US Patent 7543866 Bumper structure

A bumper structure for the front and rear area of a motor vehicle includes a bumper cross member, and a crash box placed between the cross member and an end of a side rail. At least two bolted connections, extending in upright direction of the motor vehicle and disposed in parallel relationship, are provided for detachably securing the cross member to the crash box, wherein one of the bolted connections extends through a bore to define a pivot axis of the cross member whereas the other one of the bolted connections is arranged in an oblong hole to allow a limited rotation of the cross member about the pivot axis. In this way, damage to the crash box that is distal to the impact site is prevented.