Abstract:
A side guard fence comprises a plurality of posts arranged at a mutual distance along the edge of a carriage way and being substantially vertically anchored. The fence further comprises substantially horizontal, longitudinal fence members that are attached to the posts and are arranged at mutually spaced apart distances from each other in the vertical direction. The posts are positioned in the slope outside the carriage way or supporting reserve. In some arrangements, the horizontal fence members are anchored to the post by retaining members that are adapted to retain the horizontal fence members during forces caused by collision in a longitudinal direction of the fence members and to release the horizontal fence members when acted upon by forces generated by collisions against a post to which the horizontal fence members are attached. A method of forming a side guard fence is also disclosed.

Description:
PRIORITY INFORMATION  
         [0001]    This application is based on and claims priority to Swedish Patent Application No. 0001990-1, filed May 26, 2000, the entire contents of which are hereby expressly incorporated by reference.  
         FIELD OF THE INVENTION  
         [0002]    The present invention relates to a safety fence and, in particular, to a safety fence for use with the carriage ways of highways.  
         DESCRIPTION OF THE RELATED ART AND SUMMARY OF THE INVENTION  
         [0003]    Safety fences are known in different designs and they are often positioned between the carriage ways of highways having carriage ways separated from each other by a central reserve. Such road fences have been very successful and they have contributed to a substantial reduction of accidents between opposing vehicles on such roads.  
           [0004]    A big risk for accidents is vehicles travelling off the road towards the sides thereof. In order to reduce the risk of theses types of accidents with vehicles, large costs have been undertaken in removing trees, rocks and the like along the roads. However, this has not always proven itself to give the intended effect.  
           [0005]    In order to prevent a vehicle from ending up outside the carriage way, especially at locations of particular risk for subsequent injuries, such as, for example, at water courses, areas with large level differences, etc., it has been suggested to provide lateral road fences along particularly these dangerous portions of the road. To date, fences, which were earlier developed primarily for the central reserve, primarily have been used. As a general rule, these posts have been arranged in foundations directly adjacent the asphalt-paved carriage way (i.e., at the asphalt edge or just outside this, in the so-called supporting reserve). This means that it has not been possible to use the supporting reserve between the road embankment or the carriage way and the slope situated outside the supporting reserve, e.g., by bicyclists, or by other slow-travelling vehicles, and neither as a temporary parking area at engine failures or the like.  
           [0006]    A purpose of the present invention is to offer a side guard fence, which provides a solution to at least some of these problems. Therefore, one aspect of the present invention involves a side guard fence that comprises a plurality of posts arranged at a mutual distance along an edge of a carriage way and substantially horizontal, longitudinal fence members that are attached to the posts and are arranged at mutually spaced apart distances from each other in a vertical direction. The posts are anchored in substantially vertically direction in a slope located outside the edge of the carriage way.  
           [0007]    Another purpose of the invention is to provide a simple and reliable arrangement for anchoring the horizontal members of the fence to the posts thereof. Thus, another aspect of the invention is a side guard fence that comprises a plurality of posts arranged at a mutual distance along an edge of a carriage way. The posts are substantially vertically anchored. The fence also comprises substantially horizontal, longitudinal fence members that are attached to the posts and are arranged at mutually spaced apart distances from each other in a vertical direction. The horizontal fence members are anchored to the posts by retaining members that are adapted to retain the horizontal fence members during forces caused by collision in a longitudinal direction of the fence members and to release the horizontal fence members when acted upon by forces generated by collisions against a post to which the horizontal fence members are anchored.  
           [0008]    Still yet another aspect of the present invention involves a method of forming a side guard fence. The method comprising anchoring a series of posts in a substantially vertical direction in along an edge of a carriage way in a slope that is located outside the edge of the carriage way and anchoring a plurality of horizontal longitudinal fence members to the series of posts with retaining member that are adapted to retain the horizontal fence members during forces caused by collision in a longitudinal direction of the fence members and to release the horizontal fence members when acted upon by forces generated by collisions against a post to which the horizontal fence members are anchored.  
           [0009]    For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.  
           [0010]    All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    These and other features of the invention will now be described with reference to the drawings of the preferred embodiments, which are intended to illustrate and not to limit the invention, and in which:  
         [0012]    [0012]FIG. 1 shows schematically in a partial cross-section a post of a side guard fence having certain features and aspects according to the invention, seen in a view in the longitudinal direction of a carriage way, which also is shown only partly.  
         [0013]    [0013]FIG. 2 is a perspective view of a portion of a side guard fence of FIG. 1.  
