Abstract:
There is disclosed a lightweight truck sideframe for use in a railway car. The truck sideframe is of lighter weight than conventional truck sideframes because of the removal of the double wall of the truck sideframe tension member, leaving a single wall tension member. Removal of this significant mass of metal requires reinforcement of the truck sideframe in several areas including in the tension member below the spring seat, in the compression member, and at the side wall window. The resulting truck sideframe construction is of lighter weight than conventional truck sideframes and exceeds the Association of American Railroad&#39;s requirements for strength and durability.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to improved truck sideframes for railway cars. More specifically, but without restriction to the particular use which is shown and described, this invention relates to a lighter weight truck sideframe. 
     2. Description of the Related Art 
     As conventional, railcar trucks are the wheeled vehicles that ride on the tracks and support the railcar body. Each truck includes wheel sets which include two wheels spaced transversely from each other and joined by a transversely extending axle. Transversely spaced truck sideframes are supported on the wheel sets. The truck sideframes are longitudinally elongated and define longitudinally spaced, downwardly opening pedestal jaws which are mounted on the journal bearings of the wheel sets. Transversely extending between each truck sideframe is a bolster on which is mounted the car body. 
     The Association of American Railroads (“A.A.R.”) sets forth structural requirements for the various components of the trucks, including the truck sideframes. The requirements for the truck sideframe include specific strength and fatigue resistant capabilities for extended service of the truck sideframe. Because the railcar truck sideframes must exhibit high strength, truck sideframes are conventionally made of cast steel, which contributes a significant part of the total weight of the railway car. In the rail line shipping industry, weight limits are placed on shippers of goods for preserving the safety and conditions of the track. Consequently, the quantity of goods that may be carried by a railcar is affected by the total weight of the railcar body, the trucks and accompanying railcar components, such as the truck sideframe. Accordingly, a reduction in the weight of the railcars, including the truck sideframes, will result in an increase in the total capacity of goods shipped by a rail line owner. Therefore, it is highly desirable to reduce the weight of the truck sideframe while maintaining the strength and fatigue resistance capabilities of the sideframe, as required by the A.A.R. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to reduce the overall weight of a railway car by reducing the weight of the truck sideframe. It is another object of the invention to reduce the weight of the truck sideframe without a decrease in strength or durability. Yet another object of the invention is to minimize core seams and core shifting by reducing the number of cores used. Still another object of the present invention is to minimize chaplets in the drag by setting the core in the mold on its prints. 
     Briefly stated, the present invention involves lightening the truck sideframe by removing the double wall of the truck sideframe tension member. Removing this significant mass of metal requires reinforcement of the truck sideframe in the following areas: 1) extending the rib under the spring seat out to the column wear plate wall; 2) increasing the thickness under the radius at the spring seat in the side wall; 3) increasing the width of the truck sideframe at its centerline; 4) increasing the depth of the truck sideframe at its centerline; 5) locally sloping the top compression member toward the side walls and locally increasing the interior radius between the sloped top compression member and each side wall to prevent the top compression member from buckling; and 6) splitting the side window with a reinforcing rib, the reinforcing rib defining a raised portion to prevent the sidewall from buckling. Significantly, with these truck sideframe modifications, the resulting truck sideframe construction is of lighter weight than conventional truck sideframes and exceeds the A.A.R. requirements for strength and durability. 
     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 
     The embodiments of the invention will be described in relation to the accompanying drawings. In the drawings, the following figures have the following general nature: 
     FIG. 1 is a cross-section view of a prior art truck sideframe. 
     FIG. 2 is a side view of the truck sideframe of the present invention. 
     FIG. 3 is a half top view and a half bottom view of the truck sideframe of FIG.  2 . 
     FIG. 4 is an isometric partial view of the truck sideframe of FIG.  2 . 
     FIG. 5 is an isometric partial view of the truck sideframe of FIG.  2 . 
     FIG. 6 is a cross-section side view of the truck sideframe of FIG.  2 . 
     FIG. 7 is a cross-section view of the top compression member of the truck sideframe of FIG. 3 taken at line  7 — 7 . 
     FIG. 8 is a partial side view of an alternative embodiment of the present invention. 
    
    
     In the accompanying drawings, like reference numerals are used throughout the various figures for identical structures. 
     DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, there is shown a cast railway truck sideframe  10  common to the railroad industry. For a better understanding of the present invention, the prior art truck sideframe  10  will first be described followed by the inventive truck sideframe and the structural differences and weight savings gained by the improved truck sideframe. The conventional truck sideframe  10 , as illustrated in partial cut-out view in FIG. 1, defines a top compression member  12  extending along the longitudinal length of the sideframe, and a lower tension member  14  generally parallel to the compression member  12 . The lower tension member  14  includes a diagonally extending double-wall arm  16  which extends to downwardly extending pedestal jaws  18  and  19 . The pedestal jaws define the axle-accommodating pedestal opening  20  wherein the bearing adapters (not shown) of the railcar wheels are mounted. 
     It is also conventional that a vertical rib  22  extends between the tension and compression members. The vertical ribs of the truck sideframe define the truck bolster opening  24  through which is mounted the truck bolster (not shown). The vertical ribs are joined to the tension and compression members at the bend points  26 ,  28 . The wall of the tension member at these bend points  26 ,  28  typically has a uniform thickness, the significance of which is discussed below. The vertical rib further defines a wear plate area  31 . Formed between the vertical ribs of the truck sideframe along the tension member is the bolster spring seat  30  on which is mounted the bolster springs (not shown). As previously stated, the truck bolster is mounted between the truck sideframes, extending through the bolster opening  24 . The truck bolster is supported by the bolster springs which are mounted on the bolster spring seat  30 . Located along the side walls of the truck sideframe bounded by the compression and tension members and the vertical ribs are lightener holes  32  which provide weight savings for the truck sideframe and access to the brake shoes (not shown). Other weight saving lightener holes  34 ,  36  are located on the truck sideframe in the compression member and tension member, respectively. 
     As depicted in FIG. 1, the known truck sideframe includes a tension member that defines two tension walls  38 ,  40  which extend the entire length of the tension member, forming the diagonally extending double-wall arm  16 . The cross-sectional thickness of the tension walls  38 ,  40  vary depending on the rated railcar truck tonnage. The tension walls, and side walls  41  in the tension member define a tension core  43 . The core  43  extends the entire length of the tension member including the diagonal arms  16 . The double tension wall, while providing structural integrity to the truck sideframe, adds significantly to the overall weight of the truck sideframe. As discussed below, the present invention eliminates the double tension wall to reduce the overall weight of the truck sideframe while maintaining the structural integrity of the sideframe. Located between and connecting the tension walls  38 ,  40  is a vertical spring seat support rib  42 . The support rib  42  is located directly below the spring seat  30  at the centerline of the truck sideframe to add structural support and strength to the tension member. 
     Referring to FIGS. 2-8, there is disclosed an exemplary embodiment of the truck sideframe  60  of the present invention. As with conventional truck sideframes, the truck sideframe  60  defines an upper compression member  62 , and a lower tension member  64  defining diagonally extending support arms  66 . The support arms  66  and compression member terminate to form downwardly extending pedestal jaws  68 ,  70 . The pedestal jaws define the axle-accommodating pedestal opening  72  wherein the bearing adapters (not shown) of the railcar wheels are mounted. The truck sideframe  60  defines side walls  74  and lightener holes  76  in the side walls. Other lightener holes  78  are located in the compression and tension members. Located and extending between the compression and tension members are vertical ribs  80  which further define bolster wear plates  82 . 
     As previously stated, the subject matter of the present invention is directed to reducing the overall weight of the truck sideframe through various structural changes to the sideframe. Specifically, the most significant structural change from the conventional truck sideframe is the removal of the double wall in the tension member, replacing it with a single tension member construction. As exemplified in FIG. 4, a single tension wall  84  extends from the bottom wall  86  of the compression member below the spring seat  89  to the pedestal jaw  70 . That is, the diagonally extending support arms  66  are a single wall construction. To maintain the structural strength of the truck sideframe, additional structural changes are made to the conventional truck sideframe including extending the rib  88 , which is located under the bolster spring seat  89 , the entire length of the spring seat. In other words, the rib  88  is extended from a point directly below one of the vertical ribs to a point directly below the other vertical rib. In addition, a reinforcing rib  90  is located along the side walls  74  at the lightener hole  76  splitting the lightener hole into two lightener holes. The reinforcing rib is located diagonally across the lightener hole and defines a parabolic cross-section with the maximum material thickness at the middle of the rib. The reinforcing rib  88  prevents the side walls  74  from buckling under a loaded condition. Still further structural changes of the present invention include increasing the wall thickness of the truck sideframe at various locations. The thickness of the side wall  74  is increased near the radius  94  where the vertical rib  80  joins with the bolster spring seat plate  89 . In addition, the thickness of the spring seat plate  89  is increased at the radius  94 . Further, material is added at centerline  100  of the truck sideframe increasing the width and depth of the sideframe at the centerline. To prevent local buckling of the top compression member  62 , the compression member is locally reinforced at  96  outboard of the bolster opening  101 , as shown in FIG. 6, by sloping the top compression member  62  toward the side walls  74  and increasing the interior radii  102  between the top compression member and the side walls, as depicted in FIG.  7 . The increase in the radii  102  results in the wall thickness of the sideframe at the radii  102  being greater than the wall thickness of the adjoining compression member  62  and side walls  74 . 
     The aforementioned structural changes maintain the structural integrity of the truck sideframe while decreasing the overall weight of the sideframe. It will be understood by one skilled in the art that variations of the illustrated truck sideframe are possible without being outside the scope of the present invention. Except for the above mentioned features of the present invention, the remaining features of the truck sideframe  60  are conventional. 
     Significantly, the removal of the second tension wall reduces the number of casting cores. With a fewer number of cores, problems encountered during the pouring process, such as, core shifting, which leads to casting flaws, offsets and dimensional inconsistencies are reduced. In addition, stress concentrations which develop at these casting flaws and offsets and which are a primary reason for metal fatigue, are also reduced. With fewer cores, manufacturing is improved, resulting in an increase in production efficiency. Furthermore, with the core arrangement of the present invention, fewer chaplets are needed to support the core. Instead, the mold supports the core minimizing problems such as stress concentrations around the chaplets and chaplet scars or lack of fusion of the chaplets to the casting. Still further, finishing of the chaplet scars is reduced by minimizing the number of chaplets. 
     Referring to FIG. 8, there is disclosed an alternative embodiment of the present invention. As depicted, this embodiment illustrates the removal of the reinforcing rib  90  and the use of a lightener hole  103  in the side walls  74 . In this arrangement, the lightener hole  103  is elliptically shaped and aligned at approximately the same angle as the diagonally extending support arms  66 . The remaining construction of the embodiment depicted in FIG. 8 is the same as the embodiment depicted in FIG.  2 . 
     It will be understood by one skilled in the art that variations to the present invention are possible without being outside the scope of the invention. Therefore, to particularly point out and distinctly claim the subject matter regarded as the invention, the following claims conclude the specification.