METHOD AND APPARATUS FOR THE PRODUCTION OF CORELESS PAPER ROLLS

Abstract

A method and apparatus for the production of coreless paper rolls, including a winding phase on a central spindle of a paper web carried out by a main reel, until the formation of a wound paper roll, a phase of extraction from the wound roll of the spindle by application of a relative axial extraction force between the roll and the spindle, where the winding phase includes a first winding phase of a number of web revolutions on the central spindle performed at a first winding tension that is lower than the next winding tension.

Claims

1. A method for producing coreless paper rolls, comprising: a step of winding a paper web onto a central spindle carried out by a main coil, until a wound paper roll is formed, and a step of extracting the central spindle from the wound paper roll by applying a relative axial extraction force between the wound paper roll and the central spindle, wherein the winding step comprises a step of first winding the paper web on the central spindle carried out at a first winding tension lower than a subsequent winding tension in order to reduce a friction between the paper web and an external surface of the central spindle and a corresponding axial force necessary to extract the central spindle from an inside of the wound paper roll in the extraction step.

2. The method according to claim 1, wherein the first winding step comprises a pneumatic winding of the paper web on the central spindle.

3. The method according to claim 1, wherein the first winding step comprises a step of rotating the central spindle according to an advancement of the paper web to be wound.

4. The method according to claim 1, wherein the winding step comprises a preliminary step of applying glue to the central spindle.

5. The method according to claim 1, comprising a transfer step of an extracted spindle at the winding step to a new winding step, wherein the extraction, transfer and winding steps are performed in a cyclical manner.

6. The method according to claim 1, wherein the extraction step takes place by retaining the central spindle in position and acting axially on the paper winding.

7. The method according to claim 6, wherein the central spindle is a hollow spindle and the retaining step is actuated by a retaining member acting by spherical radial protrusions impinging on an inner surface of an axial end portion of the central spindle.

8. The method according to claim 1, wherein the transfer step comprises a step of accumulation of a number of extracted rolls.

9. An apparatus for a production of coreless paper rolls, comprising a rewinding machine for winding a web wound by a main coil around a spindle, and an extraction device configured to receive a wound roll from the rewinding machine to extract the spindle, wherein the rewinding machine comprises: pneumatic means for the first winding of the web on the spindle in transit through a winding channel movement means of the spindle comprising a distribution of belts movable in a direction according to a direction of advancement of the web and extended in contact with the spindle to impart to the spindle in transit in the winding channel a rotary motion in accordance with the direction of advancement of the web and of controlled speed to obtain a first winding tension lower than a subsequent winding tension, in order to reduce a friction between the web and an external surface of the spindle.

10. The apparatus according to claim 9, comprising a transfer device configured to receive extracted spindles from an extractor device and feed the extracted spindles to the rewinding machine for an execution of a new winding.

11. The apparatus according to claim 9, wherein the extraction device comprises roll centering means comprising a first fixed inclined surface and a second inclined surface movable between a lowered roll receiving position and a raised roll centering position due to a convergence of the first fixed inclined surface and the second inclined surface.

12. The apparatus according to claim 9, wherein the extraction device comprises a gripping unit to hold the spindle to be extracted in position and a sliding pusher to push the wound roll axially and move the wound roll with respect to the spindle until the wound roll is extracted.

13. The apparatus according to claim 9, wherein the spindle is a hollow spindle and the gripping unit comprises an expansion restraint insertable within the spindle and comprising spherical radial protrusions impinging on an inner surface of the spindle.

14. The apparatus according to claim 9, wherein the gripping unit is vertically adjustable to adapt to different heights of the spindle.

15. The apparatus according to claim 9, wherein the extraction device comprises a vertically movable cradle for receiving the extracted spindle and lowering down to a chute below the spindle towards a transfer channel for outputting the spindles from the extractor device.

16. The apparatus according to claim 9, wherein the transfer device comprises a repository for accumulating extracted spindles.

17. The apparatus according to claim 16, wherein the transfer device comprises a plurality of supports for the spindles moved by a chain or belt transfer apparatus mounted on pulleys and moved by motors along a portal support structure extended from a spindle receiving position to the repository.