         [0014]    [0014]FIG. 3 shows an alternate positioning of the post of the side guard fence of FIG. 1, with fence members supported by schematically shown retaining members.  
         [0015]    [0015]FIG. 4 a  shows a portion of a post equipped with a retaining member, as seen from the side.  
         [0016]    [0016]FIG. 4 b  is a front view of the post with a retaining member and a horizontal fence member supported therein.  
         [0017]    [0017]FIG. 5 a  is a perspective view of a portion of a post with another type av retaining member.  
         [0018]    [0018]FIG. 5 b  is a separate part incorporated in the retaining member according to FIG. 5 a.    
         [0019]    [0019]FIG. 6 a  is a perspective view of a portion of a post having a further type of retaining member.  
         [0020]    [0020]FIG. 6 b  is a separate part incorporated in the retaining member according to FIG. 6 a.    
         [0021]    [0021]FIG. 7 a  is a perspective view of a further post with another type of retaining member.  
         [0022]    [0022]FIG. 7 b  illustrates a post with a retaining member according to FIG. 7 a,  as seen from above.  
         [0023]    [0023]FIG. 8 a  is a perspective view corresponding to FIG. 6 a,  showing a similar post but having slightly amended retaining member, and  
         [0024]    [0024]FIG. 8 b  shows in perspective the retaining member used in FIG. 8 a.   
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    [0025]FIG. 1 schematically illustrates a portion of a paved (e.g., asphalt-paved) carriage way  1 , which at its outer edge is bordered by an edge line  2  and outside this by a supporting reserve  3 , which still is substantially horizontal. Outside the supporting reserve adjoins a slope  4 , having an inclination, which partly is determined by the terrain, but which preferably is 1:6 or bigger. In contrast to what has earlier been used, a series of posts  5  (only one of which is visible in the drawing figure) has been positioned outside the carriage way  1 , as well as outside the supporting reserve  2 , and the posts instead been positioned in the slope  4  at a distance from the supporting reserve, which distance is at most three meters. The post  5  is preferably anchored directly in the ground material of the slope without use of pre-fabricated foundations or foundations cast on site, They can preferably be rammed down or positioned in such pre-made holes, such that the portion  5   a  of the post anchored in the hole preferably shall have a depth of at least 60 centimeters.  
         [0026]    The post  5  supports together with the other posts incorporated in the fence, a number of substantially horizontally arranged fence members  6 , which, in the embodiment shown in FIG. 1, includes three parts that are preferably positioned at mutually equal vertical distances. In the embodiment illustrated, the fence members  6  can be made as steel ropes or wires. In modified embodiments, the fence members  6  can be in the form of, by way of example, thin belts or rods.  
         [0027]    [0027]FIG. 2 schematically illustrates, in perspective, a series of posts  5  of the type illustrated in FIG. 1. The posts  5  are anchored in a slope  4  outside the supporting reserve  3  at a road and have three horizontal fence members  6  arranged at substantially equal distances from each other in vertical direction.  
         [0028]    [0028]FIG. 3 shows in a view corresponding to FIG. 1 the positioning of the post  5  at a certain distance from the supporting reserve. In this embodiment, the post  5  includes three horizontal fence members  6  as in FIG. 1. In contrast, a post  5 ′, which is illustrated with dash and dot lines, is positioned in the slope  4  farther away from the supporting reserve  3 . Such a post  5 ′ may need a larger number of horizontal fence members  6 ′. In the illustrated embodiment, the post  5 ′ preferably includes four horizontal members  6 ′ that are arranged such that the mutual distance between the adjacent members  6 ′ is about the same as the distance between the members of the post  5 . In this manner, it is ascertained that vehicles travelling off the road at high speeds will be caught by means of the upper horizontal fence members  6 ,  6 ′, whereas vehicles driving off at lower speed and/or at a low angle to the fence, will hit the lower fence members  6 ,  6 ′.  
         [0029]    [0029]FIG. 4 an and  4   b  illustrate an embodiment of a retaining member for a horizontal fence member  6 , which, by way of example, is illustrated as a steel rope. The retaining member in this case is comprises by an inclined slot  7 , cut obliquely from above and downwards in the wall of the post  5 . The slot  7  is shown in FIG. 4 a  from the side and in FIG. 4 b  from the front. A steel rope  6  is inserted in the slot  7 , which in the side perspective is shaped almost as a horseshoe. Due to this design of the retaining member  7 , a force caused by a collision in the longitudinal direction of the rope  6  will result in that the rope  6  is retained due to the force component urging the rope against the wall of the slot. At collision the car is caught by the horizontal fence members  6  or the steel ropes and when the car hits a post  5 , this will be bent in the direction of travel of the car and the steel ropes  6  and the posts  5  are separated from each other.  
         [0030]    [0030]FIG. 5 a  and  5   b  illustrate another design of post  5  and retaining member  8 . As shown in FIG. 5 a , a post  5  is provided with a longitudinal slot Sa and a number of substantially keyhole shaped openings  8  situated above each other. The openings  8 , pair by pair, serve to receive a cleat-formed hook  9 , which has bigger portions  10  at its ends. These bigger portions  10  have a size allowing them to pass through the upper, wider part of each keyhole  8 , whereas, after they have been moved down in the more narrow part of each keyhole opening, they cannot be pulled out of the openings  8 . When the fence is hit by a car these retaining members act in a manner corresponding to the slot  7  according to FIGS. 4 a  and  4   b , whereby the force acting perpendicularly to the post causes the hook  9  and the walls of the holes  8  to be deformed such that their interconnection is interrupted.  
         [0031]    It shall be observed that the posts according to FIG. 4 a  and FIG. 5 a  have both been shown with only one retaining member  7  and  8 ,  9  respectively but in accordance with what is earlier said, it is evident that each post can have a number of retaining members arranged in vertical direction, which, preferably, correspond at least to the number of horizontal fence members  6  that are needed to be used in every individual case.  
         [0032]    [0032]FIGS. 6 a  and  6   b  illustrate another embodiment of a retaining member at a post  5 . In this embodiment, the member is comprises a number of slots  11  shaped as a reversed “figure one”. In each slot  11  is inserted a cleat-like hook  12 , having ends  13  bent out in opposite directions.  
         [0033]    As with the previous embodiment, when forces act in the longitudinal direction of the fence members, the fence members can move in relation to the retaining members  11 ,  12  and to the posts  5 . In contrast, when a car hits a post and the post is bent in the direction of travel of the car, at the same time as the car is caught by the horizontal fence members, the ends  13  of the hook or the walls of the hole  11  are deformed and the hook comes loose from the post  5 .  
         [0034]    [0034]FIGS. 7 a  and  7   b  illustrate another embodiment. In this embodiment, the tubular post  5  has two axially extending slots  14 , wherein the horizontal fence members or steel ropes  6  are positioned. The mutual distance between the steel ropes  6  is determined by spacer members  15 , which are positioned in one or both slots.  
         [0035]    [0035]FIGS. 8 a  and  8   b  illustrate another embodiment. In this embodiment, the post  5  has the same type of holes  11  for retaining members  12 ′ as the post in FIG. 6 a.  However, in this embodiment, the retaining members  12 ′ differ slightly from those according to FIG. 6 b.  Specifically, when the horizontal fence members  6 , in form of steel ropes are mounted in the retaining members, the steel ropes are wound off from tractor-borne rollers on which very long and therefore heavy strands of the rope are stored. With the hook member shown in FIG. 6 b , the rope must wound off and positioned on the ground along the series of posts. It is then necessary for operators to walk along the fence under construction, and fit a hook member  12  around the rope  6  for every post and then to lift the rope up to the hole  11  in the post with the substantial weight from the rope. This is a heavy and tiring job, and it is also quite time-consuming, in view of the large number of retaining positions.  
         [0036]    The hook member  12 ′ in the embodiment according to FIG. 8 b , has a further bend  16  positioned adjacent one of its ends  13 . With aid of this additional bend  16  it is possible to position the retaining member or the hook  12 ′ in the hole  11  in the post  5  such as shown in the lower hole  11  in FIG. 8 a.  With hooks  12 ′ thus positioned in all slots  11  in all posts  5  for a distance corresponding to the length of the steel rope  6  on a storage roller, it is possible to lay the steel rope  6  directly in the hook  12 ′ such as shown in the upper position of the slot  11  in FIG. 8 a . Some manual work may be required in guiding the steel rope to come to rest in the hook member  12 ′, but the heavy work for lifting the hooks with the weight of the steel rope is eliminated. From the position shown in the upper part of FIG. 8 a , it is comparatively easy work to swing up the free end of the hook  12 ′ and insert it in the upper part of the slot  11  and thereupon to let it slide down until it is positioned in the same manner as the retaining member  12 , shown with dash and dot lines in FIG. 6 a.    
         [0037]    Of course, the foregoing description is that of a preferred construction having certain features, aspects and advantages in accordance with the present invention. Various changes, combinations, sub-combinations and modifications may be made to the above-described arrangements without departing from the spirit and scope of the invention, as defined by the appended claims.