Patent Application
20160001997
The present invention relates to methods and machines to produce rolls of web material, particularly, although without limitation, paper rolls, especially tissue paper rolls, for instance rolls of toilet paper, kitchen towels or the like.
In the paper industry, particularly in the production of logs of toilet paper, kitchen towels or the like, reels of large dimensions (called parent reels) are formed by winding tissue paper coming directly from the continuous paper-making machine. These reels are then unwound and rewound to produce rolls or logs of smaller diametric dimensions, corresponding to the diametric dimension of the end product intended for consumption. These rolls have an axial length equal to a multiple of the finished roll intended for sale and are therefore cut by means of severing machines to form the end products destined for use, which are then packaged and sold.
For producing logs or rolls of web material, the modern rewinding machines use winding rollers that, combined and arranged in various ways and adequately controlled, allow to automatically produce logs or rolls at high rate by means of continuous feed of the web material. After a roll has been wound, it shall be moved away from the winding area, severing the web material (through cutting or tearing thereof or in another way), thus allowing to start the winding of a subsequent log or roll. Usually, winding is performed around winding cores, typically, although not exclusively, made of cardboard, plastic or other adequate material. In some cases winding is performed around mandrels that can be removed and recycled, i.e. that are removed from the completed roll after it has been completely wound, and are then inserted again into the rewinding machine to wind a new roll.
In the newest rewinding machine the winding motion is imparted to the logs or rolls through contact with two or more rollers rotating at controlled speed. These rewinding machines are called surface rewinding machines, as the winding movement is imparted peripherally through contact between the surface of the winding rollers and the surface of the rolls or logs being formed. Examples of automatic continuous surface rewinding machines of this type are described in the U.S. Pat. No. 5,979,818 and in other patents of the same class, as well as in the reference documents cited in this patent. An improvement to the machine described in this US patent is disclosed in WO-A-2011/104737 and in WO2007/083336. In these known rewinding machines the web material is severed by means of a severing, cutting, or tearing member, which cooperates with a winding roller having a fixed axis, around which the web material is fed and which defines, together with a second winding roller, a nip where the winding cores are inserted.
These machines are also referred to as continuous and automatic machines, as the various steps of the winding cycle of each roll follow one another automatically, that is to say from the production of one roll to the production of the subsequent roll without stopping and supplying the web material at nearly or substantially constant speed. In this description and in the appended claims the term “automatic continuous rewinding machine” will be used to indicate this type of machines.
One of the critical phases in the continuous automatic surface rewinding machines of the type described above is the so-called exchange phase, i.e. the step where operations are performed to sever the web material, unload the finished log, and start winding a new log around a new winding core inserted in the winding nip.
Different solutions have been studied to perform these operations automatically, quickly and effectively, for instance using winding rollers rotating at controlled speed that accelerate and/or decelerate in a synchronized manner to facilitate the correct movement of the finished rolls and of the new cores. In some cases tearing systems have been provided, wherein the web material is severed by means of speed difference. In other cases pressurized air systems, suction systems, mechanical systems or the like have been provided to sever the web material.
WO-A-2012/042549 discloses an automatic surface rewinding machine with four rollers. The use of four rollers, all of which, or at least some of which have movable axes, allows to define two winding cradles and to control the roll being formed more effectively. In some embodiments described in that document, the roll being formed is always in contact with at least three winding rollers and, in some cases, it can be temporarily in contact with four winding rollers. This allows controlling the winding cycle, the shape of the roll and the winding density in a particularly efficient way. In some embodiments the web material is severed by lengthening the path thereof between two winding rollers. This results in the web material being severed to form a free tail edge of a completed roll and a free leading edge of the subsequent roll to start winding this latter on a new core. This machine allows achieving appreciable results in terms of winding accuracy and operation reliability; however, it has some aspects that can be improved. Particularly, in some cases the correct operation and the reproducibility of the winding cycle may depend upon the features of the processed material, i.e. of the web material and/or the winding cores.
According to what described above, an automatic continuous surface rewinding machine with four rollers is provided, wherein rolls of web material are wound around winding cores at very fast frequency, without stopping supplying the web material, i.e. feeding the web material continuously or substantially continuously towards a winding head, comprising, in addition to the winding rollers, a mechanism for severing the web material at the end of every winding cycle.
“Continuously or essentially continuously feed” means that the feed speed of the web material is substantially independent of the winding cycle, being understood that other factors can change, also considerably, the feed speed of the web material. For instance, to replace a parent reel from which the web material is supplied, or in the case the web material breaks, it could be necessary to slow down or even to stop the feed of the web material towards the winding head. However, this speed change or stop is not linked to the winding cycle of the single rolls.
Advantageously, the winding head of the rewinding machine may comprise a first winding roller, a second winding roller and a third winding roller, defining a first winding cradle. A fourth winding roller forms, together with the first winding roller and the second winding roller, a second winding cradle. The first winding roller and the second winding roller define a nip through which the winding cores pass, with the roll being formed around them, moving from the first to the second winding cradle.
Advantageously, both the third and fourth winding roller have a movable axis to follow the motion of the winding core and of the roll in the first winding cradle, in the second winding cradle and in the nip between these cradles.
Suitably, a severing member for the web material cooperates with the third winding roller, i.e. the first roller the web material meets when entering the winding area or winding head.
The severing member may be designed and controlled so as to pinch the web material between the severing member and the third winding roller. The third winding roller may have a surface with a low friction coefficient in the area where the severing member presses, for instance annular bands with low friction coefficient. When the web material is pinched against the third winding roller by the pressing members of the severing member, or other similar members with which the severing member is provided, it slides on this roller and remains substantially stationary, held by the severing member. This results in the web material being tensioned downstream of the severing member, causing tearing thereof. In case of perforated web material, tearing occurs at a perforation line.
The pinching movement may be completely performed by the severing member only. In some embodiments the pinching movement may be performed by the third winding roller, or partly by the third winding roller and partly by the severing member. In general, the movement is referred to the fixed structure of the machine.
In other embodiments, the severing member may comprise a linear element extending transversally with respect to the feed path for the web material and therefore substantially parallel to the axes of the winding rollers. The linear element of the severing member may be provided with a continuous or alternating severing movement, causing the passage of said linear element through the web material feed path, so that the web material is severed by means of the linear element. In this case, the severing member cooperates advantageously with the third winding roller, acting onto the web material in a portion thereof comprised between the third winding roller and the roll being formed in the second winding cradle. The path of the linear element may extend between the first winding roller and the third winding roller.
In practical embodiments, the movement of the linear element is substantially orthogonal to the longitudinal development of said linear element. For instance, the linear element may be provided with a movement along a circular trajectory. In advantageous embodiments the linear element may be supported by arms pivoting around an axis of rotation. In other embodiments the movement of the linear element may be a translation movement.
The linear element may comprise a wire. To efficiently sever the web material, the linear element may be tensioned. To this end one or more tensioning members may be provided, such as a hydraulic jack or the like.
In advantageous embodiments, the linear element may be a wire, a cable, a stranded wire or any other element whose cross section is such to reduce bending deformations resulting from dynamic stresses during motion. In some embodiments the linear element has a nearly circular cross section.
The linear element may be made of materials with high tensile strength, for instance fibers of Kevlar, i.e. aramid fibers.
The linear element may be provided with reciprocating motion, controlled so as to move alternatively from one to the other of two rest positions that can define the end positions of the trajectory along which the linear element moves. These two positions are adequately arranged on opposite sides of the path of the web material. In this way the operation of the linear element is reciprocating, i.e. in a working cycle, that is when a first winding ends, the linear element acts onto the web material severing it through a movement from the first to the second position, crossing the path of the web material in one direction. When a second, i.e. a subsequent winding cycle ends, the linear elements performs a second working cycle moving contrarily than in the previous working cycle, i.e. crossing the path of the web material in opposite direction, moving from the second to the first position.
In other embodiments the linear element may have a rotary motion in a single direction, discontinuous and synchronized with the roll formation. The linear element may be carried for instance by arms pivoted around the axis of the first winding roller.
In general, both the third winding roller and the severing member are movable. The third winding roller (or more specifically the axis of rotation thereof) is movable to follow the forward movement of the roll in the first winding step towards the nip between the first and the second roller and to come back into the start position for receiving a new core. In some embodiments the severing member is movable to take a position where it cooperates with the third winding roller and a position where it allows the passage of the new core when the winding starts. These two movements are suitably coordinated with each other, so that the third winding roller is positioned correctly and in phase with the movement of insertion of a new winding core. The third roller is positioned so as to allow the winding core to be correctly inserted and controlled and to allow the cooperation between the roller and the severing member. While in the known rewinding machines provided with a severing member this latter usually cooperates with a winding roller having a fixed axis, according to some embodiments of the rewinding machine described herein the severing member cooperates with a winding roller having a movable axis, that performs a relatively wide movement for accompanying or following the new core and the roll when the winding starts and a subsequent movement back towards the start position for inserting the new winding core.
According to an embodiment, a continuous automatic surface rewinding machine is therefore provided, for producing rolls 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, and a second winding cradle, formed between the first winding roller, the second winding roller and a fourth winding roller; wherein the first winding roller and the second winding roller define a nip; through said nip the winding cores, around which the web material is wound, pass and the web material is fed towards a roll being formed in the second winding cradle. The winding rollers are arranged and controlled to perform a first part of the winding of a roll between the first winding roller, the second winding roller and the third winding roller, and a final part of the winding of a roll between the first winding roller, the second winding roller and the fourth winding roller, the fourth winding roller being arranged downstream of the nip and the third winding roller being arranged upstream of the nip, with respect to the feed direction of the winding cores. The third winding roller and the fourth winding roller have movable axes and are controlled so as to translate orthogonally to their axis, following the movement of the roll during growing thereof and transferring from the first winding cradle to the second winding cradle. The machine further comprises a severing member cooperating with the third winding roller and acting on the web material between a winding core and the nip, to sever the web material thus generating a tail edge of a completed roll and a leading edge of a new roll to be wound. In some embodiments the severing member comprises advantageously pressing members pushing against the third winding roller. In other embodiments the severing member comprises a linear or wire-shaped element moving transversally to the (feed path of the) web material, to sever it after it has been completely wound.
In practical embodiments the machine comprises a curved rolling surface extending around the third winding roller and ending at the second winding roller forming an area for the passage of the winding cores and of the rolls from the rolling surface to the second winding roller; wherein between the curved rolling surface and the third winding roller a feeding channel is defined for feeding the winding cores.
According to a different aspect, a method is provided to wind a web material and produce in sequence rolls of said web material wound around winding cores, comprising the steps of: arranging 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, said second winding roller and a fourth winding roller; performing a first part of a winding cycle of each roll in the first winding cradle, and a subsequent part of the winding cycle of each roll in the second winding cradle, the roll being wound moving from the first winding cradle to the second winding cradle through a nip defined between the first winding cradle and the second winding cradle. When a roll has been completely wound, the web material is severed by means of a severing member cooperating with the third winding roller. In some embodiments the web material is severed by pinching it against the third winding roller. In other embodiments the web material is severed by means of a movable cutting or severing linear element that intersects the feed path of the web material, downwards of the third winding roller. The linear element severs the web material crossing the feed path thereof between the third winding roller and the roll being completed in the second winding cradle.
As the third winding roller is movable and controlled to move during the winding cycle of each roll, the machine and the method of the invention provide advantageously for synchronizing the movement of the axis of the third winding roller and the movement of the severing member.
In some embodiments the machine comprises a curved rolling surface extending around the third winding roller and ending at the second winding roller forming an area for the transfer of the winding cores and of the rolls from the rolling surface to the second winding roller. Between the curved rolling surface and the third winding roller a feeding channel is defined for feeding the winding cores. When the severing member comprises a linear element, this latter may enter a seat provided in the curved rolling surface. In some embodiments the curved rolling surface may be defined by the edges of a plurality of laminar elements adjacent to one another and aligned nearly parallel to the axes of the winding rollers. In this case, each laminar element may have a groove or notch inside which the linear element can penetrate. The grooves or notches of the single laminar elements are advantageously aligned with one another to form an elongated seat, inside which the linear element enters when moving towards the side of the path of the web material, on which the rolling surface is located.
Further features and embodiments of the invention will be described in greater detail below with reference to the accompanying drawings and are defined in the attached claims, which form an integral part of the present description.
The invention will be easier to understand by means of the description below and the attached drawing, which shows non-restrictive practical embodiments of the invention. More in particular, in the drawing:
Summarizing, in the illustrated embodiment the machine, indicated as a whole with number 2, comprises a first winding roller 1 with rotation axis 1A, arranged at the side of a second winding roller 3 having rotation axis 3A. The axes 1A and 3A are parallel to each other. Between the two winding rollers 1 and 3 a nip 5 is defined, through which a web material N is fed (at least during part of the winding cycle of each roll) to be wound around winding cores A1, A2, around which logs or rolls L1 form.
As it will be better explained below, also the winding cores pass through the winding nip 5. The winding cores A1, A2 are inserted in the machine upstream of the nip 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. 7A indicates the rotation axis of the third winding roller 7, parallel to the axes 1A and 3A of respectively the first winding roller 1 and the second winding roller 3.
The winding cores terminate receiving the web material N wound around them when they are in a second winding cradle 10 arranged downstream of the nip 5. 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. The rotation axis of the fourth winding roller 8 is indicated with 8A. Number 12 indicates a pair of arms hinged at 12A and supporting the fourth winding roller 8. The arrow f12 indicates the oscillation movement, i.e. the movement of reciprocating rotation of the arm 12, and consequently of the fourth winding roller 8. In other embodiments the fourth winding roller 8 may be carried by a system comprised of slides movable on linear guides, instead of arms pivoted around an axis of oscillation or reciprocating rotation.
If not otherwise specified, in the description and in the appended claims the terms “upstream” and “downstream” refer to the feed direction of the web material and of the axis of the winding core.
The third winding roller 7 is provided with a movement towards and away from the winding nip 5. To this end, in some embodiments the third winding roller 7 is supported by a pair of arms 9 pivoted around an axis 9A to oscillate, i.e. to rotate in a reciprocating manner according to the double arrow f9. In other embodiments, not shown, the third winding roller 7 may be supported by slides movable on linear guides, so as to follow a rectilinear trajectory.
The path of the web material N extends around the third winding roller 7 and around the first winding roller 1, forming, during some steps of the winding cycle (see for instance
Upstream of the winding nip 5, of the first winding roller 1 and of the second winding roller 3 a core feeder 11 is arranged, that can be designed in any suitable manner.
The winding cores may come from a so-called core-winder, i.e. a machine for forming the winding cores associated with the converting line for the web material N, wherein the rewinding machine 2 is arrangetd.
In this case, the core feeder 11 comprises a rotating equipment 14 carrying gripping member 15 engaging the winding cores and transferring them towards a feeding channel, described below.
In some embodiments the rewinding machine comprises a rolling surface 19 for the winding cores. The rolling surface 19 may have an approximately cylindrical shape, generally coaxial with the third winding roller 7 having a movable axis, when this roller is in the position of
The rolling surface 19 and the cylindrical surface of the third winding roller 7 form a feeding channel 21 for the winding cores A1, A2. When the third winding roller 7 is in the position of
In some embodiments the rolling surface 19 is formed by a comb-shaped structure, with a plurality of arched plates adjacent to one another, between which there are free spaces. A severing member, indicated as a whole with number 23, for the web material N can be inserted through said free spaces between adjacent plates forming the rolling surface 19. The severing member 23 may be a presser, comprising a plurality of pressing members 24. The severing member 23 is movable in reciprocating rotary motion around an axis 23A approximately parallel to the axes of the winding rollers. f23 indicates the movement of the severing member 23. Each single pressing member may have a pressure pad 24A. The pressure pad 24A may be made for instance of an elastically yielding material with high friction coefficient, for instance rubber.
As it will be better illustrated below with reference to an operating cycle, synchronized with the movement of the other members of the machine, the severing member 23 is pressed against the third winding roller 7 to pinch the web material N between the pressers 24 and the surface of the third winding roller 7. This latter may have a surface with annular bands with high friction coefficient and annular bands with low friction coefficient. In this context, the term “high” and “low” indicate a relative value of the friction coefficients of the two series of annular bands alternated the ones with the others. The bands with low friction coefficient are in correspondence of areas where the pressing members 24 push. In this way, when the web material N is pinched against the third winding roller 7 by means of the pressing members 24, it tends to be stopped by the pads 24A and to slide on the annular bands with low friction coefficient of the third winding roller 7.
Preferably, the feed speed of the web material N is substantially constant. Substantially constant speed means a speed varying slowly with respect to the winding speed and because of factors that are independent of the operations performed by the members of the winding head described above, that are controlled so as to perform the winding cycle, to unload the completed roll, to insert a new core and to start the winding of a new roll at constant feed speed of the web material towards the groups of winding roller and in particular towards the third winding roller 7.
While the roll L1 is being wound, outside of the so-called exchange phase, i.e. a transitory phase in the operation of the machine, the peripheral speeds of the winding rollers 1, 3, 7, and 8 are substantially equal and all the various winding rollers rotate in the same direction, as indicated by the arrows in the drawing. “Substantially equal” means in this case that the speed can vary only according to the needs for controlling the compactness of the winding and the tension of the web material N between the winding roller 7 and the winding roller 8, for instance to balance the change in tension that could be caused by the displacement of the center of the roll being formed along the path between the winding rollers. In some embodiments this difference in the peripheral speeds of the rollers may be typically comprised between 0.1 and 1% and preferably between 0.15 and 0,5%, for instance between 0.2 and 0.3%, being understood that these values are given just by way of non limiting example. Furthermore, the peripheral speeds may vary slightly to cause the forward movement of the roll being formed, as explained below, so that it passes from the first winding cradle 6 to the second winding cradle 10.
The roll forming cycle will be described below with reference to
In
C indicates a continuous line of glue, or a series of spots of glue, applied on the outer surface of the second winding core A2.
The second winding core A2 in pushed by the core feeder 11 inside the feeding channel 21 defined between the third winding roller 7 and the rolling surface 19.
In this step of the winding cycle the third winding roller 7 is positioned so as to be approximately coaxial with the generally cylindrical rolling surface 19. The distance between the portion 19B of the rolling surface 19 and the cylindrical surface of the third winding roller 7 is slightly lower than the diameter of the winding core A2. In this way the winding core A2 is pushed while entering the feeding channel 21, thus generating a friction force between the surface of the same winding core A2 and the rolling surface 19, as well as between the surface of the winding core A2 and the web material N driven around the cylindrical surface of the third winding roller 7. Thus, due to the rotation of the third winding roller 7 and the forward movement of the web material N, the winding core A2 accelerates angularly, starting to roll on the rolling surface 19. Along the second portion 19C of the rolling surface 19, the radial dimension of the feeding channel 21 increases, reducing the diameter deformation of the winding core A2 and allowing starting winding of the web material N around it, with consequent formation of turns of a new roll.
During the rolling movement, the line of glue C applied on the winding core A2 comes into contact with the web material N, causing the adhesion thereof on the winding core.
In this step of the winding cycle also the breakage or severing of the web material by means of the severing member 23 takes place. This latter is made oscillate against the third winding roller 7, so as to pinch, by means of the pads 24A, the web material N against the surface of the third winding roller 7. As the winding rollers 1, 3, and 8 continue to rotate, winding the web material N on the roll L1, the web material is tensioned between said roll L1 and the point where the web material N is pinched against the third winding roller 7 by means of the severing member 23. The tension exceeds the breaking point, for instance in correspondence of a perforation line, thus generating a tail edge Lf, that will finish to be wound on the roll L1, and a leading edge Li, that will be wound on the new winding core A2.
To allow the winding core A2 to move forward along the feeding channel 21, the severing member 23 has been made rotate around the axis 23A up to exit from the feeding channel 21. Thanks to the glue C, the web material N adhered on the winding core A2 and begins therefore to be wound on the winding core A2 thus starting the winding of a second roll L2 while the core moves forward rolling along the channel 21.
The first roll L1 starts the ejection movement from the second winding cradle 10, for instance by acting on the peripheral speeds of the rollers 1, 3, and 8. In some embodiments the roller 8 may be accelerated angularly and/or the roller 3 may be slowed angularly to cause the movement of the roll L1 away from the second winding cradle 10 towards an unloading slide 31. The fourth winding roller 8 oscillates upwards to allow the passage of the roll L1 towards the unloading slide 31.
In
The completed roll L1 is unloaded onto the slide 31.
The formation of the second roll L2 continues, feeding the web material N around the new winding core A2, with the diameter of the new roll L2 that consequently increases. The third winding roller 7 can move thanks to the movement of the arms 9 around the pivot or axis 9A, following the diameter increase of the second roll L2.
Once a part of the winding cycle has been performed in the winding cradle 6, the roll L2 is transferred in the second winding cradle 10, where the winding is completed. To this end it is necessary for the roll L2 to pass through the nip 5. To this end, in some embodiments one or preferably both the winding rollers 1 and 3 are supported by respective arms 1B, 3B oscillating around oscillation axes 1C, 3C.
As it is shown in
The forward movement of the axis of the roll L2 may be suitably obtained by controlling the movement of the winding rollers, which, moving the reciprocal position of their axes, make the roll move forward in and through the area of minimum distance between the rollers 1 and 3. For instance, the forward movement may be obtained pushing the roll by means of the third winding roller 7. In some embodiments it is possible to facilitate, support or affect the movement of the roll by temporarily changing the peripheral speeds of the rollers, for instance by reducing for a short time the peripheral speed of the second winding roller 3.
While in the embodiment of
The time the second winding core A2 remains in the position of
When the roll L2 is in the second winding cradle 10, the winding of the second roll L2 continues up to achieve the condition shown in
The conformation of the members of the rewinding machine is such that the path followed by the center of the winding cores A1, A2 from the time they come into contact with the two rollers 1, 3 up to the time the roll starts to be unloaded between the rollers 3 and 8 losing the contact with the roller 1, is substantially rectilinear. This allows a more regular winding and facilitates the use of centers that can be inserted in the opposite ends of the winding cores to improve control over the rotary and forward movement of the core and the roll during the winding cycle, combining the surface winding technique and an axial or central winding, as described for instance in U.S. Pat. No. 7,775,476 and in US-A-2007/0176039.
In this embodiment the machine, indicated as a whole with reference number 2, comprises a first winding roller 1 with a rotation axis 1A, arranged at the side of a second winding roller 3 having a rotation axis 3A. The axes 1A and 3A are substantially parallel to each other. Between the two winding rollers 1 and 3 a nip 5 is defined, through which a web material N is fed to be wound around winding cores A1, A2, around which logs or rolls L1, L2 are formed. Through the winding nip 5 pass also the winding cores A1, A2 that are inserted into the machine upstream of the nip 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, rotating around an axis indicated again with 7A.
The winding cores end receiving the web material N wound around them when they are in a second winding cradle 10 arranged downstream of the nip 5 formed by the first winding roller 1, the second winding roller 3 and a fourth winding roller 8. The rotation axis of the fourth winding roller 8 is indicated with 8A. Reference number 12 indicates a pair of arms hinged at 12A and supporting the fourth winding roller 8. The arrow f12 indicates the pivoting movement, i.e. the movement of reciprocating rotation of the arm 12, and consequently of the fourth winding roller 8.
The third winding roller 7 is provided with a movement towards and away from the winding nip 5. In some embodiments the third winding roller 7 is supported by a pair of arms 9 pivoted around an axis 9A to rotate in a reciprocating manner according to the double arrow f9.
The path of the web material N extends around the third winding roller 7 and around the first winding roller 1, forming, during some steps of the winding cycle (see for instance
Upstream of the winding nip 5, of the first winding roller 1 and of the second winding roller 3 a core feeder 11 is arranged, that can be designed in any adequate manner.
In some embodiments the rewinding machine comprises a rolling surface 19 for the winding cores. The rolling surface 19 may have an approximately cylindrical shape, approximately coaxial with the third winding roller 7, when this roller is in the position of
The rolling surface 19 and the cylindrical surface of the third winding roller 7 form a feeding channel 21 for the winding cores A1, A2. When the third winding roller 7 is in the position of
The rewinding machine 2 comprises a severing member cooperating with the third winding roller 7 and more exactly arranged and controlled to interact with the web material that is in the portion comprised between the third winding roller 7 and the roll being formed, as it will be better described in greater detail with reference to the sequence of
In this embodiment again, the severing member is indicated as a whole with number 23. It comprises a linear element 53, for instance a suitably tensioned wire or a cable, or a substantially rigid linear element, arranged according to a line as similar as possible to a straight line, preferably nearly parallel to the axes of the winding rollers 1, 3, 7, and 8 and that has a limited tendency to bending deformation under the effect of the dynamic stresses due to its working movement, described below.
The linear element 53 is provided with a motion according to an actuating trajectory orthogonal to the longitudinal extension of said linear element and intersecting the path of the web material, in an area comprised between the winding rollers 1 and 7 or more in general between the winding roller 7 and the roll in the final phase of the winding cycle.
In some embodiments, the linear element 53 is carried by a pair of arms 51 pivoting around a pivoting axis 51A, so as to move the linear element 53 according to the double arrow f53, in the way and for the purposes described in greater detail below.
The severing member 23 can move along a trajectory extending between two end or rest positions, one of which is shown in
At least while the roll L1 is being wound, outside of the so-called exchange phase, which is a transitory phase in the operation of the machine, the peripheral speeds of the winding rollers 1, 3, 7, and 8 are substantially equal to one another and all the various winding rollers rotate in the same direction, as indicated by th arrows in the drawing. “Substantially equal” means in this case that the speeds may vary only according to the needs for controlling the compactness of the winding and the tension of the web material N between the winding roller 7 and the winding roller 8, for instance to balance the change in tension that could be caused by the displacement of the center of the roll being formed along the path between the winding rollers, as well known. Furthermore, the peripheral speeds may vary slightly to cause or facilitate the forward movement of the roll being formed, as explained below, so as to facilitate the passage thereof from the first winding cradle 6 to the second winding cradle 10. Changes in speed may be useful to facilitate or cause the passage of the roll through the nip 5 and to unload the roll from the second winding cradle, as known to those skilled in the art.
The sequence of
In
In
A line of glue C applied onto the outer surface of the tubular core A2 comes into contact with the web material in the portion entrained around the third winding roller 7, due to the effect of the start of the rolling movement of the tubular core A2 on the rolling surface 19.
In
In
In this phase of the winding cycle the third winding roller 7 moves due to the effect of the rotation of the arms 9 around the pivot 9A (arrow f9) to follow the movement of the roll L2 during the passage through the nip 5. In this way the second roll L2 is wound in contact with three winding rollers 1, 3, 7.
After the first roll L1 has been ejected from the second winding cradle, the fourth winding roller 8 has been lowered (arrow f8) to take contact with the second roll L2 while this moves through the nip 5 or when it has passed the nip 5 to enter the second winding cradle between the rollers 1, 3, and 8. In the phase illustrated in
The forward movement of the new roll L2 through the nip 5 between the first winding roller 1 and the third winding roller 3 may be provided by changing the peripheral speeds, for instance by slowing the second winding roller 3, or may be facilitated by this change in speed, in combination with the mutual movement of the rollers 1, 3,7.
Once the roll L2 has passed through the nip 5, the winding members take the position of
In
In
The linear element 53 continues its movement passing through the nip formed by the first winding roller 1 and the third winding roller 7, up to the final rest position (
In
In the subsequent
From
In the embodiment illustrated in
Furthermore, as it is clearly apparent by comparing the sequence of
It is understood that the drawing only shows an example provided by way of a practical arrangement of the invention, which can vary in forms and arrangement without however departing from the scope of the concept underlying the invention. Any reference numerals in the appended claims are provided to facilitate reading of the claims with reference to the description and to the drawing, and do not limit the scope of protection represented by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| FI2013A000046 | Mar 2013 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2013/061289 | 12/23/2013 | WO | 00 |
