Anti-Rotation for Eccentric Bushings

Abstract

An attachment system and method that includes first and second fittings, a first eccentric bushing positioned within the first fitting, and a second eccentric bushing positioned within the second fitting. The system may include a first friction washer positioned between the first bushing and first fitting and a second friction washer positioned between the second bushing and the second fitting. A coating on the exterior of the friction washers prohibits rotation of the bushings with respect to the fittings. The coating may be a nickel-diamond coating that prohibits rotation even in the presence of a lubricant. The first fitting may be a frame fitting connected to a fuselage of an aircraft and the second fitting may be a beam fitting connected to the floor of the aircraft. The system may include lock plates that engage lock stops to prohibit rotation of the bushings in combination with the coated friction washers.

What is claimed is: 
     
         1 . An attachment system comprising:
 a first fitting having a first hole;   a second fitting having a second hole, the second fitting positioned adjacent to the first fitting;   a first eccentric bushing, a portion of the first eccentric bushing positioned within the first hole of the first fitting; and   a first friction washer positioned between an another portion of the first eccentric bushing and the first fitting, the first friction washer comprising a coating on an exterior, wherein the coating on the first friction washer prohibits rotation of the first eccentric bushing with respect to the first fitting.   
     
     
         2 . The attachment system of  claim 1 , further comprising:
 a second eccentric bushing, a portion of the second eccentric bushing positioned within the second hole of the second fitting; and   a second friction washer positioned between an another portion of the second eccentric bushing and the second fitting, the second friction washer comprising a coating on an exterior, wherein the coating on the second friction washer prohibits rotation of the second eccentric bushing with respect to the second fitting.   
     
     
         3 . The attachment system of  claim 2 , further comprising a fastener, wherein the fastener extends through the first fitting, the second fitting, the first eccentric bushing, the first friction washer, the second eccentric bushing, and the second friction washer. 
     
     
         4 . The attachment system of  claim 2 , wherein the coating on each of the first and second friction washers comprises a nickel-diamond coating. 
     
     
         5 . The attachment system of  claim 4 , wherein a diamond concentration of the nickel-diamond coating on each of the first and second friction washers is between 8-30%. 
     
     
         6 . The attachment system of  claim 4 , wherein the coating on each of the first and second friction washers has a coefficient of friction of 0.5 or greater when lubricated. 
     
     
         7 . The attachment system of  claim 4 , further comprising at least four attachment points between an aircraft floor and an aircraft fuselage, wherein each attachment point comprises each of the first fitting, the second fitting, the first eccentric bushing, the second eccentric bushing, the first friction washer, and the second friction washer. 
     
     
         8 . The attachment system of  claim 7 , wherein the at least four attachment points are located at corners of the aircraft floor. 
     
     
         9 . The attachment system of  claim 4 , wherein the first fitting comprises a frame fitting connected to a fuselage of an aircraft and wherein the second fitting comprises a beam fitting connected to a floor of the aircraft. 
     
     
         10 . The attachment system of  claim 9 , further comprising a spacer positioned between the first fitting and the second fitting. 
     
     
         11 . The attachment system of  claim 2 , further comprising:
 a first lock plate positioned around a circumference of the first friction washer;   a first lock stop on the first fitting, wherein the first lock plate engages the first lock stop;   a second lock plate positioned around a circumference of the second friction washer; and   a second lock stop on the second fitting, wherein the second lock plate engages the second lock stop.   
     
     
         12 . The attachment system of  claim 1 , further comprising:
 a first lock plate positioned around a circumference of the first friction washer; and   a first lock stop on the first fitting, wherein the first lock plate engages the first lock stop.   
     
     
         13 . A method of attaching a first fitting and a second fitting, the method comprising:
 positioning a portion of a first eccentric bushing within a first hole of a first fitting, the first fitting being positioned adjacent to a second fitting having a second hole;   positioning a first friction washer between an another portion of the first eccentric bushing and the first fitting, wherein an exterior of the first friction washer comprises a coating that prohibits rotation of the first eccentric bushing with respect to the first fitting; and   positioning a fastener through the first fitting, the second fitting, the first eccentric bushing, the first friction washer.   
     
     
         14 . The method of  claim 13 , further comprising:
 positioning a portion of a second eccentric bushing within the second hole of the second fitting; and   positioning a second friction washer between an another portion of a second eccentric bushing and the second fitting, wherein an exterior of the second friction washer comprises a coating that prohibits rotation of the second eccentric bushing with respect to the second fitting.   
     
     
         15 . The method of  claim 14 , wherein the coating on each of the first and second friction washers comprises a nickel-diamond coating. 
     
     
         16 . The method of  claim 14 , further comprising rotating at least one of the first eccentric bushing and the second eccentric bushing to align an opening in the first eccentric bushing with an opening in the second eccentric bushing. 
     
     
         17 . The method of  claim 16 , further comprising:
 positioning a first lock plate around a circumference of the first friction washer;   engaging the first lock plate with a lock stop on the first fitting;   positioning a second lock plate around a circumference of the second friction washer; and   engaging the second lock plate with a lock stop on the second fitting.   
     
     
         18 . The method of  claim 13 , wherein the first fitting comprises a frame fitting connected to a fuselage of an aircraft and wherein the second fitting comprises a beam fitting connected to a floor of the aircraft. 
     
     
         19 . The method of  claim 13 , further comprising positioning a spacer between the first fitting and the second fitting. 
     
     
         20 . An attachment system comprising:
 a first fitting having a first hole;   a second fitting having a second hole, the second fitting positioned adjacent to the first fitting;   a first eccentric bushing, a portion of the first eccentric bushing positioned within the first hole of the first fitting;   a second eccentric bushing, a portion of the second eccentric bushing positioned within the second hole of the second fitting; and   a coating positioned between the first eccentric bushing and the first fitting, wherein the coating prohibits rotation of the first eccentric bushing with respect to the first fitting; and   a coating positioned between the second eccentric bushing and the second fitting, wherein the coating prohibits rotation of the second eccentric bushing with respect to the second fitting.