Roller tensioning assembly

Abstract

An adjustable roller assembly for a linear rail system carriage has an indexing collar, an eccentric bushing, an adjustable roller, a suspension element, and an adjustment collar. The indexing collar has a first indexing structure. The adjustable roller is rollably mounted to a roller side end of the eccentric bushing. A rolling axis of the adjustable roller is offset from the axis of the adjustable roller assembly. The suspension element is mounted in axial alignment with an adjustment side end of the eccentric bushing. The adjustment collar has a circumferential flange having a second indexing structure. The first indexing structure and the second indexing structure are coupled to rotationally couple the adjustment collar with the suspension element.

What is claimed is: 
     
         1 . An adjustable roller assembly for a linear rail system carriage, the adjustable roller assembly having an axis and comprising:
 as indexing collar having a first indexing structure;   an eccentric bushing having an adjustment side end and a roller side end opposite the adjustment side end;   an adjustable roller rollably mounted to the roller side end of the eccentric bushing, wherein a rolling axis of the adjustable roller is offset from the axis of the adjustable roller assembly;   a suspension element comprising an inner core and an outer sleeve torsionally elastically coupled to the inner core, wherein the inner core is fixedly mounted to the adjustment side end of the eccentric bushing with the suspension element in axial alignment with the eccentric bushing; and   an adjustment collar having a circumferential flange having a second indexing structure, wherein the first indexing structure and the second indexing structure are coupled to rotationally couple the adjustment collar with the suspension element.   
     
     
         2 . The adjustable roller assembly of  claim 1 , wherein:
 the first indexing structure comprises a plurality of circularly-spaced indexing holes; and   the second indexing structure comprises at least one indexing slot positioned for selective alignment with the indexing holes of the indexing collar.   
     
     
         3 . The adjustable roller assembly of  claim 2 , further comprising:
 at least one indexing pin, wherein each indexing pin is positioned in a corresponding indexing slot and a corresponding indexing hole to rotationally couple the adjustment collar with the indexing collar, thereby maintaining a rotational position of the eccentric bushing.   
     
     
         4 . The adjustable roller assembly of  claim 3 , wherein:
 the at least one indexing pin is a threaded fastener, and each of the at least one indexing hole is a corresponding tapped hole.   
     
     
         5 . The adjustable roller assembly of  claim 2 , wherein:
 the indexing collar has an annular face and the plurality of indexing holes are formed and circumferentially spaced in the annular face; and   the circumferential flange of the adjustment collar has a plurality of the indexing slots circumferentially-spaced for selective alignment with corresponding ones of the indexing holes of the indexing collar.   
     
     
         6 . The adjustable roller assembly of  claim 1 , wherein:
 the outer sleeve of the suspension element has a first mating structure;   the adjustment collar has a second mating structure; and   the adjustment collar is removably coupled with the suspension element by mating of the first mating structure and the second mating structure.   
     
     
         7 . The adjustable roller assembly of  claim 6 , wherein:
 the suspension element is cylindrical;   the first mating structure is formed on a radially outer surface of the outer sleeve;   the adjustment collar forms a cylindrical channel, and the second mating structure is formed at an inner surface of the cylindrical channel; and   the suspension element is nested in axial alignment with the cylindrical channel, with the first mating structure and the second mating structure mated.   
     
     
         8 . The adjustable roller assembly of  claim 6 , wherein:
 the first mating structure and the second mating structure form a spline-and-groove arrangement.   
     
     
         9 . The adjustable roller assembly of  claim 1 , wherein:
 the eccentric bushing has at least one tapped adjustment side fastener bore formed in the adjustment side end; and   the suspension element is mounted to the eccentric bushing by at least one suspension element threaded fastener mated with the one tapped adjustment side fastener bore.   
     
     
         10 . The adjustable roller assembly of  claim 1 , wherein:
 the eccentric bushing has a tapped roller side fastener bore formed in the roller side end; and   the adjustable roller is mounted to the eccentric bushing by an adjustable roller threaded fastener mated with the tapped roller side fastener bore of the eccentric bushing.   
     
     
         11 . The adjustable roller assembly of  claim 10 , wherein:
 the tapped roller side fastener bore is axially aligned with the rolling axis of the adjustable roller offset from the axis of the adjustable roller assembly.   
     
     
         12 . A carriage for a linear rail system, the carriage comprising:
 a platform having a roller side, an adjustment side opposite the roller side, and a bushing bore;   a fixed roller assembly mounted to the platform, the fixed roller assembly comprising a fixed roller rollably mounted at the roller side of the platform; and   the adjustable roller assembly of  claim 1  mounted to the platform,   wherein:
 the indexing collar is fixed at the adjustment side of the platform in axial alignment with the bushing bore; 
 the eccentric bushing is installed in the bushing bore; and 
 the adjustable roller is rollably mounted to the roller side end of the eccentric bushing at the roller side of the platform. 
   
     
     
         13 . The carriage of  claim 12 , wherein:
 the adjustment collar is rotatable to adjust a spacing between a fixed rolling axis of the fixed roller and a rolling axis of the adjustable roller.   
     
     
         14 . The carriage of  claim 13 , wherein:
 the suspension element is operable to vary the spacing between the rolling axis of the fixed roller and the rolling axis of the adjustable roller within predetermined limits responsive to forces applied to at least one of the fixed roller and the adjustable roller.   
     
     
         15 . The carriage of  claim 13  comprising multiple pairs of the fixed roller assembly and the adjustable roller assembly. 
     
     
         16 . A kit for an adjustable roller assembly for a linear rail system carriage, the kit comprising:
 as indexing collar having a first indexing structure;   an eccentric bushing having an adjustment side end and a roller side end opposite the adjustment side end;   a suspension element comprising an inner core and an outer sleeve torsionally elastically coupled to the inner core, wherein the inner core is fixedly mountable to the adjustment side end of the eccentric bushing with the suspension element in axial alignment with the eccentric bushing; and   an adjustment collar having a circumferential flange having a second indexing structure, wherein the first indexing structure and the second indexing structure are couplable to rotationally couple the adjustment collar with the suspension element.   
     
     
         17 . The kit of  claim 16 , further comprising:
 instructions for assembling the adjustable roller assembly.