Patent ID: 7604268

Claim:
A trailer crash attenuation system comprising: a crash cushion; a casing adapted to receive at its distal end said crash cushion; an energy absorption mechanism for absorbing crash energy when said crash cushion is subjected to an impact, said energy absorption mechanism comprising: a first longitudinal hollow member, wherein a portion at one end is adapted to act as a first hydraulic cylinder and has a relatively small orifice; hydraulic fluid disposed in said first hydraulic cylinder; a hydraulic tank in fluid connection with said first hydraulic cylinder through said relatively small orifice; and a first telescopic longitudinal member adapted to slide in and out of said first longitudinal hollow member, said first telescopic longitudinal member sliding into said first longitudinal hollow member when said crash cushion is subjected to an impact, said first telescopic longitudinal member forcing said hydraulic fluid out of said first hydraulic cylinder whereby the impact energy is at least partially absorbed by said hydraulic fluid; and an off-set impact countering mechanism for preventing jack-knifing of said trailer crash attenuation system when an impact occurs at an offset from the longitudinal axis of said trailer crash attenuation system, said off-set impact countering mechanism comprising: second and third longitudinal hollow members disposed substantially parallel to and on either side of said first longitudinal hollow member; and second and third longitudinal telescopic members adapted to slide in and out of said second and third longitudinal hollow members respectively.