Means are provided to prevent jumping of the belt from {HEAD ~ the second pulley} when the head is in {TAIL ~ other positions} 
Means are provided to prevent jumping of the belt from { HEAD ~ the second pulley } when the head is in { TAIL ~ other positions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL