Highway crash cushion

Abstract

A highway crash cushion provides a novel system response profile that reduces the stopping distance of an impact event. This crash cushion includes a frame that forms at least two bays arranged one behind another in an anticipated impact direction. The frame includes at least three transverse frames and side frames extending between adjacent transverse frames. Each of the side frames is outwardly bowed and includes first and second side frame elements coupled to the respective transverse frames, and a hinge coupled between the first and second side frame elements. At least one energy absorbing element is disposed in one of the bays, and at least first and second restraints are coupled to the side frames to resist movement of the hinges at an early stage in an impact event. The crash cushion is partially collapsed automatically as the crash cushion is raised from a horizontal to a vertical position, and then extended automatically to its operational position as the crash cushion is lowered from the vertical to the horizontal position. The energy absorbing elements can include tapered frusto-conical sheet metal elements that are stacked with the smaller ends facing first and second opposed sides of the energy absorbing element.

1 . A highway crash cushion comprising: 
 a frame forming at least first and second bays arranged one behind another in an anticipated impact direction, said frame comprising: 
 at least first, second and third transverse frames spaced from one another along the anticipated impact direction such that the first bay is between the first and second transverse frames and the second bay is between the second and third transverse frames;  
 at least first, second, third and fourth side elements, said first and second side elements extending between the first and second transverse frames on respective sides of the first bay, and said third and fourth side elements extending between the second-and third transverse frames on respective sides of the second bay;  
 at least one energy absorbing element disposed in at least one of the bays;  
 in an initial condition each of said side elements bowing outwardly from the respective bay;  
 in a collapsed condition after an impact of sufficient seventy, at least some of the side elements bowing outwardly to a greater extent than in the initial condition to accommodate movement of the respective transverse frames toward one another.  
   
     
     
         2 . The invention of  claim 1  wherein the first-mentioned energy absorbing element is disposed in the first bay, and further comprising a second energy absorbing element disposed in the second bay, wherein the first and second energy absorbing elements are shorter than the respective bays by respective first and second distances in the anticipated impact direction, and wherein the first and second distances differ from one another.  
     
     
         3 . The invention of  claim 1  wherein the first-mentioned energy absorbing element is disposed in the first bay, and further comprising a second energy absorbing element disposed in the second bay, wherein the first and second energy absorbing elements differ in stiffness in the anticipated impact direction.  
     
     
         4 . The invention of  claim 1  wherein the side elements and the transverse frames are joined together to form a unit adapted to be cantilevered from a vehicle.  
     
     
         5 . A highway crash cushion comprising: 
 a frame forming at least first and second bays arranged one behind another in an anticipated impact direction, said frame comprising: 
 at least first, second and third transverse elements spaced from one another along the anticipated impact direction such that the first bay is between the first and second transverse elements and the second bay is between the second and third transverse elements;  
 at least first, second, third and fourth side elements, said first and second side elements extending between the first and second transverse elements on respective sides of the first bay, and said third and fourth side elements extending between the second and third transverse elements on respective sides of the second bay;  
 at least one energy absorbing element disposed in at least one of the bays; and  
 in an initial condition at least some of the side elements bowing away from a respective line extending between end portions of the respective side element.  
   
     
     
         6 . A highway crash cushion comprising: 
 a frame forming at least first and second bays arranged one behind another in an anticipated impact direction, each of said bays comprising a front and a back, said frame comprising: 
 at least first, second, third and fourth side elements, each of said side elements extending between the front and the back of a respective bay, said first and second side elements disposed on respective sides of the first bay, and said third and fourth side elements disposed on respective sides of the second bay;  
 at least one energy absorbing element disposed in at least one of the bays; and  
 in an initial condition at least some of the side elements bowing away from a respective line extending between end portions of the respective side element.  
   
     
     
         7 . The invention of  claim 5  or  6  wherein said at least some of the side elements bow away from the respective lines to a greater extent after an impact of sufficient severity than in the initial condition, thereby accommodating compression of the at least one energy absorbing element.  
     
     
         8 . The invention of  claim 5  wherein the side elements and the transverse elements are joined together to form a unit adapted to be cantilevered from a vehicle.  
     
     
         9 . The invention of  claim 5  or  6  wherein each of the side elements bows outwardly from the respective bay in the initial condition.  
     
     
         10 . The invention of  claim 5  or  6  wherein the first-mentioned energy absorbing element is disposed in the first bay, and further comprising a second energy absorbing element disposed in the second bay, wherein the first and second energy absorbing elements are shorter than the respective bays by respective first and second distances in the anticipated impact direction, and wherein the first and second distances differ from one another.  
     
     
         11 . The invention of  claim 5  or  6  wherein the first-mentioned energy absorbing element is disposed in the first bay, and further comprising a second energy absorbing element disposed in the second bay, wherein the first and second energy absorbing elements differ in stiffness in the anticipated impact direction.