Abstract:
A method and unit for applying a label to an article, whereby a supporting head is fed by a conveyor along a labelling path; the label is fed to a first seat of the supporting head; the article is fed to a second seat of the supporting head; and a relative movement is produced between the first seat and the second seat of the supporting head to apply the label to the article.

Description:
[0001]     The present invention relates to a method and unit for applying a label to an article.  
         [0002]     The present invention is particularly advantageous for use on a cigarette packing machine, for applying revenue labels to packets of cigarettes, to which the following description refers purely by way of example.  
         [0003]     In many countries, a non-removable revenue label must be applied to the outer surface of a packet of cigarettes in such a position as to be torn when the packet is unsealed, and serves to demonstrate payment of tobacco retail taxes.  
       BACKGROUND OF THE INVENTION  
       [0004]     Various types of units for applying revenue labels to packets of cigarettes on a cigarette packing machine are known, some of which are described in patents U.S. Pat. No. 5,203,953 A1, EP1125843A1, DE19730307A1, U.S. Pat. No. 5,607,526 A1, U.S. Pat. No. 5,111,633 A1, and GB2103584A.  
         [0005]     U.S. Pat. No. 4,655,871 A1 describes a unit for supplying revenue labels on a cigarette packing machine, in which each packet coming off a packing assembly is fed along an unloading path extending through a fork-type gripper; between two arms of the gripper is stretched a revenue label removed beforehand by the gripper from a respective pocket integral with the periphery of a roller tangent to a conveyor roller, which has projections for retaining and feeding a revenue label to the relative pocket along a path tangent to a gumming roller.  
         [0006]     EP662423A1 describes a unit for applying revenue labels to packets of cigarettes bounded by two parallel faces connected by a further face; and the unit comprises a conveyor for feeding the packets to a labelling station, and a label feeder having at least one device for retaining two opposite end portions of a label. The conveyor feeds the packets successively, with the further face downstream with respect to the travelling direction of the conveyor; and an actuator is provided to move the label-retaining device between a position interfering with the path of each packet at the labelling station, and a position of non-interference with the path.  
         [0007]     U.S. Pat. No. 6,763,870 B1 describes a unit for applying revenue labels to packets of cigarettes travelling in a feed direction along a first path; a gripping head is fed along a second path; and each label is applied to a first face of a respective packet by inserting the gripping head between a packet and the adjacent downstream packet, and rolling the gripping head to apply the label along the first face, which is perpendicular to the feed direction.  
         [0008]     U.S. Pat. No. 5,309,695 A1 describes a unit for applying adhesive revenue labels to packets of cigarettes. The unit comprises an endless conveyor for feeding labels along a path having a first portion extending along a portion of a packet feed path, a second portion extending from the output of the first portion to a loading station for loading the labels onto the conveyor, and a third portion extending from the loading station to the input of the first portion and through a gumming device. The conveyor is a suction conveyor, and comprises a first suction chamber, in which a vacuum is maintained selectively and which extends along the first and second portion of the label path; and a second suction chamber, in which a vacuum is maintained constantly and which extends along the third portion of the path.  
         [0009]     Patent Application ITBO200300047A describes a device for applying a revenue label to a packet of cigarettes travelling along a conveying path. To apply the label to the packet, a gripping head is fed along a feed path by rotating the gripping head about two parallel axes, and by moving the gripping head radially with respect to one of the two axes.  
         [0010]     U.S. Pat. No. 5,111,633 A1 describes a unit for applying revenue labels to packets of cigarettes, and which comprises a device for feeding the packets to a labelling station; and a label feeder, in turn comprising a rotary conveyor substantially tangent to the labelling station and having suction retaining means for retaining individual labels on the cylindrical surface of the rotary conveyor. Each retaining means has a folding member movable substantially radially with respect to the rotary conveyor; and actuating means for activating the folding member, and which operate between a withdrawn position with respect to the rotary conveyor, and an extracted work position at the labelling station.  
         [0011]     Known units for applying revenue labels to packets of cigarettes are relatively cheap and easy to produce, but only perform satisfactorily at low operating speeds (roughly 400-500 applications a minute), i.e. fail to provide for precise application of revenue labels to packets of cigarettes at high operating speeds. To overcome this drawback, new types of units for applying revenue labels have been proposed, but have proved complex and expensive, while still failing to ensure good performance at very high operating speeds (roughly 700-800 applications a minute).  
       SUMMARY OF THE INVENTION  
       [0012]     It is an object of the present invention to provide a method and unit for applying a label to an article, designed to eliminate the aforementioned drawbacks, and which, in particular, are cheap and easy to implement.  
         [0013]     According to the present invention, there are provided a method and unit for applying a label to an article, as recited in the attached Claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0015]      FIG. 1  shows a schematic front view, with parts removed for clarity, of a unit for applying revenue labels to soft packets of cigarettes, and in accordance with the present invention;  
         [0016]      FIG. 2  shows a view in perspective of a packet of cigarettes featuring a revenue label;  
         [0017]     FIGS.  3  to  5  show larger-scale views in perspective, with parts removed for clarity, of a detail of the  FIG. 1  unit in different operating positions;  
         [0018]      FIG. 6  shows a larger-scale view in perspective, with parts removed for clarity, of an actuating device of the  FIG. 1  unit. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Number  1  in  FIG. 1  indicates as a whole a labelling unit for applying revenue labels  2  to soft packets  3  of cigarettes on a packing machine (not shown).  
         [0020]     As shown in  FIG. 2 , each packet  3  of cigarettes contains an orderly group (not shown) of cigarettes, is parallelepiped-shaped, and is defined by a lateral surface, and by two opposite, identical, flat, respectively top and bottom end walls  4  and  5  parallel to each other and bounding the lateral surface. The lateral surface comprises two opposite, flat, parallel minor lateral walls  6 , and two opposite, flat major lateral walls  7  crosswise to minor lateral walls  6 . Each revenue label  2  is in the form of an elongated rectangle, and is folded into a “U” onto top end wall  4  and major lateral walls  7  of a respective packet  3  of cigarettes.  
         [0021]     As shown in  FIG. 1 , labelling unit  1  comprises a wheel  8  rotating continuously about a respective central axis  9  perpendicular to the  FIG. 1  plane, and supporting a number of supporting heads  10 . Supporting heads  10  are equally spaced about axis  9 , are fed, by rotation of wheel  8 , along a circular labelling path P 1 , and each comprise a seat  11  for receiving a respective label  2 , and a seat  12  for receiving a respective packet  3  of cigarettes.  
         [0022]     As shown in  FIG. 6 , each seat  11  comprises a suction surface  13  for receiving and retaining a respective label  2 , and which has a slight circular curve. Each seat  11  is fitted movable to supporting head  10  to rotate, with respect to supporting head  10  and under the control of an actuating device  14 , about an axis  15  slanting with respect to suction surface  13  of seat  11 . More specifically, each actuating device  14  comprises a shaft  16  fitted to wheel  8  to rotate about a respective axis  15 , and an outer end of which supports seat  11 . An inner end of shaft  16  is integral with a gear  17  meshing with a rack  18 , which slopes with respect to gear  17  and is moved by a cam system (not shown) to produce a relative movement between rack  18  and gear  17 . Preferably, suction surface  13  of each seat  11  is movable with respect to shaft  16  in a direction perpendicular to suction surface  13  and in opposition to an elastic member (not shown).  
         [0023]     As shown in  FIGS. 1 and 3 , each seat  12  is fitted in a fixed position to supporting head  10 , i.e. performs no movement with respect to supporting head  10  as supporting head  10  travels along labelling path P 1 , and comprises a fixed seating body  19  for engaging a major lateral wall  7  of packet  3 , and two movable grippers  20  for engaging end walls  4  and  5  of packet  3 . More specifically, each seating body  19  comprises two U-shaped supporting members  21  for engaging both a major lateral wall  7  of a packet  3 , and a small portion of minor lateral walls  6  of a packet  3 . In an alternative embodiment not shown, each seating body  19  may be hinged to wheel  8  to oscillate, under the control of a cam system, about an axis parallel to the rotation axis  9  of wheel  8  to assist loading and unloading of packet  3 . Movable grippers  20  are fitted to supporting head  10  to rotate about respective axes sloping with respect to each other. In a preferred embodiment, movable grippers  20  are both fitted rigidly to a pin  22 , rotating about an axis parallel to the rotation axis  9  of wheel  8 , with the interposition of respective supporting bodies  23  sloping with respect to each other and with respect to the rotation axis of pin  22 . One gripper  20  has a rectangular opening  24  to permit application of a revenue label  2  to top end wall  4  while top end wall  4  is engaged by gripper  20 .  
         [0024]     Each supporting head  10  also comprises a U-shaped folding member  25  fitted to supporting head  10  to move linearly in a direction parallel to the rotation axis  9  of wheel  8  and therefore perpendicular to labelling path P 1 . To allow passage of U-shaped folding member  25 , each seat  11  has two through holes  26 , which come out at suction surface  13 . Each seat  11  preferably comprises a control member (not shown in detail) for cutting off suction through suction surface  13  of seat  11 , and which is activated by passage of U-shaped folding member  25  through the through holes  26  in seat  11 .  
         [0025]     As shown in  FIG. 1 , labelling unit  1  comprises a feed device  27  for feeding revenue labels  2  successively to seats  11  at a feed station S 1  located along labelling path P 1 . Feed device  27  comprises a wheel  28  rotating continuously about a respective central axis  29  parallel to rotation axis  9  of wheel  8 ; rotating wheel  28  supports a number of suction gripping heads  30 , and feeds gripping heads  30  along a feed path P 2 ; and each suction gripping head  30  is hinged to wheel  28  to oscillate, under the control of a cam system (not shown), about an axis parallel to the rotation axis  29  of wheel  28 . Feed device  27  also comprises a pickup station S 2  having a store  31  containing a stack  32  of labels; and a pickup station S 3  having a cutting unit  33  (e.g. of the type described in U.S. Pat. No. 4,675,069-A1) for cutting a revenue label  2  off a continuous strip  34  of labels unwound off a reel (not shown). It should be pointed out that pickup stations S 2  and S 3  are used alternatively, i.e. a gripping head  30  removes a revenue label  2  from pickup station S 2  or pickup station S 3 .  
         [0026]     Along labelling path P 1  and upstream from feed station S 1 , labelling unit  1  comprises a gumming station S 4  for gumming an inner surface of each revenue label  2  as revenue label  2  is advanced by seat  11  of a respective supporting head  10 .  
         [0027]     Finally, labelling unit  1  comprises a feed station S 5  located upstream from feed station S 1  along labelling path P 1 ; and a release station S 6  located upstream from feed station S 5  along labelling path P 1 .  
         [0028]     At feed station S 5 , packets  3  of cigarettes are fed to respective seats  12  of supporting heads  10  by a number of seats  35  fed by a packing conveyor (not shown in detail) along a packing path P 3  tangent to labelling path P 1  at feed station S 5 .  
         [0029]     At release station S 6 , packets  3  of cigarettes, complete with respective revenue labels  2 , are released from seats  12  of supporting heads  10  to seats  36  fed by a transfer conveyor  37  along a transfer path P 4  partly coincident with labelling path P 1  at release station S 6 . Transfer conveyor  37  comprises an endless flexible support (typically a chain) looped about at least two end pulleys  39  (only one shown in  FIG. 1 ). The end pulley  39  shown in  FIG. 1  is coaxial with rotation axis  9  of wheel  8 , and rotates synchronously with wheel  8 . Transfer conveyor  37  also comprises a number of pairs of deformable bodies  40  connected to flexible support  38 , and each pair of which are spaced apart to define a respective seat  36 , and engage two opposite minor lateral walls  6  of a corresponding packet  3  of cigarettes to grip packet  3  of cigarettes between them.  
         [0030]     Each deformable body  40  comprises a rigid jaw  41  having one end  42  for retaining packet  3  of cigarettes, and an end  43  opposite end  42 . End  42  of each jaw  41  is connected to flexible support  38  by a connecting member  44  hinged to both jaw  41  and flexible support  38 , while end  43  of each jaw  41  is connected to flexible support  38  by a connecting member  45  hinged to jaw  41  and fixed rigidly to flexible support  38 . Jaws  41  are preferably arranged so that ends  43  of each two adjacent jaws  41  are superimposed, and the superimposed ends  43  of each two adjacent jaws  41  are both hinged to the same connecting member  45 .  
         [0031]     It is important to note that jaws  41  of transfer conveyor  37  are entirely passive, i.e. no actuating devices are provided to produce any movement between jaws  41  and flexible support  38 . Given the way in which jaws  41  are connected to flexible support  38 , each jaw  41  tends to oscillate with respect to end  43  when flexible support  38  assumes a curved configuration, thus opening seats  36 , i.e. spreading jaws  41  defining each seat  36 , when flexible support  38  assumes a curved configuration, and subsequently closing seats  36 , i.e. bringing closer together jaws  41  defining each seat  36 , when flexible support  38  assumes a straight configuration.  
         [0032]     Operation of labelling unit  1  will now be described with reference to one packet  3  of cigarettes and a corresponding revenue label  2 .  
         [0033]     Label  2  is picked up by a gripping head  30  from the bottom of stack  32  in store  31  or from strip  34  at cutting unit  33 , and is then transferred in known manner by gripping head  30  to seat  11  of a supporting head  10  at feed station S 1 . On receiving label  2 , supporting head  10  continues along feed path P 1  through gumming station S 4 , where an inner surface of label  2  is gummed in known manner.  
         [0034]     At feed station S 5 , packet  3  of cigarettes is fed from a seat  35  to seat  12  of supporting head  10 , by moving packet  3  with respect to both seat  35  and seat  12 , and in a direction perpendicular to both packing path P 3  and labelling path P 1 .  
         [0035]     Up to feed station S 5 , seat  11  of supporting head  10  is maintained stationary with respect to supporting head  10  and seat  12 . More specifically, seat  11  is maintained in such a position as to receive label  2  with suction surface  13  perpendicular to and alongside end walls  4  and  5  of packet  3 . Once through feed station S 5 , seat  12  remains stationary with respect to supporting head  10 , and seat  11  is moved with respect to seat  12  and supporting head  10  to apply label  2  to packet  3  of cigarettes under the control of actuating device  14 . As stated, seat  11  is moved with respect to seat  12  and supporting head  10  by rotating about axis  15 , which slants with respect to suction surface  13  of seat  11 . More specifically, rotation of seat  11  about axis  15  positions suction surface  13  of seat  11  facing top end wall  4  of packet  3  of cigarettes, to apply label  2  to top end wall  4 . Label  2  is then folded into a “U” onto major lateral walls  7  of packet  3  of cigarettes by U-shaped folding member  25  moving through holes  26  in seat  11 . As stated, when inserted through holes  26  in seat  11 , U-shaped folding member  25  activates a control member (not shown) to cut off suction through suction surface  13  of seat  11 .  
         [0036]     Finally, at release station S 6 , packet  3  of cigarettes, complete with label  2 , is released from seat  12  of supporting head  10  to a seat  36  on transfer conveyor  37 . More specifically, when fed from seat  12  to seat  36 , packet  3  is maintained stationary with respect to both seat  12  and seat  36 , and transfer is possible by transfer path P 4  being partly coincident with labelling path P 1 , so that seat  36  can engage packet  3  of cigarettes while packet  3  of cigarettes is still engaged by seat  12 .  
         [0037]     Labelling unit  1  as described above has numerous advantages: it is compact, is cheap and easy to produce, and operates accurately at high operating speed. Precision labelling is particularly ensured by seat  11 , for receiving a revenue label  2 , and seat  12 , for receiving a corresponding packet  3  of cigarettes, being conveyed together by the same supporting head  10 , so that an extremely precise position of seat  11  with respect to seat  12  is guaranteed at all times, regardless of the travelling speed of supporting head  10 .  
         [0038]     In view of its numerous advantages, labelling unit  1  as described above may also be used to advantage on other automatic machines for packing products other than cigarettes, or on other than automatic packing machines, for applying a label of any type to the outer surface of an article. For example, labelling unit  1  as described above may be used to apply labels to bottles or packages of food products.