18. The method according to claim 2, wherein the first winding step comprises a step of rotating the central spindle according to an advancement of the paper web to be wound.

19. The method according to claim 2, wherein the winding step comprises a preliminary step of applying glue to the central spindle.

20. The method according to claim 3, wherein the winding step comprises a preliminary step of applying glue to the central spindle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other advantages will be better understood by each technician in the field, from the description that follows and from the attached drawings, given as a non-limiting example, in which:

[0015] FIG. 1A show a side view detail of a rewinding unit of an apparatus according to the invention;

[0016] FIGS. 1B and 1C show respectively a side view and a partial section in front view of a detail of the means for cutting the web in a rewinding machine;

[0017] FIG. 2 shows in perspective view an apparatus according to the invention;

[0018] FIGS. 3A-3B show a detail of two successive configurations in a first operational phase of the apparatus extraction device in FIG. 2;

[0019] FIGS. 4A-4D show a detail of a second operational phase of transfer of the log wound on the hollow spindle in the apparatus of FIG. 2;

[0020] FIGS. 5A-5C show a detail of a third operational phase of log extraction in the apparatus of FIG. 2;

[0021] FIGS. 6A-6F show a detail of a preferred form of making a hollow chuck gripping head that can be used in an apparatus according to the invention;

[0022] FIG. 7 shows a detail in the side view of the extraction unit of the apparatus in FIG. 2;

[0023] FIGS. 8A-8D show successive moments of the transfer phase of the hollow spindle from the extraction unit of FIG. 7;

[0024] FIG. 9 shows a detail in the side view of the cyclic transfer unit of the hollow spindle towards the rewinder unit of the apparatus in FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] With reference to the attached drawings, a preferred example of embodiment of an apparatus and a method according to the invention for the production of coreless paper rolls, or logs, is now described.

[0026] In the example shown in the figures, and in particular in FIG. 2, the apparatus includes a rewinding machine M for winding around a spindle 1 of a web 2 unwound by means of drive rollers 50 from a main reel 3 placed upstream of the rewinder M, until the formation of a roll 4 performed by means of a winding unit 40, and subsequent execution of a subsequent cycle of interruption of the web coming from the main reel and new winding.

[0027] Downstream of the rewinder M in the direction of exit of the roll there is an extraction device E configured to receive from the rewinding machine the wound rolls 4 and to extract therefrom spindle 1 to obtain rolls without internal core. Further, downstream of the extractor E in the exit direction of the extracted spindles there is a transfer device T configured to receive from the extractor device E the spindles 1 and to transfer them cyclically to the rewinder machine M for the execution of a new winding.

[0028] According to the invention, the winding of the web 2 around the spindles 1 is carried out with a first winding phase, including one or more turns of the web on the central spindle, with a first winding tension that is less than the winding tension at the steady state of the successive revolutions performed until the completion of roll 4 of the desired size, which tension is controlled in such a way that the friction between the web and the external surface of the spindle is less than what would be induced by the winding tension at steady state and, consequently, the axial force necessary for the extractor to extract the spindle from inside the coil can also be reduced.

[0029] Advantageously, with this solution, the spindle that is extracted, even if it has low mechanical characteristics of tensile strength and yield strength, maintains a substantially rigid behavior without undergoing significant deformation or elongation and can consequently be reused several times in the production cycle while maintaining the required functionality.

[0030] In different examples of actuation, it will therefore be possible to adjust the first winding tension also in relation to the mechanical characteristics of the spindle in order to ensure its rigid behavior during extraction. In addition, the first winding tension can be controlled in different ways, also depending on the type of rewinding machine used.

[0031] For example, it will be possible to adjust the relative speed of rotation of the web winding rollers around the spindle compared to the speed of feeding the web that is carried out by the reel through the drive rollers.

[0032] FIG. 1A shows a particularly advantageous example of the construction of the rewinding machine M, in which the web 2 is fed by the main reel 3 and passes in succession first through a perforating unit 31 for the creation of transversal perforation lines of the web, then through a drive unit 50 including an upper roller 28 and a lower roller 29 which control the advancement of the web 2, and finally a winding unit 40 which provides for the creation of the logs or rolls 4 by winding the web on a succession of spindles to be wound 1 coming from a feed 10.

[0033] In the example described, the winding unit 40 includes an upper winding roller 5 wound by the web 1, a lower winding roller 16, and a pressure roller or press 6, all in contact with the roll 4 being formed and at least one of which is preferably motorized and controlled independently of the motorization of the drive unit 50.

[0034] In the example described, the press roller 6 is carried by an arm 19 rotating around an axis 17 by means of an actuator 18 (e.g. a linear hydraulic piston) in order to approach log 4 on command and control its winding parameters, e.g. diameter and softness.

[0035] Finally, downstream of the winding unit there is a chute 20 for the expulsion of the wound log 4 towards the extractor device E.

[0036] During the winding phase, the paper film passes through the upper and lower rollers of the drive unit 50 consisting preferably of a smooth roller 28 and a rough roller 29, the rotation speed of which determines the speed of the feed of the web 1 through the machine.

[0037] Downstream of the drive unit, the web passes through a spindle exchange channel 15 which extends in the direction of the spindle transit between a section 11 of first contact of the spindles with the paper web and a position P in which the growth of the roll 4 takes place by the action of the winding unit 40. In particular, the spindle comes into contact with the upper take-up roller 5 at a section 12 of channel 15 downstream of the first contact section 11 with the web and stops in the growth position P also in contact with the lower roller 16 and the press 6.

[0038] In order to feed the spindles to the rewinding machine M, a spindle feeding ramp 10 1 is converging into channel 15, which ramp includes mobile shelves 32 driven by a chain 33 and driven by a pulley 21 driven by a motor 51. A gluing unit 22 can also be placed along ramp 10 for the deposition along the spindles of one or more strips of glue intended to hold the initial flap of the ply 2 in the subsequent first winding around the spindle 1.

[0039] In correspondence with the exchange channel 15 there are also means of handling the spindles 1 which determine a rotation of the spindles in accordance with the direction of the web 1 and with the same peripheral speed of the web at least when the spindles come into contact with the web.

[0040] Advantageously, the rotary motion imparted to the spindles allows a uniform winding of the web 2 in the first turns, already upstream of the first contact with the upper winding roller 5.

[0041] Preferably, the means of handling can include a distribution of movable belts 41 in contact with the spindles in their direction of advancement towards the upper winding roller.

[0042] In the example described, there is also a contrast plate 40 below which the belts 41 can slide, arranged along the path of approach of the spindles to the take-up roller 5 and positioned adjacent to the lower horizontal tangent of the upper take-up roller 5.

[0043] Preferably, the belts 41 are underpinned by the tension desired by pulleys 43 supported by arms 48 driven by an actuator, for example a hydraulic actuator 49, and are moved in rotation by roller 5 being housed concealed in corresponding circumferential grooves 42 so as to be overflow or slightly recessed with respect to the surface of the roller 5 itself (FIGS. 1B and 1C).

[0044] Advantageously, with this it is possible to control the rotation speed of the spindle to obtain a first winding tension lower than the winding tension at steady state in order to reduce the friction between the web and the outer surface of the spindle, and therefore the axial force required for the subsequent extraction of the spindle from the finished coil.

[0045] In the operation of the winding machine, when the log or roll 4 being formed has reached the desired winding diameter or length, the exchange phase begins with the introduction of a new spindle from the transport device T during the winding phase.

[0046] The exchange phase is thus started and a pusher 23 begins to move by rotating around an axis 24 and comes into contact with the stationary spindle 1 which may have already passed through the gluing unit 22 where it has received the glue necessary to take the paper film and start the new winding.

[0047] Before the core comes into contact with the winding rollers, the first winding of the web on the new core is preferably carried out pneumatically by sending a blade of air emitted towards the web by a blower 26 placed close to the upper winding roller 5 for its entire width and which push the web onto the spindle entering the exchange channel.

[0048] Pusher 23 then takes delivery of the spindle from ramp 10 and brings it into the exchange channel 15.

[0049] With the solution described, when the spindle 1 pushed by the pusher 23 has reached the first contact section 11 with the web at the entrance of the exchange channel 15, it also comes into contact with the moving belts 41 which cause it to rotate in agreement and with the same peripheral speed of the web, causing the first winding of the paper film coming from the drive unit, which adheres to the gluing areas, if any, already created on core 3 by the gluing unit 22.

