The holding members are separated or isolated from {HEAD ~ the slider}, to assure {TAIL ~ smooth sliding movement} of the slider 
to assure
The holding members are separated or isolated from { HEAD ~ the slider } , to assure { TAIL ~ smooth sliding movement } of the slider
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH