Abstract:
A drum for cutting linerless labels from a continuous strip and transferring the labels to a container movable with a given trajectory and speed on a machine, the drum including a side surface suitable for guiding the strip by contacting a non-adhesive surface of the labels, the side surface defining a vertical slit, a coaxial and concentric sleeve for centering the drum on a corresponding support spindle, a cutting blade parallel to a vertical direction of the drum, the cutting blade being displaceable in a radial direction from a position retracted inside the drum to a position at least partially extended through the vertical slit outside the side surface of the drum, a fixed cam relative to which the drum rotates and that is configured to press against the cutting blade so as to cause the cutting blade to extend out in a predefined angular position, and a seat that extends in the vertical direction (Z-Z) and is connected to the cam and which is suitable for engagement with a corresponding fixed reference pin in order to determine a predefined angular position of the cam, wherein the drum is configured to retain the strip against the side surface of the drum.

Description:
CROSS-REFERENCE TO RELATED ACTIONS 
     This application claims the benefit of and priority to Italian Patent Application No. MI2010A001293, filed Jul. 14, 2010, which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     It is known in the technical sector of packaging that there exists the need to apply onto each product container a corresponding identification label. Also known are apparatus which are able to transfer onto the container individual self-adhesive labels which are mounted on a backing strip and wound on a reel, by means of programmed and controlled unwinding of the said reel and transfer of a label onto the corresponding container which is moving on an associated labeling machine. In this technical sector also well known are so-called “linerless” labels or labels that are not mounted on a backing strip that must be separated from the label when the latter is applied and recovered separately for disposal thereof. These “linerless” labels essentially consist of a single sheet of suitable material, one of the opposite surfaces of which is provided with an adhesive layer for gluing to the container, while the opposite surface is lined with a transparent and non-adhesive varnish designed to prevent adhesion of the continuous strip when wound onto itself. The continuous strip can also be provided with (pre-cut) perforations forming preferential cutting lines suitable for separation of each label from the ones adjacent thereto. 
     Reference WO 2009/030893 discusses a method and an apparatus for transferring linerless labels to a container moving on a labeling machine along a given path associated with the machine. The apparatus is based on the use of a silicone-lined transfer belt which rotates in a closed loop around two rollers and which conveys the continuous strip of labels in a direction inclined at a suitable angle relative to the plane of displacement of the product onto which the label must be applied. This relative angle essentially allows the label, which advances together with the transfer belt, to come into contact tangentially with the container and, when it adheres by means of contact to the container, to be cut along pre-cut lines by a fixed blade arranged upstream and perpendicular to the belt itself. Although fulfilling its function, this apparatus nevertheless has a number of drawbacks associated mainly with the fact that the labels made of soft and/or thin material tend not to separate from the transfer belt in a reliable and highly repeatable manner, said separation being determined by the radius of curvature of the transfer belt which cannot be reduced beyond a certain limit value. 
     In addition, it has been found that the surface of the belt, to which the label is attached, tends to become soiled over time, resulting in an unstable relative contact between belt and label. This can cause, at the moment of separation, an incorrect angle with respect to the belt, with the result being that the label is positioned crookedly on the finished product. Moreover, this solution requires that the labels be made of materials that are so rigid that they are unable to follow the small angle of curvature of the drive belt and therefore become separated from it. 
     The fixed position of the cutting blade moreover has the effect that it is not possible to cut labels with a certain margin of tolerance in terms of their longitudinal dimension. These drawbacks also mean that with the known apparatus it is not possible to reach the high speeds at which the containers travel on most recent labeling machines, said apparatus thus being essentially unsuitable for the present-day production/packaging cycles. 
     SUMMARY 
     In general, in an aspect, embodiments of the invention can provide a drum for cutting linerless labels from a continuous strip and transferring the labels to a container movable with a given trajectory and speed on a machine, the drum including a side surface suitable for guiding the strip by contacting a non-adhesive surface of the labels, the side surface defining a vertical slit, a coaxial and concentric sleeve for centering the drum on a corresponding support spindle, a cutting blade parallel to a vertical direction of the drum, the cutting blade being displaceable in a radial direction from a position retracted inside the drum to a position at least partially extended through the vertical slit outside the side surface of the drum, a fixed cam relative to which the drum rotates and that is configured to press against the cutting blade so as to cause the cutting blade to extend out in a predefined angular position, and a seat that extends in the vertical direction (Z-Z) and is connected to the cam and which is suitable for engagement with a corresponding fixed reference pin in order to determine a predefined angular position of the cam, wherein the drum is configured to retain the strip against the side surface of the drum. 
     Implementations of the invention can provide one or more of the following features. The side surface of the drum defines a plurality of holes, and the drum further includes a plurality of channels that connect the plurality of holes to a suction device such that air is sucked in towards the inside of the drum thereby retaining the strip. The cam is mounted inside the drum. The cam is of the double track type suitable for pushing/recalling the blade. The drum further includes a spring configured to recall the blade into the retracted position. The drum further includes a plurality of cutting blades arranged at a predefined constant angular distance. The side surface has at least one buffer element made of resilient material and arranged downstream of each blade and is able to come into contact with the surface of the container substantially at the moment of impact with the label. The drum further includes at least one reference notch suitable for being detected by a fixed sensor for determination of a start-of-cycle position of the drum. 
     In general, in another aspect, embodiments of the invention can provide an apparatus for applying linerless labels from a continuous strip onto a container movable with a given trajectory and speed on a machine comprising at least one drum, as described herein, for cutting and transferring the labels. 
     Implementations of the invention can provide one or more of the following features. The apparatus according further includes a first unit for unwinding the continuous strip of labels and a second unit for driving the strip, the first and second units are arranged in series with each other and upstream of the drum. The first unit for unwinding the strip includes a vertical-axis reel on which the strip is wound, a plurality of transmission rollers, at least one jockey roller for tensioning the strip, and a motor for rotationally actuating the reel. The second unit driving the strip includes a vertical-axis cylinder associated with a roller to which it is connected via belts angularly arranged so as to produce a tangential orientation of the strip leaving the drive unit relative to the transfer drum, a motor for rotationally actuating the cylinder, and a sensor arranged tangentially with respect to the drive cylinder for detecting reference marks printed on the strip. The drive cylinder is associated with jets of air supplied to the annular grooves of the drive cylinder and designed to press the strip against the drum. The drive cylinder is rotationally actuated in a discontinuous start/stop sequence. The drive cylinder is rotationally actuated in a continuous manner at a variable speed. The strip moves in synchronism with the drum and the product. The side surface of the drum has at least one buffer element made of resilient material and arranged downstream of each blade and able to come into contact with the surface of the container at the moment of impact with the label. The drum rotates synchronized in terms of its position and with a tangential speed, in the angular position of impact of the label with the container, equal to the tangential speed of the container itself. The drum rotates synchronized in terms of its position and with a speed equal to the speed of the machine. The drum rotates synchronized in terms of its position and with a speed which is different from the speed of the machine, wherein the speed is variable with acceleration/deceleration ramps. The drum rotates synchronized in terms of its position and with a speed which is different from the speed of the machine, namely in start/stop manner with acceleration/deceleration ramps. The drum rotates with a speed of rotation equal to the sum of the speed of the machine and a predefined speed of rotation of the container about its vertical axis. The drum has a plurality of cutting blades arranged in an angular position defined by the geometrical configuration of the labeling machine. The apparatus according further includes an air suction device in communication with a plurality of holes defined in the side surface. The apparatus is mounted on a support base. 
     In general, in yet another aspect, embodiments of the invention can provide a method for cutting linerless labels from a continuous strip and transferring the labels to a container movable with a given trajectory and speed on a container-conveying machine, the method including providing a drum, as described herein, rotating synchronized in terms of its position and with a tangential speed equal to the tangential speed of the container itself at the angular position of impact of the label with the container, feeding a strip of linerless labels to the drum with start/stop mode advancing of the strip, retaining the strip of labels with relative contact between the side surface of the drum and the non-adhesive side of the labels, sending, by the container-conveying machine, a consent signal indicating the presence of a container at a predefined distance from the angular position of impact with the label, synchronizing the advancing of the strip so as to position the first label at the point of impact with the container, impacting the label and the container, extending the cutting blade from the drum, tensioning of the strip by the container, separating the label from the strip, and completing adhesion of the label on the container. 
     Various aspects of the invention may provide one or more of the following capabilities. An apparatus for the application of linerless labels onto moving containers, which is able to solve the technical problems mentioned above can be provided. A device having small dimensions can be provided. A device that is easy and inexpensive to produce and assemble and is able to be installed easily on pre-existing machines, without the need for excessive special adaptation, can be provided. A drum for cutting linerless labels from a continuous strip and transferring them onto a container movable with a given path and speed on a labeling machine can be provided. 
     These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows a partially exploded perspective view of an apparatus with the cutting and transfer drum partly sectioned. 
         FIG. 2  shows a perspective view of the apparatus of  FIG. 1  with the cutting and transfer drum mounted. 
         FIG. 3  shows a perspective view of the apparatus shown in  FIG. 2 . 
         FIG. 4  shows a top plan view of the apparatus according to  FIG. 2 . 
         FIGS. 5-7  show partial views, from above, of the apparatus during various operating stages. 
         FIG. 8 , shows a front view of a further example of a label that can be applied by means of the apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention provide techniques for providing a drum for cutting and transferring linerless labels from a continuous strip to a moving container and an apparatus for applying linerless labels to moving containers, provided with said drum. Other embodiments are within the scope of the invention. 
     As shown in  FIG. 1  and  FIG. 4 , and assuming solely for the sake of convenience of description and without any limitation of meaning a set of three reference axes in a longitudinal direction X-X, corresponding to the direction of extension of a continuous strip of linerless labels, transverse direction Y-Y, and vertical direction Z-Z, respectively, as well as a front side corresponding to the side where the label leaves the apparatus and a rear side opposite to the front side. 
     The apparatus preferably includes a unit  100  for unwinding a continuous strip  1  of labels  2  of the linerless type with a rear adhesive surface  2   a  and a front non-adhesive surface  2   b . The strip also preferably has perforations (pre-cuts)  1   c  extending parallel to the vertical direction Z-Z and arranged at constant intervals along the longitudinal extension of the strip  1  so as to separate the individual labels  2  and form pre-weakened cutting lines. The strip  1  can also be provided with printed reference marks  1   d  as shown in the example of  FIG. 1 , on either side of the pre-weakened cutting line. The reference marks can be, for example, suitable for being detected by a sensor as will be descried more clearly in the description below. 
     The apparatus preferably also includes a unit  200  for driving the strip  1 , a drum  300  for cutting and transferring the individual labels  2  onto the respective container  3  (e.g., as shown in  FIG. 5 ) which travels along a given path on a machine  4 , which may be equally well of the rotating type (e.g., as shown) or linear type, and on which a surface  3   a  for application of a label is provided. 
     In greater detail, the unit  100  for unwinding the strip  1  preferably comprises a vertical-axis reel  110  onto which the strip  1  is wound, a plurality of transmission rollers  111 , and at least one jockey roller  112  for tensioning the strip during unwinding thereof. The unit  100  also preferably includes a motor  113  for driving the reel, via which it is possible to maintain the correct tension of the strip  1  during unwinding thereof. 
     The unit  200  for driving the strip  1  preferably comprises a vertical-axis cylinder  210  associated with a roller  211  to which it is connected by means of belts  212  which are housed inside associated annular grooves  210   a  and  211   a  on the cylinder  210  and the roller  211 , respectively. The belts  212  preferably assume an angular position such as to determine a tangential orientation of the strip  1  leaving the drive unit relative to the label transfer drum  300  described below. The unit  200  also preferably includes a motor  213  for rotationally actuating the cylinder  210  with start/stop operation, and a photocell  215  arranged tangentially with respect to the drive cylinder  210  for detecting reference marks  1   d  printed on the strip. 
     The label transfer and cutting drum  300  preferably comprises an outer side surface  301  provided with through-holes  301   a  and a first coaxial and concentric sleeve  310  for centering the drum on an associated spindle  311  supporting the said drum. Both the sleeve  310  and the spindle  311  can have a cylindrical or grooved engaging surface. In its bottom part, according to the layout shown in  FIG. 1 , the first sleeve  310  can have at least one seat  312  extending in the vertical direction Z-Z and suitable for engagement with a corresponding fixed reference pin  313  so that the pin/seat connection determines predefined angular positioning of a cam  320  which is fixed with respect to the drum  310  which rotates coaxially relative thereto. 
     In the example shown in  FIG. 1  the cam  320  can be arranged on the top front surface  312   a  of the first sleeve  310  and have a pressing surface  320   a  able to act by means of special connection elements  321  (conventional per se and therefore not described in detail) on at least one cutting blade  330  parallel to the vertical direction Z-Z and housed inside corresponding vertical slits  302  on the side surface  301  of the drum. Owing to the interaction with the cam  320 , the blade  330  can be displaceable, in a radial direction, from a position retracted inside the drum into an extracted position outside the side surface of the drum. The angular position of the cam can therefore define the angular position for cutting the label in relation to the length, in the longitudinal direction X-X, of the label to be applied. 
     Springs  334  can be fastened at their first ends to the same cam/blade connection elements  321  and can be fixed at their other end (e.g., as shown in the example) to a second sleeve  333  for centering the drum, which can be coaxial with the first sleeve  310 . The springs  334  preferably being able to recall the blade  330  into its retracted position. 
     Downstream of each blade  330 , the side surface  301  of the drum  310  preferably has buffer elements  303  that are made of resilient material and are able to come into contact with the surface of the container in order to take up any excess play in the transverse dimensions of the container. The inside of the drum can also be provided with channels  350  which can be connected to corresponding suction means (not shown) for creating the vacuum on the surface  301  of the drum. The drum can have associated with it, via the spindle  311 , a corresponding motor  336  that is able to keep the drum itself rotating constantly about the cam  320 . 
     In a preferred embodiment, it is envisaged that the apparatus is associated with a device  500  for programming and controlling the motors, the various detection sensors and the corresponding operating sequences. For example, the device  500  can be a conventional computer. 
     It is also envisaged that the device  500  can be connected to a fixed sensor (not shown) for detecting a reference notch on the drum  300  in order to determine the angular position of the latter and be able to bring it into the correct position for synchronization with the product to be labeled. During application of the label, feeding of the strip  1  will preferably also be synchronized with the product to be labeled so that extraction of the blade, which preferably always occurs in the same angular position upon operation of the fixed cam, corresponds to the passing movement of the pre-cut line  1   c  in front of the said angular position where extraction of the blade occurs. 
     All the parts described above are preferably mounted on a single support  10 . 
     With this structure the operating principle of the apparatus can be as follows. The drum  300  can be prepared so as to correspond to the height of the label  2  in the direction Z-Z and its length in the direction X-X. The apparatus can be installed opposite the machine  4  for moving the container  3  so that, at the point of application of the label  2 , the side surface  301  of the drum is tangential to the surface  3   a  of the moving container (shown rotating in the illustrative example) along a predefined path on a labeling machine  4 . The strip  1  can be manually prepared by unwinding it from the reel  110  until the first label is situated opposite the sensor  215  of the drive cylinder  210 . The control unit  500  can be used to set, as main parameters, the length of the label  2  in the longitudinal direction X-X and the speed of rotation of the drum  300  so as to correspond to the speed of the machine  4 . In this case, the blade interval of the drum can be equivalent to the product interval on the machine. The drive motor  213  can be operated manually so that the strip  1  advances along its path around the drive cylinder  210 , causing reversal of the opposite surfaces  2   a ,  2   b  of the label  2  which reaches the drum  300  with its non-adhesive surface  2   a  directed towards the side surface  301  of the drum and adhesive surface  2   b  directed outwards. In this way, continuing its feeding movement, the strip  1  can be removed from the drum  300  retaining it by means of suction via the holes  301   a.    
     Then, when the labeling machine  4  starts to rotate about its axis, the control unit  500  can cause rotation of the drum  300 , synchronizing the movement of the latter with the speed and the position of the product  3  to be labeled. In this way the contact surfaces of the drum and the product  3  to be labeled can have the same tangential speed and arrive correctly and synchronized at the impact point. Preferably, when the container  3  is close to the labeling position, the labeling machine  4  can send a consent signal to the control unit  500  of the apparatus that can operate the drive  200  so as to feed the strip  1  until it reaches the speed of the product to be labeled. During synchronized feeding of the strip  1  the first front label  2  can be situated at the point of impact with the container  3  to which it starts to adhere and from which it starts to be removed in synchronism. In this instant, the container  3 , the drum  300 , and the strip  1  preferably have the same speed. 
     Simultaneously, the cam  320  preferably causes extraction/extension of the blade  330 , which in that moment passes the angular position opposite that the pre-weakened perforated line  1   c  of the strip  1  also passes. Consequently, the container, which continues its movement along its path, draws along with it the label  2  and the latter is cut and separated easily and in a reliable manner from the strip  1  opposite the blade  330  only after adhering to the product. In this way, the label can adhere completely to the container, optionally being assisted by a smoothing device (not shown). 
     Subsequently, the sensor  215  of the drive cylinder can detect the reference notch  1   d  on the strip  1 , causing stoppage of the drive unit  220 , which also stops the strip, preparing it so that it is ready to start for the next application, while the drum  300  continues its rotational movement with a speed and position synchronized with that of the machine  4 . Continuing its rotation, the drum can cause rotation of the element  321  which, continuing to adhere to the cam  320 , allows the blade  330  to be recalled inside the drum by the action of the springs  334 , being prepared for the next cut. 
     One exemplary method is therefore described how the drum for cutting and transferring linerless labels and an associated apparatus provided with the drum are able to provide a solution to the technical problems of the prior art, allowing flexible and thin labels to be applied at a high speed since the labels are held on the drum by means of their non-adhesive surface, ensuring precise and square positioning and safe and repeatable separation at the moment of impact with the container. 
     In addition to the above, with the apparatus described herein, it is possible to apply in a fast, safe and repeatable manner also shaped linerless labels  102  of the type shown in  FIG. 8 , in strip form  101 , application of which is at present considered to be extremely problematic. 
     With the drum  300  as described changing of the format may also be performed in an extremely quick and easy manner since it is possible to provide a cutting and transfer drum for each series of homogeneous labels. The drum being replaced when there is a variation in the type of label, thereby reducing the downtime of the apparatus and therefore of the labeling machine. 
     A number of variations of embodiments of the apparatus are also envisaged. For example, the drum  300  can rotate at a speed different from that of the machine, namely continuously with a variable speed comprising acceleration/deceleration ramps for recovering any difference between the angular distance of the blades and the interval of the products to be labeled. The drum  300  can rotate at a speed different from that of the machine and in a discontinuous start/stop manner with acceleration/deceleration ramps. The speed of rotation of the drum  300  can be equal to the speed of rotation of the machine plus the speed of rotation of the container about its vertical axis, allowing the application of labels that are longer in the longitudinal direction onto containers that are larger without any variation in the advancing speed of the machine  4 . The drum can have a plurality of cutting blades  330  which are arranged in an angular position defined by the geometrical configuration of the labeling machine (e.g., pitch diameter and number of container-support discs  3 ) so that cutting occurs several times during each complete rotation of the drum. The blade extraction cam  320  can be provided with a double track so that it is possible to perform both extraction and retraction of the blade  330 . Air jets can be supplied to the annular grooves  212   a  of the drive cylinder  210  so as to push the strip  1  against the drum  30  for equivalent transfer of the strip  1  from the drive cylinder  210  onto the drum  300 . The drive cylinder  210  can be rotationally driven continuously at a variable speed so as to reduce downtime. 
     Other embodiments are within the scope and spirit of the invention. For example, due to the nature of software, functions described above can be implemented using software, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. 
     Further, while the description above refers to the invention, the description may include more than one invention.