Abstract:
A method of producing hinged-lid packets of cigarettes on a continuous automatic machine, whereby a blank is closed about a group of cigarettes, the blank having a longitudinal axis, a rear panel, first tabs connected to the rear panel, and second and third tabs connected to the first tabs; the method providing for feeding the blank continuously along a given path with the axis of the blank crosswise to the path; and folding the first tabs with respect to the rear panel so that the second and third tabs are so positioned as to be intercepted by fixed folding devices located along the path.

Description:
[0001]    The present invention relates to a method of producing hinged-lid packets of cigarettes.  
         BACKGROUND OF THE INVENTION  
         [0002]    Hinged-lid packets of cigarettes are normally produced on automatic machines comprising step conveyors and implementing various methods, all of which are based on two opposite principles: a first, whereby a group of cigarettes and a flat blank are brought together, and the blank is folded about the group of cigarettes to enclose the group inside the blank; and a second, whereby the blank is folded to form a pocket, the group is inserted into the pocket, and further folds are made to enclose the group of cigarettes inside the blank.  
           [0003]    Methods based on the second principle have been widely used in the past, and have the advantage of speeding up the production of packets of cigarettes by permitting parallel performance of separate operations on the blanks and groups before the two are brought together, so that relatively few folds remain to be made once the groups of cigarettes are inserted inside the blanks. Methods based on the second principle, however, call for inserting the group extremely accurately inside the pocket, to avoid damaging the group and/or blank, and, for this reason, have proved unsuitable for use on continuous automatic machines, on which the extremely high speed at which the groups and blanks are brought together does not allow the group and the pocket to be maintained facing each other long enough to ensure correct insertion of the group inside the pocket of the blank.  
           [0004]    Methods based on the first principle are undoubtedly more suitable for use on continuous automatic machines, in that any inaccuracy when the group and blank are brought together produces no damage to either, and can be corrected later when folding the blank by means of folding devices. Nevertheless, such methods, when used on continuous automatic machines, also involve drawbacks, by requiring that the machines be equipped with a large number of movable folding devices, which complicate the machine and only operate once the groups of cigarettes and blanks have been brought together.  
           [0005]    DE-3536791 discloses an automatic packing machine for the continuous production and filling of hinge-lid packs. In the machine disclosed by DE-3536791, blanks are fed from a plurality of magazines via a continuously running feeder conveyor to a likewise continuously rotating folding conveyor; the already prefolded blanks are introduced directly by the feeder wheel into pockets of a pocket chain and during transport of such pockets, prefabricated cigarette blocks are conveyed to the pockets and the blanks in these by diagonal conveyors; finally, the largely ready-folded hinge-lid packs are ejected from the pockets by accompanying conveyors in the same way.  
           [0006]    DE-3536791 discloses a continues packing machine, which partially folds a blank before feeding the relevant cigarette block to such blank; however, the machine disclosed by DE-3536791 results relatively complicated and bulky and, thus, expensive.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the present invention to provide a method of producing hinged-lid packets of cigarettes, designed to eliminate the drawbacks of the known state of the art, and which, in particular, is suitable for use on a continuous automatic machine.  
           [0008]    According to the present invention, there is provided a method of producing hinged-lid packets of cigarettes as recited by claim 1.  
           [0009]    The present invention relates to a machine for producing hinged-lid packets of cigarettes.  
           [0010]    According to the present invention, there is provided a machine for producing hinged-lid packets of cigarettes as recited by claim 11.  
           [0011]    The present invention also relates to a method of producing hinged-lid packets of cigarettes.  
           [0012]    According to the present invention, there is provided a method of producing hinged-lid packets of cigarettes as recited by claim 19. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    A non-limiting embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0014]    [0014]FIG. 1 shows a view in perspective of a packet of cigarettes produced using the method according to the present invention;  
         [0015]    [0015]FIG. 2 shows a plan view of a flat blank which may be used to form the FIG. 1 packet;  
         [0016]    [0016]FIG. 3 shows a side view, with parts removed for clarity, of a machine for producing packets of cigarettes using the method according to the present invention;  
         [0017]    [0017]FIGS. 4 a - 4   d  show plan views of the FIG. 2 blank folded partly at successive steps in the method according to the present invention;  
         [0018]    [0018]FIGS. 5 a - 5   d  show front views of the FIG. 2 blank folded partly at successive steps in the method according to the present invention;  
         [0019]    [0019]FIG. 6 shows a plan view of a blank folded partly according to a variation of the method according to the present invention;  
         [0020]    [0020]FIG. 7 shows a front view of the FIG. 6 blank. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Number  1  in FIG. 1 indicates a hinged-lid packet in the form of a parallelepiped and having a longitudinal axis A. Packet  1  comprises a cup-shaped body  2 ; a hinged lid  3  tiltable with respect to cup-shaped body  2 ; and a group  4  housed inside cup-shaped body  2 . Group  4  is defined by a given number of cigarettes (not shown in FIG. 1) wrapped in a sheet  5 ; and by a collar  6  contacting sheet  5  and projecting partly with respect to cup-shaped body  2 . Group  4  is substantially of the same parallelepiped shape as packet  1 , and has a longitudinal axis  7  coincident with axis A of packet  1 .  
         [0022]    With reference to FIG. 2, packet  1  is formed from an elongated cardboard blank  8  having a longitudinal axis of symmetry B. Blank  8  comprises a central portion  9  and two lateral portions  10  substantially parallel to axis B. Portion  9  comprises, in succession, a front panel  11 ; a bottom panel  12 ; a rear panel  13 ; a top panel  14 ; a front panel  15  of lid  3 ; and a flap  16 . Panels  11  to  15  and flap  16  are separated from each other by respective preformed bend lines  17 - 21  crosswise with respect to axis B; and rear panel  13  has a further bend line  22  crosswise with respect to axis B and which acts as a hinge between lid  3  and cup-shaped body  2  once blank  8  is folded to form packet  1 .  
         [0023]    Each portion  10  comprises a tab  23  connected to panel  11  by a bend line  24  parallel to axis B; two tabs  25  and  26  connected to panel  13  by a bend line  27  parallel to axis B; and a tab  28  connected to panel  15  by a bend line  29  parallel to axis B. Each tab  25  is integral with a tab  30 , which is located between tabs  23  and  25  and connected to tab  25  by a bend line  31  perpendicular to axis B. Each tab  26  is integral with a tab  32 , which is located between tabs  26  and  28  and connected to tab  26  by a bend line  33  perpendicular to axis B. In actual use, to form packet  1  in FIG. 1, each panel  11 - 15 , flap  16 , and each tab  23 ,  25 ,  26 ,  28 ,  30  and  32  must be folded about adjacent bend lines  17 - 21 ,  24 ,  27 ,  29 ,  31  and  33 , making a total of fifteen folds, which are made on an automatic machine  34  shown partly in FIG. 3. Machine  34  comprises a frame  35 , which supports a packaging wheel  36  rotating about an axis  37 ; a wheel  38  for supplying blanks  8  to wheel  36  and rotating about an axis  39  parallel to axis  37 ; and a packaging wheel  40  rotating about an axis  41  parallel to axis  37 , and which, after folding sheet  5  and positioning collar  6 , feeds groups  4  to wheel  36 . Machine  34  also comprises a spray gumming device  42 , and two helical folding devices  43 , only one of which is shown in FIG. 3. Wheel  36  comprises a disk  44 ; and a number of pockets  45  equally spaced about axis  37  and movable along an annular path P 1  about axis  37 . Each pocket  45  can be oriented, with respect to disk  44 , about a respective axis  46  parallel to axis  37 , and comprises a bottom wall  47 , and two lateral walls  48  hinged to and movable with respect to bottom wall  47  about respective axes  48   a  parallel to axis  37 . Pocket  45  is oriented and lateral walls  48  positioned, for example, by means of respective known cam and tappet mechanisms not shown.  
         [0024]    Wheel  38  comprises a disk  49 ; and a number of gripping heads  50  equally spaced about axis  39  and movable along a respective annular path P 2  extending about axis  39 . Each gripping head  50  can be oriented, with respect to disk  49 , about a respective axis  51  by means of a known mechanism not shown, e.g. a cam and tappet mechanism, and comprises a gripping face  52  on which a blank  8  is retained by suction.  
         [0025]    Like wheels  36  and  38 , wheel  40  comprises a disk  53 ; and a number of pockets  54  equally spaced about axis  41  and movable along a respective annular path P 3  extending about axis  41 . Each pocket  54  can be oriented, with respect to disk  53 , about a respective axis  55  by means of a known mechanism not shown, e.g. a cam and tappet mechanism, and comprises a bottom wall  56 , and two lateral walls  57  perpendicular to bottom wall  56 .  
         [0026]    Pockets  45  and  54  and heads  50  are sized to convey blanks  8  and groups  4  with respective axes B and  7  parallel to axes  37 ,  39  and  41  of respective wheels  36 ,  38  and  40 . More specifically, face  52  of each head  50  is substantially the same size as central portion  9  of blank  8 , and is substantially larger parallel to than crosswise to axis  39 ; each pocket  45  is so sized that bottom wall  47  acts as a support for central portion  9  of blank  8 , and lateral walls  48  face tabs  25  and  26  of blank  8 ; and pocket  54  is so sized as to position group  4  with a major face of group  4  contacting bottom wall  56 , and with the elongated lateral faces of group  4  contacting lateral walls  57 .  
         [0027]    Machine  34  comprises a transfer station  58  for transferring blanks  8  from wheel  38  to wheel  36 ; and a transfer station  59  for transferring groups  4  from wheel  40  to wheel  36 . With reference to path P 1 , station  59  is located downstream from station  58 , which is offset angularly by about 90° with respect to station  59 . Gumming device  42  is located between stations  58  and  59 , and comprises a number of nozzles  60  extending parallel to axis  37  and facing a portion of path P 1  between stations  58  and  59 .  
         [0028]    Helical folding devices  43  are located immediately downstream from station  58 , and (though cut off in FIG. 3 for the sake of clarity) extend parallel to path P 1  to a point beyond station  59 . Each helical folding device  43  comprises a strip  61 , which is initially parallel to axis  37  and twists so as to be eventually perpendicular to axis  37  before reaching station  59 . The two helical folding devices  43  are supported by frame  35 , and are separated by a distance substantially equal to the length of walls  48  of pockets  45 , so that, in actual use, walls  48  are fed between helical folding devices  43 .  
         [0029]    In actual use, wheels  36 ,  38  and  40  of machine  34  rotate continuously and steadily about respective axes  37 ,  39  and  41 ; blanks  8  are supplied successively by wheel  38  and transferred from wheel  38  to wheel  36  at station  58 ; each blank  8  is conveyed on wheel  38  in the flat configuration shown in FIG. 2, and is retained by suction on respective head  50 , the face  52  of which contacts portion  9  of blank  8 ; up- and downstream from transfer station  58 , each head  50  and a respective pocket  45  are oriented about respective axes  51  and  46  so that face  52  is parallel to bottom wall  47 ; along a portion of path P 1  at transfer station  58 , walls  48  of pocket  45  are tilted with respect to wall  47 ; pocket  45  and head  50  are so oriented that blank  8  is transferred to pocket  45  in a movement, relative to pocket  45 , substantially perpendicular to wall  47 ; and walls  48  are so positioned that tabs  25  and  26  are folded to form a given angle with respect to panel  13 , as shown in FIGS. 4 a  and  5   a . Though the given angle shown in FIG. 5 a  is about 45°, the method can also be implemented with other angles, in particular, angles of less than 90°. Tabs  25  and  26  are folded about bend lines  27 ; and tabs  30  and  32 , being connected respectively to tabs  25  and  26 , also form said given angle with respect to panels  12  and  14 .  
         [0030]    At the next conveying stage, pocket  45  keeps blank  8  in the above given position by means of suction by wall  47 , and feeds blank  8  into engagement with helical folding devices  43 , which are positioned between panel  12  and tabs  30  and between panel  14  and tabs  32  respectively. As they slide along helical folding devices  43 , tabs  30  and  32  are folded substantially squarely, with respect to tabs  25  and  26 , about respective bend lines  31  and  33 , as shown in FIGS. 4 b  and  5   b . At this stage, blank  8  travels past gumming device  42 , which provides for applying spots  62  of gum onto blank  8 . With reference to FIGS. 4 c  and  5   c , group  4  is loaded onto panel  13  of the blank, and is transferred by so orienting pockets  45  and  54  at station  59  as to keep walls  47  and  56  of two respective pockets  45  and  54  facing and parallel to each other; in which condition, group  4  is loaded onto panel  13  and retained on panel  13  by known elements (not shown) of pocket  45 . Walls  48  are then closed to bring tabs  25  and  26  into contact with group  4 , while maintaining tabs  30  and  32  perpendicular to tabs  25  and  26 , as shown in FIGS. 4 d  and  5   d , by means of helical folding devices  43 .  
         [0031]    In a variation shown in FIGS. 6 and 7, once tabs  30  and  32  are folded with respect to tabs  25  and  26 , walls  48  of pocket  45  are rotated, with respect to wall  47 , into a position substantially coplanar with wall  47 , so that tabs  25  and  26  spring back into a position coplanar with panel  13 , and tabs  30  and  32  are positioned perpendicular to panel  13 . In other words, blank  8  assumes the FIG. 6 and  7  configuration to receive group  4 . If folded at an angle close to a right-angle, tabs  25  and  26  will spring back by only a small amount into an intermediate position between a position aligned with rear panel  13  and a position tilted slightly with respect to rear panel  13 .  
         [0032]    In other words, movable walls  48  of pocket  45  are used to fold tabs  25  and  26  onto group  4  and, at the same time, to partly fold tabs  25 ,  26 ,  30  and  32  with respect to rear panel  13 , so that tabs  30  and  32  are so positioned as to be intercepted by helical folding devices  43 .