METHOD AND APPARATUS FOR AUTOMATICALLY JOINING REELS OF WEB MATERIAL Technical field

[01] The present invention relates to a method for automatically joining reels of web material as well as to an apparatus implementing said method, particularly intended for use in apparatuses capable of automatically replacing said reels of web material.

Prior art

[02] Use of automatic machines that use reels of web material for manufacturing or packaging the products is currently known in various technical sectors. The operation of these automatic machines implies the replacement of the reels being used, at the time when the web material has been completely consumed.

[03] Therefore, apparatuses have been developed that are adapted to automatically replace the reels of web material, without interrupting the normal operating cycle of the machine. These apparatuses essentially join the trailing edge of the expiring reel with the leading edge of a new reel. The operator in charge must therefore periodically supply the apparatus with one or more new reels of web material; the apparatus then automatically replaces the running reel when it is completely expired.

[04] Apparatuses for automatically replacing reels of web material are known for example from patents EP 0 619 231 and EP 2 233 399.

[05] Depending on the type of production, this operation can be requested with relative frequency. In particular, in certain production sectors, such as the construction of electrical energy storage devices, a single reel of web material can be consumed in a few minutes and therefore the replacement of the reel must be repeated with high frequency.

[06] A need that arises in specific production sectors is therefore to speed up the automatic operation of joining the trailing edge of the expiring reel with the leading edge of the new reel, without damaging, during this operation, the web material, which is sometimes very thin.

[07] In fact, there are production sectors, such as the manufacture of electrical energy storage devices, in which the tapes of web material have at least a series of external ends or flags at one side, which can easily be bent or damaged in contact with a surface. This would obviously cause, during the production phase, an inadmissible amount of waste.

[08] Ultimately, the development of increasingly high-performance automatic machines, capable of reaching very high production speeds, makes it urgent to replace the reels of web material equally quickly. This requires in particular that the joining of the trailing edge of the expiring reel with the leading edge of a new reel is carried out automatically at high speed, so that the feeding of the web material to the machine is continuous.

Disclosure [09] The object of the present invention is to solve the abovementioned problems, by devising a method that allows the optimal automatic joining of the reels of web material in the apparatuses for replacing said reels of web material intended to be associated with machines that use this web material for the manufacture or packaging of products.

[10] It is a further object of the invention to provide a method for automatically joining reels of web material that ensures the achievement of a high production speed.

[11] Another object of the invention is to provide a method for automatically joining reels of web material capable of preserving the integrity of such web material.

[12] Still further object of the invention is to provide an apparatus capable of implementing the subject method for automatically joining reels of web material, which is of simple constructive and functional design, equipped with reliable operation, versatile use, as well as relatively economical cost.

[13] The cited objects are achieved, according to the present invention, by the method and the apparatus for automatically joining reels of web material according to claims 1 and 2.

[14] The apparatus for automatically joining reels of web material comprises a joining assembly adapted to take the trailing edge of a first expiring reel of web material and to apply it on the leading edge of a second reel of web material.

[15] According to one aspect of the invention, said leading edge of the second reel of web material is held close to said second reel of web material by a gripping means rotated, at the same angular speed, by the same second reel.

[16] Suitably said leading edge of the second reel of web material bears, on the side facing outwardly, a label of adhesive material.

[17] Preferably said gripping means comprises a radial arm provided at a free end with a support member adapted to be connected to drawing means for putting its surface facing outwardly under vacuum, said radial arm being mounted in axis to said reel and rotated therefrom at the same angular speed.

[18] Preferably said support member comprises a vane developed on a plane tangent to the outer surface of said reel of web material.

[19] Preferably said gripping means is operable in radial direction to said reel of web material to facilitate the application of said leading edge of the second reel of web material on said trailing edge of the first expiring reel of web material.

[20] Preferably said joining assembly comprises a plurality of rollers rotatable, in a suitable phase relationship, according to respective rotation axes parallel to the rotation axis of said reels, in order to sequentially grip said web material being unwound from said first reel, cutting said trailing edge of the same first reel, transferring said trailing edge of the first reel onto said leading edge of the second reel and joining said trailing edge using said label of adhesive material to said leading edge. [21] Suitably said rollers are counter-rotating with respect to each other.

[22] Preferably said joining assembly comprises a first roller for taking up and unwinding the web material, said first roller being connectable to drawing means for putting its peripheral surface under vacuum, so as to retain said web material being unwound from the first reel.

[23] Preferably, said joining assembly comprises, downstream of said first roller, according to the direction of advance of said web material, a second transfer roller of said trailing edge of the first reel on said leading edge of the second reel, means for cutting the web material being unwound from said first reel, adapted to define said trailing edge, being carried on said second roller.

[24] Preferably said cutting means comprises a blade housed inside a seat made radially in the body of said second roller, said blade being adapted to be actuated between an inactive retracted position and an advanced position, protruding from said second roller to perform the cutting of the web material.

[25] Preferably, said joining assembly comprises, downstream of said second roller, a third drive roller of the web material to be fed, following the joining of said leading edge of the second reel to said trailing edge of the first reel, said third roller being connectable to drawing means for putting its peripheral surface under vacuum.

[26] Suitably, said first reel and said second reel of web material are arranged in respective working positions arranged side by side and coplanar, supported in rotation according to parallel axes by respective motorized coupling members.

[27] Conveniently, said joining assembly is carried by a movable assembly adapted to translate the same joining assembly in an axial direction to said rollers for a stroke whose amplitude is greater than the thickness of the web material.

[28] Preferably said movable assembly is movable between a working position, which is coplanar with said first and second reels of web material and a retracted position, in which said joining assembly does not engage said web material unwinding from said reels.

[29] Preferably, said movable assembly is capable of angularly rotating said junction assembly between a first and a second working positions, which are specular to each other.

[30] The present invention also concerns a method for automatically joining reels of web material, comprising the steps of a. arranging in a working position, placed side by side to the working position of a first unwinding reel of web material to feed in line the same web material, a second reel of web material, said first and said second reel being rotatable with parallel axes of rotation; b. associating a leading edge of said second reel of web material with gripping means, caused to rotate by the same second reel (22) of web material, said leading edge carrying adhesive means (4) on the side facing outwardly; c. detecting by sensor means the residual diameter of said first unwinding reel of web material; d. rotating said second reel of web material, when detecting a predetermined residual diameter of said first unwinding reel of web material; e. cutting a trailing end of said first unwinding reel of web material; f. engaging said trailing end of said first reel of web material with a joining assembly arranged downstream of said first reel according to the feed direction of said web material; g. applying said trailing end of said first reel of web material on said leading edge of said second reel of web material rotated by said gripping means integrally with the same second reel of web material; h. joining said trailing end and said leading edge of the reels of web material by means of said adhesive means associated with the same leading edge of said second reel.

[31] The subject method provides for rotating the second reel of web material with a peripheral speed substantially corresponding to the feeding speed of said web material to the machine that uses it.

[32] According to an aspect of the invention, the method provides for engaging said trailing edge of the first reel of web material with a plurality of rollers of said joining assembly, said rollers being rotatable, in an appropriate phase relationship, according to respective axes of rotation, which are parallel to the axis of rotation of said reels, to carry out in sequence the gripping of the said web material unwinding from said first reel, the cutting of said trailing edge of the same first reel, the transfer of the said trailing edge of the first reel on said leading edge of the second reel and the joining, by means of said label of adhesive material, of said trailing edge to said leading edge.

[33] According to a further aspect of the invention, the method involves translating said joining assembly, at the end of the joining step of said trailing and leading edges of said reels, from a working position, coplanar to said first and second reel of web material, to a retracted position, in which said rollers of the joining assembly do not engage said web material unwinding from said reels.

[34] Conveniently, in said retracted position of the joining assembly, the method provides for rotating the joining assembly angularly between a first and a second working position specular to each other, so as to prepare said rollers for the subsequent joining operation.

Description of drawings

[35] The details of the invention will be more evident from the detailed description of a preferred embodiment of the apparatus for automatically joining reels of web material, illustrated by way of example in the attached drawings, in which

Figure 1 is a side view of the apparatus for automatically joining reels of web material according to the present invention;

Figure 2 is an enlarged portion of the apparatus shown in Figure 1 ; Figures 3 and 4 are respectively a side view and a front view of a part of the apparatus; Figures 5 to 12 show a schematic side view of the apparatus in subsequent operating steps.

Description of embodiments of the invention

[36] With particular reference to these figures, the apparatus for automatically joining reels of web material is indicated in whole with the reference number 1. In particular, in the figures, numbers 21 and 22 respectively refer to a first unwinding reel of web material 2, to feed said web material 2 to an automatic machine that uses it for production purposes, and a second reel of web material 2 to be replaced by the first reel when the latter has expired. Hereafter, for simplicity, the reels 21 , 22 are also referred to as the running reel and the new reel.

[37] Within the scope of the present invention, automatic joining of the reels of web material means the joining of the trailing edge of the expiring reel with the leading edge of a new reel, so as to make the feeding of the web material to the machine continuous.

[38] The reels 21 , 22 of web material are adapted to be supported by a frame of the apparatus, in a way known in the art and not shown in the drawings, in a substantially coplanar working position and with the respective axes of rotation that are parallel. Preferably said axes of rotation are horizontal.

[39] Obviously, pairs of reels of web materials of different types can be arranged on the frame of the apparatus, to be fed simultaneously into the machine.

[40] The reels 21 , 22 of web material are adapted to be inserted in a known manner on respective coupling members, operated in rotation by special driving members. Said coupling members consist essentially of a cylindrical hub 10 on which the tube or spindle 23 of the reel of web material is adapted to engage.

[41] According to the present invention, a gripping member 3 of the leading edge of the same web material is associated with each reel of web material. In a preferred embodiment, said gripping member 3 consists of a radial arm 30 provided at a free end with a vane 31 adapted to be connected to drawing means for putting its surface facing outwardly the reel under vacuum (see Figures 3 and 4). The radial arm 30 is mounted in axis to the reel and rotated thereby, at the same angular speed.

[42] The vacuum vane 31 is adapted to retain the aforementioned leading edge of the web material, bearing a label 4 of adhesive material on the side facing outwardly the reel.

[43] Conveniently, the gripping member 3 is adapted to be driven in a radial direction to the reel of web material, as specified below, to facilitate the application of the leading edge of the second reel of web material on the trailing edge of the first expiring reel of web material.

[44] The apparatus 1 includes a joining assembly 5 suitable for taking the trailing edge of the first running reel 21 when it is about to expire and applying it to the leading edge of the second reel 22, carried by the vane 31 of the gripping member 3 and bearing the label 4 of adhesive material (see Figure 2). The joining assembly 5 includes a plurality of rollers rotatable, in a suitable phase relationship, according to respective rotation axes parallel to the rotation axis of the reels 21 , 22. It is possible to provide that said rollers have a rubberized external surface for a better grip on the web material.

[45] Conveniently, the rollers of the joining assembly 5 are arranged coplanar and counterrotating with respect to each other.

[46] In particular, the joining assembly 5 includes a first roller 51 for unwinding the web material 2, which is connectable to drawing means to put its peripheral surface under vacuum, in operation, so as to retain the web material 2 unwinding from the first reel 21 .

[47] Downstream of the first unwinding roller 51 , according to the direction of advance of the web material 2, a second roller 52 is arranged to transfer the trailing edge of the first reel 21 onto the leading edge of the second reel 22. Means 6 for cutting the web material 2 unwinding from the first reel 21 , suitable for defining said trailing edge, is carried on the second transfer roller 52. In a preferred embodiment, the cutting means 6 consists of a blade 60 housed inside a seat 61 made radially in the body of the second roller 52. The blade 60 is operable between an inactive retracted position and an advanced position, protruding from the second roller 52 to cut the web material 2.

[48] Downstream of the second conveying roller 52, a third roller 53 is arranged to drive the web material 2 to be fed to the machine, after joining the leading edge of the second reel 22 to the trailing edge of the first reel 21. The third drive roller 53 is connectable to drawing means to put its peripheral surface under vacuum, in operation.

[49] As better specified below, the joining assembly 5 is carried by a movable assembly, not shown in the drawings, adapted to arrange the positioning of the rollers 51 , 52, 53 according to the arrangement of the reel of web material being unwound. In particular, this movable assembly is adapted to translate the joining assembly 5 in the axial direction of the rollers 51 , 52, 53 for a stroke of greater width than the thickness of the web material 2, as well as to rotate the same joining assembly 5 according to a horizontal axis, parallel to the axis of the same rollers 51 , 52, 53, between a first and a second specular working position.

[50] The operation of the apparatus for automatically joining reels of web material is easily understandable from the following description.

[51] When it is detected, via special sensor means, known in the art, that the diameter of the running reel 21 has achieved a predetermined value, that is, that within a predetermined period of time the same running reel 21 will expire, the rotation of the new reel 22, previously set in the working position, is operated.

[52] It should be noted that in this phase, the counter-rotating rollers 51 , 52, 53 of the joining assembly 5 are arranged in the working position coplanar to the reels 21 , 22 of web material. Suitably, the rollers 51 , 52, 53 also have the same peripheral speed. The web material 2 unwinding from the first reel 21 sequentially engages these rollers 51 , 52, 53 of the joining assembly 5 and run freely therebetween, as can be seen in Figure 1.

[53] The second reel 22 is rotated at a peripheral speed, substantially equal to the unwinding speed of the web material 2 of the first reel 21 . During this step, the leading edge of the web material of the second reel 22 is wound and held close to the outer surface of the same second reel 22 by the vacuum vane 31 of the gripping member 3, operated in rotation integrally with the second reel 22.

[54] When it is detected that the first reel 21 is about to expire, the drawing means that put the outer surface of the first roller 51 under vacuum is actuated. In this way the web material 2 is retained on the vacuumed outer surface of the first roller 51 .

[55] In a suitable phase relationship, the cutting means 6 carried by the second conveying roller 52 is in a radial position with respect to the first unwinding roller 51 (Figure 5). At this moment, the blade 60 that performs the cutting of the web material 2 is actuated. The cutting of the web material defines, downstream of the cutting line, the trailing edge of the reel 21 which continues the forward movement on the second roller 52 to be then joined to the leading edge of the new reel 22 so as to make the feeding of the web material to the machine continuous. The residual web material, upstream of the cutting line, is instead retained on the first vacuumed roller 51 and is wound on the same first roller.

[56] The synchronized rotation of the rollers 51 , 52, 53 of the joining assembly 5 with the rotation of the new reel 22 allows to bring the trailing edge of the first reel 21 , in suitable phase relationship, in front of the leading edge of the new reel 22, carried by the vacuum vane 31 of the gripping member 3 (Figure 6). In this way, thanks to the label 4 of adhesive material, the joining of the two edges of the reels 21 , 22 is carried out.

[57] Suitably, in order to facilitate this joining operation, it is possible to provide that the vacuum vane 31 of the gripping member 3 is moved radially outwards with very limited amplitude to press the leading edge of the new reel 22 bearing the label 4 of adhesive material against the opposite trailing edge of the first reel 21 carried by the second roller 52.

[58] After joining the two edges of the reels 21 , 22, the web material 2 continues to travel on the third drive roller 53, unwinding from the second reel 22 (Figure 7). In practice, the web material 2 is tightned between the second and third drive rollers 52, 53, with a pressure suitably adjusted so as to prevent it from running with respect to the same rollers 52, 53. The passage of the web material 2 between the second and third rollers 52, 53 also has the function of compressing the label 4 of adhesive material to ensure its grip.

[59] Once the joining of the reels of web material has been completed, the movement of the movable assembly is operated, which brings the joining assembly 5 into a retracted position, such as to disengage the web material 2, as well as the rotation of the joining assembly 5 itself according to a horizontal axis in a working position specular to the previous one (see Figures 8-11 ).

[60] At the same time, the expired reel is automatically removed, in a known manner, from the hub 10 and a subsequent new reel 24 is inserted in its place (Figure 12). It should be noted that in the new configuration the rollers of the joining assembly 5 are turned towards the second reel 22, in a specular position to the previous one, i.e. rotated by 180°. The apparatus is thus prepared for the subsequent operation of joining the reels, so as to ensure continuous feeding of the web material to the machine.

[61] The method and apparatus for automatically joining reels of web material according to the present invention achieve the purpose of optimally carrying out the automatic joining of reels of web material in machines that use such web material for producing or packaging the products.

[62] In particular, it has been verified that the method and the apparatus for automatically joining reels of web material according to the present invention make it possible to ensure a high operating speed, so as to make the feeding of the web material continuous even in the case where the machine is configured to operate at a very high speed.

[63] This is made possible thanks to the inventive idea of equipping the reels of web material with a gripping member capable of retaining the leading edge of said web material close to the external surface of the reels carrying adhesive means suitable for joining the trailing edge of the expiring reels, as well as preparing a joining assembly which, with a specific command, is capable of separating the trailing edge of the web material from the expiring reel and applying this trailing edge to the end of the new reel, to perform automatic joining.

[64] Another feature of the invention is the fact that the apparatus described allows the joining assembly to be prepared for the subsequent step of changing the reels during the feeding of the web material by the running reel, so as to avoid downtimes or slowdowns in the joining of the edges of the reels and so making the feeding of the web material to the machine continuous.

[65] In practice, the apparatus adapts to the operating speed of the machine as the joining of the edges of the reels and therefore the change of the reels themselves is carried out on the web material that unwinds at the feed speed set by the machine.

[66] The apparatus described by way of example is susceptible to numerous modifications and variations according to different needs.

[67] In the practical embodiment of the invention, the materials used, as well as the shape and the dimensions, may be modified depending on needs.

[68] Should the technical features mentioned in any claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs.