Patent ID: 6641513
Filing Date: 2003-11-04
Classification: B65H

Abstract:
An improved, low inertia, relatively frictionless roller for handling high speed, fragile webs, the improved roller comprising:a source of compressible fluid that has a preselected pressure; an inner tube that has a radially outwardly facing surface; that has a first end and a second end; and that has a longitudinal central axis extending between the first and second ends; an outer, web contacting tube that has a first end and a second end; that has a longitudinal central axis extending between the first and second ends of the outer tube; that is disposed about the inner tube so that the longitudinal central axes of the inner and outer tubes are coaxial and so that the outer tube may rotate about the coaxial central axes with respect to the inner tube; that has a radially outwardly facing surface partially circumferentially extending, that has a radially inwardly facing surface; the inwardly facing surface of the outer tube and the outwardly facing surface of the inner tube defining therebetween an annular gap that has a preselect radial thickness, that has a first, partially circumferentially extending portion adjacent to the partially circumferentially extending portion of the outer tube which is in contact with a web as the web passes about the roller and that has a second, partially circumferentially extending portion spaced circumferentially from the first portion; a first compressible fluid passage that is in the inner tube and that is in fluid communication with the compressible fluid source; a second compressible fluid passage that is in the inner tube, that exhausts compressible fluid from the inner tube, and that is in fluid communication with the second portion of the annular gap; and a fluid flow restriction device that is in the inner tube that includes a fluid flow path which permits the flow of compressible fluid, in a preselectedly restricted manner, from the first passage to the first portion of the annular gap, with the radial dimension of the annular gap being selected so that there is a reduction in the pressure of the compressible fluid as the compressible fluid passes from the first portion of the annular gap to the second portion of the annular gap and so that the force of the web passing around the web portion of the outer tube is substantially balanced by the pressure of the compressible fluid in the first portion of the annular gap.