Patent Publication Number: US-11021843-B2

Title: Energy absorbing post having sliding rail assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Korean Patent Application No. 10-2018-0164454, filed on Dec. 18, 2018, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a crashworthy post capable of reducing collision energy generated when a vehicle makes a collision. 
     2. Description of the Related Art 
     A crashworthy post for a telegraph pole, a light pole, a road sign or the like includes a vertical body and a collision energy absorbing member. If a vehicle collides with the crashworthy post, the body moves to transfer the force to the collision energy absorbing member. Accordingly, the collision energy absorbing member is compressively deformed or crushed to dissipate the collision energy of the vehicle. In the crashworthy post, it is very important that the body moves while decelerating slowly. As the body decelerates rapidly, the impact force applied to an occupant of the colliding vehicle increases proportionately. Thus, it is necessary to design the colliding vehicle and the body such that the colliding vehicle does not rapidly decelerate while the collision energy is being dissipated by the collision energy absorbing member, in order to protect the occupant more safely. 
     Conventionally, rubber or synthetic resin is used for the collision energy absorbing member. However, after the body crushes or compressively deforms the collision energy absorbing member, the body decelerates rapidly or decelerates at an irregular rate due to residues of the deformed or crushed collision energy absorbing member. Due to this phenomenon, a significant impact force may be applied to the occupant of the colliding vehicle. 
     SUMMARY 
     The present disclosure is designed to solve the problems of the conventional art, and the present disclosure is directed to preventing a body of a crashworthy post or a colliding vehicle from rapidly decelerating due to residues of a collision energy absorbing member, after the collision energy absorbing member is compressively deformed or crushed. In particular, the present disclosure is directed to protecting an occupant of the vehicle more safely by designing the body to decelerate at a predetermined rate to prevent a great impact from being applied to the occupant when the vehicle makes a collision. 
     In order to accomplish the above object, the present disclosure provides a crashworthy post, which includes a base member having a sliding rail assembly embedded therein, a post body installed to the base member, and a base plate provided to a lower end of the post body. 
     In the present disclosure, the compressive deforming pipe performs excellently as a collision energy absorbing member. Thus, the impact applied to an occupant is reduced when a vehicle makes a collision, thereby ensuring the occupant safety. In particular, in the present disclosure, the compressive deforming pipe is compressively deformed not rapidly but gradually. Thus, it is possible to prevent the collision energy from being rapidly dissipated, thereby preventing the body and the colliding vehicle from rapidly decelerating. 
     In particular, in the present disclosure, the compressive deforming pipe is prevented from being rapidly crushed or from being compressively deformed only in the longitudinal direction. In addition, the compressive deforming pipe is not crushed or deformed to form fragments. Thus, the movement of the body is not disturbed due to residues such as fragments of the compressive deforming pipe, thereby preventing the moving body from being rapidly or irregularly decelerated. That is, in the present disclosure, after the collision of the vehicle, the body moves to be slowly decelerated at a uniform rate, and thus the vehicle may be safely stopped without applying a large impact to the occupant of the colliding vehicle. 
     In addition, in the present disclosure, only a deformed portion of the compressive deforming pipe may be replaced with a new one, and thus the crashworthy post may be restored to be reused quickly and easily. Thus, even after a vehicle makes a collision accident, it is possible to quickly reinstall the crashworthy post, thereby maintaining a safe road environment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view showing a conventional crashworthy post. 
         FIG. 2  is a schematic perspective view showing an assembled crashworthy post according to the first embodiment of the present disclosure in an assembled state. 
         FIG. 3  is a schematic perspective view showing a sliding rail assembly provided in the first embodiment of the present disclosure. 
         FIG. 4  is a schematic rear sectioned view showing the sliding rail assembly, taken along the arrow A-A of  FIG. 3 . 
         FIG. 5  is a schematic rear sectioned view showing the sliding rail assembly, taken along the arrow B-B of  FIG. 3 . 
         FIG. 6  is a schematic perspective view showing the sliding rail assembly of  FIG. 3 , from which a sliding support member is excluded to depict a compressive deforming pipe. 
         FIG. 7  is a schematic side view showing an example of the compressive deforming pipe provided in the present disclosure. 
         FIGS. 8 and 9  are schematic perspective views corresponding to  FIG. 6 , respectively showing the sliding rail assembly at which the compressive deforming pipe installed thereto is modified. 
         FIG. 10  is a schematic perspective view showing a base plate of the crashworthy post, which is assembled to the sliding rail assembly of  FIG. 3 . 
         FIGS. 11 and 12  are schematic perspective views showing only the post body and the base plate according to the first embodiment of the present disclosure in different viewpoints. 
         FIGS. 13 and 14  are a schematic front view showing the post body and the base plate of  FIG. 11  along the arrow J of  FIG. 12  and a schematic planar sectioned view along the arrow C-C. 
         FIG. 15  is a schematic perspective view showing the base plate according to the first embodiment of the present disclosure, which is assembled to the sliding rail assembly of  FIG. 3 . 
         FIG. 16  is a schematic longitudinal sectioned view, taken along the arrow E-E of  FIG. 15 . 
         FIGS. 17, 18, 19, and 20  are schematic perspectives view showing for sequentially illustrating a process of assembling each pressing member to the compressive deforming pipe, respectively. 
         FIGS. 21 and 22  are schematic side views showing the states of  FIGS. 19 and 20 , respectively. 
         FIG. 23  is a schematic perspective view showing a finally installed state of the crashworthy post according to the first embodiment of the present disclosure. 
         FIG. 24  is a schematic perspective view showing only the sliding rail assembly, the base plate and the compressive deforming pipe from  FIG. 23 . 
         FIG. 25  is a schematic longitudinal sectioned view, taken along the arrow F-F of  FIG. 24 . 
         FIG. 26  is a schematic perspective view corresponding to  FIG. 23 , showing a state where the post body according to the first embodiment of the present disclosure is moved rearward over a spaced distance. 
         FIG. 27  is a schematic view showing that the pressing member of the present disclosure is moved rearward to dissipate vehicle collision energy. 
         FIG. 28  is a schematic perspective view corresponding to  FIG. 11 , showing a state where a pressing member is provided to the base plate according to the second embodiment of the present disclosure. 
         FIG. 29  is a schematic front view corresponding to  FIG. 13(A) , showing the structure of  FIG. 26 . 
         FIG. 30  is a schematic perspective view corresponding to  FIG. 3 , showing the sliding rail assembly provided in the second embodiment of the present disclosure. 
         FIG. 31  is a schematic perspective view corresponding to  FIG. 14 , showing a state where the base plate according to the second embodiment of the present disclosure is assembled to the sliding rail assembly. 
         FIG. 32  is a schematic longitudinal sectioned view, taken along the arrow W-W of  FIG. 31 . 
         FIGS. 33 and 34  are schematic exploded perspective views for illustrating that the base plate and the sliding rail assembly according to the second embodiment of the present disclosure are assembled in different ways. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the accompanying drawings. Although the present disclosure is described with reference to the embodiment shown in the drawings, this is just an example, and the technical idea of the present disclosure and its essential configuration and operation are not limited thereto. In this specification, the term “rearward” refers to a direction in which a vehicle collides toward a post body, namely a direction in which the vehicle moves to approach the post. That is, in  FIG. 2 , the direction indicated by the arrow K is the “rearward” direction. Thus, in this specification, the term “forward” refers to a direction facing the vehicle from the post body when the vehicle collides toward the post body, namely a direction opposite to the rearward direction. In addition, the term “longitudinal direction” refers to a direction connecting by the forward direction and the rearward direction, and the term “lateral direction” refers to a direction orthogonal to the longitudinal direction on the plane. 
       FIG. 2  is a schematic perspective view showing a crashworthy post  100  according to the first embodiment of the present disclosure. The crashworthy post  100  includes a base member  2  and a post body  1 . The body  1  stands up vertically on the base member  2  to be capable of sliding rearward. 
     The base member  2  includes a sliding rail assembly  5  and a concrete member  20 . The sliding rail assembly  5  is integrated with the concrete member. The concrete member  20  may have a slab. The concrete member  20  may be a cast-in-place concrete structure, but may also be a precast structure. 
       FIG. 3  shows the sliding rail assembly  5  of  FIG. 2  in a state of being not embedded in the concrete member  20  of the base member  2 .  FIG. 4  is a schematic sectioned view showing a rear side of the sliding rail assembly  5 , taken along the arrow A-A of  FIG. 3 .  FIG. 5  is a schematic sectioned view showing the rear side of the sliding rail assembly  5 , taken along the arrow B-B of  FIG. 3 . In  FIG. 6 , the sliding support member  50  is not depicted to show a compressive deforming pipe  40  provided to the sliding rail assembly  5 . 
