Patent ID: 6341698
Filing Date: 2002-01-29
Classification: B65H

Abstract:
A sheet stacking device, comprised of:a sheet support bed comprised of a plurality of side-by-side rollers, each of said rollers being freely rotatable about a respective roller axis; a support bed drive assembly for moving said sheet support bed in a predetermined direction along a closed path, said path having an upper horizontal run and a lower horizontal run and being dimensioned such that a gap exists between a leading end and a trailing end of said sheet support bed, said gap moving along said path as said sheet support bed moves along said path; a roller control assembly for selectively controlling rotation of each of said rollers about its respective roller axis; and a controller for selectively and sequentially controlling the operation of said support bed drive assembly and said roller drive assembly, wherein said stacking device is operable to perform the following operational steps: a) causing said support bed drive assembly to move said sheet support bed to a sheet receiving position on said upper run of said path; b) causing said roller control assembly to allow said rollers to rotate freely to receive a sheet to be stacked on said support bed; c) causing said support bed drive assembly to move said sheet support bed at a predetermined speed along said path to move said sheet to a â€œstacking positionâ€ ; d) when said sheet is at said stacking position, causing said roller control assembly to rotate said roller in a predetermined direction at a predetermined speed while said support bed continues to move along said path, wherein said rollers are operable to convey said sheet in a direction opposite the direction of said support bed at a speed wherein said sheet remains essentially stationary at said â€œstacking positionâ€ ; e) continuously driving said sheet support bed along said path and continuously rotating said roller wherein said sheet becomes unsupported as said trailing end of said sheet support bed passes under said sheet and said sheet drops through said gap onto said sheet support bed as it moves along said lower run; f) causing said rollers along said lower run to rotate at a predetermined speed in a predetermined direction wherein said sheet is conveyed in a direction opposite said direction of said support bed at a speed wherein said sheet remains essentially stationary at a position essentially below said stacking position; and g) continuously driving said sheet support bed along said path and continuously rotating said roller along said lower run wherein said sheet becomes unsupported as said trailing end of said sheet support bed passes under said sheet and said sheet drops through said gap onto a stacking platform.