Method and device for feeding sheets one by one from a pile of sheets

A method for feeding sheets (1) one by one from a stack of sheets in a feeding device to a transportation device (2) for transporting the sheet to a process station, the feeding device comprising a low-pressure chamber (3), a number of separately driven shafts (15) which are positioned perpendicular to the direction of transportation and are arranged in the low-pressure chamber essentially equidistantly spaced from one another and which each carry a plurality of wheels (17) with friction lining, each shaft (15) being driven by its own motor (16), which is connected to and controlled by a control unit (20), and a separating device (19), which is arranged essentially vertically above the low-pressure chamber (3) and at a distance from the low-pressure chamber that is somewhat larger than the thickness of a sheet (1), the lowermost sheet (1(1)) in the stack being fed to the transportation device, while the second lowermost sheet (1(2)) is prevented from being moved by means of the separating device (19), the wheels (17), from being immobile at the beginning of each feeding cycle, being caused to rotate by means of the control unit (20) connected to the drive motors (16) of the wheels (17) and to said process station, in order to accelerate the sheet (1(1)), so that it reaches its speed reference value depending on the working pace of the process station, wherein a relieving element (30) is raised essentially at the same time as the rear edge of the sheet (1(1)) being fed, as seen in the direction of transportation (5), is moved past said element to a supporting position for the second lowermost sheet (1(2)) of the stack of sheets before the sheet (1(1)) being fed leaves a subsequent shaft (15), as seen in the direction of transportation, which carries wheels (17) and that said shaft (15) is decelerated when the rear edge of the sheet (1(1)) being fed, as seen in the direction of transportation, leaves the wheels (17) of the shaft.