The slider is slidably mounted on {HEAD ~ the lower casing member} so as to cover {TAIL ~ at least a part} of a bottom and a side of the lower casing member 
to cover
The slider is slidably mounted on { HEAD ~ the lower casing member } so as to cover { TAIL ~ at least a part } of a bottom and a side of the lower casing member
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH