Core gluing device for a rewinding machine and related method

Abstract

A core gluing device for a rewinding machine comprises a conveyor ( 1 ) designed to convey cores ( 10 a, 10 b, 10 c ) along a core conveying surface (A-A), a gluing unit ( 2 ) comprising a first gluing roller ( 22 ) which picks up the glue from a glue container ( 20 ) and a second gluing roller ( 26 ) opposed to the first gluing roller, so that each core ( 10 a, 10 b, 10 c ) can pass between the two gluing rollers ( 22, 26 ) for application of a trace of glue ( 100 b, 100 c ) on it. The gluing rollers ( 22, 26 ) are driven at different speeds to control the width of the trace of glue to be applied to the core, and positioning devices ( 4 ) are provided, arranged downstream of the gluing devices ( 2 ) and upstream of a log winding unit ( 6 ) of the rewinding machine for the correct positioning of the core ( 10 c ) with the related trace of glue ( 100 c ), before insertion between the winding rollers.

1 . A core gluing device for a rewinding machine, comprising: 
 conveying means designed to convey cores along a core conveying surface, a gluing unit comprising a first gluing roller which picks up the glue from a glue container and a second gluing roller opposed to said first gluing roller, so that each core can pass between said two gluing rollers to receive a trace of glue, and    positioning devices arranged downstream of said gluing devices and upstream of a winding unit of the rewinding machine for a correct positioning of a core with the related trace of glue before insertion between the winding rollers of the winding unit.    
   
   
       2 . The device of  claim 1  in which said first and second gluing rollers can be driven at different speeds in order to control the width of the trace of glue to be applied on the core.  
   
   
       3 . The device of  claim 1  in which said first and second gluing rollers are counter-rotating and rotate in the core feed direction.  
   
   
       4 . The device of  claim 1  in which said first and second gluing rollers rotate in the same rotation direction.  
   
   
       5 . The device of  claim 1  in which said first and second gluing rollers are rotated by independent motorizations.  
   
   
       6 . The device of  claim 1  including gluing elements fitted on said first gluing roller to pick up the glue from the glue container and to apply it on the cores.  
   
   
       7 . The device of  claim 6  including three of said gluing elements arranged equidistant at an angle of approximately 120° on the circumference of said first gluing roller.  
   
   
       8 . The device of  claim 6  including scraper devices designed to scrape the excess glue from said gluing elements before they reach the core gluing position.  
   
   
       9 . The device of  claim 1  in which said first gluing roller and said glue container are arranged below the core conveying surface and said second gluing roller is arranged above the core conveying surface.  
   
   
       10 . The device of  claim 9  in which the line connecting the center of said first and second gluing rollers is substantially square to the conveying surface and the center distance is adjustable according to the diameter of the cores to be glued.  
   
   
       11 . The device of  claim 1  in which said first gluing roller is rotated step-by-step.  
   
   
       12 . The device of  claim 1  in which said positioning devices comprise a first and a second positioning roller opposed to each other.  
   
   
       13 . The device of  claim 12  in which said first and second positioning rollers are counter-rotating and rotate in the core feed the direction.  
   
   
       14 . The device of  claim 12  in which said first and second positioning rollers are made to rotate in the same rotation direction.  
   
   
       15 . The device of  claim 12  in which said first and second positioning rollers are rotated by independent motorizations.  
   
   
       16 . The device of  claim 12  in which said first and second positioning rollers are rotated by the same motorization.  
   
   
       17 . The device of  claim 12  in which the upper gluing roller and the upper positioning roller are rotated by the same motorization.  
   
   
       18 . A method for gluing cores in a rewinding machine comprising the following steps: 
 conveying tubular cores toward a gluing unit comprising a first gluing roller which picks up the glue from a glue container and a second gluing roller opposed and parallel to said first gluing roller,    applying a trace of glue on each core that passes between said two gluing rollers, and    rotating a core so that the trace of glue thereon is correctly positioned before insertion between the winding rollers of a winding unit.    
   
   
       19 . The method of  claim 18  in which, during application of the glue on a core, said first and second gluing rollers are driven at different speeds in order to control the width of the trace of glue.  
   
   
       20 . The method of  claim 18  in which said rotation of the core is obtained by means of a pair of opposed positioning rollers.