Abstract:
A supply unit and a user unit employed in the manufacture of tobacco products, typically cigarettes and the like, are linked by a duct along which a mass of the cigarettes is advanced from the outfeed of the supply unit toward the infeed of the user unit. The advancing mass of cigarettes is parted at an intermediate zone of the duct either by rods or by a pair of frames, in such a way as to create a void that will accommodate a trolley directed into the duct from a housing by an elevator; once inside the duct, the trolley proceeds to push the mass of cigarettes from the intermediate zone toward the inlet of a hopper in such a way as to empty the duct completely, for example when changing over from one brand of cigarette to another. To advantage, the trolley is composed of two articulated structures so that its geometry and dimensions can be varied to match the variations in geometry and depth of the duct.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a device linking a supply unit and a user unit for the manufacture of tobacco products. 
   It is the practice among manufacturers of tobacco products to connect a supply unit, consisting by way of example in a cigarette maker or filter tip attachment, to a user unit such as a packer. The connection is provided normally by means of a duct extending along a path that presents straight horizontal and vertical portions joined together by curved portions, along which a flow of cigarettes is caused to advance continuously as a compact mass with the single cigarettes disposed transversely to the conveying direction. It is a necessary condition for the smooth operation of such a link that the mass of cigarettes be maintained as compact as possible, in order to prevent the single cigarettes from becoming positioned incorrectly as they advance. 
   Conversely, it will often happen during operation of the machine units in question that the flow is interrupted for various reasons, such as a break in the flow from the supply unit caused by a failure or by a pause to enable changeover from one brand of cigarette to another. 
   In these situations, the interrupted flow causes a loss of compactness in the mass of cigarettes, with the result that the distribution of the cigarettes is rendered disorderly and requires the attention of an operator. Besides seeking to restore the compactness of the mass, the operator will also have to remove all of the cigarettes from the duct. 
   The object of the present invention is to provide a device for linking a supply unit and a user unit handling tobacco products, such as will be unaffected by the above noted drawback. 
   SUMMARY OF THE INVENTION 
   The stated object is realized according to the present invention in a device linking a supply unit and a user unit for the manufacture of tobacco products, comprising at least one feed duct along which to direct a mass of products from the outfeed of a supply unit to the infeed of a user unit, wherein the duct presents two guide walls determining the depth of the mass of products. 
   To advantage, the device comprises means by which to separate the mass of products at a predetermined zone of the duct, and mobile means capable of traveling along the duct from the predetermined zone through a predetermined distance. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: 
       FIG. 1  illustrates a device linking a supply unit and a user unit for the manufacture of tobacco products according to the present invention, viewed schematically in a side elevation with certain parts omitted; 
       FIG. 2  shows an enlarged detail of the device in  FIG. 1 , viewed schematically in a side elevation with certain parts omitted for clarity, and in different operating configurations; 
       FIG. 3  shows the detail of  FIG. 2  schematically and in perspective with certain parts omitted for clarity; 
       FIGS. 4 ,  5  and  6  are schematic side elevations illustrating the device of  FIG. 1  in three successive operating steps; 
       FIG. 7  is an enlargement of  FIG. 4 ; 
       FIG. 8  shows the detail of  FIG. 7  in a plan view; 
       FIG. 9  is an enlarged side elevation showing the detail of  FIG. 7  located in a curved portion of the link and in a different operating configuration; 
       FIGS. 10 and 11  are perspective views showing an enlarged detail of the device in  FIG. 1 , illustrated in a second embodiment and seen in two successive operating steps; 
       FIG. 12  shows the device of  FIG. 6  in an alternative embodiment; 
       FIG. 13  is a schematic showing the device of  FIG. 1  in an alternative embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1  of the drawings,  1  denotes a device, in its entirety, serving to link a supply unit  2  consisting by way of example in a machine turning out cigarettes  3 , and a user unit  4  consisting likewise by way of example in a packaging machine. 
   The device  1  comprises a feed duct  5  inside which a mass  6  of cigarettes  3  is made to advance along a predetermined path  7  in a predetermined direction  8  normal to the longitudinal axes of the cigarettes  3 . In the example illustrated, the duct  5  comprises a substantially horizontal first straight leg  9  departing from the supply unit  2  and connected by way of a curved leg  10  to a substantially vertical second straight leg  11  terminating at the inlet  12  of an infeed hopper  13  serving the user unit  4 . 
   The feed duct  5  is supported by a frame (not illustrated) comprising an upright member  14 , delimited horizontally by a bottom wall  15  and a top wall  16  establishing the depth of the enclosure, and compassed laterally by two vertical walls  17 . The bottom wall  15  coincides with the horizontal top branch  15   a  of a belt conveyor  15   b , of which  FIG. 1  illustrates only a part, occupying a section of the duct  5  that extends from an intermediate zone  18  to the curved leg  10 . 
   As illustrated in  FIGS. 1 ,  4 ,  5 ,  6 ,  7  and  8 , the straight horizontal leg  9  of the feed duct  5  presents an opening  19  in the bottom wall  15 , coinciding with the intermediate zone  18  mentioned above. 
   The opening  19  is occupied by a pair of belt conveyors  20  spaced apart transversely to the feed direction  8  and aligned substantially with the conveyor  15   b  first mentioned. 
   As illustrated to advantage in  FIGS. 4 ,  5 ,  6  and  7 , each of the two conveyors  20  is looped around two end pulleys  21  and  22  to create a top branch  23  occupying the same plane as the bottom wall  15  and/or the top branch  15   a  of the first conveyor  15   b , and around a bottom pulley  24  interposed between two diverting rollers  25 . 
   One end pulley  22  of each belt is associated with respective drive means not illustrated in the drawings, whilst the other end pulley  21 , located downstream relative to the feed direction  8  followed by the mass  6  of cigarettes  3 , is capable of movement back and forth parallel to the feed direction  8 , guided by a respective slide  21   a  (see  FIG. 8 ) coupled with a relative lateral track  21   b . The two tracks  21   b  are positioned on opposite sides of the duct  5 , as indicated in  FIG. 8 . 
   The movement of each end pulley  21  is brought about as a result of the relative bottom pulley  24  of the conveyor  20  being traversed in the corresponding vertical direction through the agency of conventional actuator means not illustrated in the drawings. Accordingly, each belt conveyor  20  presents one retractable end coinciding with the movable end pulley  21 . 
   The belt conveyors  20  combine to create a passage at the intermediate zone  18 , afforded to mobile means denoted  26  in their entirety, which, from an at-rest position internally of a relative housing  27 , outside the dimensional compass of the duct  5 , are able to enter the duct  5  and thereupon to travel along the feed path  7  from the intermediate zone  18  through a given distance. In the event that the transverse dimension of the mobile means  26  is greater than the distance separating the two conveyors  20 , a passage of width sufficient to admit the selfsame means  26  can be created by retracting the movable pulleys  21  parallel with the feed direction  8 , as indicated in  FIGS. 5 and 6 . 
   Referring in particular to  FIGS. 7 ,  8  and  9 , the mobile means  26  comprise a trolley  28  incorporating first and second articulated structures  29  positioned side by side and connected together by first and second shafts  30  and  31  extending transversely to the feed path  7  and parallel to the axes of the cigarettes  3 . 
   The first shafts  30  are four in number and placed at the four corners of the articulated structures  29 , whilst the second shafts  31  are two in number and occupy intermediate positions between each pair of first shafts  30 . The trolley also comprises a set of wheels  32  mounted rotatably to the opposite ends of each of the two top first shafts  30  and the two bottom first shafts  30 , and a set of wheels  33  mounted to the opposite ends of each second shaft  31 . 
   Also associated pivotably with the ends of each top first shaft  30  are first ends of two first rods  34 , of which the remaining ends are associated pivotably with the ends of the top second shaft  31 . 
   Similarly, the opposite ends of two first rods  34  are associated pivotably with the ends of each bottom first shaft  30  and with the ends of the bottom second shaft  31 , respectively. 
   In particular, the two top first rods  34  are disposed in mutual alignment along the direction  8  of the feed path  7  and substantially parallel to the two bottom first rods  34 , likewise aligned mutually along the direction  8  of the feed path  7 . Each of the wheels denoted  33  occupies an intermediate position between the two respective top and the two respective bottom corner wheels  32 . 
   The opposite ends of each first shaft  30  also provide pivots for respective first ends of second rods  35 , of which the second ends are united by way of respective common hinges  36 . More exactly, each of the first and second articulated structures  29  is identifiable as having first hinges  37  coaxial with the first shafts  30 , second hinges  38  coaxial with the second shafts  31  and third hinges coinciding with the aforementioned common hinges  36 . 
   Observing  FIG. 7 , it will be seen that the second rods  35  of each articulated structure  29  are arranged in pairs and disposed in a Vee formation of which the vertex coincides with the third hinge  36 . The two top and the two bottom corner wheels  32  of each articulated structure  29  function as end pulleys for respective conveyor means  39  consisting in relative belt loops  40  each wrapped around two end wheels  32  and located in contact with the relative intermediate wheel  33 . The conveyor means  39  provide transport means  41  by which the trolley  28  is rendered capable of movement along the feed duct  5 . In the event that the trolley  28  is equipped with its own drive means, as will be explained in due course, the transport means  41  will consist in traction means  42  providing each articulated structure  29  with top and bottom live surfaces denoted  43  and  44  respectively. 
   The live surfaces  43  and  44  of each articulated structure  29  are afforded respectively by the top branch of the top belt loop  40  and the bottom branch of the bottom belt loop  40 . Viewing the trolley  28  in its entirety ( FIGS. 7 and 8 ), the two top branches of the top belt loops  40  thus combine to establish a top face  47  of the trolley  28 ; similarly, the two bottom branches of the bottom belt loops  40  combine to establish a bottom face  48  of the trolley  28 . 
   The articulated structure  29  further comprises angle brackets  45  attached by first ends to the first hinges  37  at opposite ends of each of the four first shafts  30 . Each bracket  45  presents a pin  46  located at an intermediate point on its length and disposed parallel to the axes of the shafts  30 . Thus, the front aspect of the trolley  28 , considered in its entirety, presents two pairs of brackets  45  arranged with the relative pins  46  coaxially disposed, and with one end of an elastic band  49  looped around each pair of pins  46 . Similarly, the rear aspect of the trolley  28  presents two further pairs of brackets  45  arranged with the relative pins  46  coaxially disposed and with one end of an elastic band  50  looped around each pair of pins  46 . 
   The free ends of the brackets  45  combine with the external branches of the bands  49  and  50  to establish a front face  51  and a rear face  52  of the trolley  28 . 
   It will be seen from the foregoing that the nature of the two articulated structures  29  making up the trolley  28  is such as to allow variations in width and geometry of the selfsame trolley by rotating the first and second rods  34  and  35  about the hinges  36 ,  37  and  38 , in such a manner as to maintain the transport means  41  firmly in contact with the guide walls  15  and  16  as the trolley  28  advances along the feed duct  5 . 
   To this end, the trolley  28  is equipped with active components denoted  53 , indicated schematically in the drawings, such as will allow of varying the distance between the transport means  41 , or between the live surfaces  43  and  44  if the trolley has its own drive means. The active components in question might take the form of coil springs  54  coupled to the third hinges  36  in such a way that the variation of the angle compassed by the second rods  35  is controlled elastically. Alternatively, such components could be magnets  55  placed along each of the first rods  34  and designed to interact with the guide walls  15  and  16  of the feed duct  5 . In this instance the walls  15  and  16  might be embodied in ferromagnetic or magnetic material, or incorporate cores of such material, so as to interact with the magnets  55  of the trolley  28 . 
   The trolley  28  also carries drive means  56 , indicated schematically in  FIG. 8 , capable of actuating at least one of the aforementioned live surfaces  43  or  44  by way of the respective shafts  30  or  31 . The drive means  56  can be coupled to the shafts in such a way that rotation is transmitted to at least one of the respective wheels  32  or  33 . 
   The drive means  56  in question are powered by a rechargeable battery indicated schematically as a block  57 , which is interlocked to a control unit  58 . The unit  58  will be equipped with receiving means  77  able to pick up electromagnetic waves used to control the movements of the trolley  28 . 
   The sizing of the drive means  56 , the battery  57  and the control unit  58  may be such as to occasion appreciable changes in the proportions of the central part of the trolley  28 , though without modifying the transverse distance between the belt loops  40 . 
   As illustrated particularly in  FIGS. 4 ,  5 ,  6  and  7 , the device comprises lifting means  59  aligned with the predetermined intermediate zone  18  of the duct  5 , comprising, for example, a table  60  on which the trolley  28  is supported when occupying the housing  27  and lying outside the duct  5 . The table  60  is capable of movement, induced by the lifting means  59 , between a lowered at-rest position inside the housing  27  as illustrated in  FIGS. 4 and 7 , and a raised position of nominal alignment with the bottom guide wall  15  and/or the top branch  15   a  of the belt conveyor  15   b  first mentioned, allowing the trolley  28  to assume an operating position internally of the feed duct  5  as illustrated in  FIG. 6 . 
   In order to create a space within the mass  6  of cigarettes  3  at the intermediate zone  18  and thus allow the trolley  28  to be introduced into the feed duct  5 , the device comprises means denoted  61  in their entirety, by which to separate the mass  6  of cigarettes. Such means  61  comprise a pair of vertical rods  62  extending substantially perpendicular to the feed path  7  and capable of movement along respective trajectories inside the duct  5 , near to the vertical walls  17 . The vertical rods  62  are movable between a position outside the compass of the duct  5 , indicated in  FIGS. 4 and 7 , and an operating position internally of the duct  5  and immediately upstream of the trolley  28  in the feed direction  8  followed by the mass  6 . 
   The movement of the rods  62  is timed to coincide with that of the table  60  between the at-rest and operating positions. In this instance, as discernible from  FIG. 5 , the top branches of the belt loops  40  that provide the transport means  41  form part of the separating means  61  and operate in conjunction with the rods  62 , functioning as means by which to remove the cigarettes  3  from the part of the duct  5  about to be occupied gradually by the trolley  28 , whereas once inside the duct  5 , the rods  62  function as retaining elements serving to block the mass  6  of cigarettes  3  upstream of the intermediate zone  18 . 
   In operation, supposing that the duct  5  is to be emptied completely, for example following a lengthy pause due to inactivity of the supplier unit and/or to a change of brand, the movement of the mass  6  of cigarettes  3  is brought to a halt in the part of the duct  5  upstream of the trolley  28 , the top branch  15   a  of the downstream belt conveyor  15   b  is set in motion, and the separating means  61  are activated. More exactly, the trolley  28  is elevated by the lifting means  59  from the housing  27  up into the duct  5 , causing the two belt loops  40  of the top live surfaces  43  to pass between the two conveyors  20  and into contact with the mass  6  of cigarettes  2 . At this juncture, in the event that the dimensions of the trolley  28  beneath the respective live surfaces  43  are greater than the distance between the two conveyors  20 , as mentioned previously, the end pulleys  21  will retract to enable the passage of the trolley  28  through the opening  19 . 
   During the elevation of the trolley  28 , the two live surfaces  43  afforded by the top branches of the belt loops  40  will translate in the feed direction  8  and thus favor the displacement of the cigarettes  3  in the part of the mass  6  occupying the intermediate zone  18 ; the moving elements in question thus provide means  40  and  43  by which to remove the mass  6  of cigarettes  3  from the intermediate zone  18  and are one and the same as the conveyor means  39 , which thus perform the function of outfeed conveyors in respect of the mass  6  of cigarettes occupying the zone  18 . 
   The paired rods  62  of the separating means  61  operate in conjunction with the trolley  28 , moving perpendicularly into the duct  5  so as to establish a retaining wall by which the mass  6  of cigarettes  3  located upstream of the intermediate zone  18  is held back as indicated in  FIG. 6 . 
   Once the trolley  28  reaches its upper travel limit, the movement of the top live surfaces  43  is reversed and the bottom live surfaces  44  are activated, with the result that these same surfaces will engage the top wall  16  of the duct  5  and the surface of the table  60 , respectively, and cause the trolley  28  to advance along the duct  5  in the feed direction  8 . The trolley  28  is now carried toward the inlet  12  of the infeed hopper  13  on the top branch  15   a  of the downstream conveyor  15   b , its front face  51  pushing the mass  6  of cigarettes forward so that the stretch of the duct  5  between the intermediate zone  18  and the inlet  12  of the infeed hopper  13  is emptied completely. During this step, the front face  51  provides means by which to push the mass  6  of cigarettes. More exactly, such pushing means  51  consist in the elastic band  49  and the free ends of the corresponding pairs of angle brackets  45 , which also provide contact means of variable length offered directly to the mass  6  of cigarettes. 
   As illustrated in  FIGS. 2 and 3 , the trolley  28  arrives at the inlet  12  of the hopper  13  disposed with the four live surfaces  43  and  44  in contact with the side walls  15  and  16  of the vertical leg  11  of the duct  5 , and the front face  51  lying horizontally near the mouth of the hopper  13 . 
   At this point, as illustrated schematically in  FIG. 3 , the trolley  28  is transferred from its position occupying the mouth of the hopper  13 , through the agency of conventional translation means (not indicated), to the inlet  63  of a return duct  64  extending beneath and parallel with the feed duct  5  back to the housing  27 . Once inside the inlet  63 , the trolley  28  is turned through 90° by the action of flipper means, likewise conventional and not illustrated, and directed into the return duct  64 . The trolley  28  thereupon returns to the housing  27  under the power of its own drive means  56  and repositions in readiness for a further cycle. The housing  27  is equipped with means  65  for recharging or replacing the battery  57 . 
   Importantly, as indicated in  FIG. 9 , when the trolley  28  passes along the curved leg  10  of the feed duct  5 , the articulated structures  29  and the active components  53  combine to maintain the belt loops  40  of the live surfaces  43  and  44  in contact with the walls  15  and  16  of the duct  5 . Accordingly, the front and rear elastic bands  49  and  50  will vary in length as the cross section of the duct  5  becomes wider. Like the front band  49 , the rear band  50  and the corresponding pairs of angle brackets  45  function as contact means of variable length offered directly to the mass  6  of cigarettes. 
   Likewise of importance is the fact that, instead of regaining the housing  27  by way of the return duct  64  described above, the trolley  28  can also reverse back along the duct  5  under the power of its own drive means  56  and the live surfaces  43  and  44  and/or carried by the top branch  15   a  of the conveyor  15   b , running in the opposite direction, ultimately assuming a position of proximity to the supply unit  2  and engaging in contact with the remaining mass  6  of cigarettes  3  retained upstream of the two vertical rods  62  so that these same cigarettes can be diverted into a recipient, for example, a storage bin  66 . As the trolley  28  reaches the position occupied by the vertical rods  62 , the rods will retract. In practice, the bin  66  will be connected to the duct  5  by way of a vertical leg  11 ′ of which the inlet end is connected to the duct  5  by way of an opening  19 ′ occupied by a pair of retractable conveyors  20 ′ identical to the conveyors  20  already described. 
   Another function is performed by the trolley  28  on assuming the aforementioned position of proximity to the supply unit  2 . With the trolley  28  in this same position, or at least in a position substantially coinciding with the intermediate zone  18 , the mass  6  of new cigarettes can be engaged by the rear face  52  and their passage toward the inlet  12  of the infeed hopper  13  thus accompanied and controlled by the trolley  28 , which thereafter will be shifted sideways and flipped through 90° as already described. Accordingly, the rear face  52  provides means by which to cushion the mass  6  of cigarettes  3  and accompany it along the duct  5 . 
   In the case described previously, the rear elastic band  50  and the free ends of the two pairs of angle brackets  45  provide means by which to cushion and accompany the mass  6  of cigarettes  3  to the end of restoring normal operating conditions. 
   In the example of  FIG. 10 , the step of directing the trolley  28  into the duct  5  at the intermediate zone  18  is preceded by a step of creating a void in the mass  6  of cigarettes through the agency of separating means  61  which in this instance appear as spreader means, denoted  67  in their entirety. More particularly, such means  67  comprise two frames  68 , each mounted to a relative shaft  69  positioned transversely to the feed direction  8  and rotatable about a corresponding axis  69   a  through the agency of actuator means  70 . The shafts  69  in their turn are mounted to a rigid structure rising from the table  60  and consisting in two pairs of vertical rods  71 . The rigid structure is set in motion vertically by two respective actuators  72  and comprises guides  73 , coupled with the rods  71 , on which the table  60  is slidable during the vertical movement produced by the aforementioned lifting means  59 . 
   In operation, during the elevating movement brought about by the actuator means  72 , the frames  68  can be positioned at first substantially parallel to the duct  5 , then, on reaching a position substantially in the same plane as the bottom wall  15  of the duct  5 , spread to assume the separating position. 
   When fully spread, the two frames  68  will be positioned mutually parallel and set transversely to the channel  5 , compassing a void of length sufficient to accommodate the trolley  28 . 
   In a further arrangement, the two frames  68  might be angled relative to the feed direction followed by the mass  6  of cigarettes  3 , with the free ends in mutual contact and creating a wedge element  74 . 
   The wedge element  74  is capable of movement between a position outside the dimensional compass of the feed duct  5 , and a position of penetration within the mass  6  of cigarettes. On reaching the latter position, the two frames  68  will be rotated away from one another by the respective actuators  70  and positioned mutually parallel, transversely to the channel  5 , separating the mass  6  of cigarettes and creating a space able to accommodate the trolley  28  when raised into the duct  5  by the lifting means  59 . 
   In both of the cases described, as illustrated in  FIG. 11 , the inserted trolley  28  is able to travel along the duct  5  either under the power of its own drive means  56  or through the agency of a pusher  75  insertable, needless to say, between the two uprights of the frame  68  on the downstream side. 
   The trolley  28  proves especially advantageous in a situation where the duct  5  covers a particularly long path and incorporates a first-in-first-out (FIFO) type of temporary storage facility  76  through which the mass  6  of cigarettes  3  is directed. 
   Whilst the examples described and illustrated all relate to a single trolley  28  able to perform the steps of pushing or accompanying the mass  6  of cigarettes  3  along the duct between the intermediate zone  18  and the inlet  12  of the infeed hopper  13 , or between the intermediate zone  18  and the outfeed of the supply unit  2 , in this instance directing the mass  6  into the storage bin  66 , it is possible nonetheless to employ two or more such trolleys  28  able to perform a plurality of operations at once. For example, the device might utilize two trolleys  28  of which one can operate while the other is parked in the housing  27  to allow recharging or replacement of the battery  57 .