Flexible winding mandrel with core segments for producing rolls of wound paper

Abstract

A flexible mandrel is provided for holding cores or core segments so that a roll of sheet material can be wound on the core segments in a winding machine. The mandrel and core segments are coupled through elastic interference between the mandrel and the core segments so that the core segments are arranged either adjacent to each other or spaced apart. A method for producing rolls of sheet material on the novel combination of mandrel and core segments feeds cores in an apparatus, transversely cuts the cores to form portions of core or core segments, feeds a flexible mandrel into the core segments for supporting and maintaining the axial position of the core segments. Coupling is by elastic interference between the flexible mandrel and the core segments to form an assembly in which the core segments are arranged on the mandrel spaced apart or adjacent one to the other.

1 . A combination of an elongated flexible and elastic mandrel and a plurality of tubular core segments for use in a winding machine for winding a roll of sheet material over the core segments, said mandrel having an outer surface, said core segments being retained on the outer surface of the mandrel by elastic interference between the mandrel and the core segments. 
     
     
         2 . The structure of  claim 1  in which said mandrel is tubular. 
     
     
         3 . The structure of  claim 1  in which said mandrel is substantially tubular and is provided with a longitudinally extending opening which provides the mandrel with a generally C-shaped transverse cross section. 
     
     
         4 . The structure of  claim 3  in which the generally C-shaped cross section of the mandrel has a generally C-shaped wall, the thickness of the wall being greater adjacent said longitudinally extending opening. 
     
     
         5 . The structure of  claim 3  in which said mandrel is provided with a plurality of holes. 
     
     
         6 . The structure of  claim 1  in which said mandrel is substantially tubular and is provided with a longitudinally extending split which provides a transverse cross section of the mandrel with a pair of end portions, the end portions overlapping. 
     
     
         7 . The structure of  claim 1  in which said mandrel has a generally star-shaped cross section which is provided by a plurality of curved flutes. 
     
     
         8 . The structure of  claim 1  in which said mandrel is substantially tubular and is formed by a coiled sheet having a pair of ends, the sheet being spirally wrapped so that the ends overlap other portions of the sheet. 
     
     
         9 . The structure of  claim 1  in which said mandrel has a generally tubular wall and a plurality of projections which extend outwardly from the wall and engage the core segments. 
     
     
         10 . The structure of  claim 1  in which the mandrel is formed from rigid PVC. 
     
     
         11 . The structure of  claim 1  in which the mandrel is formed from HDPE. 
     
     
         12 . The structure of  claim 1  in which the mandrel is formed from polypropylene. 
     
     
         13 . A method for the production of rolls of sheet material with split cores on a flexible mandrel in a winding machine comprising the steps of:
 providing tubular cores;   transversely cutting the cores to form portions of core;   feeding a flexible mandrel into the core portions;   coupling by elastic interference between said flexible mandrel and said core portions to form an assembly in which said core portions are arranged on said mandrel;   moving and feeding of said assembly to a winding machine to produce a log of sheet material;   extracting the flexible mandrel from the log; and   cutting the log into rolls.   
     
     
         14 . The method according to  claim 13  in which the core portions on the mandrel are adjacent to each other. 
     
     
         15 . The method according to  claim 13  in which the core portions on the mandrel are spaced apart. 
     
     
         16 . The method according to  claim 13 , characterized in that the coupling between the mandrel and the core portions is performed by fitting said core portions on the mandrel along the entire longitudinal development of the mandrel by means of a relative flow of the core portions coaxially to the mandrel with said mandrel elastically deformed. 
     
     
         17 . The method according to  claim 13 , characterized in that in the coupling between the mandrel and the core portions the radial force exerted by the elastic return of the mandrel determines an action of pressure on the internal side surface of the core portions suitable for preventing axial displacements of core portions. 
     
     
         18 . The method according to  claim 13 , wherein the cutting of the log into rolls takes place by performing the cut between core portions in such a way that each roll has spaced-apart core portions. 
     
     
         19 . An apparatus for the production of rolls of sheet material with split cores on a flexible mandrel in a winding machine, comprising:
 a first processing station and a second processing station longitudinally developed and arranged in line, with said first processing station comprising means for feeding of the cores to the second processing station, the second processing station comprising means for moving and cutting in masked time of said core into portions of core, with said first processing station and second processing station comprising, likewise, co-operating means of coupling between a flexible mandrel placed in said first processing station and the core portions of the core to form an assembly wherein said portions of core are arranged on said flexible mandrel;   means for feeding said assembly to a winding machine for the production of a log;   means for extracting of the flexible mandrel from the log;   means for cutting the log into rolls.   
     
     
         20 . The apparatus according to  claim 19 , wherein said means for feeding of the cores to the second processing station are defined by a conveyor belt subtended between two opposite shoulders of the support structure or frame of the first processing station. 
     
     
         21 . The apparatus according to  claim 19 , characterized in that the means of moving and cutting in masked time comprise a turret rotating with respect to a longitudinal axis, arranged between two ends or opposite shoulders of the frame or support structure of said second processing station and comprising three positions of processing defined by a first position suitable for loading the central core coming from the first processing station with said core fitted on a support shaft, a second position or cutting position suitable for performing cutting of the core into portions of core and a third position or position of unloading for the moving of the portions of core in the direction of the first processing station. 
     
     
         22 . The apparatus according to  claim 21 , characterized in that the second position or cutting position of the turret comprises a plurality of cutting heads restrained with respect to a cross member fixed between the opposite shoulders of the frame of the second processing station and arranged parallel to and equidistant one from the other. 
     
     
         23 . The apparatus according to  claim 21 , characterized in that the means of coupling between the mandrel and the core portions of the core comprise a conveyor assembly longitudinally arranged between the opposite shoulders of the first processing station, a motor roller or wheel fixed to the second processing station, with said conveyor and motor roller co-operating to translate and extract the portions of core from the support shaft at the third processing position of the rotating turret and fit them equally distanced one from the other on the mandrel and, further, a means of linear actuation fixed to the frame or support structure of said first processing station and suitable for aligning axially the mandrel with respect to the core divided into portions of core. 
     
     
         24 . The apparatus according to  claim 23 , characterized in that the conveyor assembly comprises two superimposed motorized belts, respectively, an upper motorized belt and a lower motorized belt, the upper conveyor belt fixed with respect to the frame of the first processing station and the lower motorized belt movable towards/away relatively to the upper motorized belt, each of said upper and lower conveyor belts being provided with elements or inserts in rubber suitable for embracing the core portions of the core winding them and taking them from the support shaft and to fit them on the mandrel placed in intermediate position between said upper conveyor belt and lower conveyor belt. 
     
     
         25 . Apparatus according to  claim 23 , wherein said means of cutting of the log are suitable for cutting on the middle lines of the core portions in such a way as to obtain rolls having a split core with an empty central part. 
     
     
         26 . Apparatus according to  claim 19 , characterized in that said flexible mandrel is made in polymeric material and has a substantially tubular development with an opening longitudinally developed for the entire length of the mandrel to define a “C” shape with an external diameter greater with respect to the internal diameter of the core. 
     
     
         27 . The apparatus according to  claim 19 , characterized in that the flexible mandrel has a closed section, substantially circular. 
     
     
         28 . The apparatus according to  claim 19 , characterized in that the mandrel has a section profile of the star type with three or more points. 
     
     
         29 . The apparatus according to  claim 19 , characterized in that the flexible mandrel is made in two different materials to define, respectively, a rigid internal casing with support function and made in steel, aluminum or composite material and an external casing made of plastic material of the polyurethane type or similar foam material with the function of performing an action of pressure suitable for avoiding axial displacements of the core portions of the core.