In this way, {HEAD ~ the bellows} covers {TAIL ~ the upper portion} of the canvas belt on the upper side 
In this way , { HEAD ~ the bellows } covers { TAIL ~ the upper portion } of the canvas belt on the upper side
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH