Patent ID: 8104841

Claim:
An attachment assembly for securing a child safety seat to a mounting portion of a vehicle, the attachment assembly comprising: a guide having a channel open to a front face of the guide, the channel including a first side wall and a second side wall opposite to the first side wall, and the first side wall being secured to the vehicle; and a flat metal strap positioned along the first side wall and the second side wall in the channel of the guide in a retracted configuration such that a free end of the metal strap is adjacent to the front face of the guide, a fixed end of the metal strap is secured to a side of the channel, and a body of the metal strap is bent along a radius so as to double back between the free end and the fixed end where the radius is larger than a thickness of the metal strap and is limited by a distance between the first side wall and the second side wall; wherein the metal strap has a first thickness of metal in a first region that decreases to a second thickness of metal in a second region along a length of the strap, the second thickness of metal is continuous across a width of the strap, the second region is positioned away from the radius, and the second region is between the fixed end and the radius when the strap is in the retracted configuration; wherein, when the metal strap is pulled in tension, the metal strap is configured to transition from the retracted configuration to an extended configuration, the radius being freely movable in a direction of the transition, and transitioning of the metal strap is constrained by contact of the metal strap with the first side wall and the second side wall so that the strap rolls along the radius within the guide, thereby absorbing energy, wherein the second region travels through the radius when the strap transitions from the retracted configuration to the extended configuration to thereby vary an amount of energy absorbed by rolling different portions of the metal strap along the radius within the guide.