Slack adjuster for railcar brake

Abstract

A slack adjuster for railroad car braking system is provided. The slack adjuster includes a first jaw positioned at a first end of the slack adjuster and a second jaw positioned at a second end of the slack adjuster. A rod assembly is attached to the first jaw and a tube is attached to the second jaw. A nut assembly is provided for transferring a force between the rod assembly and the tube. One or more components configured to bear an axial load of the slack adjuster are attached to the tube by crimping at least a portion of the tube into a groove defined in an outer surface of such component.

What is claimed is: 
     
         1 . A slack adjuster for a railroad car braking system defining an axial direction and a circumferential direction, the slack adjuster comprising:
 a first jaw;   a rod assembly attached to the first jaw;   a nut assembly having at least a portion rotatably engaged with the rod assembly;   a tube attached to the nut assembly and extending generally along the axial direction between a first end and a second end, the tube enclosing at least a portion of the rod assembly; and   a second jaw including a base attached to the second end of the tube, the base of the second jaw defining a groove therein extending generally along the circumferential direction, at least a portion of the tube crimped into the groove in the base of the second jaw attaching the tube to the base of the second jaw.   
     
     
         2 . The slack adjuster of  claim 1 , wherein the base of the second jaw defines a central opening and is a solid component between the central opening and the groove, free from any opening or holes. 
     
     
         3 . The slack adjuster of  claim 1 , wherein the groove in the base of the second jaw defines an inner edge having a radius greater than or equal to about ⅛th of an inch. 
     
     
         4 . The slack adjuster of  claim 1 , wherein the nut assembly includes a nut defining a threaded opening rotatably engaged with a threaded portion of the rod assembly, a first bearing collar, and a second bearing collar, wherein the first and second bearing collars are disposed on opposite sides of the nut along the axial direction for constraining the nut along the axial direction of the slack adjuster relative to the tube, 
     
     
         5 . The slack adjuster of  claim 4 , wherein the first bearing collar defines a groove in an outer surface extending generally along the circumferential direction, and wherein at least a portion of the tube is crimped into the groove in the first bearing collar attaching the tube to the first bearing collar. 
     
     
         6 . The slack adjuster of  claim 5 , wherein the first bearing collar defines a center opening through which a portion of the rod assembly extends, and wherein the first bearing collar is a solid component between the center opening and the groove, free from any opening or holes. 
     
     
         7 . The slack adjuster of  claim 5 , wherein the groove in the first hearing collar defines an inner edge having a radius greater than or equal to about ⅛th of an inch. 
     
     
         8 . The slack adjuster of  claim 5 , wherein the second bearing collar also defines a groove in an outer surface extending generally along the circumferential direction, and wherein at least a portion of the tube is crimped into the groove in the second bearing collar attaching the tube to the second bearing collar. 
     
     
         9 . The slack adjuster of  claim 8 , wherein the second bearing collar defines a center opening through which a portion of the rod assembly extends, and wherein the second bearing collar is a solid component between the center opening and the groove, free from any opening or holes. 
     
     
         10 . The slack adjuster of  claim 8 , wherein the groove in the first bearing collar defines an inner edge having a radius greater than or equal to about ⅛th of an inch, and wherein the groove in the second bearing collar also defines an inner edge having a radius greater than or equal to about ⅛th of an inch. 
     
     
         11 . The slack adjuster of  claim 4 , further comprising
 a pawl box including at least one locator tab and at least one coupling projection, wherein the tube defines at least one pawl opening adjacent to the nut of the nut assembly and at least one locator opening positioned adjacent to the at least one pawl opening, wherein the pawl box is attached to the tube by positioning the pawl box over the at least one pawl opening such that the at least one locator tab of the pawl box extend into the at least one locator opening and by forming the at least two coupling projections of the pawl box around an outer surface of the tube.   
     
     
         12 . The slack adjuster of  claim 1 , further comprising
 an end cap defining a groove extending generally along the circumferential direction, at least a portion of the rod assembly slidably extending through the end cap, wherein at least a portion of the tube is crimped into the groove in the end cap attaching the tube to the end cap.   
     
     
         13 . A slack adjuster for a railroad car braking system defining an axial direction and a circumferential direction, the slack adjuster comprising:
 a first jaw and a second jaw, the first jaw positioned at a first end of the slack adjuster along the axial direction and the second jaw positioned at a second end of the slack adjuster along the axial direction;   a rod assembly attached to the first jaw and extending generally along the axial direction;   a tube attached to the second jaw and also extending generally along the axial direction; and   a nut assembly configured to transfer a force between the rod assembly and the tube, the nut assembly including a first bearing collar defining a groove therein extending generally along the circumferential direction, at least a portion of the tube crimped into the groove in the first bearing collar attaching the tube to the first bearing collar.   
     
     
         14 . The slack adjuster of  claim 13 , wherein the nut assembly further includes a second bearing collar also defining a groove therein extending generally along the circumferential direction, wherein at least a portion of the tube is crimped into the groove in the second bearing collar attaching the tube to the second bearing collar. 
     
     
         15 . The slack adjuster of  claim 13 , wherein the second jaw includes a base defining a groove therein extending generally along the circumferential direction, wherein at least a portion of the tube is crimped into the groove in the base of the second jaw attaching the tube to the base of the second jaw. 
     
     
         16 . A method for manufacturing a slack adjuster for a railroad car braking system, the slack adjuster defining an axial direction, the method comprising:
 attaching a first jaw to a rod assembly;   positioning a nut assembly over a threaded portion of the rod assembly;   attaching the nut assembly to a tube extending generally along the axial direction such that at least a portion of the nut assembly is fixed along the axial direction relative to the tube; and   attaching the tube to a base of a second jaw by crimping a portion of the tube into a groove defined in the base of the second jaw, fixing the base of the second jaw to the tube.   
     
     
         17 . The method of  claim 16 , wherein the nut assembly includes a nut defining a threaded opening rotatably engaged with the threaded portion of the rod assembly, a first bearing collar, and a second bearing collar, wherein attaching the nut assembly to the tube includes attaching the nut assembly to the tube by crimping at least a portion of the tube into a groove defined in an outer surface of the first bearing collar and crimping at least a portion of the tube into a groove defined in an outer surface of the second bearing collar. 
     
     
         18 . The method of  claim 16 , wherein attaching the tube to the base of the second jaw by crimping a portion of the tube into the groove defined in the base of the second jaw includes crimping a portion of the tube into the groove defined in the base of the second jaw using a plurality of crimp dies, wherein each of the plurality of crimp dies includes a crimping portion, and wherein each of the crimping portions define a crimping edge having a radius of at least ⅛th of an inch. 
     
     
         19 . The method of  claim 16 , further comprising:
 reconditioning the slack adjuster, wherein reconditioning the slack adjuster includes removing the second jaw from the tube by shearing off the portion of the tube crimped into the groove in the base of the second jaw with a plurality of crimp dies.   
     
     
         20 . The method of  claim 16 , further comprising:
 attaching a pawl box to the tube, wherein attaching the pawl box to the tube includes positioning the pawl box over a pawl opening defined in the tube such that at least one locator tab of the pawl box extends into at least one locator opening defined in the tube, and wherein attaching the pawl box to the tube further includes forming a pair of coupling projections around an outer surface of the tube.