The drivers are driven such that they carry out {HEAD ~ a conveying displacement} in the conveying direction and a return displacement in {TAIL ~ the opposite direction} 
The drivers are driven such that they carry out { HEAD ~ a conveying displacement } in the conveying direction and a return displacement in { TAIL ~ the opposite direction }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL