Patent ID: 7651155

Claim:
An energy absorber comprising: a first shell and a second shell, each shell having longitudinal extending edge portions engaging with corresponding edge portions of the other shell and attached thereto so that the shells cooperate to form a tubular structure having opposed walls defined by the shells, said tubular structure having longitudinally spaced ends adapted to receive force applied in the longitudinal direction; a plurality of webs located within the tubular structure, said webs being channel shaped with a wall extending in the longitudinal direction and longitudinal extending edge flange portions attached to opposing walls of the tubular structure; whereby a longitudinal force applied to the tubular structure causes longitudinal collapse of the tubular structure and the longitudinal collapse of the webs including both the walls and the edge flange portions to absorb the longitudinal applied force; said plurality of webs being of varying length from one another and each of the plurality of webs being spaced from the longitudinal end of the tubular structure so that upon progressive collapse of the energy absorber the first and second shells collapse initially and then the plurality of webs are serially engaged and deformed to contribute serially to the energy absorption.