a restraining apparatus for securing a position of a side impact beam having u - shaped or trapezoidal cross section and formed with at least partially flattened ends , for execution of a subsequent , includes two support blocks for supporting the ends . associated to the support blocks are two vertical clamping units , wherein the support blocks and the clamping units are placed into one - to - one correspondence . the restraining apparatus further includes a stop member for abutment by one of the ends , and two transverse clamping units intended for clamping length sections of the side impact beam between the beam ends .