Core assembly for winding sheet and winding method

Abstract

A core assembly for a continuous sheet includes a core of a cylindrical form. A side channel is formed in the core to extend fully in an axial direction thereof. A shaft hub is disposed through the core movably in the axial direction. A changing unit or adjuster displaces the core in response to moving of the shaft hub between first and second positions, and enlarges an outer diameter of the core when the shaft hub is in the second position than when the shaft hub is in the first position. Preferably, the changing unit includes a cam roller, disposed on the shaft hub, for projecting in a radial direction. A cam ramp surface is formed with an inner surface of the core, has a height increasing toward the second position, is pressed by the cam roller.

1 . A core assembly for winding a continuous sheet to form a sheet roll, comprising:
 a core of a sleeve shape for winding said sheet thereabout;   a side channel, formed in said core fully in an axial direction, for enabling an outer diameter of said core to change;   a changing unit, disposed through said core movably in said axial direction, shifted to a first position before forming said sheet roll, and shifted to a second position before removing said core from said sheet roll, for pressing an inner surface of said core radially to enlarge said outer diameter when in said first position, and for releasing said inner surface from pressure to reduce said outer diameter when in said second position.   
     
     
         2 . A core assembly as defined in  claim 1 , wherein said changing unit includes plural cam rollers rotatable in contact with said inner surface;
 further comprising plural cam ramp surfaces, formed with said inner surface, pressed by said cam rollers in association therewith when said changing unit is in said first position.   
     
     
         3 . A core assembly as defined in  claim 2 , wherein said changing unit includes:
 a shaft hub; and   plural roller holders, arranged on said shaft hub, secured to first and second axial positions thereon, for projecting radially in each of said first and second axial positions, and for supporting said cam rollers rotatably at holder ends thereof.   
     
     
         4 . A core assembly as defined in  claim 3 , further comprising plural receiving grooves, formed in said inner surface to extend in said axial direction, for receiving and guiding respectively said cam rollers. 
     
     
         5 . A core assembly as defined in  claim 3 , further comprising a regulating device for retaining said changing unit in said first position. 
     
     
         6 . A core assembly as defined in  claim 5 , wherein said regulating device further retains said changing unit in said second position. 
     
     
         7 . A core assembly as defined in  claim 6 , wherein said regulating device includes:
 a first retaining hole formed in said inner surface;   a retaining portion, secured to said changing unit, for entry in said first retaining hole to retain said changing unit in said first position.   
     
     
         8 . A core assembly as defined in  claim 7 , wherein said regulating device further includes a second retaining hole, formed in said inner surface, for positioning said changing unit in said second position upon entry of said retaining portion. 
     
     
         9 . A core assembly as defined in  claim 7 , further comprising a regulating groove, formed in said inner surface, for receiving said retaining portion, said first retaining hole being formed with said regulating groove. 
     
     
         10 . A core assembly as defined in  claim 9 , wherein said retaining portion is constituted by a ball plunger for retention in a releasable manner. 
     
     
         11 . A core assembly as defined in  claim 9 , further comprising a moving device for moving said retaining portion between a retained position of entry in said first retaining hole and a released position of release from said first retaining hole. 
     
     
         12 . A core assembly as defined in  claim 11 , wherein said retaining portion includes a regulating rod biased toward said retained position;
 said moving device includes:   a projection, disposed at an end of said shaft hub, pulled for moving said changing unit from said second position to said first position, and pushed for moving said changing unit from said first position to said second position; and   a rod, disposed through said shaft hub in a slidable manner, having one end provided with said projection, for moving said regulating rod toward said released position when said projection is pushed.   
     
     
         13 . A core assembly as defined in  claim 12 , wherein said moving mechanism further includes a link arm for connecting said rod and said regulating rod. 
     
     
         14 . A winding method of winding a continuous sheet about a core assembly including a core of a sleeve shape, a side channel formed in said core fully in an axial direction, and a changing unit disposed through said core movably in said axial direction, said winding method comprising steps of:
 shifting said changing unit to a first position by moving through said core, for said changing unit in said first position to press an inner surface of said core radially to enlarge an outer diameter thereof;   rotating said core assembly to wind said sheet thereabout;   after winding said sheet, shifting said changing unit to a second position to release said inner surface from pressure to reduce said outer diameter;   removing said core assembly from a sheet roll of said sheet.   
     
     
         15 . A winding method as defined in  claim 14 , wherein said core assembly is supported by a pair of surface rollers disposed in parallel with one another, and is rotated by rotation of said surface rollers in a common direction.