Abstract:
Cigarettes are transferred in batches adopting a procedure that includes the steps of feeding loose cigarettes en masse into a hopper with a back wall and two side walls delimiting a top inlet and a bottom outlet, also a shutter by which the bottom outlet is opened or closed, and actively varying the geometry of the side walls so that the internal volume of the hopper is adapted to accommodate the quantity of cigarettes admitted through the inlet, by means of an actuator mechanism connected to the side walls. Thus, it becomes possible to monitor and control both the rate at which the cigarettes flow into the hopper, and the pressure to which the single cigarettes are subjected while occupying the hopper and during the process of filling a tray.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a device and to a procedure for the transfer of tobacco products in batches.  
         [0002]     The invention finds application to advantage in complete manufacturing lines for tobacco products, such as cigars, cigarettes and filter tips, and in particular for cigarettes; one typical instance, by way of example, would be the operation of directing the tobacco products in question from a maker to a packer or other wrapping machine.  
         [0003]     In accordance with one conventional method of this type, cigarettes emerging from the maker are ordered in containers, known as trays, which will be stored in readiness before being emptied at an infeed station of the packer.  
         [0004]     The single trays are filled by means of a hopper presenting a vertical back wall, and two fixed side walls extending divergently from top to bottom.  
         [0005]     The aforementioned walls combine to delimit a top inlet opening in communication with a conveyor, on which tobacco products advance in a continuous flow toward the hopper, and a bottom discharge opening closed off by a movable shutter.  
         [0006]     The hopper is emptied cyclically, whilst the flow through the inlet opening is continuous. The hopper is filled by closing off the bottom discharge opening and allowing the cigarettes received from the conveyor to accumulate inside.  
         [0007]     To fill a tray, the hopper bottom is opened for a duration sufficient to allow the cigarettes to pass into the tray beneath, the tray also being lowered by degrees as the cigarettes are taken up.  
         [0008]     The trays have to be filled at relatively high speed in order to keep up with the fast production tempo of the cigarette maker, and at the same time with special care, so that the cigarettes will not lose their ordered arrangement and suffer damage.  
         [0009]     Whilst the cigarettes flow substantially non-stop from the conveyor into the hopper, the flow is not uniformly constant. Consequently, it often happens that the rate of flow is too high, with the result that the cigarettes will be compressed excessively one against another or against the hopper walls and their integrity compromised, for example through tobacco being shed from the cut ends.  
         [0010]     Conversely, if the rate of flow drops below an optimum level, then the massed cigarettes will lack compactness and lose their orderly arrangement, possibly assuming incorrect positions one relative to another, for example wrongly oriented, with axes no longer perpendicular to the back wall of the hopper but slightly askew, or even falling into a void and bending and breaking as a result.  
         [0011]     The object of the present invention is to provide a device and a procedure for the batch transfer of tobacco products, such as will ensure that the products are handled with extreme care during the operation of filling the aforementioned trays.  
         [0012]     In particular, the object of the invention is to design a device and a procedure that will allow of accurately monitoring and controlling both the rate at which the cigarettes flow into the hopper, and the pressure acting on the single cigarette while in the hopper and when transferred into a tray.  
         [0013]     A further object of the invention is to provide a device and a procedure for the batch transfer of tobacco products that will be compatible with high speed operation and allow an ordered arrangement of cigarettes massed in large quantities for loading into trays.  
       SUMMARY OF THE INVENTION  
       [0014]     The stated objects are realized according to the present invention in device for the batch transfer of tobacco products of the type comprising a hopper furnished with a back wall and two side walls combining to delimit a top inlet opening through which tobacco products are admitted, and a bottom opening from which the tobacco products are discharged, also a shutter by which the bottom opening is opened or closed; the device disclosed further comprises a motion-inducing mechanism connected to the side walls, such as will actively vary the geometry of the side walls in order to adapt the internal volume of the hopper to the quantity of tobacco products admitted through the top opening.  
         [0015]     The aforementioned objects are realized similarly in a procedure for the batch transfer of tobacco products that involves feeding a flow of such products into a hopper furnished with a back wall and two side walls combining to delimit a top inlet opening, and a bottom opening from which the tobacco products are discharged, also a shutter by which the bottom opening is opened or closed, and includes the step of actively varying the geometry of the side walls and the internal volume of the hopper, according to the quantity of tobacco products admitted, by means of a motion-inducing mechanism linked to the side walls. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:  
         [0017]      FIG. 1  is a front elevation view of a device in accordance with the present invention, illustrated in a first operating configuration and with certain parts cut away better to reveal others;  
         [0018]      FIG. 2  shows the device of  FIG. 1  in a second operating condition;  
         [0019]      FIGS. 3, 4 ,  5  and  6  show the device of  FIGS. 1 and 2  in successive steps during the operation of filling a container.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     Referring to  FIGS. 3, 4 ,  5  and  6 , numeral  1  denotes a device, in its entirety, for transferring tobacco products  2  in batches, or lots, by means of containers  3  known commonly as trays, from a first processing unit  4  to a second processing unit  5 , and in particular from a cigarette maker  4  to a cigarette packer  5 . Both of the units  4  and  5  in question are of familiar embodiment and therefore illustrated only schematically.  
         [0021]     The device  1  comprises a main conveyor  6  by which tobacco products, in this instance cigarettes  2 , are carried from the cigarette maker  4  toward the packer  5  along a predetermined direction X; the conveyor  6  operates in conjunction with a unit for management of the containers  3 , each of which is able to hold a plurality of cigarettes  2  arranged in ordered alignment.  
         [0022]     The container management unit is neither shown nor described, but could be of the type disclosed in (patent application no EP 06116470.3 or application no EP 06116480.2, both filed in the name of the present applicant.  
         [0023]     With reference in particular to  FIG. 4 , each container  3  presents a rectangular bottom  7 , of which the shorter side is matched substantially to the length of a single cigarette  2  and the longer side compasses several tens of the cigarettes  2  disposed side by side, also a main wall  8 , likewise rectangular, set at right angles to the bottom  7  and joined along one longer side to a corresponding longer side of the bottom  7 . The cigarettes  2  lie with one end offered in contact to the main wall  8 , which presents a shorter side compassing several tens of cigarettes  2  disposed side by side; thus, the container  3  will hold several thousands of cigarettes, arranged quincuncially. The container  3  also presents two mutually opposed and parallel side walls  9  perpendicular to the bottom  7  and to the main wall  8 , combining to delimit an opening  10  on the side opposite from the bottom  7 , through which the container  3  can be filled and emptied, and an auxiliary opening  11  on the side opposite from the main wall  8 .  
         [0024]     In addition, the main conveyor  6  presents an opening  12  located intermediately along its length, directly above and communicating with a hopper denoted  13 .  
         [0025]     In the preferred embodiment illustrated, the main conveyor  6  comprises a first belt  14  looped around pulleys  15 , extending between the cigarette maker  4  and the hopper  13  and presenting a top branch  16  on which cigarettes  2  emerging from the maker  4  are carried, lying side by side.  
         [0026]     A second belt  17 , looped over relative pulleys  18  and aligned in the same plane as that occupied by the first belt  14 , extends from the hopper  13  to the cigarette packer  5  and presents a top branch  19  carrying cigarettes  2  about to enter the packer  5 . The first belt  14  and the second belt  17  present respective ends  20  and  21  positioned facing one another and combining to delimit the intermediate opening  12  aforementioned.  
         [0027]     The hopper  13  comprises a back wall  22  and two side walls  23  delimiting a top inlet opening  24   a  aligned with the opening  12  in the conveyor  6 .  
         [0028]     The side walls  23  are mutually divergent, extending from the ends  20  and  21  of the belts  14  and  17  and spreading to a distance marginally less than the width of one container  3 .  
         [0029]     Each side wall  23  is also of width approximately equal to the length of one cigarette  2 , so that the hopper  13  presents a bottom discharge opening  24   b  substantially identical in terms of outline and dimensions to the bottom  7  of the container  3 . This same opening  24   b  can be opened or closed by a shutter  25  of conventional embodiment, comprising a plurality of retaining bars  25   a  set perpendicular to the back wall  22  and arrayed side by side. The bars  25   a  are capable of movement between an open position ( FIGS. 1, 3 ,  4  and  6 ), in which the space between any two adjacent bars is sufficient to admit one cigarette  2 , and a closed position ( FIGS. 2 and 5 ) in which the bars  25   a  are drawn into close order by pivoting on respective offset axes and the cigarettes  2  are unable to pass between them.  
         [0030]     More exactly, with reference to  FIGS. 3 and 4 , the intermediate opening  12  of the conveyor  6  and the top opening  24   a  of the hopper  13  are linked via a duct  26  delimited by a pair of mutually opposed vertical walls  27  mounted to a fixed frame  28  of the device  1 .  
         [0031]     Numeral  29  denotes a support element located next to the hopper  13  and driven by a relative motor  30 , shown schematically, of which the function is to carry and position a single container  3  during the filling cycle (FIGS.  4  to  6 ).  
         [0032]     The support element  29  is traversable vertically between a first position ( FIG. 4 ) of proximity to the bottom opening  24   b  of the hopper  13  and a second position ( FIG. 6 ) distanced from the bottom opening  24   b , thus allowing the container  3  to fill up gradually during its descent ( FIG. 5 ), as will be explained later in the specification.  
         [0033]     With the cigarette maker  4 , the packer  5  and the device  1  in operation, cigarettes  2  emerging from the packer  4  and advancing along the conveyor  6  gravitate into the hopper  13 , which is closed at the bottom by the shutter  25  and will therefore fill to the point where further cigarettes  2  begin rolling over the cigarettes  2  occupying the duct  26  and pass beyond, advancing toward the packer  5 . In normal operation, accordingly, part of the total flow of cigarettes  2  will fill the hopper  13  and the trays  3 , and part will find its way directly into the packer  5 .  
         [0034]     Empty containers  3  are brought to the hopper  13  one at a time by the aforementioned management unit (not illustrated) in readiness for filling. To this end, the container  3  is offered to the hopper  13  with the top opening  10  directed upwards, the auxiliary opening  11  facing the hopper  13 , and the bottom  7  beneath the bottom discharge opening  24   b , so that the hopper  13  is effectively positioned internally of the container  3  ( FIG. 4 ).  
         [0035]     Next, the hopper  13  is emptied by shifting the bars  25   a  of the shutter  25  to the open position so as to release the cigarettes  2 , which drop through the bottom opening  24   b  onto the bottom  7  of the container  3 ; at the same time, the container  3  is lowered gradually to free more space ( FIG. 5 ).  
         [0036]     When the container  3  is full, the bars  25   a  of the shutter  25  return to the closed position ( FIG. 6 ) and the container  3  is directed toward a storage location while the hopper  13 , still full, continues to receive cigarettes  2  from the conveyor  6 . Thus, the hopper  13  discharges cyclically whereas the incoming flow is continuous.  
         [0037]     Also forming part of the device  1  is a motion-inducing mechanism  31  linked to the side walls  23  of the hopper  13 , such as will actively vary the geometry of the selfsame side walls  23 , and thus reproportion the internal volume of the hopper  13 , according to the quantity of cigarettes  2  admitted.  
         [0038]     As shown in  FIGS. 1 and 2 , the motion-inducing mechanism  31  comprises at least one sensor  32  able to monitor a parameter indicating the quantity of tobacco products  2  admitted to the hopper  13 , an actuator  33  connected to the side walls  23 , which are deformable, and a control unit  34  to which both the sensor  32  and the actuator  33  are connected. The control unit  34  receives a signal S from the sensor  32  indicating the quantity of tobacco products  2  entering the hopper  13  and generates a signal C 1  by which the actuator  33  is piloted to vary the geometry of the side walls  23 .  
         [0039]     The variation in internal volume of the hopper  13  must be proportioned so as to avoid compression and degradation of the cigarettes  2 , while at the same time ensuring the flow remains suitably compact, so that the cigarettes  2  do not lose their ordered alignment.  
         [0040]     As illustrated in  FIGS. 1, 5  and  6 , to ensure balanced pressure and compactness in the flow of cigarettes  2  admitted to the hopper  13 , the control unit  34  is also connected to the motor  30  of the support element  29  in such a way as to vary the rate of descent Vd of the selfsame element  29  ( FIG. 5 ) in response to the signal S received from the sensor  32 , by generating a respective control signal denoted C 2  ( FIG. 1 ).  
         [0041]     In a preferred embodiment, the sensor  32  will be located near the conveyor  6  along the predetermined direction X followed by the cigarettes  2 , above the top opening  24   a  of the hopper  13 , so as to measure the rate of the flow.  
         [0042]     In particular, the sensor  32  is a feeler placed to measure the depth Sp of the flow of cigarettes  2  advancing along the conveyor  6  ( FIG. 3 ).  
         [0043]     The feeler  32  comprises a finger  35  of which a first end  35   a  is coupled to the spindle  36  of a potentiometer such as will pick up any angular movement of a floating second end  35   b.    
         [0044]     The second end  35   b  appears substantially flat when seen in cross section, and is thus able to ride on the cigarettes  2  without damaging them.  
         [0045]     The potentiometer is mounted above the conveyor  6  and over a zone  37  occupied by the advancing flow of cigarettes  2 , with the spindle  36  set at right angles to the back wall  22  of the hopper  13 . The finger  35  is capable of movement between a first position, in which the second end  35   b  encroaches on the zone  37  occupied by the cigarettes  2 , and a second position in which it is caused by a rise in level of the flow of cigarettes  2  to rotate through an angle α ( FIG. 3 ) determined by the depth Sp of the cigarettes  2  present on the conveyor  6  at the intermediate opening  12 .  
         [0046]     In the preferred embodiment illustrated in the accompanying drawings, each of the side walls  23  of the hopper  13  comprises a flexible leaf  38 . A first end  38   a  of the leaf  38  is inserted slidably in a terminal portion  39  associated pivotably with the fixed frame  28  of the device  1  by way of an axis Y of rotation located near the top inlet opening  24   a . The leaf  38  also presents a second end  38   b  associated pivotably with the fixed frame  28  of the device  1  by way of a further axis W located near the bottom discharge opening  24   b.    
         [0047]     The actuator  33  comprises a pair of levers  40  flanking the hopper  13 , each with a first end  40   a  hinged to the frame  28  and a second end  40   b  linked to a corresponding flexible leaf  38 .  
         [0048]     The first end  40   a  of each lever  40  is coupled to a pivot  41  turning on an axis Z located alongside the axis Y of rotation of the terminal portion  39  aforementioned. The second end  40   b  of the lever  40  is linked to a middle area  42  of the respective leaf  38  by way of a connecting rod  43  coupled pivotably to the lever  40  and attached hingedly to a lug  44  associated rigidly with the leaf  38 .  
         [0049]     Each of the levers  40  is connected to a motor  45  and rendered capable thus of angular movement on the pivot  41  at its first end  40   a.    
         [0050]     The motor  45  will consist preferably in a double acting pneumatic or fluid power cylinder  46  mounted horizontally near to the inlet opening  24   a  of the hopper  13  ( FIGS. 1 and 2 ). The cylinder  46  has a central body  47  slidably accommodating two mutually opposed rods  48  capable of movement in respective horizontal directions.  
         [0051]     Each rod  48  carries a pin  49  engaging a socket  50  afforded by the first end  40   a  of the corresponding lever  40  and distanced from the rotational axis Z of the pivot  41 . Thus, a linear displacement of the rod  48  produces an angular movement of the lever  40  which, by way of the connecting rod  43 , will either push or pull on the leaf  38  at the middle area  42  and cause it to arch.  
         [0052]     More exactly, with the two rods  48  in a partially extended position, the leaves  38  remain undeformed and straight ( FIG. 1 ). Retracting the two rods  48  from the aforementioned partially extended position back into the central body  47 , the levers  40  will swing in opposite directions and spread the two second ends  40   b  apart, thus arching the leaves  38  outward and increasing the volume of the space enclosed by the hopper  13  ( FIG. 2 ). Conversely, extending the rods  48  beyond the partially extended position will have the effect of drawing the second ends  40   b  together, causing the leaves  38  to arch inward and reducing the volume of the space enclosed by the hopper  13  (a configuration not illustrated in the drawings).  
         [0053]     There now follows a description of a preferred through not exclusive transfer procedure employing the device  1  disclosed.  
         [0054]     In operation, with the hopper  13  filling up, the control unit  34  is programmed to position the two side walls  23  according to a prescribed law of deformation “Ld” that corresponds to a reference flow rate “Pr” of the cigarettes  2  advancing on the conveyor  6 . At the same time, the control unit  34  also monitors the effective flow rate “Pe” by way of the sensor  32 , comparing this value with the reference value “Pr” and, should the effective rate “Pe” differ from the reference rate “Pr”, responds by adjusting the law of deformation “Ld”.  
         [0055]     More exactly, from the moment when the bottom of the hopper  13  is closed off by the shutter  25 , the cigarettes  2  begin to accumulate, rising ultimately to the level of the intermediate opening  12 . During this stage, the control unit  34  is programmed to pilot the operation of the actuator  33  in such a way that the volume internally of the hopper  13  will be increased in accordance with the prescribed law of deformation “Ld” which, for example, induces a linear variation in the deflection Fr ( FIG. 2 ) of the flexible leaves  38  with a time component expressed as “Ld: Fr=at +b”, where “t” is time and “a” and “b” are constants, the deflection in this instance being characterized by a constant rate of deformation equal to “V Fr =a”.  
         [0056]     The law “Ld” governing the increase in volume is precomputed so that the reference flow rate “Pr” of the advancing cigarettes  2  will be sensed by the feeler  32  as constant, or rather, the flow passing beneath the feeler  32  will present a constant reference depth “Sp r ”.  
         [0057]     If the effective rate of flow “Pe” sensed by the feeler  32 , or the effective depth “Sp e ”, is not at variance with the reference value “Pr”, the control unit  34  will apply no correction to the law “Ld” governing the increase in volume.  
         [0058]     If the effective rate of flow “Pe” sensed by the feeler is greater than the reference rate “Pr”, or the effective depth “Sp e ” is greater than the reference depth “Sp r ,” the control unit  34  will alter the law “Ld” governing the increase in volume in such a way, for example, as to speed up the rate at which the side walls  23  are deformed.  
         [0059]     If the effective rate of flow “Pe” sensed by the feeler is less than the reference rate “Pr”, or the effective depth “Sp e ” is less than the reference depth “Sp r ,” the control unit  34  will alter the law “Ld” governing the increase in volume in such a way as to slow the rate at which the side walls  23  are deformed, for example, or to leave the walls  23  undeformed, or indeed to reduce the volume of the hopper  13  by causing the walls  23  to flex inwards.  
         [0060]     The control unit  34  also governs the rate “Vd” at which the support element  29  descends during the step of emptying the hopper  13  and filling the container  3 . The container  3  is lowered according to a prescribed law of motion “Lm” that corresponds to the reference flow rate “Pr” of the cigarettes  2  advancing on the conveyor  6 . At the same time, the control unit  34  senses the effective flow rate “Pe” by way of the sensor  32 , comparing this value with the reference value “Pr”, and should the effective rate “Pe” differ from the reference rate “Pr”, responds by adjusting the law of motion “Lm”.  
         [0061]     In detail, to fill a container  3 , the shutter  25  opens and the cigarettes  2  begin to drop into the container  3 . During this step, the control unit  34  is programmed to pilot the speed of the motor  30  driving the support element  29  so that the element will descend subject to the predetermined law of motion “Lm” which, for example, induces a downward movement of the container  3  according to a law expressed as “Lm: S=ct+d”, where “t” is time and “c” and “d” are constants, which results in a rate of descent equal to “Vd=c”.  
         [0062]     The law “Lm” governing the rate of descent is precomputed so that the reference flow rate “Pr” of the advancing cigarettes  2  will be sensed by the feeler  32  as constant, or rather, the flow passing beneath the feeler  32  will present a constant reference depth “Sp r ”.  
         [0063]     If the effective rate of flow “Pe” sensed by the feeler  32 , or the effective depth “Sp e ”, is not at variance with the reference value “Pr”, the control unit  34  will apply no correction to the law “Lm” governing the rate of descent.  
         [0064]     If the effective rate of flow “Pe” sensed by the feeler is greater than the reference rate “Pr”, or the effective depth “Sp e ” is greater than the reference depth “Sp r ,” the control unit  34  will alter the law of motion “Lm” in such a way as to increase the rate Vd at which the container  3  descends.  
         [0065]     If the effective rate of flow “Pe” sensed by the feeler is less than the reference rate “Pr”, or the effective depth “Sp e ” is less than the reference depth “Sp r ,”, the control unit  34  will alter the law of motion “Lm” in such a way as to reduce the rate Vd at which the container  3  descends.  
         [0066]     The function of monitoring the rate of descent Vd can also be performed simultaneously with that of monitoring the deformation of the side walls  23 , applying a control logic that is more complex and not described here.  
         [0067]     In any event, all of the monitoring and control operations are intended primarily to ensure that the pressure exerted on each cigarette  2  by the other cigarettes and by the walls of the hopper  13  remains constant, so that the cigarettes will not be crushed and damaged.  
         [0068]     Moreover, these same operations ensure that the cigarettes  2  can be kept in their proper orderly alignment, and prevented from assuming positions with axes no longer perpendicular to the back wall of the hopper, but slightly askew and at risk of bending or breaking.