Abstract:
A method of producing soft packets of cigarettes, whereby an inner packet, as it is fed along a packing path, is mated with a sheet of packing material withdrawn in a direction tangential with respect to the packing path; the sheet of packing material being folded into a U about the inner packet, so that a first end portion of the sheet of packing material contacts a minor lateral surface of the inner packet, and being further folded to form a tubular package which is subsequently closed at the end; the tubular package being closed laterally by detaching the first end portion from the relative minor lateral surface, and inserting, beneath the first end portion, a second end portion, an outer surface of which has been gummed beforehand.

Description:
[0001]    The present invention relates to a method of producing soft packets of cigarettes.  
           [0002]    More specifically, the present invention relates to a method of producing soft packets of cigarettes comprising a substantially rectangular-prism-shaped inner packet, and a cup-shaped outer package formed by folding a sheet of packing material about the relative inner packet.  
         BACKGROUND OF THE INVENTION  
         [0003]    According to known methods of producing soft packets of cigarettes (for example as disclosed in EP 1052171), a group of cigarette is fed in a pocket of an endless conveyor along a packing path, and through a supply station for supplying a relative sheet of packing material. The sheet of packing material is removed from the supply station by a gripper, which moves with the pocket, tangentially with respect to said packing path and is then fed along the packing path together with the group of cigarettes.  
         SUMMARY OF THE INVENTION  
         [0004]    It is an object of the present invention to improve packing methods of producing soft packets, by increasing the speed and precision with which the packing procedures are performed, and by minimizing and, at the same time, simplifying the devices required to perform the packing procedures.  
           [0005]    According to the present invention, there is provided a method of producing soft packets of cigarettes comprising a substantially rectangular-prism-shaped inner packet, and a cup-shaped outer package formed by folding a sheet of packing material about the relative inner packet; said inner packet being fed continuously along a packing path extending through a supply station for supplying a relative said sheet of packing material; said sheet of packing material being removed from said supply station tangentially with respect to said packing path, and then being fed along said packing path in a given feed direction together with said inner packet; said inner packet being fed through said supply station inside a relative first conveying pocket; said sheet of packing material being removed from said supply station by feeding gripping means continuously through the supply station, along at least a portion of said packing path, together with said first conveying pocket, in said feed direction; the method being characterized by imparting a reverse movement to said gripping means to substantially arrest the gripping means at said supply station in such a position as to interfere with said sheet of packing material being fed to said supply station; closing said gripping means on to said sheet of packing material; and arresting said reverse movement.  
           [0006]    In the method defined above, said sheet of packing material is preferably fed to said supply station in a transverse direction crosswise to said packing path and to said feed direction.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0008]    [0008]FIG. 1 shows a schematic side view, with parts in block form and parts removed for clarity, of a preferred embodiment of a packing machine for producing soft packets and implementing the method according to the present invention;  
         [0009]    [0009]FIG. 2 shows a larger-scale view of a first FIG. 1 detail at two distinct operating steps;  
         [0010]    [0010]FIG. 3 shows a larger-scale, partly sectioned view of a second FIG. 1 detail at three distinct operating steps;  
         [0011]    [0011]FIG. 4 shows a larger-scale view, with parts removed for clarity, of a third FIG. 1 detail;  
         [0012]    [0012]FIG. 5 shows a larger-scale, partly sectioned view of a FIG. 4 detail at three distinct operating steps;  
         [0013]    [0013]FIG. 6 shows, in perspective, a folding sequence of an outer sheet of packing material;  
         [0014]    [0014]FIG. 7 shows a schematic front view of the FIG. 1 packing machine with a protective casing;  
         [0015]    [0015]FIGS. 8 and 9 show two larger-scale views of a detail in FIG. 7;  
         [0016]    [0016]FIG. 10 shows a side section, with parts removed for clarity, of the FIG. 7 packing machine with a panel of the protective casing in the closed position;  
         [0017]    [0017]FIG. 11 shows a side section, with parts removed for clarity, of the FIG. 7 packing machine with a panel of the protective casing in the open position;  
         [0018]    [0018]FIG. 12 shows a larger-scale front section, with parts removed for clarity, of a control station of the FIG. 1 packing machine;  
         [0019]    [0019]FIG. 13 shows a side view, with parts removed for clarity, of the FIG. 12 control station. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    Number  1  in FIG. 1 indicates as a whole a packing machine for producing soft packets, and comprising a known input unit  2  substantially identical with corresponding units used on packing machines for producing rigid hinged-lid packets.  
         [0021]    Input unit  2  comprises a module  3  for forming groups  4  of cigarettes; a packing module  5  for receiving a succession of groups  4  and relative sheets  6  of packing material, normally foil, from module  3 , and for supplying at the output a succession of inner packets  7 , each defined by a relative group  4  enclosed in a relative foil package formed by folding relative sheet  6  of packing material; and a further packing module  8  for receiving successive inner packets  7  from packing module  5  and relative sheets  9  of packing material, normally paper, from a supply unit  10 , for folding sheets  9  of packing material about relative inner packets  7  to form, with each sheet  9  of packing material, a cup-shaped outer package  11  of a respective finished soft packet  12 , and for feeding packets  12  successively to an output conveyor  13 .  
         [0022]    Each inner packet  7  is in the form of a substantially rectangular prism, comprises a longitudinal axis  14 , two major lateral surfaces  15  parallel to each other and to longitudinal axis  14 , two minor lateral surfaces  16  parallel to each other and to longitudinal axis  14  and perpendicular to major lateral surfaces  15 , and two end surfaces  17  and  18  parallel to each other and perpendicular to longitudinal axis  14 , and leaves input unit  2  in a direction crosswise to its longitudinal axis (perpendicular to the FIG. 1 plane) and with a major lateral surface  15  facing forwards.  
         [0023]    Packing module  8  comprises a transfer conveyor defined by a transfer wheel  19 , which is substantially tangent to the output of input unit  2  at a transfer station  20  and provides for receiving inner packets  7  successively from input unit  2 , and for feeding inner packets  7  continuously in a direction  21  along a first portion of a packing path P and through a supply station  22  where each inner packet  7  is associated with a respective sheet  9  of packing material.  
         [0024]    Packing module  8  also comprises a folding conveyor defined by a folding wheel  23  for receiving inner packets  7  and relative sheets  9  of packing material at a transfer station  24  located along packing path P and downstream from supply station  22  in direction  21 , and for feeding them, still in direction  21 , along a further portion of packing path P to form a relative outer package  11  about each inner packet  7  and so form relative packet  12 .  
         [0025]    On folding wheel  23 , each packet  12  is formed by first forming, about relative inner packet  7 , a tubular package  25  coaxial with longitudinal axis  14  of relative inner packet  7  and having a minor lateral wall defined by two superimposed, gummed end portions  26  and  27  of relative sheet  9  of packing material, and an axial tubular appendix  28  defined by a respective lateral portion  29  of relative sheet  9  of packing material projecting axially from end surface  18  of relative inner packet  7 . Tubular appendix  28  comprises two major walls  30  substantially coplanar with relative major lateral surfaces  15  of relative inner packet  7 ; and two minor lateral walls  31  substantially coplanar with relative minor lateral surfaces  16  of relative inner packet  7 .  
         [0026]    Once tubular package  25  is formed, outer package  11  is completed by closing the end of tubular package  25  by folding relative tubular appendix  28  on to relative end surface  18 , and the packets  12  leaving packing module  8  are transferred successively to output conveyor  13  at a transfer station  32 .  
         [0027]    As shown in FIGS. 1 and 3, transfer wheel  19  is fitted to a front wall of a frame  33  (FIG. 7) in a position substantially tangent to the output of packing module  5 , rotates continuously anticlockwise, in FIG. 1, about an axis  34  crosswise to feed direction  21 , and comprises a powered disk  35  coaxial with and rotating about axis  34 , and a number of gripping heads  36  equally spaced about axis  34  and each comprising an arm  37  fitted to disk  35  to oscillate, with respect to disk  35  and under the control of a known cam device (not shown), about a respective axis  38  parallel to axis  34 . As shown more clearly in FIG. 2, each arm  37  extends along an axis  39  radial with respect to relative axis  38 , and is fitted on the free end with a substantially rectangular plate  40  perpendicular to respective axis  39  and for supporting a relative inner packet  7  positioned with its longitudinal axis  14  perpendicular to the FIG. 1 plane, and with a major lateral surface  15  contacting plate  40 .  
         [0028]    Plate  40  defines the base of a respective conveying pocket  41  which, in addition to plate  40 , also comprises a lateral gripper  42  defined by two flat jaws  43  projecting outwards from plate  40  and connected to respective opposite lateral edges of plate  40  to oscillate, about respective axes  44  parallel to relative axis  38 , between a closed position (FIG. 2 b ) wherein jaws  43  are substantially perpendicular to relative plate  40 , and an open position (FIG. 2 a ) wherein jaws  43  diverge outwards. Each pocket  41  also comprises a further lateral gripper  45  defined by two substantially L-shaped jaws  46  projecting outwards from plate  40  and connected to respective opposite lateral edges of plate  40  to oscillate, about respective axes  47  crosswise to relative axis  38 , between a closed position (FIG. 2 b ) wherein jaws  46  are substantially perpendicular to relative plate  40 , and an open position (FIG. 2 a ) wherein jaws  46  diverge outwards. When all in the closed position, jaws  43  and  46  define, together with relative plate  40 , a prismatic seat  48  for receiving and radially retaining, by means of jaws  46 , a relative inner packet  7 .  
         [0029]    As shown in FIGS. 1 and 3, transfer wheel  19  comprises a further number of gripping heads or grippers  49 , each of which is interposed between a pair of adjacent gripping heads  36  and is associated functionally with the gripping head  36  immediately upstream in feed direction  21 . Each gripper  49  oscillates, with respect to disk  35  and under the control of a known cam device (not shown), about a respective axis  50  parallel to axis  34 , and comprises two jaws  51  and  52  hinged to disk  35  to oscillate, with respect to each other about relative axis  50  and under the control of a known cam device (not shown), between an open and a closed position. More specifically, jaw  51 , upstream from jaw  52  in feed direction  21 , has an intermediate transverse plate  53  extending towards relative jaw  52  and defining a stop for the front edge of a respective sheet  9  of packing material fed by supply unit  10  to supply station  22  in a direction  54  substantially radial with respect to disk  35  and crosswise to packing path P at supply station  22 . Jaw  52 , on the other hand, is fitted on the free end with a pad  55  which cooperates with an end portion of relative jaw  51  to grip a front portion of a respective sheet  9  of packing material positioned with its front edge on relative plate  53 .  
         [0030]    As shown more clearly in FIG. 3, supply unit  10  comprises a powered conveyor  56  looped about pulleys  57  and having a work branch  58  extending in direction  54  and contacting a suction box  59 ; and a further powered conveyor  60  defining, with conveyor  56 , an outlet  61  of supply unit  10 , and located downstream from conveyor  56  in feed direction  21 . Conveyor  60  is looped about pulleys  62  and has a work branch  63  extending along packing path P, substantially in feed direction  21 , and contacting a suction box  64  immediately upstream from a fixed suction plate  65  extending about axis  34  between supply station  22  and transfer station  24 .  
         [0031]    In actual use, each gripping head  36  and relative gripper  49  are fed continuously, both in the open position, to transfer station  20  where gripping head  36 , oscillating in known manner about relative axis  38 , receives a relative inner packet  7  inside seat  48  of respective pocket  41  and retains it by moving relative grippers  42  and  45  into the closed position.  
         [0032]    The closed gripping head  36  and the open gripper  49  are then fed (FIG. 3 a ) by disk  35  towards supply station  22 , which is reached first by gripper  49  and then by relative gripping head  36 .  
         [0033]    Close to supply station  22 , gripper  49  is oscillated about relative axis  50  to rotate first in the same direction as and then in the opposite direction to disk  35 , which opposite rotation is tantamount to reversing and temporarily arresting the free end of gripper  49  in a position facing outlet  61  of supply unit  10 , and relative plate  53  in a position crosswise to direction  54  to intercept the front edge of a sheet  9  of packing material fed through outlet  61  by supply unit  10  and in time with the arrival of gripper  49  at supply station  22 . As the front edge of sheet  9  of packing material contacts plate  53 , jaws  51  and  52  are moved into the closed position so that pad  55  clamps a front portion of sheet  9  of packing material against the portion of jaw  51  projecting beyond plate  53 . At this point, the reverse movement of gripper  49  is arrested to enable gripper  49  to leave supply station  22 , taking with it relative sheet  9  of packing material which is removed from outlet  61  in direction  21 , i.e. in a tangential direction with respect to packing path P.  
         [0034]    In connection with the above, it should be stressed that removing sheet  9  of packing material in a tangential direction with respect to packing path P and the possibility of regulating the speed of relative gripper  49  in direction  21  enable gripper  49  to grip sheet  9  of packing material extremely accurately and so position it in an extremely precise given position—described later on with respect to relative inner packet  7 .  
         [0035]    As it is fed towards transfer station  24 , sheet  9 , the front portion of which is retained firmly by relative gripper  49 , trails behind gripper  49  with an outer surface  9   a  contacting an inner suction surface of plate  65 , and is smoothed out (FIG. 3 b ) by the pneumatic braking action of plate  65  so that an intermediate portion contacts the outer major lateral surface  15  of relative inner packet  7  carried by the adjacent upstream gripping head  36 . More specifically, the sheet is positioned, with respect to relative inner packet  7 , so that end portion  26  projects rearwards of the rear minor lateral surface  16  of inner packet  7 .  
         [0036]    Folding wheel  23  is fitted to frame  33  (FIG. 7) in a position substantially tangent to transfer wheel  19 , rotates continuously clockwise in FIG. 1 about an axis  66  parallel to axis  34 , and comprises a powered disk  67  coaxial with and rotating about axis  66 , and a number of gripping heads  68  equally spaced about axis  66  and fitted to disk  67  to oscillate, with respect to disk  67  and under the control of known cam device (not shown), about respective axes  69  parallel to axis  66 .  
         [0037]    As shown more clearly in FIGS. 4 and 5, each gripping head  68  comprises an arm  70  hinged to disk  67  to oscillate about respective axis  69  and extending along an axis  71  radial with respect to relative axis  69 ; and a pusher  72  moved inside relative arm  70  by a known cam device (not shown) and coaxial with relative axis  71 . Each pusher  72  comprises a head  73  defined externally by a suction surface in turn defining a movable base of a respective pocket  74  for housing a respective sheet  9  of packing material and relative inner packet  7  positioned with its longitudinal axis  14  parallel to relative axis  69 , and with a major lateral surface  15  facing relative head  73 .  
         [0038]    In addition to head  73 , each pocket  74  also comprises a lateral gripper  75  defined by two flat jaws  76  and  77  projecting outwards from respective arm  70  and on opposite sides of relative head  73  in feed direction  21 . In each gripper  75 , the front jaw  76  is parallel to relative axis  71  and fixed; while jaw  77  (FIG. 5) has an inner suction surface  78  and is connected to relative arm  70  to oscillate, with respect to arm  70  and about a respective axis  79  parallel to relative axis  69 , between an open position wherein jaw  77  diverges outwards with respect to relative jaw  76 , and a closed position parallel to relative jaw  76 .  
         [0039]    As shown in FIG. 1, folding wheel  23  is associated with a known device  80  for supplying revenue stamps (not shown) and located outwards of folding wheel  23  and upstream from transfer station  24 ; a fixed guide plate  81  extending, coaxially with axis  66 , between transfer stations  24  and  32 ; a gumming device  82  located along plate  81  and outwards of wheel  23 , and operating through an opening  83  (FIG. 4) formed in plate  81  to feed glue on to the outer surface  9   a  of end portion  27  of each sheet  9  of packing material; a folding device  84  located along plate  81  and outwards of folding wheel  23 , and operating through an opening  85  (FIG. 4) formed through plate  81  at a folding station  86  to complete the folding of each sheet  9  of packing material about relative inner packet  7  and so form relative tubular package  25 ; and a known further folding device  87  supported by plate  81 , between folding station  86  and transfer station  32 , to close the ends of tubular packages  25  in known manner, and correctly fold the relative revenue stamps (not shown).  
         [0040]    Folding device  84  comprises a powered wheel  88  mounted to rotate continuously anticlockwise, in FIG. 1, about an axis  89  parallel to axis  34 ; and a number of folding heads  90  fitted to wheel  88  and equally spaced about axis  89 . Each folding head  90  comprises a crank  91  fitted to wheel  88  to oscillate with respect to wheel  88  about a respective axis  92  parallel to axis  89 ; and a folding blade  93  connected integrally to one end of relative crank  91 , crosswise to relative crank  91 , and projecting outwards, with respect to crank  91 , in a substantially radial direction with respect to wheel  88 .  
         [0041]    In actual use, and as shown in FIG. 4, each gripping head  36 , on approaching transfer station  24 , oscillates about relative axis  38  to keep axis  39  aligned, for a given period of time, with axis  71  of a corresponding gripping head  68 , which is oscillated accordingly on disk  67  and fed by folding wheel  23  to transfer station  24  in time with said gripping head  36 . Each head  36 , as it oscillates about respective axis  38 , is accompanied by relative gripper  49 , so as to hold relative sheet  9  on relative inner packet  7  in the position described previously (FIG. 6 a ), i.e. with relative end portion  26  projecting rearwards of rear minor lateral surface  16  of inner packet  7 .  
         [0042]    Gripping head  68  reaches transfer station  24  with jaw  77  open, and with pusher  72 —the head  73  of which has already received and retains the relative revenue stamp (not shown) by suction—in the extracted position; and gripping head  36  reaches transfer station  24  with gripper  42  open and gripper  45  closed, so as to retain relative inner packet  7  and enable inner packet  7  to penetrate pocket  74  of gripping head  68 , which is eased down by gradually withdrawing pusher  72 .  
         [0043]    As inner packet  7  is inserted inside pocket  74 , relative sheet  9  of packing material is folded into a U (FIG. 6 b ) with end portion  26  between jaw  77  and the minor lateral surface  16  of inner packet  7  located rearwards in feed direction  21 ; with an intermediate portion between head  73  and the inner major lateral surface  15  of inner packet  7 ; with a further intermediate portion between jaw  76  and the minor lateral surface  16  of inner packet  7  located frontwards in feed direction  21 ; with an end portion projecting outwards of pocket  74  in a substantially radial direction; and with lateral portion  29  projecting axially (with respect to axis  66 ) from pocket  74 .  
         [0044]    At this point, gripper  75  is closed and the corresponding gripper  45  opened to permit removal of inner packet  7  and relative sheet  9  of packing material by gripping head  68 , which is fed continuously towards plate  81 , which folds said projecting end portion of sheet  9  of packing material (FIG. 6 c ) on to the outer major lateral surface  15  of relative inner packet  7 , so that end portion  27  projects rearwards of rear minor lateral surface  16  of inner packet  7 .  
         [0045]    As gripping head  68  continues in feed direction  21 , end portion  27  of relative sheet  9  of packing material is first fed (FIG. 5 a ) past opening  83 , where gumming device  82  applies glue to outer surface  9   a , and then past opening  85  (FIG. 5 b ) where jaw  77  is opened to raise end portion  26  retained by suction on jaw  77 . A folding head  90 , operating through opening  85  (FIG. 5 c ), then folds end portion  27  squarely (FIG. 6 d ) inside the gap between relative end portion  26  and the rear minor lateral surface  16  of relative inner packet  7 . At this point, jaw  77  is closed to complete tubular package  25  (FIG. 6 e ), the tubular appendix  28  of which, projecting axially from relative pocket  74 , is folded in known manner (FIG. 6 f ) on to end surface  18  of relative inner packet  7  as gripping head  68  travels through folding device  87 , which completes packet  12 , which is then transferred from folding wheel  23  to output conveyor  13  at transfer station  32 .  
         [0046]    In connection with the above, it should be stressed that the procedure for completing tubular package  25 , and described above with reference to FIGS. 6 c - e , provides for gumming end portion  27  not only just before being folded, but also from the outside, with obvious advantages as regards the structure and efficiency of machine  1  as a whole, and the precision and speed with which the folding procedure is performed.  
         [0047]    As shown in FIG. 7, packing machine  1  is provided with a protective casing  101  fitted to frame  33  and divided into two lateral sections  102  and  103  on opposite sides of a central section  104 . Lateral section  102  of protective casing  101  protects group-forming module  3 , which has a hopper  105  for supplying cigarettes (not shown); central section  104  of protective casing  101  protects packing module  5  and outer packing module  8 ; and lateral section  103  of protective casing  101  protects output conveyor  13 .  
         [0048]    Lateral section  102  of casing  101  comprises a top panel  106  fixed to frame  33  by screws (not shown) and having two see-through doors  107  for viewing and access to the bottom portion of hopper  105 ; an intermediate panel  108  fixed to frame  33  by screws (not shown) and covering group-forming module  3 ; and a bottom panel  109  fitted to frame  33  to slide, in a horizontal direction  110 , between a closed position (shown in FIG. 7) and an open position (not shown).  
         [0049]    Central section  104  of casing  101  comprises a see-through top panel  111  fitted to frame  33  to move between a closed position (shown in FIGS. 7 and 10) and an open position (shown in FIG. 11); an intermediate panel  112  fixed to frame  33  by screws (not shown); and a bottom panel  113  fitted to slide, in a horizontal direction  114 , between a closed position (shown in FIG. 7) and an open position (not shown). Intermediate panel  112  has an opening  115  through which is inserted a handwheel  116  for operating packing machine  1  manually. Handwheel  116  has a grip  117 , which is movable between a rest position (not shown) wherein grip  117  is housed inside a seat  118  formed in handwheel  116 , and a work position (shown in FIG. 7) wherein grip  117  projects perpendicularly from handwheel  116 .  
         [0050]    Lateral section  103  of casing  101  comprises a door  119  which has a central window  120  protected by a see-through panel, and is hinged to rotate, about a vertical axis  121 , between a closed position (shown in FIG. 7) and an open position (not shown).  
         [0051]    Packing machine  1  has a user interface (so-called HMI) unit  122  comprising a box  123  connected by a tubular body  124  to frame  33 . Box  123  houses a monitor  125  for displaying information relating to the operation of packing machine  1  and preferably having touch-screen functions enabling the user to interact with user interface unit  122 , and has a number of buttons  126  (shown in FIG. 8) for user control of the main functions of packing machine  1  (typically, stop, go, emergency stop, alarm acquisition, and operating speed adjustment).  
         [0052]    Tubular body  124  houses the connecting cables of user interface unit  122 , and comprises a vertically tilted portion  127  supporting box  123  at one end and connected at the other end to a horizontal portion  128  hinged to the base of frame  33  to rotate, about a vertical axis  129 , between a work position (FIGS. 7, 8,  9 ) wherein box  123  is located in front of packing machine  1 , and a rest position (not shown) wherein body  123  is located to the side of, to permit free access to, packing machine  1 . Horizontal portion  128  is designed to position box  123  and vertical axis  129  a relatively long distance apart, so that, when rotated about axis  129 , box  123  is swung well clear of packing machine  1 . And, for compactness, horizontal portion  128  is designed to substantially contact the base of frame  33  when box  123  is in the work position.  
         [0053]    As shown in FIG. 7, frame  33  supports a known multicolor lamp  130 , i.e. having various sections of different colors; and a horizontal beam  131  housing a relatively large graphic display  132  preferably comprising a matrix of red LED&#39;s for displaying writing visible from a distance of at least 20 meters. Horizontal beam  131  is preferably located so as to be covered by the see-through top panel  111  of central section  104  of protective casing  101 .  
         [0054]    In actual use, multicolor lamp  130  shows a green light when packing machine  1  is operating normally; a red light when packing machine is idle; and a yellow light when packing machine  1  is operating but in the presence of an alarm requiring intervention on the part of the operator. When the yellow light of multicolor lamp  130  comes on, details of the type of intervention required are shown simultaneously on display  132 , so that the operator, reading display  132  some distance from packing machine  1 , can monitor operation and organize any intervention required without having to consult monitor  125  of user interface  122  on machine  1  itself. Display  132  may, obviously, also be used for displaying information when packing machine  1  is operating normally or idle, thus enabling the operator to monitor operation of packing machine  1  from a relatively long distance.  
         [0055]    As shown in FIG. 10, top panel  111  comprises a rigid frame  133  supporting a see-through wall  134  and curved to prevent interference with packing module  5  and outer packing module  8  (shown schematically in FIG. 10). On opposite sides of panel  111 , frame  133  is fitted with two plates  135  (only one shown in FIG. 10) supporting frame  133  and hinged to respective slides  136  (only one shown in FIG. 10) to swing freely about a horizontal axis  137 . Each slide  136  is run along a respective horizontal guide  138  (only one shown in FIG. 10) by a corresponding horizontal chain  139  (only one shown in FIG. 10) connected to slide  136  by a relative connecting body  140 . Each chain  139  is looped about a pair of end sprockets: an idle sprocket  141 ; and a sprocket  142  rotated by a reversible two-way motor (not shown). Each plate  135  is fitted with a tappet roller  143  mating with a corresponding fixed cam  144  (shown schematically in FIG. 10) substantially in the form of an inclined surface.  
         [0056]    In actual use, to move top panel  111  from the closed position (shown in FIGS. 7 and 10) to the open position (shown in FIG. 11), each sprocket  142  is rotated to move respective slide  136  along relative guide  138 . As a result, plates  135  move towards the rear of packing machine  1  and, at the same time, are rotated about axis  137  by tappet rollers  143  rolling up along respective cams  144 . The rotary and linear movement of plates  135  is also transferred to top panel  111  which, being connected to plates  135 , is moved from the closed position (shown in FIGS. 7 and 10) to the open position (shown in FIG. 11). Obviously, to move top panel  111  from the open position (shown in FIG. 11) to the closed position (shown in FIGS. 7 and 10), the above operations are performed in reverse.  
         [0057]    Guides  138 , sprockets  141 ,  142  and, therefore, slides  136  and top panel  111  are supported by a beam  145  hinged to frame  33  to rotate, with respect to frame  33  and about a horizontal axis  146 , between a closed position (shown in FIGS. 10 and 11) and an open position (not shown) under the control of an actuating device comprising an arm  147  hinged to frame  33  and beam  145  and which is raised by a known hydraulic lifting device (not shown).  
         [0058]    Frame  33  is fitted with a horizontal guide  148 , along which a known crane (not shown) runs freely. When beam  145  is in the closed position (shown in FIGS. 10 and 11), guide  148  is substantially concealed from the front of packing machine  1  by various operating devices  149  (shown schematically in FIGS. 10 and 11) supported by beam  145 . Conversely, when beam  145  is in the open position (not shown), operating devices  149  are raised so that guide  148  is freely accessible from the front of packing machine  1 . More specifically, the crane (not shown) can be set to an extracted position substantially crosswise to guide  148 , and a withdrawn position substantially parallel to and contacting guide  148 .  
         [0059]    When beam  145  is in the open position (not shown), guide  148  and the crane (not shown) are freely accessible from the front of packing machine  1 , so that the crane (not shown) can be used by the operator to assemble or disassemble parts of packing machine  1 .  
         [0060]    As shown in FIGS. 12 and 13, packing machine  1  has a transfer conveyor  150  (shown partly in FIG. 7), which is a horizontal belt conveyor, receives the finished packets  151  of cigarettes from vertical output conveyor  13 , and feeds the finished packets  151  of cigarettes to a known follow-up cellophaning machine (not shown). A optical control station  152  is located along transfer conveyor  150  to ensure each packet  151  of cigarettes conforms with production specifications.  
         [0061]    Transfer conveyor  150  comprises a supporting beam  153 , along which runs a conveyor belt  154  with projections  155  defining seats for housing respective packets  151  of cigarettes; and control station  152  comprises a frame  156  fixed to supporting beam  153  and supporting a television camera  157 , two stroboscopic lamps  158 , and two mirrors  159 .  
         [0062]    Camera  157  is located over transfer conveyor  150  with its optical axis  160  perpendicular to the front wall  161  of a packet  151  of cigarettes at control station  152 , and perpendicular to the feed direction  162  of transfer conveyor  150 . Mirrors  159  have respective reflecting surfaces  163 , which are rectangular with the major sides aligned with feed direction  162  of transfer conveyor  150 , and are located on opposite sides of transfer conveyor  150  to reflect back to camera  157  a full view of the lateral walls  164  of packet  151  of cigarettes, a full view of the edges  165  between lateral walls  164  and the rear wall  166 , and a view of two end portions of rear wall  166  close to edges  165  and not resting on conveyor belt  154 .  
         [0063]    In actual use, as it is fed through control station  152 , each packet  151  of cigarettes is illuminated by a flash of light emitted by stroboscopic lamps  158  to enable camera  157  to pick up a single image comprising a complete view of front wall  161 , a complete view of lateral walls  164 , a complete view of edges  165 , and a view of two end portions of rear wall  166  close to edges  165 .