The arrangement of the support pulleys and endless cable is such that by operation of the winder pulley , {TAIL ~ the cover} is retractably moved over the top of {HEAD ~ the trailer body}  
The arrangement of the support pulleys and endless cable is such that by operation of the winder pulley , { TAIL ~ the cover } is retractably moved over the top of { HEAD ~ the trailer body }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH