A swing-up loader for a signature machine serves as an extension for the pile feed mechanism. The loader has its own conveyor belts and drive. When placed in its operating position, the loader adjoins the regular infeed of the signature feeder at a junction. A microswitch senses the height of the signature pile at the junction. When the pile height falls due to removal of signatures at the stockplate, the microswitch calls for movement of the loader's drive belts. This movement transfers signatures on the loader across the junction to the regular infeed of the signature feeder. The loader maintains a full infeed to assure a uniform pressure at the stockplate.