Patent ID: 6446554
Filing Date: 2002-09-10
Classification: B41F

Abstract:
A sheet-fed printing press capable of printing on both sides of a sheet comprising:a turn-over drum provided with turn-over grippers for gripping the sheet; control cams respectively disposed on the axially opposite sides of said turn-over drum in such a manner as to be displaceable in the axial direction of the turn-over drum, said control cams each having an outer circumferential surface forming thereon a cam surface for the single-side printing operation and a cam surface for the both-side printing operation, both the cam surfaces on each of said control cams being arranged adjacent to each other in the axial direction of the turn-over drum; cam followers for driving said turn-over grippers respectively disposed on the axially opposite ends of the turn-over drum, said cam followers each being designed to travel around the outer circumference of a corresponding one of said control cams as sliding along one of said cam surfaces through the rotation of the turn-over drum, thereby controlling the motions of the turn-over grippers, wherein said control cams are displaced in the axial direction of the turn-over drum, thereby enabling said cam followers to switch the cam surface to be engaged for switching to the single-side printing operation or to the both-side printing operation; stationary guide means for guiding said control cams in the axial direction of the turn-over drum; switching cam followers respectively provided on the control cams in such a manner as to protrude radially outwardly therefrom; sliders respectively forming therein camming recesses to be respectively engaged with said switching cam followers; a slider driving means for reciprocatingly driving the sliders in such a manner as to enable the switching cam followers to reciprocatingly travel in the axial direction of the turn-over drum, wherein said switching cam followers each travel from a first end to a second end of a corresponding one of said camming recesses along the longitudinal axis thereof for switching to the both-side printing operation, and each travel from said second end to said first end of said corresponding one of said camming recesses along the longitudinal axis thereof for switching to the single-side printing operation, and said first and second ends along the longitudinal axis of each camming recess respectively have end walls adapted to press a corresponding one of said switching cam followers, so that the control cams are respectively biased against the stationary guide means in the direction substantially orthogonal to the axial direction of the turn-over drum at the time of completion of the switching operation.