The shaped bar is removed from {HEAD ~ the chamber bottom end}, upon opening the bottom wall, by shifting it to an opened position laterally offset from {TAIL ~ the open bottom end} of the chamber 
The shaped bar is removed from { HEAD ~ the chamber bottom end } , upon opening the bottom wall , by shifting it to an opened position laterally offset from { TAIL ~ the open bottom end } of the chamber
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH