TECHNICAL FIELD

[0001] The present invention relates to an unwinder for unwinding reels of web products, such as paper, with a system for exchanging the web between a new reel and an almost complete ly unwound reel made to be simple and optimise spaces.

BACKGROUND ART

[0002] In the conversion industry, a web product, wound in reels, must be unwound to be sent to the downstream machines for further processing.

[0003] The unwinding machine has the purpose of controlling the rotation of the reel in the unwinding step and, in order to make the process more efficient, has systems for speeding up the evacuation of the unwound reel and the loading of the new reel; the unwinder lastly has devices for connecting the first web of the unwound reel to the second web of the new reel.

[0004] In the paper conversion industry, for example, where there is a need to create prod ucts with multiple paper webs, two to four unwinders with reel diameters generally greater than two metres in diameter can be used, it is understandable that the space they occupy may be a problem or disadvantage.

[0005] Patent GB1312185A discloses a method in which an unwinding reel and a new reel are loaded at the ends of a rotary support which is made with a pair of parallel arms, connected in the centre by a tubular, around which two motorised belt systems are made to transmit independ ent rotation to each reel. The tubular itself is the fulcrum on which the rotary support rotates to re verse the position of the reels and in particular, in the exchange step between the webs, the rotary support brings the new reel in contact on a device adapted to cut the web of the unwound reel and join the webs by means of a glue product.

[0006] Disadvantageously, the latter device is not economical but, above all, the unwinder assembly requires a space in length greater than twice the diameter of the reel itself, therefore dif ficult to use when the reels to be unwound are very large, around two or three metres in diameter. Patent ITFI20110253 - WO2013076011A1 allows the exchange between the unwound reel and new reel without stopping the machines. It describes an unwinder where the unwinding reel is at a certain position P2 and the second new reel is placed waiting in another overlying position P1, so as not to occupy horizontal space.

[0007] In a third position P3, the unwound reel is then transferred to allow the evacuation step.

[0008] This method has the disadvantage of requiring a loading of the new reel at a consid erable height, in fact, in addition to requiring a space at a height at least twice the diameter of the reel, the unwinder poses difficulties from a safety point of view considering the placement of signif icant weights of reels on supports placed at heights, not easy to control in the loading step.

[0009] The unwinder is furthermore not economical for the various reel transfer devices from the positions P1 , P2 and P3. Patent W02004/080867A2 describes an unwinder where the loading of the reel is from the bottom by means of a carriage, which has elements to transmit the rotation movement to the reel itself in order to prepare the paper flap in the exchange position, and a first support picks it up, by punching on the cardboard core, bringing it to the unwinding area by means of motorised belts.

[0010] In the final unwinding step the reel is transferred from the first support to an overlying position to allow the side entry of a new reel by means of the carriage and the punching and pick ing step is repeated by means of a second support.

[0011] Once rotated, the paper is exchanged between the web of the overlying almost com pletely unwound reel by means of a device which connects the paper by mechanical pressure be tween knurled wheels, and the use of double-sided adhesive tape is not envisaged.

[0012] This method allows to obtain an unwinder with rather small dimensions and there is a joining system between the first and the second web of the new reels, without interrupting the un winding process, but it is a very complex machine.

[0013] In fact, there are two supports to move the unwound reel and the new reel which must alternate in position, with mechanisms requiring many mechanical and electronic parts to manage their synchronisation, all making the unwinder complicated and expensive.

SUMMARY OF THE INVENTION

[0014] The object of the present invention is to provide an unwinder for unwinding reels of web products, in particular of large diameter reels, such as paper reels for feeding conversion lines, which overcomes in whole or in part the drawbacks of the known devices. In particular, the object is to propose an unwinder with a new reel loading point which is not particularly high, im proving safety in this work step.

[0015] Another object is to realise an unwinder with a very small footprint, which is particular ly important when a multiplicity of unwinders, for example up to four, are required in the same con version line.

[0016] Another object is to have an automatic and simple exchange system between the pa per of the unwound reel and the paper of the new reel, so as not to stop the unwinding process.

[0017] Another object is to allow the exchange between the paper indifferently using meth ods by mechanical pressure, use of glue or by double adhesive tape, as the application of each is bound to the product type of the reel. Lastly, another object is to propose an unwinder with a sim ple operating logic and which is economically advantageous.

