Single facer for manufacturing corrugated board with a system for controlling an extruding member

Abstract

The single-face corrugating machine (1) includes a carrying frame (3) and a pivoting structure pivotally connected to the carrying frame (3) about a pivot axis (29). The pivoting structure includes a first pivoting arm (23) located on a first side of the single-face corrugating machine (1) and a second pivoting arm (25) located on a second side of the single-face corrugating machine (1). The pivoting structure supports two guide rollers (32, 35) of a continuous flexible member (31), and the continuous flexible member applies pressure to the corrugating roller (17). An actuator system (75, 77) controls the traction force and position of the continuous flexible member (31).

Description

Technical Field

[0001] The present invention relates to a machine for manufacturing corrugated cardboard. More specifically, the present invention relates to an improvement of a corrugating machine or a so-called "single facer". Background Art

[0002] Corrugated cardboard is manufactured starting from a smooth paper web unwound from a suitable reel. In its simplest form, corrugated cardboard consists of a smooth paper web and a corrugated paper web bonded together along the wave crests of the corrugated paper web. Usually, a second smooth paper web needs to be added to this basic structure, which is adhered to the corrugated paper web so that the latter is sandwiched between two smooth paper webs, also called liners. In some cases, other structures with a series of corrugated paper webs between the smooth paper webs are also added to this structure consisting of three paper webs.

[0003] Single facer corrugated cardboard is produced by a "single facer" which includes a pair of intermeshing corrugating rolls, between which a first smooth paper web is fed. The first smooth paper web is thermally deformed into the nip between the two corrugating rolls and it becomes a grooved paper web. An adhesive is applied to the groove crests of the grooved paper web adhered to one of the corrugating rolls, and the smooth paper web is pressed and heated onto the grooved paper web provided with the adhesive.

[0004] There is provided an extrusion unit including at least one extrusion member pressing against one of the corrugating rolls for bonding the grooved paper web and the smooth paper web to each other. The smooth paper web and the grooved paper web pass between the corrugating roll and the extrusion member.

[0005] In some single facers, the extrusion unit includes a continuous flexible member in the form of a belt which is driven around guide rolls. This type of single facer is disclosed in US9,545,769, EP0698752, US10,293,588, US2015 / 0122423, US5,512,020, EP2805810, EP2792477, US5,951,817, US2014 / 0345804, EP0850753, JP10-710, JP2001-38830, JP10-709.

[0006] US2,638,962 discloses a corrugating machine including an extrusion belt driven around two guide rolls, wherein the first guide roll is rotatable relative to the bearing structure about a fixed axis, and the second guide roll can move with the rotation movement of the fixed axis of the first guide roll. When the belt moves away from the corrugating roll, it presses against an outer drum that keeps the belt stretched.

[0007] JP11105172 discloses a corrugating machine having an extrusion belt driven around three rollers. A complex actuator system drives the movement of two belt guide rollers to control the traction of the belt and maintain the correct guidance of the belt.

[0008] Another corrugating machine is disclosed in JP2962660, which has an extrusion belt and members for controlling the stretching and guiding of the belt. Also in this case, the belt is guided by a complex system consisting of three guide rollers and associated actuators for controlling their movement.

[0009] EP3556548 discloses a single - facer corrugating machine with a mechanism for replacing the corrugating roll. The single - facer corrugating machine also includes a pair of fixed - axis guide rollers around which the extrusion belt is driven. When the corrugating roll is removed from the single - facer corrugating machine, the extrusion belt is lifted.

[0010] Since continuous flexible members must withstand very high operating temperatures and operating traction forces, they are complex and costly machine elements. They are prone to wear and must be replaced regularly. The replacement causes machine downtime. The replacement operation must be carried out carefully by trained personnel so as not to damage the new continuous flexible member installed in the old position.

[0011] When manufacturing various types of corrugated board, the corrugating roll needs to be replaced due to the different groove shapes and sizes of the grooved paper web. In modern single - facer corrugating machines, two meshing corrugating rolls are installed in a roll box or a roll cylinder to simplify this operation. A plurality of roll boxes or roll cylinders contain pairs of different corrugating rolls for manufacturing different corrugated boards. The roll cylinder replacement is quick and simple. However, it may encounter obstacles when there is an extrusion unit. Replacing the corrugating roll requires removing the corrugating roll in the single - facer corrugating machine from the extruder. This operation requires complex mechanical solutions. For example, a single - facer corrugating machine with a system provided with a roll cylinder or a roll box for replacing the corrugating roll is disclosed in US2007 / 0084565.

[0012] In addition, using a continuous flexible member in the form of a belt requires careful control of its traction force and its position during operation. This requires the use of complex control and guidance systems.

[0013] Therefore, in this field, there is a continuous search for simpler and more effective construction solutions aimed at facilitating and simplifying one or more of the above - mentioned operations. Summary of the Invention

[0014] According to one aspect, there is provided a single - facer for manufacturing single - facer corrugated board, which includes a carrying frame, and a first corrugating roll and a second corrugating roll meshing with each other are accommodated in the carrying frame. The single - facer further includes a pivoting structure, which is pivotally connected to the carrying frame about a pivot axis, and includes a first pivoting arm located on a first side of the single - facer and a second pivoting arm located on a second side of the single - facer.

[0015] The pivoting structure is part of a pressing unit or assembly, that is, provided with a continuous flexible member, which applies pressure to one of the corrugating rolls.

[0016] The pressing unit or assembly includes: a first guide roll having a first rotation axis, which is supported by a corresponding first support on the first pivoting arm and by a corresponding second support on the second pivoting arm; and a second guide roll having a second rotation axis, which is supported to the first pivoting arm by a corresponding first support and to the second pivoting arm by a corresponding second support. The pressing unit further includes a continuous flexible member, such as a belt, which is guided around the first guide roll and the second guide roll.

[0017] The single - facer further includes a control system, which can rotate the pivoting structure about the pivot axis to position it in a working position and a raised position. In the working position, the continuous flexible member is pressed against the corrugating roll, and in the raised position, the first guide roll and the second guide roll are spaced apart from the second corrugating roll.

[0018] In order to control and maintain the continuous flexible member in the correct position and traction force, the single - facer includes adjusting means, which in turn includes: a first actuator, which is associated with the first pivoting arm and can adjust the distance between the first support of the first guide roll and the first support of the second guide roll; and a second actuator, which is associated with the second pivoting arm and can adjust the distance between the second support of the first guide roll and the second support of the second guide roll. The first actuator and the second actuator can be actuated independently of each other. The adjusting means further includes a third actuator on one of the pivoting arms, which can adjust the position of the corresponding support of one of the guide rolls in a transverse direction relative to the adjusting direction of the corresponding first actuator or second actuator.

[0019] The two actuators adjust the traction force of the continuous flexible member, and the set of three actuators allows correction of the slipping and / or twisting movement of the continuous flexible member.

[0020] The pivot structure allows the extrusion assembly or unit to be easily moved from the working position to a position spaced apart from the corrugating roll, for example to replace the corrugating roll and / or replace the continuous flexible member. The arrangement of the three actuators carried by the pivot structure provides an effective arrangement for controlling and regulating the continuous flexible member.

[0021] Further advantageous features and embodiments of the single-sided corrugating machine, in particular of the extrusion unit or assembly and associated components for adjusting the traction force and the position of the continuous flexible element, will be defined in the appended dependent claims, which form part of this specification.

[0022] According to another aspect, there is disclosed herein a single-sided corrugating machine for manufacturing single-sided corrugated board, comprising: a carrying frame; a first corrugating roll and a second corrugating roll that can be mounted in the carrying frame, which mesh with each other and are mounted in the carrying frame. The single-sided corrugating machine further comprises an extrusion unit that is adapted to press against the second corrugating roll. The extrusion unit includes a first guide roll pivotally supported about a first axis of rotation and a second guide roll pivotally supported about a second axis of rotation. A continuous flexible member is guided around the guide rolls.

[0023] Characterized in that the first guide roll and the second guide roll are supported by a pivot structure that is pivotally connected to the carrying frame about a pivot axis that is substantially parallel to the axes of the first corrugating roll and the second corrugating roll. The pivot structure is associated with a control system adapted to rotate the pivot structure to a working position and a raised position, wherein in the working position the continuous flexible member is pressed against the second corrugating roll, and in the raised position the first guide roll and the second guide roll are spaced apart from the second corrugating roll.

[0024] The single-sided corrugating machine may include, in a combined manner, other features described herein, in particular one or more features defined in the appended claims. Description of the Drawings

[0025] The invention will become more apparent from the description and the drawings, which illustrate embodiments by way of non-limiting examples. More specifically, in the drawings:

[0026] Figure 1 A side view of the single-sided corrugating machine in the working position is shown;

[0027] Figure 2 It is shown Figure 1 of the single-sided corrugating machine from the opposite side with respect to Figure 1 seen in a side view;

[0028] Figure 2A A very simplified cross-sectional view of the single-sided corrugating machine according to the intermediate vertical plane between the two sides is shown;

[0029] Figure 2B Shows a cross-sectional view of a single-face corrugating machine in the position shown in accordance with the intermediate vertical plane between the two sides; Figure 1 and Figure 2 the position shown;

[0030] Figure 3 Shows a side view similar to Figure 1 where the extrusion unit is lifted;

[0031] Figure 4 Shows a side view similar to Figure 2 where the extrusion unit is lifted;

[0032] Figure 5 Shows a cross-sectional view of a single-face corrugating machine in the position shown in accordance with the intermediate vertical plane between the two sides of the single-face corrugating machine; Figure 3 and Figure 4 the position shown;

[0033] Figure 6 Shows a view similar to Figure 3 where the roller box of the corrugating roll is removed;

[0034] Figure 7 Shows a view similar to Figure 4 where the roller box of the corrugating roll is removed;

[0035] Figure 8 Shows a cross-sectional view of the intermediate vertical plane of the single-face corrugating machine according to Figure 7 ;

[0036] Figure 9 Shows an enlarged view of the details of Figure 8 where some parts are removed;

[0037] Figure 10 Shows a side view similar to Figure 6 where the extrusion unit is lowered;

[0038] Figure 11 Shows a side view similar to Figure 7 where the extrusion unit is lowered;

[0039] Figure 12 Shows a side view similar to the view of Figure 11 where the actuator of the extrusion unit is in a separated state from the corresponding pivot arm;

[0040] Figure 13 Shows an isometric view of the single-face corrugating machine in the Figure 12 position where the continuous flexible member is partially withdrawn from the guide roller;

[0041] Figure 14 Shows according to Figure 12View of a single - facer along line XIV - XIV;

[0042] Figure 15 and 16 shows Figure 14 an enlarged view of the details indicated by XV and XVI in;

[0043] Figure 17 shows a top view of the extrusion unit;

[0044] Figure 18 shows according to Figure 17 view XVIII - XVIII;

[0045] Figure 19 shows according to Figure 17 view XIX - XIX;

[0046] Figure 20 shows according to Figure 17 cross - sectional view XX - XX;

[0047] Figure 21 shows according to Figure 19 cross - sectional view XXI - XXI;

[0048] Figure 22 shows according to Figure 19 cross - sectional view XXII - XXII;

[0049] Figure 23 shows a partial isometric view of the extrusion unit on the side where a motor for actuating a continuous flexible member is installed;

[0050] Figure 24A and 24B shows a partial isometric view of the extrusion unit 21, showing a sensor for detecting the position of the continuous flexible member 31;

[0051] Figure 25A 、 25B shows two schematic side views of the extrusion unit, illustrating the movement of one of the two guide rollers of the continuous flexible member to adjust its tension;

[0052] Figure 26 and Figure 27 shows two schematic views of the extrusion unit, illustrating the movement of one of the guide rollers of the continuous flexible member to correct its twist; and

[0053] Figure 28A 、 28B shows two schematic views of the extrusion unit, illustrating the movement of one of the two guide rollers of the continuous flexible member to correct its twist. Detailed Description

[0054] The overall structure of the single-sided corrugating machine 1 can be understood with reference to Figure 1 and 2 2A, where the first two figures show side views of the single-sided corrugating machine seen from two opposite sides, while Figure 2A shows a very simplified cross-sectional view according to the intermediate vertical plane between the two sides, where only the main components of the single-sided corrugating machine 1 are shown. Figure 2B shows a cross-sectional view according to the intermediate vertical plane between the two sides of the single-sided corrugating machine.

[0055] The single-sided corrugating machine 1 includes: a carrying frame 3 on which a corrugating roll is supported; and an extrusion unit for pressing two paper webs for forming a single-sided corrugated board (not shown in the figure) against each other. The carrying frame includes a first side wall 5 on the first side of the single-sided corrugating machine 1 and a second side wall 7 on the second side of the single-sided corrugating machine 1. Also refer specifically to Figure 14 and 17 . The two side walls 5 and 7 are joined to each other by cross beams 9, 11, as specifically shown in Figure 13 and 14 , where the corrugating rolls of the single-sided corrugating machine 1 are removed. Generally, the first side is the side where the drive device is located, and the second side is the operator side, that is, the side where the operator can usually access the single-sided corrugating machine 1.

[0056] A roll box or roll cylinder 13 including a first corrugating roll 15 and a second corrugating roll 17 stacked on the first corrugating roll is inserted into the carrying frame 3. The roll cylinder 13 is replaceable, that is, interchangeable, to change the characteristics of the corrugated web produced by the single-sided corrugating machine 1 using different corrugating rolls 15, 17.

[0057] The roll box 13 is supported in the carrying frame 3 of the single-sided corrugating machine 1 by means of two forming support profiles 13.1 and 13.2, which cooperate with complementary support profiles 3.1 and 3.2, and these complementary support profiles 3.1 and 3.2 are integrated with the carrying frame 3. The roll box is inserted into the single-sided corrugating machine 1 on the side of the single-sided corrugating machine 3 (usually on the side defined by the second side wall 7). Insertion on the opposite side or both sides cannot be excluded.

[0058] Advantageously, the roll box 13 is inserted into the carrying frame 3 and supported on the support profiles 3.1, 3.2, where due to the weight of the roll box and the corrugating rolls 15, 17 and due to the thrust of the extrusion unit, the roll box 13 remains stationary, which will also be described below.

[0059] The corrugating rolls 15, 17 are known per se and will not be described in detail. Each of them has a corrugated cylindrical surface, and the two grooved cylindrical surfaces engage with each other at the corrugating nip defined between the two corrugating rolls 15, 17. The first smooth paper web passes through the corrugating nip and is formed into a corrugated shape due to the pressure applied by the two corrugating rolls.

[0060] The first corrugating roll 15 acts in conjunction with an adhesive applicator 16 shown only in Figure 2A a simplified cross-section, and the adhesive applicator 16 applies adhesive to the groove ridges formed on the first paper web (while still adhering to the second corrugating roll 17) before applying the adhesive to the second smooth paper web. In order to bond the two paper webs, one being grooved and the other being smooth, the single-face corrugating machine 1 includes a pressing unit or assembly 21 which is arranged to act on the upper part of the second corrugating roll 17 around which the two paper webs are guided, from top to bottom.

[0061] The pressing unit or assembly 21 includes a pivoting structure which in turn includes a first pivoting arm 23 located on the first side of the carrying frame 3 and a second pivoting arm 25 located on the second side of the carrying frame 3. The two pivoting arms 23, 25 can be rigidly connected to each other, for example, by means of a cross beam 27. In the illustrated embodiment, the two pivoting arms 23, 25 are hinged to the carrying frame 3 about a pivoting axis 29 which is parallel to the axes of the corrugating rolls 15, 17 when the corrugating rolls 15, 17 are installed in the single-face corrugating machine 1.

[0062] The pressing unit or assembly 21 further includes a continuous flexible member 31, such as a continuous belt. The continuous flexible member 31 is guided around a first guide roll 32 so as to rotate around a first rotation axis 33, and is guided around a second guide roll 35 so as to rotate around a second rotation axis 37. The guide rolls 32, 35 and the corresponding rotation axes 33, 37 and the continuous flexible member 21 are specifically shown in Figure 5 and Figure 8 a cross-sectional view.

[0063] The overall operation of the single-face corrugating machine can be easily referred to Figure 2AIt is understood with reference to the simplified cross-section. The first smooth paper web N1 is guided around the heated roller 20 and fed into the corrugating nip between the first corrugating roller 15 and the second corrugating roller 17, where it is permanently deformed to form grooves parallel to the rotational axes of the corrugating rollers 15, 17. The first paper web N1 remains adhered to the second corrugating roller 17 and receives the adhesive applied by the adhesive applicator 16 on the thus formed grooves. Downstream of the adhesive applicator 16, the first corrugated web N1 is guided by the second corrugating roller 17 below the pressing unit 21 and more precisely between the corrugated surface of the second corrugating roller 17 and the continuous flexible member 31, and the continuous flexible member 31 acts on the second corrugating roller 17. The second smooth paper web N2 is guided around the heated roller 22 and fed between the first grooved paper web N1 adhered to the second corrugating roller 17 and the pressing unit 21, and more precisely below the continuous flexible member 31 of the pressing unit 21. The pressure applied to the two webs N1, N2 in the nip between the pressing unit 21 and the second corrugating roller 17 causes the webs N1, N2 to adhere to each other. At the exit of the single-face corrugating machine 1, a single-face corrugated cardboard web SF is obtained, the structure of which is visible in the enlarged view shown in Figure 2A The adhesive C that bonds the grooved web N1 to the smooth web N2 is shown.

[0064] The first guide roller 32 and the second guide roller 35 define the first branch of the continuous flexible member 31, which includes the part of the continuous flexible member 31 between the two guide rollers 32, 35 that faces the second corrugating roller 17. The first branch of the continuous flexible member 31 constitutes the active branch, i.e., the branch that presses against the second corrugating roller 17. The second branch or return branch of the continuous flexible member 31 is defined again between the guide rollers 32, 35 on the opposite side (i.e., opposite to the second corrugating roller 17).

[0065] The gear motor 39 that provides rotational movement to the second guide roller 35 and thus to the continuous flexible member 31 is mounted on the first pivot arm 5, while the first guide roller 32 is mounted idly on the pivot arms 23, 25.

[0066] In other embodiments not shown, the gear motor 39 is not provided, and both the guide rollers 32 and 35 are mounted idly on the pivot structure. In this case, the movement of the continuous flexible member can be provided by the friction of the second corrugating roller 17.

[0067] The first pivot arm 23 is constrained to a first linear actuator 41, such as a cylinder-piston actuator, preferably of the hydraulic type. One end 41.1 of the linear actuator 41 is pivotally connected to the support frame 3, while the second end 41.2 of the linear actuator 41 is pivotally connected to the first pivot arm 25. Arranged on the opposite side of the single-face corrugating machine 1 is a second linear actuator 43, which constrains the second pivot arm 25 to the support frame 3. One end 43.1 of the linear actuator 43 is pivotally connected to the support frame 3, while the second end 43.2 of the linear actuator 43 is pivotally connected to the second pivot arm 25. The two linear actuators 41, 43 control the pivotal movement of the pivotal structure including the pivot arms 23, 25 and the cross beam 27 about the pivotal axis 29 to perform the operations described below.

[0068] Further details of the extrusion unit 21 will be described below. Specifically, it will be described from the following aspects: details regarding the mutual connection between the pivot arms 23, 25 and the support frame 3 and details facilitating the replacement of the continuous flexible member 31; details regarding the system facilitating the replacement of the roller box or the roller; and details regarding the system controlling the traction force and keeping the continuous flexible member 31 guided. It can be clearly seen from this specification that the combination of features regarding these three functions of the single-face corrugating machine 1 is in the illustrated embodiment. However, they can be used separately from each other. For example, the feature facilitating the replacement of the corrugating roller can be used in the single-face corrugating machine 1, which has a different system for replacing the continuous flexible member and / or a different system for controlling the traction force and keeping the continuous flexible member guided. Similarly, the features and elements for facilitating the replacement of the continuous flexible member can be used together with a different system for facilitating the replacement of the corrugating roller and / or a different system for controlling the traction force and keeping the continuous flexible member guided. Similarly, the latter can also be used in a single-face corrugating machine having a different system for changing the corrugating roller and / or for replacing the continuous flexible member.

[0069] Before describing the foregoing aspects in more detail, reference is made here Figures 1 to 7 Described is the movement performed by the single-face corrugating machine 1, more precisely the movement performed by the extrusion assembly or unit 21, for removing the roller box 13 of the corrugating rollers 15, 17. Figure 1 and 2 Shows side views of the first side and the second side of the single-face corrugating machine 1 having the roller box or the roller 13 and the corresponding corrugating rollers 15, 17. The extrusion unit 21 is in the working position, i.e., in the lower position. In this position, the continuous flexible member 31 is pressed against the upper part of the second corrugating roller 17 (i.e., the corrugating roller arranged at a higher level in the roller box 13 resting on the support frame 3). In this working position, the actuators 41, 43 push the extrusion unit 21 downward. In the illustrated embodiment, each of the pivot arms 23, 25 has supports 23A and 25A. The two supports 23A, 25A are arranged to cooperate with the support 13A carried by the roller 13. The supports 23A, 25A are specifically atFigure 2 , 4 , 5, 7. One of the supports 13A is specifically visible in Figure 2 .

[0070] When the single - facer 1 is in the working position, the pivot arms 23, 25 assume an angular position defined by the rest of the supports 23A, 25A of the pivot arms on the supports 13A of the roller box 13, and the supports 13A of the roller box 13 in turn rest on the support profiles 3.1, 3.2. The pressure applied by the actuators 41, 43 holds the pivot arms 23, 25 in place and helps to keep the roller box 13 of the corrugating rollers 15, 17 in the correct position.

[0071] A tensile actuator as described below applies a traction force to the continuous flexible member 31 when the extrusion unit 21 is in the working position, so as to keep the continuous flexible member 31 adhered to a paper web (not shown) interposed between the continuous flexible member 31 and the second corrugating roller 17. The traction force of the continuous flexible member reduces the thrust applied by the actuators 41, 43 on the support 13A.

[0072] To replace the roller box 13, first the extrusion unit 21 is rotated upwards with a rotational movement about the pivot axis 29. By this movement, the extrusion unit 21 is brought to a raised position spaced apart from the roller box 13. The lower branch of the continuous flexible member 31, i.e., the branch facing the second corrugating roller 17, is held in traction between the first guide roller 32 and the second guide roller 35 by a mechanism to be described below.

[0073] The raised position of the extrusion unit 21 and thus the raised position of the pivot structure and the guide rollers 32, 35 carried thereon are shown in Figure 3 (the first side of the single - facer 1) and 4 (the second side of the single - facer 1) in two side views, and in Figure 5 a sectional view.

[0074] Arranging the pivot axis 29 of the pivot structure at a distance from both the rotational axes 33, 37 of the first guide roller 32 and the second guide roller 35 allows for a greater spacing between the guide rollers and the second corrugating roller 17, thus facilitating the removal of the roller box 13.

[0075] By providing the extrusion unit 21 with a lifting and lowering movement about the pivot axis 29, an extremely simple and reliable system can be obtained for performing the various operations required for a single - facer, in particular: keeping the continuous flexible member 31 under the pressure of the second corrugating roller 17 during the production of corrugated board; the operation of replacing the roller box 13; the operation of replacing the continuous flexible member 31.

[0076] When the pivoting structure is in the raised position, the roller box 13 can be lifted from the support profiles 3.1 and 3.2 and removed from the single facer 1. In the illustrated embodiment, the roller box 13 can preferably be removed by taking it out from the second side of the single facer 1, but the possibility of removing it from the first side of the single facer 1 cannot be excluded. Figure 6 , 7 Figures 8 show a side view and a cross-sectional view of the single facer 1 after the roller box 13 has been removed.

[0077] After removing the roller box 13, it can be replaced with a roller box 13 having different corrugating rollers 15, 17, thereby manufacturing another type of corrugated board.

[0078] As Figure 1 , Figure 2 and Figure 3 clearly show, when the pivoting structure including the first pivoting arm 23, the second arm 25 and the crossbeam 27 moves away from the second corrugating roller 17, the continuous flexible member 31 tends to loosen, and its first branch facing the second corrugating roller 17 tends to rest on the second corrugating roller 17. When removing the roller box 13, the first branch (lower branch) of the continuous flexible member 31 will hang downwards, at least partially occupying the space where the new roller box 13 is to be inserted. If the operator inserting the new roller box 13 does not pay sufficient attention and does not care about manually lifting the first branch of the continuous flexible member 31, this may damage the continuous flexible member 31.

[0079] Given that it is designed to withstand extreme working conditions, both in terms of traction and working temperature, the continuous flexible member 31 is a very expensive machine element. In fact, the corrugating rollers are heated to accelerate the mutual adhesion between the paper webs forming the corrugated board, and the continuous flexible member 31 is subjected to a very high traction force, thereby exerting a very high pressure on the second corrugating roller 17, again accelerating the adhesion of the paper webs forming the corrugated board.

[0080] In the illustrated embodiment, in order to avoid the risk of damaging the continuous flexible member 31 during the replacement of the roller cylinder 13, the pressing unit or assembly 21 includes a stretching device, which is generally indicated by the reference numeral 51 and is specifically visible in Figure 8 and 9 .

[0081] In the illustrated embodiment, the stretching device 51 includes a stretching rod 53 which is arranged in a closed path defined by a continuous flexible member 31. The stretching rod 53 extends substantially parallel to the pivot axis 29 and is carried by the pivot structure. Accordingly, the stretching rod participates in the pivoting movement of the pivot structure about the pivot axis 29. When the pressing unit 21 is in the working position, the stretching rod 53 is in the non-working position, preferably not in contact with the continuous flexible member 31 or, in any case, not exerting any significant force thereon. For this purpose, the stretching rod 53 can be received in the space between the first guide roller 32 and the second guide roller 35.

[0082] When the pivot structure is lifted from the working position ( Figure 1 、 2 ) to the raised position ( Figure 3 、 4 、5), the stretching rod 53 is lifted together with the pivot structure while it performs a movement relative to the first guide roller 32 and the second guide roller 35, thereby pushing the second branch of the continuous flexible member 31 from the inside, which second branch faces the opposite side of the second corrugating roller 17. Figure 8 and 9 show the final position occupied by the stretching rod 53 once the pivot structure has been brought to its fully raised position. The stretching rod 53 of the stretching device 51 pushes the return branch of the continuous flexible member 31 outwards, deforming it and preventing the flexible member from loosening towards the first branch of the second corrugating roller 17. Basically, the first branch of the continuous flexible member 31 remains stretched between the first guide roller 32 and the second guide roller 35. The traction force applied to the continuous flexible member 31 is negligible. It is sufficient to prevent the first branch of the continuous flexible member 31 from sagging downwards.

[0083] In some embodiments not shown, the movement of the stretching rod can be driven by an actuator which is carried by the pivot structure including the pivot arms 23, 25 and the cross beam 27. However, in order to obtain a safer operation while making the structure simpler and thus reducing costs, it is advantageous to provide that the stretching device 51 is passively activated when the pivot structure is brought to the raised position.

[0084] For this purpose, the stretching rod 53 is carried by a mechanism which co-operates with static elements integrally constrained to the carrying frame 3, and as a result of this co-operation, the stretching rod 53 moves relative to the pivot structure 23, 25, 27.

[0085] In the illustrated embodiment, the stretching rod 53 is carried by two pivot levers 55, each pivot rod being associated with a respective pivot arm 23, 25. The two pivot levers 55 (in Figure 8 and Figure 9Only one of them is visible in [description] is hinged about a pivot axis 57 which is integral with the pivot arms 23, 25 and is substantially parallel to the pivot axis 29. Each pivot lever 55 has a first end 55.1 constrained to the tension rod 53 and a second end 55.2 arranged near the second guide roller 35. The second end of each pivot lever 55 forms a movable support which co-operates with a corresponding support 59 mounted on the support frame 3. Each support 59 can be fixed or almost fixed, for example it can be a resilient support for cushioning the impact of the end 55.2 of the pivot lever 55. The resilient member 59.1, such as a pneumatic spring, can gradually contract when the pivot arms 23, 25 reach the maximum raised position. The contraction of the resilient member 59.1 allows the corresponding support 59 to pivot upwards under the thrust of the end 55.2 of the corresponding pivot lever 55, while the pivot point (axis 57) of the latter follows the upward movement of the pivot structure 23, 25, 27 (see Figure 9 ). The resilience provided by each of the two resilient members 59.1 allows any stretching or contraction of the continuous flexible member 31 to be compensated for, thus ensuring that it is always fully stretched by the tension rod 53.

[0086] As Figure 9 shown, when the pivot structure comprising the pivot arms 23, 25 and the crossbeam 27 (on which the tension rod 53 is rotatably supported) is lifted until it reaches the position of maximum distance from the second corrugating roller 27, the tension rod rotates about the axis 57 due to the co-operation of the end 55.2 of the pivot lever 55 and the support 59. Thus, the tension rod 53 pushes the second branch of the continuous flexible member 31 and stretches the first branch of the continuous flexible member, thereby preventing it from tending to sag downwards into the area of the roller boxes 13 of the moving corrugating rollers 15, 17. Basically, as Figure 5 and 8 clearly shown, when the pivot structure is in the raised position, the continuous flexible member 31 is stretched between the two guide rollers 32, 35 and the tension rod 53. This makes it easier to move the roller boxes 13 and there is no risk of damaging the continuous flexible member 31.

[0087] In some embodiments, the single-sided corrugating machine 1 can include means for facilitating the replacement of the continuous flexible member 31. In fact, this member is subject to wear due to high thermal and mechanical stresses.

[0088] To facilitate the replacement of the continuous flexible member 31, the pivoting structure including the pivoting arms 23, 25 and the crossbeam 27 is constrained to the bearing frame 3 so that the guide rollers 32, 35 can be supported in a cantilever manner on one of the two pivoting arms and the continuous flexible member 31 can be removed from the other side of the pivoting arm. In the example shown, as will be described in more detail below, the first pivoting arm 23 is constrained to the bearing frame 3 so that the first guide roller 32, the second guide roller 35 and the second pivoting arm 25 can be supported in a cantilever manner (which can be temporarily detached from the bearing frame 3 to allow the removal and replacement of the continuous flexible member 31 from the side of the second pivoting arm 25).

[0089] Specifically referring to the figures such as Figure 13 、 14 and 23 shown, the first pivoting arm 23 includes a crossbeam 23.3 rigidly connected to the pivoting arm 23 and extending in a cantilever manner substantially parallel to the pivoting axis 29. The pivoting arm 23 with the corresponding crossbeam 23.1 defines two hinges 23.2 and 23.3 (specifically see Figure 23 ), which are coaxial with each other and spaced apart along the direction of the pivoting axis 29. The two hinges 23.2 and 23.3 form elements for constraining the pivoting arm 23 to the bearing frame 3 on the side of the side wall 5.

[0090] The two spaced-apart hinges 23.2, 23.3 provide a constraint on the first pivoting arm 23. The arm 25 is also held in a cantilever manner by means of the crossbeam 27, which connects the pivoting arms 23, 25 to each other. Finally, the guide rollers 32, 35 and the pivoting arms 23, 25 are supported by the hinge system 23.2, 23.3, which connects the pivoting arm 23 to the bearing frame 3. In this way, the pivoting arm 25 can be detached from the bearing frame 3, thus allowing the easy replacement of the continuous flexible member 31 as described below.

[0091] In the embodiment shown, the second pivoting arm 25 is constrained and pivoted to the bearing frame 3 by means of the hinge 25.1, specifically as Figure 14 shown. The second pivoting arm 25 is provided with a removable bracket 25.2 that connects the pivoting arm 25 to the hinge 25.1, specifically see the side view of the second side of the single-face corrugating machine 1 ( Figure 2 、 4 、7、11、12). The function of the bracket 25.2 will be elucidated with reference to the operating sequence for removing the worn continuous flexible member 31. These operations are described in detail in Figure 7 、 8 and 10 to 13.

[0092] Figure 7 and 8The preliminary operations necessary to clear the space required for replacing the continuous flexible member 31 are shown for the single facer corrugator 1 from which the roll cassette 13 has been removed.

[0093] from Figure 7 , 8 The pivot structure comprising the pivot arms 23, 25 and the crossbeam 27 with the two guide rollers 32, 35 is lowered by rotating about the pivot axis 29 until it reaches a position below the normal working position, i.e. below the position where the supports 23A, 25A of the pivot arms 23, 25 rest on the supports 13A of the roller box 13 located in the single-face corrugated machine 1.

[0094] The lowered position of the pivot structure is Figure 10 is shown on the side of the side wall 5, and Figure 11 and Figure 12 6 is shown as the side away from the side wall 7. The position of the pivot structure in this operation step is defined by the fixed support 61 and the movable support 63. The fixed support 61 is integrated with the supporting frame 3, more precisely, with the first side wall 5 of the supporting frame 3. The movable support 63 is integrated with the first pivot arm 23. During the step of replacing the continuous flexible member 31, the supports 61, 63 allow to define a lower position of the pivot structure and give greater stability to the pivot arm 23.

[0095] At the lower part of the hinge structure, such as Figure 10 , 11 12 , the continuous flexible member 31 is no longer held in traction by the stretching rod 53 , and its first branch is loosely suspended in the space left by the roller box 13 with the corrugating rollers 15 , 17 .

