Flat articles are inserted into printed products (3) continuously conveyed by grippers (11) of a gripper conveyor (1), wherein the printed products are held by the grippers at their fold or spine edges and wherein the grippers (11) are conveyed through a deflection region from below round an essentially horizontal deflection axis (2). Pegging elements (4) rotating around the deflection axis (2) are arranged along both sides of the deflection region and synchronized with the grippers, and form axially aligned and inter-spaced pairs and are radially distanced from the grippers. The printed products (3) are conveyed in a hanging manner into the deflection region and they are opened immediately upstream of the deflection region. The pegging elements (4) are activated as the grippers (11) enter the deflection region to grab the trailing part (32) of one opened printed product (3) and the leading part (31) of the next product by the corners opposite the fold or spine edge by clamping them together until the grippers (11) exit the deflection region.