Abstract:
On a packing machine for packing cigarettes, whereby a group of cigarettes is formed by withdrawing the cigarettes from one or more outlets of a hopper, interception, in response to a control signal, of the stream of cigarettes from any one outlet results in simultaneous interception of the respective streams from all of any other outlets participating, with the intercepted outlet, in the formation of the group, but not in simultaneous stoppage of the packing machine as a whole.

Description:
The present invention relates to a method of forming groups of cigarettes on a cigarette packing machine. 
     More specifically, the present invention relates to a method of forming groups of cigarettes on a cigarette packing machine capable of forming, substantially simultaneously, at least two groups of cigarettes, each forming the content of a packet of cigarettes. 
     BACKGROUND OF THE INVENTION 
     On cigarette packing machines, groups of cigarettes are fed, at least in pairs, to at least one packing line by a supply device, which is fed in steps in a substantially horizontal direction, and comprises a number of pockets equally spaced along one or a number of parallel supply lines, and each for housing a respective group of cigarettes. 
     The cigarettes are fed to the group supply device by a hopper having an output end divided into a number of outlets arranged in at least two groups, each for forming a respective group of cigarettes. When each group of cigarettes is formed by superimposing layers, each group of outlets is defined by a number of outlets at most equal to the number of layers in each group of cigarettes. Conversely, when each group of cigarettes is formed in one go, each group of outlets is defined by a single outlet. 
     Each outlet is divided into a number of substantially vertical channels equal in number to the cigarettes in the respective layer or, if the groups of cigarettes are formed in one go, to the cigarettes in the longest layer in the respective group of cigarettes. 
     When each group of cigarettes comprises three superimposed layers and is formed by superimposing the layers, and when the hopper comprises, for example, three groups of three outlets each, the supply device moves forward in steps to position, at each stop, nine pockets beneath the output end of the hopper and aligned with the nine outlets. In this case, the output end of the hopper has nine push members, which are activated simultaneously to transfer, at each stop of the supply device, a layer of cigarettes into each of the nine pockets facing the respective push members. 
     The push members are so arranged that each of three first push members feeds a respective bottom layer into each of the three facing pockets; each of three second push members feeds a respective intermediate layer into each of the three facing pockets; and each of three third push members feeds a respective top layer into each of the three facing pockets. Since a complete group of cigarettes is formed inside a respective pocket in the course of three successive steps of the supply device, each pocket is therefore positioned, in the course of said steps, at the three outlets defining the same group of outlets. 
     When each group of cigarettes comprises two or more superimposed layers and is formed in one go at a respective outlet, and when the hopper comprises at least two outlets, which may be located over the same cigarette group conveyor line or over respective parallel lines, the supply device moves forward in steps to position, at each stop, two pockets beneath the output end of the hopper and aligned with the two outlets. In this case, the output end of the hopper has two push members, which are activated to transfer, at each stop of the supply device, a group of cigarettes into each of the two facing pockets. 
     A major drawback of both the above known forming devices lies in incomplete groups of cigarettes issuing from the hopper—and which must therefore be rejected—whenever the flow of cigarettes along even only one channel of any one of the outlets is cut off by the presence, for example, of a cigarette positioned crosswise over the inlet of the channel. 
     To eliminate the above drawback, known forming devices of the above type normally comprise a stop signal emitter, which provides for total stoppage of the packing machine in response to a signal indicating no flow of cigarettes along even only one of the supply channels. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a method of forming groups of cigarettes, designed to eliminate the aforementioned drawbacks. 
     In particular, it is an object of the present invention to provide a method of forming groups of cigarettes, whereby stoppage of the outflow of cigarettes from an outlet of the hopper does not result in the formation of incomplete groups of cigarettes, let alone in total stoppage of the packing machine. 
     It is a further object of the present invention to provide a method of forming groups of cigarettes, which provides, if necessary, for reducing the output of a cigarette packing machine implementing the method. 
     According to the present invention, there is provided a method of forming groups of cigarettes on a cigarette packing machine; the packing machine comprising a hopper for supplying cigarettes; the hopper comprising at least two groups of outlets; each group of outlets comprising a number of outlets ranging between one and a number equal to the number of layers of cigarettes in each group of cigarettes; and the outlets in each group of outlets participating in forming a respective said group of cigarettes; the method being characterized by comprising the step of simultaneously intercepting respective streams of cigarettes issuing from all the outlets in a said group of outlets in response to a control signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Two non-limiting embodiments of the invention will be described by way of example with reference to the accompanying drawings, in which: 
     FIG. 1 shows a schematic front view, with parts removed for clarity, of a preferred embodiment of the forming device according to the present invention; 
     FIG. 2 shows a larger-scale, partially sectioned view in perspective of a detail in FIG. 1; 
     FIG. 3 shows a larger-scale view of a further detail in FIG. 1; 
     FIG. 4 shows a section, with parts removed for clarity, along line IV—IV in FIG. 2; 
     FIG. 5 shows the FIG. 2 detail in successive operating positions; 
     FIG. 6 shows a section along line VI—VI in FIG. 1; 
     FIG. 7 shows the same view as in FIG. 1 of a further embodiment of the forming device according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Number  1  in FIG. 1 indicates as a whole a device for simultaneously forming at least two groups  2  (FIG. 3) of cigarettes  3  (in the example shown, three groups  2  of cigarettes  3 ) on a cigarette packing machine  4 . 
     Forming device  1  comprises a supply device  5  for feeding a succession of groups  2  to a packing line (not shown) of packing machine  4 . Each group  2  forms the content of a packet (not shown) of cigarettes, and is defined by at least one layer of cigarettes, and preferably by a number of superimposed layers of cigarettes  3 . In particular, in the FIG. 3 embodiment, each group  2  comprises three superimposed layers  6  indicated  6   a ,  6   b  and  6   c.    
     Supply device  5  comprises two pulleys  7 —one of which is powered—fitted to a fixed frame  8  so as to rotate in steps about respective axes parallel to each other and perpendicular to the FIG. 1 plane. In the example embodiment shown, device  5  also comprises a single conveyor belt  9  looped about pulleys  7  and having a number of pockets  10  equally spaced along belt  9  and each for receiving a respective group  2 . Pulleys  7  are rotated anticlockwise, and the pockets  10  along a substantially horizontal top conveying branch of belt  9  are fed in a direction  11  and along a substantially horizontal supply path P. 
     In variations not shown, pulleys  7  support a number of belts  9  parallel with one another and each having a respective succession of pockets  10 . 
     Forming device  1  also comprises a hopper  12  located over, and set back with respect to, device  5 , and which forms the end portion of a unit  13  for supplying cigarettes  3 . Hopper  12  comprises an output end  14  having nine outlets  15  divided into three groups indicated  16 ,  17 ,  18 , and each group is defined by the three outlets  15  responsible for forming the same group  2  of cigarettes  3 . Outlets  15  may be arranged with any spacing over belt  9 , and belt  9  itself operated in steps of any length, providing, as in the example shown, each outlet  15  faces a respective pocket  10  at each stop of belt  9 , and, at each stop, each pocket  10  is positioned beneath a different outlet  15  of the relative group  16 ,  17 ,  18  until group  2  is completed. 
     In the FIG. 1 embodiment, outlets  15  are so arranged along path P that, at each stop of belt  9 , each of the first three outlets  15  feeds a bottom layer  6   a  of cigarettes  3  into a respective pocket  10 ; and, at the same time, each of the second three outlets  15  feeds an intermediate layer  6   b  of cigarettes  3  into a respective pocket  10 , and each of the third three outlets  15  feeds a top layer  6   c  of cigarettes  3  into a respective pocket  10 . 
     In alternative embodiments not shown, hopper  12  comprises a number of outlets  15  equal to any further multiple of three, and the three outlets  15  defining the same group  16 - 18  are arranged along path P in a different order from that shown in FIG. 1, e.g. are adjacent to one another. It should also be pointed out that, depending on the number of layers  6  in each group  2  of cigarettes  3 , the outlets  15  of hopper  12  are divided into groups of outlets  15 , each comprising a number of outlets  15  equal to the number of layers  6  in the relative group  2  of cigarettes  3 . 
     Each outlet  15  is divided by substantially vertical partitions into a number of channels  19  equal in number to the cigarettes  3  in relative layer  6 , and along which cigarettes  3  travel in a direction substantially crosswise to direction  11  and to the respective longitudinal axes of cigarettes  3 . 
     With reference to FIGS. 2 and 4, hopper  12  comprises three fixed horizontal plates  20  located beneath hopper  12  to support the cigarettes  3  traveling along channels  19  of the first three outlets  15 , of the second three outlets  15 , and of the third three outlets  15  respectively. The respective top surfaces  21  of plates  20  are located at increasing levels differing from one another by an amount substantially equal to the diameter of a cigarette  3 , and, together with respective outlets  15 , define respective horizontal gaps  22  of a height approximately equal to but no less than the diameter of a cigarette  3  (FIG.  4 ). It should be pointed out that surface  21  of plate  20  relative to the first three outlets  15  is coplanar with the bottom wall of each pocket  10 . 
     Each outlet  15  has two parallel guides  23 , which are located on opposite sides of outlet  15  in direction  11 , extend parallel to a horizontal direction  24  crosswise to direction  11 , are connected integrally to relative plate  20 , and project from the opposite edge of plate  20  to that facing belt  9 . Each guide  23  has a bottom longitudinal groove  25  and a top longitudinal groove  26 , which extend parallel to direction  24  and are formed along the edge of guide  23  facing the other guide  23 . 
     The two grooves  25  house in sliding manner a push member  27 , which is defined by a substantially rectangular plate—two opposite longitudinal edges of which are engaged in sliding manner inside respective grooves  25 —and is moved by an actuating cylinder  28  normally common to all of push members  27 , which are therefore moved simultaneously between a rest position (FIGS. 5 b  and  5   d ) in which push member  27  is located substantially outside relative gap  22 , and a work position (FIGS. 5 a  and  5   c ) in which push member  27  is located inside relative gap  22 . The top surface of member  27  has a number of grooves  29  equal in number to the channels  19  of respective outlet  15  and parallel to direction  24 . When member  27  is in the work position, each groove  29  is positioned facing the outlet of a respective channel  19  to receive a respective cigarette  3 . 
     The two grooves  26  of guides  23  of each outlet  15  house in sliding manner an intercepting member  30  comprising a substantially rectangular plate  31 , the opposite longitudinal edges of which engage in sliding manner respective grooves  26 . Member  30  also comprises a connecting device  32  for connecting plate  31  and member  27  to each other so as to move plate  31 , together with member  27 , between a rest position (FIGS. 5 a  and  5   b ) in which plate  31  is substantially outside relative gap  22 , and a work position (FIGS. 5 c  and  5   d ) in which plate  31  engages relative gap  22 . 
     As shown in FIG. 4, the total height of member  27  and plate  31  is approximately equal to but no greater than the diameter of a cigarette  3 , and is therefore less than the height of relative gap  22 . 
     As shown in FIG. 5, connecting device  32  comprises a tubular guide body  33  extending upwards from plate  31  and coaxial with a through hole  34  formed through plate  31 . Connecting device  32  also comprises a pin  35 , a head  36  of which normally cooperates, by means of a spring  37 , with a top free surface of tubular body  33 , and an end portion  38  of which, at the opposite end to head  36 , projects from the bottom of plate  31  to engage a through hole  39  in member  27  when head  36  is positioned contacting the top end of tubular body  33 . Pin  35  is moved in opposition to respective spring  37  by an actuating unit  40  comprising two electromagnets  41  and  42 , which are coaxial with pin  35  and face head  36  when plate  31  is in the work position and rest position respectively. Electromagnets  41  and  42  are energized selectively by a central control unit  43 , which is normally common to all of intercepting members  30  and operates in response to a signal supplied to central control unit  43  by any one of control devices  44 , each relative to a respective channel  19  of outlet  15 . 
     Each plate  31  is provided with a ball lock device  45  for preventing accidental translation of plate  31  in direction  24  when plate  31  is in the work or rest position. Device  45  comprises two balls  46 , each of which—by means of a respective spring  47  parallel to direction  11  and supported by respective guide  23 , and when plate  31  is in the rest or work position—selectively engages two respective cavities  48  and  49  formed along a respective longitudinal edge of plate  31 . 
     Operation of forming device  1  will be described with reference to FIG.  5 . 
     In FIG. 5 a , forming device  1  is shown in the steady operating condition, in which intercepting members  30  are set to the rest position and disconnected from respective push members  27 ; each electromagnet  42  is energized by central control unit  43  to keep respective pin  35  raised in opposition to respective spring  37  and therefore withdrawn from hole  39  in respective push member  27 , which, at each step of belt  9 , transfers a respective layer  6  of cigarettes  3  into the facing pocket  10  without drawing along respective intercepting member  30 , which is kept in the rest position by respective balls  46  engaging respective cavities  48 . 
     In the steady operating condition, each step of supply device  5  corresponds to the formation of three complete groups  2  of cigarettes  3 , which each comprise three superimposed layers  6  and are housed inside the three pockets  10  issuing, at each step, from beneath hopper  12 . As a complete group  2  of cigarettes  3  is formed inside respective pocket  10  in the course of three successive steps of supply device  5 , each pocket  10 , in the course of said steps, is therefore positioned at three respective outlets  15  forming the same group  16 - 18  of outlets  15 . Upon control device  44  of any one of channels  19  of an outlet  15  supplying central control unit  43  with a signal indicating clogging of, or a shortage of cigarettes  3  in, channel  19 , central control unit  43  simultaneously activates the intercepting members  30  of the outlet  15  comprising the malfunctioning channel  19  and of all the outlets  15  forming part of the same group  16 - 18  as the intercepted outlet  15 , thus preventing the formation of incomplete groups  2  of cigarettes  3  which would have to be rejected, and also enabling servicing of the malfunctioning channel  19  without interrupting operation of forming device  1 . 
     The way in which intercepting members  30  of the three outlets  15  in each group  16 - 18  of outlets  15  are moved from the rest to the work position will now be described with reference to FIGS. 5 b - 5   d.    
     With reference to FIG. 5 b , central control unit  43  deactivates electromagnets  42  so that respective pins  35 , by means of respective springs  37 , engage respective holes  39  in respective push members  27 ; at which point (FIG. 5 c ), the intercepting members  30  of the three outlets  15  in question are moved simultaneously by actuating cylinder  28 , and together with respective push members  27 , into the work position. As each intercepting member  30  reaches the work position (FIG. 5 c ), balls  46  of respective lock device  45  engage cavities  49  in respective plate  31 , and central control unit  43  energizes respective electromagnet  41  to release respective pin  35  from respective hole  39  (FIG. 5 d ), so that, whereas the three intercepting members  30  remain in the work position cutting off supply of respective cigarettes  3  to the three outlets  15  in question, the three associated push members  27  are released from respective intercepting members  30  to allow group operation of push members  27 , which, at each operating cycle, are all moved simultaneously by cylinder  28  between the respective rest and work positions. 
     Forming device  1  also operates as described above in response to an external signal supplied to central control unit  43  to indicate, for example, malfunctioning of the packing line (not shown) downstream from forming device  1 ; in which case, considerable advantage is to be gained by operating forming device  1  at reduced capacity, i.e. with only six or three outlets  15 . Depending on the signal received, central control unit  43  therefore provides for simultaneously closing the outlets  15  of one or two groups  16 - 18  of outlets  15 . 
     When the outlets  15  of one or more groups  16 - 18  are intercepted, supply of the packing material for all the unformed groups  2  of cigarettes  3  not supplied to the packing line (not shown) is obviously also cut off. 
     The FIG. 7 variation shows a forming device  50  for forming groups  2  of cigarettes  3 , and which forms part of a packing machine  51  for forming groups  2  of cigarettes  3  comprising three superimposed layers  6 . In the case of forming device  50 , each group  2  of cigarettes  3  is formed in one go at a respective outlet  15  of a hopper  52  which, in this case, comprises two groups  16 ,  17  of outlets  15 , which groups are both located over the same line for conveying groups  2  of cigarettes  3 , and are each defined by one outlet  15 . 
     In the steady operating condition, each step of supply device  5  corresponds to the formation of two complete groups  2  of cigarettes  3  housed inside the two pockets  10  issuing, at each step, from beneath hopper  12 . Upon control device  44  of any one of channels  19  of an outlet  15  supplying central control unit  43  with a signal indicating clogging of, or a shortage of cigarettes  3  in, channel  19 , central control unit  43  activates the intercepting member  30  of the outlet  15  comprising the malfunctioning channel  19 , thus enabling servicing of the malfunctioning channel  19  without interrupting operation of packing machine  51  as a whole. 
     As on packing machine  4 , emission of a stop signal by central control unit  43  to close one or more outlets  15  may be operator-controlled to reduce the output of packing machine  51 . 
     In alternative embodiments not shown, outlets  15  may obviously be more than two in number, and may be arranged over a number of parallel lines for conveying groups  2  of cigarettes  3 .