[0050] In this phase, an interruption of the continuity of the web is also foreseen, obtained by breaking the web, typically along a transverse perforation line created by the perforation group 31.

[0051] Preferably, the interruption of the continuity of the web is carried out immediately after the first gluing of the final flap of paper of an already wound roll on the new incoming spindle, such that while the final flap of the wrapped paper on the finished roll 4 is recalled and completes the previous winding, the initial flap of the paper of the new winding is already wound on the rotating spindle 1.

[0052] In the example described, the interruption of the web is carried out by sending a blow of pressurized air which is emitted from nozzle 26 when the incoming spindle is in the first contact section 11 and blocks the web 2, so that the sending of air causes an overtension that breaks the paper web.

[0053] The web interruption phase can in any case be carried out according to principles and techniques other than the use of an air blade as described above, for example by mechanically inducing a state of tension in the web at the end of the winding phase, by means of a web braking or a positive differential of the speed of movement of the web between the winding unit and the drive unit that induces a state of tension in the paper web.

[0054] For example, with reference to FIGS. 1B and IC the interruption of the web can be carried out by temporarily contrasting with the web and with the lower plate 40 of the blower 26 by a pad 46 placed at the end of the pusher 23 for the entire width of the web and which can be advantageously provided with grooves 49 in correspondence with the belts 41, so as to compress and block the web 2 without interfering with the rotation of the straps themselves.

[0055] With reference to FIGS. 3A-6F, a preferred embodiment of the extraction device E for extracting the spindles 1 from the formed coils 4 coming, for example, from a chute 20 for the exit of the coils from the rewinding machine M, is now described.

[0056] In the example described, roll 4 is accommodated by a centering element consisting of a first fixed inclined surface 52 and a movable inclined surface 53 between a lowered position (FIG. 3A) at the arrival of the roll and a raised position (FIG. 3B) in which the moving surface 53 is raised by a kinematic mechanism 54 driven by an actuator 55 and the roll is centered as a result of the convergence of the surfaces 52, 53.

[0057] With reference now to FIGS. 4A-4D, the extractor E also includes a pusher 56 sliding along a crossbar 57 parallel to the axis of the coil 4 centered between surfaces 52, 53 and extended at least for the length of the roll itself being processed between a free end 58 and an engagement end 59 arranged in correspondence with a gripping unit 60, which will be later described in more detail with reference to FIGS. 6A-6F.

[0058] After the centering of the roll 4, the pusher 56 which is initially placed beyond the free end 58 (FIG. 4A) is moved towards the gripping unit 60 by a motor, not shown, in order to push the roll and to move it axially up to the position in FIG. 4B in which the spindle 1 is engaged by the unit 60, after which the pusher 56 can be lifted along a vertical guide 61 (FIG. 4C) to get out of the overall dimensions of the roll 4 and finally, it can move together with the guide 61 along the crossbar 57, for example by a chain or belt 62 driven by a motor 63 until it is placed beyond the first end 59 of the roll 4 near the gripping unit 60.

[0059] With reference to FIGS. 6A-6F, a possible construction form of the gripping head 60 and its engagement with the spindle is described in greater detail. In the engagement position of FIG. 4B, the roll 4 has been moved from the pusher to the gripping unit 60 in the direction indicated by the arrow.

[0060] In the case described, spindle 1 is a hollow spindle and the gripper unit 60 includes a holding device consisting in the example illustrated of an expansion head 64 possibly also equipped with chamfers in its insertion front part.

[0061] As shown in the figures, the head 64 can be operated by an actuator 65 to protrude axially from a containment sleeve 66 and allow spindle 1 to move towards unit 60 until the expansion head 64 penetrates inside the spindle cavity (FIG. 6A) and then moves back inside the sleeve together with the portion of the spindle protruding axially from roll 4 (FIG. 6B).

[0062] Advantageously, the head 64 of the gripper unit 60 is mounted by means of a vertical adjustment 70 on a frame 71 in such a way that its position can be adjusted vertically, as shown in FIG. 5A, and adapt to different sizes of the roll 4 and therefore of the spindle 1.

