Brakes – Plastic deformation or breakage of retarder element – Crushable element
Reexamination Certificate
1999-05-07
2001-10-30
Schwartz, Chris (Department: 3613)
Brakes
Plastic deformation or breakage of retarder element
Crushable element
Reexamination Certificate
active
06308809
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a traffic crash attenuation system. More particularly, the present invention includes a system, method and apparatus for absorbing the kinetic energy from an impacting vehicle in a controlled and safe manner with roadside safety devices such as: guardrails and median barrier end treatments, crash cushions, and truck mounted attenuators. Specifically, the present invention provides a system for the controlled rupturing of a tubular member by a mandrel whereby forces of an impacting vehicle are absorbed.
U.S. Pat. No. 4,200,310 illustrates an energy absorbing system which utilizes a number of cylindrical energy absorbing members placed in a series-type relationship on a frame mounted to a truck. The system is provided with an alignment or guidance frame. However, there is nothing which teaches any selectively controlling the rupture of the cylindrical members. The mechanism of energy dissipation is significantly different than that of the present invention.
U.S. Pat. No. 3,143,321, teaches the use of a frangible tube for energy dissipation. As with the present invention, the apparatus disclosed in U.S. Pat. No. 3,143,321 uses a mandrel receivable within a tubular member. However, there is no teaching of a means for selectively controlling the rupturing along a length of the tubular member.
SUMMARY OF THE INVENTION
The crash attenuation system of the present invention provides an impact head attached to an energy absorption mechanism. The energy absorption mechanism has one or more mandrels with a certain tensile strength or hardness attached to the impact head. Attached to the head are one or more tubular members which have second tensile strengths or hardnesses, generally lower than those of the mandrels. The mandrels are receivable in a first end of the tubular members such that upon impact forces being applied to the impact head, the mandrels are forced through the tubular members rupturing, rather than fragmenting, the tubular members and absorbing the impact forces. The rupturing may be controlled by any number or combination of stress concentrating elements such as placing holes, notches, acts, scores, preferential material orientation, or slots in the tubular members, providing gussets (or any strengthening member) along the length of the tubular members, or providing the mandrels with stress concentrators such as gussets or mandrel geometry so that as the mandrels are urged through the tube the rupturing is controlled.
REFERENCES:
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Reid John D.
Rohde John R.
Sicking Dean L.
Jackson Walker L.L.P.
Safety By Design Company
Schwartz Chris
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