Advantageously, {TAIL ~ the relative stacking motion} is stopped by the abutment of the lower cone knob 30 on the upper cone interior surface 52 before the upper cone has descended onto the lower cone sufficiently to create {HEAD ~ a jamming or sticking problem} 
Advantageously , { TAIL ~ the relative stacking motion } is stopped by the abutment of the lower cone knob 30 on the upper cone interior surface 52 before the upper cone has descended onto the lower cone sufficiently to create { HEAD ~ a jamming or sticking problem }
OTH OTH TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD