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