US Patent 7137648 Load limiting structure for vehicle occupant restraint system

A load-limiting device has a mechanical structure designed to dissipate forces applied by a vehicle occupant to a safety belt during a crash. The load limiting device comprises a housing and a deformable member, at least one of which is configured for connection to a vehicle safety belt and the other of which is configured for connection to a structural part of a vehicle. The housing and the deformable member are moveable relative to each other when force is applied to the one of those members. The housing supports a hardened member formed of a material which is harder than the deformable member and which is positioned to engage and deform the deformable member as the deformable member is being moved relative to the housing.