{HEAD ~ A fan}, with reversible blades, having a hub receiving the stem of the blades and an inner retaining ring, which has {TAIL ~ outwardly extending projections}, supported concentric with the hub 
has
{ HEAD ~ A fan } , with reversible blades , having a hub receiving the stem of the blades and an inner retaining ring , which has { TAIL ~ outwardly extending projections } , supported concentric with the hub
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH