ES2744184T3 - Rewind machine and procedure to produce reels of web material - Google Patents

Abstract

Automatic continuous peripheral rewinding machine (2) for producing coils (L1) of web material (N) wound around winding cores (A1, A2), comprising: a first winding cradle (6) formed between a first winding roll (1), a second winding roll (3) and a third winding roll (7); the first winding roll (1) and the second winding roll (3) defining a light (5) through which the winding cores (A1, A2) pass with the web material (N) being wound around thereof; a second winding cradle (10) formed between the first winding roller (1), the second winding roller (3) and a fourth winding roller (8); the third winding roller (7) being placed upstream of the light (5) and the fourth winding roller (8) being placed downstream of the light (5), with respect to the direction of supply of the winding cores ( A1, A2) through light; characterized by a running surface (19) extending around the first winding roll (1) and defining a winding core feed channel (21), between the running surface (19) and the first winding roll (one); the running surface (19) being configured and arranged with respect to the first winding roll (1) in such a way that the winding cores (A1, A2) are fed by rolling in contact with the running surface (19) and with the web material (N) entrained around the first winding roll (1).

Description

DESCRIPTION

Rewind machine and procedure to produce reels of web material.

Technical field

The present invention relates to processes and machines for producing reels of web material, in particular, although not exclusively paper reels, in particular tissue paper, for example, toilet tissue rolls, tea towels or the like.

State of the art

In the field of papermaking, in particular for the production of rolls of toilet tissue, kitchen paper or the like, large spools (primary reels) of tissue paper that come directly from the continuous production machine are wound. These large reels are unwound and subsequently rewound to produce rolls or reels of smaller diameters, corresponding to the diameters of the final product destined for the market. These coils have an axial length equal to a multiple of the finished roll intended for distribution and sale and are subsequently cut by cutting machines to obtain the final product intended to be packaged and sold later.

To produce reels of web material, modern rewinding machines provide for the use of winding rollers which, in various combinations and arrangements, and with an appropriately controlled rotation, allow reels to be produced automatically in a rapid sequence through a feed Continuous band material. At the end of the winding of a reel, the reel must move away from the winding area and the web material must be sectioned (by cutting, tearing or the like), to allow the winding of a rear reel to begin. Normally, the winding takes place around winding cores, usually although not exclusively composed of cardboard, plastic or other suitable similar material. In some cases, the winding takes place around removable and recyclable mandrels, that is, they are removed from the completed reel after the winding is completed, to be reinserted into the rewind machine in order to wind a rear reel.

In winding machines of more modern design, the winding movement is conferred to the coils that are being formed by contact with two or more rollers rotating at a controlled speed. These rewinding machines are called peripheral or surface rewinding machines, since the winding movement is conferred peripherally through the contact between the surface of the winding rollers and the surface of the coils being formed. Examples of automatic continuous surface rewinding machines of this type are disclosed in US Patent No. 5,979,818 and in other patents of the same family, and in the patent documents cited in this patent. In WO-A-2011/104737 and in WO2007 / 083336 an improvement is described with respect to the machine described in this US patent. In these prior art winding machines, the sectioning of the web material is carried out by means of a sectioning, tearing or cutting element, which cooperates with a fixed-axis winding roller, around which the web material is fed , and defining, together with a second winding roller, a light to insert the winding cores into a winding cradle.

These machines are also defined as continuous and automatic, since the various stages of the winding cycle of each reel follow one after another automatically, going from the production of one reel to the next, without interrupting the feeding of the material in band and at a speed approximately constant or substantially constant. The term automatic continuous rewinding machine is used in the present description and in the appended claims to indicate this type of machine.

One of the critical stages in automatic continuous peripheral rewinding machines of the type described above consists of the change stage, that is the stage of sectioning the web material, unloading the completed reel and starting to wind a new reel around a new one. winding core inserted in the winding cradle.

Various solutions have been studied to perform these operations automatically and quickly, for example, through the use of winding rollers that rotate at a controlled speed that accelerate and / or decelerate synchronously in order to favor the correct movement. of the completed coils and the new cores. In some cases, tearing systems are provided, in which the web material is sectioned at the end of the winding by means of a speed difference. In other cases, pressurized air systems, suction systems, mechanical systems or the like are used to section the band material.

WO-A-2012/042549 describes a peripheral automatic rewinding machine with four rollers. The use of four rollers, all or at least some of them with moving axles, allows two winding cradles to be defined and more effective control of the reel being formed. In some embodiments described in that document, the reel being formed is always in contact with at least three Winding rollers and in some cases may be temporarily in contact with four winding rollers. This allows particularly effective control of the winding cycle, the reel shape and the winding density to be obtained. In some embodiments, the web material is sectioned by lengthening the path of the web material between two winding rollers. The elongation causes the web material to break, forming the free rear edge of a complete reel and a free leading edge to start winding the rear reel on a new core. Although this machine achieves particularly appreciable results in terms of winding accuracy and operational reliability, there are some aspects that can be further improved. In particular, the correct operation and reproducibility of the winding cycle in some cases may depend on the properties of the material being processed, that is, the web material and / or the winding cores.

Summary of the invention

According to the present disclosure, there is provided a rewinding machine with four rollers, of automatic continuous peripheral type, in which coils of web material are wound in a rapid sequence around winding cores, without interrupting the feeding of the web material , that is, feeding the web material continuously or substantially continuously to a winding head, which comprises, in addition to the winding rollers, also a mechanism for the sectioning of the web material at the end of each winding cycle.

By continuous or substantially continuous feeding, it is meant herein that the web material has a feed rate that is substantially independent of the winding cycle, it being understood that other factors may, even substantially, modify the feed rate of the web material. For example, when a primary reel from which the web material is dispensed must be replaced, or when the web material is broken, it may be necessary to slow down or even stop the feeding of the web material to the winding head. However, this variation in speed or stop does not correlate with the winding cycle of the individual coils.

According to one aspect, an automatic continuous peripheral rewinding machine is provided to produce coils of web material wound around winding cores, comprising a first winding cradle formed between a first winding roller, a second winding roller and a third winding roller The first winding roller and the second winding roller define a light through which the winding cores pass with the web material wound around them. The rewinding machine can also comprise a feed path of winding cores that extends between the first winding roller and the third winding roller. Advantageously, a second winding cradle, formed between the first winding roller, the second winding roller and a fourth winding roller is also provided. The third winding roller is positioned upstream of the light and the fourth winding roller is positioned downstream of the light, with respect to the direction of feeding of the winding cores through the light. The rewinding machine may comprise a rolling surface for the winding cores, which partially extends around the first winding roller towards the third winding roller. An insertion channel, that is to say feed, is defined for the winding cores between the race surface and the first winding roller. In the rewinding machine, a feed path can be defined for the web material that extends between the first winding roller and the third winding roller and between the first winding roller and the second winding roller. The rolling surface is configured and disposed with respect to the first winding roller so that the cores are fed by rolling in contact with the rolling surface and with the web material driven around the first winding roller.

In the context of the present description and the appended claims, in a manner consistent with the meaning given to this term in the field of the conversion of paper and other materials into an endless band, and in particular according to the terminology of machine manufacturers rewind, the term winding roller refers to a motorized roller, that is to say a roller that is rotated positively by means of a motor, to transmit the winding movement to the reel that is being formed by friction between the surface of the roller of winding and the reel, which comes into contact with said winding roller.

The arrangement of the winding rollers is such that it allows, for example, the winding of the web reels by means of a joint action of three winding rollers in contact with the reel being formed. In addition, the particular arrangement of the third winding roller with respect to the insertion path of the cores and the web material, which extends between the third winding roller and the first winding roller, as well as through the light between the The first winding roller and the second winding roller, which separates the first winding cradle with respect to the second winding cradle, can allow the winding rollers to be sized appropriately, to also process winding cores of small diameter.

In advantageous embodiments, the rewinding machine comprises a band material sectioning element configured and controlled to section the band material at the end of the winding of a coil in the second winding cradle. For example, the sectioning element can be configured and controlled to cooperate with the first winding roller.

In some embodiments, the sectioning element is configured and controlled to press the web material against the first winding roller and section the web material generating in the web material a tension greater than the breaking point of the web material .

In some embodiments, the rolling surface extends from an inlet of a feed channel of winding cores to the third winding roller. In this way, the winding cores are inserted into the channel, fed by rolling along said channel and around the first winding roller, the web material being fed into the channel between the first winding roller and the winding core . The path of the winding cores then continues, beyond the insertion channel, between the first winding roller and the third winding roller, to reach the first winding cradle.

In advantageous embodiments, the tread surface has interruptions through which a sectioning element can penetrate the feed channel of winding cores to press the web material against the first winding roller. For example, the rolling surface may be formed by a comb structure, comprising a plurality of shaped laminar elements, spaced apart from each other. The shaped edges of the laminar elements form the rolling surface for the cores. The space between adjacent elements allows the sectioning element to pass through. The sectioning element may comprise one or more pressers that interpose between laminar elements of the comb structure that forms the rolling surface.

In some embodiments, the race surface can be divided into two portions. A first portion may be stationary with respect to a load bearing structure. A second portion, positioned downstream of the first portion with respect to the feed direction of the winding cores along the insertion channel, can be movable together with the third winding roller.

In possible embodiments, at least one of said first winding roller and second winding roller has a movable axis, to control the distance between the first winding roller and the second winding roller and the light dimension between the first roller of winding and the second winding roller. In some embodiments, preferably both the first winding roller and the second winding roller have a movable shaft. The first winding roller and the second winding roller may have shafts that move symmetrically with respect to a centerline plane that passes through the light formed between the first winding roller and the second winding roller.

In other embodiments, the first winding roller may have a stationary axis while the second winding roller has a movable axis to control the dimension of light between the first winding roller and the second winding roller.

The diameters of the four winding rollers may be different from each other. Preferably, it is advantageous that the first winding roller has a larger diameter than that of the second winding roller.

In some embodiments, the movement of the first, second, third and fourth winding rollers during coil formation is controlled such that: a first part of the winding of the coil takes place with the coil in contact with the first roller winding, the second winding roller and the third winding roller; a second part of the coil winding takes place with the coil in contact with the first winding roller, the second winding roller, the third winding roller and the fourth winding roller; A third part of the coil winding takes place with the coil in contact with the first winding roller, the second winding roller and the fourth winding roller.

According to a further aspect, a method is provided for winding a web material and sequentially forming coils of said web material wound around winding cores, comprising the following steps:

disposing four winding rollers defining a first winding cradle between a first winding roller, a second winding roller and a third winding roller, and a second winding cradle between said first winding roller, the second winding roller and a fourth winding roller;

disposing a rolling surface that extends around the first winding roller and forming therewith a feed channel for the winding cores;

feed the web material around the first winding roller;

inserting a first winding core in the feed channel and feeding said first winding core along an insertion path between the first winding roller and the third winding roller and inserting the first winding core in the first cradle of winding

carrying out a first part of a winding cycle of a first coil around a first winding core in the first winding cradle,

transfer the first coil that is forming from the first winding cradle to the inside of the second winding cradle through a defined light between the first winding roller and the second winding roller;

carrying out a second part of a winding cycle of the first coil in the second winding cradle;

at the end of the winding of the first coil in the second winding cradle, insert a second winding core into the feed channel and along the insertion path that extends between the first winding roller and the third winding roller and insert the second winding core in the first winding cradle.

In some embodiments, the method may comprise the steps of inserting the second winding core against the first winding roller by squeezing the web material between the second winding core and the first winding roller, and sectioning the web material between the first coil in the second winding cradle and the second winding core.

The method may comprise the following steps: providing a band material sectioning element; and acting through said sectioning element on the web material to section the web material thus generating a rear edge of the first coil and a leading edge with which to start winding a second coil around the second winding core. The two edges can be generated between the second core and the first coil near the winding end.

In some embodiments, the method may comprise one or more of the following following steps: arranging the rolling surface around the first winding roller, defining an insertion channel for the winding cores between the first winding roller and the surface of rolling, the rolling surface extending from an inlet of the insertion channel for the winding cores to the third winding roller; insert the second winding core into the insertion channel and feed the second winding core by rolling along the insertion channel, in contact with the rolling surface and with the web material driven around the first winding roller, until reach the third winding roller; passing the second winding core between the first winding roller and the third winding roller; Insert the second winding core, with a second coil that is winding around it, into the first winding cradle.

A possible embodiment of the process according to the invention provides the following steps:

a) inserting a first winding core towards the first winding cradle, in contact with the web material dragged around the first winding roller and in contact with the rolling surface;

b) fastening a leading edge of the web material to the first winding core;

c) winding a part of a reel of web material keeping the first winding core in the first winding cradle, and feeding the first winding core towards the second winding cradle;

d) to pass the first winding core, with the coil that is winding around it, through the light between the first winding roller and the second winding roller and transfer the first winding core with the winding being formed around it into the second winding cradle and completing the winding of the web material reel in said second winding cradle;

e) inserting a second winding core towards the first winding cradle, in contact with the web material dragged around the first winding roller and with the rolling surface;

f) sectioning the web material forming a leading edge of web material, by means of the sectioning element and unloading the web material web from the second winding cradle;

g) repeat steps (b) to (f) to form an additional coil around said second winding core, without interrupting the feeding of the web material.

A further embodiment of the process according to the invention may comprise the following steps:

a) arrange the third winding roller in an initial position to receive a first winding core; b) having a first winding core come into contact with the guided web material around the first winding roller and angularly accelerating the first winding core by moving it towards the first winding cradle;

c) fastening a leading edge of the web material to the first winding core;

d) feeding the first winding core between the first winding roller and the third winding roller in the first winding cradle and winding a part of a web of web material keeping the first winding core in the first winding cradle, and feed the first winding core to the second winding cradle;

e) passing the first winding core, with the coil that is winding around it, through the light between the first winding roller and the second winding roller, the third winding roller moving from the initial position towards the light between the first winding roller and the second winding roller following the coil that is being formed and moving in the first winding cradle and towards the second winding cradle;

f) transfer the first winding core with the coil that is forming around it to the inside of the second winding cradle;

g) complete the winding of the web material coil in the second winding cradle;

h) return the third winding roller to the initial position;

i) having a second winding core come into contact with the web material drawn around the first winding roller;

j) sectioning the web material forming a leading edge of web material, by means of the sectioning element with the third winding roller in the initial position, and unloading the web material web from the second winding cradle;

k) repeat steps (c) to (j) to form an additional coil around said second winding core, without interrupting the feeding of the web material.

In a still further embodiment, the method may comprise the following steps: arranging the rolling surface around the first winding roller, the feed channel of the winding cores forming with the first winding roller;

at the end of the winding of a coil, insert a new winding core into the feed channel in contact with the rolling surface and with the web material dragged around the first winding roller, angularly accelerating the winding core in the feed channel;

insert the sectioning element into the feed channel, downstream of the new winding core, causing the breakage of the web material between the new winding core and the coil near the winding end in the second winding cradle.

Brief description of the drawings

The invention will be better understood by following the description and the accompanying drawings, which show practical non-limiting embodiments of the invention. More specifically, in the drawings:

Figures 1 to 5 schematically show a first embodiment of a rewinding machine according to the invention in an operating sequence;

Figure 6 shows a diagram of a motorized center system to guide the winding cores; Figure 7 shows a sectional view according to line VII-VII of Figure 6;

Figure 8 shows the position of the system of Figures 6 and 7 with respect to the grouping of the winding rollers; Y

Figure 9 shows a further embodiment of a rewinding machine according to the present disclosure.

Detailed description of embodiments

Figures 1 to 5 show an embodiment of a continuous peripheral rewinding machine according to the invention and an operating sequence showing in particular the change stage, that is to say the stage of unloading a coil, whose winding has been completed, and Insert a new winding core to begin the formation of a rear coil.

Figures 1 to 5 show the main elements of the rewinding machine, limited to those necessary to understand the concepts on which the invention is based and a mode of operation of the machine. Construction details, auxiliary units and additional components, known and / or that can be designed according to the prior art, are not shown in the drawings or described in greater detail. Those skilled in the art can provide these additional components based on their experience and knowledge of the field of paper conversion machinery.

In summary, in the embodiment shown herein, the machine, indicated as a whole with 2, comprises a first winding roller 1 with a rotation axis 1A, arranged next to a second winding roller 3 having a axis of rotation 3A. Axes 1A and 3A are substantially parallel to each other. Between the two winding rollers 1 and 3 a light 5 is defined, through which (in at least a part of the winding cycle of each coil), a N-band material to be wound around cores is fed of winding A1, A2 around which coils L1, L2 are formed. The path of the web material N extends around the first winding roller 1, partially wrapping it, so that the web material N is in contact with the cylindrical surface of the winding roller 1 for a given contact arc, which may vary during the winding cycle, as will be apparent from the description of the winding process.

As will be apparent from the description hereinbelow, the winding cores also pass through the winding light 5 during an intermediate stage of the winding cycle.

The winding cores A1, A2 are inserted into the machine upstream of the light 5, in a first winding cradle 6, formed by the first winding roller 1, by the second winding roller 3 and by a third winding roller 7. Reference 7A indicates the axis of rotation of the third winding roller 7, substantially parallel to the axes 1A and 3A of the first winding roller 1 and the second winding roller 3, respectively.

The winding of N-band material around the winding cores ends when the winding cores are located in a second winding cradle 10 positioned downstream of the light 5 with respect to the direction of feeding of the winding cores in the winding head. winding formed by the winding rollers. The second winding cradle is formed by the first winding roller 1, by the second winding roller 3 and by a fourth winding roller 8. Reference 8A indicates the axis of rotation of the fourth winding roller 8, which is substantially parallel to the axes of the winding rollers 1, 3, 7. Reference 12 indicates a pair of arms that are pivoted at 12A, which support the fourth winding roller 8. The double arrow f12 indicates the pivoted movement, ie the reciprocating rotation movement of the arm 12 and consequently of the fourth winding roller 8. By moving the support point 12A, the winding roller 8 can move towards or away from the light 5 defined between the first winding roller 1 and the second winding roller 3.

In other embodiments, the fourth winding roller 8 can be carried by a system of slides that move on linear guides, rather than by arms that are pivoted about a pivoted axis. In addition, in this case, the translational movement along the linear guides allows the winding roller 8 to move towards and away from the light 5.

In the present description and in the appended claims, the definition "upstream" and "downstream" in relation to the position of the winding rollers refers to the direction of feed of the web material and the axis of the winding cores, unless otherwise specified.

The third winding roller 7 is provided with a movement towards and away from the winding light 5. For this purpose, in some embodiments the third winding roller 7 is supported by a pair of arms 9 that are pivoted about an axis 9A so that they oscillate, that is to say rotate with a reciprocating movement, according to the double arrow f9 . In other embodiments, not shown, the third winding roller 7 can be supported by slides that move on linear guides, to follow, for example, a rectilinear motion path.

Upstream of the winding light 5, the first winding roller 1 and the second winding roller 3, a core feeder or inserter 11 is arranged, which can be made in any suitable manner and inserts individual winding cores A1, A2 to the first winding cradle, as will be described in greater detail with reference to the sequence of Figures 1 to 5.

The winding cores can come from a "core winding machine", that is to say a machine for forming winding cores, associated with the N-band material conversion line in which the machine is inserted rewind 2, and not shown.

In some embodiments, the rewinding machine comprises a rolling surface 19 for the winding cores. The tread surface 19 can have a more or less cylindrical shape, approximately coaxial with the first winding roller 1 with movable axis, when it is in the position of figure 1. The tread surface 19 can have a step 19g in a intermediate position of its extension. The rolling surface 19 can be divided into a first portion 19A and a second portion 19B, the first one positioned upstream of the second, with respect to the direction of feeding of the web material N.

The rolling surface 19 and the cylindrical surface of the first winding roller 1 form a feed channel 21 for the winding cores A1, A2. When the first winding roller 1 is in the position of Figures 1 to 4, the height of the feed channel 21 for the winding cores may be smaller in the first portion of the feed channel and greater in the second portion of the feed channel. feeding 21. The purpose of this variation in the height of the feeding channel 21 is to facilitate the start of a rolling movement of each new winding core A1, A2, inserted in the feeding channel 21 by means of the inserter or feeder 11, such as will be explained hereinafter. In particular, in the first portion of the feed channel 21, the height of the feed channel, ie the distance between the winding roller 1 and the rolling surface 19, may be smaller than the diameter of the winding cores A1, A2.

In some embodiments, the rolling surface 19 is formed by a comb structure, with a plurality of arc plates arranged side by side, between which free spaces are formed. Through these free spaces between adjacent plates that form the rolling surface 19, a sectional element of the band material N, indicated as a whole with 23, can be inserted. In some embodiments, the comb structure forms the first part 19A of the rolling surface and can be stationary, that is to say fixed with respect to a support structure, not shown. In some embodiments, a second part 19B of the rolling surface may be formed by elements 19C that move with the axis 7A of the third winding roller 7, following the latter's movement.

The elements 19C can also be plates that form a comb structure.

In other embodiments, the surface 19B may be formed by a single arc plate, which extends transversely with respect to the feed movement of the web material, that is to say parallel to the axes of the winding rollers 1, 3, 7.

In some embodiments, the sectioning element 23 comprises a presser, which includes for example a plurality of pressure elements 24. The sectioning element 23 can be provided with a reciprocating rotation movement, about an axis 23A, in parallel approximately to the axes of the winding rollers 1, 3. Reference f23 indicates the movement of the sectioning element 23. Each pressure element may have a pressing block 24A. The pressing block 24A may be composed, for example, of a material that is elastically deformed preferably with a high coefficient of friction, for example, rubber.

In synchronization with the movement of the other elements of the machine, as will be better illustrated hereinafter with reference to an operating cycle, the sectioning element 23 is pressed against the first winding roller 1 to tighten the N-band material between the studs 24A of the pressure elements 24 and the surface of the first winding roller 1. The latter may have a surface with annular strips having a high coefficient of friction and annular strips having a low coefficient of friction . In this context, the terms "high" and "low" are intended to indicate a relative value of the coefficients of friction of the two series of alternating annular stripes. The bands with low coefficient of friction can advantageously be arranged in the areas where the studs 24A of the pressure elements 24 are pressed. Thus, when the web material N is pressed against the first winding roller 1 by means of the elements of pressure 24, tends to stop by means of the plugs 24A and to slide on the annular strips with low coefficient of friction of the first winding roller 1.

Figure 1 shows a final stage of the winding cycle of a first coil L1. As shown in Figure 1, during this stage of the winding cycle of a first coil L1 around a first winding core A1 the coil L1 is located in the second winding cradle 10, in contact with the first winding roller 1, the second winding roller 3 and the fourth winding roller 8. The web material N is fed, according to the arrow fN around the first winding roller 1, through the light 5 between the first winding roller 1 and the second winding roller 3 and is wound on the coil L1 being formed, which is rotated by the rollers 1, 3 and 8 and is thus retained in the winding cradle 10. Reference 27 indicates a guide roller for the N-band material positioned upstream of the winding head defined by winding rollers 1, 3, 7 and 8.

Preferably, the feed rate of the N-band material is substantially constant. Substantially constant means a speed that varies slowly with respect to the speed of winding and as a consequence of factors that are independent of the operations performed by the winding head elements described above, which are controlled to perform the winding cycle, unload the formed coil, insert the new core and start winding a new coil to a constant feed rate of the web material towards the winding roller crush and in particular towards the first winding roller 1.

During the winding of the coil L1, regardless of the change stage, which forms a transition stage in the operation of the machine, the peripheral speeds of the winding rollers 1, 3, 7 and 8 are substantially equal to each other and the various winding rollers rotate all in the same direction, as indicated by the arrows in the drawings. In this case, substantially the same means that the speed can vary in a limited way according to the need to control the winding compactness and the tension of the web material N between the winding roller 7 and the winding roller 8, for example, to compensate the variation in tension that can be caused by the movement of the center of the coil that is forming along the path between the winding rollers.

In some embodiments, this difference between peripheral speeds of the winding rollers can normally be between 0.1 and 1% and preferably between 0.15 and 0.5%, for example, between 0.2 and 0.3%, it being understood that These values are examples and are not limiting.

In addition, the peripheral speeds may vary slightly to cause the forward movement of the coil being formed, as clarified below, so that it passes from the first winding cradle 6 to the second winding cradle 10.

The winding cycle of the coils is as follows.

In Figure 1 the coil L1 in the winding cradle 10 formed by the rollers 1, 3, 8 has been practically completed, with the winding of the required amount of material in the N-band around the first winding core A1. The amount of winding web material can be determined by a winding length. The winding core feeder or inserter 11 has brought a second winding core A2 to the input of the feed channel 21.

Reference C indicates a continuous line or series of glue points applied to the outer surface of the second winding core A2.

Figure 2 shows the beginning of the change stage, that is to say the unloading of the completed coil L1 and insertion of the new winding core A2 in the winding head formed by the rollers 1, 3, 7, 8.

The second winding core A2 is inserted by the winding core feeder or inserter 11 into the feed channel entrance 21 defined between the first winding roller 1 and the rolling surface 19.

The position of the first winding roller 1 at this stage of the winding cycle is such that it is approximately coaxial with the general rolling surface 19 and approximately cylindrical. The distance between the portion 19A of the rolling surface 19 and the cylindrical surface of the first winding roller 1 is slightly smaller than the diameter of the winding core A2. In this way, the winding core A2 entering the feed channel 21 is pressed against the rolling surface 19 and against the web material N driven around the first winding roller 1.

This pressure generates a frictional force between the surface of the winding core A2 and the rolling surface 19, and between the surface of the winding core A2 and the web material N dragged around the cylindrical surface of the first winding roller 1. This ensures that, as a result of the rotation movement of the first winding roller 1 and the feeding of the N-band material, the winding core A2 accelerates angularly, starting to roll along the tread surface 19, pushed by the web material N and the first winding roller 1 against which the web material N is pressed.

Along the second portion 19B of the tread surface 19, the radial dimension of the feed channel 21 can gradually increase, thereby reducing the deformation of the diameter of the winding core A2 and allowing the winding of the web material N to begin around it, with the consequent formation of turns of a new coil.

The step 19G, if provided, can facilitate the initial angular acceleration phase of the winding core A2.

During the rolling movement of the winding core A2 in the feed channel 21, the tail line C applied to the winding core A2 comes into contact with the N-band material, causing the adhesion of the N-band material to the winding core .

At this stage of the winding cycle, the breaking or sectioning of the N-band material also takes place by means of the sectioning element 23. This latter pivot is made against the first winding roller 1, for tightening, with the studs 24A , the web material N against the surface of the first winding roller 1. As the winding rollers 1, 3 and 8 continue to rotate, winding the web material N on the web L1, the web material stretches between the coil L1 and the point of tightening of the web material N against the first winding roller 1 by means of the sectioning element 23.

When the tension exceeds the breaking point, for example, in a perforation line of the N-band material, the latter is broken generating a rear edge Lf, which is wound on the coil L1, and a leading edge Li, which is wound on the new winding core A2. The front and rear edges Li and Lf are shown schematically in Figure 3. In this embodiment of the winding process, when the sectioning of the N-band material is performed, the winding core A2 passes through the dimension portion minor radial of the insertion channel 21 of the winding cores A2, that is in the step 19G. In other embodiments, the sectioning of the N-band material can take place before or after the passage of the winding core A2 above the step 19G.

In some embodiments, the winding can start without the use of the tail C, for example, by electrostatically charging the material in the N-band and / or the winding core A2, or using a suction system, optionally inside of the winding core A2, which can be provided with suction holes. In other embodiments, the winding can start with the help of air jets. In still other embodiments, the start of the winding can be obtained or facilitated through a proper control of the movement of the sectioning element 23. For example, the sectioning element can be controlled to form a loop of material in N-band, which is coil around the winding core.

While in the sequence of Figures 1 to 5, the movement of the sectioning element 23 is an reciprocating movement, in other embodiments the movement of the sectioning element 23 can always occur in the same direction, for example, in clockwise direction in the drawings. The speed of the sectioning element can be controlled to cause breakage or sectioning of the web material between the clamping point of the web material N by the plugs 24A and the coil L1, for example, by rotating the sectioning element 23 with a speed such that the studs 24A are fed at a lower speed than the peripheral speed of the first winding roller 1. In other embodiments, the speed of the studs 24A may be greater than the peripheral speed of the first winding roller 1. In In this case, breakage or sectioning of the N-band material can take place between the clamping point of the N-band material by the studs 24A and the tightening point of the N-band material between the first winding roller 1 and the new one winding core A2.

In other embodiments, not shown, the sectioning element can be configured differently, and, for example, perform the cutting of the web material using a blade that cooperates with a counter knife on the first winding roller 1. In still others embodiments, the sectioning of the web material can be obtained with a sectioning element housed in the first winding roller 1 or between the latter and the path of the web material N, configuring and controlling the sectioning element to section the material in belt acting from the side of the web material N oriented towards the winding roller 1.

Figure 4 shows the subsequent stage, in which the second winding core A2, rolling along the rolling surface 19, leaves the rolling surface 19 and comes into contact with the cylindrical surface of the third winding roller 7, which is located at the end of the insertion channel 21 for the winding cores.

The third winding roller 7 can be provided with a series of annular grooves 7S, in which the ends of the plates forming the terminal part 19B of the rolling surface 19 are inserted. In this way, the winding core A2 is gently transfers from the rolling surface 19 to the surface of the third winding roller 7.

Rolling on the surface of the third winding roller 7 and remaining in contact with the web material N conducted around the first winding roller 1, the winding core A2, or more precisely the new coil L2 that begins to form around the it also comes into contact with the second winding roller 3, as shown in Figure 4. Therefore, in practice the travel of the winding cores extends between the first winding roller 1 and the third roller of winding 5 and through the light 5 between the first winding roller 1 and the second winding roller 3.

To allow the feeding of the winding core A2 along the feed channel 21, the sectioning element 23 is rotated around the axis 23A until it exits the feed channel 21. The tail C (or other means or element to start the winding) has caused the adhesion of the N-band material to the winding core A2, so that the web material begins to wind over the winding core A2 starting the formation of a second coil L2 while the core is fed by rolling to along channel 21.

During the operations described above, the first coil L1 starts the ejection movement from the second winding cradle 10, for example, as a result of a variation of the peripheral speeds of the rollers 1, 3 and 8. In some embodiments, the fourth winding roller 8 can be accelerated and / or the second winding roller 3 can be decelerated to cause the coil L1 to move away from the second winding cradle 10 towards a discharge ramp 31. The fourth winding roller 8 moves upwards to allow the passage of the coil L1 towards the discharge ramp 31.

In Figure 4, the second winding core A2 is located in the first winding cradle 6 and is in contact with the first winding roller 1, the second winding roller 3 and the third winding roller 7 and the second winding L2 It is forming around it. The completed coil L1 is discharged on the ramp 31. The second winding core A2 passes through a light or a defined space between the first winding roller 1 and the third winding roller 7, before coming into contact with the second winding roller 3. Subsequently, as described below, the winding core A2 with the coil L2 being formed around it also passes through the light 5 between the first winding roller 1 and the second winding roller 3.

The formation of the second coil L2 continues through the feeding of the N-band material around the new winding core A2 and the consequent increase in the diameter of the new coil L2. The third winding roller 7 can move due to the movement of the arms 9 around the support point or the axis 9A, after increasing the diameter of the second coil L2. The portion 19B of the rolling surface 19 can follow the movement of the third winding roller 7, so as not to obstruct the movement of the latter towards the light 5 between the first winding roller 1 and the second winding roller 3.

After a part of the winding cycle has been performed in the cradle 6, the coil L2 moves to the second winding cradle 10 in which the winding of the coil is completed. For this purpose, it is necessary to pass the coil L2 through the light 5. To do this, in some embodiments one or preferably both of the winding rollers 1 and 3 can be supported by the respective arms 1B, 3B so that pivot around the oscillation axes 1C, 3C.

As can be seen in Figure 5, which shows an intermediate stage of the passage from the winding cradle 6 to the winding cradle 10, the distance between the centers of the winding rollers 1 and 3 is gradually increased, for example by swinging the arms 1B, 3B. In other embodiments, the winding rollers 1, 3 can be carried by means of slides which are provided with a translation movement, instead of a pivoting or rotating movement.

Whatever the mechanism used to modify the distance between the centers of the winding rollers 1 and 3, its movement away from each other (figure 5) allows the coil L2 to pass through the light 5 and enter the cradle of winding 10.

In some embodiments, during this stage the third winding roller 7 can gradually move towards the second winding cradle 10, accompanying the coil L2. In this way, the winding continues to take place in contact with at least three winding rollers 1, 3, 7.

The fourth winding roller 8, which was raised to allow the growth of the coil L1 followed by the discharge thereof towards the ramp 31, is returned to the light 5 until it comes into contact with the coil L2, which is fed through of the light 5. During a part of the winding cycle the coil L2 may be in contact with all four winding rollers 1, 3, 7 and 8.

The third winding roller 7 can move towards the light 5 following the coil L2 until it is made to pass beyond the light between the rollers 1 and 3. From this point, the coil L2 can be in contact only with the rollers 1, 3 and 8 and finish winding in the second winding cradle 10.

The feeding movement of the axis of the coil L2 can be obtained in a suitable manner with a control of the movement of the winding rollers, which, by modifying the mutual position of their axes, move the coil L2 to the interior of, and through, the minimum distance zone between rollers 1 and 3. For example, the movement can be obtained by pushing the coil with the third winding roller 7. In some embodiments the movement of the coil can be facilitated, supported or influenced by a temporal variation of the peripheral speeds of the winding rollers, for example, decreasing the peripheral speed of the second winding roller 3 for a short period.

While the embodiment shown in Figure 5 includes a stage in which the coil L2 is in contact with the four winding rollers 1, 3, 7 and 8, in other embodiments the third winding roller 7 may lose the contact with the coil L2 before it passes through the light 5, beyond the point of minimum distance between the winding rollers 1 and 3, and comes into contact with the fourth winding roller 8. However, in the form of embodiment shown, better control of the coil is obtained in the various stages of formation, since that the coil is always in contact with at least three winding rollers.

The time during which the second winding core A2 remains in the position of Figure 5, that is in the winding cradle 6, can be controlled simply by acting on the peripheral speed of the winding rollers 1, 3 and 7 and / or about the position of the rollers. The second winding core A2 will remain substantially in this position, without additional feeding, for the entire time during which the peripheral speeds of the winding rollers 1, 3 and 7 remain the same. As mentioned above, a further advance is obtained, for example, by decelerating the second winding roller 3. Therefore, it is possible to establish the amount of material in the N-band that is wound around the winding core A2 as desired, retaining the latter and the second coil L2 that forms around it in the winding cradle 1, 3, 7 for the desired time.

Once the coil L2 is located in the second winding cradle 10, the winding of the second coil L2 continues until it reaches the state of Figure 1. The third winding roller 7, which can move towards the light 5 to accompany The movement of the coil L2 through the light in the second winding cradle 10, can return to the initial position of Figure 1, in which it cooperates with the sectioning element 23.

In some embodiments, the structure of the elements of the rewinding machine is such that the path followed by the center of the winding cores A1, A2 from the moment they come into contact with the three winding rollers 1, 3 and 7 until such time as the coil begins to discharge between rollers 1, 3 and 8, losing contact with the winding roller 7, is substantially rectilinear. This allows a more regular winding and facilitates the use of centers that can be inserted at opposite ends of the winding cores in order to improve the control of the rotation and feeding movement of the core and the coil during the winding cycle, combining the peripheral winding technique with an axial or central winding, as described, for example, in US Patent No. 7,775,476 and in US-A-2007/0176039.

With the described arrangement of the four winding rollers and the path of the winding cores between the first winding roller 1 and the third winding roller 7, it is possible to provide the first and second winding rollers 1, 3 with a diameter relatively large, and in such a way that an intermediate support is not required, even when the winding cores have a small diameter. However, the control of the small diameter winding cores is also guaranteed with winding rollers 1, 3 of a relatively large diameter, since the third winding roller 7 can be provided with a smaller diameter. The lower flexural stiffness of the third winding roller 7 due to the smaller diameter of this roller can be compensated using one or more intermediate supports. In some embodiments, the third winding roller 7 can be associated with a support and reinforcement beam, which extends parallel to the axis 7A of the third winding roller 7, in an area where this beam does not interfere with the path of the material in band N and with the coils L1, L2 that are forming. The beam can be positioned, for example, in the elements 19C, or in a diametrically opposite position with respect thereto, that is to say in an area where the third winding roller 7 does not cooperate with the web material N and / or with the coil L1, L2 that is forming.

In the embodiment shown in the attached figures, the first winding roller 1 and the second winding roller 3 have substantially the same diameter and both are mounted with movable shafts to increase and decrease the dimension of the light 5, through which passes the coils that are forming around the respective winding cores. In other embodiments, the winding roller 1 of a different diameter may be provided, for example, larger than that of the winding roller 3. By increasing the diameter of the winding roller, the support system of said roller can be simplified, since a greater diametral dimension implies greater flexural rigidity.

In addition, in some embodiments, only one of the two winding rollers 1 and 3 can have a movable axis, while the other has a fixed axis. In this way, the number of actuators required for the movement of the various elements of the rewinder is reduced and the law to control the movement of the winding rollers is simplified. If the two winding rollers 1 and 3 have different diameters, it is advantageous that the larger diameter winding roller, for example the winding roller 1, has a fixed axis, while the smaller diameter winding roller has a moving axis . In this configuration, the winding sequence of the web material around the winding core does not change. The winding starts in the winding cradle 6 and ends, after the passage of the coil that is winding through the light 5, in the second winding cradle 10.

In still further embodiments, the winding rollers 1 and 3 can both be mobile, but they can perform asymmetric movements.

In some embodiments, the rewinding machine described above may be provided with a system of motorized centers, which are coupled with, guide and control the winding cores for at least a part of their movement between the winding cradle 6 defined by the rollers 1, 3 and 7, upstream of light 5, and the winding cradle 10 formed by rollers 1, 3 and 8, downstream of light 5.

The center system may comprise, on each side or side of the machine, a center 101 for engaging with the respective end of a winding core A1, A2 that is inserted into the winding area. Figures 6 and 7 show one of these centers and the related operating mechanism.

The center 101 may have a rod 103 ending in a head 105. The head 105 may have a mechanism for engaging with the tubular winding core. In some embodiments, the head 105 can be coupled with the winding core by inserting therein. The head 105 may have expandable elements, to be torsionally coupled with the winding core. In some embodiments, the expandable elements comprise expandable annular elements 107, for example, pneumatically expandable, through a compressed air supply system. Compressed air can be transported through conduits 109.

The center 101 can be provided with a translation movement according to the arrow f101, parallel to the longitudinal axis X X of the center.

An actuator, for example a piston-cylinder actuator 111, can be used to control the reciprocating movement according to the double arrow f101. This movement allows the heads 105 of opposite centers 101 on the two sides of the machine to move towards each other, until the heads 105 are coupled with the ends of the respective winding core A1, A2 which is located in the winding area . Heads 105 may be made to penetrate partially or totally at the ends of the winding core.

As can be seen in particular in Figure 6, each center 101 may be provided with a motor 115, for example an electronically controlled electric motor, which rotates the respective center 101 around its X-X axis. The movement can be transmitted from the engine 115 to the center 101 by means of a belt 117, for example a toothed belt. The toothed belt 117 can be driven around a pulley 119 torsionally attached to the rod 103 of the respective center 101. More in particular, the pulley 119 can be fitted on a sleeve 121, inside which the rod 103 of the center 101 can slide along the double arrow f101, the sleeve 121 being torsionally coupled to the rod 103, for example through a grooved profile or Similar. The sleeve 121 can be supported by means of bearings 123 inside a bush 125 which can be carried by means of a slide 127.

The slide 127 can be mounted on stationary guides 129, that is to say in solidarity with the load bearing structure of the rewinding machine. In this way, the slide 127 can be moved along the double arrow f127 in the direction defined by the guides 129. In some embodiments, the rectilinear reciprocating movement according to f127 can be conferred by means of a motor 131, for example, an electronically controlled electric motor. The electric motor 131 can cause the oscillation of a crank 133, from which the movement is transmitted through a connecting rod 135 to the slide 127, the connecting rod 135 being articulated in 135A with the slide 127 and in 135B with the crank 133.

The movement according to the double arrow f127 can be substantially rectilinear and parallel to the movement of the center of the winding core A1, A2 when it passes from one to the other of the two winding cradles defined by the sets of three rollers 1, 3, 7 and 1, 3, 8, during the winding procedure described above. The centers 101 can be coupled with the winding core A1, A2 when it is in the winding cradle 6 upstream of the light 5 and can be disengaged from it when the coil L1 is almost finished, thus allowing the latter to discharge according to the previous description with specific reference to the stage shown in figures 3 and 4.

During the movement according to the double arrow f127, and more particularly during the upward movement stage (in the figure) of the centers 101, they accompany the winding core while the diameter of the coil L1 grows, while the motor 115 confers , by means of the belt 117, a rotation movement to the centers 101, which is transmitted to the winding core and therefore to the coil being formed, as a result of a torsional coupling between the heads 105 of the centers 101 and the winding core A1, A2. The rotation speed conferred by the motor 115 can be controlled, so that it is consistent with the peripheral speed of the coil L1 being wound.

The use of the centers 101 allows a better control of the winding and the advance of the coil L1 from one to the other of the two winding cradles 6, 10 and through the light 5 during all the stages of the winding cycle.

In the embodiments shown in Figures 1 to 8, the first winding roller 1 and the second winding roller 3 have substantially the same diameter and both can have a movable shaft, to favor the passage of the core and the band in the first winding stage from the first winding cradle 6 to the second winding cradle 10. In other embodiments, the first winding roller 1 and the second winding roller 3 can have different diameters and preferably the first winding roller 1 may have a diameter greater than that of the second winding roller 3.

In possible embodiments, one of the winding rollers 1 and 3 may have a fixed axis and the other a movable axis.

Preferably, the first winding roller 1, around which the web material N is wound and guided, can have a fixed axis and have a diameter greater than that of the second winding roller 3.

Figure 9 shows such a configuration. The same numbers indicate equal or equivalent parts to those described with reference to Figures 1 to 8. In particular, the four winding rollers are indicated with 1, 3, 7 and 8. A channel is formed around the first winding roller 1 21 for the insertion of the winding cores A1, A2. The channel is delimited by the cylindrical surface of the first winding roller 1 and by a rolling surface 19 that extends around the first winding roller 1 and towards the third winding roller 7. The winding cores are inserted in the channel 21 so that they are in contact with the rolling surface 19 and with the web material N dragged around the first winding roller 1. The rolling surface 19 can have a kind of intermediate step, as indicated in 19G, to facilitate the angular acceleration of the winding core and the grip of the web material after the sectioning caused, in the same manner as described above, by means of a sectioning element 23 of the web material N. This sectioning element 23 of the material in belt cooperates with the first winding roller 1 by squeezing the web material between the first winding roller and one or more presses 24A os by the sectioning element 23.

The axis of rotation 1A of the first winding roller 1 is stationary with respect to the load bearing structure of the machine 1, to make the feeding of the material in band N to the light 5 between the first winding roller 1 and the second Winding roller 3 is more stable and more easily controlled.

In this embodiment, the second winding roller 3 has a diameter substantially smaller than the diameter of the first winding roller 1. For example, the diameter of the second winding roller 3 may be less than half the diameter of the first winding roller. winding 1. The second winding roller 3 can be supported by lateral stringers 4, as schematically indicated in Figure 9. Between the lateral stringers 4 intermediate supports can be arranged, which support the second winding roller 3 in intermediate positions between the extremes of the latter. In this way, it is possible to design the second winding roller 3 with a small diameter.

To obtain sufficient rigidity of the second winding roller 3, the stringers 4 and any intermediate support can be attached to a cross beam 14.

The axis 3A of the second winding roller 3 can be mobile and pivot about a pivot axis defined by a pivot point 16 of the beams 4 to the load bearing structure of the rewinding machine 2. The pivoting movement of the second winding roller 3 can be controlled by a motor 18 associated with a crank 20. A connecting rod, which is also pivoted in 22B with respect to the respective stringer 4, can be pivoted in 22A with respect to the crank 20. The movement The reciprocating rotation of the motor 18 pivots the axis 3A of the second winding roller 3 around the axis defined by the pivot point 16. In some embodiments, two symmetrical motors 18 can be provided, so that they act on two opposite stringers 4. The ramp 31, or a part thereof, can be fixed between the beams 4, so that said ramp 31 can follow the movement of the second winding roller 3.

The third winding roller 7 is carried by stringers 32 attached to a transverse beam 34 and pivoted at a pivot point 36 with respect to the stationary structure of the rewinding machine 2. Intermediate supports can be integral with the beam transverse 34 to support the third winding roller 7 at intermediate points between the two ends thereof, supported by the stringers 32. The pivoting of the third winding roller 7, ie the translational movement of its axis of rotation 7A to follow the The movement of the winding cores and the coils that are being formed can be conferred by means of a motor 42 by means of a connecting rod-crank system 44, 46 attached to the cross beam 34 in 46A.

A portion 19C of the rolling surface 19 can be attached to the stringers 32, which portion can thus follow the translational movement of the third winding roller 7 during the various stages of the winding cycle.

The operating sequence of the machine 2 of Figure 9 is substantially equal to that described with reference to Figures 1 to 5 and therefore will not be described in detail. Figure 9 shows a completed coil L1, ready to be unloaded from the second winding cradle 10, and a second winding core 2 already inserted in the first winding cradle 6, between the winding rollers 1, 3, 7. The state of operation shown in figure 9 can actually occur in the machine, but this is not indispensable. Depending on the type of regulation, the case may also occur in which the second winding core A2 reaches the position of Figure 9 when the coil L1 has already been ejected from the second winding cradle 10.

The passage of the second winding core A2, with the coil that is being formed around it, through the light 5 defined by the first winding roller 1 and by the second winding roller 3 is allowed or facilitated by moving only the axis 3A of the second winding roller 3, while the axis 1A of the first winding roller 1 remains stationary with respect to The structure of the machine. In this way, the operation of the rewinding machine becomes more uniform, in particular since the path of the winding material upstream of the light 5 is not modified.

An additional advantage of the embodiment of Figure 9 is that the operation of the sectioning element 23 of the web material N is simplified. In fact, it cooperates with a winding roller 1, whose axis of rotation does not move and by both the control of the sectioning stage of the N-band material is simplified.

The use of a first winding roller 1 of larger diameter makes it possible to avoid the need for an intermediate support of the first winding roller 1, simplifying the structure of the machine and improving the quality of the coils.

Claims (19)

