Impact attenuator

Abstract

A crash cushion includes first and second diaphragm frames each having first and second laterally spaced sides defining first and second planes sloping inwardly from a top to a bottom of each side of the first and second diaphragm frames. The first diaphragm frame is moveable relative to the second diaphragm frame in response to a head-on impact. The first and second side panels are attached respectively to the first and second sides of the first and second diaphragm frames, wherein the first and second side panels are moveable relative to the second diaphragm frame in response to the head-on impact. In one embodiment, the side panels may have variable cross sectional shapes along a length thereof. In addition, each frame may include a plurality of longitudinally spaced guides for engaging a rail.

1 . A crash cushion comprising:
 first and second diaphragm frames each comprising first and second laterally spaced sides defining first and second planes sloping inwardly from a top to a bottom of each side of the first and second diaphragm frames, wherein the first diaphragm frame is moveable relative to the second diaphragm frame in response to a head-on impact: and   first and second side panels attached respectively to the first and second sides of the first and second diaphragm frames, wherein the first and second side panels are moveable relative to the second diaphragm frame in response to the head-on impact.   
     
     
         2 . The crash cushion of  claim 1  further comprising first and second laterally spaced rails, wherein at least the first diaphragm comprises first and second sets of a plurality of spaced apart guides slidably engaging the first and second rails respectively. 
     
     
         3 . The crash cushion of  claim 2  further comprising a spacer disposed between adjacent pairs of the spaced apart guides in each of the first and second sets. 
     
     
         4 . The crash cushion of  claim 3  where each set comprises three guides, and further comprising two of the spacers disposed between the adjacent pairs of guides in each set. 
     
     
         5 . The crash cushion of  claim 1  wherein each of the first and second side panels comprises a first cross sectional shape at an upstream end of the side panel, a second cross sectional shape at a midpoint of the side panel and a third cross sectional shape at the downstream end of the side panel, wherein the first, second and third cross sectional shapes are different. 
     
     
         6 . The crash cushion of  claim 5  wherein the first, second and third cross-sectional shapes have first, second and third heights respectively, wherein the third height is greater than the second height. 
     
     
         7 . The crash cushion of  claim 6  wherein the second height is greater than the first height. 
     
     
         8 . The crash cushion of  claim 7  wherein the width of each of the first and second side panels is the same at the upstream end, the midpoint and the downstream end. 
     
     
         9 . The crash cushion of  claim 6  wherein the upper and lower surfaces of each of the first and second side panels are linear. 
     
     
         10 . The crash cushion of  claim 6  wherein each of the first and second side panels comprises a W-beam. 
     
     
         11 . The crash cushion of  claim 1  comprising a third diaphragm frame positioned downstream of the second diaphragm frame, wherein the third diaphragm frame comprises first and second laterally spaced sides defining first and second planes sloping inwardly from a top to a bottom of each side of the third diaphragm frame, wherein the second diaphragm frame is moveable relative to the third diaphragm frame in response to a head-on impact: and
 third and fourth second side panels attached respectively to the first and second sides of the second and third diaphragm frames, wherein the third and fourth side panels are moveable relative to the third diaphragm frame in response to the head-on impact. 
 
     
     
         12 . An impact attenuator comprising:
 first, second and third longitudinally spaced frames; and   a first side panel attached to the first and second frames, and a second side panel attached to the second and third frames, wherein the first and second side panels are moveable relative to the second and third frames respectively in response to a head-on impact, wherein each of the first and second side panels comprises a first cross sectional shape at an upstream end of the side panel, a second cross sectional shape at a midpoint of the side panel and a third cross sectional shape at the downstream end of the side panel, wherein the first, second and third cross sectional shapes are different.   
     
     
         13 . The impact attenuator of  claim 12  further comprising a rail, wherein at least the first frame comprises a plurality of spaced apart guides slidably engaging the rail. 
     
     
         14 . The impact attenuator of  claim 13  further comprising a spacer disposed between adjacent pairs of the spaced apart guides. 
     
     
         15 . The impact attenuator of  claim 14  where the plurality of spaced apart guides comprises three guides, and further comprising spacers disposed between the adjacent pairs of guides. 
     
     
         16 . The impact attenuator of  claim 12  wherein the upstream end has a first height, the midpoint has a second height, and the downstream end has a third height, wherein the third height is greater than the second height. 
     
     
         17 . The impact attenuator of  claim 16  wherein the second height is greater than the first height. 
     
     
         18 . The impact attenuator of  claim 17  wherein the width of each of the first and second side panels is the same at the upstream end, the midpoint and the downstream end. 
     
     
         19 . The impact attenuator of  claim 16  wherein the upper and lower surfaces of each of the first and second side panels are linear. 
     
     
         20 . The impact attenuator of  claim 12  wherein the side panel comprises a W-beam. 
     
     
         21 - 27 . (canceled) 
     
     
         28 . An impact attenuator comprising:
 first, second and third longitudinally spaced frames; and   a first side panel attached to the first and second frames, and a second side panel attached to the second and third frames, wherein the first side panel is moveable relative to the second side panel from a pre-impact position to an impact position in response to a head-on impact, wherein the first panel comprises a downstream end overlapping an upstream end of the second panel in a non-interference configuration in the pre-impact position, and wherein the first panel comprises a downstream end overlapping the downstream end of the second panel in an interfering configuration in the impact position.