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