Abstract:
Known devices for the opto-electrical scanning of individual cubic or cuboid-shaped packets  10, 19,  transported at a distance from one another, have the disadvantage that they do not permit simultaneous scanning of all the packet walls. In the device according to the invention, the conveying distance  26  for transporting the packets is interrupted in the region of a testing station  27.  The packets  10, 19  to be examined are moved in this region along an aerodynamic trajectory or falling distance. Consequently, all the walls of the packets  10, 19  to be scanned may be scanned simultaneously on all sides.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a method of opto-electrical scanning of individual packets, transported at a distance from one another, such as cigarette packets, in accordance with the preamble of patent claim  1 . In addition, the invention relates to a device for the opto-electrical scanning of packets in accordance with the preamble of patent claim  4 . 
     Packets, especially cigarette packets, are very thoroughly examined in the region of a packaging machine to check that they are correctly formed. Cigarette packets are thus, for example, examined to see whether they are provided with the correct band label or whether the sides of the packet are printed completely and in accordance with the regulations—amongst other things with a safety warning. The packets are checked photographically, especially with the aid of cameras installed in a fixed position. The cameras scan outer surfaces of the packets. Data obtained by this process are compared with reference data; where there are undesired deviations, faulty packets are steered out of the production flow. 
     SUMMARY OF THE INVENTION 
     Many kinds of methods and devices for the opto-electrical scanning of cigarette packets are known. Thus U.S. Pat. No. 4,972,494 shows a device for the opto-electrical scanning of cigarette packets in which the cigarette packets lie with one wall of the packet on a conveyor and are moved in this position by the conveyor past testing devices. This scanning device has, however, the disadvantage that the wall of the packet lying on the conveyor cannot be scanned by the testing devices. Thus it is not possible to check whether the wall of the cigarette packet lying on the conveyor is correctly formed. 
     In the device for the electro-optical scanning of cigarette packets according to DE-A-38 01 388, the cuboid-shaped cigarette packets are moved past testing devices with one of the packet walls in contact with a conveyor belt affected by suction air. Free walls of the cigarette packet can be detected by a testing device arranged beside the transport path. A second conveyor belt, connected to a first conveyor belt and likewise affected by suction air, detects an opposite wall of the cigarette packet. A second testing device then detects the wall of the cigarette packet covered by the first conveyor belt and now lying free. The device according to DE-A-38 01 388 requires great constructional outlay. The conveyor belts which can be affected by suction air require a high, permanent expenditure of energy. 
     SUMMARY OF THE INVENTION 
     The problem underlying the invention, therefore, is to propose a method and a device for the opto-electrical scanning of packets, which make possible the scanning of the walls of packets on all sides with very little constructional outlay. 
     To solve this problem, the method according to the invention is characterised by the measures of patent claim  1 . Due to the fact that the packets are moved past the or each testing device along an aerodynamic trajectory or falling distance, all the walls of the packets can be scanned simultaneously with very little outlay. 
     The idea underlying the invention, therefore, is to move the packets, with the aid of an oblique, horizontal or perpendicular throw or with the aid of free fall, past the testing devices without touching them. As a result of this, all the walls of the packets lie free in the region of the testing devices. The testing devices can scan the walls of the packets unimpeded, i.e. without the interfering influence of guides or conveyor belts. 
     The device according to the invention is characterised by the features of patent claim  4 . It makes possible the simultaneous scanning of the packets on all sides with very little constructional outlay. 
     By preference, a second conveying section of a feed-in conveyor has a lower continuous conveyor and an upper continuous conveyor which grasp the packets on opposite packet walls. This guarantees exact guiding and expedition of the packets and thus an exact aerodynamic trajectory of same. 
     Preferred developments of the invention arise from the secondary claims and the specification. Embodiments of the invention, given by way of example, are explained in greater detail below with the aid of the drawing. In the drawing: 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 shows a first cigarette packet to be scanned, namely a hinge-lid packet, in perspective side view, 
     FIG. 2 shows a second cigarette packet to be scanned, namely a soft case packet, in a view analogous to FIG. 1, 
     FIG. 3 shows a device according to the invention as per a first embodiment of the invention, given by way of example, in side view, 
     FIG. 4 shows a detail of the device according to the invention as per FIG. 3 in plan view, 
     FIG. 5 shows a partial cross-section through the device according to the invention along the intersection line V—V in FIG. 3, and 
     FIG. 6 shows a device according to the invention as per a second embodiment of the invention, in perspective side view. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The embodiments shown in the drawing of a testing apparatus serve the opto-electrical scanning of cigarette packets with the aid of testing devices, namely cameras. 
     FIGS. 1 and 2 show diagrammatically cigarette packets which can be scanned with the aid of the device according to the invention. The cigarette packet according to FIG. 1 is a folding packet  10  which can also be referred to as a hinge-lid packet. The hinge-lid packet  10  consists of a packet portion  11  plus a lid  13  hinged to packet portion  11  via a hinge line  12 . The hinge-lid packet  10  is delimited by packet walls of different size, namely by a front wall, not shown, a rear wall  14 , comparatively narrow, elongated side walls  15 , a front face  16  in the region of the lid  13  and by a base wall, not shown, in the region of packet portion  11 . A band label  17  extends over a partial region of the rear wall  14  and of a side wall  15  adjoining the rear wall  14 . The band label  17  partially covers the hinge line  12  in the region of the rear wall  14  and a butt joint  18  between packet portion  11  and lid  13  in the region of the side wall  15 . 
     The cigarette packet according to FIG. 2 is a soft-case packet  19 . In a pouch  20 , open at the top, of the soft case packet  19 , there is positioned a group of cigarettes  21  wrapped in an inner wrapping made of tin foil or the like. The soft case packet  19  is also delimited by packet walls of different size. These are a front wall  22  and a rear wall, not shown. Front wall  22  and rear wall are interconnected by comparatively narrow, elongated side walls  23 . In addition, the soft case packet  19  is delimited by a base wall, not shown, in the region of the pouch  20  and a front wall  24  in the region of the group of cigarettes  21 . A strip-shaped region of the front wall  24  plus partial regions adjacent thereto of the front wall  22  and the rear wall are covered by a band label  25 . 
     With the devices according to the invention and described in detail below, it is now possible, for example, to check that the band labels  17 ,  25  are correctly applied to the hinge-lid packet  10  on the one hand or the soft case packet  19  on the other hand. 
     In first embodiment of the device according to the invention and as per FIGS. 3 to  5 , the cigarette packets  10 ,  19  produced by a packaging machine, not shown, may be transported along a conveying distance or path  26  and examined in the region of a testing station  27  to check that they are correctly formed. The conveying distance  26  is formed by a feed-in conveyor  28  and an onward conveyor  29 . With the aid of the feed-in conveyor  28 , the cigarettes packets  10 ,  19  are transported into the proximity of the testing station  27 , namely into a testing region  30 . In the area of the testing region  30  or the testing station  27 , the conveying distance or path  26  is interrupted for form an open space between the end of feed-in conveyor  28  and the beginning of onward conveyor  29 , as clearly shown in FIGS. 3 and 4, for example. The cigarette packets  10 ,  19  pass the testing station  27  along an aerodynamic trajectory. Once they have passed the testing station  27  or the testing region  30 , the cigarette packets  10 ,  19  are taken on to the onward conveyor  29 . This conveyor  29  transports the cigarette packets  10 ,  19  out of the device according to the invention, maintaining the predetermined distances of the cigarette packets  10 ,  19  from one another. 
     The feed-in conveyor  29  consists of a first conveying section  31  running horizontally plus a second conveying section  32  inclined in relation to the first conveying section  31  and thus running at an angle. In the embodiment shown here, the second conveying section  32  is inclined at an angle of approximately 5° higher than the first conveying section  31 . The cigarette packets  10 ,  19  are correspondingly moved by the second conveying section  32  of the feed-in conveyor  28  along a slightly rising sloping plane into the testing region  30 . 
     The conveying speed of the first conveying section  31  of the feed-in conveyor  28  amounts to approximately one meter per second. The second conveying section  32  of the feed-in conveyor  28  is driven at a higher speed than the first conveying section  31 . In the present case, the second conveying section  32  is driven at twice the conveying speed by comparison with the first conveying section  31 , i.e. at approximately 2 meters per second. 
     The onward conveyor  29  connects with the feed-in conveyor  28  at a distance. Like the feed-in conveyor  28 , the onward conveyor  29  consists of a first conveying section  33  running horizontally and a second conveying section  34  inclined in relation to the first conveying section  33  and thus running at an angle. The second conveying section  34  is here preferably inclined at an angle of 5° in relation to the first conveying section  33 . The conveying speeds of the conveying sections  33 ,  34  of the onward conveyor  29  are preferably adapted to the conveying speeds of the conveying sections  31 ,  32  of the feed-in conveyor  28 . The second conveying section  34  of the onward conveyor  29  is therefore driven at twice the speed in relation to the first conveying section  33 , in the present case at 2 meters per second. 
     The conveying distance or path  26  is interrupted to form the space between the inclined second conveying sections  32 ,  34  of feed-in conveyor  28  and onward conveyor  29 . The testing station  27  is arranged in this region. An end  35 , turned towards the testing station  27 , of the feed-in conveyor  28  or its second conveying section  32  and an end  36 , turned towards the testing station  27 , of the onward conveyor  29  or its second conveying section  35  accordingly enclose the testing region  30 . The ends  35 ,  36  are spaced at a distance from one another to form the open space between the conveyors  28  and  29 . The distance is by preference 80 mm. The angle of inclination of the second conveying section  32  of the feed-in conveyor  28 , whose conveying speed and the distance between the ends  35 ,  36  of feed-in conveyor  28  and onward conveyor  29  are adapted to one another in such a way that the cigarette packets  10 ,  19 , after they have passed the open space in the testing region  30  along the aerodynamic trajectory, land safely and in the correct position on the onward conveyor  29 , or its second conveying section  34 . Depending on the angles of inclination of the second conveying sections  32 ,  34  and of the or space distance between the ends  35 ,  36 , the conveying speed of the second conveying sections  32 ,  34  can vary. The necessary speed of the second conveying section  32  of the feed-in conveyor  28  for a throw adapted to the width of the testing region  30  arises from the physical basic equations relating to an upwardly-directed, oblique throw. The movement of the cigarette packets  10 ,  19  through the testing region  30  along the aerodynamic trajectory is therefore determined by the initial parameters of angle of inclination and conveying speed of the second conveying section  32 . 
     In order to guarantee that the cigarette packets  10 ,  19  are carried exactly and in the correct position through the device according to the invention, guides  37  are arranged along the conveying distance  26  on both sides of the cigarette packet  10 ,  19 . The guides  37  prevent the cigarette packets  10 ,  19  from slipping out sideways as they are carried along the conveying distance  26 . The guides  37  are fastened via cross bars  38  to carrying bars  39 ,  40  of the feed-in conveyor  28  or onward conveyor  29 . At the end  36 , turned towards the testing region  30 , of the onward conveyor  29  or its second conveying section  34 , the guides  37  form a collecting area  41  for the cigarette packets  10 ,  19 . For this purpose, the guides  37  are enlarged in a funnel shape at their ends  42 . This makes possible safe landing of the cigarette packets  10 ,  19  in the collecting area  41 . Tipping over of the packets once they have landed in the collecting area  41  on the guides  37  is excluded. 
     The first conveying section  31  of the feed-in conveyor  28  and the first  33  and second  34  conveying sections of the onward conveyor  29  are in each case formed by a continuous conveyor, namely a belt conveyor  43 ,  44 ,  45 . The cigarette packets  10 ,  19  lie on the belt conveyors  43 ,  44 ,  45  as they are transported through the conveying distance  26 . The second conveying section  32  of the feed-in conveyor  28  is formed by an upper continuous conveyor and a lower continuous conveyor, namely by an upper belt conveyor  46  and a lower belt conveyor  47 . The cigarette packets  10 ,  19  are conveyed between the conveying lengths facing one another of the belt conveyors  46 ,  47  of the second conveying section  32  of the feed-in conveyor  28 . In the region of the second conveying section  32  of the feed-in conveyor  28 , the cigarette packets  10 ,  19  are therefore grasped by the belt conveyors on two opposite packet walls. By this means, the position of the cigarette packets  10 ,  19  is stabilized before they leave the feed-in conveyor  28  and thus before they are thrown over the testing region  30 . The upper belt conveyor  46  and the lower belt conveyor  47  of the second conveying section  32  of the feed-in conveyor  28  are here driven at the same conveying speed. 
     As the cigarette packets  10 ,  19  are transported through the device according to the invention in the transport direction  48 , the cigarette packets  10 ,  19  lie with a narrow, elongated side wall  15 ,  23  first on the conveying length of the belt conveyor  43  of the first conveying section  31  of the feed-in conveyor  28 . The end wall  16 ,  24  of the cigarette packet  10 ,  19  points in the transport direction  48 . Then the cigarette packets  10 ,  19  are passed on to the second conveying section  32  of the feed-in conveyor  28 . In order to guarantee here the safe transfer of the cigarette packets  10 ,  19 , a bridge  51  is arranged between the adjacent ends  49 ,  50  of the belt conveyors  43 ,  47 . In the region of the second conveying section  32  of the feed-in conveyor  28 , the cigarette packets  10 ,  19  are grasped by the belt conveyors  46 ,  47  on both side walls  15 ,  23 . Once the cigarette packets  10 ,  19  have been thrown over the testing region  30 , they are moved by the belt conveyors  44 ,  45  of the onward conveyor  29  out of the device according to the invention. A bridge  54  is also arranged between adjacent ends  52 ,  53  of belt conveyors  44 ,  45 . 
     All the belt conveyors  43  . . .  47  are lead over deflection rollers  55 . The deflection rollers  55  of the belt conveyors  43  . . .  47  are mounted via pegs  56  in the carrying bars  49 ,  50  of feed-in conveyor  28  and onward conveyor  29 . In the region of the second conveying section  32  of the feed-in conveyor  28 , the carrying bar  39  is drawn for this purpose into the region of the upper belt conveyor  46 . 
     The conveying lengths of the belt conveyors  43 ,  44 ,  45 ,  47  are in each case stabilized by a guide plate  57 . The same is true for the upper belt conveyor  46  which is stabilized by a guide plate  58 . The guide plates  57  in the region of the belt conveyors  43 ,  44 ,  45 ,  47  prevent the conveying length facing the cigarette packets  10 ,  19  to be transported from sagging downwards. Pressure members  59 , namely leaf springs, are arranged on the conveying plate  58  of the upper belt conveyor  46  of the second conveying section  32  of the feed-in conveyor  28 . With the aid of the pressure members  59  or leaf springs, the conveying length of the upper belt conveyor  46  is pressed on to the wall of the cigarette packet  10 ,  19  facing upwards. This guarantees that cigarette packets  10 ,  19  of different formats are accurately transported and expedited. 
     The belt conveyors  44 ,  46 ,  47  of the second conveying sections  32 ,  34  of feed-in conveyor  28  and onward conveyor  29  are driven by a common drive mechanism  60 , namely a motor, at the same conveying speed. Transmission of the driving power of the drive mechanism  60  to the belt conveyors  44 ,  46 ,  47  is effected via a drive belt  61 . The drive belt  61  is led over a plurality of deflection rollers  62  into the region of belt conveyors  44 ,  46 ,  47 . Drive rollers  63  mounted coaxially with the deflection rollers  55  of belt conveyors  44 ,  46 ,  47  ultimately transmit the driving power of the drive mechanism  60  to the belt conveyors. 
     The testing station  27  is arranged in the testing region  30 . This station consists of a plurality of testing devices  64 . In the embodiment according to FIG. 3, the testing station  27  has three testing devices  64 . These are in the form of cameras. As the cigarette packets  10 ,  19  are thrown through the testing region  30 , the cigarette packets  10 ,  19  are moved past the testing devices  64  along a sloping aerodynamic trajectory. During this movement, the cigarette packets  10 ,  19  are scanned by the testing devices  64 . Since the cigarette packets  10 ,  19  are not supported on the trajectory either by belt conveyors or any other guides, the testing devices  64  can scan the cigarette packets  10 ,  19  on all sides unimpeded. 
     On the end  35  turned towards the testing region  30  or the testing station  27  of the feed-in conveyor  28  or its second conveying section  32 , there is arranged a sensor  65 . The sensor  65  is here fastened to one of the guides  37 . The sensor  65  monitors the transporting of the cigarette packets  10 ,  19  along the conveying distance  26 . If a cigarette packet  10 ,  19  is moved by the second conveying section  32  of the feed-in conveyor  38  into the testing region  30 , a control signal for the testing devices  64  of the testing station  27  is generated by the sensor  65 . The control signal of the sensor  65  activates the testing devices  64 , if necessary at a time interval from one another, so that the walls of the cigarette packet  10 ,  19  are scanned at the correct time. 
     FIG. 6 shows a second embodiment, given by way of example, of a device according to the invention for the electro-optical scanning of cigarette packets. A conveying distance  66  for the cigarette packets  10 ,  19  is formed by a pipe  67 . There is a break in the pipe  67  in a perpendicular section, i.e. one running vertically. A testing station  68  or a testing region  76  with two testing devices  69  is arranged in this region. Thus, in the conveying direction  71  before the testing station  68 , the pipe  67  forms a feed-in conveyor  74 . In the conveying direction  71  following on from the testing station  68 , the pipe  67  forms an onward conveyor  75 . 
     Whilst the cigarette packets fall through the testing station  68 , the testing devices  69  can scan all the walls of the cigarette packets  10 ,  19 . In a similar way to the embodiment according to FIGS. 3-5, the testing devices may here be controlled by a sensor  70 . 
     In a section, facing the testing station  68 , of the onward conveyor  75  or the pipe  67 , said section has a collecting area  72  for the cigarette packets  10 ,  19 . Walls  73  of the pipe  67  are enlarged in the shape of a funnel for this purpose. 
     It goes without saying that a large number of devices different from the embodiments shown in the drawing can be imagined for carrying out the method according to the invention. If the cigarette packets are to be moved along a perpendicular or even horizontal aerodynamic trajectory through a testing region, it lies within the average skill of the expert to adapt accordingly the devices shown in the drawing.