Forming unit for producing sealed packages from a tube of sheet packaging material filled with a pourable food product

Abstract

There is described a forming unti ( 1 ) for producing sealed packages ( 2 ) from a tube ( 3 ) of sheet packaging material fed along a feed path (A) and filled with a pourable food product. The unit ( 1 ) has jaw means ( 6, 6 ′) acting cyclically on the tube ( 3 ) to grip and seal it at equally spaced cross sections defining opposite sealing bands ( 15 ) of the packages ( 2 ); interacting means ( 23; 16 ) interacting with the tube ( 3 ) and fitted movably to the jaw means ( 6, 6 ′); and actuating means ( 27; 40 ) for operating the interacting means ( 23; 16 ) and mounted entirely on the jaw means ( 6, 6 ′).

1 . A forming unit for producing sealed packages from a tube of sheet packaging material fed along a feed path and filled with a pourable food product, said unit comprising jaw means acting cyclically on said tube to grip and seal it at equally spaced cross sections defining opposite sealing bands of said packages; interacting means interacting with said tube and fitted movably to said jaw means; and actuating means for operating said interacting means; wherein said actuating means are mounted entirely on said jaw means.  
   
   
       2 . A unit as claimed in  claim 1 , wherein said jaw means comprise at least two forming assemblies, each defined by a pair of jaws cooperating cyclically with each other and with said tube.  
   
   
       3 . A unit as claimed in  claim 1 , wherein said interacting means comprise traction means for exerting pull on said tube of packaging material to correct the travel of said tube along said feed path.  
   
   
       4 . A unit as claimed in  claim 3 , wherein said traction means comprise two movable members carried by one of said jaws of each said forming assembly and interacting on opposite sides with said tube.  
   
   
       5 . A unit as claimed in  claim 4 , wherein said movable members comprise respective pins rotating with respect to the relative said jaw; and respective tabs carried eccentrically by said pins.  
   
   
       6 . A unit as claimed in  claim 4 , wherein, for each said one of said jaws, said actuating means comprise a first control actuator, and transmission means interposed between said first actuator and said movable members.  
   
   
       7 . A unit as claimed in  claim 6 , wherein each said first actuator comprises a first output member movable in a direction crosswise to said feed path of said tube and to the axes of said pins of the relative said movable members; and in that said transmission means comprise, for each said one of said jaws, a lever, which has a connecting portion hinged to said first output member of the relative said first actuator, and defines two fastening portions to which are hinged respective arms for activating the relative said movable members and carried eccentrically by the respective said pins.  
   
   
       8 . A unit as claimed in  claim 1 , wherein said interacting means comprise box means enclosing portions of said tube of predetermined shape and volume and eventually defining said packages.  
   
   
       9 . A unit as claimed in  claim 8 , wherein, for each said forming assembly, said box means comprise a pair of boxes connected movably to the respective said jaws and cooperating with each other to define a cavity of predetermined shape and volume and enclosing said tube.  
   
   
       10 . A unit as claimed in  claim 9 , wherein, for each said forming assembly, said actuating means comprise push means activated selectively to grip together the relative said boxes.  
   
   
       11 . A unit as claimed in  claim 10 , wherein said push means comprise, for each said jaw, a second control actuator having a second output member movable in a direction crosswise to said feed path of said tube; and a toggle mechanism, which extends crosswise to the travel direction of said second output member, is interposed between the relative said jaw and the relative said box, and is activated by the second output member.