Patent ID: 7445097

Claim:
A crash energy absorption member comprising a tubular body which has a length L and a polygonal transverse cross-sectional shape, the tubular body formed by a plurality of sidewalls having opposing ends, each sidewall having an exposed outer surface which connects with adjacent sidewall outer surfaces to form a continuous crash energy absorption member outer peripheral surface, the sidewalls and opposing ends forming a unitary tubular body with inside surfaces of the joined sidewalls forming an unrestricted interior space within the tubular body, the tubular body including 2 n corners (wherein n is a natural number greater than or equal to 3) due to having 2 n ridge lines and 2 n surfaces partitioned by these 2 n ridge lines and which absorbs impact energy by buckling when an impact load is applied to one end of the member in the axial direction towards the other end thereof, characterized in that some of the 2 n ridge lines exist only in a region which extends from a position spaced by a distance h in the axial direction from the one end to the other end, the absorption member having a number of ridge lines m having a length L, and the following equations are satisfied: h≦L ×0.30 (1) 4≦ m ≦2×( n −1) (2).