Roll product comprising a core, and a method and an apparatus for its manufacture

Abstract

A roll product consists of a band-shaped web of material having a first end, a second end and a hollow cylindrical core onto which the band-shaped web of material is wound. The hollow cylindrical core has a longitudinal direction and a radial direction. The hollow cylindrical core comprises an inner surface, an outer surface, and at least one protuberance protruding outwardly from the outer surface, principally in the radial direction of the hollow cylindrical core, for mechanically and releasably engaging and holding the first end of the band-shaped web of material. The protuberance is an integral part of the hollow cylindrical core and comprises the inner surface and the outer surface of the hollow cylindrical core.

1 . A roll product comprising a band-shaped web of material having a first end and a second end and a hollow cylindrical core onto which the band-shaped web of material is wound, the hollow cylindrical core having a longitudinal direction and a radial direction, the hollow cylindrical core comprising an inner surface, an outer surface, and at least one protuberance protruding outwardly from the outer surface of the hollow cylindrical core, principally in the radial direction of the hollow cylindrical core, for mechanically and releasably engaging and holding the first end of the band-shaped web of material, the protuberance being an integral part of the hollow cylindrical core and comprising the inner surface and the outer surface of the hollow cylindrical core.  
     
     
         2 . A roll product according to  claim 1 , wherein a plurality of protuberances are arranged uniformly on the casing of the hollow cylindrical core.  
     
     
         3 . A roll product according to  claim 1 , wherein a plurality of protuberances are arranged irregularly on the casing of the hollow cylindrical core.  
     
     
         4 . A roll product according to  claim 1 , wherein the protuberance consists of at least one protruding element.  
     
     
         5 . A roll product according to  claim 1 , wherein the hollow cylindrical core is made from cardboard or paperboard.  
     
     
         6 . A roll product according to  claim 1 , wherein the hollow cylindrical core is made from a synthetic material.  
     
     
         7 . A roll product according to  claim 6 , wherein the synthetic material comprises a thermoplastic component.  
     
     
         8 . A method for the manufacture of a roll product which comprises: 
 sliding a hollow cylindrical core onto a perforated mandrel penetrating means for penetrating the hollow cylindrical core in a direction from the inner surface of the hollow cylindrical core; the mandrel further comprising an inner expanding core which is made to expand and at which the penetrating means are pressed against the inner surface of the hollow cylindrical core; whereby protuberances are formed protruding outwardly from the outer surface of the hollow cylindrical core, principally in the radial direction of the hollow cylindrical core;    advancing a band-shaped web of material having a first end and a second end into contact with the hollow cylindrical core;    bringing the first end into mechanical and releasable engagement with protuberances protruding outwardly from an outer surface of the hollow cylindrical core,    winding the band-shaped web of material onto the hollow cylindrical core.    
     
     
         9 . A method according to  claim 8 , wherein the penetrating means are heated.  
     
     
         10 . A method according to  claim 8 , wherein the penetrating means are retracted before the first end of the band-shaped web of material is mechanically and releasably engaged by the protuberances.  
     
     
         11 . A method according to  claim 8 , wherein the penetrating means are protruding outwardly from the outer surface of the hollow cylindrical core at least during the initial winding step.  
     
     
         12 . A method according to  claim 8 , wherein suction is applied over the hollow cylindrical core through the perforations in the outer cylinder.  
     
     
         13 . An apparatus for the manufacture of a hollow cylindrical core for mechanically and releasably engaging and holding a first end of a band-shaped web of material in an initial winding of the band-shaped web of material, the apparatus comprising a mandrel having an outer perforated cylinder, an inner hollow cylinder with penetrating means arranged on the outer surface of the inner hollow cylinder and an expanding core having a first non-expanded state and a second expanded state, said penetrating means protruding out through the perforations in the outer perforated cylinder when the expanding core is in the expanded state.  
     
     
         14 . An apparatus according to  claim 13 , wherein the penetrating means have a substantially square shape.  
     
     
         15 . An apparatus according to  claim 13 , wherein the penetrating means have a shape which tapers to a point.  
     
     
         16 . An apparatus according to  claim 13 , wherein the penetrating means are made of metal.  
     
     
         17 . An apparatus according to  claim 13 , wherein the penetrating means are arranged uniformly on the inner hollow cylinder.  
     
     
         18 . An apparatus according to  claim 13 , wherein the penetrating means are arranged irregularly on the inner hollow cylinder.  
     
     
         19 . An apparatus according to  claim 13 , further comprising means for advancing the band-shaped web of material into contact with the hollow cylindrical core.  
     
     
         20 . An apparatus according to  claim 13 , further comprising means for applying suction over the hollow cylindrical core.  
     
     
         21 . An apparatus according to  claim 13 , further comprising means for expanding the expanding core.  
     
     
         22 . An apparatus according to  claim 13 , further comprising means for heating the penetrating means  214 .