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