Alternatively, {HEAD ~ such struts} may constitute {TAIL ~ shutters} joining to the tube body by resilient hinges and pivotable about such hinges between such radially inner and outer positions 
constitute
Alternatively , { HEAD ~ such struts } may constitute { TAIL ~ shutters } joining to the tube body by resilient hinges and pivotable about such hinges between such radially inner and outer positions
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH