A retractable cover system for {HEAD ~ a tipper trailer body} of {TAIL ~ a truck}, said retractable cover system comprising: 
of
A retractable cover system for { HEAD ~ a tipper trailer body } of { TAIL ~ a truck } , said retractable cover system comprising :
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH