Abstract:
The invention relates to a labeler and a method for applying labels onto an article strip, wherein a transfer device is moved continuously when said labels are pressed on and a lifting device of said transfer device comprises a height-adjustable actuator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority to European Application Number 12003976.3 filed May 22, 2012, to Georg Austermeier and Tanja Jansen entitled “Labeler and Method for Labeling,” currently pending, the entire disclosure of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a labeler as well as to a method for labeling. 
     BACKGROUND OF THE INVENTION 
     A labeler is known from DE 10 2008 007 890 A1 for applying labels in rows on a film sheet. In this, the labeler is arranged on a thermo-forming packaging machine downstream of a sealing station, and it can apply the labels from the top onto a cover film, or from below onto the bottom surface of a formed lower film of a pack. The film strip comprises a plurality of tracks and a plurality of rows of packs. A transfer device of the labeler picks up a number of labels from a label dispenser, while a lifting device of the transmission device is in a first position spaced from the film strip. The transfer device is subsequently moved by means of a travel device to the position where the number of labels picked up is to be applied onto the film strip. 
     The pneumatically operated lifting device then transfers the labels to the film strip and presses them on to the film strip, so that the labels remain securely adhered to the film strip. The film strip may be a lower film or a top film, and is hereinafter also referred to as the article strip. A vertical pressing position is adjusted by the duration which the pneumatic lifting device is supplied with compressed air. Additionally, the volume flow and thereby the lifting speed can be adjusted by means of a throttle. 
     The pressing force results from a target position of the lifting device and the position of the film strip onto which the labels are attached. Since the film strips are flexible in the direction of the pressing force, the flexibility together with the deflection of the film strips by the lifting device during the pressing process corresponds to the pressing force. Adjustment of the stroke and the target position, respectively, due to the changing environmental conditions is imprecise and inflexible for differing pack depths, since the volume flow, the duration and pressure applied by the pneumatic lifting device interact. By reducing the volume flow, the target position can be set with a little more accuracy using the duration of the supply of compressed air, but the slower lifting movement reduces the performance of the of the labeler. Fluctuating pressure in the supply line changes the lifting movement or the target position, respectively, without the operator or the machine controls being able to control these conditions. 
     When using spring-loaded pressing elements that press the labels onto the film strip, variations in the lifting movement or the target position, respectively, can be compensated. However, variations or improvements in an initial setting to accommodate for different pack depths does not currently exist. 
     During the movement of the transfer device by means of travel device on a thermo-forming packaging machine, security/safety clearances must be observed as this movement of the transfer device generates high kinetic energy and therefore correspondingly high security/safety clearances are to be observed. These high security/safety clearances require a corresponding high demand in physical space occupied by existing thermo-forming packaging machine of this construction. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a labeling machine enabling precise and easily adjustable target positions at high performance and/or reducing the mechanical load. 
     The labeler according to the invention may comprise a label dispenser, a travel device, a controller and a transfer device for transferring a row of labels dispensed to the transfer device onto an article strip, where the transfer device has lifting device disposed vertically in relation to the article strip. The travel device can comprise a motor and is intended to continuously move the transfer device parallel to the article strip during the transfer of a plurality of rows of labels, and the lifting device comprises a height-adjustable actuator for moving pusher plates. This enables predetermining an exact target position and different pack depths can be adjusted by means of a single parameter via the controller. By transferring the labels onto the article strip with continuous movement of the transfer device along the article strip, the maximum speed of the transfer device and also the accelerations can be reduced while maintaining the same performance of the labeler. This reduces the mechanical loads of the labeler, since the label dispenser and the transfer device possibly have high masses. In one embodiment, the speed of the transfer device is reduced when pressing the labels onto the article strip, but the travel device is not halted, enabling the labeling procedure to run in a steady and continuous manner. 
     The motor of the travel device and the actuator can be movable in an interpolating manner using a controller so that the labeler has to be accelerated less, and to be able to reduce the maximum travel speed, and wherein the performance in applying the labels within a predetermined time can be upheld. Interpolated movability of the motor of the travel device and the actuator of the transmission device, or of the motor of the travel device and the lifting device of the transmission device, means, that the motor and the actuator or the motor and the lifting device, respectively, are controlled by the controller so that the target positions of the motor and the actuator, or the motor and the lifting device, at any given point are respectively computationally offset against one another. Interpolated movablility/movement provides for a continuous overlapped smooth movement of the transfer device in vertical and horizontal directions along the labeling route as illustrated in  FIG. 5   b  . The target value for controlling the motions interfering with one another may be in maintaining a speed as constant as possible and as low as possible when pressing-on the labels. 
     The actuator can be a motor and, in one embodiment, is a stepper motor. Performance of the labeler can be further increased and is independent of external factors such as a compressed air supply in the factory hall. 
     In one embodiment, a lifting force, a lifting speed and/or a lifting height of the lifting device are adjustable by means of parameters via the controller in order to reduce the load on the labeler due to the continuous movement of the transfer device or to increase performance of the labeler due to the simultaneously occurring movement of the transfer device and the lifting device. 
     The transfer device can comprise spring-loaded pusher plates enabling a defined pressing force. 
     The pusher plates may include spring-loaded pusher pins supporting the pressing-on action of labels onto pack bottoms having an uneven surface. 
     Preferably, the transfer device is movable by means of the travel device in a longitudinal or transverse direction relative to the transport direction of the article strip. Furthermore, the labeler can be provided above and/or below the article strip for applying labels from the top and/or the bottom onto the article strip. 
     In one embodiment, the pressing force can be limited by means of the lifting power or the torque of the stepper motor, in order to increase safety for man and machine in case of defect or an incorrectly adjusted machine. 
     The use of a labeler according to the invention on thermoforming packaging machines can occur between a sealing station and a cutting station for applying the labels from above onto the top film and/or from below onto the underside of the pack bottom side of the lower film. 
     In one embodiment, a method according to the invention for multi-track and multi-row application of labels on an article strip comprises the following steps:
         picking up labels from a label dispenser by means of a transfer device,   moving the transfer device in parallel to (i.e. along) the article strip by means of a travel device in or against the direction of transport,   moving the pusher plates by means of a lifting device of the transfer device towards the article strip,   pressing the labels onto the article strip by means of the pusher plates,   moving the pusher plates by means of the lifting device away from the article strip,   wherein the labels are pressed on a package during a continuous movement of the travel device. In this manner, the travel device has more time available for movement of the transfer device at the same performance of the labeler, so that accelerations and speed can be reduced in order to reduce the mechanical load. Continuous movement of the travel device means that the travel device does not interrupt its movement in or against the direction of transport when the labels are pressed on. Consequently, the transfer device maintains a direction component of motion parallel to the article strip due to the travel device while the labels are pressed on, and in particular the component of motion being one of in or against the direction of transport.       

     Moving the transfer device and moving the pusher plates is preferably performed in an interpolating manner 
     A motor, for example a step motor, can be provided for moving the lifting device. 
     In one embodiment, a lifting force, a lifting speed and/or a lifting height of the lifting device can be adjusted via a controller. 
    
    
     
       DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views: 
         FIG. 1  is a top perspective view of a thermo-forming packaging machine with a labeler according to one embodiment of the present invention; 
         FIG. 2  is an enlarged top perspective view of the labeler in a first position according to one embodiment of the present invention; 
         FIG. 3  is an enlarged top perspective view of the labeler of  FIG. 2  in a target position according to one embodiment of the present invention; 
         FIG. 4  is a rear perspective view of a labeler with a lifting drive according to one embodiment of the present invention; 
         FIG. 5   a  is a motion diagram for the movement of the travel device and the lifting movement of the transfer device according to prior art; and 
         FIG. 5   b  is a motion diagram for the movement of the travel device and the lifting movement of the transfer device according to one embodiment of the present invention. 
     
    
    
     Identical components are designated throughout the figures with the same reference numerals. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures. 
     The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
       FIG. 1  shows a section of a thermo-forming packaging machine  1  with a sealing station  2 , into which a lower film  3  and a top film  4  are fed for producing packs  5 . In the sealing station  2 , twelve packs  5  divided into four tracks S and three rows R can be sealed in one work cycle. A labeler  6  according to the invention with a controller  7  is disposed in the transport direction T downstream of the sealing station  2  for applying labels  8  to the twelve packs  5  from above onto the top film  4 . The controller  7  of the labeler  6  can also be integrated into the controller  9  of the thermo-forming packaging machine  1 . The labeler  6  comprises a label dispenser  10 , a travel device  11  and a transfer device  12 . 
       FIG. 2  shows the label dispenser  10  with a carrier strip  13  for labels  8 , where the labels  8  are removed from a dispensing edge  14  of the carrier strip  13  and transferred to the transfer device  12 . The transfer device  12  is for better representation shown without a casing. By means of negative pressure generated by a fan, not shown, the labels  8  are with their non-adhesive top side held on conveyor belts  16 , while a first row R 1  of labels  8  is picked up with the number of tracks S from the transfer device  12 . During this phase, a lifting device  17  of the transfer device  12  is in a pick-up position. In order to apply the row R 1  of labels  8  downwardly onto the top film  4 , the travel device  11  moves the label dispenser  10  with the transfer device  12  in or against the transport direction T to the position in which the row R 1  of labels  8  is applied from above to the top film  4  The drive for the travel device  11  is embodied by a schematically illustrated motor  11   a , for example a servo motor or stepper motor, and a toothed belt drive  11   b . The transfer device  12 , however, can also be positioned above the first row of packs  5 , while the first row R 1  of labels  8  is picked up. 
       FIG. 3  shows the phase in which the lifting device  12  comprising the pusher plates  18  with spring-loaded pins  19  has been moved so far down that the labels  8  were lifted off by the pusher pins  19  from the conveyor belts  16  and the pressed onto the top film  4 . In this, the pusher plates  18  are moved by means of a stepping motor  20  and a belt gear  21  to this target position. This can be adjusted by the operator such that an optimal and pre-defined pressing force is generated by means of the spring-loaded pusher pins  19  for pressing-on the labels  8 . 
       FIG. 4  shows the design of the lifting device  17  in the perspective in the transport direction T. The stepping motor  20  transmits its rotational movement and its torque to a belt  22  which is connected to a base plate  23 . By means of two guide rollers  24  and guides  25  for the base plate  23 , the rotational movement of the stepping motor  20  is converted into a vertical movement of the base plate  23 . The pusher plates  18  are distanced to one another far enough in order to be able to pass between the transport belts  16 , thereby picking up the labels  8  from the conveyor belt  16  and applying them to the top film  4 . In this embodiment shown, the pusher plates  18  comprise pusher pins  19 , which are embodied in a spring-loaded manner in the lifting direction H. 
     The method of the present invention is described as follows. After depositing the first row R 1  of labels  8 , the lifting device  12  again returns to the pick-up position in that the pusher plates  18  are moved vertically upwards in order to pick up a new row R 2  of labels  8  from the dispensing unit  10  in order to then apply them to a neighboring row R 2  of the packs previously provided with labels  5  or to the top film  4 , respectively. For this, the travel device  11  moves the label dispenser  10  with the transfer device  12  in or against the transport direction T to this new position. This process is repeated according to the number of rows R to be labeled in a single work cycle. In order to reduce high accelerations and speeds during the movement of the label dispenser  10  together with the transfer device  12 , and thereby to also increase the lifetime and to reduce the mechanical loads on the labeler  6 , respectively, the labels  8  are deposited and pressed onto the top film  4  when the travel device  11  is activated and thereby a continuous movement of the transfer device  12  is effected. This means, that the label dispenser  10  together with the transfer device  12  is not halted for depositing the labels  8 , but further moved until the work cycle is completed by setting down the last row R 3  of labels  8 . 
     Alternatively or additionally, a respective labeler  6  can also be disposed below the lower film  3  in order to apply labels  8  on the bottom surface of the lower film  3  of the packs  5  in a manner analogous to the method described above. For packs  5  being formed having differing depths, the target position of the lifting device  17  can be entered via a parameter into the controller  7  and be stored in a program. It is also possible to adapt the speeds and accelerations of the travel device  11  and the lifting device  12  such that at maximum power or at a minimum time for a work cycle, respectively, the mechanical load on the labeler  6  can be reduced due to lower accelerations and speeds. Throughout the entire work cycle, the top film  4  and the lower film  3  are at rest. 
       FIG. 5   a  in a graph shows the movement of a transfer device  12  according to prior art having a pneumatically driven lifting device  17  and a motor-driven travel device  11 . The vertical coordinate axis of the graph shows the vertical movement of the lifting device H and the horizontal coordinate axis shows the movement of the travel device  11  in the transport direction T for three rows R 1 , R 2 , R 3  to be labeled. Due to the varying target position which was only inaccurately adjustable, a row of labels  8  could only be deposited when the travel device  11  was stopped at the target positions A, B, C. 
       FIG. 5   b  shows the movements according to the method of one embodiment of the present invention in a diagram with a lifting device  17  comprising a motor drive  20 . Due to the fact that the target position A, B, C for depositing the rows R 1 , R 2 , R 3  of labels  8  is exactly approachable, the movement of the transfer device  12  from one row to the next does not need to be interrupted or stopped while the labels are deposited  8 . In the section D or E, respectively, of the travel route of the transfer device  12 , new labels are picked up from the label dispenser  10  for the following rows R 2  or R 3 , respectively. 
     During the same time interval between two depositing processes, the speed of the movement between the rows and the movement during the depositing process can be reduced in order to subsequently increase the speed again. This adjustment results in less acceleration and a reduced maximum speed during the movement of the label dispenser  10 , and the transfer device  12 . With three rows to be labeled R 1 , R 2 , R 3 , this is evident only for the center row R 2 , since the transfer device  12  is at the beginning of the work cycle already positioned at the first or the last row. It is likewise conceivable that the speed of the transfer device  12  across the travel distance from A to C is constant and corresponds to the time that is determined as being available to the packaging machine for the labeling process. 
     From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting. 
     The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.