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