Abstract:
A method and machine for producing a package of tobacco articles complete with a folded coupon, whereby a flat strip is unwound off a reel and fed to a folding station where the strip is folded over along at least one fold line parallel to the travelling direction of the strip; the folded strip is then fed to a cutting station, where the folded strip is cut along a cutting line crosswise to the travelling direction of the strip to detach from the strip the folded coupon, which is engaged by a gripping head cooperating with the cutting station, and is fed to a seat on a packing conveyor and onto a packet of tobacco articles carried by the seat.

Description:
[0001]    The present invention relates to a method and machine for producing a package of tobacco articles complete with a folded coupon.  
           [0002]    The present invention may be used to particular advantage in the manufacture of packets of cigarettes, to which the following description refers purely by way of example.  
           [0003]    It is fairly common practice to combine a packet of cigarettes with a respective coupon, which is normally located on the group of cigarettes inside the packet. The coupon may be the same size as or larger than the packet of cigarettes, and, if larger, is folded for insertion inside or application to the outside of the packet.  
         BACKGROUND OF THE INVENTION  
         [0004]    A known packing machine for producing packets of cigarettes with respective folded coupons comprises a conveyor for feeding a number of seats, each supporting a respective group of cigarettes, along a packing path. The packing path extends through a feed station, where a wheel with a number of gripping heads extracts the folded coupons one by one from the bottom of a stack housed inside a store, and feeds each folded coupon to a respective seat on a packing conveyor and onto the corresponding group of cigarettes.  
           [0005]    Tests have shown that known packing machines of the type described above only operate satisfactorily at relatively slow speed (up to 4-5 packets of cigarettes a second), whereas high-speed operation (over 7-8 packets of cigarettes a second) is seriously impaired by the relatively long time involved in correctly withdrawing a folded coupon from the bottom of a stack of folded coupons.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to provide a method and machine for producing a package of tobacco articles complete with a folded coupon, designed to eliminate the aforementioned drawbacks, and which, in particular are cheap and easy to implement.  
           [0007]    According to the present invention, there is provided a method of producing a package of tobacco articles complete with a folded coupon, as claimed in claim  1  and, preferably, in any one of the following claims depending directly or indirectly on claim  1 .  
           [0008]    According to the present invention, there is provided a machine for producing a package of tobacco articles complete with a folded coupon, as claimed in claim  11  and, preferably, in any one of the following claims depending directly or indirectly on claim  11 . 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0010]    [0010]FIG. 1 shows a schematic view in perspective of part of a cigarette packing machine in accordance with the present invention;  
         [0011]    [0011]FIG. 2 shows a front view of the part of the machine in FIG. 1;  
         [0012]    [0012]FIG. 3 shows a side view of the part of the machine in FIG. 1;  
         [0013]    FIGS.  4  to  8  show larger-scale sections along lines IV-IV, V-V, VI-VI, VII-VII, VIII-VIII of details of the FIG. 1 machine;  
         [0014]    [0014]FIG. 9 shows a view in perspective of a packet of cigarettes produced on the FIG. 1 packing machine;  
         [0015]    [0015]FIG. 10 shows a larger-scale view in perspective of a cutting station of the FIG. 1 machine;  
         [0016]    [0016]FIGS. 11 and 12 show larger-scale front views of two instants in the operation of a cutting station of the FIG. 1 machine;  
         [0017]    [0017]FIG. 13 shows a view in perspective of a different embodiment of a folding station of the FIG. 1 packing machine.  
         [0018]    [0018]FIG. 14 shows a view in perspective of a further embodiment of a folding station of the FIG. 1 packing machine;  
         [0019]    [0019]FIG. 15 shows a side view of the FIG. 14 folding station;  
         [0020]    [0020]FIG. 16 shows a larger-scale view in perspective, with parts removed for clarity, of two details of the FIG. 14 folding station, and a plan view of one of the two details. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Number  1  in FIG. 1 indicates as a whole a packing machine for producing rigid packets  2  of cigarettes. FIG. 9 shows a detail of a packet  2  of cigarettes, which comprises a foil wrapping  3  containing a group of cigarettes (not shown in detail) and inserted inside a hinged-lid box  4 . Packet  2  of cigarettes also comprises a respective folded coupon  5 , which rests on a major lateral wall of box  4  and is made integral with box  4  by the interposition of glue or by a subsequent overwrapping of transparent plastic material (not shown). Alternatively, folded coupon  5  may be inserted inside box  4 ; in which case, folded coupon  5  rests on a major lateral wall of foil wrapping  3 .  
         [0022]    Packing machine  1  comprises a packing wheel  6  rotating continuously about a respective central axis (not shown) and having a number of peripheral seats  7 , each for housing and supporting a respective packet  2  of cigarettes. As packing wheel  6  rotates, each seat  7  housing a respective packet  2  of cigarettes is fed through a feed station  8 , where a transfer drum  9 , having three suction gripping heads  10 , feeds a respective folded coupon  5  onto the packet  2  of cigarettes in each seat  7 . More specifically, each seat  7  has known gripping means (not shown) for retaining respective folded coupon  5  on the corresponding packet  2  of cigarettes.  
         [0023]    As shown in FIGS.  1  to  3 , packing machine  1  comprises an unwinding device  11  for unwinding a flat strip  12  off a reel  13 ; a folding station  14  where the flat strip  12  unwound off reel  13  is folded over along a number of fold lines  15  parallel to the travelling direction of strip  12 ; and a cutting station  16  where the folded strip  12  is cut along a cutting line crosswise to the travelling direction of strip  12  to cut the folded coupon  5  off strip  12 , after which, the folded coupon is engaged by the gripping head  10  cooperating with cutting station  16 , and is fed to respective seat  7  on packing wheel  6 .  
         [0024]    At folding station  14  in the accompanying drawings, flat strip  12  is folded over along two fold lines  15  to a quarter of its original width. Generally speaking, however, flat strip  12  may be folded over at folding station  14  along any number of fold lines  15  to form a so-called “accordion” fold.  
         [0025]    To make each fold in flat strip  12 , flat strip  12  is run against a roller  17  having a V-shaped lateral surface, so as to be first folded into a V along a fold line  15 ; and the V-folded strip  12  is then fed between two rollers  18 , which cooperate with each other to complete the fold along fold line  15 . More specifically, roller  17  is fitted to a respective frame  19  to rotate freely about an axis  20  crosswise to the travelling direction of strip  12 .  
         [0026]    Downstream from folding station  14  is located a drive device  21 , which comprises two rollers  22  cooperating with each other, and between which the folded strip  12  is fed; one of rollers  22  is idle, while the other roller  22  is powered to impart a given motion to folded strip  12 . Downstream from drive device  21  is located a further drive device  23 , which comprises two rollers  24  cooperating with each other, and between which the folded strip  12  is fed; one of rollers  24  is idle, while the other roller  24  is powered to impart a given motion to folded strip  12 .  
         [0027]    Between the two drive devices  21  and  23  is interposed a compensating device  25 , which, by means of suction, forms a bend  26  of variable length in folded strip  12 .  
         [0028]    In actual use, drive device  21  is controlled to impart a substantially constant speed to strip  12  unwound off reel  13 , and so feed strip  12  continuously to folding station  14 ; whereas drive device  23  is controlled to impart a cyclically varying speed to strip  12 , and so feed strip  12  in steps to cutting station  16 . The length of bend  26  is varied constantly to cyclically zero the speed of strip  12  at cutting station  16 , so that strip  12  can be fed in steps to cutting station  16 .  
         [0029]    Cutting station  16  comprises a fixed anvil  27  and a movable cutting member  28  located successively in the travelling direction of strip  12 . Anvil  27  has a face  29  positioned contacting strip  12  and having a cutting edge at the end facing cutting member  28 ; and cutting member  28  comprises a plate  30 , which is mounted to oscillate about a respective axis  31  crosswise to the travelling direction of strip  12  under the control of an actuating device  32 , and has, at the end facing anvil  27 , a cutting edge complementary to the cutting edge of anvil  27 .  
         [0030]    Transfer drum  9  rotates continuously about a respective central axis  33  parallel to axis  31 , and comprises three arms  34 , which are equally spaced along the periphery of transfer drum  9 , are fitted to transfer drum  9  to oscillate with respect to transfer drum  9  about respective axis  35  parallel to axis  33 , and support gripping heads  10 .  
         [0031]    In actual use, for each complete back and forth oscillation about axis  31 , plate  30  cuts a folded coupon  5  off folded strip  12  by cutting along a cutting line crosswise to the travelling direction of strip  12 . As it is being cut off, folded coupon  5  is engaged by a respective gripping head  10  and then fed to a corresponding seat  7 . For which purpose, the arm  34  supporting gripping head  10  is oscillated about respective axis  35  to keep gripping head  10  in substantially stationary contact with plate  30 . More specifically, when cutting folded strip  12 , plate  30  (defining a cutting knife) and respective gripping head  10  are oscillated, in time with each other, about substantially the same axis coincident with axis  31 , and with concordant, substantially equal movements to keep plate  30  and gripping head  10  substantially contacting each other, with the folded coupon  5  just detached from folded strip  12  in between.  
         [0032]    As stated, at folding station  14 , to form each fold in strip  12 , strip  12  is first folded into a V along a fold line  15 , and the V-folded strip  12  is then fed between two rollers  18  cooperating with each other to complete the fold along fold line  15 .  
         [0033]    In a preferred embodiment shown in FIG. 13, strip  12  is first folded into a V by running it against a fixed triangular folding edge  36 . This solution is generally preferable to rollers  17  by being cheaper and easier to implement, while producing the same results. More specifically, folding edge  36  is flat and in the form of an isosceles (or possibly equilateral) triangle having a base  37  perpendicular to the travelling direction of strip  12 , and the vertex  38 , opposite base  37 , facing fold line  15 .  
         [0034]    [0034]FIGS. 14 and 15 show a different embodiment of folding station  14 . To form each fold in strip  12 , strip  12  is run against a folding profile  39  (shown in detail in FIG. 16, in which strip  12  is not shown) having a folding edge  40 , which slopes at a given angle of normally 10° to 30° with respect to the travelling direction of strip  12 , and therefore with respect to the fold line  15  along which strip  12  is to be folded. Folding profile  39  is shaped to have, in the travelling direction of strip  12 , a varying transverse dimension, which equals that of the non-folded strip  12  at an initial portion  41 , and is gradually reduced, by the slope of folding edge  40 , to a transverse dimension, at an end portion  42 , equal to half the transverse dimension of strip  12  (i.e. the transverse dimension of the folded strip  12 ). A deflecting member  43  holds strip  12  in contact with end portion  42  at folding edge  40 , so as to force strip  12  to fold gradually about folding edge  40  along the whole length of folding profile  39 , until it is eventually folded in half along respective fold line  15  at end portion  42  of folding profile  39 .  
         [0035]    End portion  42  of folding profile  39  preferably extends a given length in the travelling direction of the strip, with a constant transverse dimension equal to half the transverse dimension of the non-folded strip  12  (i.e. equal to the transverse dimension of the folded strip  12 ), and has a change in slope ( 44 ) at the part contacting deflecting member  43 .  
         [0036]    In other words, strip  12  is folded about folding profile  39  so that folding profile  39  is enclosed between the two halves of strip  12 ; one half of strip  12  contacts a top surface  45  of folding profile  39 ; and the other half of strip  12  is gradually brought into contact with a bottom surface  46  of folding profile  39  parallel to and opposite top surface  45 .  
         [0037]    A guide or swerve-inhibiting device  47  is preferably provided to keep the portion of strip  12  not being folded laid flat in a given position on top surface  45  of folding profile  39 . More specifically, guide device  47  comprises a perforated belt  48  looped about two end pulleys  49  and  50  and connected to a suction chamber  51  for generating suction through belt  48 . Pulley  49  is powered to rotate in time with the travelling speed of strip  12 , while pulley  50  is idle. Pulley  49  is preferably also used as a return pulley for strip  12 . In an alternative embodiment, both pulleys  49  and  50  are mounted idly to rotate freely about respective central longitudinal axes, and pulley  49  is designed and located to also define a return pulley of strip  12  and therefore to be rotated by strip  12  itself.  
         [0038]    In actual use, perforated belt  48  advances at the same speed as strip  12 , engages the contacting strip  12  by suction, and so keeps the, portion of strip  12  not being folded laid flat in a given position on top surface  45  of folding profile  39  to prevent strip  12  from swerving, and also prevent the formation of wrinkles or creases.  
         [0039]    In the embodiment shown, deflecting member  43  is defined by a roller mounted idly to rotate freely about a respective longitudinal axis of symmetry. In an alternative embodiment, deflecting member  43  is defined by a fixed drum.  
         [0040]    A known suction-type compensating device  52  is preferably provided immediately downstream from reel  13  (and therefore upstream from folding station  14 ) to form a bend of varying length in strip  12 , and so compensate, with no damage, for any sharp changes in the tension of strip  12  caused by folding station  14 .