Abstract:
A one-piece, cast traction pin for use with railway cars. The traction pin is used to connect the railcar cab with the railcar truck assembly. The traction pin includes a mounting plate cast integral with the pin, thereby eliminating the use of multiple welded plates. The one-piece cast traction pin is also solid to reduce the potential for stress related failure of the traction pin during normal operation of the railway car.

Description:
This application claims priority to U.S. Provisional Application Ser. No. 60/207,080, filed May 25, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally to traction pins for railway car assemblies. More particularly, the present invention is directed to a cast, one-piece traction pin. 
     BACKGROUND OF THE INVENTION 
     The prior art traction pin assembly is a multi-piece component that connects a railcar cab or house assembly to the railcar truck. As conventional, the traction pin assembly is welded to the underside of the railcar cab and engages the railcar truck assembly permitting the truck assembly to turn, or swivel, independently of the cab. 
     As is known in the art, the traction pin assembly includes several components that are welded together and to the railcar cab. These components include a cylindrical pin and multiple mounting plates. The pin is welded to the mounting plates which, in turn, are welded to the underframe of the railcar cab. The mounted traction pin assembly is then received in a mating opening in the railcar truck to complete the joinder of the cab to the truck assembly. Once assembled, the traction pin permits rotatable movement of the railcar cab relative to the truck assembly. 
     Known drawbacks exist with respect to the conventional traction pin assemblies. By way of example, the use of multiple plates to attach the traction pin to the railcar cab add significant assembly time, labor, and expense. In addition, the multiple plates, which are typically made from rolled steel, have mechanical properties that are very dependent on the rolling direction of the plate. As a result, the mechanical properties may vary for each mounting plate used in a traction pin assembly. Also, known traction pins are hollow and thus define a wall that must have a critical wall thickness to withstand stresses encounted during normal operation of the railcar. Because the traction pin is made from cast steel, variations in wall thickness may occur. As such, if the wall thickness of the traction pin becomes too thin, there exists the potential for a failure of the traction pin. These and other known problems with existing traction pin assemblies are overcome with the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to eliminate the multiple components needed to mount the traction pin to the underframe of the railcar cab. 
     It is another object to reduce the time, labor and expense involved in mounting the traction pin to the railcar body. 
     It is a further object of the present invention to prevent stress related failure in the traction pin. 
     Yet a further object of the invention is to eliminate the problems associated with rolled plates used to mount the traction pin. 
     Still a further object is to provide a one-piece traction pin having a solid unitary structure. 
     In one embodiment, the present invention includes a one-piece, cast traction pin having a mounting plate cast integral with the pin. In an exemplary embodiment, the cast pin is solid, thereby reducing if not eliminating the potential for stress related failure of the pin during normal operation. With the present invention, the use of multiple rolled plates, which are welded together, and the disadvantages associated with such rolled plates are eliminated. 
     The full range of objects, aspects and advantages of the invention are only appreciated by a full reading of this specification and a full understanding of the invention. Therefore, to complete this specification, a detailed description of the invention follows, after a brief description of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a prior art assembly of the railcar cab and truck. 
         FIG. 2  shows an isometric view of a prior art traction pin assembly. 
         FIG. 3  shows another isometric view of the prior art assembly of FIG.  2 . 
         FIG. 4  shows an isometric view of the prior art traction pin of FIG.  2 . 
         FIG. 5  shows an isometric view of a prior art traction pin assembly. 
         FIG. 6  shows an isometric view of a traction pin of the present invention. 
         FIG. 7  shows an isometric view of a traction pin assembly of the present invention. 
         FIG. 8  shows another isometric view of a traction pin assembly of the present invention. 
         FIG. 9  shows an isometric view of an alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the figures wherein like numerals indicate like elements, there is shown in  FIG. 1  a railcar cab  10  and truck assembly  12 . Located between and joining the railcar cab and truck assembly is a traction pin  14 . As known by those of skill in the art, the traction pin serves to join the cab and truck assembly and permit rotatable movement of the cab relative to the truck assembly. 
     Referring to  FIGS. 2-4 , there is depicted a prior art traction pin assembly  20  used to join a railcar cab and truck assembly. The prior art traction pin assembly includes a traction pin  22  and multiple plates welded to the traction pin  22 . As conventional, the traction pin  22  is welded to a circular steel plate  24  and a square steel plate  26 . The plates  24 ,  26  are, in turn, welded to the underframe of the cab or house assembly of the railcar. The steel plates  24 ,  26  are typically roll formed by a rolling mill and thus have mechanical properties dependent on the direction of the roll. 
     Referring to  FIG. 5 , the traction pin assembly  20  is mounted to several components of the underframe of the cab. As depicted, the square steel plate  26  is welded to bottom plate  50 . Plate  50  is welded to main sills  52  which are located between the bottom plate  50  and a top plate  54 . Reinforcing members  56  are also located between the circular plate  24  and the top plate  54 . The top plate  54  is welded to the underframe of the railcar cab. 
     Referring back to  FIG. 4 , as is known in the art, the traction pin  22  typically includes a cylindrical shaft  40 , a frustum region  42  that flares outwardly from the cylindrical shaft to an outer circular rim  44 . As known by those skilled in the art, the prior art traction pin  22  forms a hollow opening or cavity  46  within the traction pin. Because the pin  22  includes the opening  46 , the pin defines a cylindrical wall that must have a wall thickness to withstand the stresses encounted by the pin during normal operation of the railcar. 
     As stated above, as assembled, the shaft  40  of the pin  22  is received in a mating opening in the housing of the truck casting, not shown, to mount the railcar cab to the truck assembly. The pin  22  thus permits the rotatable movement of the cab relative to the truck assembly. 
     Referring to  FIG. 6 , there is depicted one embodiment of the present invention. As depicted, a traction pin  60  includes a cast, one-piece pin body  62  with an integral mounting plate  64 . As cast, the hollow opening or cavity previously formed in conventional traction pins is now filled-in with steel, creating a solid pin. The solid pin reduces, if not eliminates, the potential for traction pin failure. The pin body is cylindrical and may include a tapered end  66 . The pin body  62  may also include a frustum shaped or flared region  68  extending outwardly from the pin body. The frustum region  68  flares outwardly to form and define the mounting plate  64 . In other words, the frustum region is formed integral with the mounting plate. The mounting plate  64 , as depicted, is circular in shape. However, it will be understood by those of skill in the art that the mounting plate is not limited to a circular shape. Other non-circular shapes for the plate  64  may be used with the present invention. It will be further understood by those skilled in the art that other shapes of the pin body, including the frustum region, are possible with the present invention. 
     Referring to  FIG. 7 , the traction pin  60  is welded to a mounting plate  70  having a central opening  72 . As depicted, the mounting plate  70  is rectangular in shape and includes a circular opening  72 . Again, those of skill in the art will recognize that the present invention is not limited to the shape of the plate or opening as depicted in FIG.  7 . 
     As shown in  FIG. 8 , the mounting plate  70  is welded to bottom plate  80 . The plate  80  may be welded to main sills  82  which are located between the bottom plate  80  and a top plate  84 . Similar to the assembly depicted in  FIG. 5 , reinforcing members  86  may be located between the circular plate  64  of the traction pin  60  and the top plate  84 . As conventional, the top plate  84  is welded to the underframe of the railcar cab. 
     Significantly, the integral one-piece traction pin eliminates the multiple welded plates and the disadvantages associated with the use of such plates. In addition, with the inventive cast traction pin, the problems encounted with the traction pin having a hollow interior and with the use of roll formed plates are also eliminated. 
     Referring to  FIG. 9 , there is depicted an alternative embodiment of the present invention. With this embodiment, the plate  70 , depicted in  FIG. 7 , is cast integral with the traction pin  60 , depicted in FIG.  6 . Specifically, a traction pin  90  is illustrated and includes a cast, one-piece pin body  92  with an integral mounting plate  94 . As with the embodiment of  FIG. 6 , the hollow opening or cavity previously formed in conventional traction pins is filled-in with steel, creating a solid pin having a unitary structure. In this embodiment, the pin body is again cylindrical and may include a tapered end  96 . The pin body  92  may also include a frustum shaped or flared region  98  extending outwardly from the pin body. The frustum region  98  flares outwardly and is formed integral with the mounting plate  94 . As depicted, the mounting plate  94  has a rectangular or non-circular shape. However, one skilled in the art will understand that other shapes and configurations for the plate  94  may be used with the invention and are considered to be within the scope of the same. Located on the top surface of the mounting plate  94  are raised surfaces  100  that are machined flat to enhance the mounting or welding of the reinforcing members  86 , described above, to the mounting plate  94 . Note that the invention may be used without the machined surfaces  100  if reinforcing members  86  are not used as part of the traction pin assembly. 
     While the invention has been described with respect to specific embodiments, those skilled in the art will appreciate and understand that there are numerous variations and permutations of the above described embodiments that fall within the spirit and scope of the invention as set forth in the appended claims.