[0018] The objects set forth above and still others are achieved by means of an unwinder comprising:

- A fixed support structure.

- A rotary support structure rotating with respect to a barycentric horizontal axis, intended to support two reels at two opposite ends with respect to said barycentric horizontal axis, said reels also being arranged with a horizontal axis; a barycentric support member for the sup port and rotation of said rotary support structure (composed of at least one rotating sleeve inside the fixed support structure); drive members being adapted to control the rotation of said rotary support structure (composed of at least one arm, connected, at its centre point, to the structure through a barycentric support member) - A system for transmitting the rota tional motion to the rotating sleeve).

- First unwinding control devices adapted to rotate one of said reels around its own axis dur ing unwinding (preferably consisting of continuous flexible elements, such as motorised belts, which operate on the periphery of the reel itself).

- Second unwinding control devices adapted to control one of said almost completely un wound reels in rotation around its axis (preferably consisting of a roller with a braking sys tem of its rotation which operates on the periphery of the reel itself). - A paper cutting system for separating the unwinding paper web, separating the paper web unwound from the relative reel (preferably consisting of a toothed blade).

- A joining system for joining paper from two superimposed paper webs, of which one paper web is unwound from an almost completely unwound reel and one paper web is unwound from a new reel to be unwound (obtained by the pressure exerted between knurled wheels or a joining system, obtained by pressing a roller on a double-sided tape previously pre pared on the new reel).

[0019] An unwinder as outlined above is characterised in that it has a rotary support struc ture for simultaneously moving two reels, the radius of rotation of which is less than the radius of the new reel, so as to greatly reduce the dimensions and the resistant torque necessary for the ro tation control.

[0020] Advantageously, the loading point of the new reel is at a very low or relatively low height.

[0021] Advantageously, the first new reel is loaded onto the rotary support structure, which brings it into contact with the motorised belts.

[0022] Advantageously, the continuous rotation of the rotary support structure, in the direc tion towards the motorised belts, compensates for the reduction in the diameter of the reel due to the unwinding of the paper.

[0023] Advantageously on the rotary support structure, at the end opposite where the un winding reel is present which in turn has reduced the diameter, it is possible to load a new reel.

[0024] Advantageously, the newly loaded reel is carried by the rotary support structure in contact with the motorised belts, while the first reel unwinding and in the almost completely un wound step is moved away from the motorised belts.

[0025] Advantageously, without the need to stop the unwinding, the paper of the new reel, placed in rotation by the motorised belts, will advance in the same direction as the paper of the al most completely unwound reel and cross the pressure members for the connection step between the two paper webs.

[0026] Advantageously, the rotary support structure brings the paper of the unwound reel closer to a toothed blade, which makes the separation cut. [0027] Advantageously, the loading of the new reel can be carried out from above by means of a bridge crane system or from the side with the insertion through a carriage, all while maintaining the exchange of the paper between the new reel and the almost completely unwound reel without stopping the process, but only with a reduction of the speed in a short step.

[0028] Advantageously, the unwinder can also be made without the motorised belts for moving the reel, but with the rotary support structure, having the ends equipped with motorised or braking punches, according to the type of product to unwind, for example in the case of cardboard, braking punches are sufficient.

[0029] Advantageously, the unwinder may use reels with a rod provided with bearings or reels with two engaged punches provided with bearings, or have free reels as the unwinder itself may be provided with punches directly engaging the reel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other advantages and embodiments of the present invention will be better understood from the following description and with the aid of the accompanying drawings, provided by way of example, but not to be considered as limiting, which show:

Figs. 1 to 6 the side view of the unwinder in an operating sequence according to the present invention where the reels are provided with rod with bearings.

Fig. 7 a front view of the unwinder shown in Fig. 1.

Fig. 8 is an embodiment of the unwinder of the present invention with a side loading of the new reel with translation means such as carriages.

Fig. 9 a front view of an embodiment of the unwinder of the present invention in the case where a very narrow reel is unwound.

Fig. 10 a side view of the embodiment of Fig.9.

DESCRIPTION OF AN EMBODIMENT

[0031] With reference to Figs.1 and 7, the main elements of an unwinder according to the present invention will first be described in a possible embodiment.

[0032] The unwinder, as a whole indicated by 1, is almost completely specular according to the plane passing through the axis y and is therefore composed of a pair of fixed support structures 2, on the internal side of each of which are mounted rotary support structures 5 which have, at their ends at an equidistant position from a barycentric axis X1 , reel supports 7 with axis X2, adapted to support the reels.

[0033] The two rotary support structures 5 are installed so as to be free to rotate with respect to a same barycentric horizontal axis X1.

[0034] The rotary support structures 5 have an elongated shape of which an external side 52 and an internal side 51 can be identified and respectively on their external side 52 they are connected to the fixed support structures 2 by means of barycentric support members, for support and rotation, and on the internal side 51 they have the two reel supports 7.

[0035] The barycentric support members, which are made by means of rotating sleeves 3, free to rotate in the fixed support structures 2 by means of bearings 4, then have connected driven pulleys 6 which, through belts 10, receive motion from the drive pulleys 11, in turn rigidly installed on a torsion bar 17, located in an area which does not cross the overall footprint of the reels.

[0036] The torsion bar 17, receiving the motorisation from a motor 12, thus allows the synchronisation of the rotational motion to the two rotary support structures 5.

[0037] Another embodiment for the transmission of the rotation torque to the two rotary support structures 5, is to use two independent motors which, through a reduction ratio and therefore through mechanical reducers, operate for each side external to the fixed support structure 2 for the rotation of the rotary support structures 5.

[0038] The above-described examples of mechanical transmission of the rotational motion allow to completely free the internal space 51 between the two rotary support structures 5 at their barycentric horizontal rotation axis X1 whereby, advantageously, a new reel Bn with a radius greater than the distance between the axis X2 of the relative reel support 7 and the barycentric axis X1 of the rotary support 5 can be loaded. Furthermore, this type of mechanical and geometric execution, by virtue of the high value of the ratio between the diameter of the new reel Bn and its radius of rotation on the barycentric horizontal axis X1, advantageously allows to limit the value of the rotational torque to be applied to the rotary support structures 5, considering the fact that the weights of the reels can reach up to 5 tons.

[0039] When using reels coming directly from paper production plants, the reels themselves are already arranged with a rotatable rod A, on which the winding has been generated, whereby the new reel Bn can be advantageously taken directly from the reel supports 7 on board the rotary support structures 5. In this example, the reel supports 7 are adapted to accommodate the end diameters of the rod A inserted in the new reel and to constrain the same shaft A in the reel supports 7 by means of a system made with locking levers 8 controlled by pneumatic cylinders 9.

[0040] Advantageously, therefore, the reel supports 7, by virtue of the movement of the rotary support structures 5 around the barycentric horizontal rotation axis X1 , can pick up a new reel Bn from a fixed parking point and then release it, after it has been unwound, in a second storage station, operating respectively also with the closing and opening of the locking levers 8.

[0041] If the reels have not inserted on the axis any rod A or any cylindrical part, in jargon called punch, inserted on each side in the cardboard core of the reel itself, the rotary support structure 5 can be provided, alternatively, with conical tips on the reel supports 7, later described below, with the ability to move orthogonally in order to be able to insert and disengage in the cardboard core of the reels themselves.

[0042] Ultimately, by virtue of the following invention, the rotary support structures 5 may both advantageously be able to pick up new reels Bn and release unwound reels Be towards storage areas, by means of different constraint systems, and have the benefit of the geometric relationship between rotation radius and diameter of the new reel with the advantages described above.

[0043] The first unwinding control devices, for transmitting the rotational motion to the new reel Bn, is in this example of Fig. 7, realised through a pair of motorised belts 13 closed in a ring around return elements 14 such as idle pulleys, and a drive pulley 15. The latter receives motion from a motorised unit 16 composed of the motor, pulleys and drive belt.

[0044] The two motorised belts 13 have a synchronism obtained through a torsion axis 18, which transmits motion also to a second drive pulley 15 which in turn drives the second motorised belt 13.

[0045] The constant bundling maintenance of the motorised belts 13 on the unwinding reel Bs, is obtained by means of the rotational displacement of the rotary support structures (5) towards the same motorised belts 13 and the measurement of said displacement can be determined by the constant measurement of the diameter of the unwinding reel Bs. [0046] The voltage differences for any eccentricities of the unwinding reel Bs can be damped through the movement of the idle pulleys 14, mounted on fulcrum arms 20, connected with pneumatic pistons 21.

[0047] The rotary support structures 5 can finally: allow the loading of new reels Bn with a radius greater than their own rotation radius, keep the unwinding reel Bs in contact with the motorised belts 13, unload the unwound reels Be in a storage area and in particular, thanks to the geometry of the unwinder 1 of the present invention, in the exchange step, create the condition in which the paper f1 of the unwinding reel Bs can move in the direction of the paper f2 of the unwound reel Be.

[0048] Advantageously, the two papers f1 and f2 can then bundle the same diverter roller 22 which receives the motion from the motor 23. The diverter roller 22 has the purpose of being a joining means where the paper f2, of the unwound reel Be, exerts a pressure for bundling.

[0049] This pressure, by the arrangement of a glue Cb on the paper f1 of the new reel Bn, as in the example of Fig. 10, generates the joining between the two papers f1 and f2.

[0050] When a different type of joining is instead required, through the pressing of the paper only, the diverter roller 22 performs the function of contrasting the pressure members.

[0051] In this example, the pressure members used are realised with knurled wheels 24, pushed by a lever 25 by pneumatic pistons 26. To separate the paper web f2 of the unwound reel Be, near the diverter roller 22, a cutting bar 27 is provided, consisting of a tubular and a toothed blade.

[0052] The cutting bar 27 is advantageously, from a safety point of view, of a static type as it is the paper f2 itself which moves against it by virtue of the rotation of the rotary support structures 5. If necessary for more resistant web products, the cutting system can also be dynamic, i.e. , it can perform a stronger action towards the web product.

[0053] The fixed support structures 2 are made to have an upper end rib 28 for supporting the new reel Bn in a position almost corresponding to the circumferential path of the reel supports 7 rotating around the barycentric horizontal axis X1 , thus allowing a geometric condition adapted to picking up the new reel Bn itself. A lower end rib 29 instead accommodates the unwound reel Be, in the last step of the unwinding process. [0054] The lower end rib 29, being in a position almost tangent to the rod A, offers a support and guide function for rolling, until it accompanies the exit of the unwound reel Be in a storage area easily accessible by removal members thereof.

[0055] In the final step of unwinding the unwound reel Be, as a second unwinding control member, in order to better control the tension of the paper f2, a braking system acting directly on the diameter of the rod A could be installed on the rotary support structures 5.

[0056] In the example of Fig.1 , the second unwinding control member of the unwound reel Be, is realised by a control roller 30, mounted on a pair of levers 31, controlled by a pair of pneumatic cylinders 32. The control roller 30 operates the control of the unwinding by means of a commercial braking device, not shown in the drawings because known in the art.

[0057] Also, in another embodiment, the second unwinding control system of the unwound reel Be, could be motorised and for example also be made with belts to obtain, in case of unwinding very delicate products, a control of the tension from the paper f2 in a more precise manner.

[0058] Proceeding to describe the work steps, Fig. 1 shows the unwinder 1 of the present invention with the new reel Bn with its rotatable rod A, in which the type of rod used is advantageously the one where the paper is wound in the formation of reels in paper mills.

[0059] The new reel Bn, by means of the rod A, has been supported with the use of bridge cranes on the upper end ribs 28 and, advantageously, the support point is in a relatively low position or in any case we can establish that its distance from the ground does not exceed the radius of the reel itself. Thereby, the loading risks related to the potential fall height are reduced and safety is improved by obtaining greater visibility for the operator when depositing the new reel Bn itself.

[0060] This configuration of the unwinder is even more advantageous considering that its overall length is slightly greater than the diameter of the new reel Bn itself or in any case we can establish that it is less than three times its radius.

[0061] The unwinder in Fig. 1 shows the rotary support structures 5 which support, against the motorised belts 13, the unwinding reel Bs, in particular the rod A of the unwinding reel Bs is stably engaged between the reel supports 7 by closing the locking levers 8, pushed by the pneumatic cylinders 9. On the opposite side of the rotary supports 5, the locking levers 8 are in the open position allowing the rod A of the new reel Bn to freely enter the reel supports 7.

[0062] Fig. 2 shows the rotation step of the rotary support structures 5 which have picked up the new reel Bn by housing the rod A in the reel supports 7, after which the locking levers 8, through the action of the pneumatic cylinders 9, have been closed to complete the locking. On the opposite side, the unwound reel Be is brought out of contact with the motorised belts 13, but in this step the second unwinding control member of the unwound reel Be by means of the control roller 30, inserted in support on the unwound reel Be itself, by means of the levers 31 , driven by the cylinders 32, comes into operation. The unwinding is controlled by a slight braking effect and thus maintaining a tension on the unwinding paper f2. Further devices for checking the paper tension, such as load cell rollers or mobile pendular rollers, not represented here because known in the art, may advantageously be installed downstream of the unwinder.

[0063] Fig. 3 shows the rotary support structures 5, continuing their rotation, bring the new reel Bn into contact with the transmission belts 13, which in the meantime reduced their movement speed, while on the opposite side of the rotary support 5, the almost completely unwound reel Be reaches a position in which the unwinding paper f2 is almost near the cutting bar 27. The paper f1 of the new reel Bn, starting to unwind due to the action of the transmission belts 13 and their accompaniment in the direction of gravity, approaches the diverter roller 22 and the paper f2 of the unwound reel Be.

[0064] Fig.4 shows the next step where the knurled wheels 24 are pressed towards the diverter roller 22 with the thrust of the pneumatic cylinders 26. At the same time, the paper f1 of the new reel Bn which, unwinding, is placed between the diverter roller 22 and the paper f2 itself of the unwound reel Be and goes on the latter to connect by the mechanical pressure of the tips of the knurled wheels 24. The connection process, a known art, can be maintained for a determinable measure until, by continuing the rotation of the rotary support structures 5, the unwinding paper f2 of the reel Be goes to meet the cutting bar 27, separating.

[0065] Fig. 5 shows the rotary support structures 5, which have positioned the new reel Bn towards the transmission belts 13 to increase the bundling arc and, in the meantime, the unwinder 1 has returned to the maximum unwinding speed. On the opposite side, once the rod A of the unwound reel Be has reached the point of tangency with the lower end ribs 29, the locking levers 28 release the rod A itself and allow the unwound reel Be to roll by gravity to its support stroke end.

[0066] Finally, Fig. 6 shows that at the reduction of the unwinding reel Bs the bundling on the motorised belts 13 is maintained, while the unwound reel Be was removed. It is also schematically shown how the diameter of the new reel Bn is almost equal to the physical width of the unwinder 1 , which is particularly appreciated when even four unwinders are needed in sequence for the production of multiple web products f. The advantages are manifold in that, in addition to gaining physical space, the materials for the peripheral protections are reduced, the paper path is reduced, favouring the times of a slow start-up, with less dust production, etc.

[0067] The unwinder 1 of the present invention has been described with the operation with the type of joining of the paper webs by mechanical pressure, but advantageously it can also similarly operate by inserting glue by spraying, or by preparing, on the internal side of the paper f1 of the end of the new reel Bn, a double-sided adhesive tape so that it goes to glue to the paper f2 of the unwound reel Be. This type of operation will be better described in the following embodiment of Fig. 9 and 10.

[0068] Fig. 8 shows a particularly advantageous embodiment of the unwinder of the present invention 1 to be used where the heights of the ceilings of the factories do not allow the aerial loading of the reels on the unwinder. The figure shows a translation means for reels obtained with a first carriage 3T, provided with a number of four wheels 32’ for movement in a direction orthogonal to the production line of the unwinder, in this example the wheels 32’ slide inside a recess of the floor to make the upper plane of the first carriage 3T extend with the floor itself. In this example, the carriage is operated by an electromechanical actuator 35’. Above the first carriage 3T is positioned a second carriage 33’ provided with a number of four wheels 34’ for movement in the unwinding direction of the web product f by means of another electromechanical actuator 36’.

[0069] These reel translation means thus allow to manage the reels practically from ground level, where advantageously the second carriage 33’, with a concave shape to keep a new reel Bn stable, can be transferred above the first carriage 3T when it is in the position outside the production line and then transferred within the same line and in axis with the unwinder T. [0070] Subsequently, the second carriage 33’ can be advanced in the direction of the unwinder T to such an extent that, the rod A of the new reel Bn, is on the passage line of the axes X2 of the reel supports 7’ of the rotary support structures 5’.

[0071] The next loading step of the reel Bn’ is similar to that shown in the example of Fig. 2 where the rod A’ is picked up and transferred for the subsequent processing steps. Advantageously, when the unwinder T has unwound the reel Be, the same second carriage 33’ can pick it up since, analogous to the step of the example of Fig. 5, the release of the locking levers 8’ is envisaged, the transfer by gravity of the rod A from the seats 7’ on the lower end ribs 29’ and finally, in this case, the rolling of the unwound reel Be’ on the second carriage 33’ itself.

[0072] Through these translation means for reels it is advantageously possible to be able to supply a new reel Bn and to safely and automatically remove the unwound reel Be, without entering the process area of the line itself, without stopping production and making the whole process automatic and safe.

[0073] The unwinder T shown in Fig. 8, is however advantageous also in the horizontal dimension, in fact in its length dimension it is less than twice the diameter of the new usable reel.

[0074] Figs. 9 and 10 show, lastly, another embodiment according to the present invention, usable when the reels to be unwound are very narrow.

[0075] The unwinder 1” is almost analogous to a side of the unwinder 1 previously described and therefore composed of a fixed support structure 2”, in which is mounted a rotary support structure 5” free to rotate with respect to a barycentric horizontal axis X1.

[0076] From the rotary support structure 5" there is defined an internal side 51” and an external side 52”, on whose internal side 51” are positioned equidistant from the barycentric horizontal axis X1 the reel supports 37” having said axes X2, and on the external side 52” there is connected the barycentric support member for support and rotation, realised with the rotating sleeve 3” by means of two bearings 4” inserted in the fixed support structure 2”.

[0077] On the rotating sleeve 3” there is connected a motion transmission system, consisting of a driven pulley 6”, the belt 10” and the drive pulley 11” moved by the motor 12”, but a motion transmission system could also be installed by means of a gear reducer. [0078] The reel supports 37” are in this case punches adapted to move orthogonally to the structure on the rotary support 5” and consist of a pneumatic actuator 38” and a tip 39”. The latter is free to rotate on bearings and, in some cases, a system which generates resistance to rotation could be applied so that the reel supports 37” become actual unwinding control devices due to the braking tension.

[0079] The type of brake is not described here because it is known in the art and not binding on the present invention. The tip 39” may have a connection system with the cardboard core of the new reel Bn” obtained through a slight taper, which allows the tip 39” to enter and exert an expansion pressure on the cardboard core itself.

[0080] The reel supports 37” therefore advantageously have, in the loading step, the possibility of directly engaging the new reel Bn”, when it is vertical, i.e. , with its unwinding axis horizontal and resting, for example, on the ground or on any equipment T”.

[0081] In practice, the narrow reels are related to products resistant to traction, such as cardboard, and the unwinding process is carried out through the traction of the product with the downstream machines, whereby the unwinder 1” of this embodiment does not need unwinding control devices such as the transmission belts 13 as in the examples described above but can only have a motorised roller 40”, moved by the motor 44”, mounted on the lever 41” and resting on the new reel Bn, through the cylinder 42”. Its function of rotating and therefore unwinding the new reel Bn will be necessary when, as in Fig.3 of the previous examples, the exchange step must be started.

[0082] The new reel Bn, which was in this case prepared by the operator with a portion of double-sided adhesive tape Cb, applied on the internal side of its end of the cardboard f 1 , as shown in Fig. 10, will connect to the cardboard f2 of the unwound reel Be due to the adhesive effect. The joining system of the two cardboards f1 and f2, as described above, is obtained by means of the bundling pressure of the cardboard f2 of the unwound reel Be on the diverter roller 22” since, the carton f1 provided with double-sided adhesive Cb, will be interposed between the two. If necessary, other rollers could be added as a joining system to press the cardboard webs f1 and f2 on the double-sided adhesive Cb itself, so that a greater adhesion is obtained, but the operating principle just described here is sufficient to allow, with simplicity and without stopping the process, the exchange between two cardboard web products f1 and f2 of an unwound reel and a new reel.

[0083] The cardboard separation system of the unwound reel Be occurs in the same manner as described in Fig. 4 of the previous embodiment where the cutting bar 27” is fixed and the cardboard f2, due to the rotation of the rotary support structure 5", goes to intercept the cutting bar 27” itself; this step is thereby very advantageous from a safety point of view for the operators, as, moving cutting parts are avoided.

[0084] Finally, the aforementioned advantages remain safeguarded even in the presence of variants or modifications of a practical application nature which can be made by a person skilled in the art to an unwinder as described above, while remaining within the scope of protection defined by the following claims.