{HEAD ~ An annular space} is furnished between the internal lateral wall of the circular cap and {TAIL ~ the lateral wall} of the cone frustrum, and the horizontal peripheral edge is in contact with the rubbing plate 
is furnished between
{ HEAD ~ An annular space } is furnished between the internal lateral wall of the circular cap and { TAIL ~ the lateral wall } of the cone frustrum , and the horizontal peripheral edge is in contact with the rubbing plate
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH