When the machine is in operation, {HEAD ~ the switch} 80 is pressed by {TAIL ~ the protective cover} 70 such that power is made available to the machine 
When the machine is in operation , { HEAD ~ the switch } 80 is pressed by { TAIL ~ the protective cover } 70 such that power is made available to the machine
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH