{HEAD ~ All three illustrated plate type swivels} for rotationally supporting {TAIL ~ an article} on a base broadly comprise: a pair of plates and plate spacing and centering means 
{ HEAD ~ All three illustrated plate type swivels } for rotationally supporting { TAIL ~ an article } on a base broadly comprise : a pair of plates and plate spacing and centering means
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH