Patent ID: 7967118

Claim:
An impact absorber device, comprising at least one first portion having a short tubular shape, and at least one second portion having a short tubular shape concentrically disposed in a stacked relationship with said first portion, wherein said first portion and said second portion engage with each other at an engagement portion which is inclined with respect to a concentric axis of said first portion and said second portion, wherein a stress to be applied to the impact absorber device in a direction of the concentric axis is divided into a force in a radius direction by the engagement portion of the first portion and the second portion, such that the first portion shrinks in a radially inward direction and the second portion expands in a radially outward direction, and wherein the engagement portion of the first portion and the second portion includes an inclined face of the first portion and an inclined face of the second portion which are abutted to each other, and at least one of the first portion and the second portion further comprises an additional inclined portion with an inclination angle different from the inclination angle of the inclined face at least one of a radially innermost portion and a radially outermost portion of the inclined face.