Abstract:
The invention provides a small-sized, light weight and low cost obstacle deflector for removing obstacles on a railway track. An obstacle deflector  30  is composed, from the front side in the running direction of the car body, of an obstacle deflection member  31  and a connecting mechanism  40 , wherein the connecting mechanism  40  is composed of two connecting units disposed parallel to one another, each composed of a distribution member  33 , a support member  47 , an energy absorber  35  and a rod  37 . The obstacle deflection member  31  is disposed along the width direction of the car body and connected rotatably via a first pin  32 . The center portion in the width direction of the obstacle deflection member  31  is connected via a pin  34  to the distribution member  33 , and further via support members  47  to energy absorbers  35  for absorbing impact load. The energy absorbers  35  are connected via rods  37  and second pins  38  to the lower surface  3   b  of an underframe. Regardless of where in the width direction the obstacles collide against the obstacle deflection member  31 , the impact load is transmitted uniformly via the distribution member  33  to the energy absorbers  35  and  35.

Description:
[0001]    The present application is based on and claims priority of Japanese patent application No. 2007-187504 filed on Jul. 18, 2007, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an obstacle deflector for eliminating obstacles on railway tracks which is disposed on railway cars such as railroad vehicles, streetcars, electric trains of new urban traffic systems and monorail cars, and railway cars equipped with such obstacle deflector. 
         [0004]    2. Description of the Related Art 
         [0005]    Japanese Patent Laid-Open Publications No. 2005-206006 (patent document 1), No. 2001-55141 (patent document 2) and No. 2003-137094 (patent document 3) disclose structures for eliminating obstacles on railway tracks. Patent documents 1 through 3 disclose an obstacle deflector disposed on a car body at a leading end portion of the railway car and positioned above the railway track for eliminating obstacles on the railway track. 
         [0006]    The obstacle deflector disclosed in the above patent documents is a U-shaped member when viewed from above, wherein the U-shaped member is connected at multiple locations on a lower surface of an underframe. Further, the U-shaped member is connected at its rear portion with the underframe. The U-shaped member can also be V-shaped. 
         [0007]    The obstacle deflector has an energy absorber disposed at a rear position on a rear surface at the center of the width-direction of the U-shaped member. When the U-shaped member collides against an obstacle, the energy absorber collapses in a bellows, absorbing the collision energy. 
         [0008]    In the structure disclosed in patent documents 1 through 3, a U-shaped member is disposed on a lower surface of the underframe, and the U-shaped member is attached at plural locations on the underframe. Therefore, the U-shaped member is large-sized, and since the U-shaped member must be attached at plural locations on the lower surface of the underframe, the attaching operation becomes difficult. 
       SUMMARY OF THE INVENTION 
       [0009]    The object of the present invention is to provide an obstacle deflector that has minimum influence on the underframe and car body when colliding against an obstacle, which is small-sized and can be disposed easily. 
         [0010]    The above object is realized by a railway car having an obstacle deflector disposed on a lower surface of an underframe of the railway car, wherein the obstacle deflector is supported on the lower surface of the underframe at two locations spaced apart from one another in a running direction of the railway car when seen from a side direction with respect to the running direction; the obstacle deflector comprises an obstacle deflection member that collides against an obstacle, a first pin positioned at one of the two locations and rotatably connecting the obstacle deflection member to the lower surface of the underframe, a connecting mechanism for connecting the obstacle deflection member and the underframe, a second pin positioned at the other one of the two locations and rotatably connecting the connecting mechanism to the lower surface of the underframe, and a third pin for connecting the obstacle deflection member and the connecting mechanism; and the first pin and the second pin has axles oriented horizontally in a width direction with respect to the running direction of the railway car. 
         [0011]    Moreover, the above object is realized by an obstacle deflector disposed on a lower surface of an underframe of the railway car, wherein the obstacle deflector is supported on the lower surface of the underframe at two locations spaced apart from one another in a running direction of the railway car when viewed in a side direction with respect to the running direction; the obstacle deflector comprises an obstacle deflection member that collides against an obstacle, a first pin positioned at one of the two locations and rotatably connecting the obstacle deflection member to the lower surface of the underframe, a connecting mechanism for connecting the obstacle deflection member and the underframe, a second pin positioned at the other one of the two locations and rotatably connecting the connecting mechanism to the lower surface of the underframe, and a third pin for connecting the obstacle deflection member and the connecting mechanism; and the first pin and the second pin has axles oriented horizontally in a width direction with respect to the running direction of the railway car. 
         [0012]    According to the railway car having the arrangement described above and the obstacle deflector to be attached to the railway car, the impact load generated by an obstacle colliding against the obstacle deflection member is transmitted via the connecting mechanism to the underframe. Since the obstacle deflection member and the connecting mechanism is respectively connected via pins to the underframe, they constitute a link mechanism, according to which the underframe receives the given impact load as a simple axial force, and no flexural load is applied to the underframe. Thus, since, there is no need for a guide mechanism for slidably supporting the connecting mechanism according to the present invention, the structures of the obstacle deflector and the railway car are simplified, the effect of the impact load to the underframe or the car body is simplified, and so the structure is advantageous. 
         [0013]    Further according to the present invention, when the connecting mechanism is equipped with a distribution member and an energy absorber, the energy absorber absorbs the collision energy generated by the collision of an obstacle against the obstacle deflection member, and reduces the impact load transmitted to the underframe. Moreover, when a relatively small load is applied on the obstacle deflection member, the energy absorber will not activate, but when a large load is applied, the energy absorber collapses in a bellows and absorbs the collision energy. Since the whole body of the energy absorber receives axial force only and does not receive bending moment, the energy absorber is crushed effectively and exerts maximum energy absorbing function. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view showing one embodiment of a railway car with an obstacle deflector according to the present invention; 
           [0015]      FIG. 2  is a side view of the obstacle deflector illustrated in  FIG. 1 ; 
           [0016]      FIG. 3  is a cross-sectional view taken at line III-III of  FIG. 2 ; 
           [0017]      FIG. 4  is an enlarged plan view of portion IV of  FIG. 3 ; 
           [0018]      FIG. 5  is a cross-sectional view taken at line V-V of  FIG. 4 ; 
           [0019]      FIG. 6  is a cross-sectional view taken at line VI-VI of  FIG. 5 ; 
           [0020]      FIG. 7A  is an explanatory view of the load and reaction force applied to the obstacle deflector according to the present invention, and  FIG. 7B  is an explanatory view of the same according to a prior art example; 
           [0021]      FIG. 8  is a view corresponding to  FIG. 3  showing another embodiment of the present invention; and 
           [0022]      FIG. 9  is a view corresponding to  FIG. 6  showing yet another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The preferred embodiments of a railway car according to the present invention will be described with reference to the drawings. 
       Embodiment 1 
       [0024]    One preferred embodiment of the present invention will be described with reference to  FIGS. 1 through 7 . In  FIG. 1 , the railway car body structure  5  is composed of a roof structure  1  constituting an upper plane thereof, two side structures  2  and  2  constituting side walls thereof, an underframe  3  constituting a lower plane thereof, and two end structures  4  and  4  closing the longitudinal end faces of the car. The roof structure  1 , the side structures  2  and  2 , the underframe  3  and the end structures  4  and  4  are each composed by welding a plurality of extruded shape members. The extruded shape members constituting the roof structure  1 , the side structures  2  and  2  and the underframe  3  are hollow shape members made of aluminum alloy, and the direction of extrusion thereof corresponds to the front rear direction of the railway car body structure  5 . The extruded shape members constituting the end structures  4  and  4  are shape members with ribs formed of aluminum alloy, and the direction of extrusion thereof corresponds to the vertical direction of the railway car body structure  5 . On the lower surface of an underframe  3  at the front portion in the longitudinal direction of the railway car body structure  5  is disposed an obstacle deflector  30  positioned toward the longitudinal direction. 
         [0025]    The obstacle deflector  30  is disposed on the lower surface  3   b  of the underframe of the car body. In  FIG. 2 , the front end portion of the obstacle deflector  30  is disposed as close to the front end portion of the car body as possible. An obstacle deflection member  31  at the front end portion is a high-strength member composed of a thick plate made of iron. The upper end portion of the obstacle deflection member  31  is suspended from the underframe  3  or a mounting hardware attached to the lower surface  3  of the underframe via pins  32  and  32 . The pins  32  are arranged so that their axial direction corresponds to the width direction of the car body. The obstacle deflection member  31  extends along the width direction of the car body. The obstacle deflection member  31  is slanted so that when viewed from above, the front side is reduced in size from the center of the width direction toward the width-direction-ends. What is meant by the description that the obstacle deflection member is slanted so that its front side is “reduced in size” is that when the obstacle deflection member  31  is viewed from above, the member is pentagon-shaped with the center portion having the most thickness and its thickness being reduced gradually toward the ends. 
         [0026]    When an obstacle collides against the obstacle deflection member  31 , the obstacle deflection member  31  receives force in a direction to rotate the lower end of the obstacle deflection member  31  toward the rear direction around pins  32 . There are two pins  32  disposed along the width direction of the obstacle deflection member. 
         [0027]    Further, the obstacle deflector  30  comprises a connecting mechanism  40  including a distribution member  33  disposed parallel to the obstacle deflection member  31 , two support members  47  and  47  attached to the distribution member  33 , energy absorbers  35  and  35  connected via load transmitting shafts  44  and  44  to the support members  47  and  47 , two rods  37  and  37  connected to the energy absorbers  35  and  35 , and pins  38  and  38  connecting the rods  37  and  37  to the lower surface  3   b  of the underframe. The distribution member  33  is a high-strength member made of iron. The two sets of components each composed of the support member  47 , the load transmitting shaft  44 , the energy absorber  35  and the rod  37  disposed rearward from the distribution member  33  each constitute a parallel connecting unit. 
         [0028]    What is meant by the term “parallel” is that the distribution member  33  is disposed in the width direction, similar to the obstacle deflection member  31 . 
         [0029]    The energy absorber  35  collapses and absorbs the collision energy when collision with an obstacle occurs. 
         [0030]    The pin  32  is disposed at two longitudinal locations on an upper end of the obstacle deflection member  31  along the width direction. The axial direction of each pin  31  corresponds to the width direction. 
         [0031]    The obstacle deflection member  31  and the distribution member  33  are connected via a single pin  34 . The pin  34  is disposed at the center of the width direction between the obstacle deflection member  31  and the distribution member  33 . The axial direction of the pin  34  corresponds to the width direction in  FIG. 2 , but it can also be disposed in the perpendicular direction. 
         [0032]    The rods  37  and  37  are disposed on the lower surface  3   b  of the underframe via pins  38  and  38 . The rods  37  and  37  are connected ratatably in vertical direction via pins  38  and  38 . Thus, the obstacle deflector  30  realizes a link structure which is attached via pins  32  and  38  on the lower surface  3   b  of the underframe when viewed from the side direction with respect to the running direction of the vehicle. 
         [0033]    The support members  47  and  47  (and energy absorbers  35  and  35  connected thereto) are connected to the distribution member  33  at equal distanced positions in the width direction from the pin  34 . 
         [0034]    The point of connection between the rods  37  and  37  and the lower surface  3   b  of the underframe (the horizontal and height positions of the pins  38  and  38 ) can be anywhere, but it is preferable that the pins  38  are positioned at corresponding positions and as distanced from the obstacle deflection member  31  as possible. This is preferable since when the obstacle deflection member  31  collides against an obstacle, the direction of impact force conducted via rods  37  and  37  to the underframe should be as close to the plane of the underframe as possible to reduce upthrust force. The rods  37  are crossed perpendicularly with axles  39  at positions above the axles  39  supporting the car body on the rails. The rods  37  are arranged to extend above the axles  39  with a distance therebetween preventing the rods  37  from coming into contact with the axles  39  even when air cushions (not shown) blow out. 
         [0035]    The lower end of the obstacle deflection member  31  is positioned on an extended line of the connecting line connecting the pin  34  and the pin  38 . If the extended line is positioned above the lower end of the obstacle deflection member  31 , the load acting on the energy absorbers  35  becomes excessive considering the balance of load acting on the obstacle deflection member  31  at the time of collision with an obstacle, which is not preferable. Further, if the extended line is positioned below the lower end, the clearance between the distribution member  33  and the rail surface becomes excessively small and is not desirable, since the lower end of the obstacle deflection member  31  is positioned as close to the rail surface as possible. In this sense, it is preferable that the lower end of the obstacle deflection member is disposed on the above-mentioned extended line. Even though it is described that the obstacle deflection member  31  is positioned “on the extended line”, a small variation in the vertical direction is permissible. 
         [0036]    The energy absorbers  35  can adopt any structure, as long as they are capable of absorbing collision energy. One preferable example is an extruded shape member made of aluminum alloy, which collapses in a bellows with respect to the running direction when receiving impact load to absorb the collision energy. 
         [0037]    In  FIG. 6 , the energy absorber  35  is a hollow extruded shape member having an octagonal cross-section formed of a material having superior shock absorbing property, such as an A6063S-T5. The direction of extrusion of the hollow extruded shape member corresponds to the direction of operation of the impact load. 
         [0038]    The direction of operation of the impact load, that is, the running direction, is from left to right in the drawing of  FIG. 5 . A hole  35   d  is formed to pass through in the direction of operation of the impact load at the center of the octagonal cross-section. The energy absorber  35  has its front end covered with a closing plate  42 , its rear end covered with a closing plate  43 , and attached to the front and rear closing plates  42  and  43 . A hole  35   d  is formed at the center of the closing plates  42  and  43  and the energy absorber  35 , and a load transmitting shaft  44  is passed through the inner side of closing plates  42  and  43  and the hole  35   d . The load transmitting shaft  44  has a circular cross-section. The term “front end” refers to the left side of  FIG. 5 , and the term “rear end” refers to the right side of  FIG. 5 . In  FIG. 6 , the load transmitting shaft  44  is not shown. 
         [0039]    The energy absorber  35  is composed of an inner cylinder  35   a  having an octagonal cross-section disposed at the inner side, an outer cylinder  35   b  having an octagonal cross-section disposed at the outer side, and a plurality of connecting plates  35   c  connecting the inner and outer cylinders. The connecting plates  35   c  are attached to intersecting points of the octagons in the form of a truss. 
         [0040]    The closing plate  42  disposed at the front end of the energy absorber  35  is opposed to the rear end of the supporting member  47  via a gap G of 8.5 mm, for example. The closing plate  43  at the rear end of the energy absorber  35  is engaged via bolts and nuts  46  to the rod  37 . The load transmitting shaft  44  attached to the front end of the rod  37  is connected via a pin  48  to the supporting member  47  at the front end portion penetrated through the hole  35   d  and protruded from the closing plate  42 . 
         [0041]    The pin  48  is passed through a hole  44   c  formed to the load transmitting rod  44  and the hole  47   c  formed to the supporting member  47 . Notched grooves  48   c  are formed to the outer surface of the pin  48  between the side surface of the load transmitting shaft  44  facing the outer side of the width direction of the car body and the side surface of the supporting member  47  facing the inner side of the width direction of the car body, and the notched grooves  48   c  enable the pin  48  to break easily by impact load. In other words, the notched grooves  48   c  formed on the outer circumference of the pin  48  between the load transmitting shaft  44  and the supporting member  47  are formed so as to enable the pin to break easily when impact load is applied to the support member  47 , enabling the supporting member  47  to collide against the closing plate  42  by the impact load. A hole  33   b  is formed on the opposing side of the distribution member  33  to allow the load transmitting shaft  44  to pass therethrough when the pin  48  breaks when the distance between the front end of the load transmitting shaft  44  and the rear end of the distribution member  33  is short. 
         [0042]    The support members  47  and  47  are attached to the distribution member  33 . Each support member  47  has a substantially same outer shape as the energy absorber  35 . That is, the energy absorber  35  has an octagonal cross-section, and the support member  47  also has an octagonal cross-section. If the support member  47  is a hollow shape member, a closing plate (not shown) is attached to the rear end thereof. 
         [0043]    As described, the rear end of the support member  47  is opposed via a gap G to a closing plate  42 . According to such structure, the function of the energy absorber  35  can be turned on and off according to the level of impact load. 
         [0044]    In other words, when a small load is applied on the obstacle deflection member  31 , the front end of the energy absorber  35  is opposed to the support member  47  with a gap G therebetween, so the impact load is not applied on the energy absorber  35 . This state is referred to as “off”. 
         [0045]    On the other hand, when a large load is applied on the obstacle deflection member  31 , the impact load is applied via the obstacle deflection member  31 , the pin  34 , the distribution member  33  and the support members  47  to pins  48  and load transmitting shafts  44 . Thereby, the pins  48  break and the support members  47  collide against the energy absorbers  35 . This state in which the pins  48  are broken is referred to as “on”. In other words, the rear end portion of the support members  47  collide against the closing plates  42 , by which the impact load is transmitted to the energy absorbers  35 , making the energy absorbers  35  collapse in a bellows with respect to the direction of operation of the impact load. The collision energy is absorbed by this collapse. 
         [0046]    As described, since the operation of impact load to the energy absorbers  35  is turned on and off, it becomes possible to prevent replacement of the energy absorbers  35  when only a small load is applied thereto, and to prevent the occurrence of lack of function of the energy absorbers  35  when a large load is applied thereto. 
         [0047]    Furthermore, the obstacle deflection member  31 , the rods  37  and the underframe  3  are respectively connected via pins  32  and  38 , by which a link mechanism is composed. Thus, even when an obstacle collides against the obstacle deflection member  31 , only a load in the axial direction (substantially a compressive load) connecting the pin  34  and the pin  38  in  FIG. 2  is applied to the connecting mechanism  40  composed of the distribution member  33 , the support members  47 , the load transmitting shafts  44 , the energy absorbers  35  and the rods  37  connecting the pin  34  and the pins  38 , and no flexural load (moment) is applied. Therefore, no flexural load is applied to the underframe  3  via the rods  37 . Thus, only a simple tensile and compressive load is applied to the underframe  3 , and so there is no need to enhance the strength excessively. 
         [0048]    Furthermore, the above-described link mechanism enables only simple compressive load to be applied to the energy absorbers  35 , so the energy absorbers  35  can be collapsed in a straight direction without fail to absorb the collision energy efficiently. Thus, there is no need to add any extra structure such as a guide mechanism for guiding the energy absorbers  35  to be collapsed in a straight direction. In replacement of the link mechanism, it is possible to arrange energy absorbers  35  horizontally between the obstacle deflection member  31  and the underframe  3 , but in order to enable the energy absorbers  35  to be collapsed in the correct horizontal direction, a guide mechanism must be provided between the underframe  3  to enable the energy absorbers  35  to slide in the horizontal direction. As described in the present embodiment, the guide mechanism is no longer necessary when a link mechanism using pins  32 ,  34  and  38  is adopted, and the structure of the obstacle deflector can be simplified. 
         [0049]    Furthermore, the distribution member  33  and the obstacle deflection member  31  are connected at the center portion in the width direction via a pin  34 . Moreover, since the energy absorbers  35  and  35  are attached to the distribution member  33  at equal distances from the pin  34 , load is applied uniformly to the absorbers  35  and  35  and rods  37  and  37 . Thereby, regardless of the width-direction position in which the obstacle collides against the obstacle deflection member  31 , the impact load is transmitted via the pin  34  to the distribution member  33 , and load is transmitted uniformly to the energy absorbers  35  and  35  positioned at equal distances from the pin  34 . 
