Impact absorbing bumper system

Claim 1

An impact absorbing bumper system for a wheeled vehicle which has an end cross member, and at least one side frame extending from the end cross member inwards and substantially longitudinally of the vehicle comprising: a bumper outside the end cross member; a retractable strut integrated with said bumper and extending from said bumper through the end cross member inwards and substantially longitudinally of the vehicle; and mounting means, which comprises a torsion bar embedded in the side frame, for mounting said retractable strut on said side frame, resisting an impact force transmitted from said retractable strut upon a collision of the vehicle with a solid barrier at lowintermediate speed and converting a portion of an impact transmitted from said retractable strut to a torsion energy of said torsion bar upon a collision of the vehicle with a solid barrier at high speed, said mounting means further comprising two arms integrated wih said torsion bar and extending from upper and lower ends of said torsion bar to said retractable strut for holding said retractable strut therebetween; and fastening means for fastening said two arms to said retractable strut, said mounting means further comprising a block built in said side frame, in which block said torsion bar is embedded, and said torsion bar still further comprising a central portion having a square cross-section; an upper end having a square cross section; a rod portion interconnecting said central portion and said upper end; a lower end having a square crosssection; and a second rod portion interconnecting said central portion and said lower end, and wherein said torsion bar is embedded at the central portion thereof in said block built in said side frame.