Automatic retard adjustment mechanism for sheet feeding

Abstract

A sheet feeding apparatus includes a retard mechanism to prevent the inadvertent feeding of doubled or overlapped sheets. The retard mechanism includes a plurality of belts in an assembly positioned adjacent to a sheet feeding roller, and rotating in such a direction as to retard the sheets being fed. The retard assembly is mounted on the free end of a lever arm pivotally secured adjacent to its other end to the base of the sheet feeding apparatus. The lever arm with the retard assembly mounted thereon is spring-urged toward the feed roller, but may be moved slightly away from said roller to accommodate the thickness of the sheet being fed between the feed roller and the retard assembly. A dual spring arrangement contained in the lever arm permits the lever arm to move with relatively little force to accommodate passage of a single sheet, but to resist more vigorously any additional movement, such as would be required for the passage of double or overlapped sheets. A one-way retaining device permits movement of the lever arm and retard assembly toward the feed rollers as the roller and belts wear, but prevents movement away from said roller except for the limited movement permitted to accommodate sheets during feeding. The retaining device may be released to permit the lever arm and retard assembly to be swung away from the feed roller for replacement of the feed roller and retard belts when worn.