[0063] In this position, the expansion head 64 is actuated to exert pressure on the inner surface of the spindle cavity, e.g. by means of radial elements or blocks 68 with conical geometry forced to expand by the axial displacement of a taper 67 engaged internally to the dowels and driven by an actuator 69 to force the blocks 68 to diverge radially and force against the walls of the spindle 1.

[0064] Preferably, it is alternatively possible to provide that the expansion head 64 engages with the spindle by means of spherical radial protrusions 88 of the blocks 68, schematized in FIG. 6B, interfering with the internal surface of the spindle.

[0065] In this position (FIG. 6C) spindle 1 is then blocked by the gripping unit 60 and the pusher 46, now positioned in correspondence with the gripping unit 60 as also shown in FIG. 5B, can press as described above on roll 4 and extract it from the spindle (FIG. 6D, FIG. 5C) to direct it towards a deposit D of the coreless rolls thus produced.

[0066] At the end of the extraction step, the taper 67 of the head 64 can then be returned to the previous axial position in order to free the blocks 68 that disengage from spindle 1 (FIG. 6E) and the expansion head 64 is advanced again to free the spindle from the sleeve 66 (FIG. 6F). In a preferred way of actuation, the extraction step of spindle 1 from the gripping unit 60 is aided by a cradle 71, visible in FIG. 5A and better in FIG. 7, placed below the centering surfaces 52, 53 and which is equipped with a vertical motion to get close and receive the spindle 1 in order to support it after the roll has been extracted from it.

[0067] Preferably, the cradle 71 is also equipped with suction points 72 through which the spindle is held while the gripping head 64 is axially retracted and which, although in a retracted configuration, could offer resistance to the extraction of the hollow spindle.

[0068] FIGS. 8A-8D show the succession of operations that are performed after the complete extraction of the roll from spindle 1 and which include the support of the spindle by the cradle 71 in the high position, and the progressive lowering of the cradle 71 (FIG. 8B) until it is released on the chutes 74 below (FIG. 8C) which determine the sliding of the spindle towards a transfer channel 74 (FIG. 8D) through which the spindles 1 leave the extractor device E to be sent to the transfer device T according to the circular diagram shown in FIG. 2.

[0069] FIG. 9 shows a preferred embodiment of a transfer and accumulation device T according to the invention, including at the inlet a channel 75 which receives the spindles from the transfer channel 74 of the extractor device and deposits them on a chute 76 through which the spindles feed by gravity a chain transfer apparatus 77, o belts, mounted on pulleys 86.

[0070] In the example illustrated, the chains 77 carry a plurality of supports 78 for the spindles and are moved by motors 79 along a portal load-bearing structure 80, which ends in a deposit D formed by a chute 81 in which the spindles are accumulated waiting to be conveyed through an underlying channel 82 towards a corresponding inlet channel 83 of the rewinding machine M for the continuation of the work cycle.

[0071] The apparatus has been described with reference to preferred embodiments, which may have equivalent alternative forms for the implementation of the operational steps of the method of invention and in particular of the three main steps of: [0072] winding of the web on the central spindle including a first phase carried out at a tension lower than the winding tension at steady state until a roll of wound paper is formed.

[0073] In different forms of implementation of the method, the first phase of winding may or may not involve an initial gluing of the web on the spindle and/or the use of air blows to push the ply onto the spindle and may be prolonged for one or more rounds of winding. The first winding tension can be controlled by controlling the speed of the web feed and the movement or rotation of the spindle. [0074] extraction from the roll wound by the spindle by applying a relative axial force of extraction between the roll and the spindle.

[0075] In preferred forms of implementation of the method, the extraction phase can be carried out by holding the spindle by interference with the internal surface of a portion of the hollow axial end of the spindle. [0076] transfer of the extracted spindle to a new winding phase.

[0077] In preferred forms of implementation of the method, the transfer phase of the spindles takes place cyclically by recirculating the extracted spindles and may include a phase of accumulation of a number of extracted spindle to be sent to a new winding phase.

[0078] The present invention has been described according to preferred forms of realization, but equivalent variants can be conceived without leaving the scope of protection of the invention.