1. Automatic continuous peripheral rewinding machine (2) to produce coils (L1) of web material (N) wound around winding cores (A1, A2), comprising: a first winding cradle (6) formed between a first winding roller (1), a second winding roller (3) and a third winding roller (7); the first winding roller (1) and the second winding roller (3) defining a light (5) through which the winding cores (A1, A2) pass with the web material (N) being wound around thereof; a second winding cradle (10) formed between the first winding roller (1), the second winding roller (3) and a fourth winding roller (8); the third winding roller (7) being positioned upstream of the light (5) and the fourth winding roller (8) being placed downstream of the light (5), with respect to the direction of feeding of the winding cores ( A1, A2) through light; characterized by a rolling surface (19) extending around the first winding roller (1) and defining a winding core feed channel (21), between the rolling surface (19) and the first winding roller (1 ); the rolling surface (19) being configured and arranged with respect to the first winding roller (1) such that the winding cores (A1, A2) are fed by rolling in contact with the rolling surface (19) and with the web material (N) dragged around the first winding roller (1). 2. Rewinding machine (2) according to claim 1, comprising a sectioning element (23) of the web material (N) configured and controlled to section the web material (N) at the end of the winding of a coil (L1 ) in the second winding cradle (10); said sectioning element (23) being preferably configured and controlled to cooperate with the first winding roller (1). 3. Rewinding machine (2) according to claim 2, wherein the sectioning element (23) is configured and controlled to press the web material (N) against the first winding roller (1) and to section the material in band (N) generating in the band material a tension greater than the breaking point of the band material; and in which preferably the sectioning element (23) is configured and controlled to section the web material (N) between a new core (A2) inserted in the winding core feed channel (21) and a coil (L1 ) which is forming in the second winding cradle (10) and preferably between the sectioning element (23) and the coil (L1) that is forming in the second winding cradle (10). 4. Rewinding machine (2) according to claim 2 or 3, wherein the sectioning element (23) is configured and controlled to enter the winding core feed channel (21) and cooperates with the first roller of winding (1) at a point downstream of a winding core (A2) inserted into the winding core feed channel (21). 5. Rewinding machine (2) according to one or more of the preceding claims, wherein the rolling surface (19) extends from an inlet of the winding core feed channel (21) to the third winding roller ( 7); preferably a path of the winding cores is provided, which extends beyond the feed channel (21), between the first winding roller (1) and the third winding roller (7), to reach the first cradle of winding (6) 6. Rewinding machine (2) according to one or more of the preceding claims, wherein the winding rollers (1, 3, 7, 8) are arranged and controlled to carry out a first part of the winding of a coil ( L1) in the first winding cradle (6) between the first winding roller (1), the second winding roller (3) and the third winding roller (7) and a last part of the winding of a coil (L1) in the second winding cradle (10), between the first winding roller (1), the second winding roller (3) and the fourth winding roller (8); and in which preferably the third winding roller (7) and the fourth winding roller (8) have moving shafts (7A, 8A) and are controlled to move orthogonally to its axis following the movement of the coil (L1) during the step of increasing coil diameter and transfer from the first winding cradle (6) to the second winding cradle (10). 7. Rewinding machine (2) according to one or more of the preceding claims, wherein at least one of said first winding roller (1) and said second winding roller (3) has a moving shaft (1A, 3A), to control the distance between the first winding roller (1) and the second winding roller (3) and the light dimension (5) between the first winding roller (1) and the second winding roller ( 3). 8. Rewinding machine (2) according to one or more of the preceding claims, wherein the first winding roller (1) has a fixed axis (1A) and the second winding roller (3) has a moving axis (3A ), and in which preferably the first winding roller (1) has a diameter greater than that of the second winding roller (3). 9. Rewinding machine (2) according to one or more of claims 1 to 7, wherein both the first winding roller (1) and the second winding roller (3) have moving shafts (1A, 3A), to move one away from the other and one towards the other preferably symmetrically. 10. Rewinding machine (2) according to one or more of the preceding claims, wherein the movement of the first winding roller (1), the second winding roller (3), the third winding roller (7) and the Fourth winding roller (8) during the winding of the coil (L1) is controlled so that: a first part of the winding of the coil (L1) takes place with the coil in contact with the first winding roller (1), the second winding roller (3) and the third winding roller (7); a second part of the coil winding takes place with the coil in contact with the first winding roller (1), the second winding roller (3), the third winding roller (7) and the fourth winding roller (8 ); A third part of the coil winding (L1) takes place with the coil in contact with the first winding roller (1), the second winding roller (3) and the fourth winding roller (8). 11. Rewinding machine (2) according to one or more of the preceding claims, wherein the tread surface (19) comprises a stationary first part (19A) with respect to a support structure of the rewinding machine (2) , and a part (19B) that moves along with the shaft (7A) of the third winding roller (7). 12. Rewinding machine (2) according to one or more of the preceding claims, comprising a pair of motorized centers (101), configured and arranged to engage with the winding core (A1, A2) for at least a part of a winding cycle, following the motorized centers (101) the feeding movement of the winding core (A1, A2) between the winding rollers (1, 3, 7, 8). 13. Rewinding machine (2) according to one or more of the preceding claims, wherein the first winding roller (1), around which the web material (N) is driven, has a larger diameter, preferably as less than double, than the diameter of the second winding roller (3). 14. Rewinding machine (2) according to one or more of the preceding claims, wherein the first winding roller (1) has an axis (1A) that is stationary with respect to a load bearing structure of the machine rewind (2), and the second winding roller (3) has an axis (3A) that is mobile with respect to the structure of the machine, to allow or facilitate the passage of a coil (L1) that is forming through of the light (5) defined between the first winding roller (1) and the second winding roller (3). 15. Method for winding a web material (N) and sequentially forming coils (L1) of said web material wound around winding cores (A1, A2), comprising the following steps: feeding the web material (N) around a first winding roller (1) of a first winding cradle (6) formed by the first winding roller (1), by a second winding roller (3) and by a third winding roller (7), defining the first winding roller (1) and the second winding roller (3), with a fourth winding roller (8), a second winding cradle (10); inserting a first winding core (A1) into a feed channel (21), formed between the first winding roller (1) and a rolling surface (19) that extends around the first winding roller (1), and feed the winding core (A1) by rolling in contact with the rolling surface (19) and with the web material (N) dragged around the first winding roller (1) and feeding the first winding core (A1) along an insertion path between the first winding roller (1) and the third winding roller (7) and inserting the first winding core (A1) into the first winding cradle (6); carrying out a first part of a winding cycle of a first coil (L1) around the first winding core (A1) in the first winding cradle (6); transfer the first coil (L1) that is forming from the first winding cradle (6) to the inside of the second winding cradle (10) through a light (5) defined between the first winding roller (1) and the second winding roller (3); carrying out a second part of a winding cycle of the first coil (L1) in the second winding cradle (10); at the end of the winding of the first coil (L1) in the second winding cradle (10), insert a second winding core (A2) into the feed channel (21) and along the insertion path between the first roller of winding (1) and the third winding roller (7) and inserting the second winding core (A2) into the first winding cradle (6). 16. A method according to claim 15, comprising the following steps: inserting the second winding core (A2) against the first winding roller (1) by pressing the web material (N) between the second core winding (A2) and the first winding roller (1), and sectioning the web material (N) between the first coil (L1) in the second winding cradle (10) and the second winding core (A2). 17. Method according to claim 15 or 16, comprising the step of acting with a sectioning element (23) on the web material (N) to section the web material thereby generating a rear edge (Lf) of the first coil (L1) and a leading edge (Li) with which to start winding a second coil around the second winding core (A2); and also preferably comprising the step of tightening the web material (N) between the sectioning element (23) and the first roller (1). 18. A method according to claim 17, further comprising the following steps: moving the third winding roller (7) towards the light (5) between the first winding roller (1) and the second winding roller (3) in a coil formation stage; When the bobbin is in contact with the fourth winding roller (8), move the third winding roller (7) away from the light (5) and return the third winding roller to the initial position. 19. A method according to one or more of claims 15 to 17, wherein between the first part of the winding cycle and the second part of the winding cycle, an intermediate part of the winding cycle is carried out, wherein the The bobbin (L1) being wound is in contact with the first winding roller (1), the second winding roller (3), the third winding roller (7) and the fourth winding roller (8) and moving to through the light (5) between the first winding roller (1) and the second winding roller (5).