As shown in FIG 20, the section of the inner ring 153 is shaped like a fallen L and the section of the outer ring 152 is a rectangle seated on {HEAD ~ the L shaped section} of {TAIL ~ the inner ring} 153 
of
As shown in FIG 20 , the section of the inner ring 153 is shaped like a fallen L and the section of the outer ring 152 is a rectangle seated on { HEAD ~ the L shaped section } of { TAIL ~ the inner ring } 153
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH