Unit for conveying tobacco products

Abstract

Filter plugs or sticks are directed from a filter maker onto a pair of conveyor rollers counter-rotating substantially in contact one with another at a point of tangency and furnished with equispaced peripheral flutes by which the single sticks are taken up and transferred from an infeed position to a release position. The flutes occupying a limited sector of each roller are connected selectively to a source of suction by an internal valve mechanism composed of a slide positionable to set the width of the sector, and a selector sleeve slidable axially between operating positions in which suction is generated across the sector through flutes spaced apart respectively at a longer pitch, and at a shorter pitch equivalent to half of the longer pitch.

1 . A unit for conveying tobacco products, comprising: 
 a pair of rotary conveyors turning in opposite directions substantially in contact one with another at a point of mutual tangency and furnished with angularly equispaced peripheral flutes each serving to accommodate a single product, by which products are transferred from an infeed position to a release position;    conveyor means feeding a succession of products to at least one of the rotary conveyors at the infeed position;    a device by means of which the peripheral flutes occupying at least one sector of predetermined width presented by at least one of the rotary conveyors can be connected selectively to negative pressure means.    
   
   
       2 . A unit as in  claim 1 , wherein the selective connection device is incorporated into each rotary conveyor and comprises valve means serving to regulate the width of the sector, and distribution means serving to vary the number of flutes within the sector that are connected to the negative pressure means.  
   
   
       3 . A unit as in  claim 2 , wherein the valve means comprise a slide with freedom of angular movement, able to assume at least two operating positions each delimiting a respective sector within which negative pressure can be generated through the flutes.  
   
   
       4 . A unit as in  claim 3 , wherein each rotary conveyor comprises a fixed cylindrical element defining a chamber in the form of a sector to a circle, separated by the slide into a portion or sector connected to the negative pressure means and a portion or sector in which pressure is atmospheric.  
   
   
       5 . A unit as in  claim 4 , wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.  
   
   
       6 . A unit as in  claim 5 , wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.  
   
   
       7 . A unit as in  claim 6 , wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.  
   
   
       8 . A unit as in  claim 7 , wherein the measure of the second pitch is equivalent to half the measure of the first pitch.  
   
   
       9 . A unit as in  claim 2 , wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.  
   
   
       10 . A unit as in  claim 9 , wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.  
   
   
       11 . A unit as in  claim 10 , wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.  
   
   
       12 . A unit as in  claim 11 , wherein the measure of the second pitch is equivalent to half the measure of the first pitch.  
   
   
       13 . A unit as in  claim 3 , wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.  
   
   
       14 . A unit as in  claim 13 , wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.  
   
   
       15 . A unit as in  claim 14 , wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.  
   
   
       16 . A unit as in  claim 15 , wherein the measure of the second pitch is equivalent to half the measure of the first pitch.  
   
   
       17 . A unit as in  claim 4 , wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.  
   
   
       18 . A unit as in  claim 17 , wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.  
   
   
       19 . A unit as in  claim 18 , wherein the measure of the second pitch is equivalent to half the measure of the first pitch.  
   
   
       20 . A unit as in  claim 5 , wherein the measure of the second pitch is equivalent to half the measure of the first pitch.