Core feeding method in a rewinding machine for making logs of sheet material

Abstract

A rewinding method for a web ( 1 ) of sheet material for making a log ( 2 a ) wound on a core ( 20 a, 20 b, 20 c ) in a winding zone ( 4 ) formed between an upper winding roller ( 5 ) and a lower winding roller ( 6 ), in particular for the production of rolls of toilet paper, rolls of all purpose tissue paper or non woven fabric for household use, industrial rolls and the like. Upstream of the winding zone ( 4 ) a cradle ( 21,26 ) is provided for feeding the core ( 20 b ) connected to the support ( 29 ) of the lower roller and located beneath the upper winding roller ( 5 ). At least a portion ( 21 ) of the cradle ( 21,26 ) is movable with respect to the support ( 29 ) of the lower roller ( 5 ) and is capable of lowering or rising towards/away from the upper winding roller ( 5 ). For each step of feeding a core ( 20 b ), the movable portion ( 21 ) can be displaced from a first position of load of the core ( 20 b ) to a second position wherein the core ( 20 b ) contacts the upper roller ( 5 ). When the upper roller ( 5 ) contacts the core ( 20 b ) for reaching the winding zone ( 4 ) it moves first on the movable portion ( 21 ) and then on a fixed portion ( 26 ) of the cradle that is integral to the support ( 29 ) wherein the axle rotates of the lower roller ( 5 ).

1 . Rewinding method for a web ( 1 ) of sheet material for making a log ( 2   a ) wound on a core ( 20   a , 20   b , 20   c ), in particular for the production of rolls of toilet paper, rolls of all purpose tissue paper or non woven fabric for household use, industrial rolls and the like, comprising the steps of: 
 feeding a web of paper ( 1 ) in a winding zone ( 4 ) formed between an upper winding roller ( 5 ) and a lower winding roller ( 6 );    arranging upstream of the winding zone ( 4 ) a cradle ( 21 , 26 ) for feeding the core ( 20   b ) connected to said lower roller, said cradle ( 21 , 26 ) being located beneath the upper winding roller ( 5 ) and extending from a core feeding zone ( 20   b ) up to said lower winding roller ( 6 ); 
 characterised in that at least a portion ( 21 ) of said cradle ( 21 , 26 ) is movable with respect to the support ( 29 ) of said lower roller ( 5 ) and is capable of lowering or rising towards/away from said upper winding roller ( 5 ).  
   
     
     
         2 . Method according to  claim 1 , wherein, for each step of feeding a core ( 20   b ), said at least one portion ( 21 ) of said cradle that is movable with respect to the support ( 29 ) of said lower roller ( 6 ) can be displaced from a first position of load of said core ( 20   b ) to a second position wherein said core ( 20   b ) contacts said upper roller ( 5 ).  
     
     
         3 . Method according to  claim 1 , wherein in its movement of lowering/rising ( 24 , 25 ) the movable portion ( 21 ) rotates ( 23 ) about a pivot ( 29 ) concentric to said lower roller ( 5 ).  
     
     
         4 . Method according to  claim 1 , wherein said core ( 20   b ) for reaching said winding zone ( 4 ) even if remaining in contact with said upper roller ( 5 ) moves first on said at least one movable portion ( 21 ) and then on a fixed portion ( 26 ) of said cradle that is integral to the support ( 29 ) wherein the axle rotates of said lower roller ( 5 ).  
     
     
         5 . Method according to  claim 1 , wherein said core ( 20   b ) for reaching said winding zone ( 4 ) even if remaining in contact with said upper roller ( 5 ) is pushed by said cradle ( 21 , 26 ) against said upper roller ( 5 ) in a resilient way.  
     
     
         6 . Method according to  claim 1 , wherein said core ( 20   b ) is put on said cradle when said movable portion ( 21 ) is in lowered position, rolling on a downhill portion ( 21   b ) of said movable portion up to reaching a peeping stop element ( 27 ).  
     
     
         7 . Method according to  claim 1 , wherein the steps are provided of: 
 rising ( 24 , 25 ) of said core ( 20   b ) by means of said movable portion ( 21 ) up to a position approached to the upper roller ( 5 ) without that there is contact with the latter,    starting from said approached position, further short rising movement ( 24 , 25 ) of said core ( 20   b ) up to be pushed against said upper winding roller ( 5 ), whereby the latter can bring it forward towards the winding zone ( 4 )    
     
     
         8 . Method according to  claim 1 , wherein the contact of the core ( 20   a , 20   b , 20   c ) same against the upper winding roller ( 5 ) allows the tearing of the web ( 1 ) along a line of transversal perforation ( 31 ) that is located between the core ( 20   b ) and said winding zone ( 4 ), a step being provided of stretching the web ( 1 ) between said core ( 20   b ) and said winding zone.  
     
     
         9 . A rewinding machine of a web ( 1 ) for making a log ( 2   a ) wound on a core ( 20   a , 20   b , 20   c ), in particular for the production of rolls of toilet paper, rolls of all purpose tissue paper or non woven fabric for household use, industrial rolls and the like, comprising: 
 means for feeding and dragging ( 3 , 8 ) a web ( 1 ) of paper;    a winding zone ( 4 ) where a log is wound ( 2   a ) downstream of the means for feeding ( 3 , 8 ) the web ( 1 );    means for feeding ( 22 ) the core ( 20 );    a cradle ( 21 , 26 ) for feeding the core ( 20   b ) arranged upstream of the winding zone ( 4 ), said cradle ( 21 ) being located beneath the upper winding roller ( 5 ) and extending between said means for feeding ( 22 ) of the core ( 20 ) up to said lower winding roller ( 6 ); 
 characterized in that it comprises 
 means for lowering/rising ( 23 , 24 , 25 ) at least one movable portion ( 21 ) of said cradle ( 21 , 26 ) with respect to said lower roller ( 6 ) towards/away from said upper roller ( 5 ).  
 
   
     
     
         10 . Apparatus according to  claim 9 , wherein said cradle ( 21 , 26 ) has a resilient surface for adapting to the passage of said core ( 20   b ) when pushing it against said upper roller ( 5 ).  
     
     
         11 . Apparatus according to  claim 9 , wherein said cradle ( 21 , 26 ) has a curved surface with concavity oriented towards said upper roller ( 5 ).  
     
     
         12 . Apparatus according to  claim 9 , wherein said means for lowering/rising ( 24 , 25 ) said cradle ( 21 ) towards/away from said upper winding roller ( 5 ) are operatively connected to an arm ( 23 ) pivoted to the support ( 29 ) wherein the axle rotates of said lower winding roller ( 6 ).  
     
     
         13 . Apparatus according to  claim 9 , wherein said cradle has fixed portion ( 26 ) integral to the support ( 29 ) wherein the axle rotates of said lower roller ( 5 ) at the end of said movable portion ( 21 ), said movable portion ( 21 ) cooperating with said fixed portion ( 26 ) in order to form a single surface of support for core ( 20   b ).  
     
     
         14 . Apparatus according to  claim 9 , wherein starting from the edge of said means for feeding said movable portion ( 21 ) has a downhill portion ( 21   b ) and a peeping stop element ( 27 ).