Abstract:
A method and machine for transferring packets, whereby, as a continuous line of packets is fed in a first direction, the first packet in the line is transferred in a second direction perpendicular to the first direction, while the line and the first packet continue travelling in the first direction; the first packet is subsequently conveyed in the second direction along an output path.

Description:
[0001]    The present invention relates to a method and machine for transferring packets.  
           [0002]    The present invention may be used to advantage in the packing of cigarettes, to which the following description refers purely by way of example.  
         BACKGROUND OF THE INVENTION  
         [0003]    In automatic machines for transferring packets of cigarettes, a continuous line of packets of cigarettes is fed in a feed direction to a transfer station. The line of packets travelling in the feed direction is arrested when the lead packet, i.e. the first packet in the line, intercepts an end wall at the transfer station; at which point, the lead packet is transferred in a transfer direction substantially perpendicular to the feed direction to separate the lead packet from the line; and, once transferred, the lead packet is further conveyed along an output path. The above operations are obviously repeated for each packet occupying the lead position in the line.  
           [0004]    In modern automatic machines, the line of packets is fed to the transfer station at relatively high speed to permit high output rates and prevent gaps forming between successive packets in the line. As a result, the lead packet contacts the end wall with fairly considerable force capable of damaging the lead packet. Moreover, as it is being fed in the transfer direction, the lead packet slides against the end wall, thus possibly undergoing further damage.  
         SUMMARY OF THE INVENTION  
         [0005]    It is an object of the present invention to provide a method of transferring packets, designed to eliminate the aforementioned drawbacks, and which at the same time is cheap and easy to implement.  
           [0006]    According to the present invention, there is provided a method of transferring packets, as claimed in claim  1  and, preferably, in any one of the following claims depending directly or indirectly on claim  1 .  
           [0007]    According to the present invention, there is also provided a machine for transferring packets, as claimed in claim  15  and, preferably, in any one of the following claims depending directly or indirectly on claim  15 . 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0009]    [0009]FIG. 1 shows a plan view of a machine for transferring packets of cigarettes in accordance with the present invention;  
         [0010]    [0010]FIG. 2 shows a larger-scale side view of a detail of the FIG. 1 machine;  
         [0011]    [0011]FIG. 3 shows the FIG. 2 detail in a subsequent operating position;  
         [0012]    [0012]FIG. 4 shows a longitudinal section of FIG. 3 with parts removed for clarity;  
         [0013]    [0013]FIG. 5 shows a graph of operation of the FIG. 1 machine. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    Number  1  in FIG. 1 indicates as a whole a machine for transferring substantially parallelepiped-shaped packets  2 , in particular packets of cigarettes, from a known packing machine not shown.  
         [0015]    With reference to FIGS. 1, 2 and  3 , machine  1  comprises a feed unit  3  for feeding packets  2  horizontally in a feed direction A to a transfer station  4 ; and a transfer unit  5  for transferring at least one packet  2   a , located at transfer station  4 , to an output station  6  in a transfer direction B substantially perpendicular to feed direction A.  
         [0016]    Feed unit  3  comprises a conveyor belt  7  which feeds packets  2  to a further two-belt conveyor  8 . Conveyor  8  feeds the packets to transfer station  4 , is located downstream from conveyor belt  7 , and comprises a top conveying assembly  9  and a bottom conveying assembly  10  defining, in between, a feed channel  11  for packets  2 .  
         [0017]    Each conveying assembly  9 ,  10  comprises a drive pulley  12 , and a number of—in the example shown, five—idle pulleys  13 ; and the respective pulleys  12  and  13  of the two assemblies are located on opposite sides of channel  11 .  
         [0018]    Each conveying assembly  9 ,  10  comprises a belt  14  looped about relative pulleys  12  and  13  and which engages the walls of packets  2  to feed packets  2  in feed direction A.  
         [0019]    Conveying assembly  9  has a known guide device (not shown) for raising conveying assembly  9  to adjust the distance between it and conveying assembly  10 ; and a known locking device (not shown) operated by a lever  15  to lock conveying assembly  9  in a given position.  
         [0020]    Conveyor  8  comprises an electric motor  16  for driving pulleys  12  by means of a belt  17  (shown schematically in FIG. 4) which is kept taut by a tension pulley  18 .  
         [0021]    Finally, conveyor  8  comprises a slide plate  19  located immediately downstream from conveying assembly  10  and having a top slide surface substantially coplanar with a bottom surface of channel  11 .  
         [0022]    Transfer unit  5  comprises a lifter  20 , in turn comprising a lift head  21 ; and a rod  22 , one end of which is integral with lift head  21 , and the other end of which is connected by a cam follower to a cam  23  rotated about a respective axis by a motor M (FIG. 4). As can be seen, the length, in feed direction A, of lift head  21  is shorter than the length, in feed direction A, of the wall of packet  2   a.    
         [0023]    In actual use, lift head  21  intercepts packet  2   a  at transfer station  4 , and moves upwards in transfer direction B to transfer it to output station  6 .  
         [0024]    Machine  1  also comprises a conveying unit  24  located downstream from transfer unit  5  to convey packets  2   a  along an output path from output station  6 . Unit  24  comprises a push device  25  for feeding packet  2   a  at output station  6  onto a belt conveyor  26 .  
         [0025]    Finally, machine  1  comprises a sensor  27  for detecting any gaps between packets  2  inside channel  11 ; and a sensor  28  for detecting the position of a second packet  2   b  behind packet  2   a  in feed direction A. Sensors  27  and  28  are connected to a known control unit (not shown) which controls the speed of motor  16  as a function of the position of lift head  21 . The speed of motor  16  is also adjusted on the basis of the position of packet  2   b  determined by sensor  28 . More specifically, if packet  2   b  is ahead with respect to a given predetermined position, motor  16  is slowed down accordingly. When sensor  27  detects, in use, a gap between packets  2  in channel  11 , the known control unit (not shown) arrests motor  16  and motor M.  
         [0026]    In use, the individual incoming packets from the known packing machine (not shown) are fed by conveyor belt  7  to conveyor  8  at a constant speed greater than the maximum travelling speed of conveyor  8 . Upstream from conveyor  8  and inside channel  11 , a continuous line  29  of packets  2  is formed, and of which packet  2   a  is the lead packet in feed direction A. On the basis of the length of line  29 , which is determined by known sensors (not shown), the known control unit (not shown) adjusts the speed of motor M of transfer unit  5  so that the longer line  29  is, the greater the speed of motor M of transfer unit  5  is.  
         [0027]    The line  29  of packets  2  inside channel  11  is fed by conveyor  8  to transfer station  4  in feed direction A. When packet  2   a  is positioned correctly at transfer station  4  so as to be partly supported by lift head  21 , head  21  is moved vertically upwards in transfer direction B. As packet  2   a  is being raised, line  29  continues moving so that packet  2   b  pushes packet  2   a  in feed direction A until packet  2   a  reaches output station  6  and is separated completely from line  29 .  
         [0028]    It should be stressed that the movements of lift head  21  and the speed at which conveyor  8  conveys line  29  are so regulated that packet  2   a  never comes into contact with an end wall  30  located at the end of transfer station  4  in feed direction A.  
         [0029]    At this point, push device  25  is operated so that packet  2   a  at the output station is fed along the output path defined at least partly by conveyor  26 . Lift head  21  moves back and forth in transfer direction B so as to move down after feeding packet  2   a  to output station  6 .  
         [0030]    In this connection, it should be stressed that the movements of lift head  21  and the travelling speed of line  29  are so regulated that head  21  does not interfere with the travel of line  29  inside transfer station  4 . More specifically, the travelling speed of line  29  in feed direction A varies as a function of the position of lift head  21 , and therefore in a definite manner with time.  
         [0031]    The FIG. 5 graph shows, purely by way of example, the travelling speed of line  29  (y axis) as a function of the machine angle of transfer unit  5  (x axis). In FIG. 5, portion C-D represents the downward movement of lift head  21 , point E represents the instant in which head  21  begins moving upwards, and portion E-C represents the upward movement of head  21  (i.e. transfer of packet  2   a  in transfer direction B).  
         [0032]    The travelling speed of line  29  along portion C-D is relatively low (in particular, less than or equal to the speed along portion D-C) and reaches a maximum when lift head  21  is positioned beneath transfer station  4 . Head  21  therefore has enough time to move downwards without coming into contact with line  29 , and without interfering with the movement of line  29  in feed direction A. The travelling speed of line  29  typically slows down along portion E-C.  
         [0033]    It should be pointed out that the travelling speed of line  29  in feed direction A is also preferably varied as a function of the position of packet  2   b  as head  21  begins moving upwards. For which purpose, the real position of packet  2   b  is determined the instant packet  2   a  begins to be lifted, and is compared with an ideal theoretical position. When packet  2   b  falls short of the ideal position, the travelling speed is increased slightly with respect to that shown by way of example in FIG. 5; and, conversely, if packet  2   b  is ahead of the ideal position, the travelling speed is reduced slightly with respect to that shown by way of example in FIG. 5.