{HEAD ~ The support unit} has a receiving portion, {TAIL ~ a biasing member}, and a braking unit 
has
{ HEAD ~ The support unit } has a receiving portion , { TAIL ~ a biasing member } , and a braking unit
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH