Abstract:
A method of feeding cigarettes, of a length considerably greater than their diameter, to an outlet of a hopper, whereby masses of cigarettes having a number of orientations are fed to an inlet, and the cigarettes are selected according to orientation by means of the orientation and size of the inlet.

Description:
The present invention relates to a method of feeding cigarettes to a hopper outlet. 
     BACKGROUND OF THE INVENTION 
     For manufacturing and conditioning cigarettes in packets, a type of conditioning machine is known which comprises a hopper having an inlet and a number of outlets, each of which outlets comprises closely-spaced partitions defining channels permitting the passage of one cigarette at a time. Each outlet also has a supporting surface located beneath the bottom ends of the channels and for supporting a layer of cigarettes arranged in an orderly succession and containing a given number of cigarettes. 
     The cigarettes are normally fed to the inlet in masses in which the cigarettes are substantially equioriented, i.e. oriented parallel to a given direction, and, in the case of filter-tipped cigarettes, with the filters located on the same side. Not infrequently, however, the masses also contain cigarettes oriented differently from the others, on account of the way in which the masses are transferred: either directly on conveyor belts or in boxes on box conveyors which empty the boxes into the hopper inlet. When conveying the cigarettes or emptying the boxes, in fact, it is virtually impossible to prevent some of the cigarettes from working into a position crosswise to said given direction. Such cigarettes are commonly referred to as “askewed” and create serious difficulties inside the hopper by blocking the outlet channels and forming so-called bridges, i.e. supporting structures defined by cigarettes. “Askewed” cigarettes therefore prevent through-flow of the cigarettes inside the hopper and result in stoppage of the entire conditioning machine. 
     EP-A1-545724 discloses a cigarette hopper having an inlet, a number of outlets, each of which comprises closely-spaced partitions defining channels allowing the passage of one cigarette at a time, and a chamber extending between the inlet and the outlets. The hopper disclosed in EP-A1-545724 also comprises a selecting apparatus, which is arranged inside the chamber and is designed to prevent vane jams of the cigarettes by means of a plurality of curved guides extending from the back to the front of the chamber. 
     The selecting apparatus disclosed in EP-A1-545724 partially eliminates the cigarettes jamming problems originated by the “askewed” cigarettes; however, this selecting apparatus does not work in an optimal manner owing to the difficulty of repositioning or eliminating the “askewed” cigarettes due to the forces, which act on the “askewed” cigarettes in the middle of the chamber and are due to the weight of the mass of cigarettes arranged in the upper portion of the chamber. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a method of the above type, designed to eliminate the aforementioned drawbacks. 
     According to the present invention, there is provided a method of feeding cigarettes to an outlet of a hopper as recited by claim  1 . 
     The present invention also relates to a hopper for supplying cigarettes. 
     According to the present invention, there is provided a hopper for supplying cigarettes as recited by claim  7 . 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
     FIG. 1 shows a schematic, partially sectioned front view, with parts removed for clarity, of a cigarette conditioning machine comprising a preferred embodiment of the hopper according to the present invention; 
     FIG. 2 shows a schematic, partially sectioned, larger-scale front view, with parts removed for clarity, of a detail of the FIG. 1 hopper; 
     FIG. 3 shows a larger-scale plan view, with parts removed for clarity, of the FIG. 2 detail; 
     FIG. 4 shows a section along line IV—IV in FIG. 1; 
     FIG. 5 shows a section along line V—V in FIG. 1; 
     FIG. 6 shows a larger-scale view in perspective of a cigarette. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Number  1  in FIG. 1 indicates as a whole a machine for conditioning cigarettes  2  and which comprises a hopper  3  and is connected to a known device (not shown) for supplying masses  4  of cigarettes. 
     With reference to FIG. 6, each cigarette  2  comprises a cigarette portion  5  and a filter  6  attached to portion  5 ; is substantially cylindrical with an axis  7 ; and has a given diameter D and a given length L equal to roughly thirteen times diameter D. 
     Hopper  3  houses cigarettes  2  with respective axes  7  parallel to a direction D 1  perpendicular to the FIG. 1 plane, and comprises a front wall  8 , a rear wall  9  parallel to and separated from wall  8  by a distance approximately equal to but no less than length L of cigarettes  2 , and two lateral walls  10  and  11  laterally defining a loading chamber  12  of hopper  3 . Hopper  3  also comprises nine outlets  13  defining loading chamber  12  at the bottom of hopper  3 ; and each outlet  13  comprises a number of partitions  14  perpendicular to the FIG. 1 plane and a given distance apart to define channels  15 , each for housing a respective column  16  of cigarettes  2 . Each outlet  13  is located over a plate  17  for supporting a layer  18  containing a given number of cigarettes  2  arranged in an orderly succession. Hopper  3  also comprises a conveyor  19  for conveying masses  4  of cigarettes  2  in a horizontal direction D 2  parallel to the FIG. 1 plane, and along a given path P. Conveyor  19  defines the top of hopper  3 , and comprises two guide walls  20  (only one shown in FIG. 1) and six belt conveyors  21  arranged successively between walls  20 . 
     As shown more clearly in FIG. 4, walls  20  are substantially coplanar with front wall  8  and rear wall  9  respectively, and extend in direction D 2 . 
     With reference to FIGS. 2 and 4, each conveyor  21  comprises two pulleys  22  rotating about respective axes  23  parallel to direction D 1 ; and a number of trapezoidal belts  24 , which have an outer major face  25  and an inner minor face  26 , are looped about pulleys  22 , and have a top work branch  27  and a bottom return branch  28 . 
     Each pulley  22  comprises a cylindrical outer wall  29  in which are formed a number of trapezoidal-section grooves  30 , which extend about axis  23 , are equally spaced along axis  23 , and house respective belts  24  so that faces  25  of belts  24  are coplanar with wall  29 . 
     The distance, measured in direction D 2 , between walls  29  of two adjacent pulleys  22  of two successive, adjacent conveyors  21  is equal to roughly three times diameter D of cigarettes  2 , so that walls  20  and the adjacent pulleys  22  of two successive, adjacent conveyors  21  define an inlet  31  of hopper  3 . Each inlet  31  has a minimum section S 1  of length L 1  equal to the minimum distance between walls  20 , i.e. approximately equal to but no less than length L of cigarettes  2 ; a width W 1  equal to roughly three times diameter D of cigarettes  2 , i.e. considerably smaller than length L of cigarettes  2 ; and a maximum section S 2  equal to the maximum distance between walls  29 , in turn equal to the distance between axes  23  of the two pulleys  22 , i.e. equal to roughly six times diameter D of cigarettes  2 . 
     With reference to FIG. 5, each conveyor  21  also comprises, for each belt  24 , a protective casing  32 , which extends between the two pulleys  22  and branches  27  and  28 , and in turn comprises two lateral wings  33  for guiding belt  24  along bottom branch  28 , and a wall  34  for guiding top branch  27  and which is substantially parallel to and facing inner face  26  of belt  24  along top branch  27 . Each casing  32  is supported by sleeves C extending between walls  20 . 
     The distance between adjacent belts  24  of the same conveyor  21 , and the distance between the end belts  24  and adjacent walls  20  are such that the minimum gap, measured in direction D 1 , between adjacent belts  24  and between each end belt  24  and the adjacent wall  20  is greater than and substantially equal to twice diameter D of cigarettes  2 . 
     The distance between the axes of the two pulleys  22  of each conveyor  21  is such that the minimum distance, measured in direction D 2 , between outer walls  29  of said pulleys  22  is greater than length L of cigarettes  2 . In other words, walls  20  and belts  24  and pulleys  22  of each conveyor  21  define a number of expulsion inlets  35  for expelling cigarettes  2 , and each of which has a minimum section S 3  of a length L 2  greater than length L of cigarettes  2 , and a width W 2  equal to roughly twice diameter D of cigarettes  2 . 
     In other words, conveyor  19  defines a horizontal surface A along which inlets  31  to chamber  12  of hopper  12  alternate with expulsion inlets  35 . 
     Hopper  3  also comprises a number of separators  36 , each of which is located inside chamber  12 , directly beneath a respective conveyor  21 , and in turn comprises two substantially vertical walls  37  extending between walls  8  and  9  and aligned with axes  23  of pulleys  22 , and two walls  38  sloping with respect to walls  37 , extending between walls  8  and  9 , and connected to walls  37  and to each other to form a downward-facing cusp  39 . 
     Separators  36  divide chamber  12  of hopper  3  into a chamber  40  extending substantially in direction D 2  and located directly over outlets  13 ; and into a number of channels  41  extending in a vertical direction D 3  perpendicular to directions D 1  and D 2 , and which connect respective inlets  31  to chamber  40 , and are connected to chamber  40  by walls  38 . 
     Each channel  41  is defined by the adjacent walls  37  of two adjacent separators  36 , which walls  37  are separated by a distance smaller than the length L of cigarettes  2 . In FIG. 2, the distance between said walls  37  is substantially equal to six times the diameter of cigarettes  2 . 
     With reference to FIG. 4, each separator  36  houses a channel  42  for expelling cigarettes  2  from hopper  3 . Each channel  42  is defined by walls  8  and  9  of hopper  3 , by walls  37  of separator  36 , and by a bottom wall  43 , which slopes with respect to the FIG. 2 plane, and has a top end  44  located close to wall  8 , and a bottom end  45  extending through an opening  46  formed in wall  9 . Channel  42  is located directly beneath a respective conveyor  21 , and therefore communicates with inlets  35  of conveyor  21 . 
     The height of chamber  40  is limited by the distance between cusps  39  and the top ends of channels  15  of outlets  13  being equal to roughly ten times diameter D. 
     In actual use, masses  4  of cigarettes are transferred to hopper  3  and deposited on to conveyor  19  by a known transfer device (not shown). The masses  4  on conveyor  19  comprise cigarettes  2  oriented within a range I 1  about direction D 1 , i.e. either oriented in, or inclined relatively slightly with respect to, direction D 1 ; and cigarettes  2   a  oriented within a range I 2  about direction D 2 . Cigarettes  2   a  are exactly the same size as, and only differ from cigarettes  2  by being oriented differently. 
     Mass  4  is fed by conveyor  19  along path P in direction D 2 , so that cigarettes  2  and  2   a  are fed successively over inlets  31  and expulsion inlets  35 . The cigarettes  2  located directly over an inlet  31  drop through inlet  31  into respective channel  41  underneath, whereas the cigarettes  2  over inlet  31  but separated from inlet  31  by other cigarettes  2  and/or  2   a  are fed by conveyor  19  to the next inlet  31  and  35 . The cigarettes  2   a  located directly over an inlet  35  along path P drop through inlet  35  and are fed by wall  43  through opening  46  into known collecting bins (not shown), whereas the cigarettes  2   a  not directly over inlet  35  are fed to the next inlet  35 . 
     The cigarettes  2  dropping through inlets  31  are guided by respective channels  41 , which are so sized as to prevent cigarettes  2  from working into a position parallel to direction D 2 , and guide cigarettes  2  into chamber  40  where cigarettes  2  form a relatively thin layer  47  of a thickness less than ten times diameter D of cigarettes  2 . The cigarettes  2  in layer  47  then drop one at a time into respective channels  15  of outlets  13 . 
     In other words, cigarettes  2  and  2   a  are selected according to orientation, for which purpose, inlets  31  and  35  have respective elongated minimum sections S 1  and S 3  oriented in directions D 1  and D 2  respectively. That is, as a function of the orientation of cigarettes  2  and  2   a , inlets  31  allow cigarettes  2  and deny cigarettes  2   a  access to chamber  12 , while inlets  35  allow cigarettes  2   a  and deny cigarettes  2  access to expulsion channel  42 . 
     The method and hopper  3  described afford various advantages, foremost of which is that of preventing cigarettes  2   a  from entering chamber  12  of hopper  3 . In which connection, it should be pointed out that it would be far more complicated to eliminate cigarettes  2   a  once inside chamber  12  of hopper  3 . 
     A further advantage lies in channels  41  preventing any variation in the orientation of cigarettes  2  as they are fed down channels  41 . 
     Moreover, the relatively thin layer  47  formed over outlets  13  of hopper  3  prevents the formation of bridges preventing downflow of cigarettes  2 . 
     Clearly, the dimensions of inlets  31  and  35  referred to herein are purely indicative and based on threshold orientation values of cigarettes  2  and  2   a . That is, a reduction in width W 1  of the minimum section of inlet  31  allows the entry of cigarettes  2  oriented practically parallel to direction D 1 ; whereas increasing width W 1  also permits the entry of cigarettes  2  which are far from parallel to direction D 1  or even oriented at an angle of roughly 45° with respect to D 1 . The same obviously also applies to the sizing of expulsion inlets  35 . 
     Finally, by appropriately selecting the diameter of pulleys  22 , it is possible to achieve a given ratio between the maximum section S 2  and the minimum section S 1  of inlets  31 , and select the cigarettes  2  which can be rearranged without being subjected to excessively severe stress. As such, cigarettes  2  oriented crosswise to direction D 1 , and which would not drop through minimum section S 1 , engage the gap between the two pulleys  22 , drop through maximum section S 2 , and are substantially oriented in direction D 1  as they drop between the two pulleys  22 , the walls  29  of which form curved connections between maximum section S 2  and minimum section S 1 .