Abstract:
A railroad freight car adapted for carrying automobiles and having a pair of doors enclosing and end of the car body. The pair of doors is hinged to the sides of the car body and meets each other at a central vertical plane, with each door including latches at top and bottom that engage an end sill and a roof the car body. The doors include panels of composite construction and have stiffening structures along vertically extending closure mating sides of the doors, whose margins confront each other. Door engagement members on each door extend toward and are engaged with the stiffening structures on the margin of the opposite one of the pair of doors.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to railroad freight cars useful for carrying motor vehicles, and particularly to end doors for such cars, for preventing unauthorized access to motor vehicles being carried. 
         [0002]    Railroad freight cars have long been used for transporting newly manufactured motor vehicles long distances from the point of manufacture or a port of arrival to cities where dealerships are located or to railroad terminals where the motor vehicles are loaded onto trucks for transport over highways to the locations of dealerships. 
         [0003]    In order to avoid pilferage or vandalism of motor vehicles and to protect motor vehicles from airborne hazards, many railroad freight cars designed to carry motor vehicles are enclosed and include roofs and end doors. 
         [0004]    Such railroad freight cars include doors at either end of the car to prevent unauthorized access to motor vehicles carried within the car. Some such railroad freight cars include pairs of doors that are hinged at opposite sidewall corners of the car, with the doors meeting each other at the centerline of the car and being latched to the end sill and roof of the car to keep them closed. In the past, however, thieves have been known to gain access to motor vehicles carried within such cars by applying significant force to the edges of the end doors of such cars, where the doors meet each other at centerline of an end of the freight car. In response, the American Association of Railroads has established standards for the amount of force that the end doors of such a railroad freight car must successfully be able to resist. 
         [0005]    While the doors of a railroad freight car must be functional to prevent access to the cargo within an enclosed car, it is always desirable to reduce the tare weight of a car when practical, in order to avoid the expense of fuel for hauling anything other than freight-earning cargo. Railroad freight car and doors have therefore recently been built of composite materials in order to reduce the weight of those doors, with the result that some such doors are more flexible and thus more susceptible to being pulled open than were the heavier, stronger doors built in the past. 
         [0006]    What is needed, then, is a door for enclosing cargo within a railroad freight car that is not only light in weight but also resistant to being pulled open by a moderate amount of brute force. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention overcomes some of the aforementioned shortcomings of prior art railroad cars by providing a railroad freight car including a pair of end doors that provide ample resistance to being pulled open by thieves or vandals. 
         [0008]    A railroad car that is one embodiment of the invention claimed herein includes end doors of lightweight composite materials, each door including stiffening structures along the margins that meet each other at the centerline of the car. 
         [0009]    In one embodiment of the present invention, a pair of end doors includes latches to engage the car body at the top and bottom of the doorway at the end of the car, and interlocking members are mounted on a margin of each door in position to engage the margin of the adjacent door of the pair between the top and bottom latches. 
         [0010]    The foregoing and other objectives and features of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a side elevational view of a railroad freight car designed for transport of motor vehicles and having end doors at each end of the car body. 
           [0012]      FIG. 2  is an end elevational view of the railroad freight car shown in  FIG. 1 , at an enlarged scale. 
           [0013]      FIG. 3  is an elevational view of one of the doors shown in  FIG. 2 , at an enlarged scale. 
           [0014]      FIG. 4  is an elevational view of the door shown in  FIG. 3 , viewed from inside the body of the railroad freight car shown in  FIGS. 1 and 2 . 
           [0015]      FIG. 5  is an elevational view from inside the body of the railroad freight car shown in  FIGS. 1 and 2 , showing both of the end doors, with the doors closed and mated with one another. 
           [0016]      FIG. 6  is a sectional detail view taken along line  6 - 6  of  FIG. 4 . 
           [0017]      FIG. 7  is a detail view, at an enlarged scale, of a portion of  FIG. 6 . 
           [0018]      FIG. 8  is a detail sectional view taken along line  8 - 8  of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0019]    Referring first to  FIG. 1 , a railroad freight car  10  has a body  12  including a pair of opposite ends  14  and  16 . The car body  12  includes a roof  18  and an end sill  20  at each of the ends  14  and  16 . 
         [0020]    As may be seen in  FIG. 2 , a pair of doors  22  and  24  enclose the end  16  of the car body  12 , extending vertically from the roof  18  down to the end sill  20 . Each of the doors  22  and  24  includes three panels interconnected with each other by vertically extending hinges. A hinge side  26  of the door  22  and a hinge side  28  of the door  24  are mounted on respective sides of the car body  12 . A vertically extending closure mating side  30  of the door  22  confronts and extends alongside a closure mating side  32  of the door  24 . Each of the doors  22  and  24  has a respective latch  34  located at a top end of the door and engaging the door with the roof  18 . Each of the doors  22  and  24  also has a respective latch mechanism  36  at a bottom end of the door and engaging the door with the end sill  20  of the car body  12 . 
         [0021]    At least a door panel  38  of the door  22  and a door panel  40  of the door  24 , and desirably all the panels of each of the doors  22  and  24 , may be of composite material construction including a core  39  of a light, yet strong material such as balsa wood surrounded by a skin  41  of a composite material such as fiber-reinforced plastic resin. 
         [0022]    As shown in  FIG. 3  with respect to the door  24 , each of the doors  22  and  24  includes a stiffening structure extending along the margin of the respective closure mating side  30  or  32 . The stiffening structure may include an outer reinforcing plate  42  extending vertically along a margin of the closure mating side  32  on an exterior face of the door  24 , as shown in  FIG. 3 . The reinforcing plate  42  may be of a strong steel plate construction with a width  44  and may extend from a point a few inches above the bottom end of the door  24  to a point within a few inches of the top end of the door  24 , as may be seen in  FIG. 3 . 
         [0023]    The door stiffening structure may also include an inner reinforcing member  46  extending vertically along a margin of the closure mating side  32  of the door  24  on its interior side, as shown in  FIG. 4 . The inner reinforcing member  46  may have a width  48  similar to the width  44  of the reinforcing plate  42 , and also extends from within a few inches from the bottom end of the door  24  to within a few inches of the top end of the door  24 , and is aligned with and opposite the reinforcing plate  42 . The reinforcing plate  42  and the reinforcing member  46  are interconnected with each other by a plurality of fasteners  50  such as bolts or rivets extending through the panel  40 . 
         [0024]    The outer reinforcing plate  42  and inner reinforcing member  46 , separated from each other by the door panel, are spaced apart from the neutral axis of the door and absorb the highest stresses to resist bending in the door panel  38  or  40 . 
         [0025]    A pair of door engagement members  52  and  54  is carried on the interior of the door  24  along the closure mating side  32  and may be welded to the top of the “hat” shape of the reinforcing member  46 . Each door engagement member has a relatively wide base and is tapered to a relatively narrow outer end, so the wide base can carry any stresses to a larger area of the inner reinforcing member  46 . 
         [0026]    Retainer pins  56  and  58  are located at the top end and bottom end, respectively, of the closure mating side  32  of the door  24  and are captured by respective hooks on the roof  18  and the end sill  20  as the door  24  is moved through the last few inches before it is completely closed toward the door  22  and the centerline of the car  10 . Thus, when the door  24  is fully closed, the retainer pins  56  and  58  hold the closure mating side  32  of the door  24  in its required position, close to the roof  18  and the end sill  20  for complete closure of the end  16  of the car body  12 , and the door stiffening structure maintains a rigid and straight, or planar configuration of the door to resist an attempt by a would-be unauthorized entrant. 
         [0027]    A similar stiffening structure is also provided on the opposite side door  22 , as shown in  FIG. 5 , where it may also be seen that the door  22  includes an upper door engagement member  60  and a lower door engagement member  62  similar to the door engagement members  52  and  54  on the door  24 . The door engagement members  60  and  62  are mounted on the door  22  at respective heights slightly lower than the adjacent door engagement members  52  and  54  on the door  24 , so that the doors  22  and  24  may be closed fully without the door engagement members interfering with each other. The door  22  also includes retainer pins  56  and  58 , as shown in  FIG. 5 . 
         [0028]    As shown best in  FIGS. 6 and 7 , each of the door engagement members  52 ,  54 ,  60 , and  62  is attached to a respective one of the reinforcing members  42 , as, for example, by being welded to the channel base, the top of the “top hat” shape. Additionally another attachment member  64  of sheet metal similar to or a part of the inner reinforcing member  46  may extend away from the door panel  38  or  40  to interconnect the respective door engagement member with the inner reinforcing member  46 , as seen best in  FIG. 7 . An outer end  66  portion of each door engagement member  52 ,  54 ,  60 , and  62  extends beyond the margin of the respective closure mating side  30  or  32 , away from the respective hinge side  26  or  28  of the door on which the engagement member is mounted. 
         [0029]    Each door engagement member  52 ,  54 ,  60 , and  62  is spaced away from the door panel  40  to which it is connected by its location on the reinforcing hat shaped channel member  46 , facilitating engaging the margin of the closure mating side of the opposite door as the doors  22  and  24  are moved to close them, but as shown in  FIG. 8 , each door engagement member overlaps the margin of the opposite door  22  or  24 , so that the door engagement members prevent either door from being moved outward relative to the other by a distance greater than the height of the hat shape of the members  46 . In  FIG. 8  adjacent opposing portions of the two doors  22  and  24  are illustrated with both of the doors  22  and  24  are in their fully closed positions with their respective closure mating sides  30  and  32  confronting each other. 
         [0030]    On each of the doors  22  and  24 , the respective ones of its pair of door engagement members  52 ,  54 , or  60 ,  62  are separated by a distance  72 , center-to-center, in the range of about one-fifth to about one-third of the total height of the door. The lower door engagement member  54  or  62  of each door may be spaced apart from the bottom of the respective door by a somewhat greater distance  76 , in the range of about 35% to about 45% of the entire height of the door. Each of the upper ones of the door engagement members  52  and  60  may be separated from the top of the respective door by a distance  76  that may be in the range of about 35% to about 40% of the entire height of the door. 
         [0031]    The engagement of the pins  56  with hooks at the roof  18 , engagement of the pins  58  with hooks on the end sill of the car body, the stiffening structures including outer reinforcing plates  42  and inner reinforcing members  46 , and the door engagement members  52 ,  54 ,  60 , and  62  that prevent the margins of the closure mating sides  30  and  32  of the doors from being moved past each other, provide a stiffened door construction capable of successfully resisting nearly any attempt at unauthorized entry into such a railroad freight car  10 . 
         [0032]    The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.