Low profile shear pad and adapter
A low profile mounting assembly for use between a rail car side frame pedestal and the rail car roller bearing includes a shear pad and a bearing adapter. In one embodiment, the shear pad has relatively thin plates joined by an elastomeric layer. In another embodiment, the shear pad includes a projection extending downwardly from a plate to be received and retained by a recess defined in a top surface of the adapter. In another embodiment, a central cavity formed in a lower plate of the shear pad cooperates with the adapter top surface to distribute forces on the roller bearing. In another embodiment, an elastomeric projection of a shear pad plate bears against ridges on the adapter top surface to prevent disengagement.
1. A low profile mounting assembly for use between a rail car side frame pedestal and a rail car axle bearing, comprising:
a roller bearing adapter including a bottom surface adapted to engage a rail car axle bearing and a top surface, the top and bottom surfaces being configured to add a maximum height substantially equal to 0.80 inches to the height of the mounting assembly; and
a shear pad assembly including an upper plate adapted to engage a side frame pedestal, a lower plate adapted to engage the top surface of a roller bearing adapter and only an elastomeric layer positioned intermediate the upper and lower plates, the shear pad assembly being configured to add a maximum thickness substantially equal to 0.50 inches to the height of the mounting assembly.
2. The mounting assembly of claim 1 wherein the upper and lower plates each have a thickness substantially equal to 0.125 inches and the elastomeric layer has a thickness substantially equal to 0.25 inches.
3. The mounting assembly of claim 1 wherein the upper and lower plates each have a thickness substantially equal to 0.0625 inches and the elastomeric layer has a thickness substantially equal to 0.375 inches.
4. The mounting assembly of claim 3 wherein the roller bearing adapter's top surface has a width no less than the width of the elastomeric layer.
5. The mounting assembly of claim 1 wherein the roller bearing adapter's top surface has a width no less than the width of the elastomeric layer.
6. A low profile shear pad for use between a rail car side frame pedestal and a rail car roller bearing adapter, comprising:
an upper plate adapted to engage a side frame pedestal;
a lower plate adapted to engage the top surface of a roller bearing adapter; and
an elastomeric layer joining the upper and lower plates, the elastomeric layer having side edges and end edges, the end edges having an arcuate shape which includes an upper portion tangent to a bottom surface of the upper plate and a lower portion tangent to a top surface of the lower plate.
7. The shear pad of claim 6 wherein the radius of the end edge upper and lower portions is equal to half the separation between the upper and lower plates.
8. The shear pad of claim 7 wherein the radius of the end edge upper and lower portions is substantially equal to 0.13 inches.
9. The shear pad of claim 6 , wherein the side edges and the end edges of the elastomeric layer have an arcuate shape.
10. The shear pad of claim 9 , wherein the side edges and the end edges of the elastomeric layer have a concave curvature.
11. A low profile mounting assembly for use between a rail car side frame pedestal and a rail car axle bearing, comprising:
a roller bearing adapter including a bottom surface adapted to engage a rail car axle bearing and a generally planar, high friction top surface defining a plurality of ridges; and
a shear pad assembly including a top surface adapted to engage a rail car side frame pedestal and a bottom surface defining a downwardly extending projection substantially comprised of an elastomeric material and adapted to bear against the ridges without extending below the top surface of the roller bearing adapter when the shear pad assembly is positioned onto the roller bearing adapter.
12. The low profile mounting assembly of claim 11 , wherein the projection has a generally uniform thickness and the ridges have a generally uniform maximum height.
13. The low profile mounting assembly of claim 11 , wherein the ridges are arranged in a generally uniform distribution.
14. The low profile mounting assembly of claim 11 , wherein the ridges are arranged in a generally symmetrical distribution.
15. A low profile mounting assembly for use between a rail car side frame pedestal and a rail car axle bearing, comprising:
a roller bearing adapter including a bottom surface adapted to engage a rail car axle bearing and a generally planar, high friction top surface defining a plurality of ridges, wherein the ridges comprise metallic extensions from the top surface of the roller bearing adapter; and
a shear pad assembly including a top surface adapted to engage a rail car side frame pedestal and a bottom surface defining a downwardly extending projection substantially comprised of an elastomeric material and adapted to bear against the ridges to prevent disengagement of the roller bearing adapter and the shear pad assembly.
16. A low profile mounting assembly for use between a rail car side frame pedestal and a rail car axle bearing, comprising:
a roller bearing adapter including a bottom surface adapted to engage a rail car axle bearing and a generally planar, high friction top surface defining a plurality of ridges, wherein the ridges comprise polymeric extensions from the top surface of the roller bearing adapter; and
a shear pad assembly including a top surface adapted to engage a rail car side frame pedestal and a bottom surface defining a downwardly extending projection substantially comprised of an elastomeric material and adapted to bear against the ridges to prevent disengagement of the roller bearing adapter and the shear pad assembly.
17. The low profile mounting assembly of claim 16 , wherein the projection includes a lower metallic pad adapted to bear against the ridges.