         [0050]    This is described in further detail with reference to  FIG. 7 .  FIG. 7  illustrates the impact load F applied to the obstacle deflector and the reaction force thereof.  FIG. 7A  is an explanatory view showing the load and the reaction force corresponding to  FIG. 3  of the present invention.  FIG. 7B  is an explanatory view showing an assumed prior art example. 
         [0051]      FIG. 7A  illustrates a case in which an obstacle collides against one end of the obstacle deflection member  31 . The impact load F applied to the obstacle deflection member  31  is applied via the distribution member  33  to the energy absorbers  35 . Since the impact load F applied to the obstacle deflection member  31  is applied to the distribution member  33  via the pin  34 , the impact load F is applied as it is to the distribution member  33  regardless of where in the width direction the obstacle collides against the obstacle deflection member  31 , and the distance from where the obstacle collides to the pin  34  is not relevant. Further, the distances from the pin  34  to the absorbers  35  and  35  (that is, to the connecting points between the distribution member  33  and the support members  47  and  47 ) are equal. Therefore, the reaction force caused to each absorber is one-half the impact load F. 
         [0052]      FIG. 7B  illustrates a case in which the support members  47  are directly connected to the obstacle deflection member  31  (or a case in which the obstacle deflection member  31  and the distribution member  33  are connected via multiple pins). When an obstacle collides against one end of the obstacle deflection member  31 , a reaction force in the direction opposite to the impact load is generated to one of the two support members  47  and  47  (or one of the two energy absorbers  35  and  35 ) disposed closer to where the collision with the obstacle occurred, and according to the principle of leverage, a reaction force r in the same direction as the impact load F occurs to the other support member  47  (the other energy absorber  35 ). As a result, a reaction force of F+r is generated to the support member  47  (energy absorber  35 ) closer to where the obstacle collided, and the load applied to the support member  47 , the energy absorber  35 , the rod  37  and the underframe  3  is increased. 
         [0053]    According to the present invention (having the structure illustrated in  FIG. 7A ), no such phenomenon as illustrated in  FIG. 7B  occurs in which great reaction force is applied to the support member  47  closer to the point of collision, and so the two energy absorbers  35  and  35  can absorb impact load uniformly, thereby the overall structure can be reduced in size. Further, the load applied to the car body can be minimized. 
         [0054]    Moreover, according to the present structure, even when a large load is applied, the obstacle deflector  30  can be replaced with a new one by replacing the energy absorbers  35 , the bolts and nuts  46  and the pins  48 . 
         [0055]    Moreover, it is also possible to adopt a structure in which the support members  47  also collapse to absorb the collision energy when a large load is applied. 
       Embodiment 2 
       [0056]    According to embodiment 1 illustrated in  FIG. 3  described above, the pin  34  connecting the obstacle deflection member  31  and the distribution member  33  is arranged so that its axial direction is disposed in the horizontal direction, but in embodiment 2, the pin  34  is arranged in the perpendicular direction, as illustrated in  FIG. 8 . 
         [0057]    When the pin  34  is arranged perpendicularly, there is a risk that when the energy absorbers  35  collapse, the absorbers are deformed in an upward curved state, by which the energy absorption efficiency is deteriorated. However, by arranging the pin  34  in the perpendicular direction, the impact load can be distributed more uniformly in the left and right directions, that is, to the two energy absorbers  35  and  35 , compared to the case of embodiment 1. 
       Embodiment 3 
       [0058]    According to embodiment 1, each energy absorber  35  is composed of a hollow shape member having an octagonal cross-sectional shape, but as illustrated in  FIG. 9 , it can also be composed of two flat hollow shape members  35 A and  35 A and two connecting plates  35 B and  35 B connecting the width-direction ends of the hollow shape members  35 A and  35 A. The connecting plate  35 B is connected to the end portion of the hollow shape member  35 A. The space between the upper hollow shape member  35 A and the lower hollow shape member  35 A is for arranging the load transmitting shaft  44 . 
         [0059]    Though the width direction of the hollow shape member  35 A is arranged horizontally, it can also be arranged perpendicularly. Further, the member does not necessarily have to be hollow.