Friction shoe with damping for a railway car truck

Abstract

A rail vehicle with two sideframes and a bolster as the freight car truck has limits on stability. A railway freight car truck having a friction shoe with a constant force device acting directly on the shoe flat surface is provided, such that the friction shoe is forced to remain in contact with the side frame mating vertical surface. The control spring acting on the friction shoe which applies a varying force to the side frame mating surface. The damping of the friction shoe is retained when there is less variable force of friction, which decreases vertical acceleration of the rail vehicle, providing high speed stability for most track conditions.

What is claimed is: 
     
         1 . A railway car truck comprising
 a sideframe having a substantially upright column partially defining a center opening,   a bolster having an end supported in the sideframe center opening for vertical movement therein,   a vertical surface on the sideframe column, and a first wear plate attached to the vertical surface on the sideframe column,   sloped surfaces on the bolster,   a friction shoe comprising a substantially vertical surface and a sloped surface extending at an acute angle with the vertical surface,   a vertical spring urging the friction shoe sloped surface into engagement with the first wear plate on the sideframe column and with the sloped surface of the bolster,   and a horizontal spring urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column.   
     
     
         2 . The railway truck of  claim 1  wherein
 the horizontal spring provides a constant lateral force urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column. 
 
     
     
         3 . The railway truck of  claim 1  wherein
 the vertical spring provides a variable force urging the friction shoe sloped surface into engagement with the sloped surface of the bolster. 
 
     
     
         4 . The railway truck of  claim 1  wherein
 the friction shoe provides both constant and variable damping to vertical movement of the bolster in the sideframe center opening. 
 
     
     
         5 . The railway truck of  claim 4  wherein
 the friction shoe provides forces acting on the bolster to assist in keeping the bolster in a transverse relationship to the sideframe. 
 
     
     
         6 . The railway truck of  claim 4  wherein
 the friction shoe provides forces acting on the bolster to assist in keeping the bolster and sideframe from moving into a parallelogram relationship. 
 
     
     
         7 . A railway car truck comprising
 a sideframe having a substantially upright column partially defining a center opening,   a bolster having an end supported in the sideframe center opening for vertical movement therein,   a vertical surface on the sideframe column,   sloped surfaces on the bolster,   a friction shoe comprising a substantially vertical surface and a sloped surface extending at an acute angle with the vertical surface,   a spring urging the friction shoe sloped surface into engagement with the vertical surface on the sideframe column and with the sloped surface of the bolster.   
     
     
         8 . The railway truck of  claim 7  further comprising
 a first wear plate attached to the vertical surface on the sideframe column. 
 
     
     
         9 . The railway truck of  claim 8  wherein
 the horizontal spring provides a constant lateral force urging the friction shoe vertical surface into engagement with the first wear plate on the sideframe column. 
 
     
     
         10 . The railway truck of  claim 7  wherein
 the vertical spring provides a variable force urging the friction shoe sloped surface into engagement with the sloped surface of the bolster. 
 
     
     
         11 . The railway truck of  claim 7  wherein
 the friction shoe provides both constant and variable damping to vertical movement of the bolster in the sideframe center opening. 
 
     
     
         12 . The railway truck of  claim 11  wherein
 the friction shoe provides forces acting on the bolster to assist in keeping the bolster in a transverse relationship to the sideframe. 
 
     
     
         13 . The railway truck of  claim 11  wherein
 the friction shoe provides forces acting on the bolster to assist in keeping the bolster and sideframe from moving into a parallelogram relationship.