Apparatus for building a tobacco stream

Abstract

A distributor for comminuted tobacco wherein a first conveyor, such as a carded drum, an endless apron or a pneumatic conveyor, supplies tobacco at a variable rate into the path of orbital movement of bristles on a rapidly rotating accelerating device. The bristles propel the particles of tobacco onto a narrow foraminous transporting belt which travels in a horizontal channel and accumulates a dense tobacco stream which is transported past a trimming device and into the wrapping mechanism of a cigarette rod making machine. The accelerating device is driven by a separate motor so that the peripheral speed of its bristles exceeds the speed of tobacco travel on the first conveyor. The stream is attracted to the transporting conveyor by suction, and the accelerating device is placed sufficiently close to the channel to insure that, during impact against the transporting conveyor or against the layer of tobacco thereon, the kinetic energy of all or nearly all tobacco particles is substantially identical. The accelerating device can be placed below, between or above the first conveyor and transporting conveyor and may form part of a winnowing assembly.

What is claimed as new and desired to be protected by Letters Patent is: .[.set forth in the appended claims.]. 
     
       1. In a machine for the making of tobacco filler rods, apparatus for building a tobacco stream comprising a source of comminuted tobacco; a tobacco feeding unit arranged to draw tobacco from said source and including a first conveyor operable at a plurality of speeds to transport the withdrawn tobacco along a first portion of a predetermined path; a tobacco stream transporting second conveyor adjacent to means defining a relatively narrow second portion of said path; an accelerating device comprising a rotary conveyor and wall means defining with said rotary conveyor a funnel which receives tobacco supplied by said first conveyor, said accelerating device being disposed between said .Iadd.first and second .Iaddend.conveyors and operative to mechanically accelerate comminuted tobacco for transfer into and densification in said narrow second portion of said path wherein the accelerated tobacco forms a narrow growing stream which is transported by said second conveyor; and means for operating said accelerating device independently of at least one of said .Iadd.first and second .Iaddend.conveyors. 
     
     
       2. Apparatus as defined in claim 1, wherein said first conveyor is located at a level above said accelerating device and the tobacco descends by gravity into the range of said accelerating device. 
     
     
       3. Apparatus as defined in claim 1, wherein said first conveyor is located at a level below said second conveyor. 
     
     
       4. Apparatus as defined in claim 1, wherein said second conveyor is located at a level above said accelerating device. 
     
     
       5. Apparatus as defined in claim 1, wherein said accelerating device is located at a level above said second conveyor. 
     
     
       6. Apparatus as defined in claim 1, further comprising means for classifying the particles of comminuted tobacco in advance of said accelerating device. 
     
     
       7. Apparatus as defined in claim 6, wherein said classifying means is located at a level above said accelerating device. 
     
     
       8. Apparatus as defined in claim 1, wherein said first conveyor is arranged to draw tobacco from said source and said feeding unit further comprises means for removing tobacco from said first conveyor, said accelerating device being disposed at a level above said second conveyor and below said removing means and said removing means being arranged to supply tobacco to said accelerating device by gravity flow. 
     
     
       9. Apparatus as defined in claim 8, wherein said first conveyor is a carded conveyor and said removing means comprises a picker roller. 
     
     
       10. Apparatus as defined in claim 9, wherein said feeding unit further comprises refuser means for equalizing the comminuted tobacco which is being drawn from said source by said carded conveyor. 
     
     
       11. Apparatus as defined in claim 1, further comprising an elongated tobacco channel provided with an elongated suction chamber, said second conveyor consisting of foraminous material and having an elongated stretch one side of which is adjacent to said chamber and the other side of which receives tobacco from said accelerating device. 
     
     
       12. Apparatus as defined in claim 1, wherein said second portion of said path is substantially normal to said first portion of said path, said first conveyor being arranged to supply a sliver of comminuted tobacco and said accelerating device comprising a rotary conveyor having an axial length at least approximating the width of the sliver on said first conveyor. 
     
     
       13. Apparatus as defined in claim 1, further comprising prime mover means for driving said first conveyor in synchronism with said second conveyor, said means for operating said accelerating device comprising a discrete motor. 
     
     
       14. Apparatus as defined in claim 13, wherein said first and second conveyors are endless belts. 
     
     
       15. Apparatus as defined in claim 1, wherein the filler rod produced by said machine has a predetermined density and said means for operating said accelerating device comprises means for driving said rotary conveyor at a peripheral speed which is high enough to impart to comminuted tobacco a kinetic energy sufficient to build on said second conveyor a tobacco stream whose density exceeds one-half of said predetermined density. .Iadd. 16. In a machine for the making of tobacco filler rods, apparatus for building a tobacco stream comprising a source of intermixed lighter and heavier tobacco particles, particularly intermixed tobacco shreds and ribs; a tobacco feeding unit arranged to draw tobacco particles from said source and including a first conveyor operable at a plurality of speeds to transport the withdrawn tobacco particles along a first portion of a predetermined path; channel means defining a relatively narrow second portion of said path; a second conveyor adjacent to said channel means and arranged to transport tobacco particles along said second portion of said path; means for transferring tobacco particles from said first conveyor and for transferring lighter particles onto said second conveyor, including an accelerating device comprising a rotary third conveyor and wall means defining with said third conveyor a funnel which receives tobacco particles supplied by said first conveyor, said accelerating device being disposed intermediate said first and second conveyors and being operative to mechanically accelerate said lighter and heavier particles whereby the flight spans of said heavier particles are different from the flight spans of said lighter particles with attendant segregation of said lighter particles from said heavier particles, said lighter particles being transferred into and densified in said channel means wherein said lighter particles form a narrow growing stream which is transported by said second conveyor; means for operating said third conveyor independently of at least one of said first and second conveyors; and means for intercepting said segregated heavier particles. .Iaddend..Iadd. 17. Apparatus defined in claim 16, wherein said transferring means further comprises means for removing lighter and heavier tobacco particles from said first conveyor. .Iaddend..Iadd. 18. Apparatus as defined in claim 17, wherein said lighter and heavier tobacco particles form on said first conveyor a relatively wide sliver and said first conveyor is a carded conveyor. .Iaddend..Iadd. 19. Apparatus as defined in claim 18, wherein said removing means comprises a picker roller. .Iaddend..Iadd. 20. Apparatus as defined in claim 16, wherein said third conveyor comprises a substantially cylindrical brush having an annulus of bristles. .Iaddend..Iadd. 21. Apparatus as defined in claim 16, wherein said operating means includes means for rotating said third conveyor at a peripheral speed exceeding each of said plurality of speeds. .Iaddend..Iadd. 22. Apparatus as defined in claim 16, further comprising a separator chamber for said funnel and said intercepting means. .Iaddend.