Abstract: A loading station located at one side of a feeding conveyor, into which the corners of a sheet can be loaded. The station comprises two movable clamping devices supported on a track which runs across the rear of the feeding conveyor. Each clamping device is driven by an independent transmission system, the two transmission systems are connected to a selfcentering interlock mechanism. The centering mechanism is arranged to permit independent movement of the two clamping mechanisms, whereby they can move from the side position into a position in front of the feeding conveyor. The centering mechanism will then automatically control the tensioning and positioning of the leading edge of the sheet which is held by the clamping devices irrespective of the width of the sheet.This will result in the center of the sheet being positioned in line with the required feeding center of the feed conveyor.