Device and method for changing the reel in an unwinder

Abstract

To obtain the automatic change of the reel in an unwinder, in particular for reels of paper and other materials in web form, operation in which a reel ( 2 ) that is nearly empty is replaced with a new reel ( 2 ′), wherein provision is made to connect a tail portion (LC) of the web of the nearly empty reel ( 2 ) to the head portion (LT) of the web of the new reel ( 2 ′) after overlapping of said ends (LC) and (LT), said overlap step begins along the surface of the new reel 2 ′, right next to the latter.

1 . Method for automatically changing the reel in an unwinder, in particular for reels of paper and other materials in web form, operation in which a reel ( 2 ) that is nearly empty is replaced with a new reel ( 2 ′), wherein provision is made to connect a tail portion (LC) of the web of the nearly empty reel ( 2 ) to the head portion (LT) of the web of the new reel ( 2 ′) after overlapping of said ends (LC) and (LT), characterized in that said overlap step begins along the surface of the new reel  2 ′, right next to the latter. 
   
   
       2 . Method according to  claim 1  characterized in that said ends (LC) and (LT) overlap while both are moving, directed towards a web exit section of the unwinder. 
   
   
       3 . Method according to  claim 1  characterized in that said overlap takes place while at least one of said reels is rotating about the respective axis. 
   
   
       4 . Method according to  claim 3  characterized in that both said reels rotate about their axes before said overlap step begins. 
   
   
       5 . Method according to  claim 1  characterized in that during the substitution of the reel ( 2 ) that is nearly empty with the new reel ( 2 ′) the latter intercepts a tail portion ( 4 ) of reel ( 2 ) that is nearly empty. 
   
   
       6 . Method according to  claim 1  characterized in that an adhesive means ( 14 ) is applied to said head portion (LT) of the web of the new reel ( 2 ′) before the connection thereof with the tail portion ( 4 ) of the reel ( 2 ) that is nearly empty takes place. 
   
   
       7 . Method according to  claim 1  characterized in that a mechanical connection is realized between said portions (LC) and (LT) by means of ply-bonding. 
   
   
       8 . Method according to  claim 1  characterized in that the web ( 4 ) unwound from the reel ( 2 ) that is nearly empty is subject to loosening due to the weight of the new reel ( 2 ′) while the latter is positioned in an operative station (S 1 ) previously engaged by the reel ( 2 ) that is nearly empty and further due to the free and concurrent rotation of the reel ( 2 ) that is nearly empty positioned in a temporary parking station. 
   
   
       9 . Method according to  claim 1  characterized in that the web ( 4 ) unwound from the reel ( 2 ) that is nearly empty is subject to cut at a point upstream of said connection. 
   
   
       10 . Device for automatically changing the reel in an unwinder, in particular for reels of paper and other materials in web form, of the type comprising an unwinding station wherein a reel freely rotates about the longitudinal axis ( 300 ) of the respective core ( 30 ), thus being unwound to feed the respective web material downstream, a temporary parking station (S 2 ) provided upstream of said unwinding station (S 1 ) wherein reels ( 2 ) that are nearly empty are positioned and means for transferring the reels ( 2 ) that are nearly empty from said unwinding station (S 1 ) to said parking station (S 2 ), characterized in that it comprises a plurality of idle rollers or bearings ( 29 ) which are disposed in said parking station (S 2 ) with their axes ( 290 ) parallel to the axis ( 300 ) of the core ( 30 ) of the reel ( 2 ) that is nearly empty. 
   
   
       11 . Device according to  claim 10  characterized in that said rollers or bearings ( 29 ) are provided, in correspondence of said parking station (S 2 ), at the end of a ramp defined by an inclined plane ( 13 ) connecting said unwinding station (S 1 ) with said parking station (S 2 ). 
   
   
       12 . Device according to  claim 10  characterized in that it comprises automatic cutting means disposed and acting between said parking station (S 2 ) and said unwinding station (S 1 ), said cutting means being intended to cut the web ( 4 ) provided by the reel ( 2 ) that is nearly empty. 
   
   
       13 . Device according to  claim 10  characterized in that it comprises pressure means ( 30 ), provided downstream of said unwinding station (S 1 ), indeed to exert a pressure onto glued portions of the webs provided by the reel that is nearly empty and the new reel, said pressure being exerted along the transverse direction of the webs, said portions being a tail portion of the web ( 4 ) unwound from the reel ( 2 ) that is nearly empty and a head portion of the new reel ( 2 ′). 
   
   
       14 . Device according to  claim 10  characterized in that it comprises for mechanically joining the tail portion of the web unwound from the reel ( 2 ) that is nearly empty and the head portion of the new reel. 
   
   
       15 . Device according to  claim 14  characterized in that it means for guiding said tail and head portions directed towards said mechanically joining means. 
   
   
       16 . Device according to  claim 12  characterized in that it comprises a control unit (C) to which said cutting means are connected.