Unwinder and operating method for unwinding web materials from parent reels

Abstract

Method for unwinding web materials from two parent reels (1, 2), wherein a first parent reel (1) in a depletion phase is replaced by a second parent reel (2), wherein during said replacement a first and a second web material (N1, N2) are unwound from both parent reels, wherein before the completion of said replacement the first web material (N1) is joined to the second web material (N2) and then it is cut, wherein the joining of said web materials (N1, N2) is preceded by the insertion of the second web material in an area where the two web materials are joined, and during the step of inserting the second web material in said joining area the second web material is guided on a guide surface (41, 44) which guides it towards the joining area. In said insertion step, the second web material adheres pneumatically to guide surface.

1 . Method for unwinding web materials (N 1 , N 2 ) from two corresponding parent reels ( 1 ,  2 ), wherein a first parent reel ( 1 ) in a depletion phase is replaced by a second parent reel ( 2 ) which takes the place of the first parent reel at the end of the replacement, wherein during said replacement a first and a second web material (N 1 , N 2 ) are unwound from both parent reels, wherein before the completion of said replacement the first web material (N 1 ) is joined to the second web material (N 2 ) and then it is cut, wherein the joining of said web materials (N 1 , N 2 ) is preceded by a step of inserting the second web material (N 2 ) in an area where the two web materials (N 1 , N 2 ) are joined, wherein during the step of inserting the second web material (N 2 ) in said joining area the second web material (N 2 ) is guided on a guide surface ( 41 ,  44 ) which guides it towards said joining area, characterized in that, in said insertion step, the second web material (N 2 ) adheres pneumatically to said guide surface. 
     
     
         2 . Method according to  claim 1  characterized in that, before carrying out said replacement, the second parent reel ( 2 ) is placed in a waiting and temporary unwinding position (P 2 ) above another position (P 1 ) occupied by the first parent reel ( 1 ). 
     
     
         3 . Method according to  claim 1  characterized in that the first parent reel ( 1 ) is rotated by a motorized belt ( 31 ) acting on it by contact in a position (P 1 ) occupied by the latter. 
     
     
         4 . Method according to  claim 1  characterized in that the guide surface ( 41 ,  44 ) consists of motorized belts which, while guiding the second web material (N 2 ) towards said joining area, cause the rotation of the second parent reel ( 2 ) around a respective axis of rotation. 
     
     
         5 . Method according to  claim 1  characterized in that the adhesion of the second web material (N 2 ) to the guide surface ( 41 ,  44 ) is carried out by means of compressed air supplied by nozzles ( 7 ) oriented towards said surface or by suction operated through the guide surface itself by means of a suction box ( 8 ). 
     
     
         6 . Method according to  claim 1  characterized in that said web-like materials are made of paper. 
     
     
         7 . Method according to  claim 1  characterized in that said web-like materials are non-woven fabric webs. 
     
     
         8 . Unwinder configured for unwinding web materials (N 1 , N 2 ) from respective parent reels ( 1 ,  2 ) comprising:
 a structure on which support members adapted to support a first parent reel ( 1 ) and a second parent reel ( 2 ) in different positions are formed, said support members being configured for supporting the parent reels ( 1 ,  2 ) during rotation of the same about respective longitudinal axes;   motorized dragging means configured to control the rotation of said parent reels ( 1 ,  2 ) with a predetermined angular speed around the respective longitudinal axes;   joining means for joining together the web materials (N 1 , N 2 ) unwound from the parent reels ( 1 ,  2 ) when one of them, in a phase of depletion, must be replaced with the other;   means for transferring a parent reel from a waiting position (P 2 ) to an operating position (P 1 ) when the diameter of a parent reel arranged in the operating position (P 1 ) reaches a predetermined minimum value;   means for transferring a parent reel from the operating position (P 1 ) to a removal position (P 3 ) when the other parent reel is transferred from the waiting position (P 2 ) to the operating position (P 1 );   a guide surface ( 41 ,  44 ) configured to guide the web (N 2 ) unwound from the reel ( 2 ) of the waiting position (P 2 ) towards said joining means;   
       characterized in that it further comprises:
 pneumatic means ( 7 ;  8 ) that can be activated to produce, on the web material (N 2 ) unwound from the reel ( 2 ) of the waiting position (P 2 ), a pressure or suction directed towards the guide surface ( 41 ,  44 ) while the latter guides it towards the joining means. 
 
     
     
         9 . Unwinder according to  claim 8  characterized in that said guide surface ( 41 ,  44 ) is a movable surface supported by an arm ( 4 ) controlled to arrange the same guide surface ( 41 ,  44 ) in contact with the reel ( 2 ) of the waiting position (P 2 ) to drag it into rotation around its own axis. 
     
     
         10 . Unwinder according to  claim 8  characterized in that said positions (P 1 , P 2 , P 3 ) are formed by concave supports with the concavity facing upwards, a support ( 5 ) is formed on a carriage ( 50 ) which can be moved alternatively between the waiting position (P 2 ) and the operating position (P 1 ), and a support is formed on another carriage ( 60 ) which can be moved alternately between the removal position (P 3 ) and the operating position (P 1 ). 
     
     
         11 . Unwinder according to  claim 8  characterized in that said pneumatic means are formed by nozzles ( 7 ) fed with compressed air and oriented towards said guide surface ( 41 ,  44 ) or by a suction box ( 8 ) placed on a rear side of the guide surface ( 41 ,  44 ). 
     
     
         12 . Unwinder according to  claim 8  characterized in that said means for joining the web-like materials comprise a ply-bonding unit (M 1 , M 2 ). 
     
     
         13 . Unwinder according to  claim 8  characterized in that it comprises cutting means suitable for cutting the web material unwound from the reel ( 1 ) which occupies the operating position (P 1 ).