S cam assembly

Abstract

An S cam assembly, includes an S cam member having a shank, the shank having a machined shank outer margin, a tubular bushing holder member disposable annular to the shank, and a single S cam bushing member disposable intermediate the shank machined shank outer margin and an inside margin of the bushing holder when the bushing holder is in the annular disposition relative to the shank.

1 . A support assembly for supporting an S cam, the S cam being an intermediary device between a brake actuator and a set of wheel brakes and is generally formed with an elongate metal shank having an S-head at a first end of the shank and a set of splines at a second end of the shank, the S-head having at least one arm for engaging a respective brake shoe, whereby rotation of the S cam in a first direction causes the at least one arm of the S-head to act on the brake shoe to frictionally engage the brake shoe with a brake drum, the brake drum being affixed to a wheel, comprising:
 a single bushing rotationally supporting the S cam, the bushing extending along the S cam shank from proximate the S-head to proximate the splines, the bushing being substantially sealed within a bushing holder by a first seal member and second seal member disposed proximate first and second ends of the bushing respectively, each of the seal members forming a sealing interface with the bushing holder and the s cam shank.   
     
     
         2 . The support assembly of  claim 1 , the bushing being formed of a plastic material. 
     
     
         3 . The support assembly of  claim 1 , the bushing being substantially enclosed within the bushing holder. 
     
     
         4 . The support assembly of  claim 3 , an outside diameter of the bushing being sized to form a substantially tight fit with an inside diameter of the bushing holder. 
     
     
         5 . The support assembly of  claim 3 , the bushing holder having at least one grease fitting disposed in a bore defined through a bushing holder body for transporting lubricant to the inside margin of the bushing holder. 
     
     
         6 . The support assembly of  claim 5 , the grease fitting intersecting a circumferential groove defined in the bushing holder inside margin. 
     
     
         7 . The support assembly of  claim 6 , the circumferential groove intersecting at least one spiral groove defined in the bushing holder inside margin. 
     
     
         8 . The support assembly of  claim 7 , the circumferential groove and the at least one spiral groove defined in the bushing holder inside diameter forming a path for lubricating the interface defined between the bushing and the bushing holder. 
     
     
         9 . The support assembly of  claim 1 , an S cam shank outside margin being spaced apart from an inside margin of the bushing by an amount of between 0.001 and 0.010 inches. 
     
     
         10 . A support assembly for supporting an S cam, the S cam being an intermediary device between a brake actuator and a set of wheel brakes and being generally formed with an elongate metal shank having an S-head at a first end of the shank and a set of splines at a second end of the shank, the S-head having at least one arm for engaging a respective brake shoe, whereby rotation of the S cam in a first direction causes the at least one arm of the S-head to act on the brake shoe to frictionally engage the brake shoe with a brake drum, comprising:
 a single bushing rotationally supporting the S cam, the bushing extending along the shank from proximate the S-head to proximate the splines, the S cam shank outside margin being spaced apart from an inside margin of the bushing.   
     
     
         11 . A support assembly for supporting an S cam, the S cam having a generally elongate metal shank and having an S-head at a first end the shank and a set of splines at a second end of the shank comprising:
 a bushing holder;   a single bushing rotationally supporting the S cam, the bushing being substantially enclosed within the bushing holder; and   the bushing being substantially sealed within a bushing holder by a first and second seal members disposed proximate a first and a second end of the bushing respectively, each of the seal members forming a sealing interface with the bushing holder and the S cam shank.   
     
     
         12 . The support assembly of  claim 11 , the bushing being substantially coextensive with the S cam shank. 
     
     
         13 . The support assembly of  claim 11 , the bushing extending along the S cam shank from proximate the S-head to proximate the splines. 
     
     
         14 . The support assembly of  claim 11 , the bushing being formed of a plastic material. 
     
     
         15 . The support assembly of  claim 11 , an outside diameter of the bushing being sized to form a generally tight fit with an inside diameter of the bushing holder. 
     
     
         16 . The support assembly of  claim 11 , the bushing holder having at least one grease fitting disposed in a bore defined through a bushing holder body for transporting lubricant to the inside margin of the bushing holder. 
     
     
         17 . The support assembly of  claim 16 , the grease fitting intersecting a circumferential groove defined in the bushing holder inside margin. 
     
     
         18 . The support assembly of  claim 17 , the circumferential groove intersecting at least one spiral groove defined in the bushing holder inside margin. 
     
     
         19 . The support assembly of  claim 18 , the circumferential groove and the at least one spiral groove defined in the bushing holder inside diameter forming a path for lubricating the interface defined between the bushing and the bushing holder. 
     
     
         20 . An S cam assembly, comprising:
 a S cam member having a shank, the shank having a machined shank outer margin;   a tubular bushing holder disposable annular to the shank; and   a single S cam bushing disposable intermediate the shank machined shank outer margin and an inside margin of the bushing holder when the bushing holder is in the annular disposition relative to the shank.   
     
     
         21 . The S cam assembly of  claim 20 , the bushing being substantially sealed within the bushing holder by a first and a second seal member, the first and second seal members being disposed proximate first and second ends of the bushing respectively. 
     
     
         22 . The S cam assembly of  claim 20 , the machined shank outer margin being formed with a substantially smooth surface. 
     
     
         23 . The S cam assembly of  claim 20 , the machined shank outer margin having a uniform diameter. 
     
     
         24 . The S cam assembly of  claim 20 , the bushing member being press fit into the bushing holder member.