Patent Publication Number: US-6655629-B1

Title: Apparatus and method for preparing winding mandrels and cores for rewinding machines

Description:
TECHNICAL FIELD 
     The present invention relates to an apparatus for preparing winding mandrels with corresponding tubular winding cores fitted on them for introduction into rewinding machines or other winding machines. 
     STATE OF THE ART 
     In various industrial sectors, for example in the paper converting industry, the textile industry and the production of nonwoven textiles, it is frequently necessary to wind on to rolls of smaller or larger diameter a web material taken from a reel of greater diameter. Frequently, a plurality of rolls of smaller height are formed simultaneously by winding strips of web material generated by longitudinally cutting a single strip taken from the reel of greater diameter. The strips are wound on tubular cores adjacent to each other and carried by an expanding winding mandrel. An example of a machine for carrying out this type of winding is described in EP-A-0747308. 
     In some cases, the rolls which are formed simultaneously on the cores fitted on to the mandrel have heights (in other words, axial lengths) which differ from each other. Usually, one or more operators prepare the tubular cores which have previously been cut from a continuous tube, fitting them on to one or more mandrels positioned outside the rewinding machine, and then, at the start of each winding cycle, insert the individual mandrels, fitted with the corresponding tubular cores, into the rewinding machine. This procedure is time-consuming, tiring, and labor-intensive. 
     Moreover, since the individual tubular cores fitted on each mandrel generally have different lengths from each other, errors may frequently occur as a result of the operator&#39;s failure to fit the cores in the correct order. Consequently there will no longer be a match between the sequence of the axial lengths of the tubular cores and the sequence of the transverse widths of the strips of web material which are fed to the mandrel for winding. 
     Furthermore, when this conventional procedure for preparing the mandrels is followed, the various tubular cores fitted on them are necessarily adjacent to each other. This means that the individual rolls which are formed on the mandrel are also necessarily adjacent to each other. This causes considerable problems, since the windings of one roll may interfere with those of an adjacent roll, giving rise to difficulties in the subsequent separation. The necessity of winding rolls on cores adjacent to each other entails further problems in cases in which the wound material is subject to shrinkage in respect of its width. This is because in this case there is a risk that the tubular cores will project from one or both ends of the finished roll, giving rise to difficulties in the subsequent operations of handling the rolls. 
     At the present time, if shrinkage of the wound material occurs during the rewinding stage, then, in order to prevent the projection of the cores from the finished rolls, the operator inserts a spacer between each core and the next in such a way that the cores remain inside the roll in each case. These spacers are in the form of open rings, to allow them to be inserted even when the cores have already been fitted on to the mandrel. The spacers are usually made from plastic material and are recovered at the end of the rewinding stage after the mandrel has been extracted. This system is unsatisfactory in that it is complicated, labor-intensive, and a source of errors on the part of the operator. 
     In rewinding machines of the aforementioned type, a set of cutters is placed upstream of the winding area in order to divide the web material taken from the reel into strips of the desired width. A computerized system is normally used to position the individual cutters correctly with respect to the transverse direction of the web material. The tubular cores, however, are cut to size (with core lengths which must match the widths of the individual strips into which the cutters divide the web material) in a different area of the plant, with a consequent risk of failure of matching between the positions of the cutters which cut the web material in the longitudinal direction and the axial dimensions of the individual tubular cores. 
     OBJECTS OF THE INVENTION 
     The object of the present invention is to provide an apparatus or device which makes it possible to overcome the disadvantages, the limitations and the possibilities of error of the conventional systems. 
     More particularly, a first object of the present invention is to provide a device and a method which permit the fast and accurate preparation of the mandrels with the corresponding tubular cores fitted on them for subsequent introduction into the rewinding machine. 
     A further object of the present invention is to provide a device and a method which make it possible to reduce the labor-intensiveness of cycles of winding or rewinding web materials. 
     Yet another object of the present invention is to provide a device and a method which make it possible to reduce or eliminate errors in the preparation of the mandrels for winding. 
     The object of an improved embodiment of the invention is to provide a method and a device which make it possible to automate the operations of preparing the cores and coordinating the cutting of the cores with the cutting of the web material, to achieve greater precision and speed. 
     An object of the present invention is also to provide a method and a device which avoid the disadvantages which are found in the rewinding of web materials which tend to shrink in the transverse direction, and also the problems arising from the difficulties of detaching rolls wound on adjacent cores carried by a single mandrel. 
     SUMMARY OF THE INVENTION 
     These and other objects and advantages, which the following text will make clear to those skilled in the art, are essentially achieved with a device comprising, in combination, an extraction station with an extractor mechanism for extracting a mandrel from one or more rolls of web material which has previously been wound and for inserting the extracted mandrel into a tube or core of cardboard or the like; a cutting station with cutting means for cutting the tube fitted on the mandrel, transforming it into a set of tubular cores aligned on the mandrel; and an insertion station with insertion members for inserting the mandrel with the tubular cores fitted on it into a rewinding machine or other winding machine. 
     These three stations enable the operations of preparing the tubular cores on the mandrel to be carried out in a partially or completely automatic way. 
     In the preferred embodiment of the invention, the three aforementioned stations are distributed spatially along a path which extends in a direction preferably orthogonal to the axis of the mandrel. This is particularly advantageous since it simplifies the design of the device and makes it possible to move the mandrel, while the tubular cores are being prepared on it, from the extraction position to the position of reinsertion into the rewinding machine, said two positions being normally spaced apart because of the presence of the winding members in an intermediate position. The use of three stations spaced apart also yields the advantage that it is possible to handle three mandrels simultaneously, one in the extraction station, one in the cutting station and the third in the insertion station. 
     On the other hand, the location of a plurality of stations, particularly two stations, in the same position in space is not excluded. For example, the cutting station can be spatially superimposed on or coincident with the extraction station, or the cutting station can be spatially coincident with or superimposed on the insertion station. 
     In a particularly advantageous embodiment of the invention, the extractor mechanism causes, by a single movement, the extraction of the mandrel from the finished roll or rolls and its insertion into the tube. On the other hand, the extraction from the finished roll or rolls and the insertion into a new tube by two separate movements is not excluded. 
     The extractor mechanism can be made with a pair of shaped wheels or rollers which are pressed against the outer surface of the mandrel and then made to rotate. Other systems of extracting the mandrel, for example by means of a pneumatic or hydraulic cylinder or the like, are not excluded. The use of powered shaped rollers makes the device particularly simple, economical and reliable, and also versatile in that it is easily adaptable to different mandrel diameters. It makes it particularly simple to insert the mandrel into a new tube at the same time as it is extracted from the finished roll. 
     Preferably, the mandrel used is of the expanding type, which is deflated before the extraction from the roll and re-inflated or expanded once it has been inserted into the tube. For this purpose, the extraction station comprises known means for deflating and inflating the mandrel. 
     In an advantageous embodiment, the extractor mechanism comprises a pair of shaped rollers which are pressed against the mandrel and made to rotate to move said mandrel in a direction parallel to its axis. This mechanism is particularly simple and enables the mandrel to be extracted and inserted into the tube efficiently, with a single movement. The shaped rollers can both be powered, but having one of them idle is not excluded. 
     A device for supporting the mandrels can advantageously be provided at the extraction station. In a possible embodiment, usable especially for long mandrels, the support device consists of a tube support cradle, made for example in the form of a roller train, a V-shaped section or the like. The support device, for example the aforesaid roller train, can be vertically movable so that it can be brought to a lower loading position, where it is easier to introduce the tube, and from there to an upper position for the insertion of the mandrel into the tube. The height of the second position is determined by the structure and size of the rewinding machine with which the device is associated. Advantageously, the positioning movement can be obtained by means of a gantry system with slides which move vertically along the uprights. 
     When the three stations, for extraction, cutting and insertion, are positioned so that they are separated from each other in space, means of transferring the mandrel from one to another will be provided. In a simple and economical embodiment, the transfer is carried out by rolling on inclined planes or rolling chutes. Suitable expulsion means, which push the mandrel, with the tube or tubular cores fitted on it, on to the corresponding inclined plane, are provided at the extraction station and/or at the cutting station. 
     The cutting station can comprise, in a possible embodiment, a pair of cylinders forming a cradle which supports the mandrel with the tube fitted on it for subsequent cutting into tubular cores. The rotation of the cylinders causes the mandrel supported on them to rotate correspondingly about its own axis. The possibility of imparting the rotary motion to the mandrel by other means, for example by means of a system of powered centers, is not excluded. The preferred system, with the pair of cylinders, is simpler in terms of construction and less critical in respect of tolerances. 
     The cutting station comprises one or more cutting heads, which in the preferred embodiment are located above the pair of cylinders, and each of which carries a cutting tool, preferably consisting of a discoid blade. The latter is preferably a smooth-edged blade and is idly supported. 
     The cutting tool is advantageously carried by an oscillating arm which controls its movements toward and away from the mandrel, although the possibility of using mechanisms of another type for moving the cutting tools toward and away from the mandrel is not excluded. The use of an oscillating arm is particularly advantageous in terms of mechanical simplicity. Additionally, in this way it is easy to provide a system of stops which define the operating position, in other words a plurality of operating positions of the tools, which can be selected alternatively according to the diameter of the mandrel and therefore of the tube to be cut. 
     Further advantageous characteristics and embodiments of the device according to the invention are described in the attached dependent claims. 
     The method according to the invention comprises the stages of extracting a mandrel from a roll or from a plurality of rolls formed in a rewinding machine or other; inserting the mandrel into a tube and fixing the tube with respect to the mandrel; cutting the tube fitted on the mandrel into a plurality of tubular cores aligned along said mandrel; and inserting the mandrel with the tubular cores fixed on it into a rewinding machine or other winding machine for the formation of rolls of web material on the individual cores. 
     In a particularly advantageous embodiment of the method according to the present invention, the mandrel is simultaneously extracted from the roll or rolls and inserted into the tube. Further advantageous characteristics of the method according to the invention are indicated, in the attached claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more clearly understood from the description and the attached drawing; which shows a nonrestrictive embodiment of the invention. More particularly, the drawing shows: 
     FIG. 1, a schematic side view of the device according to the invention; 
     FIG. 2, a schematic plan view according to the line II—II in FIG. 1; 
     FIG. 3, a detail view according to the line III—III in FIG. 2; 
     FIG. 4, a front view according to IV—IV in FIG. 1; 
     FIG. 5, a section through V—V in FIG. 4; 
     FIGS. 5A and 5B, enlarged side views of a head of the cutting station in two different configurations, corresponding to two different diameters of the mandrel and of the tube fitted on it; 
     FIG. 6, a view according to VI—VI in FIG. 4; and 
     FIG. 7, a schematic cross section of an expanding mandrel usable in a device according to the invention. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     The device according to the invention is placed next to a rewinding or winding machine suitable for operation with expansion mandrels of a known type. In the attached drawing, the only parts of the rewinding machine which are indicated are two lower winding rollers  1  and  3  (see FIG. 2) and corresponding drive motors of the winding rollers, indicated by  5  and  7 . The rewinding machine can be of any type, and by way of example it can be of the type described and illustrated in EP-A-0747308. However, it should be understood that the device according to the invention can be used with any winding system in which it is necessary to prepare a plurality of tubular cores on a common mandrel which is subsequently introduced into the winding area of the rewinding machine or other winding machine. 
     Schematically, the device according to the invention is divided into three stations, which are indicated in a general way by  9 ,  11  and  13  in FIGS. 1 and 2. The station  9  is a station for extracting the mandrel from a set of finished rolls aligned along the mandrel and produced by the rewinding machine, these rolls being partially visible in FIG.  1  and indicated therein by R. At the station  9 , the mandrel which is extracted from the set of finished rolls is simultaneously inserted into a tube T which is fed to the device in the way described below by an operator or by an automatic loader. 
     The station  11  is a cutting station, in which the tube T fixed on the mandrel, which has been expanded at the station  9 , is cut into a plurality of shorter tubular cores, matching the heights of the rolls which will be produced subsequently by the rewinding machine. 
     The station  13  is a station for inserting the mandrel, with the tubular cores cut to size and fixed on it, into the rewinding machine. 
     The three stations  9 ,  11  and  13  and their operation will be described individually in greater detail in the following text. 
     The station  9  has a gantry structure  15  comprising two uprights  17  linked by a crossbeam  19 . Guides  21  extend along the uprights  17  to allow the sliding of two slides  23  which carry a beam structure  25  on which is mounted a roller train  27  which forms a cradle to accommodate a tube T, whose axial length is equal to the sum of the lengths of the individual tubular cores, and any necessary intermediate spacers, on which the rolls are formed simultaneously by means of the rewinding machine. The slides  23  are moved as shown by the arrow F 23  (FIG. 1) along the guides  21  by means of a motor  29  associated with one of the uprights  17 , using a recirculating ball screw system or equivalent (not shown). The roller train  27  can be brought by this vertical movement to a lower height, indicated in broken lines in FIG. 1, to which the operator can easily carry the tube T without having to raise it to an excessive height. The operation of loading the tube T can be automated by providing for the use of a suitable loader. 
     The subsequent raising of the roller train  27  brings the tube T to the height corresponding to that of the axis of the set of rolls R which have been produced by the rewinding machine and are ready to be discharged. This position is shown in solid lines in FIG.  1 . 
     The gantry  15  is mounted on a carriage  20  movable on a pair of guides  22 . The movement along said pair of guides is obtained by means of a pinion and rack system  24 ,  26  and is provided by a motor which is not shown. The movement of the gantry  15 , the slides  23  and the roller train  27  in the direction of the guides  22  as shown by the arrow F 25  enables the roller train to be brought up to and away from the rewinding machine where the roll R from which the mandrel has to be extracted is located. This makes it possible to provide a shorter roller train. Alternatively, the gantry  15  can be made to be fixed and the roller train can be made to have a greater longitudinal extension. 
     An extractor mechanism  31 , used to extract the mandrel from the set of finished rolls R and to insert it by the same movement into the tube T, is provided in a fixed position, or preferably carried on the beam  25 . The extractor mechanism  31  has (see also FIG. 3) a pair of shaped rollers  33  covered with rubber or other material with a high coefficient of friction. Each shaped roller  33  is driven by a corresponding electric, pneumatic or hydraulic motor  37 . Each assembly formed by a shaped roller  33  and the corresponding motor  37  is carried by a slide  39  which is movable along guides  41  so that it can be brought up to the mandrel  35 . Cylinder and piston actuators, indicated schematically by  42 , impart the movement to the slides  39  along the guides  41 . This enables the shaped rollers  33  to be pressed against the mandrel regardless of its diameter. 
     The shaped rollers  33  are made to rotate in the directions shown schematically by the arrows in FIG. 2 (where the mechanism  31  is represented schematically). As a result of the friction between the surface of the mandrel  35  and the shaped surface of the rollers  33 , the mandrel  35  (which has previously been deflated) is extracted from the rolls R by a movement as shown by the arrow F 35 . Since a new tube T has been previously positioned on the roller train  27 , the movement of extraction of the mandrel  35  produced by the shaped rollers  33  causes the simultaneous insertion of the mandrel into the new tube T. 
     When the mandrel  35  has been inserted into the new tube T, it is inflated, in other words expanded in such a way that the tube T is fixed on it. The extraction station  9  is provided with means of deflating the mandrel before the extraction from the rolls R and means for the subsequent inflation or expansion after it has been introduced into the tube T. These means, which are known, are not represented in the drawing. 
     When the tube T has been fixed on the surface of the mandrel  35 , the operator, or a suitable mechanical expulsion device, pushes the assembly formed by the mandrel  35  and the tube fitted on it along a rolling plate  43  or chute into the cutting station  11 . 
     The cutting station  11  has a pair of cylinders  51  with parallel axes, forming a cradle which supports the mandrel  35  with the tube T fitted on it which arrives from the extraction station  9  by rolling as shown by the arrow FT along the rolling plane  43 . The two cylinders  51  are rotated by a motor  52  carried by one of the two sides  55  of the cutting station  11 . 
     A crosspiece  53  carried by the sides  55 , on which two guides  57  are provided, extends above the cylinders  51 . Two heads  59 , which can move as shown by the arrow F 59 , run on the guides  57 . The heads  59  are moved by two corresponding threaded bars  61  interacting with two nuts  62  carried by the heads  59 . The number  63  indicates the motors which rotate the threaded bars  61 . These bars are positioned at two different heights to enable the two heads to move along paths which partially overlap in the central area of the crosspiece  53 . 
     Each head  59  comprises (see in particular FIGS. 5,  5 A and  5 B) a slide  65  which can run on the guides  57  and carries a support  67  for an oscillating arm  69  carrying a cutting tool consisting of a discoid blade  71  which is free-running on a shaft  73  held by a fork  69 A of the arm  69  (see FIG.  4 ). A cylinder and piston actuator  75  provides the oscillatory movement of the arm  69  about the support  67  to bring the discoid blade  71  alternately to an operating position and a nonoperating position. The oscillating arm  69  is integral with a bracket  77  on which is pivoted the cylinder of an air spring consisting of a cylinder and piston unit  79 . The rod of the cylinder and piston unit  79  is pivoted on a rocker  81 , which in turn is pivoted at  83  on a second bracket  85  carried by the oscillating arm  69 . A pressure roller  87  is carried on the rocker  81  for the purposes indicated below. 
     A bracket  66  (visible in FIGS. 5,  5 A and  5 B), which carries a pair of adjustable stops  68 A,  68 B, is integral with the slide  65  of the head  59 . The stop  68 A interacts with a pin  68 C fitted to the oscillating arm  69 , while the stop  68 B interacts with the arm  69  itself. The stop  68 A is made inactive by removing the pin  68 C. Thus the limit position (in other words the position of maximum oscillation in the clockwise direction) of the arm  69  will be determined by the stop  68 A when the pin  68 C is fitted to the arm  69 , while it will be determined by the stop  68 B when the pin  68 C is removed from the arm  69 . FIGS. 5A and 5B show in an enlargement the two different configurations of the stops for the cutting tool in the cases of mandrels having a small diameter (FIG. 5A) and a large diameter (FIG.  5 B). In FIG. 5A, the pin  68 C has been taken out, and the operating position of the cutting tool is determined by the stop  68 B. 
     Each of the two sides  55  carries vertical guides  89  along which run corresponding plates  91 , each carrying a center  93 . The two centers  93  are aligned axially and their position can be adjusted in the vertical direction by means of corresponding actuators  95  carried by the sides  55 . The actuators  95  move the plates  91  along the sliding guides  89  carried by the sides  55 . Additionally, each center  93  is associated with a corresponding short-travel cylinder  97  which causes the corresponding center  93  to move in the, axial direction to move the centers  93  toward and/or away from each other. 
     A pair of expulsion arms  99  located outside the maximum dimensions of the cylinders  51  can oscillate about the axis  51 A of the cylinder  51  which is furthest from the rolling plane  43 . FIG. 5 shows one of the expulsion arms  99  in a first position, in which it is under the cradle formed by the rollers  51 . FIG. 4 shows both of the expulsion arms  99  in a position elevated above the cylindrical surfaces of the cylinders  51 . The oscillatory movement of the expulsion arms  99  is controlled by a cylinder and piston actuator  100 , or—as shown in FIG.  4 —by a pair of symmetrical actuators, again indicated by  100 . The expulsion arms  99  are connected by a torsion bar  101 . 
     The operation of the cutting station  11  is as follows. When a mandrel  35  with a tube T fitted on it reaches the cradle formed by the cylinders  51  by rolling on the rolling plane  43 , it is fixed axially by means of the centers  93  which are brought toward each other by means of the short-travel cylinder  97 . The centers  93  have previously been positioned in the vertical direction by the cylinder and piston actuators  95  so that they are located in the correct position according to the diameter of the tube T and the mandrel  35 . It is also possible for one of the centers  93  to be axially movable and for the other to be fixed, and therefore without the short-travel cylinder  97 , and for the movement of approach to each other to be carried out by the first center only. The centers are free to rotate about their own axes, which coincide with the axis of the mandrel  35 . 
     When this configuration has been reached, the cylinders  51  are rotated by the motor  52 . The starting of the rotation of the motor  51  before the positioning of the mandrel  35  in the cradle formed between them is not excluded. The heads  59  are brought (by a movement along the guides  57  by means of the threaded bars  61 ) to the positions in which the tube T is to be cut to form the tubular cores. During this movement, the oscillating arms  69  are kept in the raised position so that the discoid blades  71  do not interfere with the mandrel and the corresponding tube T lying below them. When it reaches the position in which the circumferential cut of the tube T is to be carried out, the head  59  is fixed and the oscillating arm  69  is lowered toward the cradle formed by the cylinders  51 . 
     By this movement, the pressure roller  87  comes into contact with the outer surface of the tube T before the discoid blade  71 . This provides the pressure between the tube T and the cylinders  51  necessary to keep the tube and the mandrel  35  fitted inside it in rotation by the effect of friction. As the downward movement of the arm  69  continues, the air spring  79  is compressed until the discoid blade  71  comes into contact with the tube T to be cut and passes through its thickness. The air spring  79  therefore also acts as a damper of the movement of the arm  69 . The final position of the discoid blade  71  is determined by the stop  68 A or  68 B, as mentioned above, and is selected in such a way that the discoid blade  71  does not cut into the mandrel  35  which is located inside the tube T. 
     In the example in FIG. 5, the operating position is determined by the stop  68 A. The head  59  maintains this position until the cutting of the tube T has been completed, after which the arm  69  is raised and the head is made to move to the next cutting position. 
     The operation is repeated for the requisite number of times, according to the number of tubular cores which are to be produced by cutting the tube T. It is possible to provide for the formation, between two adjacent cores, of a spacer ring formed by two consecutive circumferential cuts. In this way the consecutive tubular cores, on which the rolls of web material will be generated in the rewinding machine, can be kept separate from each other, thus preventing the finished rolls from having (as a result of the reduction of width of the web material) tubular cores which are longer than the heights of the rolls and consequently project from the rolls. 
     The cutting positions entered sequentially by the heads  59  can be controlled by a central control unit interfaced with the rewinding machine in such a way that there is an automatic co-ordination between the cutting positions of the heads  59  (and consequently the sizes of the tubular cores on the mandrel  35 ) and the positions of the cutters of the rewinding machine which carry out the continuous longitudinal cutting of the web material taken from the reel. 
     When the tube T has been completely divided into the various tubular cores, the assembly consisting of the mandrel  35  and the tubular cores fitted on it is discharged on to an inclined discharge plane  121  so that it reaches a channel  123  formed by the pair of V-sections forming part of the insertion station  13 . The channel  123  is associated with a cylinder and piston actuator without a rod  125 , provided with a pusher  127 . The cylinder and piston actuator  125  pushes the mandrel  35  into the rewinding machine, where it undergoes a rewinding cycle of a known type. 
     The discharge of the assembly consisting of the mandrel  35  and the tubular cores from the cradle between the cylinders  51  of the cutting station  11  is carried out by the oscillation of the expulsion arms  99  about the axis  51 A. 
     The expanding mandrels may be of any shape. A detailed description of this member is not necessary, since it is of a known type. Purely by way of example, FIG. 7 shows a cross section of a possible expanding mandrel. This has a tubular element  150  with three slots extending in the axial direction and through which there extend corresponding stems  152  of expanding shoes  153 , each of which has, at the radially outer end of the stem  15 , a shell which extends in the form of a portion of a cylindrical surface. At the radially inner end of the stem  152 , there is base element  154  which rests on a tubular air chamber  155  inside the element  150 . A rubber sleeve  157 , which forms the outer surface of the mandrel  35 , is provided around the shells  153 . In FIG. 7, the mandrel is shown in its expanded position, with the shells  153  in their radially outward position, the air chamber  155  being inflated. The mandrel is deflated by removing the excess pressure in the chamber  155 . The radial retraction of the shells  153  is caused by the elasticity of the outer tubular sleeve  157 . This sleeve can be replaced rapidly in case of wear, particularly if wear is caused by the cutting edges of the discoid blades  71 . 
     It is to be understood that the drawing shows only a possible embodiment of the invention, which can be varied in its forms and arrangements without departure from the inventive concept on which the invention is based. The presence of any reference numbers in the attached claims does not limit the scope of protection of the claims, but has the sole purpose of facilitating the reading of the claims with reference to the preceding description and of the attached drawings.