Patent Publication Number: US-9416508-B2

Title: Terminal arrangement for a road rail

Description:
This application is a National Stage Application of PCT/SE2010/051235, filed 10 Nov. 2010, which claims benefit of Serial No. 0950871-4, filed 17 Nov. 2009 in Sweden and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     TECHNICAL FIELD 
     The present invention relates to a terminal arrangement for a road rail with a rail profile, in which arrangement a terminal guiding device is movable along the road rail under the influence of kinetic energy from a vehicle hitting the terminal guiding device and which is provided with a ground anchor. It also relates to a method for absorbing kinetic energy from a vehicle hitting a terminal arrangement at the end of a road rail. 
     BACKGROUND OF THE INVENTION 
     A road rail comprising a rail profile, typically a metal profile, mounted on rail posts can be arranged beside a road for preventing vehicles from leaving the road and thereby enhances the road safety. A vehicle that hits the road rail along its length will normally not be seriously damaged. However, it may be very dangerous to hit the end of such a road rail without any safety measures. A suitably designed terminal arrangement may decrease the damages at a collision between a vehicle and the end of a road rail. 
     A terminal arrangement as defined above is disclosed in SE-C-513 130. In this design there is a terminal guiding device moving along the rail profile when hit by a vehicle. The terminal guiding device has a deformation device for the rail profile as well as an internal channel for bringing down the deformed rail profile to the ground level, so that the vehicle, gradually braked by the terminal guiding device, can pass over it without being damaged or turned over. There is a wire connection between the end of the rail profile and a ground anchor in line with the road rail. 
     The main object of the invention is to improve and simplify such a terminal arrangement as defined above. It is hereby of great importance for the safety that possible force components trying to raise the terminal guiding device are obviated and also that the rail profile is brought down to the ground level for obviating further damages to the hitting vehicle. 
     THE INVENTION 
     This is according to the invention attained in that a terminal profile, constituting a prolongation of the rail profile, extends within the terminal guiding device obliquely down to the ground anchor, where it is attached, and that means for deforming the terminal profile and eventually the rail profile and thus for absorbing kinetic energy are provided in the terminal guiding device. 
     The terminal profile may preferably have the same cross sectional shape as the rail profile and be longitudinally slotted in order to enhance its deformation properties. However, it may be possible to have other shapes and appearances of the terminal profile. 
     A ground attachment is preferably attached to the ground anchor and has a plate, which extends in the direction towards the road rail and to which the terminal profile is attached. The terminal guiding device, which has the general shape of a downwardly open U, can be provided with a cross piece under the plate. By this arrangement the terminal guiding device will be guided initially by the plate for movement along the ground. 
     The terminal guiding device may also be provided with another cross piece over the plate for deforming the terminal profile and thus absorbing energy. The deformation may be controlled by the position of this cross piece and the distance between the two cross pieces. 
     The terminal guiding device may be connected by friction force to the ground attachment by means of screw joints. In a rest position the terminal guiding device will hereby be fastened to the ground attachment but will be separated therefrom, when a vehicle hits it with a certain force. 
     The terminal guiding device may preferably also have a cross piece at an input end for the rail profile, whereas the terminal profile may have an elbow in the terminal guiding device in the vicinity of the input end. Hereby, energy is also absorbed at the input end, and the terminal profile and eventually the rail profile, to which it is attached, will be forced down towards the ground as desired. 
     A first rail post of the road rail is preferably arranged in the vicinity of the input end of the terminal guiding device in the rest position of the latter, so that it will be hit and brought down to the ground at an early stage after a vehicle has hit the terminal guiding device. 
     The terminal guiding device is preferably provided with a terminal end portion, which a colliding vehicle hits. It may have a suitable construction for causing as little damage to the vehicle as possible and for preventing upwardly directed forces to occur. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in further detail below under reference to the accompanying drawings, in which 
         FIG. 1  is a side view of a road rail with a terminal arrangement according to the invention, 
         FIG. 2  is a corresponding view, also illustrating ground anchorings for posts of the road rail and for the terminal arrangement, 
         FIG. 3  is a view corresponding to  FIG. 2  of the terminal arrangement to a larger scale, 
         FIG. 4  is a view to an even larger scale of an end portion of the terminal arrangement, and 
         FIG. 5  is an end view of the terminal arrangement. 
     
    
    
     DETAILED DESCRIPTION 
     A metal road rail may as shown in  FIG. 1  comprise tubular posts I and a rail profile  2  attached to the posts. The rail profile  2  may have a prismatic or ellipsoidal cross sectional shape. Such a road rail is disclosed in the copending Swedish Patent Application No 0801271-8. The posts  1  may as shown in  FIG. 2  be anchored in the ground. Their cross-sectional shape may be generally cylindrical, but they are preferably flattened close to the ground, so that they are bent there in a controlled way when exposed to forces generally in the direction of the road rail as a result of a collision with a vehicle on the road. 
     The invention is concerned with a terminal arrangement  3  for such a road rail. This terminal arrangement  3  provided at the free end of a road rail has the purpose of protecting a vehicle hitting the end of the road rail generally in its longitudinal direction. 
     A strong ground anchor  4  is provided for the terminal arrangement  3 . A ground attachment  5  is attached to this ground anchor  4 , preferably by screws  6 . The ground attachment  5  has a plate  7  extending in the longitudinal direction towards the road rail. 
     A terminal profile  8 , preferably but not necessarily of the same material and with the same cross-sectional shape as the rail profile  2  is firmly attached to the plate  7  and extends obliquely upwards to an elbow  8 ′ and then in the same direction as the rail profile  2  and is connected to the latter by a joint  9 . The terminal profile  8  may be supported by a rail post  1  in the vicinity of the elbow  8 ′. The distance between this rail post  1  and the joint  9  may be in the order of 2 meters and the distance between neighboring rail posts  1  in the road rail some 6 meters. The terminal profile  8  is preferably longitudinally slotted in order to improve its deformation characteristics. 
     A terminal guiding device  10  is connected at a first end to the left in the Figures to the ground attachment  5  and extends in the direction of the rail profile  2  over and past the elbow  8 ′ of the terminal profile  8 . The longitudinal portion of the terminal guiding device  10  has a downwardly open U-shape. 
     At its input end for the terminal profile  8  the terminal guiding device  10  is provided with a first cross piece  11 , so that a closed opening is created. 
     Towards its opposite end the downwardly open terminal guiding device  10  is extended down to the ground attachment  5 . A second cross piece  12  connects the two legs of the terminal guiding device  10  below the plate  7 , and an obliquely arranged, third cross piece  13  connects the two legs of the terminal guiding device  10  over the plate  7 . This third cross piece  13  may be regarded as the main means for deforming the terminal profile  8  and thus for absorbing kinetic energy. The position of the third cross piece  13  and its distance to the second cross piece  12  (and thus the plate  7 ) determines the deformation of the terminal profile  8  and thus the kinetic energy absorbed. 
     The terminal guiding device  10  is connected to flanges of the ground attachment  5  by means of two screw joints  14  in horizontal open grooves in the legs of the terminal guiding device  10 , so that the latter may move to the right in the Figures if exposed to a force exceeding the friction force of the screw joints  14 . 
     At its end to the left in the Figures the terminal guiding device  10  is provided with a terminal end portion  15 . A colliding vehicle hits this end portion  15 , which is designed in such a way that the hitting vehicle is damaged to a minimum extent. Its design is also such that no upwardly directed forces are generated. 
     If a vehicle hits the terminal end portion  15  with a certain speed, the terminal guiding device  10  will be freed by the screw joints  14  to move to the right in the Figures along the terminal profile  8  (and later on the rail profile  2 ). Initially, the plate  7  will guide the movement along the ground. After a short movement the first rail post  1  will be bent down, and the third cross piece  13  will engage the terminal profile  8  and deform it downwards against the plate  7 . After further movement the terminal guiding device  10  will also reach the rail profile  2  with its input end. The combined action of the deformation at the third cross piece  13  and at the input end of the terminal guiding device  10 , absorbing energy from the vehicle having hit the terminal end portion  15 , will lead to decreasing speed of the movement to the right of the terminal guiding device  10 . During the movement first the terminal profile  8  and later the rail profile  2  (as well as certain rail posts  1 ) will be brought down to the ground, and the vehicle having hit the terminal arrangement  3  will move freely over it without being damaged or affected in its movements on its wheels, until it is brought to a standstill. 
     Modifications are possible within the scope of the appended claims. Especially, it shall be noted that the terminal profile  8  need not be a profile with the same cross sectional shape as the rail profile but may have any other shape and appearance, for example a flat bar or a rod.