[0096] When this position is reached, in order to remove the continuous flexible member 31, the second pivoting arm 25 is first separated from the side wall 7 of the supporting frame 3. To this end, Figure 11 and 12 As shown, the bracket 25.2 is separated from the rest of the arm 25 and rotated downward about the pivot axis 29. In addition, as shown in Figure 11 and 12 As shown, the actuator 43 is separated from the arm 25.

[0097] In some embodiments not shown, the articulated arm 25 may not be articulated to the carrier frame 3 by means of its hinge. In this case, no bracket 25.2 is provided, and the disengagement of the articulated arm 25 from the carrier frame 3 is faster, since it only requires the actuator 43 to be separated.

[0098] exist Figure 12In [the figure], the arm 25 is substantially separated from the carrying frame 3. It is held in a cantilever manner by a crossbeam 27 that is constrained to the pivot arm 23. This is constrained to the carrying frame 3 by two hinges 23.2, 23.3, an actuator 41, and a support 63 that rests on a support 61.

[0099] Thus, as Figure 13 shown in the isometric view of [the figure], the continuous flexible member 31 can be removed from the guide rollers 32, 35. Once the worn continuous flexible element 31 has been removed, it can be replaced with a new continuous flexible element 31. The guide rollers 32, 35, the continuous flexible member 31, and the pivot arms 23, 25 are returned to the Figure 6 , 7 lifting positions of [the figure] by an operation contrary to the above operation.

[0100] In this position, the new continuous flexible member 31 is held in tension by the tension rod 53, such that the first branch of the continuous flexible member 31 assumes a straight shape and clears the space below, in which the first corrugating roll 15 and the second corrugating roll 17 are inserted into the roll box body 13 ( Figure 3 , 4 and Figure 5 ). Subsequently, the extrusion unit including the continuous flexible member 31, the guide rollers 32, 35, the pivot arms 23, 25, and the crossbeam 27 is lowered to the working position ( Figure 1 and Figure 2 ).

[0101] When the single - facer corrugating machine 1 is in the working position, the continuous flexible member 31 must be held in correct tension and guided around the guide rollers 32, 35. The width of the continuous flexible member 31 and the axial length of the guide rollers 32, 35 are very large relative to the length of the continuous flexible element. This makes guiding the continuous flexible member 31 particularly critical. To keep the continuous flexible member 31 correctly tensioned and guided, the adjustment and guiding arrangement of the continuous flexible member 31 as specifically referred to Figures 14 to 23 above is provided. This system is used to maintain the correct tension of the continuous flexible member 31 to prevent or correct any slippage in the transverse direction, i.e., displacement along the axes of the guide rollers 32, 35, and to avoid or correct the twisting of the continuous flexible member 31. Twisting occurs when the two edges of the continuous flexible member 31 advance unevenly, such that the line of the continuous flexible member 31 that was originally parallel to the rotational axes of the guide rollers 32, 35 is displaced, so that its position is no longer parallel to such rotational axes.

[0102] In the illustrated embodiment, pivot arms 23, 25 are associated with respective actuators that independently adjust the distance between the rotational axes of two guide rollers 32, 35 on both sides of the single-face corrugating machine 1. Further, another actuator is provided on one of the two sides of the single-face corrugating machine 1, which is associated with one end of one of the two guide rollers 32, 35 and adjusts the inclination of the axis of this guide roller in the transverse direction, preferably substantially orthogonal to the adjustment direction of the center distance of the guide rollers.

[0103] More specifically, the first guide roller 32 is supported on the first pivot arm 23 by means of a first support 32.1 and on the second pivot arm 25 by means of a second support 32.2. Similarly, the second guide roller 35 is supported on the first pivot arm 23 by means of its first support 35.1 and on the second pivot arm 25 by means of a second support 35.2.

[0104] In the illustrated embodiment, as detailed below, the supports 35.1 and 35.2 of the second guide roller 35 are mounted in fixed positions relative to the first pivot arm 23 and the second pivot arm 25, while the supports 32.1 and 32.2 of the first guide roller 32 are mounted such that they can move relative to the first pivot arm 23 and the second pivot arm 25 in a controlled manner.

[0105] In the illustrated embodiment, the first support 32.1 of the first guide roller 32 and the second support 32.2 of the first guide roller are mounted in respective movable units, one of which is indicated in detail by reference numeral 71 in the sectional view of Figure 20 The supports 32.1 and 32.2 are pivot supports, that is, they allow the inclination of the rotational axis 33 of the first guide roller 32 to be changed in the following manner for the following purposes.

[0106] The movable unit 71 contains the first support 32.1 of the first guide roller 32 and connects it to the first pivot arm 23 as described below. For a similar movable unit 72, the second support 32.2 of the first guide roller 32 is mounted on the second pivot arm 25 in the same manner, with reference to Figure 17 、 18 、19 and 20.

[0107] Specifically referring to Figure 20 ,the movable unit 71 has a base 71.1 for the first support 32.1 of the first guide roller 32. The movable unit 71 is constrained to the pivot arm 23 by means of a rocker arm 73, one end of which is pivoted to the movable unit 71 and the other end is pivoted to the pivot arm 23. The axes for pivoting the rocker arm 73 to the arm 23 and the movable unit 71 are indicated by reference numerals 73.1 and 73.2 respectively.

[0108] The movable unit 71 is further constrained to the pivot arm 23 by means of a first actuator 75 which is adapted to adjust the traction force of the continuous flexible member 31. In the illustrated embodiment, the first actuator 75 is a linear actuator, such as a cylinder-piston actuator, preferably of the double-acting hydraulic type.

[0109] In the illustrated embodiment, the actuator 75 includes a cylinder 75.1 formed in the movable unit 71 within which a piston 75.2 slides. Further, the rod of the piston 75.2 is pivotally connected to the first pivot arm 23 at 75.3. Movement of the actuator 75 causes the pivoting of the rocker arm 73 and the follow-up movement of the axis of rotation 33 of the first guide roller 32 relative to the pivot arm 23.

[0110] A similar arrangement is provided for connecting the second support 32.2 of the first guide roller 32 to the second pivot arm 25.

[0111] Due to the variation in the distance between the axes of rotation 33 and 37 of the two guide rollers 32, 35, the two actuators 75 acting on the two supports 32.1 and 32.2 associated therewith allow the traction force of the continuous flexible member 31 to be changed.

[0112] The two actuators 75 on the two sides of the single-face corrugator 1 can be actuated independently of each other in the sense that they allow independent adjustment of the positions of the respective supports 32.1 and 32.2 of the first guide roller 32 relative to the respective supports 35.1 and 35.2 of the second guide roller 35. This allows the continuous flexible member 31 to be properly guided and properly stretched. The independent actuation of the actuators 75 allows the inclination of the axis of rotation 33 of the first guide roller 32 to be changed such that it is not exactly parallel to the axis of rotation 37 of the second guide roller 35. This change in inclination can be used, for example, to compensate for or correct for the twisting of the continuous flexible member 31.

[0113] The actuator 75 can be controlled by a control unit (not shown) based on signals from sensors (not shown) provided in the single-face corrugator 1. For example, a load cell for detecting the traction force of the continuous flexible member 31 can be provided, which traction force corresponds to the determined pressure on the second corrugating roller 17 and thus to the determined adhesive pressure between the smooth paper web and the grooved paper web. In addition, sensors for reading the position of one or both longitudinal edges of the continuous flexible member 31 can be provided. As an alternative, the traction force can simply be determined based on the pressure of the hydraulic fluid used to control the actuator 75.

[0114] More specifically, based on the signals of these sensors, it is possible to correct a possible displacement of the continuous flexible member 31 by differentially acting on the two actuators 75, thereby causing a change in the inclination of the rotation axis 33 of the first guide roller 32. Since it acts on the two actuators 75 simultaneously, it will cause the rotation axis 33 to translate parallel to itself by applying the same movement thereon, thereby changing the traction force of the continuous flexible member 31.

[0115] In the illustrated embodiment, the pivot axis 73.1 of the rocker arm 73 associated with the pivot arm 25 is fixed (see Figure 18 ). On the other hand, the pivot axis 73.1 of the rocker arm 73 associated with the pivot arm 23 is movable to apply a further adjustment movement to the first guide roller 32. This further movement will be more apparent with reference to 19, 20 and 21. The pivot axis 73.1 of the rocker arm 73 associated with the first pivot arm 23 includes an eccentric member 73.3, and the eccentric member 73.3 is received in the base 73.4 of the pivot arm 23 (see Figure 20 ). The eccentric member 73.3 rotates in the base 73.4 about an axis 73.5 that is parallel to but spaced from the pivot axis 73.1 of the rocker arm 73. In the illustrated embodiment, the rotation of the eccentric member 73.3 is controlled by a linear actuator 77 (such as an electric jack) by means of a lever 79 (see Figure 19 ).

[0116] The rotation of the eccentric member 73.3 about the axis 73.5 causes a displacement of the pivot axis 73.1 of the rocker arm 73 relative to the pivot arm 23. In Figure 20 , the general direction of this displacement is indicated by the reference numeral f73. This direction is transverse to the direction of displacement imparted by the linear actuator 75, which is indicated by the reference numeral f75. Thus, on the side of the first pivot arm 23, the first support 32.1 of the first guide roller 32 can be displaced according to two generally orthogonal directions. The displacement imparted by the actuator 75 according to the arrow f75 ( Figure 20 ) is used to adjust the traction force of the continuous flexible member 31, and it can be coordinated with the corresponding movement imparted by the corresponding actuator 75 of the second support 32.2. The displacement imparted by the actuator 77 by means of the eccentric member 73.3 can be used to correct the displacement of the continuous flexible member 31 parallel to the rotation axes of the guide rollers 32, 35, such as a lateral slip. A homologous displacement of the support 32.2 on the side of the second pivot arm 25 is not necessary.

[0117] Figures 24A to 28B Further details are shown that facilitate understanding of the control of the traction force and the position of the continuous flexible member 31. More particularly, Figure 24A and 24BThe details of the pivot arms 23, 25 and the continuous flexible member 31 guided around the guide rollers 32 and 35 are shown in an axonometric view. Figure 24A and 24B A sensor for detecting the displacement of the continuous flexible member 31 is shown, which provides a signal to the central control unit 101 that controls the above actuator to keep the continuous flexible member 31 in the correct position.

[0118] In the illustrated embodiment, at least one respective sensor 103, such as a magnetic sensor, is arranged on each pivot arm 23, 25, which detects the twist of the continuous flexible member 31. For this purpose, elements that can be detected by the sensor 103, such as two magnets 105, are inserted along the two edges of the continuous flexible member 31. The two magnets 105 are arranged on a line orthogonal to the edge of the continuous flexible member 31. Thus, if the continuous flexible member 31 does not show any twist or bend, they pass through the front of the respective sensors 103 simultaneously. The twist of the continuous flexible member 31 causes the two magnets 105 to shift relative to each other along the advancing direction of the continuous flexible member 31. This is detected by the delay of the signal of one sensor 103 relative to the signal of the other sensor, and this provides the central control unit 101 with information on the need to correct the two actuators 75 by means of differential actuation.

[0119] The possible lateral sliding of the continuous flexible member 31 can be detected by a corresponding arrangement of sensors. In the illustrated embodiment, a sensor 107 is provided on one of the pivot arms 23, 25 and more specifically on the pivot arm 23 in the illustrated example. The sensor 107 can be an optical sensor, for example including one or more optoelectronic elements arranged orthogonally to the edge of the continuous flexible member 31 to identify its position. For example, a fiber optic sensor can be used, which has multiple optical fibers along a direction orthogonal to the edge of the continuous flexible member, and which detects the optical signal from a relative emitter located on the opposite side of the continuous flexible member 31. The lateral sliding of the continuous flexible member 31 in one direction or the other causes a change in the number of optoelectronic elements or optical fibers that see the optical signal emitted by the relative emitter. The central control unit 101 uses the obtained signal to emit a control signal for the linear actuator 77 to correct any sliding.

[0120] The possibility of using a combined movement of the actuators 77 and 75 to correct sliding and twist movements cannot be excluded.

[0121] Figure 25A and 25B More details are shown on how the control of the traction force of the continuous flexible member is carried out by the simultaneous actuation of the actuator 75.

[0122] In Figure 25A the continuous flexible member 31 is not stretched, while in Figure 25BIn it, due to the influence of the equal elongation of the two actuators 75 and the following movement of the guide roller 32 away from the guide roller 35, it is stretched, thereby keeping the axes of the two guide rollers parallel to each other.

[0123] Figure 26 and 27 shows the displacement of the first guide roller 32 caused by the linear actuator 77 for correcting the lateral sliding movement of the continuous flexible member. More specifically, Figure 26 is the rear view of XXVI-XXVI according to Figure 27 , while Figure 27 is the Figure 26 side view of XXVII-XXVII of the extrusion unit 21. The two inclined positions of the first guide roller 32 are indicated by reference numerals 32X and 32Y. For the sake of clarity, this displacement is shown to be much larger than the actual displacement.

[0124] Figure 28A and 28B show the displacement of the first guide roller 32 controlled by the differential stroke of the actuator 75 in a top view of the extrusion unit 21 for correcting the possible twisting of the continuous flexible member 31. The positions of the first guide roller 32 inclined in opposite directions obtained by means of the differential action of the actuator 75 are indicated by reference numerals 32Z and 32W. Just as in Figure 26 and 27 , in Figure 28A , 28B this displacement is also shown to be much larger than the actual displacement for clearer representation.

