressure is applied to the second corrugation cylinder 22 by means of the pushing member 30 which, proving to be substantially parallel to the direction of action 33a, drags the second work surface 22b towards the first work surface 21b and thus the deformation force varies, as described above.

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[0052] The invention achieves some important advantages.

[0053] A first important advantage lies in the extreme reliability of the corrugation device 1 of the sheets of paper material 10 which have different thicknesses and / or are made of different materials of those

30 for which the corrugation cylinders 21 and 22 were designed.

[0054] Such an advantage is achieved thanks to the innovative thrust member 30 which, by exerting additional pressure on the contact surface 22b, determines an increase in the deformation force.

[0055] Another important advantage lies in the fact that the corrugating device 1 can be adapted to

sheets of paper material 10 of varying thicknesses in a fast and practical manner, and therefore without the need for expensive and time-consuming calibration operations.

[0056] In fact, the device 1, while having corrugation cylinders 21 and 22 designed to process sheets 40 of paper material 10 of a minimum thickness, can also process sheets 10 of greater thickness, increasing the

deformation force thanks to the thrust members 30.

[0057] Another advantage is, therefore, the fact that the device 1, which is capable of adapting to various types of paper sheet material 10, minimizes the number of corrugation cylinders needed.

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[0058] Another advantage of no less importance is the greater production capacity of the device 1 thanks to a significantly shorter calibration time compared to prior art devices.

[0059] All elements as described and claimed herein can be replaced by 50 equivalent elements and the scope of the invention includes all other details, materials, shapes and

dimensions.

Claims (5)

1. A method of corrugating sheets of paper material comprising the following steps: 5 - providing two corrugation cylinders (21, 22) having work surfaces (21b, 22b) suitable for substantially reciprocally engaging to define a deformation zone (20a) and for printing a deformation force on said sheets of paper material (10), - providing a movable thrust member (30) from a rest position where it is separated from the work surface (22b) of one of the two corrugation cylinders (22), 10 to a working position to apply an additional pressure to one of said corrugation cylinder (22), characterized in that the method further comprises the steps of: - moving the pushing member (30) to the working position to apply additional pressure to one of said corrugating cylinders (22) and increasing the deformation force applied on said sheets of paper material (10) if the thickness of the paper material (10) is greater than a predetermined minimum thickness, and 15 - processing said sheets of paper through said deformation zone (20a), after the pushing member (30) has moved in the working position. 2. A method according to claim 1, characterized in that the predetermined minimum thickness is estimated during a design stage of the corrugation cylinders (21, 22). twenty 3. A method according to claim 2, further comprising the step of: - elastically deforming and / or flexing one of said corrugation cylinders (22) through the additional pressure applied by the pushing member (30), therefore - reduce the distance between the work surfaces (21 b, 22b) of the two corrugation cylinders 25 (21, 22). 4. A method according to claim 3, further comprising the step of: - stop the movement of the pushing member (30) when the deformation force applied on said sheets of paper material (10) has reached a predetermined desired value by blocking the pushing member (30) in the 30 position reached. 5. A method according to claim 4, characterized in that the desired predetermined strain value is estimated during a design stage of the corrugation cylinders (21, 22). A method according to any of the preceding claims, further comprising: - a step of calibrating the deformation force during the processing of the sheet of paper material (10), applying an additional pressure to one of said corrugation cylinders (22) by means of the pushing member (30) and thus varying deformation force 40