Patent ID: 6056471
Filing Date: 2000-05-02
Classification: E01F,Y10T

Abstract:
A multiple necked-down break-away coupling for a highway and roadside appurtenance to be mounted on a base, the coupling defining an axis and comprising a controlled breaking region arranged along said axis and having opposing axial ends; first connecting means for connecting one of said opposing axial ends to the highway or roadside appurtenance; second connecting means for connecting another one of said opposing axial ends to the base on which the highway or roadside appurtenance is to be mounted, said controlled breaking region including at least two axially spaced necked-down portions coaxially arranged between said first and second connecting means, each necked-down portion essentially consisting of two axially aligned conical portions inverted one in relation to the other and generally joined at their apices to form a generally hour-glass shaped configuration having a region of minimal cross-section at an inflection point having a gradually curved annular concave surface defining a radius of curvature, each of said two necked-down portions having different radii of curvature at respective inflection points to provide different failure modes as a function of the position and direction of impact of a force on the appurtenance.