| 摘要 |
A laminar backing wheel for the abrasive belt of a belt grinder or polisher has a disk of soft and resilient material compressed to one half or less of its relaxed axial thickness between two disks of stronger and more rigid material by threads stitched axially through the wheel. When the wheel stands still, or moves slowly, the tensioned belt rides over the circumferences of the more rigid material. At normal operating speed, the soft material of the first disk is caused to project beyond the more rigid disks by centrifugal forces and spreads axially into radial alignment with the more rigid disks to provide a soft backing for the belt while deformation of the wheel under starting stresses is resisted by the harder disks. |