     The sliding rail assembly  5  includes a sliding support member  50 , a vertical support member  51 , and a bottom member  52 . The sliding support member  50  is made of a pair of members arranged in parallel on the same plane with a lateral interval and elongated in the longitudinal direction. The sliding support member  50  may be made of a flat plate. The sliding support member  50  supports the base plate  10  provided at the lower end of the post body  1 . The sliding support member  50  functions as a sliding rail which allows the base plate  10  to slide rearward. 
     In the first embodiment of  FIGS. 2 to 5 , a widening cut portion is formed at the sliding support member  50 . The pair of sliding support members  50  are cut to a predetermined width in a predetermined length region in the longitudinal direction from the forward end of the sliding rail assembly  5 . By doing so, the widening cut portion having a larger lateral interval between the sliding support members  50  than that of the other regions is formed in the predetermined length region. Through the widening cut portion, a pressing member  11  may be easily positioned between the vertical support members  51  by vertically moving downward. However, the widening cut portion is an optional configuration. 
     The vertical support member  51  is a member that supports the sliding support member  50  to be positioned at a vertical distance from the bottom member  52 . The vertical support member  51  is elongated in the longitudinal direction and is provided in a pair so that the pair of vertical support members  51  are provided vertically with a lateral interval. The pair of vertical support members  51  are integrally installed to the upper surface of the bottom member  52  to stand up vertically. The two vertical support members  51  support two sliding support members  50 , respectively, and for this, the upper end of the vertical support member  51  is integrally coupled with the lower surface of the sliding support member  50 . In the first embodiment illustrated in the figures, the lateral interval between the two vertical support members  51  is greater than the lateral interval between the two sliding support members  50 . Each vertical support member  51  may be made of a plate member. The space between the two vertical support members  51  corresponds to a guide trough  3 . 
     The bottom member  52  is coupled to the lower end of the vertical support member  51  and may be made of a flat plate. If necessary, a reinforcing rib  53  may be provided between the bottom member  52  and the outer surface of the vertical support member  51 . A compressive deforming pipe  40  corresponding to a collision energy absorbing member is located at the guide trough  3 . 
       FIG. 7  is a schematic side view showing an example of the compressive deforming pipe  40  provided in the present disclosure. The compressive deforming pipe  40  is a tubular member which is elongated in the longitudinal direction and has a hollow, and may be made of, for example, steel. In a state where the pressing member  11  surrounds the outer circumference of the compressive deforming pipe  40 , the pressing member  11  moves rearward to press the compressing compressive deforming pipe  40  so that the compressing compressive deforming pipe  40  is deformed. The collision energy is dissipated by the compressive deformation of the compressive deforming pipe  40 . In order to more efficiently dissipate the collision energy, in the present disclosure, the compressive deforming pipe  40  may be configured such that its sectional diameter gradually changes from the front to the rear. That is, the compressive deforming pipe  40  has a larger sectional diameter in the rear portion thereof than the front portion. As the pressing member  11  surrounding the outer circumference of the front portion of the compressive deforming pipe  40  moves rearward, the sectional size of the compressive deforming pipe  40  decreases to dissipate the collision energy. 
     The compressive deforming pipe  40  according to the embodiment illustrated in  FIG. 7  is classified into a spaced distance forming region L 1  having a small diameter, a diameter changing region L 2  changing from a small diameter to a large diameter, and a compressive deforming region L 3  having a large diameter, from the front to the rear in the longitudinal direction. In the diameter changing region L 2 , the outer surface of the compressive deforming pipe  40  is inclined. In the compressive deforming pipe  40  according to the embodiment illustrated in the figures, the compressive deforming region L 3  has a constant sectional diameter as a whole. However, if necessary, the compressive deforming region L 3  may be made to have a sectional diameter gradually increasing rearward. In the compressive deforming pipe  40  of  FIG. 7 , the spaced distance forming region L 1  also has a constant sectional diameter as a whole. However, the spaced distance forming region L 1  may also have a sectional diameter gradually increasing rearward, except for a region where the pressing member  11  is installed first. 
     The compressive deforming pipe  40  is disposed at the guide trough  3  formed by the space between the two vertical support members  51 . The compressive deforming pipe  40  should be spaced apart from the bottom of the guide trough. In order to dissipate the vehicle collision energy, the compressive deforming pipe  40  should be disposed not to move in the longitudinal direction. The compressive deforming pipe  40  may be arranged in the form of a cantilever whose front and rear ends are fixed and whose remaining part is spaced apart from the bottom. 
     For this, in the first embodiment of the present disclosure, the spaced distance forming region L 1  (a region corresponding to the spaced distance in  FIG. 1 ) of the compressive deforming pipe  40  is divided into a front fixing end  41  and a continuous portion  42  continuously assembled to the front fixing end  41 . That is, in the present disclosure, the spaced distance forming region L 1  of the compressive deforming pipe  40  may be divided into the front fixing end  41  corresponding to the foremost portion of the compressive deforming pipe  40  and the continuous portion  42  continuously assembled thereto. In order to prevent the compressive deforming pipe  40  from moving in the longitudinal direction, in the first embodiment of the present disclosure, the front fixing end  41  is coupled with a fixing part  410 , the fixing part  410  is integrally coupled with the sliding rail assembly (specifically, the bottom member), and the continuous portion  42  is securely assembled to the front fixing end  41 . Through this configuration, the compressive deforming pipe  40  is disposed in the form of a cantilever at the guide trough  3  in a state where the front fixing end  41  is fixed by the fixing part  410  and elongated in the rearward direction. If necessary, a spacer  420  may be installed to the upper surface of the bottom member  52  inside the guide trough  3  so that the compressive deforming pipe  40  is placed in the spacer  420 . 
     In the first embodiment of the present disclosure, the front end of the compressive deforming pipe  40  is fixed by the fixing part  410 , and the other portion of the compressive deforming pipe  40  is positioned to be suspended in the air inside the guide trough  3 . When the outer surface of the compressive deforming pipe  40  is pressed and compressively deformed by the pressing member  11 , the compressive deforming pipe  40  itself is prevented from moving in the longitudinal direction, and it is naturally allowed that the compressive deforming pipe  40  expands in the longitudinal direction. 
       FIG. 8  is a schematic perspective view corresponding to  FIG. 6 , showing the sliding rail assembly  5 , where the installation configuration of the compressive deforming pipe  40  is modified. In  FIG. 8 , the spaced distance forming region L 1  of the compressive deforming pipe  40  is divided into a front fixing end  41  and a continuous portion  42 . The front fixing end  41  is coupled to the fixing part  410 . The length of the compressive deforming pipe  40  is longer than the bottom member  52 , and the fixing part  410  is fixed to the ground at a front position of the bottom member  52 . Though not shown in the figures, when fixing the front fixing end  41  of the compressive deforming pipe  40 , the fixing part  410  may not be installed to the ground or the bottom member  52  but be installed between the sliding support member  50  and the front fixing end  41  or between the vertical support member  51  and the front fixing end  41 . 
     The fixing part  410  may be coupled to the rear end of the compressive deforming pipe  40 .  FIG. 9  is a schematic perspective view corresponding to  FIG. 6 , showing the sliding rail assembly  5  where the installation configuration of the compressive deforming pipe  40  is modified. As shown in  FIG. 9 , the fixing part  410  is coupled to the rear end of the compressive deforming pipe  40 . The fixing part  410  is fixed to the ground or the bottom member  52 . By doing this, the compressive deforming pipe  40  may be disposed at the guide trough  3  in the form of a cantilever having a fixed rear end. In this case, it is not necessary to divide the spaced distance forming region L 1  of the compressive deforming pipe  40  into the front fixing end  41  and the continuous portion  42 . 
       FIG. 10  shows a state where the post body  1  of the crashworthy post and the base plate  10  provided at the lower end thereof are assembled to the sliding rail assembly  5  of  FIG. 3  according to the first embodiment of the present disclosure.  FIGS. 11 and 12  show the post body  1  and the base plate  10  according to the first embodiment of the present disclosure, respectively.  FIG. 13  is a schematic front view showing the post body  1  and the base plate  10  along the arrow J of  FIG. 12 .  FIG. 14  is a schematic planar sectioned view showing the pressing member  11  along the arrow C-C of  FIG. 13 . 
     The post body  1  is a pillar-shaped member to which a road sign or the like is installed. The base plate  10  is integrally provided to the lower end of the post body  1 . The base plate  10  is a plate member and is disposed such that the lower surface of the base plate  10  comes into close contact with the upper surface of the sliding support member  50 . Thus, the post body  1  is installed to the sliding support member  50  to vertically stand up. The pressing member  11  is integrally provided to the lower surface of the base plate  10 . The pressing member  11  surrounds the outer circumference of the compressive deforming pipe  40 . While the post body  1  and the base plate  10  are moving rearward due to the collision of the vehicle, the pressing member  11  presses and deforms the compressive deforming pipe  40 . The pressing member  11  includes an outer frame member  18  having a perforated portion  180  formed at the center thereof to surround the outer circumference of the compressive deforming pipe  40 . A close pressing member  16  is provided to the inner surface of the perforated portion  180  of the outer frame member  18  to make close contact with the outer circumference of the compressive deforming pipe  40  and press and deform the compressive deforming pipe  40 . The close pressing member  16  may have a semicircular pillar shape. The close pressing member  16  is installed such that a convex curved portion of the semicircular pillar faces the center of the perforated portion  180 . The close pressing member  16  is provided in plurality. 
     In the first embodiment of the present disclosure, the pressing member  11  is connected to the base plate  10  by a hanger member  17 . Thus, the pressing member  11  is integrally provided to be suspended downward from the lower surface of the base plate  10 . The hanger member  17  is located in the interval between the pair of sliding support members  50 . When the post body  1  moves rearward, the hanger member  17  moves rearward by passing through the interval between the pair of sliding support members  50 . However, hanger member  17  is optional. The outer frame member  18  may also be coupled in direct contact with the lower surface of the base plate  10 . 
       FIG. 15  is a schematic perspective view showing a state where the base plate  10  is assembled to the sliding rail assembly  5  of  FIG. 3  according to the first embodiment of the present disclosure.  FIG. 16  is a schematic longitudinal sectioned view along the arrow E-E of  FIG. 15 .  FIGS. 17, 18, 19 and 20  are schematic perspective views for sequentially illustrating a process of assembling the pressing member  11  to the compressive deforming pipe  40 .  FIGS. 21 and 22  are schematic side views showing the states of  FIGS. 19 and 20  in a lateral form, respectively. In  FIGS. 15 and 16 , the post body  1  is not depicted for convenience, and in  FIGS. 16, 17, 18, 19, 20, 21 and 22 , the post body  1  and the base plate  10  are also not depicted for convenience. 
     The base plate  10  is coupled to the lower end of the post body  1 . The pressing member  11  is coupled to the lower surface of the base plate  10 . The outer frame member  18  surrounds the outer circumference of the compressive deforming pipe  40 , and simultaneously the base plate  10  is placed on the upper surface of the sliding support member  50 . In the first embodiment of the present disclosure, as shown in  FIG. 17 , the spaced distance forming region L 1  of the compressive deforming pipe  40  is divided into the front fixing end  41  and the continuous portion  42 . At the position where the widening cut portion of the sliding support member  50  is formed, if the base plate  10  is placed on the upper surface of the sliding support member  50 , the pressing member  11  vertically passes downward through the widening cut portion and is positioned between the two vertical support members  51 . In the first embodiment of the present disclosure, since the widening cut portion is formed at the sliding support member  50 , the pressing member  11  may be very easily positioned in the space between the vertical support members  51  by simply placing the base plate  10  on the sliding support member  50 . 
     Next, as shown in  FIG. 18 , the pressing member  11  is moved forward or rearward in the longitudinal direction. Accordingly, the front fixing end  41  or the continuous portion  42  is interposed in the perforated portion  180  of the outer frame member  18 . As shown in  FIGS. 19 and 21 , the pressing member  11  is moved rearward in the longitudinal direction so that the continuous portion  42  is interposed in the perforated portion  180  of the outer frame member  18 , whereby the outer frame member  18  surrounds the outer circumference of the continuous portion  42 . As an alternative, as shown in  FIGS. 20 and 22 , the pressing member  11  may be moved forward in the longitudinal direction so that the front fixing end  41  penetrate the perforated portion  180  of the outer frame member  18 , whereby the outer frame member  18  surrounds the outer circumference of the front fixing end  41 . Next, the front fixing end  41  and the continuous portion  42  are assembled again and firmly integrated so as to be continuous with each other as shown in  FIG. 15 . Through the above process, the outer frame member  18  of the pressing member  11  is installed to surround the outer circumference of the compressive deforming pipe  40  in the spaced distance forming region L 1  of the compressive deforming pipe  40 . 
     In the first embodiment of the present disclosure, as described above, the base plate  10  and the sliding rail assembly  5  may be assembled in a state where the sliding rail assembly  5  is installed to the base member  2 . That is, after the base member  2  is made such that the sliding rail assembly  5  is embedded in and integrated with the concrete member  20 , the post body  1  including the base plate  10  and the pressing member  11  may be assembled to the sliding rail assembly  5 . By doing so, it is possible to further enhance the convenience of work. 
     After the pressing member  11  is installed to surround the outer circumference of the compressive deforming pipe  40 , it is desirable to move the pressing member  11  rearward in the longitudinal direction so that the pressing member  11  deviates from a position where the widening cut portion of the sliding support member  50  is formed.  FIG. 23  is a schematic perspective view showing a state where the post body  1  is completely installed to the sliding rail assembly  5  provided to the base member  2  according to the first embodiment of the present disclosure.  FIG. 24  is a schematic perspective view showing only the sliding rail assembly  5 , the base plate  10  and the compressive deforming pipe  40  of  FIG. 23 , except for the base member  2  and the post body  1 .  FIG. 25  is a schematic longitudinal direction sectioned view along the arrow F-F of  FIG. 24 . 
     As shown in  FIGS. 18 to 20 , at a position where the pressing member  11  does not have the widening cut portion, the lateral interval between the sliding support members  50  is smaller than the lateral width of the outer frame member  18 . Thus, if the pressing member  11  is at the position without the widening cut portion, the sliding support member  50  is present above the outer frame member  18  of the pressing member  11 . In other words, the pressing member  11  is positioned below the pair of sliding support members  50 . Thus, the post body  1  may be prevented from being pulled up while the pressing member  11  is moving rearward. Thus, in a state where the hanger member  17  is interposed in the interval between the base plates  10  or while the hanger member  17  is moving rearward, even if a pull force to pull the post body  1  vertically upward is applied due to a wind load or the like, the pressing member  11  is blocked by the sliding support member  50  so that it is not pulled upward but maintains a very stable state. 
     In a state where the crashworthy post  100  is completely installed by assembling the base member  2  and the post body  1 , if the vehicle collides with the post body  1  of the crashworthy post  100 , the vehicle, the post body  1  and the base plate  10  begin to move rearward.  FIG. 26  is a schematic perspective view showing a state where the post body  1  moves rearward over the spaced distance, in the crashworthy post  100  according to the first embodiment of the present disclosure. Since the sliding support member  50  of the sliding rail assembly  5  is elongated rearward, the base plate  10  is pushed rearward in a state where its lower surface is in contact with the upper surface of the sliding support member  50 . Since the hanger member  17  is located in the interval between the sliding support members  50 , the base plate  10  may move rearward along the sliding support member  50  even if the hanger member  17  protrudes downward on the lower surface thereof. Since the sliding support member  50  is located in the interval between the outer frame member  18  and the base plate  10 , the outer frame member  18  is prevented from being pulled upward through the interval between the sliding support members  50 . Thus, the base plate  10  is pushed rearward in a stable state where its lower surface is in contact with the upper surface of the sliding support member  50 . 
     If the base plate  10  moves rearward, the pressing member  11  provided to the lower surface thereof is also moved rearward along with the base support plate  10  through the interval between the vertical support members  51 , namely along the guide trough  3 .  FIG. 27  shows that the pressing member  11  of the present disclosure moves rearward over the spaced distance and then the close pressing member  16  of the outer frame member  18  presses the outer circumference of the compressive deforming pipe  40  to be compressively deformed. As shown in  FIG. 27 , if the pressing member  11  passes through the spaced distance forming region L 1  and then reaches the diameter changing region L 2 , the close pressing member  16  provided to the inner surface of the outer frame member  18  starts pressing and deforming the outer circumference of the compressive deforming pipe  40 . If the pressing member  11  continues to move rearward, the close pressing member  16  continuously presses and deforms the outer circumference of the compressive deforming pipe  40  as the pressing member  11  passes through the diameter changing region L 2  and the compressive deforming region L 3 . As a result, the collision energy is dissipated. 
     As described above, the close pressing member  16  may have a semicircular pillar shape, and the convex portion a curved surface may be provided to be oriented toward the center of the perforated portion  180 . In this case, the compressive deforming pipe  40  is gradually pressed and deformed due to the curved shape of the close pressing member  16 . Accordingly, it is possible to prevent that the compressive deforming pipe  40  is rapidly crushed or the compressive deforming pipe  40  is pressed and compressively deformed in the longitudinal direction. 
     The diameter changing region L 2  having a gradually changing sectional size is present between the spaced distance forming region L 1  and the compressive deforming region L 3  of the compressive deforming pipe  40 . Thus, the compressive deforming pipe  40  is compressively deformed not suddenly but gradually. Accordingly, it is possible to prevent the collision energy from being suddenly dissipated, thereby preventing the post body  1  and the colliding vehicle from being decelerated rapidly and ensuring safe protection of the vehicle occupant more effectively. 
     In the present disclosure, no residue remains in the guide trough  3  while the compressive deforming pipe  40  serving as a collision energy absorbing member is deformed. If an obstacle is present in the guide trough  3  to disturb the rearward movement of the post body  1 , the moving speed of the post body  1  may decrease rapidly or irregularly, resulting in a significant impact on the occupant of the colliding vehicle or causing disadvantageous movement of the occupant. However, in the present disclosure, even though the compressive deforming pipe  40  is elongated in the longitudinal direction as the outer circumference thereof is pressed and deformed by the pressing member  11 , the compressive deforming pipe  40  is not crushed and does not generate residues such as fragments. Thus, there is no obstacle in the guide trough  3  that prevents the movement of the post body  1 . Thus, after the collision of the vehicle, the post body  1  moves rearward while being slowly decelerated, thereby allowing the vehicle to stop slowly and safely without exerting a significant impact on the occupant of the colliding vehicle. 
     In the configuration where the spaced distance forming region of the compressive deforming pipe  40  is divided into the front fixing end  41  and the continuous portion  42  according to the first embodiment of the present disclosure, the compressive deforming pipe  40  may be divided into the front fixing end  41  and the remainder thereof (a portion other than the front fixing end). When vehicle collision occurs, the remainder thereof other than the front fixing end  41  is compressively deformed actually. Thus, after the impact and collision energy caused by the vehicle collision is sufficiently absorbed and dissipated due to the compressive deformation of the compressive deforming pipe  40 , the front fixing end  41  and the continuous portion  42  may be separated, and then only the deformed part, namely the remainder portion other than the front fixing end may be removed and replaced with a new one and then assembled with the front fixing end  41 . After that, the post body  1  may be installed again. Thus, the crashworthy post may be restored into a reusable state quickly and easily. Since the compressive deforming pipe  40  may be reused easily and quickly by replacing only a damaged part with a new one, after a vehicle collision accident occurs, the crashworthy post may be installed again quickly at a low cost, thereby maintaining a safe road environment continuously. 
     Next, the second embodiment of the present disclosure will be described. In describing the second embodiment of the present disclosure, the same features as the first embodiment of the present disclosure will be not explained repeatedly, and different features will be explained in detail. Accordingly, in the figures depicting the second embodiment of the present disclosure, the same reference numerals are used for the same components as the first embodiment. 
       FIG. 28  is a schematic perspective view corresponding to  FIG. 11 , showing a state where the pressing member  11  is provided to the base plate  10  according to the second embodiment of the present disclosure.  FIG. 29  is a schematic front view corresponding to  FIG. 13(A) , showing the structure of  FIG. 26 . 
     In the second embodiment of the present disclosure, the base plate  10  is also integrally provided to the lower end of the post body  1 , and the pressing member  11  is integrally provided to the lower surface of the base plate  10 . In the second embodiment of the present disclosure, as shown in  FIGS. 23 and 24 , the outer frame member  18  of the pressing member  11  is directly bonded to the base plate  10  without the hanger member  17 . In the second embodiment of the present disclosure, coupling portions  12  with a “U” shape to have an interval in which the sliding support member  50  may be interposed are formed at both lateral sides of the base plate  10  to surround lateral edges of the sliding support member  50 . 
       FIG. 30  is a schematic perspective view corresponding to  FIG. 3 , showing the sliding rail assembly  5  according to the second embodiment of the present disclosure.  FIG. 31  is a schematic perspective view corresponding to  FIG. 14 , showing a state where the base plate  10  is assembled to the sliding rail assembly  5  according to the second embodiment of the present disclosure.  FIG. 32  is a schematic longitudinal sectioned view along the arrow W-W of  FIG. 31 . A pair of sliding support members  50  are provided with a lateral interval. In the second embodiment of the present disclosure, the widening cut portion is not formed at the sliding support member  50 . However, the lateral interval between the sliding support members  50  is greater than or equal to the lateral width of the outer frame member  18  attached to the base plate  10 . Thus, even in a state where the outer frame member  18  is attached to the lower surface of the base plate  10 , the base plate  10  and the pressing member  11  may pass between the sliding support members  50 . 
     In the second embodiment of the present disclosure, the coupling portions  12  are formed at both lateral sides of the base plate  10 . Thus, when the base plate  10  is placed on the sliding support member  50  and the pressing member  11  is positioned in the guide trough between two vertical support members  51 , as shown in  FIG. 32 , the sliding support member  50  is interposed in the “U” shaped interval of the coupling portion  12 . Thus, when the post body  1  is installed to stand up, the lower surface of the base plate  10  is in close contact with the upper surface of the sliding support member  50 . 
