Abstract:
A mounting system is provided for securing a metal support surface to a metal bracket on a railroad car. The invention is improved by a compressible, energy absorbing arrangement secured intermediate the support surface and the bracket for preventing metal to metal contact between the support surface and the bracket and absorbing vibrational energy caused by movement of the railroad car.

Description:
CROSS REFERENCES TO RELATED APPLICATION  
       [0001]     This application relates to and claims priority from Provisional U.S. Patent Application Ser. No. 60/491,410 filed Jul. 31, 2003. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to the attaching of support surfaces on railroad cars and, more particularly, pertains to a fastening system used for mounting railroad car steps and running boards to a railroad car.  
       BACKGROUND OF THE INVENTION  
       [0003]     Railroad cars are typically provided with support surfaces, such as various steps and running boards, to enable personnel to access different areas onboard. Currently, these steps and running boards are manufactured from metal and are mounted by simple nut and bolt fasteners to metal brackets fixedly attached to surfaces of the railroad cars. A problem with metal to metal contact arises as the railroad cars travel along the rails creating twisting, torquing and excess harmonic vibration. These forces seriously fatigue the metal components and lead to cracking thus shortening the life of the steps and the running boards.  
         [0004]     Accordingly, it is desirable to alleviate the deficiencies of the prior art support surface attachment on railroad cars, and provide a mounting system which protects steps and running boards from the destructive vibrational energy caused by movement of the cars.  
       SUMMARY OF THE INVENTION  
       [0005]     It is a general object of the present invention to provide a system for mounting steps or running boards on a railroad car in a manner that avoids, or minimizes, fatigue and cracking.  
         [0006]     It is also an object of the present invention to provide a mounting system that greatly reduces the vibrational forces transmitted to steps and running boards attached to railroad cars.  
         [0007]     It is another object of the present invention to provide a mounting system employing an energy-absorbing, compressible bushing interposed between a step or running board and a railroad car.  
         [0008]     It is an additional object of the present invention to provide a mounting system capable of being interchanged for existing fastening systems between a railroad car support surface and a bracket on the railroad car.  
         [0009]     It is a further object of the present invention to provide a step or running board mounting system for a railroad car in which no metal fastener is in direct contact with the metal of the step or running board.  
         [0010]     In one aspect of the invention, a mounting system is provided for securing a metal to metal contact between the support surface and the bracket and absorbing vibrational energy caused by movement of the railroad car. The arrangement includes a bushing having an upstanding neck protruding through a hole formed in the support surface, and a bottom surface having an enlarged central opening provided therein. The enlarged central opening is in communication with a throughbore passing through the neck of the bushing. The arrangement further includes an insert having an expanded head with an internally threaded bore, and a threaded shaft depending from the head. The expanded head of the insert is fixedly received in the enlarged central opening in the bottom surface of the bushing. The threaded shaft of the insert extends through an opening formed in the bracket, and is engaged with a nut acting against an underside of the bracket. A cap washer is disposed upon the neck of the bushing, the cap washer having an aperture aligned with the throughbore in the neck of the bushing. A bolt has a head and a threaded shaft depending from the head and extends through the aligned aperture in the cap washer and the throughbore in the neck of the bushing. The cap washer lies between the head of the bolt and the support surface. A lower surface of the cap washer is held spaced from the support surface. The threaded shaft of the bolt is received in the internally threaded bore of the insert such that tightening of the bolt will compress the bushing beneath the cap washer so as to isolate the support surface from torque, twist and vibration. In the preferred embodiment, the support surface is a running board, and the bushing is constructed of a plastic material.  
         [0011]     In another aspect of the invention, a mounting system is provided for securing a support surface to a bracket on the railroad car. The mounting system includes a bushing disposed between the support surface and the bracket. The bushing has an upper portion protruding through a hole in the support surface, and a lower portion carrying an insert retained in the bracket. A bolt has a head positioned above the upper portion of the bushing, and a threaded shaft which passes through the bushing and is threadably received in an internally threaded bore of the insert. The bushing is constructed of an energy absorbing, compressible material. The mounting system includes a cap washer disposed upon the neck of the bushing beneath the head of the bolt in spaced relationship from the support surface. The insert has an expanded head and a threaded shaft depending from the head. The expanded head is fixedly received in an enlarged central opening formed in the lower portion of the bushing. The threaded shaft of the insert extends through an opening formed in the bracket and is engaged with a nut acting against an underside of the bracket. The bracket has an inverted, U-shape provided with a raised surface and a pair of downwardly depending legs fastened to the railroad car. A bottom surface of the bushing is supported upon the raised surface of the bracket.  
         [0012]     Various other objects, features and advantages of the invention will be made apparent from the following description taken together with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The drawings illustrate the best mode presently contemplated of carrying out the invention.  
         [0014]     In the drawings:  
         [0015]      FIG. 1  is a partial perspective view of the top of a railroad car employing a prior art mounting system for fastening a running board;  
         [0016]      FIG. 2  is a sectional view of the prior art mounting system shown in  FIG. 1 ;  
         [0017]      FIG. 3  is an exploded, front view of the isolation mounting system of the present invention.  
         [0018]      FIG. 4  is a side view of the mounting system shown in  FIG. 3 ;  
         [0019]      FIG. 5  is an assembled view of the mounting system with a partial cutaway view;  
         [0020]      FIG. 6  is a magnified detailed view of  FIG. 5 ;  
         [0021]      FIG. 7  is a sectional view showing the assembled mounting system of  FIG. 5  on opposite ends of a running board;  
         [0022]      FIG. 8   a  is a top view of a bushing employed in the mounting system of the present invention;  
         [0023]      FIG. 8   b  is a front view of the bushing shown in  FIG. 8   a;    
         [0024]      FIG. 8   c  is a bottom view of the bushing shown in  FIG. 8   a;    
         [0025]      FIG. 9   a  is a top view of a cap washer employed in the mounting system of the present invention;  
         [0026]      FIG. 9   b  is a front view of the cap washer shown in  FIG. 9   a;    
         [0027]      FIG. 10   a  is a front view of an insert employed in the mounting system of the present invention; and  
         [0028]      FIG. 10   b  is a top view of the insert shown in  FIG. 10   a.   
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
     Prior Art Mounting System  
       [0029]     Referring first to  FIG. 1 , the top of a railroad car  10  has a pair of perforated metal running boards  12  which run longitudinally on either side of a central bank of pivotable hatch covers  14  used to provide access to the interior of the car  10 . The running boards  12  act as support surfaces for operating and service personnel as they open and close the covers  14 . The sides of each running board  12  are rigidly fastened to a series of inverted, U-shaped brackets  16  that are welded to the top of the car  10 . As seen in  FIG. 2 , bolts  18  pass through aligned holes in laterally extending flanges  20  of each running board  12  and raised, upper surfaces  22  of brackets  16  with a nut  24  being applied to a threaded portion of each bolt  18  adjacent the underside of each bracket upper surface  22 . The bolt  18  and the nut  24  are in direct contact with the running board  12  and the bracket  16 . As more fully discussed in the Background of the Invention, such prior art mounting systems contribute to premature failure of the support surfaces  12  by transmitting unwanted vibrational forces which cause fatigue and cracking.  
       The Present Invention  
       [0030]     Referring now to  FIG. 3 , thereshown is a mounting system  26  of the present invention. The mounting system  26  is particularly useful in mounting the support surface or railroad car running board  12  to the bracket  16  of the railroad car  10 . As illustrated in  FIG. 3 , a generally cylindrical bushing  28  is positioned between the running board  12  and the bracket  16 . Specifically, a bottom surface  30  of the bushing  28  contacts the upper surface  22  of the bracket  16 . A bushing neck  32  extends upwardly from the bushing  28  and protrudes through a mounting hole  34  formed in the running board  12 . Preferably, the bushing  28  is formed from a compressible material such as polyurethane or another suitable plastic.  
         [0031]     The bottom surface  30  of the bushing  28  includes an enlarged central opening  36  which is in communication with a throughbore  37  passing through neck  32 , as shown in  FIGS. 5 and 8   c . The opening  36  is sized to receive an expanded head  38  of a metal insert  40  having a threaded shaft  42  as best shown in  FIGS. 3, 5  and  6 . The bottom surface  30  of the bushing  28  also is formed with a series of cavities  44  which surround central opening  36 .  
         [0032]     A metal bolt  46  extends through the throughbore  37  in the bushing  28  such that a threaded shaft  48  of the bolt  46  is received within an internally threaded bore  49  of the expanded head  38  of the insert  40 , as shown in  FIGS. 5, 10   a  and  10   b . Referring to  FIG. 5 , the bolt  46  also passes through an aperture  50  in an engineered metal cap washer  51  which rests upon the bushing neck  32  and is entrapped between a head  52  of the bolt  46  and an extruded upper lip  54  of the running board  12 . The cap washer  51  is formed with a downwardly and outwardly sloping side wall  53  as best seen in  FIG. 9   b . The threaded interaction between the bolt  46  and the head  38  of the insert  40  compresses the bushing  28  beneath the cap washer  51 . Referring now to  FIG. 5 , as the bolt  46  is tightened, the cap washer  51  compresses the neck  32  of the bushing  28  to create a snug fit between the bushing  28  and the running board  12 . The compression of the neck  32  can also clearly be seen in  FIG. 6 .  
         [0033]     The amount of compression of the bushing neck  32  is controlled by the tightening of the bolt  46  into the head  38  of the insert  40 . It is contemplated that the length of the threaded shaft  48  will be set to control the amount of compression of the neck  32 .  
         [0034]     The insert  40 , in turn, includes the shaft  42  that extends through an opening  56  formed in the bracket  16 , and is received by a metal nut  58 . The nut  58  holds the insert  40  in place relative to the bracket  16 .  
         [0035]     As shown in  FIGS. 10   a  and  10   b , the expanded head  38  includes a series of outer ridges  60 . The outer ridges  60  function to prevent rotation of the head  38  within the bushing  28  when it is mounted as shown in  FIG. 5 .  
         [0036]      FIGS. 5 and 6  show detailed views of the mounting system  26  of the present invention, where reference numerals are similar to those used in  FIGS. 3 and 4 . As can be understood in the drawings, the bushing  28  is designed with a specific hardness that, under compression, isolates the running board  12  from the torque, twist and harmonic vibrations as the railroad car  10  travels along the rail. Further, in contrast with the prior art, metal fastener  46  and washer  51  are not in contact with the metal of the running board  12 . Thus, the running board  12  is free of flex, which ultimately fatigues metal and causes cracking, such that movement of the car mounts transmits energy only through the bushing  28  which absorbs this energy. Through this, isolation, twisting, torquing or excess vibration transmitted to the running board  12  is greatly reduced, thus extending the life of each running board  12  significantly.  
         [0037]      FIG. 7  illustrates the assembled mounting system  26  on opposite ends of the running board  12 .  
         [0038]     Although only one pair of mounting systems  26  is shown in  FIG. 7  or the running board  12 , it should be understood that multiple mounting systems are utilized with each running board  12  depending upon the length and size of the running board  12 . It is contemplated by the inventor that a running board  12  will be provided with the bushing  28  and insert  40  attached by the bolt  46  such that the running board  12  can be installed on the existing bracket  16  by simply tightening the nut  58  to each of the shafts  42  of the inserts  40 . In this manner, the tightening of the bolts  46  with respect to the bushings  28  can be controlled during manufacture.  
         [0039]     In the foregoing description, the railroad car support surface has been set forth in terms of running board  12 . However, it should be understood that the term support surface is intended to further embrace various steps as well as platforms and similar support structures to be secured on a railroad car by the mounting system  26  of the present invention.  
         [0040]     Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.