Patent ID: 7540702

Claim:
A device for stacking flat products and folding boxes in a stack shaft, the device comprising: an upper transport unit; a lower transport unit; an upper conveyor belt disposed on said upper transport unit, said upper conveyor belt having a front end facing the stack shaft; a lower conveyor belt disposed on said lower transport unit, said lower conveyor belt having a front end facing the stack shaft, wherein the flat products are transported towards the stack shaft between said upper and said lower conveyor belts; first means for extending said front end of said upper conveyor belt while retracting said front end of said lower conveyor belt, wherein vertical positions of said upper and said lower conveyor belts thereby remain substantially unchanged in association with extension and retraction thereof, said first means structured and dimensioned to permit downward stacking of the flat products below said extended front end of said upper conveyor belt and past said retracted front end of said lower conveyor belt; second means for retracting said front end of said upper conveyor belt while extending said front end of said lower conveyor belt, wherein vertical positions of said upper and said lower conveyor belts thereby remain substantially unchanged in association with extension and retraction thereof, said second means structured and dimensioned to permit upward stacking of the flat products above said extended front end of said lower conveyor belt and past said retracted front end of said upper conveyor belt; and a stack support comprising either a horizontal support for supporting the stack during downward stacking and a portion of the lower conveyor belt for supporting the stack during upward stacking.