a second sleeve surrounding the first mentioned sleeve and of {HEAD ~ a material} substantially more resistant to {TAIL ~ wear} than the first sleeve; the cover being molded on the yoke, and forming a separate element complementarily fitted to the yoke 
substantially more resistant to
a second sleeve surrounding the first mentioned sleeve and of { HEAD ~ a material } substantially more resistant to { TAIL ~ wear } than the first sleeve ; the cover being molded on the yoke , and forming a separate element complementarily fitted to the yoke
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH