Railroad freight car sidebearing

Abstract

An improved side bearing for railway cars is provided that achieves improved tracking and curving by the limitation of rock of the railway car. The side bearing comprises a base with a generally upwardly extending wall portion. A cap comprising a top section with generally downwardly extending wall portion is provided. The cap extends into or around the wall section of the base. A spring is provided within the base that extends to the underside and supports the cap. A base insert is provided of varying thickness to support springs of the same preselected height to provide preselected varying load capacities.

What is claimed is: 
     
         1 . A side bearing for use in a railway car truck,
 the side bearing comprising:   a base section having a base bottom portion and a base wall structure extending generally upward from the base bottom portion,   the base wall structure forming a base receiving structure having an open top,   a spring positioned in the base receiving structure of the base section, the spring having a preselected non-compressed height,   a cap having a generally flat top portion and a cap wall structure extending generally downward from the top portion, the cap wall structure forming a cap receiving structure having an open bottom,   and a base insert positioned within the base receiving structure, the base insert comprising a main section having a top surface, the main section having a preselected thickness, and wherein the spring has a bottom surface supported on the top surface of the main section of the base insert.   
     
     
         2 . The side bearing of  claim 1   wherein the base insert is a unitary structure having a generally cylindrical main section,   a first wing section extending laterally from the main section,   a second wing structure extending laterally from the main section at an angle of about 180 degrees from the first wing section,   and wherein the main section of the base insert has a pre-determined thickness.   
     
     
         3 . The side bearing of  claim 2   wherein the base insert is comprised of a structural plastic.   
     
     
         4 . The side bearing of  claim 2   wherein the thickness of the main section of the base insert varies with a predetermined load rating of the base insert.   
     
     
         5 . The side bearing of  claim 2  wherein the thickness of the main section of the base insert varies between 0.11 inch (0.28 cm) and 0.33 inch (0.84 cm). 
     
     
         6 . The side bearing of  claim 2   wherein the base wall structure of the base section of the side bearing has an opening therein,   and wherein the first wing section of the base insert has an indication of a load rating   therein, such that the load rating of the base insert is visible through the opening in the base wall structure.   
     
     
         7 . The side bearing of  claim 1   wherein the spring is comprised of a generally cylindrical shaped, unitary elastomer structure.   
     
     
         8 . The side bearing of  claim 7   wherein the spring includes a bottom surface, and the bottom surface of the spring contacts and is supported by the top surface of the main section of the base insert.   
     
     
         9 . The side bearing of  claim 7 ,
 wherein the base insert has a thickness of 0.11 inch (0.28 cm), the spring has a pre-compressed height of 4.45 inch (11.3 cm), and the spring has a fully compressed height under maximum load of 3.82 inch (9.7 cm).   
     
     
         10 . The side bearing of  claim 7 ,
 wherein the base insert has a thickness of 0.33 inch (0.84 cm), the spring has a pre-compressed height of 4.23 inch (10.7 cm) and the spring has a fully compressed height under maximum load of 3.60 inch (9.1 cm).   
     
     
         11 . The side bearing of  claim 7   wherein the base insert has a thickness of 0.178 inch (0.45 cm), the spring has a pre-compressed height of 4.38 inch (11.1 cm) and the spring has a fully compressed height under maximum load of 3.75 inch (9.5 cm).   
     
     
         12 . A side bearing for use in a railway car truck,
 the side bearing comprising a base section having a base bottom portion and a base wall structure extending generally upward from the base bottom portion,   the base wall structure forming a base receiving structure having an open top,   a spring positioned in the base receiving structure of the base section, the spring having a pre-selected, non-compressed height,   a cap having a generally flat top portion and a cap wall structure extending generally downward from the top portion, the cap wall structure forming a cap receiving structure having an open bottom,   and a base insert positioned within the base receiving structure,   the base insert comprising a generally circular main section of a predetermined thickness,   the main section having a top surface and a generally cylindrical wall extending upwardly from the main section to form an upwardly facing base insert receiving structure.   
     
     
         13 . The side bearing of  claim 12   wherein the spring has a bottom surface supported on the top surface of the main section of the base insert.   
     
     
         14 . The side bearing of  claim 12   wherein the base insert is a unitary structure having a generally cylindrical main section,   a first wing section extending laterally from the main section,   a second wing structure extending laterally from the main section at an angle of about 180 degrees from the first wing section,   and wherein the main section of the base insert has a pre-determined thickness.   
     
     
         15 . The side bearing of  claim 14   wherein the base insert is comprised of a structural plastic.   
     
     
         16 . The side bearing of  claim 14   wherein the thickness of the main section of the base insert varies with a predetermined load rating of the base insert.   
     
     
         17 . The side bearing of  claim 14   wherein the thickness of the main section of the base insert varies between 0.11 inch (0.28 cm) and 0.33 inch (0.84 cm).   
     
     
         18 . The side bearing of  claim 14   wherein the base wall structure of the base section of the side bearing has an opening therein,   and wherein the first wing section of the base insert has an indication of a load rating   therein, such that the load rating of the base insert is visible through the opening in the base wall structure.   
     
     
         19 . The side bearing of  claim 12   wherein the spring is comprised of a generally cylindrical shaped, unitary elastomer structure.