a pair of shafts provided at {HEAD ~ one end} with {TAIL ~ the paired horizontal rollers} and at the other end with mutually engageable gear wheels, 
with
a pair of shafts provided at { HEAD ~ one end } with { TAIL ~ the paired horizontal rollers } and at the other end with mutually engageable gear wheels ,
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH