{TAIL ~ The cam plates} are in {HEAD ~ contact} with the cam surfaces, and serve for positioning the sliding frames 
{ TAIL ~ The cam plates } are in { HEAD ~ contact } with the cam surfaces , and serve for positioning the sliding frames
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH