Abstract:
A method and unit for applying labels to packets of cigarettes, traveling in a given direction along a first path with a given spacing and arranged a given distance apart, provide for feeding a gripping head along a second path, and applying each label to a first face of a respective packet by inserting the gripping head between one packet and the adjacent following packet to roll the gripping head and apply the label along the first face, which is perpendicular to the given direction.

Description:
[0001]    The present invention relates to a method of applying labels.  
           [0002]    More specifically, the present invention relates to a method of applying labels to packets of cigarettes, to which the following description refers purely by way of example.  
         BACKGROUND OF THE INVENTION  
         [0003]    Known methods of applying labels to packets of cigarettes comprise feeding the packets of cigarettes in a given direction along a first path; withdrawing the labels by means of a gripping head from the outlet of a store; feeding the gripping head and relative label along a given second path; and applying each label to a respective packet, on a face parallel to the traveling direction of the packet.  
           [0004]    When the label is also folded onto further faces of the packet, units implementing the above methods require a movable folding device for each free portion of the label; and the above methods must also ensure each packet and the gripping head by which the label is applied to the packet are fed at the same speed along parallel portions of the respective paths to prevent relative slippage of the packet and label and so ensure precise application of the label.  
           [0005]    Controlling the two feed speeds, however, is extremely difficult, particularly when a high degree of precision is required.  
           [0006]    The accuracy with which the label is applied is extremely important in the case of revenue stamps applied to hinged-lid packets of cigarettes and having tear lines.  
           [0007]    Hinged-lid packets of cigarettes comprise a cup-shaped body and a lid separated from the cup-shaped body by a parting line; and labels with tear lines must be applied extremely accurately so that the tear line corresponds to the parting line. Otherwise, the tear line remains intact, and therefore serves no purpose, when the packet is unsealed.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide a method of applying labels, designed to eliminate the drawbacks of known methods.  
           [0009]    According to the present invention, there is provided a method of applying labels to packets, in particular packets of cigarettes, traveling in a given direction along a first path with a given spacing and arranged a given distance apart; the method comprising feeding a gripping head along a second path, and applying a said label to a first face of said packet; and the method being characterized by inserting said gripping head between one packet and the adjacent following packet to apply said label along said first face; said first face being perpendicular to said given direction.  
           [0010]    The present invention also relates to a unit for applying labels.  
           [0011]    According to the present invention, there is provided a unit for applying labels to packets, in particular packets of cigarettes, traveling in a given direction along a first path with a given spacing and arranged a given distance apart; the packets having respective first faces perpendicular to said given direction; the unit comprising at least one gripping head movable along a second path to apply a said label to a respective packet; and the unit being characterized by comprising at least one movable arm for inserting said gripping head between one packet and the adjacent following packet to apply said label along said first face. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0013]    [0013]FIG. 1 shows a plan view, with parts removed for clarity, of a unit for applying labels in accordance with the present invention;  
         [0014]    [0014]FIG. 2 shows a view in perspective of a packet bearing a label applied using the method according to the present invention;  
         [0015]    FIGS.  3  to  5  show plan views, with parts removed for clarity, of details of the FIG. 1 unit at successive steps in the method according to the present invention;  
         [0016]    [0016]FIG. 6 shows a section of a detail of the FIG. 1 unit along line VI-VI. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    Number  1  in FIG. 1 indicates as a whole a unit for applying labels  2  to packets  3  of cigarettes traveling continuously along a path P 1  extending in a direction D 1 .  
         [0018]    As shown more clearly in FIG. 2, packets  3  are rigid hinged-lid types. Each packet  3  comprises a cup-shaped body  4  and a lid  5 , and, once label  2  is applied, has a label  2  applied partly to lid  5  and partly to cup-shaped body  4 . When lid  5  is in the closed position, packet  3  has a front face  6 , a rear face  7 , a bottom face  8 , a top face  9 , and two lateral faces  10  and  11 . Lid  5  and cup-shaped body  4  are hinged along rear face  7  and are separated by a parting line  12  along front face  6  and by two parting lines  13  along respective lateral faces  10  and  11 . Label  2  has a central portion  14  adhering to top face  9 ; an end portion  15  adhering to lateral face  10 ; and an end portion  16  adhering to lateral face  11 . Central portion  14  and portion  16  adhere solely to lid  5 , whereas portion  15  adheres partly to lid  5  and partly to cup-shaped body  4 . Portion  15  is in turn divided into two parts  17  and  18  by a tear line  19  extending along parting line  13  along wall  10 .  
         [0019]    With reference to FIG. 1, unit  1  comprises a transfer wheel  20 ; a store  21  of labels  2 ; a conveyor  22  for packets  3 ; a cutting device  23 ; and a gumming device  24 .  
         [0020]    Store  21  comprises guides  25  for maintaining labels  2  in a pack and for guiding each label  2  to an outlet of store  21  in a given pickup position in which label  2  lies and is maintained by two teeth of guides  25  in a vertical plane.  
         [0021]    The store comprises a pusher S for feeding the pack of labels  2  towards the outlet.  
         [0022]    Conveyor  22  comprises a support  26 , shown by the dash lines in FIG. 1, on which packets  3  are equally spaced with top faces  9  perpendicular to direction D 1  and front faces  6  facing support  26 . Along path P 1  of conveyor  22 , two fixed folding devices  27  and  28  are provided on opposite sides of conveyor  22  so as to contact respective lateral faces  10  and  11  of each packet  3 .  
         [0023]    Wheel  20  comprises a central hub  29  rotating continuously clockwise, in FIG. 1, about a respective vertical axis  30 ; and a number of arms  31  rotating, with respect to hub  29 , about respective axes  32  parallel to and equally spaced about axis  30 . Each arm  31  is fitted on the end with a gripping head  33 , which rotates about an axis  34  parallel to axis  30  and is fed along a path P 2 .  
         [0024]    With reference to FIG. 6, each arm  31  comprises a hollow body  35  integral with a sleeve  36 , which rotates about axis  32  and is integral with a lever  37  having a roller  38  which engages a cam (not shown) to position arm  31  according to the angular position assumed by axis  32  of respective arm  31  about axis  30 .  
         [0025]    Gripping head  33  has a gripping wall  39  in the form of a cylindrical sector extending about axis  34 , and which has a number of suction holes  40  for retaining label  2  on gripping wall  39 . Gripping head  33  is integral with a shaft  41  mounted for rotation about axis  34  and in turn integral with a pulley  42 . Sleeve  36  is fitted inside with a shaft  43 , which rotates about axis  32  and is fitted, on the top end, with a pulley  44  larger in diameter than pulley  42 , and, on the bottom end, with a rocker arm  45  having two rollers  46  which engage respective cams (not shown) for rotating pulley  44  about axis  32  according to the angular position assumed by axis  32  about axis  30 . A belt  47  is looped about pulleys  44  and  42  to transmit rotation from pulley  44  to pulley  42 ; and a suction channel  48  is formed inside hub  29 , sleeve  36 , hollow body  35 , shaft  41  and gripping head  33  to selectively activate suction holes  40 .  
         [0026]    With reference to FIG. 1, cutting device  23  comprises a supporting member  49  supporting a blade  50  in a fixed position with respect to path P 2 ; and gumming device  24  comprises a gumming spray nozzle  51  also in a fixed position along path P 2 .  
         [0027]    In actual use, unit  1  for applying labels  2  feeds packets  3  along path P 1  in direction D 1 , with top faces  9  perpendicular to and at the front with respect to traveling direction D 1 , and with packets  3  equally spaced along support  26  with a given spacing P and a gap I between each packet  3  and the adjacent following packet  3 .  
         [0028]    Hub  29  is rotated continuously about axis  30 , arms  31  are oriented about axes  32  according to the angular position assumed by axes  32  about axis  30 , and gripping heads  33  are rotated about axes  34  also according to the angular position assumed by axes  32  about axis  30 . Each gripping head  33  is fed along endless path P 2 , which intersects path P 1  at two points A and B; and, along path P 2 , each gripping head  33  travels past store  21 , cutting device  23  and gumming device  24 .  
         [0029]    As gripping head  33  nears store  21 , arm  31  is rotated clockwise about axis  32  so that gripping wall  39  contacts the label  2  in the pickup position inside store  21 .  
         [0030]    Once wall  39  contacts label  2 , arm  31  is rotated anticlockwise in FIG. 1, so that the combined rotations about axis  30  and axis  32  arrest gripping head  33  at the point of contact between wall  39  and label  2 . And, while gripping head  33  is stationary, suction holes  40  are activated, and gripping head  33  then moved along a straight portion T 1  of path P 2 .  
         [0031]    As shown more clearly in FIG. 3, along portion T 1 , the suction through holes  40  is maintained, and gripping head  33  is rotated about axis  34  by rocker arm  45  and the mechanical transmission defined by pulleys  42  and  44  and belt  47 , which transmits rotation to gripping head  33 . As gripping head  33  rotates about axis  34  and is moved along straight portion T 1 , gripping wall  39  rolls along label  2 , which, by virtue of the suction through holes  40 , adheres to gripping wall  39  and is gradually withdrawn from the outlet of store  21 .  
         [0032]    Gripping head  33  is then fed, together with label  2 , along a straight portion T 2  of path P 2  past cutting device  23 , as shown more clearly in FIG. 4, and is rotated about axis  34  so that label  2  contacts fixed blade  50  to form tear line  19 .  
         [0033]    With reference to FIG. 1, at gumming device  24 , arm  31  is first rotated clockwise in FIG. 1 and then anticlockwise to form a pointed portion T 3  of path P 2 ; and gripping head  33  is rotated about axis  34  along portion T 3  to position the whole surface of label  2  in front of nozzle  51  which gums label  2 .  
         [0034]    Gripping head  33  is then fed along a portion T 4 , along which gripping head  33  is positioned inside the gap I between one packet  3  and the adjacent following packet  3 , and wall  39  is brought into contact with and rolled along top face  9  of the following packet  3 . In other words, with reference to FIG. 5, gripping head  33  and respective label  2  are brought into a position of interference with respect to a packet  3  traveling in direction D 1 , and in which label  2  is brought into contact with top face  9  of packet  3 . At this stage, suction holes  40  are deactivated, and wall  39  rolls along top face  9  to lay label  2  gradually on top face  9 .  
         [0035]    Portion  15  projects with respect to lateral face  10  and is folded onto face  10  by fixed folding device  27 . In the meantime, gripping head  33  lays the whole of central portion  14  of label  2  on top face  9  so that portion  16  projects with respect to lateral face  11 ; and gripping head  33  is then fed along path P 2  between fixed folding devices  27  and  28 , and packet  3  is brought into contact with fixed folding device  28  to fold portion  16  onto lateral face  11 .  
         [0036]    The present invention is particularly advantageous by preventing relative slippage of the packet and label as the label is applied, thus ensuring a high degree of precision; by enabling the free portions to be folded by fixed folding devices; and by the highly maneuverable gripping head greatly simplifying the cutting and gumming devices.