       FIG. 33  is a schematic exploded perspective view for illustrating a process of “assembling the base plate  10  and the sliding rail assembly  5 ” according to the second embodiment of the present disclosure. In  FIG. 33 , the spaced distance forming region L 1  of the compressive deforming pipe  40  is also divided into the front fixing end  41  and the continuous portion  42 . In addition, the fixing part  410  for fixing the compressive deforming pipe  40  is fixed to the ground at a front position of the bottom member  52  deviating from the bottom member  52 , and the front fixing end  41  of the compressive deforming pipe  40  is coupled thereto. In this configuration, first, the front fixing end  41  and the continuous portion  42  of the compressive deforming pipe  40  are separated, and the pressing member  11  is positioned between the front fixing end  41  and the continuous portion  42 . Subsequently, the base plate  10  is moved rearward so that the sliding support member  50  is interposed in the “U” shaped interval of the coupling portion  12 . The continuous portion  42  of the compressive deforming pipe  40  is moved forward so that the continuous portion  42  is interposed in the perforated portion  180  formed in the outer frame member  18  of the pressing member  11 . The continuous portion  42  is assembled with the front fixing end  41  again to be tightly integrated. By doing so, the base plate  10  and the sliding rail assembly  5  are reassembled. It is also possible that, after the continuous portion  42  is interposed in the perforated portion  180  of the outer frame member  18 , the base plate  10  is moved rearward so that the sliding support member  50  is interposed in the “U” shaped interval of the coupling portion  12 . The process of separating the front fixing end  41  and the continuous portion  42  of the compressive deforming pipe  40 , interposing the continuous portion  42  in the perforated portion  180  of the outer frame member  18  and then coupling the continuous portion  42  with the front fixing end  41  again for continuous operation is substantially identical to the above explanation of  FIG. 16 . 
     The second embodiment of the present disclosure may be applied even when the rear end of the compressive deforming pipe  40  (the rear end of the compressive deforming region) is coupled to the fixing part  410  as shown in  FIG. 9 .  FIG. 34  is a schematic exploded perspective view corresponding to  FIG. 33 , showing “the work for assembling the base plate  10  and the sliding rail assembly  5 ” according to the second embodiment of the present disclosure in a state where the rear end of the compressive deforming pipe  40  is coupled to the fixing part  410 . In the configuration where the rear end of the compressive deforming pipe  40  is coupled to the fixing part  410 , it is not necessary to divide the spaced distance forming region L 1  of the compressive deforming pipe  40  into the fixing end  41  and the continuous portion  42 . In addition, in order to perform “the work for assembling the base plate  10  and the sliding rail assembly  5 ”, as shown in  FIG. 34 , the base plate  10  is positioned at the foremost side of the sliding support member  50 , namely the foremost side of the sliding rail assembly, and then the base plate  10  is moved rearward so that the sliding support member  50  is interposed in the “U” shape interval of the coupling portion  12 . If the continuous portion  42  of the compressive deforming pipe  40  is moved so that the continuous portion  42  is interposed in the perforated portion  180  formed in the outer frame member  18  of the pressing member  11 , the pressing member is located in the interval between the sliding support members in a state where the compressive deforming pipe is interposed in the perforated portion  180 . When performing “the work for assembling the base plate  10  and the sliding rail assembly  5 ” as shown in  FIG. 34 , the fixing part  410  may be placed on the bottom member  52  at a rear position of the bottom member  52  and installed to be integrated with the bottom member  52 , if necessary. 
     The base plate  10  and the sliding rail assembly  5  are assembled according to the method shown in  FIG. 33  or  FIG. 34 , and the work for constructing the base member  2  and the work for assembling and the post body  1  are performed simultaneously or sequentially to completely install the crashworthy post  100 . Similar to the first embodiment described above, in the second embodiment of the present disclosure, if the vehicle collides with the post body  1 , the vehicle, the post body  1  and the base plate  10  move rearward. As the pressing member  11  moves rearward, the outer frame member  18  presses and compressively deforms the outer circumference of the compressive deforming pipe  40 . The collision energy of the vehicle is dissipated by the compressive deformation of the compressive deforming pipe  40 . In the second embodiment of the present disclosure, the base plate  10  moves rearward in a state where the coupling portion  12  having a “U” shape surrounds the lateral edges of the sliding support member  50 . Thus, the base plate  10  is pushed rearward in a stable state where its lower surface is kept in contact with the upper surface of the sliding support member  50 . As mentioned above, other configurations and effects of the second embodiment of the present disclosure are substantially identical to those of the first embodiment and thus are not described in detail again.