Winding or rewinding machine for producing rolls of web material around a winding spindle and relative winding method

Abstract

A winding or rewinding machine to wind a web material (N) and form a roll (R) around a winding spindle ( 13 ) is disclosed, comprising: at least a roller ( 5 ) in contact with said winding spindle in the initial phase of winding the web material around the spindle; a transverse cutting element ( 19 ) to cut the web material when a roll has been wound and form an initial free end to wind a subsequent roll around a new winding spindle. Moreover, at least an electrostatic bar ( 21 ) to electrostatically charge the web material is also provided. The roller ( 5 ) in contact with the spindle is made at least partially in non-electrically conductive material.

1 . A winding or rewinding machine to wind a web material (N) and form a roll (R) around a winding spindle ( 13 ;  45 ;  103 ), comprising: at least a roller ( 5 ;  73 ;  109 ) in contact with said winding spindle in the initial phase of winding the web material around the spindle; a transverse cutting element ( 19 ;  69 ;  117 ) to cut the web material at the end of winding one roll and form a initial free end to wind a subsequent roll around a new winding spindle, said initial free end being inserted between said roller and said winding spindle, characterized in that a least an electrostatic bar ( 21 ;  71 ;  131 ) is provided to electrostatically charge the web material and in that said roller ( 5 ;  73 ;  109 ) in contact with the spindle is made at least partially of non-electrically conductive material.  
     
     
         2 . Machine as claimed in  claim 1 , characterized in that said roller ( 5 ;  73 ;  109 ) comprises a cylindrical wall made completely of non-electrically conductive material.  
     
     
         3 . Machine as claimed in  claim 1  or  2 , characterized in that said roller is a winding roller ( 5 ;  109 ) which remains in contact with the roll (R) being formed around said spindle substantially for the entire winding cycle of the roll.  
     
     
         4 . Machine as claimed in  claim 1 ,  2  or  3 , characterized in that it comprises two winding rollers (( 3 ,  5 ) forming a winding cradle ( 7 ) in which said winding spindle ( 13 ) is inserted and on which said roll is formed, at least one ( 5 ) of said winding rollers being formed at least partially in non-electrically conductive material.  
     
     
         5 . Machine as claimed in  claim 4 , characterized in that said electrostatic bar ( 21 ) and said transverse cutting element ( 19 ) are mounted on an assembly ( 17 ) oscillating around the axis of the first ( 3 ) of said winding rollers ( 3 ,  5 ), at least the second ( 5 ) of said winding rollers being made at least partially of non-electrically conductive material.  
     
     
         6 . Machine as claimed in  claim 4  or  5 , characterized in that the web material is fed to the winding cradle ( 7 ) passing along a path that crosses a nip formed of said two winding rollers ( 3 ,  5 ).  
     
     
         7 . Machine as claimed in  claim 3 , characterized in that it comprises a support ( 43 ;  101 ) for said winding spindle ( 45 ;  103 ), said winding spindle and said roll being formed around said spindle being maintained in rotation by said winding roller ( 51 ;  109 ), around which the web material is driven.  
     
     
         8 . Machine as claimed in  claim 7 , characterized by a moving assembly ( 67 ) carrying said transverse cutting element ( 69 ) and said electrostatic bar ( 71 ), said assembly oscillating around an axis parallel to the axis of rotation of said winding roller ( 51 ) to cut the web material and fasten the web material around said winding spindle.  
     
     
         9 . Machine as claimed in  claim 7 , characterized by a moving assembly ( 115 ) carrying said transverse cutting element ( 117 ) and said electrostatic bar ( 131 ), said assembly performing a complete rotation around an axis parallel to the axis of rotation of said winding roller ( 109 ) to cut the web material and fasten the web material around said winding spindle.  
     
     
         10 . Machine as claimed in  claim 8  or  9 , characterized in that said moving assembly ( 67 ;  115 ) carries a pair of guiding rollers ( 80 ,  81 ;  125 ,  127 ).  
     
     
         11 . Machine as claimed in  claim 10 , characterized in that said transverse cutting element ( 117 ) is positioned between said guiding rollers ( 125 ,  127 ) carried by said moving assembly ( 115 ).  
     
     
         12 . Machine as claimed in  claim 1  or  2 , characterized in that it comprises a support ( 43 ) for said winding spindle ( 45 ), a winding roller ( 51 ) in contact with said roll to maintain the roll in rotation while it is being formed, a moving assembly ( 67 ) carrying said electrostatic bar ( 71 ), said cutting element ( 69 ) and said roller ( 73 ) formed at least partially in non-electrically conductive material.  
     
     
         13 . Machine as claimed in  claim 12 , characterized in that said roller ( 73 ) formed at least partially in non-electrically conductive material is provided with a movement in relation to the moving assembly which draws it towards and moves it away from the winding spindle.  
     
     
         14 . Machine as claimed in  claim 13 , characterized in that said moving assembly ( 67 ) carries a first actuator ( 79 ) to operate said transverse cutting element ( 69 ) and a second actuator ( 77 ) to draw said roller ( 73 ) towards and move it away from the winding spindle.  
     
     
         15 . Machine as claimed in one or more of the previous claims, characterized in that said roller formed at least partially in non-electrically conductive material has a cylindrical surface constituted by a reinforced synthetic material.  
     
     
         16 . Method to produce rolls of web material wound around winding spindles, comprising the phases of: 
 winding a first roll of web material around a first winding spindle;    bringing a second winding spindle in contact with the web material;    cutting the web material, in proximity to said second winding spindle to form an initial free end and a final free end of web material;    winding the initial free end of the web material around said second spindle and starting to wind a second roll, said web material being retained, in proximity to said initial free end, between said second winding spindle and said roller;    characterized in that said roller is made in non-electrically conductive material.    
     
     
         17 . Method as claimed in  claim 16 , characterized in that said roller in non-electrically conductive material is a winding roller, said rolls being wound with a peripheral winding system.  
     
     
         18 . Method as claimed in  claim 16  or  17 , characterized by cutting the web material before inserting the free end between said second spindle and said roller in non-electrically conductive material.  
     
     
         19 . Method as claimed in  claim 16  or  17 , characterized by engaging the web material between said second winding spindle and said roller before cutting the web material.