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