Patent Publication Number: US-6902151-B1

Title: Wire rope safety barrier

Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The present invention relates to a wire rope safety barrier. 
   SUMMARY OF THE INVENTION 
   The present invention refers to a wire rope safety barrier of the type used for fencing off the carriage ways running in opposite direction on roads, and also as side fences between a road and the area directly adjacent the road, and consisting of a plurality of posts, which are spaced apart along the extension of carriage way/the road and together support at least two substantially horizontal fence ropes, preferably consisting of steel ropes or wires. Those fences are provided for preventing vehicles from traveling off the carriage way sideways, and particularly for crossing over into the opposed carriage way at accidents with cars caused by car breakdowns, collisions or the like. 
   The purpose of the invention is to offer such a wire rope safety barrier, which in a secure manner will catch a vehicle which is hitting the wire rope safety fence, and thereby absorb at least a major part of the weight and kinematic force from the vehicle, thus that the vehicle will be retained in its own carriage way and not cross over to the carriage way of the oncoming vehicles, or driving off the road. 
   It is furthermore essential that it is prevented as far as possible, that components of such a safety barrier which will come loose at a collision is not thrown over in the carriage way of the oncoming traffic. 
   Another purpose of the invention is to secure as far as possible that as few components as possible are thrown off the safety barrier at such a collision. 
   For achieving this it is suggested that a wire rope safety barrier for positioning along roads and/or between carriage ways for traffic in opposite directions, incorporates a plurality of spaced apart posts, which are substantially vertically anchored in the road side and/or in a strip positioned between the carriage ways for traffic in opposite directions, which posts in a sliding manner supports a number of wire ropes, which wire ropes are spaced apart in vertical direction and are firmly anchored under pretension in end anchors fixedly positioned at opposite ends of the wire ropes outside the positions for the posts, the wire ropes being positioned in receiving means arranged in the posts, detachable cover means being positioned on top of said receiving means, the said posts and the said cover means having cooperating hooking means, preventing the cover means from being thrown off the posts following the impact, when a vehicle hits the wire rope safety barrier. 
   Hereinafter the invention will be further described with reference to a non-limiting embodiment illustrated in the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates schematically a section of a wire rope safety barrier according to the invention. 
       FIGS. 2   a  and  2   b  illustrate a first embodiment of a post forming part of a wire rope safety barrier and how its foot portion is anchored by being embedded in concrete, 
       FIGS. 3   a  and  3   b  illustrate a slightly different post and how its foot is anchored by bolts to an embedded foundation plate. 
       FIG. 4  is an exploded view of the top part of a post and the components with which it cooperates. 
       FIG. 5  illustrates an end anchor to which the ends of the wire ropes are attached and tensioned. 
       FIGS. 6-8  are views from different directions showing a cover means forming part of the wire rope safety barrier according to the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  illustrates schematically a section of a wire rope safety barrier  1  according to the invention. This barrier  1  incorporates a plurality of posts  2 , which are mounted substantially vertically in footings  3 , and with a mutual spacing in the longitudinal direction of the barrier  1 . The posts  2  support a number of wire ropes  4 , which extend substantially horizontally between the posts  2 . In the embodiment shown there are four wire ropes  4  at the right hand side of the barrier and three wire ropes  4  in another embodiment shown at the left hand side, but this number can differ in view of the requirements, depending on type of road traffic, expected speeds etcetera. At the ends of the wire ropes  4 , they are anchored, at both sides of the row of posts  4 , in end anchors  5  embedded in anchor blocks  6 . The wire ropes  4  are tensioned by means of the end anchors in a manner which will be further explained in connection to  FIG. 5 , thus that they can withstand smaller collision forces. 
   In  FIG. 2   a  is shown a first embodiment of a post  2 , mainly having an I-profile and having in the intermediate beam of the I-profile a slot  7  opening in the top side of the post and extending downwards a distance somewhat exceeding the distance between the upper and the lower wire rope  4  to be fitted to the posts. In this embodiment the post  2  has a separate footing  8  in form of a plate with an upright socket  8   a . As shown in  FIG. 2   b , the footing  8  is embedded in a concrete layer  10 , with the socket projecting up from the upper surface of the concrete layer. The post  2  is anchored by being inserted from above in the socket  8   a , and then being secured by means of a bolt joint  9  extending through a bore  9   a  in socket and post. 
   In  FIG. 3   a  is shown a post  2  with a slot  7  having a base plate  11  fixedly attached thereto and in turn attached via bolts with a foundation plate  12 , which, as can be seen in  FIG. 3   b , is embedded in a concrete layer  13 . 
     FIG. 4  shows in an exploded perspective view an upper part of a post  2 , with the slot  7 . Here it is seen how the different wire ropes  4  will be positioned in the slot  7 , with spacing members  14  or distance spreaders positioned between two adjacent wire ropes  4 . There might also be arranged stiffening frames  15  around the spacing members  14 . At the top of the post  2 , above the stack of wire ropes  4 , spacing members  14  and stiffening frames  15  is attachable a top cover  16 , arranged to form a protection of the components situated in the slot  7  in the post and also for giving a protection against damages caused when the post top end hits a vehicle. The spacing members  14  are preferably made from plastic material, whereas the stiffening frames preferably are stainless steel frames. At least one opening  17  is provided in a flange in the post  2  adjacent its upper end. The function of this opening  17  will be further described hereinafter. 
   In  FIG. 5  is showed in an exploded perspective view the end anchor  5  and its associated components. In the embodiment illustrated the main body of the end anchor is a substantially rectangular sleeve, having substantially V-shaped recesses  5   a  adapted to hold end fittings  4   a  for the wire ropes  4 , and being equipped with rigging screws  4   b  for giving the wire ropes a desired preload and tension. 
     FIGS. 6-8  show in different angles a top cover  16 , as can also be seen in FIG.  4 .  FIG. 6  shows the top cover  16  from below,  FIG. 7  shows it from the longer side and  FIG. 8  shows it from above. For elucidating the structure thereof  FIGS. 7 and 8  is shown with hidden contours shown in dash lines, and it can here be seen that the top cover  16  is a shell-like member having a substantially I-shaped cross-section, and an inner size and shape corresponding to the outer shape and size of the cross-section of the post  2  (see FIG.  4 ). On the inner wall of the shell-like member  16  there is provided an inwardly directed projection  18 . This projection cooperates with the opening  17  at the upper end of the post in such a manner that it penetrates into the opening and thereby provides a locking effect between the top cover and the post, when mounted thereon. Due to the inherent flexibility of the plastic top cover, the wall thereof can flex sufficiently when the top cover is fitted to the post for allowing its projection  18  to snap into the opening  17  in the post  2 . It is thereby secured, that the top cover will not easily be thrown off the post at a sudden impact caused by a vehicle hitting the wire ropes  4  and/or a post  2 . Thereby it is in most cases prevented that the plastic top cover, and other components attached to the safety barrier will be thrown over in the lane of the oncoming traffic. 
   The invention is not limited to the embodiment illustrated in the drawings and described in connection thereto, but modifications and variants are possible within the scope of the accompanying claims.