Method and apparatus for the production of coreless paper rolls

Abstract

A method and apparatus for the production of coreless paper rolls, including a winding phase on a central spindle of a paper web carried out by a main reel, until the formation of a wound paper roll, a phase of extraction from the wound roll of the spindle by application of a relative axial extraction force between the roll and the spindle, where the winding phase includes a first winding phase of a number of web revolutions on the central spindle performed at a first winding tension that is lower than the next winding tension.

1 . A method for producing coreless paper rolls, comprising:
 a step of winding a paper web onto a central spindle carried out by a main coil, until a wound paper roll is formed, and   a step of extracting the central spindle from the wound paper roll by applying a relative axial extraction force between the wound paper roll and the central spindle,   wherein the winding step comprises a step of first winding the paper web on the central spindle carried out at a first winding tension lower than a subsequent winding tension in order to reduce a friction between the paper web and an external surface of the central spindle and a corresponding axial force necessary to extract the central spindle from an inside of the wound paper roll in the extraction step.   
     
     
         2 . The method according to  claim 1 , wherein the first winding step comprises a pneumatic winding of the paper web on the central spindle. 
     
     
         3 . The method according to  claim 1 , wherein the first winding step comprises a step of rotating the central spindle according to an advancement of the paper web to be wound. 
     
     
         4 . The method according to  claim 1 , wherein the winding step comprises a preliminary step of applying glue to the central spindle. 
     
     
         5 . The method according to  claim 1 , comprising a transfer step of an extracted spindle at the winding step to a new winding step, wherein the extraction, transfer and winding steps are performed in a cyclical manner. 
     
     
         6 . The method according to  claim 1 , wherein the extraction step takes place by retaining the central spindle in position and acting axially on the paper winding. 
     
     
         7 . The method according to  claim 6 , wherein the central spindle is a hollow spindle and the retaining step is actuated by a retaining member acting by spherical radial protrusions impinging on an inner surface of an axial end portion of the central spindle. 
     
     
         8 . The method according to  claim 1 , wherein the transfer step comprises a step of accumulation of a number of extracted rolls. 
     
     
         9 . An apparatus for a production of coreless paper rolls, comprising
 a rewinding machine for winding a web wound by a main coil around a spindle, and   an extraction device configured to receive a wound roll from the rewinding machine to extract the spindle,   wherein the rewinding machine comprises:   pneumatic means for the first winding of the web on the spindle in transit through a winding channel   movement means of the spindle comprising a distribution of belts movable in a direction according to a direction of advancement of the web and extended in contact with the spindle to impart to the spindle in transit in the winding channel a rotary motion in accordance with the direction of advancement of the web and of controlled speed to obtain a first winding tension lower than a subsequent winding tension, in order to reduce a friction between the web and an external surface of the spindle.   
     
     
         10 . The apparatus according to  claim 9 , comprising a transfer device configured to receive extracted spindles from an extractor device and feed the extracted spindles to the rewinding machine for an execution of a new winding. 
     
     
         11 . The apparatus according to  claim 9 , wherein the extraction device comprises roll centering means comprising a first fixed inclined surface and a second inclined surface movable between a lowered roll receiving position and a raised roll centering position due to a convergence of the first fixed inclined surface and the second inclined surface. 
     
     
         12 . The apparatus according to  claim 9 , wherein the extraction device comprises a gripping unit to hold the spindle to be extracted in position and a sliding pusher to push the wound roll axially and move the wound roll with respect to the spindle until the wound roll is extracted. 
     
     
         13 . The apparatus according to  claim 9 , wherein the spindle is a hollow spindle and the gripping unit comprises an expansion restraint insertable within the spindle and comprising spherical radial protrusions impinging on an inner surface of the spindle. 
     
     
         14 . The apparatus according to  claim 9 , wherein the gripping unit is vertically adjustable to adapt to different heights of the spindle. 
     
     
         15 . The apparatus according to  claim 9 , wherein the extraction device comprises a vertically movable cradle for receiving the extracted spindle and lowering down to a chute below the spindle towards a transfer channel for outputting the spindles from the extractor device. 
     
     
         16 . The apparatus according to  claim 9 , wherein the transfer device comprises a repository for accumulating extracted spindles. 
     
     
         17 . The apparatus according to  claim 16 , wherein the transfer device comprises a plurality of supports for the spindles moved by a chain or belt transfer apparatus mounted on pulleys and moved by motors along a portal support structure extended from a spindle receiving position to the repository. 
     
     
         18 . The method according to  claim 2 , wherein the first winding step comprises a step of rotating the central spindle according to an advancement of the paper web to be wound. 
     
     
         19 . The method according to  claim 2 , wherein the winding step comprises a preliminary step of applying glue to the central spindle. 
     
     
         20 . The method according to  claim 3 , wherein the winding step comprises a preliminary step of applying glue to the central spindle.