Tubular core and method

Abstract

Disclosed is a tubular core on which sheets of metal or other material can be wound and supported, for shipment, handling and dispersal, and a method for forming the core. The core comprises a metal sheet or strip which has a rectangular-ribbed cross-sectional profile comprising rectangular, flat ribs, and which is wound spirally into a tubular configuration. The core is formed by passing the strip through a plurality of roll-forming stands, to progressively form sections of the ribs and progressively define the sections into the rectangular ribbed profile in which the flat ribs collectively form a support surface for the sheets which are to be wound on the core.

1 . A method for forming a metal strip into a cylindrical core, comprising:
 passing an elongated metal strip having width and length and opposite longitudinal edges through a multiplicity of forming stands which form rectangular components and generally straight segments thereof in said strip and change the size and shape of the segments and components previously formed at said forming stands, wherein upon the completion of the corrugation forming process the strip comprises longitudinally extending, alternating ridges and grooves having generally vertical spaced-apart sidewalls with the ridges further comprising longitudinally extending, flat, spaced-apart top surfaces extending between adjacent ridge sidewalls and the grooves further comprising longitudinally extending, flat, spaced-apart bottom surfaces extending between adjacent groove sidewalls, the flat ridges and flat grooves together forming a rectangular, flat ribbed cross sectional profile extending along the width of the strip transverse to the length thereof;   forming the opposite longitudinal edges of the as-formed corrugated metal strip into flanges adapted for forming an interlocking seam;   helically coiling the as-formed corrugated strip into a cylinder having a longitudinal axis and an outer surface defined by flat, spaced-apart surfaces selected from the top surfaces and the bottom surfaces; and   compressing the opposite edge flanges together thereby forming an interlocking seam extending in a spiral around the cylinder along the longitudinal axis thereof.   
     
     
         2 . The method of  claim 1  wherein the metal strip is aluminum and is 0.005″ to 0.050″ thick. 
     
     
         3 . The method of  claim 2  wherein during the helical coiling step, the metal strip is oriented at a helix angle of approximately 60° or greater relative to the longitudinal axis. 
     
     
         4 . The method of  claim 2  wherein during the helical coiling step, the metal strip is oriented at a helix angle relative to the longitudinal axis selected for forming a cylinder having a diameter of at least approximately 6″. 
     
     
         5 . A cylindrical core, comprising:
 an elongated metal strip having width and length and being helically coiled into a cylinder, the cross-sectional profile of the strip along the width thereof transverse to the length thereof comprising a rectangular ribbed configuration formed by longitudinally extending, alternating ridges and grooves, the ridges having longitudinally extending, flat, spaced-apart top surfaces, the grooves having longitudinally extending, flat, spaced-apart bottom surfaces, and the flat ridges and the flat grooves together forming a flat ribbed transverse cross section;   said cylinder having an outer surface formed by flat spaced-apart surfaces selected from the top surfaces of the ridges and the bottom surfaces of the grooves; and   a lockseam of joined opposite edges of the metal strip, the lockseam extending in a spiral around the cylinder along the longitudinal axis thereof.   
     
     
         6 . The core of  claim 5  wherein the metal strip is aluminum and is 0.005″ to 0.050″ thick. 
     
     
         7 . The core of  claim 6  wherein the pipe diameter is at least approximately 6″. 
     
     
         8 . The core of  claim 7  wherein prior to forming the cylinder the aluminum strip is approximately 0.023″ thick and approximately 35/8″ wide; the vertical dimension between adjacent top and bottom surfaces of the as-formed cylinder is approximately 0.27″; the width of the flat ridge surfaces is approximately 0.27″; the distance between adjacent flat ridge surfaces is approximately 0.27″; the width of the flat groove surfaces is approximately 0.27″; the distance between adjacent flat groove surfaces is approximately 0.27″; and the diameter of the cylinder is within the range approximately 16″-24″.