[0125] The present invention has been described according to various specific embodiments. However, it is obvious that many modifications, changes and omissions can be made by those skilled in the art without departing from the spirit and scope of the present invention defined by the appended claims.

Claims

1. A single - facer corrugating machine (1) for manufacturing single - facer corrugated cardboard, comprising: A carrier frame (3); A first corrugating roll (15) and a second corrugating roll (17), the first corrugating roll and the second corrugating roll meshing with each other and being associated with the carrier frame (3); A pivoting structure that is pivotally connected to the carrier frame (3) about a pivot axis (29) and includes a first pivoting arm (23) on a first side of the single - facer corrugating machine (1) and a second pivoting arm (25) on a second side of the single - facer corrugating machine (1); A first guide roll (32) having a first rotation axis (33), which is supported by a corresponding first support (32.1) on the first pivoting arm (23) and by a corresponding second support (32.2) on the second pivoting arm (25); wherein the first support (32.1) of the first guide roll (32) is movably mounted on the first pivoting arm (23), and the second support (32.2) of the first guide roll (32) is movably mounted on the second pivoting arm (25); A second guide roll (35) having a second rotation axis (37), which is supported by a corresponding first support (35.1) on the first pivoting arm (23) and a corresponding second support (35.2) on the second pivoting arm (25); wherein the first support (35.1) of the second guide roll (35) is fixedly mounted on the first pivoting arm (23), and the second support (35.2) of the second guide roll (35) is fixedly mounted on the second pivoting arm (25); A continuous flexible member (31) that is guided around the first guide roll (32) and the second guide roll (35); A control system (41, 43) that can rotate the pivoting structure around the pivot axis (29) to position it in a working position and a raised position, in the working position the continuous flexible member (31) is pressed against the second corrugating roll (17), and in the raised position the first guide roll (32) and the second guide roll (35) are spaced apart from the second corrugating roll (17); A device for adjusting and guiding the continuous flexible member, comprising: - A first actuator (75), which is associated with the first pivoting arm (23) and can adjust the distance between the first support (32.1) of the first guide roll (32) and the first support (35.1) of the second guide roll (35) by controlling the movement of the first support (32.1) of the first guide roll (32) on the first pivoting arm (23); - A second actuator (75), which is associated with the second pivoting arm (25) and The distance between the second support member (32.2) of the first guide roller (32) and the second support member (35.2) of the second guide roller (35) can be adjusted by controlling the movement of the second support member (32.2) of the first guide roller (32) on the second pivot arm (25); the first actuator (75) and the second actuator (75) can be actuated independently of each other; - a third actuator (77) on one of the first pivot arm (23) and the second pivot arm (25), the third actuator being able to adjust the position of the corresponding support member (32.1) of the first guide roller (32) in the lateral direction relative to the adjustment direction of the corresponding first actuator (75) or second actuator (75).

2. The single-sided corrugating machine (1) according to claim 1, wherein, The first actuator (75) and the second actuator (75) are linear actuators.

3. The single-sided corrugating machine (1) according to claim 1, wherein, The second guide roller (35) is motor-driven.

4. The single-sided corrugating machine (1) according to claim 2, wherein, The second guide roller (35) is motor-driven.

5. The single-sided corrugating machine (1) according to claim 3, wherein, The distance between the rotational axis (33) of the first guide roller (32) and the pivot axis (29) of the pivot structure is arranged to be less than the distance between the rotational axis (37) of the second guide roller (35) and the pivot axis (29) of the pivot structure.

6. The single-sided corrugating machine (1) according to claim 4, wherein, The distance between the rotational axis (33) of the first guide roller (32) and the pivot axis (29) of the pivot structure is arranged to be less than the distance between the rotational axis (37) of the second guide roller (35) and the pivot axis (29) of the pivot structure.

7. The single-sided corrugating machine (1) according to any one of claims 1 to 6, wherein, The third actuator (77) acts on an eccentric member (73.3), the rotation of which causes the corresponding support member (32.1) of the corresponding guide roller (32) to be displaced in a direction having at least one component transverse to the movement direction of the corresponding first actuator (75) or second actuator (75).

8. The single-sided corrugating machine (1) according to any one of claims 1 to 6, wherein, The first support member (32.1) and the second support member (32.2) of the first guide roller (32) are respectively mounted in a first movable unit (71) constrained to the first pivot arm (23) and a second movable unit (72) constrained to the second pivot arm (25); wherein, the first movable unit (71) is constrained to the first pivot arm (23) by means of the first actuator (75) and by means of a first rocker arm (73), the first rocker arm being pivotally connected to the first pivot arm (23) about a first pivot axis which is substantially parallel to the pivot axis (29) of the pivot structure; wherein, the second movable unit (72) is constrained to the second pivot arm (25) by means of the second actuator (75) and by means of a second rocker arm (73), the second rocker arm being pivotally connected to the second pivot arm (25) about a second pivot axis, the second pivot axis being substantially parallel to the pivot axis (29) of the pivot structure; and wherein, the pivot axis of at least one of the first rocker arm (73) and the second rocker arm (73) can be adjusted by means of the third actuator (77).

9. The single-sided corrugating machine (1) according to claim 8, wherein, The adjustable pivot axis is defined by an eccentric (73.3), the rotation of which is controlled by the third actuator (77).

10. The single-sided corrugating machine (1) according to claim 8, wherein, The first actuator (75) is a linear actuator having a first end hinged to the first pivot arm (23) about an axis substantially parallel to the pivot axis (29) of the pivot structure and a second end rigidly connected to the first movable unit (71); and wherein the second actuator (75) is a linear actuator having a first end hinged to the second pivot arm (25) about an axis substantially parallel to the pivot axis (29) of the pivot structure and a second end rigidly connected to the second movable unit (72).

11. The single-sided corrugating machine (1) according to any one of claims 1 to 6, wherein, The first corrugating roll (15) and the second corrugating roll (17) are mounted on an interchangeable cartridge (13) that can be removed from one side of the single facer (1).

12. The single-sided corrugating machine (1) according to any one of claims 1 to 6, comprising: A central control unit (101); at least a first sensor device (107) for detecting the position of at least one longitudinal edge of the continuous flexible member (31); at least a second sensor device (103) for detecting the offset between the two longitudinal edges of the continuous flexible member (31); and wherein the central control unit (101) is functionally connected to the means for adjusting and guiding the continuous flexible member (31) to hold the continuous flexible member (31) in the correct position by acting on the continuous flexible member (31) by means of the first actuator (75), the second actuator (75) and the third actuator (77).

13. The single-sided corrugating machine (1) according to claim 1, wherein, The first actuator (75) and the second actuator (75) are cylinder-piston actuators.

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