The control cam and a contact surface of the feeler roller are in operative rolling contact during at least part of {HEAD ~ a period} repeating in {TAIL ~ the respective periods} 
repeating in
The control cam and a contact surface of the feeler roller are in operative rolling contact during at least part of { HEAD ~ a period } repeating in { TAIL ~ the respective periods }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL