Abstract:
A continuous tobacco rod generated by a machine for making tobacco products is separated into reclaimable lengths by a device that comprises a pair of tension rollers designed to exert a pulling force on the rod, also a pair of brake rollers operating upstream of the tension rollers and serving to offer a measure of resistance to the action of the tension rollers; as a result of the interaction between the tension rollers and the brake rollers, the portion of the continuous rod extending between them is forced to break by tearing apart.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a device for separating at least one rod of forming material as used in manufacturing tobacco products, applicable in particular to a machine by which such products are made and reflecting the prior art as recited in claim  1 .  
           [0002]    The invention relates also to a method by which at least one continuous rod of forming material for tobacco products is separated into a plurality of reclaimable lengths, implementing steps reflecting the prior art as recited in claim  22 .  
           [0003]    The invention finds application particularly in the field of manufacturing tobacco products, namely cigarettes, cigars and the like, where use is made of machines equipped with a unit serving to fashion a forming material into at least one continuous rod, or tobacco rod, and a cutter device by which the newly formed continuous rod is divided into a succession of discrete portions each destined to become a respective tobacco product.  
           [0004]    In conventional machines used for making tobacco products, such as those described and illustrated in patents IT 1208281 and IT 1171577 and in Italian patent application BO02001A 000604, certain parts of the continuous rod of forming material have to be discarded due to their presenting characteristics incompatible with the manufacture of a marketable tobacco product. The parts destined typically to be discarded will include the initial endmost portion of a continuous rod being formed by the machine, and any intermediate parts happening to display characteristics similar to the end portion.  
           [0005]    Defective parts are eliminated normally by means of a separation or rod breaker device operating between the forming unit and the aforementioned cutter device.  
           [0006]    The separation device, as disclosed in Italian patent IT 1208281, consists generally in a strimmer style cutter, that is to say a rotating head with slender radial or diametral members, driven at high speed by a motor, which is positioned to intercept the advancing continuous rod and divide it up into successive pieces of predetermined length.  
           [0007]    Ordinarily, the separation device operates in conjunction with a cut-off device installed in such machines between the unit forming the continuous rod, and the cutter device. The cut-off device is designed typically to divide the continuous rod into two portions: the first, advancing toward the cutter device downstream of the cut-off device, and the second fed through the machine upstream of the cut-off device.  
           [0008]    The cut-off device is also able to redirect the advancing continuous rod from its original path by directing it toward the separation device. More exactly, this redirection of the continuous rod can be brought about by a diverter element associated with the cut-off device and presenting a curved profile that extends transversely to the direction followed by the continuous rod.  
           [0009]    To effect the change of direction, accordingly, the cut-off device must be shifted in such a way that the diverter element is positioned along the path followed by the advancing continuous rod. As it advances, the continuous rod being formed by the machine will encounter the diverter element and as a result, veer transversely from the original feed path.  
           [0010]    As illustrated in application BO2001A 000604, the continuous rod advanced by the machine is deflected by a diverter element that forms an integral part of the cut-off device. In other words, the cut-off device presents a sharp pointed portion positioned to slice through the advancing continuous rod, and a substantially arcuate portion extending from the sharp portion, functioning as the diverter element, which serves to deflect the continuous rod directly toward a bin serving to collect reject material, or a reclaiming station. Likewise in this situation, the redirection of the continuous rod is brought about by positioning the cut-off device in such a way as will enable the diverter element or arcuate portion to intercept the continuous rod.  
           [0011]    Once the cutting action has been produced by the sharp point of the cut-off device, a portion of the continuous rod not suitable for making into tobacco products will be carried toward the cutter device of the machine, where the unwanted forming material is broken up into a succession of small fragments that fall by gravity directly into a reclaiming station located beneath the cutting area.  
           [0012]    Whilst it is true that devices used to separate continuous rods of forming material for tobacco products are able, as also are the machines used in making such products, to recover a fair quantity of forming material momentarily unsuitable for making into saleable tobacco products, they nonetheless present certain drawbacks and might be improved in a number of ways, with regard mainly to the quality of the forming material collected and reutilized subsequently in the process of fashioning further continuous rods, and as regards the amount of the forming material collected and the reduction in production costs achievable by reclaiming material that would normally be discarded.  
           [0013]    More particularly, the applicant finds that the effect of dividing up continuous rods of forming material into portions employing cutter devices of whatever description (reciprocating and/or rotary), for example those with a rotating head and other such separation devices, is to break up the forming material to a degree that the value of recovering and/or reutilizing it becomes questionable.  
           [0014]    More exactly, when reject portions of continuous rods are subjected to these cutting operations, the tobacco fibers which make up the greater part of the forming material are significantly degraded, in that by being notably shortened, their dimensions will be reduced to the point of disallowing further use.  
           [0015]    Conversely, if the reclaimable continuous rod is not broken up, a laborious unpicking operation is required in order to recover the tobacco fibers contained in the filler, which in turn will signify a considerable expenditure of time and resources tending to impact on overall production costs and, ultimately, on the costs of marketing and selling the product.  
           [0016]    The object of the invention is to overcome the problems identifiable in the prior art by providing a device for separating at least one continuous rod of forming material for tobacco products, and a method by which to divide the separated rod into a plurality of discrete lengths, such as will also preserve the original properties of the forming material.  
           [0017]    Another object of the invention is to achieve a significant reduction in production costs through the recovery of rejected forming material.  
         SUMMARY OF THE INVENTION  
         [0018]    The stated objects are realized according to the present invention in a device for separating at least one continuous rod of forming material for the manufacture of tobacco products, applicable to a machine for making tobacco products affording a feed path along which the continuous rod is caused to advance, and equipped with at least one cut-off device by which the continuous rod is severed and diverted from the feed path, the function of the separation device being to engage the diverted continuous rod of forming material and divide it into a plurality of discrete lengths.  
           [0019]    The device comprises a gripping unit designed to act on the diverted continuous rod by applying forces oriented substantially parallel to the longitudinal dimension of the rod and from opposing directions, so as to generate a tensile stress in the diverted rod that will cause it to break by tearing apart.  
           [0020]    The stated objects are realized similarly in a method according to the invention for separating at least one continuous rod of forming material for tobacco products into a plurality of reclaimable lengths, wherein the separation of the continuous rod involves the step of applying at least two forces oriented parallel to the longitudinal axis of the diverted continuous rod and from opposing directions.  
           [0021]    To advantage, the step of separating the diverted continuous rod into discrete reclaimable lengths is implemented without the use of any cutting action.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:  
         [0023]    [0023]FIG. 1 is a fragmentary schematic side elevation illustrating a machine for making tobacco products, equipped with a device for separating a continuous rod of forming material, embodied in accordance with the present invention;  
         [0024]    [0024]FIG. 2 is an enlarged view of the separation device illustrated in FIG. 1, shown in readiness to interact with the advancing continuous rod;  
         [0025]    [0025]FIG. 3 is an enlarged view of the separation device illustrated in FIG. 1 and FIG. 2, shown interacting with the advancing forming material, which is viewed partly in section.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    With reference to the drawings,  1  denotes a device according to the invention, in its entirety, serving to separate at least one continuous rod of forming material for making tobacco products.  
         [0027]    As discernible from FIG. 1, the separation device  1  is associated with a machine  2  for making tobacco products  3 , typically cigarettes, cigars and the like. More exactly, the machine  2  comprises a forming unit  4  serving to generate at least one continuous rod  5  of forming material from which to fashion the aforementioned tobacco products  3 . The forming unit  4  comprises a conveyor belt  6  looped around pulleys  7  (one only of which is illustrated in FIG. 1) rotatable about respective horizontal and mutually parallel axes  8 .  
         [0028]    The closed loop described by the conveyor belt  6  encompasses a chamber  9  connected to a source of negative pressure (not illustrated) and delimited at the bottom by a wall  10  presenting a plurality of suction holes  11 . As illustrated in FIG. 1, the bottom branch of the looped conveyor belt  6  is breasted in sliding contact with the aforementioned wall  10 . The conveyor belt  6  is able, through the force of suction, to attract and retain particles or fibers of tobacco  12  emerging from a vertical riser duct (not illustrated) positioned below the bottom branch and destined to make up the greater part of the aforementioned forming material, in such a way that the core of the continuous rod  5  can be pre-shaped as the stream of particles is advanced on the belt.  
         [0029]    As illustrated in FIG. 1, the continuous stream of tobacco is directed constantly by the bottom branch of the conveyor belt  6  along a substantially horizontal feed path extending transversely to the axes  8  of rotation of the pulleys  7 .  
         [0030]    Also directed through the forming unit  4  is a strip  13  of paper material coming from a relative feed station of the machine  2 . In particular, the strip  13  is routed in such a manner as to advance in a substantially horizontal plane beneath the conveyor belt  6 , its position maintained by suction generated through a transport belt  14  operating beneath the conveyor belt  6  and constituting part of the forming unit  4 .  
         [0031]    Still referring to FIG. 1, the paper strip  13  is interposed between the conveyor belt  6  and the transport belt  14  and facing directly toward the stream of tobacco. The strip  13  is carried by the transport belt  14  along the aforementioned feed path, denoted X, positioned to receive the tobacco from the bottom branch of the conveyor belt  6 .  
         [0032]    The forming unit  4  also comprises a beam  15  (of conventional embodiment) positioned along the feed path X downstream of the conveyor belt  6 , by which the strip  13  is wrapped around the tobacco to form a continuous rod  5 . More precisely, the beam  15  affords a passage along which the longitudinal edges of the strip  13  are overlapped and glued together. Thus, the continuous rod  5  emerging from the beam  15  appears as a core of tobacco filler enveloped in a cylindrical skin of paper.  
         [0033]    Beyond the forming beam  15  and along the feed path X, in the downstream direction, the continuous rod  5  encounters a cutter device  16  constituting part of the machine  2 , by which it is intercepted intermittently and divided into a succession of portions  17  each destined to become a cigarette.  
         [0034]    The machine  2  further comprises a checker unit  18  interacting with the continuous rod  5  as it leaves the forming beam  15 , and serving to verify that the rod is being correctly formed and/or to detect any defects.  
         [0035]    Also installed on the feed path X, placed between the forming beam  15  and the checker unit  18 , is a cut-off device  19  capable of movement between a position of disengagement, in which the continuous rod  5  emerging from the beam  15  is free to advance as normal along the feed path X, and a position of interference in which the rod  5  is cut through and diverted from the feed path by the device  19 . The cut-off device  19  can come into operation during the start and/or stop cycle of the machine  2 , or in response to a signal from the checker unit  18 . In this situation, it can happen that a portion of the continuous rod  5  remains lodged between the cut-off device  19  and the cutter device  16 , occupying the final part of the feed path X.  
         [0036]    In order to remove this portion of material, the machine  2  can be equipped with suitable ejection means  20  acting directly on the selfsame portion.  
         [0037]    Still in FIG. 1, the separation device  1  is associated functionally with the cut-off device  19  in such a way as to engage the diverted continuous rod  5  and divide it into a plurality of lengths  21  of forming material which are then collected in a reclaiming station  22 .  
         [0038]    More exactly, the separation device  1  comprises a gripping unit  23  of which the function is to act on the diverted continuous rod  5  by applying forces oriented substantially parallel to the longitudinal dimension of the rod and from opposing directions, so as to generate a tensile stress that will cause a break by tearing.  
         [0039]    As illustrated in the accompanying drawings, and more particularly in FIGS. 2 and 3, the gripping unit  23  of the separation device  1  comprises a tensioning unit  24  acting on the continuous rod  5  in such a way as to apply a predetermined pulling force that tends to distance the selfsame rod from the cut-off device  19 . The gripping unit  23  also includes a braking unit  25  associated functionally with the tensioning unit  24 , located between this same unit and the cut-off device  19 . The braking unit  25  likewise acts directly on the diverted continuous rod  5 , operating in conjunction with the tensioning unit  24  so as to induce a tear in the rod  5  at a point between the two units  24  and  25 .  
         [0040]    The tensioning unit  24  comprises at least one pair of tension rollers  26  and  27  positioned to interact tangentially with opposite sides of the continuous rod  5 . Each tension roller  26  and  27  engages the diverted continuous rod  5  by way of a respective contact surface  26   a  and  27   a  presenting a substantially irregular profile, so that the rod  5  will be subjected to the pulling action of the two rollers  26  and  27  at predetermined intervals. More particularly, the contact surface  26   a  and  27   a  of each tension roller  26  and  27  presents at least one pinch portion  26   b  and  27   b  of substantially curved profile proportioned so as to engage the advancing continuous rod  5  directly, and at least one release portion  26   c  and  27   c  extending circumferentially from the pinch portion  26   b  and  27   b  to describe a circular arc of given length, of which the profile is lower than that of the pinch portion and offers no constraint to the advancing rod  5 .  
         [0041]    In the example of the accompanying drawings, each tension roller  26  and  27  presents a corresponding contact surface  26   a  and  27   a  with two diametrically opposed pinch portions  26   b  and  27   b . Each of the two pinch portions  26   b  and  27   b  is located between two release portions  26   c  and  27   c  which in turn occupy diametrically opposed positions on the respective roller  26  and  27 .  
         [0042]    It would also be possible, should requirements so dictate, for the tension rollers  26  and  27  to have more than two pinch portions  26   b  and  27   b  and two release portions  26   c  and  27   c  as in the example of the drawings, without the object of the present invention being altered and/or limited in any way.  
         [0043]    In addition, the tension rollers  26  and  27  are symmetrically identical relative to a longitudinal axis Y of the diverted continuous rod  5 , so that the circular arcs described on either side of the axis Y by the pinch portions  26   b  and  27   b  and/or the release portions  26   c  and  27   c  will be, in practice, mirror images of one another.  
         [0044]    The two tension rollers  26  and  27  can be driven in rotation about their relative axes  28  and  29 , and are interconnected in such a way as to turn at the same peripheral speed. In this way, the matched pinch portions  26   b  and  27   b  will engage the diverted continuous rod  5  simultaneously, whilst the matched release portions  26   c  and  27   c , in combination with the linear velocity of the rod, will determine the duration of the period for which the rod is allowed to advance freely before being engaged by further pinch portions  26   b  and  27   b.    
         [0045]    Similarly, the aforementioned braking unit  25  comprises at least one pair of brake rollers  30  and  31  positioned so as to interact tangentially with opposite sides of the continuous rod  5  by way of respective contact surfaces  30   a  and  31   a  presenting a substantially regular profile. The two brake rollers  30  and  31  are interconnected in operation and rotatable about respective axes  32  and  33  at angular velocities such that their peripheral speed will be essentially the same as the linear velocity of the advancing continuous rod  5 . In short, the brake rollers  30  and  31  do no more than accompany the movement of the diverted continuous rod  5  as it advances toward the tension rollers  26  and  27 .  
         [0046]    As illustrated in the accompanying drawings, the axes of rotation  28 ,  29 ,  32  and  33  of the tension rollers  26  and  27  and the brake rollers  30  and  31  lie substantially parallel. More precisely, the axes  28  and  29  of the tension rollers  26  and  27  occupy a common plane transverse and preferably perpendicular to the longitudinal axis Y of the diverted continuous rod  5 , whilst the axes  32  and  33  of the brake rollers  30  and  31  likewise occupy a common plane transverse to the longitudinal axis Y of the diverted continuous rod  5  and substantially parallel to the plane occupied by the axes  28  and  29  of the tension rollers  26  and  27 .  
         [0047]    The separation device  1  is also equipped with transmission means  34  that can be connected to a drive component  35  installed in the machine  2 , for the purpose of setting the tension rollers  26  and  27  and the brake rollers  30  and  31  in rotation.  
         [0048]    As illustrated in the drawings, the transmission means  34  comprise a first transmission component  36  interposed between one of the brake rollers  30  and  31  and the drive component  35  of the machine  2 . The first transmission component  36  comprises a first wheel  37  associated with the drive component  35  of the machine  2 , a second wheel  38  associated with one of the two rollers of the braking unit  25 , or rather a driving brake roller  30 , and at least one flexible transmission element  39  consisting in a belt, a chain and/or the like, looped around the first and second wheels  37  and  38 .  
         [0049]    The transmission means  34  also comprise a second transmission component  40  associated functionally with the brake rollers  30  and  31  and serving to transmit rotation from the driving brake roller  30  to the other brake roller  31 ., which consequently is driven at the same peripheral speed as the driving roller  30 .  
         [0050]    More particularly, the aforementioned second transmission component  40  is composed of a first and a second rotary transmission element  41  and  42  associated respectively with the driving and driven brake rollers  30  and  31 , projecting radially beyond the circumference of these rollers although not interfering in any way with the movement of the advancing diverted continuous rod  5 . Preferably, the rotary transmission elements  41  and  42  of the second transmission component  40  will consist in respective gears.  
         [0051]    The transmission means  34  also comprise a third transmission component  43  interposed between the braking unit  25  and the tensioning unit  24  and serving thus to transmit rotation to at least one tension roller  26  or  27  of this same Unit. More exactly, the third transmission component  43  is interposed functionally between the driven brake roller  31  and a driving tension roller  26  of which the axis of rotation  28  lies in the same plane as that occupied by the axis  33  of the driven brake roller  31 , the plane in question lying parallel to the longitudinal axis Y of the diverted continuous rod  5 .  
         [0052]    As illustrated in the drawings and in like manner to the first transmission component  34 , the third transmission component  43  comprises a first wheel  44  associated with the driven brake roller  31 , a second wheel  45  associated with the driving tension roller  26 , and at least one flexible transmission element  46  looped around the first wheel  44  and the second wheel  45 . It will be seen in the drawings that the second wheel  45  of the third transmission component  43  is smaller in diameter than the first wheel  44  in such a way that the peripheral speed of the driving tension roller  26  will be greater than that of the driven brake roller  31 .  
         [0053]    A further fourth transmission component  47  of the transmission means  34 , associated functionally with the tension rollers  26  and  27 , serves to transmit rotation from the driving tension roller  26  to the other tension roller  27 , which is driven at the same peripheral speed as the driving roller.  
         [0054]    Like the second transmission component  40 , this fourth transmission component  47  takes the form of a first and a second rotary transmission element  48  and  49  associated respectively with the driving and driven tension rollers  26  and  27  and projecting radially beyond the circumference of these rollers although not interfering with the movement of the advancing diverted continuous rod  5 . Preferably, the rotary transmission elements  48  and  49  of this fourth transmission component  47  will consist in respective gears combining one with another to ensure that the tension rollers  26  and  27  turn at the same peripheral speed.  
         [0055]    The separation device  1 , described prevalently in structural terms thus far, is designed to operate in the following manner.  
         [0056]    Whenever the machine  2  is started and/or stopped, or in response to a control signal from the checker unit  18 , the continuous rod  5  advancing along the feed path X is diverted by the cut-off device  19  toward the separation device  1 .  
         [0057]    On entering the separation device  1 , the diverted continuous rod  5  is guided forward by the brake rollers  30  and  31 , rotating at a peripheral speed equal to the linear velocity of the advancing rod. In effect, when the continuous rod  5  is diverted from its feed path X, the drive component  35  of the machine  2  is activated in such a way as to set in motion the first wheel  37  of the first transmission component  36  connected to the separation device  1 . In rotation, the first wheel  37  drives the flexible transmission element  39 , thereby causing the second wheel  38  of the first transmission component  36  to rotate, and with it the driving brake roller  30 . As the driving brake roller  30  is also linked to the driven brake roller  31  by meshing gears, the driven roller  31  likewise will be set in motion by the driving roller  30  at the same peripheral speed.  
         [0058]    Rotation is transmitted in turn from the driven brake roller  31  to the driving tension roller  26 , by way of the third transmission component  43 . More exactly, given that the first wheel  44  of the third transmission component  43  rotates as one with the driven brake roller  31 , the corresponding flexible transmission element  46  is also set in motion. As a result, this same flexible transmission element  46  in turn will cause the second wheel  45  of the third transmission component  43  to rotate, and with it the associated driving tension roller  26 , in this instance at a peripheral speed greater than that of the brake rollers  30  and  31 .  
         [0059]    Lastly, the driving tension roller  26  is linked by way of the fourth transmission component  47  to the driven tension roller  27 , with both rotating at the same peripheral speed.  
         [0060]    Passing through the tension rollers  26  and  27 , the diverted continuous rod  5  is engaged cyclically by the pinch portions  26   b  and  27   b  of these same rollers. Each time two pinch portions  26   b  and  27   b  enter into contact with the continuous rod  5 , it is pulled sharply away from the cut-off device  19 . The action of the two tension rollers  26  and  27  is also opposed by that of the brake rollers  30  and  31 , so that the portion of the continuous rod  5  extending between the two pairs of rollers will be subjected to a tensile stress causing it ultimately to break (FIG. 3). To advantage, this has the effect of separating a length  21  of forming material in which the tobacco fibers remain substantially whole and can be used again.  
         [0061]    The detached lengths  21  of material emerging from the separation device  1  are then collected by the reclaiming station  22 .  
         [0062]    The problems associated with the prior art are overcome by the present invention, and with notable advantages.  
         [0063]    Firstly, the separation device according to the present invention is able to divide the reclaimable continuous rod  5  into a plurality of lengths  21  containing tobacco fibers that remain intact and are thus reusable. Indeed, because the separation of the continuous rod  5  into discrete lengths  21  is brought about without any cutting action involved, the structural attributes of the tobacco fibers can be preserved.  
         [0064]    It will be appreciated also, that with no need to reject forming material, the costs of manufacturing and/or marketing and selling the tobacco products can be significantly reduced.