Assembly for ultrasound sealing continuous tubular strips

Abstract

A rotary assembly, for FFS (Form, Fill and Seal) machines, for ultrasound sealing a continuous tubular strip housing an orderly succession of products and travelling along a feed path extending through the sealing station; the rotary assembly having two rotors, which are located on opposite sides of the feed path, and rotate in opposite directions about respective axes; and at least one of the two rotors being fitted with at least one ultrasound sealing device, which cooperates at the sealing station with a corresponding anvil fitted to the other rotor with the interposition of elastic members.

1 - 14 . (canceled) 
     
     
         15 . A rotary ultrasound sealing assembly, which is located at a sealing station ( 4 ) to ultrasound seal a continuous tubular strip ( 2 ) housing an orderly succession of products ( 3 ) and travelling along a feed path (P) extending through the sealing station ( 4 ); the rotary sealing assembly ( 5 ) comprising:
 two rotors ( 8 ,  9 ), which are located on opposite sides of the feed path (P), rotate in opposite directions about respective axes ( 10 ,  11 ), and have respective pitch surfaces ( 12 ,  13 ) tangent to each other and to the feed path (P);   at least one ultrasound sealing device ( 20 ) fitted to at least one of the two rotors ( 8 ,  9 );   a corresponding anvil ( 47 ) which cooperates, at the sealing station ( 4 ), with the sealing device ( 20 ) and is fitted to the other of the two rotors ( 8 ,  9 ); and   elastic means ( 56 ) interposed between the anvil ( 47 ) and the relative rotor ( 8 ;  9 );   the rotary sealing assembly is characterized in that:   the anvil ( 47 ) comprises hollow portions ( 53 ) open towards the relative rotor ( 8 ;  9 );   each hollow portion ( 53 ) has an end wall ( 55 ) closing it outwardly; and relevant elastic means ( 56 ) are housed inside a relative hollow portion ( 53 ), and are compressed between the relative rotor ( 8 ;  9 ) and the relative end wall ( 55 ).   
     
     
         16 . A rotary sealing assembly as claimed in  claim 15 , wherein the elastic means ( 56 ) are made of metal. 
     
     
         17 . A rotary sealing assembly as claimed in  claim 16 , wherein the elastic means comprise metal helical springs ( 56 ). 
     
     
         18 . A rotary sealing assembly as claimed in  claim 17 , wherein said springs ( 56 ) extend substantially radially with respect to the relative rotor ( 8 ;  9 ). 
     
     
         19 . A rotary sealing assembly as claimed in  claim 15 , wherein the hollow portions ( 53 ) are two in number, and define respective longitudinal end portions of the anvil ( 47 ). 
     
     
         20 . A rotary sealing assembly as claimed in  claim 15 , and comprising two sealing devices ( 20 ) having respective aligned active surfaces ( 25 ); the anvil ( 47 ) having a contrast surface ( 49 ) extending longitudinally to cooperate with both said active surfaces ( 25 ) at the sealing station ( 4 ). 
     
     
         21 . A rotary sealing assembly as claimed in  claim 15 , wherein each said rotor ( 8 ; 9 ) comprises a given number of sealing devices ( 20 ), and an equal number of anvils ( 47 ); each sealing device ( 20 ) having a respective active surface ( 25 ); each anvil ( 47 ) having a respective contrast surface ( 49 ); and said active ( 25 ) and contrast ( 49 ) surfaces defining respective alternating portions equally spaced along the pitch surface ( 12 ;  13 ) of the relative rotor ( 8 ;  9 ). 
     
     
         22 . A rotary sealing assembly as claimed in  claim 21 , wherein, along the pitch surface ( 12 ;  13 ) of the relative rotor ( 8 ;  9 ), each active surface ( 25 ) is located diametrically opposite another active surface ( 25 ). 
     
     
         23 . A rotary sealing assembly as claimed in  claim 21 , wherein, along the pitch surface ( 12 ;  13 ) of the relative rotor ( 8 ;  9 ), each active surface ( 25 ) is located diametrically opposite a contrast surface ( 49 ). 
     
     
         24 . A rotary sealing assembly as claimed in  claim 15 , and comprising a number of sealing devices ( 20 ) and a number of anvils ( 47 ); the sealing devices ( 20 ) all being supported by one ( 8 ) of the rotors ( 8 ,  9 ), and the anvils ( 47 ) all being supported by the other ( 9 ) of the rotors ( 8 ,  9 ). 
     
     
         25 . A rotary sealing assembly as claimed in  claim 15 , wherein at least one of the two rotors ( 8 ,  9 ) is fitted rigidly with a blade ( 42 ). 
     
     
         26 . A rotary sealing assembly as claimed in  claim 15 , wherein at least one of the two rotors ( 8 ,  9 ) is fitted elastically with a blade ( 42 ) fixed rigidly to the anvil ( 47 ); the elastic means ( 56 ) being interposed between the anvil ( 47 ) and the relative rotor ( 8 ;  9 ). 
     
     
         27 . An FFS machine comprising a rotary ultrasound sealing assembly ( 5 ) as claimed in  claim 15 .