The dolly assembly is used to unwind {TAIL ~ the wound strip} of {HEAD ~ material} from the roll and position it on the roof to facilitate its seam welding to an adjacent strip of material 
The dolly assembly is used to unwind { TAIL ~ the wound strip } of { HEAD ~ material } from the roll and position it on the roof to facilitate its seam welding to an adjacent strip of material
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH