{HEAD ~ The upper endges} 451 of the right and left receiving members 481 and 491 of a generally U shaped cross section of retaining side covers 34 and 35 are fixedly received in {TAIL ~ the grooves} 411 and 421  
are fixedly received in
{ HEAD ~ The upper endges } 451 of the right and left receiving members 481 and 491 of a generally U shaped cross section of retaining side covers 34 and 35 are fixedly received in { TAIL ~ the grooves } 411 and 421
HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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 REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH